JP2021157146A - Circular polarization plate having barrier film and picture display unit using the same that can be rolled up - Google Patents

Abstract

To provide a circular polarization plate having a barrier film applicable to an extra-large picture display unit that can be rolled up.SOLUTION: A circular polarization plate 100 having a barrier film includes: a polarization plate 10 including a polarizer 11; a retardation layer 20; a barrier film 40 bonded to the retardation layer interposing a first adhesive layer; and a second adhesive layer 50 disposed as an outermost layer on an opposite side of the first adhesive layer 30 of the barrier film. The circular polarization plate can be rolled up in a direction orthogonal to an absorption axis direction of the polarizer. An angle formed by an absorption axis of the polarizer and a slow axis of the retardation layer is 40° to 50°. In the circular polarization plate having a barrier film, a dimensional change rate is 0.4% or less in the absorption axis direction of the polarizer after left standing at 80°C for 500 hours.SELECTED DRAWING: Figure 1

Description

The present invention relates to a circularly polarizing plate with a barrier film and a windable image display device using the circularly polarizing plate.

In recent years, image display devices represented by liquid crystal displays and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) have rapidly become widespread. A polarizing plate and a retardation plate are typically used in the image display device. Practically, a polarizing plate with a retardation layer (circular polarizing plate) in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1). In recent years, the possibility of bending, bending, folding, and winding of an image display device has been studied. For example, an ultra-large (for example, 55 inches or more) retractable television has been proposed, and a polarizing plate with a retardation layer (circular polarizing plate) applicable to such a retractable television is desired.

Japanese Patent No. 3325560

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a circularly polarizing plate with a barrier film that can be applied to an ultra-large rewindable image display device.

The circularly polarizing plate with a barrier film according to the embodiment of the present invention includes a polarizing plate containing a polarizer, a retardation layer, a barrier film bonded to the retardation layer via a first pressure-sensitive adhesive layer, and the like. It has a second pressure-sensitive adhesive layer provided as an outermost layer on the side opposite to the first pressure-sensitive adhesive layer of the barrier film, and can be wound in a direction orthogonal to the absorption axis direction of the polarizer. The angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 40 ° to 50 °. The circularly polarizing plate with a barrier film has a dimensional change rate of 0.4% or less in the absorption axis direction of the polarizer after being left at 80 ° C. for 500 hours.
In one embodiment, the moisture permeability of the barrier film is not more than ^{1.0 × 10 -2 g / m 2} / 24hr.
In one embodiment, the thickness of the barrier film is 100 μm or less.
In one embodiment, the thickness of the polarizer is 8 μm or less.
In one embodiment, the circularly polarizing plate with a barrier film can form a roll having a diameter of 20 mm to 120 mm by the winding.
In one embodiment, the circularly polarizing plate with a barrier film has a rectangular shape having a long side extending in the absorption axis direction of the polarizer and a short side extending in a direction orthogonal to the absorption axis direction, and has a long side. The length of the light is 1200 mm or more, and the length of the short side is 650 mm or more.
According to another aspect of the present invention, a windable image display device is provided. This image display device includes the above-mentioned circularly polarizing plate with a barrier film.
In one embodiment, the windable image display device is an organic electroluminescence display device.

According to the embodiment of the present invention, it is possible to realize a circularly polarizing plate with a barrier film that can be applied to an ultra-large rewindable image display device. This solves a new problem that did not exist in the past.

It is a schematic cross-sectional view of the circularly polarizing plate with a barrier film according to one Embodiment of this invention. It is a schematic perspective view explaining the relationship between the curl direction, the winding direction, and the absorption axis direction of a polarizing element of the circularly polarizing plate with a barrier film according to another embodiment of the present invention. (A) to (d) are schematic cross-sectional views for explaining a typical example of a barrier film used for a circularly polarizing plate with a barrier film according to an embodiment of the present 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 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-advance 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. 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 Circular Polarizing Plate with Barrier Film FIG. 1 is a schematic cross-sectional view of a circularly polarizing plate with a barrier film according to one embodiment of the present invention. The circularly polarizing plate 100 with a barrier film in the illustrated example includes a polarizing plate 10, a retardation layer 20, a barrier film 40 bonded to the retardation layer 20 via a first adhesive layer 30, and a barrier film 40. It has a second pressure-sensitive adhesive layer 50 provided as an outermost layer on the opposite side of the first pressure-sensitive adhesive layer 30. The polarizing plate 10 includes a polarizer 11, a first protective layer 12 arranged on one side of the polarizer 11, and a second protective layer 13 arranged on the other side of the polarizer 11. .. Depending on the purpose, one of the first protective layer 12 and the second protective layer 13 may be omitted. For example, if the retardation layer 20 can also function as a protective layer for the polarizer 11, the second protective layer 13 may be omitted.

The retardation layer 20 is typically composed of a stretched film of a resin film. The in-plane retardation Re (550) of the retardation layer 20 is typically 100 nm to 200 nm. The angle formed by the slow axis of the retardation layer 20 and the absorption axis of the polarizer 11 is typically 40 ° to 50 °. With such a configuration, an excellent circularly polarized light function can be obtained, and as a result, excellent antireflection characteristics can be obtained.

In the embodiment of the present invention, the circularly polarizing plate with a barrier film has a dimensional change rate of 0.4% or less in the absorption axis direction of the polarizer 11 after being left at 80 ° C. for 500 hours. As a result, curl of the polarizer in the absorption axis direction can be remarkably suppressed. With such a configuration, the following advantages can be obtained when the circularly polarizing plate with a barrier film is applied to an ultra-large and rewindable image display device (for example, a rewind-type television of 55 inches or more). Can be In the polarizing plate with a retardation layer applied to an ultra-large image display device, the polarizing plate with a retardation layer itself is an ultra-large size corresponding to the size and shape of the image display device. Such a super-large polarizing plate with a retardation layer has a long side in the absorption axis direction of the polarizer (long direction of the original roll) due to the size (substantially the width) of the original roll. It is cut out so as to be. As shown in FIG. 2, the polarizing plate with a retardation layer cut out in this way has a large curl in the absorption axis direction (long side direction) of the polarizer, which is the stretching direction of the original roll. Further, in the image display device that can be wound up, a resin film is used for the substrate so that the image display device can be wound up. Since the resin film has much higher permeability than glass, even if a conventional polarizing plate with a retardation layer is applied to a retractable image display device, the image is displayed by oxygen, moisture and / or water vapor in the air. The metal layer, wiring, etc. of the device may deteriorate. Therefore, when it is necessary to introduce a barrier film into the polarizing plate with a retardation layer, since the barrier film is thick, the distance between the polarizer and the display cell becomes large, which causes the curl to become larger. Here, the windable image display device is typically wound in the short side direction (direction orthogonal to the absorption axis direction) as shown in FIG. Then, since the winding direction and the curl direction are orthogonal to each other and the curl is large, the winding adversely affects the optical characteristics of the circularly polarizing plate with a barrier film, causes a problem in winding, and / or Winding itself may not be possible. These are issues that have been recognized for the first time when a circularly polarizing plate with a barrier film is applied to an ultra-large and windable image display device. According to the embodiment of the present invention, the above-mentioned new problems can be solved by controlling the dimensional change rate of the polarizer of the circularly polarizing plate with a barrier film in the absorption axis direction in a harsh environment. .. Such a dimensional change rate is a mechanical and / or viscoelastic property of the polarizing plate (polarizer and / or protective layer), the retardation layer, the barrier layer, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer. Can be achieved by optimizing. Details of these will be described later.

As shown in the above and FIG. 2, the circularly polarizing plate with a barrier film can be wound in a direction orthogonal to the absorption axis direction. According to the embodiment of the present invention, such winding is possible as described above. Further, with such a configuration, cracking of the barrier film at the time of winding can be prevented. In one embodiment, the circularly polarizing plate with a barrier film can form a roll having a diameter of 20 mm to 120 mm by such winding.

As described above, the circularly polarizing plate with a barrier film typically has a size and shape corresponding to an ultra-large image display device. For example, a circularly polarizing plate with a barrier film has a rectangular shape having a long side extending in the absorption axis direction of the polarizer and a short side extending in a direction orthogonal to the absorption axis direction. The length of the long side is preferably 1200 mm or more, more preferably 1400 mm or more, and further preferably 1700 mm or more. The upper limit of the length of the long side can be, for example, 2350 mm or less. The length of the short side is preferably 650 mm or more, more preferably 800 mm or more, and further preferably 950 mm or more. The upper limit of the length of the short side can be, for example, 1300 mm or less.

In one embodiment, the circularly polarizing plate with a barrier film may further have another retardation layer (not shown) between the retardation layer 20 and the second pressure-sensitive adhesive layer 50. Another retardation layer typically exhibits a relationship in which the refractive index characteristic is nz> nz = 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. Another retardation layer may be provided between the retardation layer 20 and the barrier film 40, or may be provided between the barrier film 40 and the second pressure-sensitive adhesive layer 50. For convenience, the retardation layer 20 may be referred to as a first retardation layer, and another retardation layer may be referred to as a second retardation layer.

The circularly polarizing plate with a barrier film may have an additional retardation layer (not shown). The additional retardation layer may be provided in combination with another retardation layer, or may be provided alone (ie, without providing another retardation layer). The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, and the like of the further retardation layer can be appropriately set according to the purpose.

Practically, it is preferable that a release film is temporarily attached to the surface of the second pressure-sensitive adhesive layer 50 until the circularly polarizing plate with a barrier film is used. By temporarily attaching the release film, the second pressure-sensitive adhesive layer can be protected and a roll of a circularly polarizing plate with a barrier film can be formed.

Hereinafter, the components of the circularly polarizing plate with a barrier film will be described in more detail.

B. Polarizing plate B-1. Polarizer As described above, the polarizing element 11 is composed of a PVA-based resin film containing a dichroic substance (typically, iodine or a dichroic dye). The dichroic substance is preferably iodine. The polarizer may be formed of a single-layer resin film or may be formed of a laminate of two or more layers.

Specific examples of the polarizer formed from the 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 properties, a polarizer 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. Stretching may be performed after the dyeing treatment or while dyeing. Alternatively, it may be stretched and then dyed. 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 the resin base material. 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 a protective film for the polarizer), or the resin base material is peeled off from the resin base material / polarizer laminate. Then, any suitable protective film according to the purpose may be laminated on the peeled surface. Details of the method for producing such a polarizer 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.

As the PVA-based resin forming the PVA-based resin film, any suitable resin can be adopted. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying the ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.9 mol%, and more preferably 99.0 mol% to 99.5 mol%. .. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the intended purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be determined according to JIS K 6726-1994.

The iodine concentration in the PVA-based resin film (polarizer) is, for example, 5.0% by weight to 12.0% by weight. The boric acid concentration in the PVA-based resin film is, for example, 12% by weight to 25% by weight.

The thickness of the polarizer is, for example, 12 μm or less, preferably 8 μm or less, more preferably 7 μm or less, still more preferably 6 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more, more preferably 2 μm or more.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizer (excluding the polyeneized portion) is preferably 40.0% to 46.0%, more preferably 41.0% to 45.0%. The degree of polarization of the polarizer (excluding the polyeneized portion) is preferably 99.9% or more, more preferably 99.95% or more, and further preferably 99.98% or more.

B-2. Protective Layer The first protective layer 12 and the second protective layer 13 are each formed of any suitable film that can be used as a protective layer 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. , Polyester-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, a vitreous polymer such as a siloxane-based polymer 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 circularly polarizing plate with a barrier film is typically arranged on the viewing side of the image display device as described later, and the first protective layer 12 is typically arranged on the viewing side. Therefore, the first protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and anti-glare treatment, if necessary. Further / or, if necessary, the first 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 imparted. (Giving an ultra-high phase difference) may be applied.

The thickness of the first protective layer is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm. When the surface treatment is applied, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

The second 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 second protective layer 13 may, in one embodiment, be a retardation layer having any suitable retardation value. In this case, the in-plane retardation Re (550) of the retardation layer is, for example, 110 nm to 150 nm. The thickness of the second protective layer is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm, and even more preferably 10 μm to 60 μm.

C. First Phase Difference Layer The first phase difference layer 20 may have any suitable optical and / or mechanical properties depending on the intended purpose. The first retardation layer 20 typically has a slow axis. In one embodiment, the angle θ formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is 40 ° to 50 °, preferably 42 ° to 48 °, as described above. It is more preferably about 45 °. If the angle θ is in such a range, by using a λ / 4 plate as the first retardation layer as described later, very excellent circularly polarized light characteristics (as a result, very excellent antireflection characteristics). A circularly polarizing plate with a barrier film having the above can be obtained.

The first retardation layer preferably has a refractive index characteristic of nx> ny ≧ nz. The first retardation layer is typically provided to impart antireflection properties 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 first retardation layer is preferably 100 nm to 200 nm, more preferably 110 nm to 170 nm, and even more preferably 130 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 may be satisfied as long as the effect of the present invention is not impaired.

The Nz coefficient of the first retardation layer 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. It is 3. By satisfying such a relationship, a very excellent reflected hue can be achieved when the obtained circularly polarizing plate with a barrier film is used in an image display device.

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It may be shown, or may show a flat wavelength dispersion characteristic in which the phase difference value hardly changes with the wavelength of the measurement light. In one embodiment, the first retardation layer exhibits inverse dispersion wavelength characteristics. In this case, the 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 absolute value of the photoelastic coefficient of the first retardation layer is preferably 2 × 10 ^-11 m ² / N or less, more preferably 2.0 × 10 ^-13 m ² / N to 1.5 ^{× 10 -11.} m ² / N, more preferably from ^{1.0 × 10 -12 m 2 /N~1.2×10 -11} m 2 / 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 first retardation layer is typically composed of a stretched film of a resin film. The thickness of the first retardation layer is preferably 70 μm or less, preferably 45 μm to 60 μm. When the thickness of the first retardation layer is within such a range, it is possible to satisfactorily adjust the curl at the time of bonding while satisfactorily suppressing the curl at the time of heating.

The first retardation layer 20 may be made of any suitable resin film that can satisfy the above characteristics. Typical examples of such resins are polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, and polyamide resins. , Polyethylene resin, polyether resin, polystyrene resin, acrylic resin and the like. These resins may be used alone or in combination (eg, blending, copolymerizing). When the first retardation layer is composed of a resin film exhibiting inverse dispersion wavelength characteristics, a polycarbonate resin or a polyester carbonate resin (hereinafter, may be simply referred to as a polycarbonate resin) can be preferably used.

As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as the effects of the present invention can be obtained. For example, a polycarbonate resin contains 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-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. Includes 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. Details of the polycarbonate resin that can be suitably used in the present invention are, for example, JP-A-2014-10291, JP-A-2014-26266, JP-A-2015-212816, JP-A-2015-212817. , 2015-21218, and the description is incorporated herein by reference.

The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 150 ° C. or lower, and 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, dimensional changes may occur after film molding, and the image quality of the obtained organic EL panel may be deteriorated. 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 an Ubbelohde viscous 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 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 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 the product names "Pure Ace WR-S", "Pure Ace WR-W", "Pure Ace WR-M" manufactured by Teijin Limited, and the product name "NRF" manufactured by Nitto Denko. Be done.

The first retardation layer 20 is 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, 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 first 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. 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 circularly polarizing plate with a barrier film. As described above, the angle θ is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and even more preferably about 45 °.

Examples of the stretching machine used for diagonal stretching include a tenter type stretching machine capable of applying a feeding force, a pulling force, or a pulling force at different speeds in the horizontal and / or vertical directions. The tenter type stretching machine includes a horizontal uniaxial stretching machine, a simultaneous biaxial stretching machine, and the like, but any suitable stretching machine can be used as long as the long resin film can be continuously and diagonally stretched.

By appropriately controlling the left and right velocities in the stretching machine, a retardation layer having the desired in-plane phase difference and having a slow phase axis in the desired direction (substantially long). (Phase difference film) can be obtained.

The stretching temperature of the film can change depending on the in-plane retardation value and thickness desired for the retardation layer, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably Tg-30 ° C to Tg + 30 ° C, more preferably Tg-15 ° C to Tg + 15 ° C, and most preferably Tg-10 ° C to Tg + 10 ° C. By stretching at such a temperature, a first retardation layer having appropriate characteristics in the present invention can be obtained. Tg is the glass transition temperature of the constituent material of the film.

D. Second Phase Difference Layer The second phase difference layer can be a so-called positive C plate having a refractive index characteristic of nz> nz = ny as described above. By using the positive C plate as the second 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. In this case, the retardation Rth (550) in the thickness direction of the second retardation layer is preferably −50 nm to −300 nm, more preferably −70 nm to −250 nm, still more preferably −90 nm to −200 nm, and particularly preferably. It is -100 nm to -180 nm. Here, "nx = ny" includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. That is, the in-plane retardation Re (550) of the second retardation layer can be less than 10 nm.

The second retardation layer with a refractive index characteristic of nz> nx = ny can be formed of any suitable material. The second retardation layer preferably consists of a film containing a liquid crystal material fixed in a homeotropic orientation. The liquid crystal material (liquid crystal compound) that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the retardation layer include the liquid crystal compounds described in [0020] to [0028] of JP-A-2002-333642 and the method for forming the retardation layer. In this case, the thickness of the second retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

E. Barrier film A barrier film typically has a barrier function against oxygen and / or water vapor. As described above, the windable image display device may have difficulty in winding on a glass substrate, and therefore a resin film can be used as the substrate. By providing a barrier film, when a circularly polarizing plate with a barrier film is applied to an image display device that can be wound up, deterioration of the metal layer, wiring, etc. of the image display device due to oxygen, moisture and / or water vapor in the air can be prevented. This can be prevented and the life of the function of the image display device can be extended. Water vapor permeability of the barrier film (moisture permeability) is preferably not more than ^{1.0 × 10 -2 g / m 2} / 24hr, more preferably be ^{5.0 × 10 -3 g / m 2} / 24hr or less , more preferably not more than ^{1.0 × 10 -3 g / m 2} / 24hr. As moisture permeability preferably small, its lower limit can be, for example, ^{1.0 × 10 -4 g / m 2} / 24hr. Moisture permeability can be measured by a JIS K7129 compliant measurement method in an atmosphere of 40 ° C. and 90% RH. The oxygen permeability of the barrier film is preferably 10 cm ³ / (m ² · day · atm) or less, more preferably 1 cm ³ / (m ² · day · atm) or less, and even more preferably 0. It is 1 cm ³ / (m ² · atm · day) or less. Oxygen permeability can be measured by a measurement method based on JIS K7126 in an atmosphere of 25 ° C. and 0% RH.

As long as the barrier film has the above-mentioned barrier function, any suitable configuration can be adopted. The barrier film is typically a laminated film having a resin film 41 and a barrier layer 42, as shown in FIG. 3A. Preferably, the resin film 41 may have barrier function, transparency and / or optical isotropic properties. Specific examples of such resins include cyclic olefin resins, polycarbonate resins, cellulosic resins, polyester resins, and acrylic resins. Preferably, it has a cyclic structure such as a cyclic olefin resin (for example, norbornene resin), a polyester resin (for example, polyethylene terephthalate (PET)), and an acrylic resin (for example, a lactone ring or a glutarimide ring in the main chain). Acrylic resin). These resins can have an excellent balance of barrier function, transparency and optical isotropic properties.

The barrier layer 42, for example, a metal deposited film, an oxide film of a metal, oxynitride film or a nitride film, metal foil, or oxide film (SiO 2) of silicon _oxide, nitride films (Si ₂ N ₂ O, SiON) or a nitride film (Si ₃ N ₄ ) can be mentioned. An oxide film of metal or silicon can be formed, for example, by sputtering. Examples of the metal of the metal vapor deposition film include In, Sn, Pb, Cu, Ag, and Ti. Examples of the metal oxide include ITO, IZO, AZO, SiO ₂ , MgO, SiO, SixOy, Al ₂ O ₃ , GeO, and TiO ₂ . Examples of the metal foil include aluminum foil, copper foil, and stainless steel foil.

A modified example of the structure of the barrier film will be briefly described with reference to FIGS. 3 (b) to 3 (d). As shown in FIG. 3B, the barrier film may have a first barrier layer 42 and a second barrier layer 43 on both sides of the resin film 41, respectively. The first barrier layer 42 and the second barrier layer 43 may be the same or different. Further, as shown in FIG. 3C, the barrier film may be one in which the two barrier films shown in FIG. 3A are bonded to each other via the adhesive layer 45. Further, the barrier film may further have organic layers 47 and 48, as shown in FIG. 3 (d). The organic layer may be provided for the purpose of preventing scratches on the barrier layer. The organic layer contains, for example, an acrylic resin. Either one of the organic layers 47 and 48 may be omitted.

As a further modification of the structure of the barrier film, a multilayer laminate having only a barrier layer can be mentioned. In this case, all the barrier layers constituting the multilayer laminate may be the same, some may be the same, or all may be different. The number of layers of the multilayer laminate can be appropriately set according to the purpose, the desired barrier function, and the like. The number of layers is preferably 2 to 10 layers, more preferably 3 to 7 layers, and further preferably 4 to 6 layers. Specific examples, SiO ₂ layer (80 nm) / SiON layer (40nm) / SiO ₂ layer (80 nm) / SiON layer (40nm) / SiO ₂ layer 5 layer laminate (80 nm) and the like.

The thickness of the barrier film is, for example, 0.2 μm to 100 μm, preferably 10 μm to 100 μm, more preferably 20 μm to 80 μm, and further preferably 30 μm to 60 μm. When the thickness of the barrier film is within such a range, the circularly polarizing plate with a barrier film can be formed on a roll having the desired diameter, and as a result, an image in which the circularly polarizing plate with a barrier film can be wound up. It can be suitably applied to a display device.

F. Storage modulus at 25 ° C. of the first adhesive layer and the first adhesive layer is, for example, 1.5 × ¹⁰ 5 (Pa) or less, preferably 1.0 × ¹⁰ 5 (Pa) or less, It is more preferably 5.0 × 10 ³ (Pa) to 9.0 × 10 ⁴ (Pa), and further preferably 1.0 × 10 ⁴ (Pa) to 8.5 × 10 ⁴ (Pa). When the storage elastic modulus of the first pressure-sensitive adhesive layer is within such a range, cracks in the polarizing plate can be remarkably suppressed even when a circularly polarizing plate with a barrier film is rolled.

As the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer, any suitable pressure-sensitive adhesive may be used as long as it has the above-mentioned characteristics. Typical examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive (acrylic pressure-sensitive adhesive composition). The acrylic pressure-sensitive adhesive composition typically contains a (meth) acrylic polymer as a main component (base polymer). The (meth) acrylic polymer can be contained in the pressure-sensitive adhesive composition in a proportion of, for example, 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more in the solid content of the pressure-sensitive adhesive composition. The (meth) acrylic polymer contains an alkyl (meth) acrylate as a main component as a monomer unit. In addition, (meth) acrylate means acrylate and / or methacrylate. Examples of the alkyl group of the alkyl (meth) acrylate include a linear or branched-chain alkyl group having 1 to 18 carbon atoms. The average number of carbon atoms of the alkyl group is preferably 3 to 9. In addition to alkyl (meth) acrylates, the monomers constituting the (meth) acrylic polymer include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth) acrylates, and heterocyclic ring-containing (meth) monomers. Examples thereof include comonomer such as acrylate. The acrylic pressure-sensitive adhesive composition may preferably contain a silane coupling agent and / or a cross-linking agent. Examples of the silane coupling agent include an epoxy group-containing silane coupling agent. Examples of the cross-linking agent include isocyanate-based cross-linking agents and peroxide-based cross-linking agents. The weight average molecular weight Mw of the base polymer in the pressure-sensitive adhesive composition is preferably 20000 or less, and more preferably 5000 to 1600000. Details of the first pressure-sensitive adhesive layer or the acrylic pressure-sensitive adhesive composition constituting the first pressure-sensitive adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2016-190996, and the description of the publication is referred to in the present specification. It is used as.

The thickness of the first pressure-sensitive adhesive layer is preferably 1 μm to 100 μm, more preferably 5 μm to 60 μm, and even more preferably 10 μm to 30 μm.

G. Second Adhesive Layer The second adhesive layer may be the same as or different from the first adhesive layer. In one embodiment, the storage elastic modulus of the second pressure-sensitive adhesive layer at 25 ° C. is greater than the storage elastic modulus of the first pressure-sensitive adhesive layer. With such a configuration, the strain of the barrier film can be reduced. In another embodiment, the storage elastic modulus of the second pressure-sensitive adhesive layer at 25 ° C. may be smaller than the storage elastic modulus of the first pressure-sensitive adhesive layer. As the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer, any suitable pressure-sensitive adhesive may be used depending on the purpose. As the pressure-sensitive adhesive, for example, the acrylic pressure-sensitive adhesive described for the first pressure-sensitive adhesive layer can be used. A second pressure-sensitive adhesive layer having a desired storage elastic modulus can be obtained by appropriately adjusting the type, number, combination, composition ratio, molecular weight of the base polymer, type of cross-linking agent, blending amount, etc. of the monomer components. ..

The thickness of the second pressure-sensitive adhesive layer is preferably 1 μm to 100 μm, more preferably 5 μm to 60 μm, and even more preferably 10 μm to 30 μm.

H. Image display device The circularly polarizing plate with a barrier film according to the above items A to G can be applied to an image display device. Therefore, the present invention includes an image display device using such a circularly polarizing plate with a barrier film. The image display device is typically rewindable. Typical examples of the image display device include a liquid crystal display device and an electroluminescence (EL) display device (for example, an organic EL display device and an inorganic EL display device). An organic EL display device is preferable. The image display device according to the embodiment of the present invention includes the circularly polarizing plate with a barrier film according to the above items A to G on the visual side thereof. The circularly polarizing plate with a barrier film is laminated so that the retardation layer is on the image display cell (for example, liquid crystal cell, organic EL cell, inorganic EL cell) side (so that the polarizer is on the visual recognition side). The image display device is, for example, 55 inches or more. The image display device typically has a rectangular shape, and the length of the long side is preferably 1200 mm or more, more preferably 1400 mm or more, and further preferably 1700 mm or more. The upper limit of the length of the long side can be, for example, 2350 mm or less. The length of the short side is preferably 650 mm or more, more preferably 800 mm or more, and further preferably 950 mm or more. The upper limit of the length of the short side can be, for example, 1300 mm or less.

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 Measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000").
(2) Dimensional change rate The circularly polarizing plate with a barrier film obtained in Examples and Comparative Examples was cut out to a size of 100 mm × 100 mm. At this time, it was cut out so that the absorption axis directions of the polarizers were in the directions of the two opposite sides. The cut out circularly polarizing plate with a barrier film was attached to a glass plate via an adhesive to prepare a test sample. The test sample was put into a heating oven maintained at 85 ° C. for 500 hours, and the dimensional change rate was calculated for each of the long side direction and the short side direction from the dimensions before and after heating by the following formula.
Dimensional change rate (%) = (dimensions after heating-dimensions before heating) / (dimensions before heating) x 100

[Production Example 1] Preparation of Adhesive Constituting First Adhesive Layer 99 parts of butyl acrylate, 4-hydroxybutyl acrylate in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. 1 part, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, nitrogen gas was introduced with gentle stirring to replace nitrogen, and then the liquid in the flask. The polymerization reaction was carried out for 8 hours while keeping the temperature at around 55 ° C. to prepare a solution of an acrylic polymer. 0.1 part of isocyanate cross-linking agent (Takenate D110N manufactured by Mitsui Takeda Chemical Co., Ltd., trimethylolpropane xylylene diisocyanate) and benzoyl peroxide (manufactured by Nippon Oil & Fats Co., Ltd.) with respect to 100 parts of the solid content of the obtained acrylic polymer solution. A solution of the acrylic pressure-sensitive adhesive composition was prepared by blending 0.1 part of niper BMT) and 0.2 part of γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403). Next, the solution of the acrylic pressure-sensitive adhesive composition was applied to one side of a polyethylene terephthalate film (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) treated with a silicone-based release agent, and applied at 150 ° C. for 3 minutes. Drying was performed to form an adhesive layer having a thickness of 20 μm on the surface of the separator film. The storage elastic modulus of the obtained pressure-sensitive adhesive was 8.2 × 10 ⁴ (Pa).

[Production Example 2] Preparation of Adhesive Constituting a Second Adhesive Layer In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 90.7 parts of butyl acrylate and N-acrylic acid 6 parts of morpholin, 3 parts of acrylic acid, 0.3 part of 2-hydroxybutyl acrylate, and 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with 100 g of ethyl acetate and gently stirred. After introducing nitrogen gas and substituting with nitrogen, the liquid temperature in the flask was maintained at around 55 ° C. and the polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution. 0.2 parts of isocyanate cross-linking agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd., Adduct of trimethylolpropane tolylene diisocyanate) and benzoyl peroxide (Japan) with respect to 100 parts of the solid content of the obtained acrylic polymer solution. An acrylic pressure-sensitive adhesive solution containing 0.3 part of Niper BMT manufactured by Yushi Co., Ltd. and 0.2 part of γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd .: KBM-403) was prepared. Next, the acrylic pressure-sensitive adhesive solution was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) subjected to silicone treatment, and the thickness of the pressure-sensitive adhesive layer after drying was 20 μm. And dried at 150 ° C. for 3 minutes to form an adhesive layer. The resulting storage modulus of the pressure-sensitive adhesive was 1.3 × ¹⁰ 5 (Pa).

[Example 1]
1. 1. Fabrication of Polarizer As a thermoplastic resin base material, an amorphous isophthal copolymer polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75 ° C. was used, and one side of the resin base material was treated with corona. Was given.
100 parts by weight of PVA-based resin in which polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimmer") 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 to prepare a laminate.
The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) 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. (an aqueous boric acid 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 polarizer finally obtained Immersion was carried out for 60 seconds while adjusting the concentration so that the simple substance transmittance (Ts) became a desired value (dyeing treatment).
Next, it was immersed in a cross-linked bath at a liquid temperature of 40 ° C. (an aqueous boric acid 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% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70 ° C., the total in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
Then, the laminate was immersed in a washing bath at 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 about 90 ° C., it was brought into contact with a heating roll made of SUS whose surface temperature was kept at about 75 ° C. (dry shrinkage treatment).
In this way, a polarizer having a thickness of about 5 μm was formed on the resin substrate, and a polarizing plate having a resin substrate / polarizer configuration was obtained.

2. Fabrication of Polarizing Plate An acrylic resin film (manufactured by Kaneka Corporation, product name "XR28-") is used as a first protective layer on the surface of the obtained polarizing element (the surface opposite to the resin base material) obtained above. HTX ”, thickness 45 μm) was bonded via an ultraviolet curable adhesive. Specifically, the curable adhesive was coated so as to have a total thickness of about 1.0 μm, and bonded using a roll machine. Then, UV light was irradiated from the side of the acrylic resin film to cure the adhesive. Next, the resin base material was peeled off to obtain a polarizing plate having an acrylic resin film (first protective layer) / polarizing element.

3. 3. Preparation of retardation film constituting the retardation layer 3-1. Polymerization of polyester carbonate-based resin 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) fluoren-9-yl] methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiroglycol (SPG) 42 .28 parts by mass (0.139 mol), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC) and 1.19 x 10-2 parts by mass (6.78 x 10-) of calcium acetate monohydrate as a catalyst. 5 mol) was charged. After substituting nitrogen under reduced pressure in the reactor, 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 adjusted to 13.3 kPa 90 minutes after reaching 220 ° C. The phenol vapor produced as a by-product of 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.

3-2. Preparation of retardation film After vacuum-drying the obtained polyester carbonate resin (pellets) 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 ° C.), chill roll (set temperature: 120 to 130 ° C.), and a film-forming device equipped with a winder was used to prepare a long resin film having a thickness of 135 μm. The obtained long resin film was stretched in the width direction at a stretching temperature of 133 ° C. and a stretching ratio of 2.2 times to obtain a retardation film having a thickness of 58 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.

4. Fabrication of circularly polarizing plate with barrier film 2. On the polarizer surface of the polarizing plate obtained in 3. above. The retardation film obtained in (1) was bonded via an acrylic pressure-sensitive adhesive (thickness: 5 μm). At this time, the absorption axis of the polarizer and the slow axis of the retardation film were bonded so as to form an angle of 45 °. In this way, a circularly polarizing plate with a barrier film having a polarizing plate / retardation layer configuration was obtained. Further, a barrier film was attached to the surface of the retardation layer via the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) of Production Example 1. The barrier film is a laminated film having a structure of a cyclic olefin resin (COP) film (50 μm) / organic layer (0.9 μm) / barrier layer (0.03 μm, _{sputter layer of SiO 2) / organic layer (0.9 μm).} Was used to bond the COP films so that they were on the retardation layer side. Further, the pressure-sensitive adhesive layer of Production Example 2 was provided on the surface of the organic layer of the barrier film. Then, it was cut into a predetermined size to obtain a circularly polarizing plate with a barrier film having a structure of a polarizing plate / a retardation layer / a first pressure-sensitive adhesive layer / a barrier film / a second pressure-sensitive adhesive layer. The size of the obtained circularly polarizing plate with a barrier film was 1716 mm (direction of the absorber in the absorption axis) × 980 mm (direction orthogonal to the direction of the absorption axis). The obtained circularly polarizing plate with a barrier film was used for evaluation of the dimensional change rate in (2) above. The results are shown in Table 1.

[Example 2]
A circularly polarizing plate with a barrier film was obtained in the same manner as in Example 1 except that a laminated film having a composition of COP film (40 μm) / barrier layer (0.03 μm, _{sputter layer of SiO 2) was used as the barrier film.} .. The obtained circularly polarizing plate with a barrier film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Example 3]
As a barrier film, COP film (15 μm) / barrier layer (0.03 μm, _{sputter layer of SiO 2} ) / adhesive layer (15 μm) / barrier layer (0.03 μm, _{sputter layer of SiO 2} ) / COP film (15 μm) A circularly polarizing plate with a barrier film was obtained in the same manner as in Example 1 except that a laminated film having a structure was used. The obtained circularly polarizing plate with a barrier film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
1. 1. Preparation of Polarizer A polyvinyl alcohol-based resin film having an average degree of polymerization of 2,400, a saponification degree of 99.9 mol%, and a thickness of 60 μm was prepared. The polyvinyl alcohol film was immersed in a swelling bath (water bath) at 20 ° C. for 30 seconds between rolls having different peripheral speed ratios and stretched 2.4 times in the transport direction while swelling (swelling step). Dyeing by immersing in a dyeing bath at 30 ° C. (an aqueous solution having an iodine concentration of 0.03% by weight and a potassium iodide concentration of 0.3% by weight) so that the single transmittance after final stretching becomes a desired value. While using the original polyvinyl alcohol film (polyvinyl alcohol film not stretched at all in the transport direction) as a reference, the film was stretched 3.7 times in the transport direction (dyeing step). The immersion time at this time was about 60 seconds. Then, the dyed polyvinyl alcohol film is immersed in a cross-linked bath at 40 ° C. (an aqueous solution having a boric acid concentration of 3.0% by weight and a potassium iodide concentration of 3.0% by weight) while immersing the original polyvinyl alcohol film. It was stretched up to 4.2 times in the transport direction as a reference (crosslinking step). Further, the obtained polyvinyl alcohol film is immersed in a stretching bath at 64 ° C. (an aqueous solution having a boric acid concentration of 4.0% by weight and a potassium iodide concentration of 5.0% by weight) for 50 seconds to obtain the original polyvinyl alcohol. After stretching up to 6.0 times in the transport direction with reference to the alcohol film (stretching step), it was immersed in a washing bath at 20 ° C. (an aqueous solution having a potassium iodide concentration of 3.0% by weight) for 5 seconds (washing). Process). The washed polyvinyl alcohol film was dried at 30 ° C. for 2 minutes to prepare a polarizer (thickness 23 μm).

2. Preparation of polarizing plate As an adhesive, a polyvinyl alcohol resin containing an acetoacetyl group (average degree of polymerization of 1,200, saponification degree of 98.5 mol%, acetoacetylation degree of 5 mol%) and methylol melamine are used. An aqueous solution containing a weight ratio of 3: 1 was used. Using this adhesive, a triacetyl cellulose (TAC) film with a hard coat layer having a thickness of 32 μm was applied to one surface of the above-mentioned polarizer, and a TAC film having a thickness of 20 μm was applied to the other surface of the polarizer. After laminating with a roll laminating machine, it is heated and dried in an oven (temperature is 60 ° C., time is 5 minutes) to protect layer 1 (thickness 32 μm) / adhesive layer / polarizing element / adhesive layer / protective layer 2 ( A polarizing plate having a structure having a thickness of 20 μm) was produced.

3. 3. Fabrication of circularly polarizing plate with barrier film 2. A retardation film and a barrier film were attached to the surface of the protective layer 2 of the polarizing plate obtained in the same manner as in Example 1, cut to the same size as in Example 1, and the polarizing plate / retardation layer / first. A circularly polarizing plate with a barrier film having the structure of the pressure-sensitive adhesive layer / barrier film / second pressure-sensitive adhesive layer was obtained. The obtained circularly polarizing plate with a barrier film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

The circularly polarizing plate with a barrier film of the present invention is suitably used as a circularly polarizing plate for a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

10 Polarizing plate 11 Polarizer 12 First protective layer 13 Second protective layer 20 Phase difference layer 30 First adhesive layer 40 Barrier film 41 Resin film 42 Barrier layer 50 Second adhesive layer 100 Circle with barrier film Polarizer

Claims (8)

A polarizing plate containing a polarizer, a retardation layer, a barrier film bonded to the retardation layer via a first pressure-sensitive adhesive layer, and a barrier film on the opposite side of the first pressure-sensitive adhesive layer. It has a second pressure-sensitive adhesive layer provided as an outermost layer, and has.
It can be wound in a direction orthogonal to the absorption axis direction of the polarizer.
The angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 40 ° to 50 °.
The dimensional change rate in the absorption axis direction of the polarizer after being left at 80 ° C. for 500 hours is 0.4% or less.
Circularly polarizing plate with barrier film. The barrier moisture permeability is ^{1.0 × 10 -2 g / m 2} / 24hr or less of the film, the barrier film with circular polarizer according to claim 1. The circularly polarizing plate with a barrier film according to claim 1 or 2, wherein the thickness of the barrier film is 100 μm or less. The circular polarizing plate with a barrier film according to any one of claims 1 to 3, wherein the polarizing element has a thickness of 8 μm or less. The circularly polarizing plate with a barrier film according to any one of claims 1 to 4, wherein a roll having a diameter of 20 mm to 120 mm can be formed by the winding. It has a rectangular shape having a long side extending in the absorption axis direction of the polarizer and a short side extending in a direction orthogonal to the absorption axis direction, the length of the long side is 1200 mm or more, and the length of the short side is 650 mm. The circularly polarizing plate with a barrier film according to any one of claims 1 to 5, which is as described above. A windable image display device comprising the circularly polarizing plate with a barrier film according to any one of claims 1 to 6. The rewindable image display device according to claim 7, which is an organic electroluminescence display device.

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