WO2021240882A1

WO2021240882A1 - Polarizing plate with retardation layer and adhesive layer and organic electroluminescence display device using same

Info

Publication number: WO2021240882A1
Application number: PCT/JP2021/003063
Authority: WO
Inventors: 潤枝長田; 雄祐外山
Original assignee: 日東電工株式会社
Priority date: 2020-05-28
Filing date: 2021-01-28
Publication date: 2021-12-02
Also published as: JP2021189259A; CN115698784A; KR20230016182A; TW202206282A

Abstract

Provided is a polarizing plate with a retardation layer and an adhesive layer, said polarizing plate having excellent durability in a high-temperature, high-humidity environment, and also exhibiting significantly suppressed decoloration when employed in an organic EL display device. This polarizing plate with a retardation layer and an adhesive layer has: a polarizing plate including a polarizer and a protective layer on at least the visible side of the polarizer; a retardation layer bonded to the side opposite to the visible side of the polarizing plate, with a first adhesive layer interposed therebetween; and a second adhesive layer arranged, as the outermost layer, on the retardation layer at the side opposite to the polarizing plate. The first adhesive layer or the second adhesive layer contains an acrylic acid as a monomer component of a base polymer, and also contains an inorganic cationic salt conductive agent. The content of the conductive agent is 0.4-12 parts by weight with respect to 100 parts by weight of the base polymer of the adhesive layer.

Description

Polarizing plate with retardation layer and adhesive layer and organic electroluminescence display device using it

The present invention relates to a polarizing plate with a retardation layer and an adhesive layer, and an organic electroluminescence (EL) display device using the same.

In recent years, with the spread of thin displays, displays (organic EL display devices) equipped with organic EL panels have been proposed. Since the organic EL panel has a highly reflective metal layer, problems such as external light reflection and background reflection are likely to occur. Therefore, it is known to prevent these problems by providing a circularly polarizing plate on the visual recognition side (for example, Patent Documents 1 to 3). However, there is a problem that the circularly polarizing plate provided in the organic EL display device is easily decolorized. Further, in the circularly polarizing plate, improvement of durability in a high temperature and high humidity environment is continuously required.

Japanese Unexamined Patent Publication No. 2003-31239 Japanese Unexamined Patent Publication No. 2002-372622 Japanese Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is excellent durability in a high temperature and high humidity environment, and remarkably suppresses decolorization when applied to an organic EL display device. It is an object of the present invention to provide a polarizing plate with a retardation layer and a pressure-sensitive adhesive layer.

The polarizing plate with a retardation layer and a pressure-sensitive adhesive layer of the present invention comprises a polarizing plate containing a polarizing element and a protective layer at least on the visible side of the polarizing element, and a first pressure-sensitive adhesive on the side opposite to the visible side of the polarizing plate. It has a retardation layer bonded via a layer and a second pressure-sensitive adhesive layer arranged as an outermost layer on the opposite side of the retardation layer to the polarizing plate. The first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer contains acrylic acid as a monomer component of the base polymer and contains a conductive agent of an inorganic cationic salt. The content of the conductive agent is 0.4 parts by weight to 12 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
In one embodiment, the acrylic acid content in the monomer component is 0.1% by weight to 10% by weight.
In one embodiment, the first pressure-sensitive adhesive layer contains acrylic acid as a monomer component of the base polymer and contains a conductive agent of an inorganic cationic salt.
In one embodiment, the polarizing element and the retardation layer are bonded to each other via the first pressure-sensitive adhesive layer.
In one embodiment, the inorganic cation salt is a lithium salt.
In one embodiment, the moisture permeability of the protective layer of the viewing side is less 200g ^/ m 2 · 24h.
According to another aspect of the invention, an organic electroluminescence display device is provided. This organic electroluminescence display device includes the above-mentioned retardation layer and a polarizing plate with an adhesive layer.

According to the embodiment of the present invention, in the polarizing plate with a retardation layer and the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer in which the polarizing plate and the retardation layer are laminated or the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer is used as an image display cell. Durability in a high temperature and high humidity environment by introducing a predetermined amount of a conductive agent (inorganic cationic salt) into the pressure-sensitive adhesive layer for bonding and containing acrylic acid as a monomer component of the base polymer of the pressure-sensitive adhesive layer. It is possible to realize a polarizing plate with a retardation layer and an adhesive layer, which is excellent in quality and whose decolorization is remarkably suppressed when applied to an organic EL display device.

It is schematic cross-sectional view of the polarizing plate with a retardation layer and an adhesive layer by 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 herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the refractive index in the plane is maximized (that is, the direction of the slow phase axis), and "ny" is the direction orthogonal to the slow phase axis in the plane (that is, the direction of the phase advance axis). 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. For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is obtained by the formula: Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Phase difference in the thickness direction (Rth)
“Rth (λ)” is a phase difference in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, "Rth (550)" is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is obtained by the formula: Rth (λ) = (nx-nz) × d, where d (nm) is the thickness of the layer (film).
(4) Nz coefficient The Nz coefficient is obtained by Nz = Rth / Re.
(5) Angle When referring to an angle herein, the angle includes both clockwise and counterclockwise with respect to the reference direction. Therefore, for example, "45 °" means ± 45 °.

A. Overall Configuration of Polarizing Plate with Phase Difference Layer and Adhesive Layer FIG. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer and a pressure-sensitive adhesive layer according to one embodiment of the present invention. The polarizing plate 100 with the retardation layer and the pressure-sensitive adhesive layer in the illustrated example includes the polarizing plate 10, the retardation layer 30 bonded to the polarizing plate 10 via the first pressure-sensitive adhesive layer 20, and the retardation layer 30. It has a second pressure-sensitive adhesive layer 40 provided as an outermost layer on the side opposite to the polarizing plate 10. The second pressure-sensitive adhesive layer 40 makes it possible to attach the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer to the image display cell. The polarizing plate 10 includes a polarizing element 11 and a protective layer (viewing side protective layer) 12 at least on the viewing side of the polarizing element 11. In the illustrated example, the protective layer (inner protective layer) 13 is provided on the side opposite to the visible side of the polarizing element 11, but the protective layer 13 may be preferably omitted. That is, the polarizing element 11 and the retardation layer 30 can be bonded to each other via the first pressure-sensitive adhesive layer 20. In the configuration in which the inner protective layer 13 is omitted, the effect of the embodiment of the present invention is remarkable. Practically, it is preferable that a release film is temporarily attached to the surface of the second pressure-sensitive adhesive layer 40 until the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer are used. Temporarily attaching the release film protects the second pressure-sensitive adhesive layer and enables roll formation of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer.

In the embodiment of the present invention, the first pressure-sensitive adhesive layer 20 or the second pressure-sensitive adhesive layer 40 contains acrylic acid as a monomer component of the base polymer and also contains a conductive agent of an inorganic cationic salt. By introducing the conductive agent of the inorganic cationic salt and acrylic acid in combination into either the first pressure-sensitive adhesive layer 20 or the second pressure-sensitive adhesive layer 40, the durability in a high-temperature and high-humidity environment is excellent, and It is possible to realize a polarizing plate with a retardation layer and an adhesive layer in which decolorization is significantly suppressed when applied to an organic EL display device. The present inventors face a new problem that when a polarizing plate with a retardation layer and a pressure-sensitive adhesive layer is applied to an organic EL display device, the polarizing plate with a retardation layer and a pressure-sensitive adhesive layer is decolorized. As a result of diligent studies, it was discovered that the cause of the decolorization was ammonia (substantially ammonium ions) generated from the organic EL panel. Furthermore, as a result of diligent studies on means for suppressing decolorization due to ammonia, a pressure-sensitive adhesive layer for laminating a polarizing plate and a retardation layer, or a pressure-sensitive adhesive for bonding a polarizing plate with a retardation layer and a pressure-sensitive adhesive layer to an image display cell. It has been discovered that the decolorization can be remarkably suppressed by introducing a predetermined amount of a conductive agent (inorganic cationic salt) into the layer and containing acrylic acid as a monomer component of the base polymer of the pressure-sensitive adhesive layer. That is, the embodiment of the present invention solves such a newly discovered problem. The conductive agent (inorganic cationic salt) is preferably a lithium salt. The content of the conductive agent is 0.4 parts by weight to 12 parts by weight, preferably 0.5 parts by weight to 10 parts by weight, and more preferably 2 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer. Parts to 8 parts by weight. If the conductive agent content is too high, the durability of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer in a high-temperature and high-humidity environment may be insufficient. If the conductive agent content is too low, the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer may be decolorized when applied to the organic EL display device. The acrylic acid content in the monomer component is preferably 0.1% by weight to 10% by weight, more preferably 0.2% by weight to 8% by weight, still more preferably 0.2% by weight to 6% by weight. %. By introducing acrylic acid into the monomer component of the base polymer of either the first pressure-sensitive adhesive layer 20 or the second pressure-sensitive adhesive layer 40, the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer are applied to an organic EL display device. If this is the case, decolorization can be significantly suppressed. Preferably, the first pressure-sensitive adhesive layer 20 contains acrylic acid as a monomer component of the base polymer and contains a conductive agent of an inorganic cationic salt. With such a configuration, the effect of the embodiment of the present invention is remarkable. It is presumed that this is because the cation of the conductive agent (typically, lithium ion) not only captures the ammonium ion but also stabilizes the iodine complex in the substituent by the lithium ion. It should be noted that such an estimation is neither limiting nor binding to the estimation of the present invention. Further, the effect that the first pressure-sensitive adhesive layer contains a conductive agent and the like is particularly remarkable in the configuration in which the inner protective layer 13 is omitted. Since the first pressure-sensitive adhesive layer is adjacent to the stator, it is presumed that the transfer of lithium ions to the ligand and the binding to the iodine complex (substantially the iodine ions in the complex) are facilitated.

Moisture permeability of the viewing side protective layer 12 is typically not more than 200g ^/ m 2 · 24h, preferably not more than 160g ^/ m 2 · 24h, more preferably not more than 100g ^/ m 2 · 24h, further preferably not more than 50g ^/ m 2 · 24h, most preferably not more than 30g ^/ m 2 · 24h. The lower limit of the moisture permeability of the viewing side protective layer 12 may be, for example, 1g ^/ m 2 · 24h. By omitting the inner protective layer 13 and setting the moisture permeability of the visible side protective layer 12 in such a range, the effect of containing the conductive agent and acrylic acid in the pressure-sensitive adhesive layer becomes remarkable. The moisture permeability can be measured according to JIS Z 0208.

The total thickness of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer is preferably 120 μm or less, and more preferably 100 μm or less. The lower limit of the total thickness can be, for example, 45 μm. A polarizing plate with a retardation layer and an adhesive layer having such a total thickness can have extremely excellent flexibility and bending durability. As a result, the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer may be particularly preferably applied to a curved organic EL display device and / or a bendable or bendable organic EL display device.

The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer may further have another retardation layer (not shown) between the retardation layer 30 and the second pressure-sensitive adhesive layer 40. Another retardation layer is typically a so-called positive C plate in which the refractive index characteristic shows a relationship of nz> nx = ny. By providing such another retardation layer, it is possible to satisfactorily prevent reflection in the oblique direction, and it is possible to widen the viewing angle of the antireflection function.

The retardation layer and the polarizing plate with the pressure-sensitive adhesive layer may further include other optical functional layers. The type, characteristics, number, combination, arrangement position, and the like of the optical functional layers that can be provided on the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer can be appropriately set according to the purpose. For example, the retarding layer and the polarizing plate with the pressure-sensitive adhesive layer may further have a conductive layer or an isotropic substrate with a conductive layer (neither is shown). The conductive layer or the isotropic base material with the conductive layer is typically provided on the outside of the retardation layer 30 (on the opposite side of the polarizing plate 10). When a conductive layer or an isotropic substrate with a conductive layer is provided, the retardation layer and the polarizing plate with an adhesive layer are so-called inner touch panel type input display devices in which a touch sensor is incorporated between the organic EL cell and the polarizing plate. Can be applied to. Further, for example, the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer may further include other retardation layers. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, and the like of the other retardation layers can be appropriately set according to the purpose.

The retardation layer and the polarizing plate with the pressure-sensitive adhesive layer may be single-wafer-shaped or long-shaped. As used herein, the term "long" means an elongated shape having a length sufficiently long with respect to the width, and for example, an elongated shape having a length of 10 times or more, preferably 20 times or more with respect to the width. include. The elongated retardation layer and the polarizing plate with the pressure-sensitive adhesive layer can be wound in a roll shape.

Hereinafter, the components of the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer will be described in more detail.

B. Polarizing plate B-1. Polarizer As the polarizing element 11, any suitable polarizing element may be adopted. For example, the resin film forming the polarizing element may be a single-layer resin film or a laminated body having two or more layers.

Specific examples of the polarizing element 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-based partially saponified film. Examples thereof include those which have been dyed and stretched with a bicolor substance such as iodine and 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 properties, a polarizing element obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film 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. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Further, it may be dyed after being stretched. If necessary, the PVA-based film is subjected to a swelling treatment, a crosslinking treatment, a cleaning 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 and blocking inhibitor on the surface of the PVA-based film, but also to swell the PVA-based film to prevent uneven dyeing. Can be prevented.

Specific examples of the polarizing element 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 polarizing element obtained by using a laminate with a PVA-based resin layer coated and formed on a base material. The polarizing element 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; and stretching and dyeing the laminate to make the PVA-based resin layer a stator. obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further comprise, 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 / polarizing element laminate may be used as it is (that is, the resin base material may be used as a protective layer for the polarizing element), and the resin base material is peeled off from the resin base material / polarizing element laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface and used. Details of the method for producing such a polarizing element are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The entire description of these publications is incorporated herein by reference.

The thickness of the polarizing element is preferably 15 μm or less, more preferably 12 μm or less, still more preferably 10 μm or less, and particularly preferably 8 μm or less. On the other hand, the thickness of the polarizing element is preferably 1 μm or more, more preferably 2 μm or more, and further preferably 3 μm or more. When the thickness of the polarizing element is within such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.

The polarizing element preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizing element is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

B-2. Protective Layer The visible side protective layer 12 and the inner protective layer 13 (if any) are each composed of any suitable film that can be used as a protective layer for the polarizing element. Typical materials constituting the inner protective layer 13 include cycloolefin resins such as polynorbornene, (meth) acrylic resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polyester resins such as polyethylene terephthalate (PEN). Examples thereof include polyolefin-based resins such as polyethylene and polycarbonate-based resins. A typical example of the (meth) acrylic resin is a (meth) acrylic resin having a lactone ring structure. Examples of the (meth) acrylic resin having a lactone ring structure include JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, and JP-A-2005. -146084 is described in the publication. These publications are incorporated herein by reference. The inner protective layer 13 (if present) is preferably composed of a cycloolefin-based resin. Typical examples of the material constituting the visible side protective layer 12 include a cellulosic resin such as triacetyl cellulose (TAC) and a resin capable of forming a microporous film (for example, a polyurethane resin).

The retardation layer and the polarizing plate with the adhesive layer are typically arranged on the visual recognition side of the organic EL display device as described later, and the visual recognition side protective layer 12 is arranged on the visual recognition side thereof. Therefore, the visible side protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, sticking prevention treatment, and antiglare treatment, if necessary. Further / or, if necessary, the visual-viewing side protective layer 12 is provided with a process for improving visibility when visually recognizing through polarized sunglasses (typically, a (elliptical) circularly polarized light function is provided. (To give a high phase difference) may be applied. By performing such processing, excellent visibility can be realized even when the display screen is visually recognized through a polarizing lens such as polarized sunglasses. Therefore, the retarding layer and the polarizing plate with the pressure-sensitive adhesive layer can be suitably applied to an organic EL display device that can be used outdoors.

The thickness of the visible side protective layer 12 is preferably 10 μm to 80 μm, more preferably 15 μm to 70 μm, and further preferably 20 μm to 50 μm. When the surface treatment is applied, the thickness of the visible side protective layer 12 is the thickness including the thickness of the surface treatment layer.

The inner protective layer 13 is preferably optically isotropic in one embodiment. As used herein, "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. The thickness of the inner protective layer 13 can also be appropriately set according to the desired moisture permeability. The thickness of the inner protective layer 13 is preferably 10 μm to 80 μm, more preferably 20 μm to 70 μm, and even more preferably 30 μm to 50 μm. As mentioned above, the protective layer 13 may be preferably omitted.

C. Phase difference layer The phase difference layer 30 may be a single layer or may have a laminated structure (substantially a two-layer structure).

When the retardation layer 30 is a single layer, the retardation layer 30 can typically function as a λ / 4 plate. The retardation layer is typically provided to impart antireflection characteristics to the organic EL display device. The retardation layer typically shows a relationship in which the refractive index characteristic is nx> ny = nz. The in-plane retardation Re (550) of the retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 120 nm to 160 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 or ny <nz may occur within a range that does not impair the effect of the present invention.

The Nz coefficient of the retardation layer is preferably 0.9 to 1.5, and more preferably 0.9 to 1.3. By satisfying such a relationship, an organic EL display device having a very excellent reflected hue can be obtained.

When the retardation layer is a single layer, the retardation layer preferably exhibits a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. In this case, Re (450) / Re (550) of the retardation layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized.

The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and even more preferably about 45 °. When the angle is in such a range, an organic EL display device having very excellent antireflection characteristics can be obtained by using the retardation layer as a λ / 4 plate as described above.

The retardation layer can be made of any suitable material as long as the above characteristics can be satisfied. Specifically, the retardation layer may be a stretched film of a resin film or an oriented solidified layer of a liquid crystal compound (hereinafter, a liquid crystal oriented solidified layer).

When the retardation layer is a stretched film of a resin film, typical examples of the resin constituting the resin film include a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter, may be simply referred to as a polycarbonate-based resin). As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as the desired moisture permeability can be obtained. For example, the polycarbonate-based resin has a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based 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-based resin is a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol, and / or di, tri or polyethylene glycol. Containing structural units derived from; more preferably structural units derived from fluorene dihydroxy compounds, structural units derived from isosorbide dihydroxy compounds, and structural units derived from di, tri or polyethylene glycol. .. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds, if necessary. The retardation layer can be formed by stretching a film made of the polycarbonate-based resin as described above under any appropriate stretching conditions. For details of the method for forming the polycarbonate resin and the retardation layer, see, for example, JP-A-2014-10291, JP-A-2014-226666, JP-A-2015-21816, JP-A-2015-21217. It is described in JP-A-2015-212818, JP-A-2017-54093, and JP-A-2018-60014. The description of these publications is incorporated herein by reference.

When the retardation layer is a liquid crystal oriented solidified layer, the difference between nx and ny of the obtained retardation layer can be significantly increased as compared with the non-liquid crystal material by using the liquid crystal compound, so that the desired surface can be obtained. The thickness of the retardation layer for obtaining the internal phase difference can be significantly reduced. As a result, it is possible to further reduce the thickness of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer (as a result, the organic EL display device). As used herein, the term "aligned solidified layer" refers to a layer in which a liquid crystal compound is oriented in a predetermined direction within the layer and the oriented state is fixed. The "oriented solidified layer" is a concept including an oriented cured layer obtained by curing a liquid crystal monomer. In the present embodiment, the rod-shaped liquid crystal compounds are typically oriented in a state of being aligned in the slow axis direction of the retardation layer (homogeneous orientation). Specific examples of the liquid crystal compound and details of the method for forming the liquid crystal oriented solidified layer are described in, for example, JP-A-2006-163343 and JP-A-2006-178389. The description of these publications is incorporated herein by reference.

The thickness of the retardation layer can be typically set to a thickness that can properly function as a λ / 4 plate. When the retardation layer is a stretched film of a resin film, the thickness of the retardation layer can be, for example, 10 μm to 60 μm. When the retardation layer is a liquid crystal oriented solidification layer, the thickness of the retardation layer can be, for example, 1 μm to 5 μm.

When the retardation layer has a laminated structure, the retardation layer typically has a two-layer structure of a first liquid crystal oriented solidified layer and a second liquid crystal oriented solidified layer. In this case, either one of the first liquid crystal oriented solidified layer or the second liquid crystal oriented solidified layer can function as a λ / 2 plate, and the other can function as a λ / 4 plate. Here, the case where the first liquid crystal oriented solidified layer can function as a λ / 2 plate and the second liquid crystal oriented solidified layer can function as a λ / 4 plate will be described, but these may be reversed. .. The thickness of the first liquid crystal oriented solidified layer can be adjusted to obtain the desired in-plane phase difference of the λ / 2 plate, and can be, for example, 2.0 μm to 4.0 μm. The thickness of the second liquid crystal oriented solidified layer can be adjusted to obtain the desired in-plane phase difference of the λ / 4 plate, and can be, for example, 1.0 μm to 2.5 μm. The in-plane retardation Re (550) of the first liquid crystal oriented solidified layer is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and further preferably 250 nm to 280 nm. As described above, the in-plane retardation Re (550) of the second liquid crystal oriented solidified layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 120 nm to 160 nm. The angle formed by the slow axis of the first liquid crystal oriented solidified layer and the absorption axis of the polarizing element is preferably 10 ° to 20 °, more preferably 12 ° to 18 °, and further preferably about 15 °. Is. The angle formed by the slow axis of the second liquid crystal oriented solidified layer and the absorption axis of the polarizing element is preferably 70 ° to 80 °, more preferably 72 ° to 78 °, and further preferably about 75 °. Is. With such a configuration, it is possible to obtain characteristics close to the ideal reverse wavelength dispersion characteristics, and as a result, it is possible to realize extremely excellent antireflection characteristics.

D. First adhesive layer and second adhesive layer D-1. Outline of the First Adhesive Layer and the Second Adhesive Layer The first adhesive layer and the second adhesive layer may be composed of the same adhesive, or may be composed of different adhesives. You may. Composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer (for example, type of base polymer (polarity, Tg, softness), molecular weight), cross-linking structure (for example, type of cross-linking agent, distance between cross-linking points (molecular weight between cross-linking points), By adjusting the crosslink density) and the like, the effect of the embodiment of the present invention (for example, durability in a high temperature and high humidity environment, suppression of decolorization when applied to an organic EL display device) can be made more remarkable. can.

The thickness of the first pressure-sensitive adhesive layer is preferably 2 μm to 30 μm, more preferably 3 μm to 25 μm, and further preferably 5 μm to 20 μm. The thickness of the second pressure-sensitive adhesive layer is preferably 10 μm to 50 μm, more preferably 15 μm to 40 μm, and even more preferably 15 μm to 30 μm. When the thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is within such a range, the durability in a high-temperature and high-humidity environment is achieved by a synergistic effect with the effect of the configuration of the protective layer and the retardation layer. It is possible to realize a polarizing plate with a retardation layer and an adhesive layer, which is excellent in quality and whose decolorization is remarkably suppressed when applied to an organic EL display device.

The solubility of the first pressure-sensitive adhesive layer (substantially the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer) in ethyl acetate at 25 ° C. is preferably 2 g / 100 g to 70 g / 100 g, more preferably 10 g. / 100 g to 60 g / 100 g, more preferably 15 g / 100 g to 60 g / 100 g.

The molar extinction coefficient of the first pressure-sensitive adhesive layer at a wavelength of 380 nm is preferably 400 L / (mol · cm) or more, more preferably 500 L / (mol · cm) or more, and even more preferably 600 L / (mol · cm). cm) or more. On the other hand, the molar extinction coefficient is preferably 1500 L / (mol · cm) or less. When the molar extinction coefficient is in such a range, the adverse effect of the conductive agent can be reduced, and excellent durability can be realized in a high temperature and high humidity environment. The molar extinction coefficient is a value obtained by the following formula.
Molar extinction coefficient = A / (c × l)
(In the formula, A represents the absorbance, c represents the molar concentration (mol / L), and l represents the cell thickness (cm).)

The gel fraction of the first pressure-sensitive adhesive layer is preferably 60% or more, more preferably 60% to 90%, and further preferably 78% to 90%. When the gel fraction is in such a range, foaming and peeling can be suppressed in a high temperature and high humidity environment, and deterioration of the appearance can be suppressed. The gel fraction is determined by (dry weight after immersion / dry weight before immersion) × 100 when the crosslinked pressure-sensitive adhesive is immersed in a predetermined solvent (for example, ethyl acetate) for 6 days and then dried.

Hereinafter, the constituent material (adhesive composition) will be described with the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer collectively as a pressure-sensitive adhesive layer.

D-2. Constituent materials for the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer D-2-1. The base polymer pressure-sensitive adhesive layer is typically formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer, a urethane-based polymer, a silicone-based polymer or a rubber-based polymer as a base polymer. When a (meth) acrylic polymer is used as the base polymer, the pressure-sensitive adhesive layer is formed from, for example, a pressure-sensitive adhesive composition containing the (meth) acrylic polymer (A). The (meth) acrylic polymer (A) contains an alkyl (meth) acrylate as a main component.

<(Meta) acrylic polymer (A)>
As described above, the (meth) acrylic polymer (A) contains an alkyl (meth) acrylate as a main component. The alkyl (meth) acrylate is preferably 50% by weight or more, and the alkyl (meth) acrylate is preferably 50% by weight or more in all the monomer components forming the (meth) acrylic polymer (A) from the viewpoint of improving the adhesiveness of the pressure-sensitive adhesive layer. ) It can be arbitrarily set as the rest of the monomer other than acrylate. In addition, (meth) acrylate means acrylate and / or methacrylate.

Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer (A) include linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group and a decyl group. , Isodecyl group, dodecyl group, isomiristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like. Alkyl (meth) acrylates can be used alone or in combination. The average carbon number of the alkyl group is preferably 3 to 10, and more preferably 3 to 6.

The (meth) acrylic polymer (A) contains acrylic acid as a monomer component as described above. As described above, the acrylic acid content in the monomer component is preferably 0.1% by weight to 10% by weight, more preferably 0.2% by weight to 8% by weight, still more preferably 0.2% by weight. % To 6% by weight.

The (meth) acrylic polymer (A) may contain a copolymerization monomer such as a carboxyl group-containing monomer (a1) and a hydroxyl group-containing monomer (a2) other than acrylic acid. The copolymerizable monomers can be used alone or in combination.

The carboxyl group-containing monomer (a1) is a compound containing a carboxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

The hydroxyl group-containing monomer (a2) is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group and a vinyl group. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl ( Examples thereof include hydroxyalkyl (meth) acrylates such as 10-hydroxydecyl (meth) acrylates and 12-hydroxylauryl (meth) acrylates; (4-hydroxymethylcyclohexyl) -methyl acrylates and the like. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable from the viewpoint of improving the durability of the pressure-sensitive adhesive layer.

When the hydroxyl group-containing monomer (a2) is used as the monomer component, the content of the hydroxyl group-containing monomer (a2) is usually 0.01% by weight in all the monomer components forming the (meth) acrylic polymer (A). It is 10% by weight or less, more preferably 0.05% by weight to 3% by weight.

Another copolymerization monomer (a3) may be further used as the monomer component. The other copolymerizable monomer (a3) has a polymerizable functional group having an unsaturated double bond such as, for example, a (meth) acryloyl group or a vinyl group. By using the other copolymerization monomer (a3), the adhesiveness and heat resistance of the pressure-sensitive adhesive layer can be improved. The other copolymerization monomer (a3) can be used alone or in combination.

By using an amino group-containing monomer and an amide group-containing monomer as the other copolymerization monomer (a3), the adhesion of the pressure-sensitive adhesive layer can be improved. The amino group-containing monomer is, for example, N, N-dimethylaminoethyl (meth) acrylate or N, N-dimethylaminopropyl (meth) acrylate. The amide group-containing monomer is, for example, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, N-methyl (meth) acrylamide, N-butyl ( Meta) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) ) Acrylamide-based monomers such as acrylamide and mercaptoethyl (meth) acrylamide; N-acrylloyl heterocyclic monomers such as N- (meth) acryloylmorpholine, N- (meth) acryloylpiperidin and N- (meth) acryloylpyrrolidine. It is an N-vinyl group-containing lactam-based monomer such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

In addition to the above, the other copolymerization monomer (a3) may be, for example, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, (meth). (Meta) acrylic acid alkoxyalkyl esters such as 3-methoxypropyl acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate; 2-( Cyclic-polymerizable monomer such as methyl acrylate); epoxy group-containing monomer such as (meth) glycidyl acrylate, (meth) methyl glycidyl acrylate; sulfonic acid group-containing monomer such as sodium vinyl sulfonate; phosphoric acid Group-containing monomer; (meth) acrylate having an alicyclic hydrocarbon group such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate; phenyl (meth) acrylate, (meth). ) (Meta) acrylic acid esters having aromatic hydrocarbon groups such as phenoxyethyl acrylate and benzyl (meth) acrylic acid; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene. Olefins or dienes such as ethylene, propylene, butadiene, isoprene, isobutylene; vinyl ethers such as vinylalkyl ethers; vinyl chloride can be used.

The content of the other copolymerization monomer (a3) in the (meth) acrylic polymer is preferably 20% by weight or less.

The (meth) acrylic polymer is, for example, a copolymer of butyl acrylate, acrylic acid, hydroxybutyl acrylate, hydroxyethyl acrylate and acryloylmorpholine, a copolymer of butyl acrylate, acrylic acid and hydroxyethyl acrylate, and butyl acrylate. It can be a copolymer of hydroxybutyl acrylate or a copolymer of butyl acrylate, acrylic acid, hydroxybutyl acrylate, N-vinylpyrrolidone and phenoxyethyl acrylate.

The weight average molecular weight Mw of the (meth) acrylic polymer (A) is, for example, 200,000 to 3 million, preferably 1 million to 2.5 million, and more preferably 1.2 million to 2.5 million. When the weight average molecular weight Mw is in such a range, a pressure-sensitive adhesive layer having excellent durability (particularly heat resistance) can be obtained. If the weight average molecular weight Mw exceeds 3 million, an increase in viscosity and / or gelation during polymer polymerization may occur.

D-2-2. Reactive functional group-containing silane coupling agent The pressure-sensitive adhesive composition can contain a reactive functional group-containing silane coupling agent. In the reactive functional group-containing silane coupling agent, the reactive functional group is typically a functional group other than the acid anhydride group. Examples of the functional group other than the acid anhydride group include an epoxy group, a mercapto group, an amino group, an isocyanate group, an isocyanurate group, a vinyl group, a styryl group, an acetoacetyl group, a ureido group, a thiourea group and a (meth) acrylic. Groups, heterocyclic groups, and combinations thereof can be mentioned. Reactive functional group-containing silane coupling agents can be used alone or in combination.

When the reactive functional group-containing silane coupling agent is blended in the pressure-sensitive adhesive composition, the blending amount of the reactive functional group-containing silane coupling agent is usually 100 parts by weight of the (meth) acrylic polymer (A). 0.001 part by weight or more and 5 parts by weight or less.

D-2-3. Cross-linking agent The pressure-sensitive adhesive composition can contain a cross-linking agent. As the cross-linking agent, an organic cross-linking agent, a polyfunctional metal chelate and the like can be used. Examples of the organic cross-linking agent include an isocyanate-based cross-linking agent, a peroxide-based cross-linking agent, an epoxy-based cross-linking agent, and an imine-based cross-linking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated to an organic compound. When the pressure-sensitive adhesive composition is a radiation-curable type, a polyfunctional monomer can be used as a cross-linking agent. Crosslinkers can be used alone or in combination.

When the cross-linking agent is blended in the pressure-sensitive adhesive composition, the blending amount of the cross-linking agent is usually 0.01 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer (A).

When the isocyanate-based cross-linking agent is blended in the pressure-sensitive adhesive composition, the blending amount of the isocyanate-based cross-linking agent is usually 0.01 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer.

D-2-4. Conductive Agent In the embodiment of the present invention, the pressure-sensitive adhesive layer (substantially, the pressure-sensitive adhesive composition) contains a conductive agent as described above. As described above, the conductive agent may be contained in the first pressure-sensitive adhesive layer or may be contained in the second pressure-sensitive adhesive layer. The conductive agent is preferably contained in the first pressure-sensitive adhesive layer. The conductive agent content in the pressure-sensitive adhesive layer is as described in the above item A.

The conductive agent is an inorganic cationic salt as described above. The inorganic cation salt is specifically an inorganic cation-anion salt. Typical examples of the cation constituting the cation portion of the inorganic cation salt include alkali metal ions. Specific examples include lithium ion, sodium ion, and potassium ion. Lithium ion is preferred. Therefore, the preferred inorganic cationic salt is a lithium salt.

Examples of the anion constituting the anion portion of the inorganic cation salts, for ^{^{^{_{^{example, Cl -, Br -, I}}}}} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, _{^{_{^{CH 3 COO -, CF 3 COO}}}} -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 3 C -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 -, (CN _{^{_{_{) 2 N -, C 4 F}}}} 9 SO 3 -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, and, below General formulas (1) to (4)
_{_{(1) :( C n F 2n}} + 1 SO 2) 2 N - (n is an integer of from 1 to 10),
_{_{_{(2): CF 2 (C}}} m F 2m SO 2) 2 N - (m is an integer of from 1 to 10),
^{_{_{(3): - O 3 S}}} (CF 2) l SO 3 - (l is an integer of from 1 to 10),
_{_{_{^{(4) :( C p F 2p}}}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
Examples thereof include anions represented by. Fluorine-containing anions are preferred, and fluorine-containing imide anions are more preferred.

Examples of the fluorine-containing imide anion include an imide anion having a perfluoroalkyl group. Specific examples include the above (CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ and the general formulas (1), (2) and (4).
_{_{(1) :( C n F 2n}} + 1 SO 2) 2 N - (n is an integer of from 1 to 10),
_{_{_{(2): CF 2 (C}}} m F 2m SO 2) 2 N - (m is an integer of from 1 to 10),
_{_{_{^{(4) :( C p F 2p}}}} + 1 SO 2) N - (C q F 2q + 1 SO 2), (p, q is an integer of 1 to 10),
Examples thereof include anions represented by. It is preferably a (perfluoroalkylsulfonyl) imide represented by the general formula (1) such as _{(CF 3} SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ _{, and more preferably (CF 3).} SO ₂₎ ₂ N ^- bis represented by (trifluoromethanesulfonyl) imide. Therefore, a preferred inorganic cationic salt that can be used in embodiments of the present invention is lithium bis (trifluoromethanesulfonyl) imide.

The conductive agent may further contain an organic cation salt, if necessary. By using the inorganic cation salt in combination with the organic cation salt, bleed-out of the inorganic cation salt can be suppressed.

Specifically, the organic cation salt is an organic cation-anion salt. Typical examples of the cation constituting the cation portion of the organic cation salt include organic onium in which onium ions are formed by substitution with an organic group. Examples of onium in organic onium include nitrogen-containing onium, sulfur-containing onium, and phosphorus-containing onium. Nitrogen-containing onium and sulfur-containing onium are preferable. As the nitrogen-containing onium, ammonium cation, piperidinium cation, pyrrolidinium cation, pyridinium cation, cation having pyrrolin skeleton, cation having pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, Examples thereof include pyrazolium cations and pyrazolinium cations. Ammonium cations, piperidinium cations, and pyrrolidinium cations are preferable, and pyrrolidinium cations are more preferable. Examples of the sulfur-containing onium include a sulfonium cation. Examples of the phosphorium-containing cation include a phosphonium cation. Examples of the organic group in organic onium include an alkyl group, an alkoxyl group, and an alkenyl group. Specific examples of preferable organic onium include tetraalkylammonium cations, alkylpiperidinium cations, and alkylpyrrolidinium cations. More preferably, it is an ethylmethylpyrrolidinium cation. The anions constituting the anion portion of the organic cation salt are as described with respect to the anions constituting the anion portion of the inorganic cation. Therefore, the preferred organic cation salt that can be used in the embodiments of the present invention is a pyrrolidinium salt, more preferably an ethylmethylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

D-2-5. The radical generator pressure-sensitive adhesive layer (substantially, the pressure-sensitive adhesive composition) may contain a radical generator. Examples of the radical generator include those that generate radicals by irradiation with visible light or ultraviolet rays having a wavelength shorter than 450 nm. Specific examples include hydroxyketones, benzyldimethylketals, aminoketones, acylphosphine oxides, benzophenones, and trichloromethyl group-containing triazine derivatives. The radical generator may be used alone or in combination of two or more. The radical generator can be a peroxide-based cross-linking agent. The radical generator is preferably 0.01 parts by weight to 2 parts by weight, more preferably 0.01 parts by weight to 1 part by weight, based on 100 parts by weight of the base polymer ((meth) acrylic polymer (A)). Can be used in proportions. Within such a range, it is easy to adjust workability, cross-linking stability and the like.

D-2-6. Additives The pressure-sensitive adhesive composition may contain (meth) acrylic oligomers and / or ionic compounds. Further, the pressure-sensitive adhesive composition may contain an additive. Specific examples of additives include powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antiaging agents, light stabilizers, and polymerization. Examples include banned agents, inorganic or organic fillers, metal powders, particles and foils. Further, a redox system to which a reducing agent is added may be adopted within a controllable range. The type, number, combination, content, etc. of additives can be appropriately set according to the purpose. The content of the additive is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and further preferably 1 part by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer (A). be.

E. Image display device The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer according to the above items A to D can be applied to an organic EL display device. Therefore, an embodiment of the present invention includes an organic EL display device using such a retardation layer and a polarizing plate with an adhesive layer. The organic EL display device according to the embodiment of the present invention includes the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer according to the above items A to D on the visible side thereof. The retardation layer and the polarizing plate with the pressure-sensitive adhesive layer are laminated so that the retardation layer is on the organic EL cell side (the polarizing plate is on the visual recognition side). In one embodiment, the organic EL display device has a curved shape (substantially a curved display screen) and / or is bendable or bendable. As described above, when the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer is applied to the organic EL display device, the present inventors have a phase difference due to ammonia (substantially ammonium ion) generated from the organic EL panel. A new problem of decolorization of the layer and the polarizing plate with the pressure-sensitive adhesive was discovered, and the problem was solved by the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer according to the above items A to D. That is, in the organic EL display device, the effect of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer according to the embodiment of the present invention is remarkable.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic is as follows. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are based on weight.
(1) Thickness The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name “MCPD-3000”). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu, product name “KC-351C”).
(2) Single transmittance and degree of polarization The polarizing plates used in the Examples and Comparative Examples were measured with an ultraviolet-visible spectrophotometer (“LPF-2000” manufactured by Otsuka Denshi Co., Ltd.), and the single transmittance Ts and parallel transmittance were measured. Tp and orthogonal transmittance Tc were defined as Ts, Tp and Tc of the spectrometer, respectively. These Ts, Tp and Tc are Y values measured by the JIS Z8701 two-degree visual field (C light source) and corrected for luminosity factor. From the obtained Tp and Tc, the degree of polarization P was determined by the following formula.
Polarization degree P (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100
(3) Moisture permeability Measured according to JIS Z 0208. Specifically, the protective layer or the retardation layer (the film constituting the layer) used in Examples and Comparative Examples was cut out in a circle of 10 cmΦ and used as a measurement sample. The moisture permeability of this measurement sample was measured using "MOCON" manufactured by Hitachi, Ltd. under the test conditions of 40 ° C. and 92% RH.
(4) Ammonia decolorization test 10 g of a 10% aqueous ammonia solution was placed in a glass bottle (cylindrical shape having a diameter of 30 mm and a depth of 50 mm). At this time, the distance from the liquid surface of the aqueous ammonia solution to the mouth (upper end) of the glass bottle was about 30 mm. The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 15 mm × 15 mm and used as a measurement sample. The measurement sample was attached to the edge of the mouth of the glass bottle via the second pressure-sensitive adhesive layer so that the mouth of the glass bottle was completely covered with this measurement sample and steam did not leak from the gap. The glass bottle covered with the measurement sample was heated at 60 ° C. for 3 hours. The simple substance transmittance before heating of the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer (substantially, the polarizing element) is Ts ₀ , and the simple substance transmittance after heating is Ts ₃ , and the formula: ΔTs = Ts ₃ _{-Ts 0.} ΔTs was calculated from. The smaller ΔTs, the more the decolorization due to ammonia is suppressed.
(5) Durability The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 300 mm × 220 mm, and a non-alkali glass plate was passed through a second pressure-sensitive adhesive layer using a laminator. (Made by Corning, trade name "EAGLE XG", thickness 70 μm). Then, it was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes, and the retardation layer and the polarizing plate with the pressure-sensitive adhesive layer were completely adhered to the non-alkali glass to prepare a measurement sample. After subjecting this measurement sample to a treatment (heating test) for 500 hours in an atmosphere of 85 ° C. and a treatment (humidification test) for 500 hours in an atmosphere of 65 ° C./95% RH, the retardation layer and adhesion The appearance between the polarizing plate with the agent layer and the glass was visually evaluated according to the following criteria.
Excellent: No change in appearance such as foaming or peeling Good: Slight peeling or foaming on the edges, but no practical problem Acceptable: Peeling or foaming on the edges, but special use If not, there is no problem in practical use. Defective: There is significant peeling at the end, and there is a problem in practical use.

[Manufacturing Example 1: Fabrication of Polarizing Plate]
(Making a polarizing element)
As the thermoplastic resin base material, an amorphous isophthal copolymer polyethylene terephthalate film (thickness: 100 μm) having a long shape, a water absorption rate of 0.75%, and a Tg of about 75 ° C. was used. One side of the resin substrate was corona-treated.
100 weight of PVA-based resin in which polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z410") are mixed at a ratio of 9: 1. A PVA aqueous solution (coating solution) was prepared by dissolving 13 parts by weight of potassium iodide in water.
The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 μm, and a laminate was prepared.
The obtained laminate was stretched 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, in a dyeing bath having a liquid temperature of 30 ° C. (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1: 7 with respect to 100 parts by weight of water), the polarizing film finally obtained is charged. It was immersed for 60 seconds while adjusting the concentration so that the simple substance transmittance (Ts) was 43.0% (staining treatment).
Then, it was immersed in a cross-linked bath having a liquid temperature of 40 ° C. (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4.0% by weight, potassium iodide 5.0% by weight) having a liquid temperature of 70 ° C., the rolls having different peripheral speeds are subjected to the longitudinal direction (longitudinal direction). ) Was uniaxially stretched so that the total stretch ratio was 5.5 times (underwater stretching treatment).
Then, the laminate was immersed in a washing bath having a liquid temperature of 20 ° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
Then, while drying in an oven kept at 90 ° C., it was brought into contact with a heating roll made of SUS whose surface temperature was kept at 75 ° C. for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the laminated body by the drying shrinkage treatment was 5.2%.
In this way, a polarizing element having a thickness of 5 μm was formed on the resin substrate.

(Preparation of polarizing plate)
An HC-COP film was attached to the surface of the polarizing element of the resin substrate / polarizing element laminate obtained above via an ultraviolet curable adhesive. Specifically, the curable adhesive was coated so as to have a thickness of 1.0 μm, and bonded using a roll machine. Then, UV light was irradiated from the HC-COP film side to cure the adhesive. The HC-COP film is a film in which an HC layer (thickness 2 μm) is formed on a cycloolefin resin (COP) film (thickness 25 μm), and the COP film is bonded so as to be on the polarizing element side. Moisture permeability of the HC-COP film was 17g ^/ m 2 · 24h.

[Manufacturing Example 2: Fabrication of Polarizing Plate]
Polarized light having a visible side protective layer (acrylic film) / polarizing element in the same manner as in Production Example 1 except that an acrylic film (thickness 20 μm) was used instead of the HC-COP film as the visible side protective layer. A plate P2 was obtained. Moisture permeability of acrylic film was 146g ^/ m 2 · 24h.

[Manufacturing Example 3: Fabrication of Polarizing Plate]
A polarizing plate P3 having a visible side protective layer (HC-TAC film) / polarizing element in the same manner as in Production Example 1 except that an HC-TAC film is used instead of the HC-COP film as the visible side protective layer. Got The HC-TAC film is a film in which a hard coat (HC) layer (thickness 7 μm) is formed on a triacetyl cellulose (TAC) film (thickness 25 μm), and the TAC film is attached so as to be on the stator side. I matched it. Moisture permeability of the HC-TAC film was 427g ^/ m 2 · 24h.

[Manufacturing Example 4: Fabrication of a retardation film constituting a retardation layer]
(Polyester carbonate-based resin polymerization)
Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. Bis [9- (2-phenoxycarbonylethyl) fluorene-9-yl] 29.60 parts (0.046 mol) of methane, 29.21 parts (0.200 mol) of isosorbide (ISB), 42.28 parts of spiroglycol (SPG) part (0.139 mol), were charged diphenyl carbonate (DPC) 63.77 parts (0.298 mol) and 1.19 × ^{10 -2} parts of calcium acetate monohydrate as a catalyst (6.78 × ¹⁰ -5 mol) is. After the inside of the reactor was replaced with nitrogen under reduced pressure, heating was performed with a heat medium, and stirring was started when the internal temperature reached 100 ° C. The internal temperature was brought to 220 ° C. 40 minutes after the start of the temperature rise, and the depressurization was started at the same time as controlling to maintain this temperature, and the temperature was 13.3 kPa 90 minutes after reaching 220 ° C. The phenol vapor produced by the polymerization reaction was guided to a reflux condenser at 100 ° C., the monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the non-condensed phenol vapor was guided to a condenser at 45 ° C. for recovery. Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Then, the temperature rise and depressurization in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Then, the polymerization was allowed to proceed until the stirring power became a predetermined value. When the predetermined power was reached, nitrogen was introduced into the reactor to repressurize, the produced polyester carbonate-based resin was extruded into water, and the strands were cut to obtain pellets.

(Making a retardation film)
After vacuum-drying the obtained polyester carbonate-based resin (pellet) at 80 ° C. for 5 hours, a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250 ° C.), T-die (width 200 mm, set temperature: 250). A long resin film having a thickness of 135 μm was prepared by using a film forming apparatus equipped with a chill roll (set temperature: 120 to 130 ° C.) and a winder. The obtained long resin film was stretched in the width direction at a stretching temperature of 133 ° C. and a stretching ratio of 2.8 times to obtain a retardation film I having a thickness of 47 μm. The Re (550) of the obtained retardation film was 141 nm, the Re (450) / Re (550) was 0.82, and the Nz coefficient was 1.12. Further, the moisture permeability of the obtained retardation film was 75g ^/ m 2 · 24h.

[Production Example 5: Preparation of Adhesive Base Polymer]
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler contains 76.9 parts of butyl acrylate, 18 parts of benzyl acrylate, 5 parts of acrylic acid, and 0.1 part of 4-hydroxybutyl acrylate. A mixture of monomers was charged. Further, 0.1 part of 2,2'-azobisisobutyronitrile was charged to 100 parts of this monomer mixture together with 100 parts of ethyl acetate as a polymerization initiator, and nitrogen gas was introduced with gentle stirring to introduce nitrogen. After the substitution, the liquid temperature in the flask was maintained at around 55 ° C. and the polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer (base polymer A) having a weight average molecular weight (Mw) of 2 million.

[Production Example 6: Preparation of Adhesive Base Polymer]
Similar to Production Example 5, acrylic-based Mw 2.5 million, except that a monomer mixture containing 91.5 parts of butyl acrylate, 3 parts of acrylic acid, 0.5 part of 4-hydroxybutyl acrylate and 5 parts of acryloyl morpholine was used. A solution of the polymer (base polymer B) was prepared.

[Production Example 7: Preparation of Adhesive Base Polymer]
A solution of an acrylic polymer (base polymer C) having a Mw of 1.6 million was prepared in the same manner as in Production Example 5 except that a monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was used.

[Production Example 8: Preparation of Adhesive Base Polymer]
Production Example 5 except that a monomer mixture containing 89.3 parts of butyl acrylate, 0.2 parts of acrylic acid, 0.5 parts of 4-hydroxybutyl acrylate, 2 parts of N-vinylpyrrolidone and 8 parts of methyl methacrylate was used. Similarly, a solution of an acrylic polymer (base polymer D) having Mw 1.6 million was prepared.

[Production Example 9: Preparation of Adhesive Base Polymer]
Similar to Production Example 5, an acrylic polymer (base polymer E) having a Mw of 2.3 million was used, except that a monomer mixture containing 94.9 parts of butyl acrylate, 5 parts of acrylic acid and 0.1 part of hydroxyethyl acrylate was used. A solution was prepared.

[Production Example 10: Preparation of Adhesive Composition]
A radical generator, a cross-linking agent, and a silane coupling agent are added to 100 parts of each of the base polymers A to E obtained in Production Examples 5 to 9 in the proportions shown in Table 1, and a pressure-sensitive adhesive composition (adhesive agent) is added. ) Was prepared. The names, abbreviations, etc. in Table 1 are as follows.
"BA": Butyl acrylate "AA": Acrylic acid "4HBA": 4-Hydroxybutyl acrylate "HEA": Hydroxyethyl acrylate "ACMO": Acryloyl morpholine "NVP": N-vinylpyrrolidone "MMA": Methyl methacrylate "BPO"": Benzoyl peroxide" C / L ": Trimethylolpropane / Tolylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name" Coronate L ")
"D110N": Trimethylolpropane / xylylene diisocyanate adduct (manufactured by Mitsui Chemicals, trade name "Takenate D110N")
"X-41-1056": Alkoxy-containing organopolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)
"KBM403": Epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Example 1]
A pressure-sensitive adhesive layer having a thickness of 20 μm was formed from the pressure-sensitive adhesive composition A shown in Table 1 to form a first pressure-sensitive adhesive layer. Further, a pressure-sensitive adhesive layer having a thickness of 20 μm was formed from the pressure-sensitive adhesive composition E to form a second pressure-sensitive adhesive layer. The pressure-sensitive adhesive composition A contained a conductive agent in the proportion shown in Table 2. The retardation film I obtained in Production Example 4 is attached to the surface of the polarizing element of the polarizing plate P1 obtained in Production Example 1 via the first pressure-sensitive adhesive layer, and further, the retardation film I is attached to the surface of the retardation film. The pressure-sensitive adhesive layer of 2 was provided. In this way, the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer of this example was produced. The obtained retardation layer and the polarizing plate with the pressure-sensitive adhesive layer were subjected to the evaluations of (4) and (5) above. The results are shown in Table 2. Table 2 also shows the gel fractions of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer.

[Examples 2 to 9, Comparative Examples 1 to 6, and Reference Example 1]
The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are formed by the composition, thickness and gel fraction of the conductive agent shown in Table 2, and the polarizing plate, the retardation film, the first pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer shown in Table 2 are formed. A retardation layer and a polarizing plate with a pressure-sensitive adhesive layer were produced by combining the second pressure-sensitive adhesive layers. The obtained retardation layer and the polarizing plate with the pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 2. The names, abbreviations, etc. in Table 2 are as follows.
"Li-TFSI": Lithium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Electronics Co., Ltd.)
"AS100": 1-ethyl-3-methylimidazolium bisfluorosulfonylimide (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)

[evaluation]
As is clear from Table 2, according to the embodiment of the present invention, the change in the single transmittance is small (that is, less decolorization) even when exposed to ammonia, and the durability is excellent in a high temperature and high humidity environment. Further, it is possible to obtain a retardation layer and a polarizing plate with a pressure-sensitive adhesive layer (specifically, peeling of the pressure-sensitive adhesive layer and bubbles are suppressed). Further, as is clear from Reference Example 1, it was found that the effect of containing the conductive agent and acrylic acid in the pressure-sensitive adhesive layer is an effect obtained in a configuration in which the moisture permeability of the visible side protective layer of the polarizing plate is small (). However, it does not deny that the pressure-sensitive adhesive layer contains a conductive agent and acrylic acid in a configuration in which the protective layer on the visible side of the polarizing plate has a large moisture permeability).

The polarizing plate with a retardation layer and an adhesive layer of the present invention is suitably used as an antireflection circular polarizing plate for an organic EL display device.

10 Polarizing plate 11 Polarizer 12 Protective layer 13 Protective layer 20 First pressure-sensitive adhesive layer 30 Phase difference layer 40 Second pressure-sensitive adhesive layer 100 Phase difference layer and polarizing plate with pressure-sensitive adhesive layer

Claims

A polarizing plate containing a polarizing element and a protective layer at least on the visible side of the polarizing element, and a retardation layer bonded to the opposite side of the polarizing plate via a first pressure-sensitive adhesive layer, and the same position. It has a second pressure-sensitive adhesive layer arranged as an outermost layer on the opposite side of the polarizing plate of the retardation layer.
The first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer contains acrylic acid as a monomer component of the base polymer and contains a conductive agent of an inorganic cationic salt.
The content of the conductive agent is 0.4 parts by weight to 12 parts by weight with respect to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
Polarizing plate with retardation layer and adhesive layer.
The polarizing plate with a retardation layer and an adhesive layer according to claim 1, wherein the acrylic acid content in the monomer component is 0.1% by weight to 10% by weight.
The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer according to claim 1 or 2, wherein the first pressure-sensitive adhesive layer contains acrylic acid as a monomer component of the base polymer and also contains a conductive agent of an inorganic cationic salt.
The polarizing plate with the retardation layer and the pressure-sensitive adhesive layer according to any one of claims 1 to 3, wherein the polarizing element and the retardation layer are bonded to each other via the first pressure-sensitive adhesive layer.
The polarizing plate with a retardation layer and an adhesive layer according to any one of claims 1 to 4, wherein the inorganic cationic salt is a lithium salt.
The moisture permeability of the viewer side protective layer is not more than 200g / m 2 · 24h, retardation layer and the adhesive layer-attached polarizing plate according to any one of claims 1 to 5.
An organic electroluminescence display device comprising the polarizing plate with the retardation layer and the pressure-sensitive adhesive layer according to any one of claims 1 to 6.