WO2017098970A1 - Circular polarizing plate and flexible image display device using same - Google Patents

Circular polarizing plate and flexible image display device using same Download PDF

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Publication number
WO2017098970A1
WO2017098970A1 PCT/JP2016/085470 JP2016085470W WO2017098970A1 WO 2017098970 A1 WO2017098970 A1 WO 2017098970A1 JP 2016085470 W JP2016085470 W JP 2016085470W WO 2017098970 A1 WO2017098970 A1 WO 2017098970A1
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WIPO (PCT)
Prior art keywords
polarizing plate
layer
film
retardation
circularly polarizing
Prior art date
Application number
PCT/JP2016/085470
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French (fr)
Japanese (ja)
Inventor
理 小島
清水　享
武田　健太郎
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日東電工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2016222204A external-priority patent/JP6920047B2/en
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Priority to KR1020187016410A priority Critical patent/KR102563679B1/en
Priority to SG11201804822YA priority patent/SG11201804822YA/en
Priority to CN201680071187.1A priority patent/CN108292005A/en
Publication of WO2017098970A1 publication Critical patent/WO2017098970A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/8791—Arrangements for improving contrast, e.g. preventing reflection of ambient light

Definitions

  • the present invention relates to a circularly polarizing plate and a flexible image display device using the same.
  • the organic EL display device having a flexible or bendable (foldable) structure is being put into practical use by making use of a characteristic that the liquid crystal display device does not have.
  • a conventional circularly polarizing plate is used, there is a problem that undesired bending and / or warping occurs in the organic EL display device.
  • the present invention has been made to solve the above-described conventional problems, and a main object of the present invention is to reduce the curl due to both state change and change over time, and when applied to a flexible image display device, the image display device.
  • An object of the present invention is to provide a circularly polarizing plate that can suppress undesired bending and warping.
  • the circularly polarizing plate of the present invention has a first protective layer, a polarizer, a second protective layer, and a retardation layer having an in-plane retardation Re (550) of 80 nm to 200 nm in this order.
  • the moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% is less than 160 g / m 2 / 24H.
  • This circularly polarizing plate is used for a flexible image display device.
  • the second protective layer is omitted, and the retardation layer also serves as a protective layer of the polarizer, and the moisture permeability of the retardation layer at 40 ° C. and a relative humidity of 92% is 160 g / m.
  • an angle ⁇ between the absorption axis of the polarizer and the slow axis of the retardation layer is 35 ° to 55 °.
  • the circularly polarizing plate further has a hard coat layer on the outside of the first protective layer.
  • the circularly polarizing plate further has an adhesive layer on the outermost side on the retardation layer side, and a release liner is temporarily attached to the surface of the adhesive layer.
  • the circularly polarizing plate has a surface protective film temporarily attached to the outermost part on the first protective layer side.
  • the circularly polarizing plate has a state in which the release liner and the surface protective film are temporarily attached; a state in which the release liner is peeled and removed, and a state in which the surface protective film is temporarily attached; and In each state where the release liner and the surface protective film are peeled and removed, the curl amount when placed in an environment of 25 ° C. ⁇ 5 ° C. and a relative humidity of 55% ⁇ 10% for 72 hours is within ⁇ 6 mm.
  • a flexible image display device is provided. This image display device includes the circularly polarizing plate described above.
  • the state change (typically peeling of the surface protective film and / or peeling of the release liner) is achieved by optimizing the moisture permeability of the layer adjacent to the display cell side of the polarizer in the circularly polarizing plate. ) As well as a change with time, a circularly polarizing plate having a small curl can be realized. As a result, when the circularly polarizing plate is applied to a flexible image display device, undesired bending and warping of the image display device can be satisfactorily suppressed.
  • Refractive index (nx, ny, nz) “Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
  • Refractive index (nx, ny, nz) “Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
  • In-plane retardation (Re) “Re ( ⁇ )” is an in-plane retardation measured with light having a wavelength of ⁇ nm at 23 ° C.
  • Re (550) is an in-plane retardation measured with light having a wavelength of 550 nm at 23 ° C.
  • Thickness direction retardation (Rth) is a retardation in the thickness direction measured with light having a wavelength of ⁇ nm at 23 ° C.
  • Rth (550) is a retardation in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C.
  • FIG. 1 is a schematic cross-sectional view of a circularly polarizing plate according to one embodiment of the present invention.
  • the circularly polarizing plate 100 of the present embodiment includes the first protective layer 11, the polarizer 20, the second protective layer 12, and the retardation layer 30 in this order.
  • the first protective layer 11 is on the viewing side
  • the retardation layer 30 is on the display cell side of the image display device.
  • the in-plane retardation Re (550) of the retardation layer 30 is 80 nm to 200 nm.
  • the retardation layer 30 typically functions as a so-called ⁇ / 4 plate.
  • the angle ⁇ formed by the absorption axis of the polarizer 20 and the slow axis of the retardation layer 30 is typically 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 42 ° to 48 °, more preferably about 45 °.
  • the circularly polarizing plate 100 may further include a hard coat layer 40 on the outer side of the first protective layer 11 as shown in the illustrated example.
  • the circularly polarizing plate 100 may further include another retardation layer (not shown).
  • the optical characteristics for example, in-plane retardation, thickness direction retardation, Nz coefficient, refractive index characteristic), number, combination, arrangement position, and the like of another retardation layer can be appropriately set according to the purpose.
  • the circularly polarizing plate 100 may further include a conductive layer or an isotropic substrate with a conductive layer (both not shown). In this case, the circularly polarizing plate can be applied to a so-called inner touch panel type input display device in which a touch sensor is incorporated between a display cell (for example, an organic EL cell) and a polarizing plate.
  • the circularly polarizing plate 100 may further include an adhesive layer 50 on the outermost side on the phase difference layer 30 side as shown in the example of the drawing.
  • the pressure-sensitive adhesive layer By providing the pressure-sensitive adhesive layer in advance, it can be easily bonded to another optical member (for example, a display cell of an image display device).
  • the release liner 60 is temporarily attached to the surface of the pressure-sensitive adhesive layer 50 to protect the pressure-sensitive adhesive layer 50 until the circularly polarizing plate is used.
  • the surface protective film 70 may be temporarily attached to the outermost part by the side of the 1st protective layer 11 like the example of illustration.
  • surface protective film means a film that temporarily protects the circularly polarizing plate during work, and a protective layer of a polarizer such as the first protective layer 11 and the second protective layer 12. It is different from (polarizer protective film).
  • Each layer or optical film constituting the circularly polarizing plate is laminated via any appropriate adhesive layer (adhesive layer or pressure-sensitive adhesive layer).
  • adhesive layer adhesive layer or pressure-sensitive adhesive layer.
  • a typical example of the adhesive constituting the adhesive layer is a polyvinyl alcohol-based adhesive.
  • a typical example of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.
  • the moisture permeability of the second protective layer 12 at 40 ° C. and a relative humidity of 92% is less than 160 g / m 2 / 24H.
  • the second protective layer 12 is omitted, and the retardation layer 30 can also serve as the protective layer of the polarizer 20.
  • the moisture permeability of the retardation layer 30 at 40 ° C. and a relative humidity of 92% may be less than 160 g / m 2 / 24H. That is, according to the embodiment of the present invention, by changing the moisture permeability of the layer adjacent to the display cell side of the polarizer 20, the state change (typically, the peeling of the surface protective film and / or the release liner is performed).
  • a circularly polarizing plate having a small curl can be realized by any of the above-mentioned and peeling over time.
  • the embodiment of the present invention solves the problem that has become apparent for the first time when a circularly polarizing plate is applied to a flexible (or foldable) image display device.
  • the moisture permeability of the film is affected by both the properties of the film constituent material itself and the film thickness, while maintaining the optical properties desired for the layer (film) adjacent to the display cell side of the polarizer, This is an unexpected and excellent effect obtained through repeated trial and error regarding optimization of materials and thickness.
  • the moisture permeability can be measured according to JIS Z 0208 (cup method).
  • the release liner 60 and the surface protective film 70 are temporarily attached; (ii) the release liner 60 is peeled and removed, and the surface protective film 70 is temporarily attached. And (iii) in an environment of 25 ° C. ⁇ 5 ° C. and a relative humidity of 55% ⁇ 10% in each state where the release liner 60 and the surface protection film 70 are peeled and removed (typically, a clean room environment)
  • the curl amount when placed in the lower part for 72 hours is preferably within ⁇ 6 mm, more preferably within ⁇ 5 mm, and even more preferably within ⁇ 4 mm.
  • the circularly polarizing plate according to the embodiment of the present invention is characterized in that the curl amount due to the change with time in the state (iii) is small. That is, the curl control in the states (i) and (ii) has been conventionally performed, and in the conventional rigid image display device, only the curl control in these states is sufficient. On the other hand, it has been found that by setting the curl amount due to a change with time in the state (iii) within the above range, bending and warping of the flexible (or foldable) image display device itself can be satisfactorily suppressed. By optimizing the moisture permeability of the layer adjacent to the display cell side of the polarizer as described above, it is possible to control the curl amount due to the change with time in the state (iii).
  • the first protective layer 11 is formed of any appropriate film that can be used as a protective layer for a polarizer.
  • the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials.
  • transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate.
  • thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included.
  • a glassy polymer such as a siloxane polymer is also included.
  • a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used.
  • 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 nitrile group in the side chain for example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned.
  • the polymer film can be, for example, an extruded product of the resin composition.
  • the thickness of the first protective layer any appropriate thickness can be adopted as long as the effect of the present invention is obtained.
  • the thickness of the first protective layer is, for example, 5 ⁇ m to 70 ⁇ m, preferably 15 ⁇ m to 50 ⁇ m.
  • the thickness of the first protective layer is a thickness including the thickness of the surface treatment layer.
  • the circularly polarizing plate of the present invention is typically disposed on the viewing side of the image display device, and the first protective layer 11 is typically disposed on the viewing side. Therefore, the first protective layer 11 may be subjected to any appropriate surface treatment depending on the purpose.
  • a hard coat process is performed and the hard coat layer 40 may be provided as described above.
  • the material constituting the hard coat layer include an ultraviolet curable resin mainly composed of an acrylic resin (acrylate, urethane acrylate) and an epoxy resin.
  • the hard coat layer is formed by coating and drying a solution containing such a monomer or oligomer of an ultraviolet curable resin and, if necessary, a photopolymerization initiator and a leveling agent on the first protective layer.
  • the first protective layer 11 is provided with a treatment for improving visibility when viewed through polarized sunglasses (typically, imparting an (elliptical) circular polarization function, (Giving an ultrahigh phase difference) may be applied.
  • polarized sunglasses typically, imparting an (elliptical) circular polarization function, (Giving an ultrahigh phase difference) may be applied.
  • Polarizer 20 Any appropriate polarizer may be adopted as the polarizer 20.
  • the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.
  • polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films.
  • PVA polyvinyl alcohol
  • polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products.
  • a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.
  • the dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution.
  • the stretching 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. Moreover, you may dye
  • the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.
  • a polarizer obtained by using a laminate a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin
  • a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate.
  • a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it.
  • a PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain.
  • stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching.
  • the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid 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 layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate.
  • Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.
  • the thickness of the polarizer is preferably 25 ⁇ m or less, more preferably 1 ⁇ m to 22 ⁇ m, still more preferably 1 ⁇ m to 12 ⁇ m, and particularly preferably 3 ⁇ m to 12 ⁇ m.
  • the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.
  • the polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm.
  • the single transmittance of the polarizer is 43.0% to 46.0%, preferably 44.5% to 46.0%.
  • the polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.
  • the second protective layer 12 has a moisture permeability of less than 160 g / m 2 / 24H, preferably 155 g / m 2 / 24H or less, as described above, at 40 ° C. and a relative humidity of 92%. Preferably it is 150 g / m ⁇ 2 > / 24H or less.
  • the circularly polarizing plate has a small curl due to any of the state change (typically peeling of the surface protective film and / or release liner) and change with time. Can be realized.
  • the minimum of the water vapor transmission rate of a 2nd protective layer is 10 g / m ⁇ 2 > / 24H, for example.
  • the second protective layer is formed of any appropriate film that can be used as a protective layer for the polarizer as long as it can have the above moisture permeability.
  • a typical example of a material for forming the second protective layer is an acrylic resin.
  • a (meth) acrylic resin having a glutarimide structure is used as the acrylic resin.
  • Examples of the (meth) acrylic resin having a glutarimide structure include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, and JP-A-2006.
  • a (meth) acrylic resin having a lactone ring structure is used as the acrylic resin.
  • (meth) acrylic resins having a lactone ring structure include, for example, JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. -146084. These descriptions are incorporated herein by reference.
  • the (meth) acrylic resin has a Tg (glass transition temperature) of preferably 115 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 125 ° C. or higher, and particularly preferably 130 ° C. or higher. It is because it can be excellent in durability.
  • Tg glass transition temperature
  • the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From viewpoints of a moldability etc., Preferably it is 170 degrees C or less.
  • the (meth) acrylic resin has a mass average molecular weight (sometimes referred to as a weight average molecular weight) of preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, and particularly preferably 50,000 to 500,000. It is.
  • the second protective layer 12 is preferably optically isotropic.
  • “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.
  • the thickness of the second protective layer is, for example, 15 ⁇ m to 35 ⁇ m, preferably 15 ⁇ m to 25 ⁇ m. With such a thickness, the above moisture permeability can be realized while maintaining desired optical characteristics as a protective layer on the inner side (display cell side) of the polarizer.
  • the retardation layer 30 may have any suitable optical and / or mechanical properties depending on the purpose.
  • the retardation layer 30 typically has a slow axis.
  • the angle ⁇ formed by the slow axis of the retardation layer 30 and the absorption axis of the polarizer 11 is typically 35 ° to 55 °, preferably 38 ° to 52 °, and more preferably. Is between 42 ° and 48 °, more preferably about 45 °. If the angle ⁇ is in such a range, the retardation layer 30 is a ⁇ / 4 plate as will be described later, thereby having very excellent circular polarization characteristics (as a result, very excellent antireflection characteristics). A circularly polarizing plate can be obtained.
  • the retardation layer 30 preferably has a relationship in refractive index characteristics of nx> ny ⁇ nz.
  • the retardation layer is typically provided for imparting antireflection properties to the polarizing plate and can function as a ⁇ / 4 plate.
  • the in-plane retardation Re (550) of the retardation layer is from 80 nm to 200 nm, preferably from 100 nm to 180 nm, and more preferably from 110 nm to 170 nm.
  • the Nz coefficient of the 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 1.3. .
  • the retardation layer may exhibit reverse dispersion wavelength characteristics in which the retardation value increases with the wavelength of the measurement light, or may exhibit positive wavelength dispersion characteristics in which the retardation value decreases with the wavelength of the measurement light.
  • the phase difference value may exhibit a flat chromatic dispersion characteristic that hardly changes depending on the wavelength of the measurement light.
  • the retardation layer exhibits reverse dispersion wavelength characteristics.
  • 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 retardation layer exhibits flat chromatic dispersion characteristics.
  • Re (450) / Re (550) of the retardation layer is preferably from 0.99 to 1.03, and Re (650) / Re (550) is preferably from 0.98 to 1.02. is there.
  • the absolute value of photoelastic coefficient of preferably 2 ⁇ 10 -11 m 2 / N or less, more preferably 2.0 ⁇ 10 -13 m 2 /N ⁇ 1.5 ⁇ 10 -11 m 2 / N, more preferably includes a resin of 1.0 ⁇ 10 -12 m 2 /N ⁇ 1.2 ⁇ 10 -11 m 2 / N.
  • the retardation layer has a moisture permeability of 160 g / m at 40 ° C. and a relative humidity of 92% as described above. It is less than 2 / 24H, preferably 120 g / m 2 / 24H or less, more preferably 100 g / m 2 / 24H or less.
  • the moisture permeability is less than 2 / 24H, preferably 120 g / m 2 / 24H or less, more preferably 100 g / m 2 / 24H or less.
  • the circularly polarizing plate has a small curl due to any of the state change (typically peeling of the surface protective film and / or release liner) and change with time. Can be realized.
  • the minimum of the water vapor transmission rate of a phase difference layer is 10 g / m ⁇ 2 > / 24H, for example.
  • the thickness of the retardation layer is preferably 60 ⁇ m or less, and preferably 30 ⁇ m to 58 ⁇ m. With such a thickness, the above moisture permeability can be realized while maintaining desired optical characteristics as a ⁇ / 4 plate imparting a circularly polarizing function.
  • the retardation layer 30 can be composed of any appropriate resin film that can satisfy the above-described characteristics.
  • Typical examples of such resins include cyclic olefin resins, polycarbonate resins, cellulose resins, polyester resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, acrylic resins. Based resins.
  • a polycarbonate-based resin can be suitably used, and when it is composed of a resin film exhibiting flat wavelength dispersion characteristics, a cyclic olefin-based resin is suitable. Can be used.
  • the polycarbonate resin any appropriate polycarbonate resin can be used as long as the effects of the present invention can be obtained.
  • the polycarbonate resin includes 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.
  • the polycarbonate resin is derived from 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 a di-, tri- or polyethylene glycol. More preferably, a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol.
  • the polycarbonate resin may contain structural units derived from other dihydroxy compounds as necessary. Details of the polycarbonate resin that can be suitably used in the present invention are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-10291 and 2014-26266, and the description is incorporated herein by reference. The
  • a polycarbonate-based resin containing an oligofluorene structural unit can be used.
  • the polycarbonate-based resin containing an oligofluorene structural unit include a resin containing a structural unit represented by the following general formula (1) and / or a structural unit represented by the following general formula (2).
  • R 5 and R 6 are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms (preferably on the main chain).
  • R 7 is a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms (preferably having 1 to 2 carbon atoms on the main chain).
  • R 8 to R 13 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted A substituted aryl group having 4 to 10 carbon atoms (preferably 4 to 8, more preferably 4 to 7), a substituted or unsubstituted carbon group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2) Acyl group, substituted or unsubstituted, 1 to 0 (preferably 1 to 4, more preferably 1 to 2) alkoxy group, substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted An unsubstituted acyloxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), a substituted or unsubstituted amino group, and a substituted or unsubstituted carbon
  • the fluorene ring contained in the oligofluorene structural unit has a configuration in which all of R 8 to R 13 are hydrogen atoms, or R 8 and / or R 13 is a halogen atom or an acyl group. , A nitro group, a cyano group, and a sulfo group, and R 9 to R 12 are hydrogen atoms.
  • the glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 150 ° C. or lower, more preferably 120 ° C. or higher and 140 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, there is a possibility of causing a dimensional change after film formation, and the image quality of the resulting organic EL panel may be lowered. If the glass transition temperature is excessively high, the molding stability at the time of film molding may deteriorate, 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 represented by a reduced viscosity.
  • the reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ⁇ 0.1 ° C., using methylene chloride as a solvent, precisely adjusting the polycarbonate concentration to 0.6 g / dL.
  • the lower limit of the reduced viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or more.
  • the upper limit of the reduced viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, still more preferably 0.80 dL / g.
  • the reduced viscosity is less than the lower limit, there may be a problem that the mechanical strength of the molded product is reduced.
  • the reduced viscosity is larger than the upper limit, the fluidity at the time of molding is lowered, and there may be a problem that productivity and moldability are lowered.
  • a commercially available film may be used as the polycarbonate resin film.
  • Specific examples of commercially available products include “Pure Ace WR-S”, “Pure Ace WR-W”, “Pure Ace WR-M” manufactured by Teijin Limited, and “NRF” manufactured by Nitto Denko Corporation. It is done.
  • the cyclic olefin-based resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and ⁇ -olefins such as ethylene and propylene (typically random copolymers).
  • graft modified products in which these are modified with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof.
  • the cyclic olefin include norbornene monomers.
  • the norbornene-based monomer include norbornene and alkyl and / or alkylidene substituted products thereof such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl- 2-Norbornene, 5-ethylidene-2-norbornene, etc.
  • Polar group substitution products such as halogens; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, alkyl and / or alkylidene substitution thereof
  • polar group substituents such as halogen, for example, 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl -1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahi Lonaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano
  • cycloolefins capable of ring-opening polymerization can be used in combination as long as the object of the present invention is not impaired.
  • cycloolefins include compounds having one reactive double bond such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.
  • the cyclic olefin resin preferably has a number average molecular weight (Mn) measured by a gel permeation chromatograph (GPC) method using a toluene solvent, preferably 25,000 to 200,000, more preferably 30,000 to 100,000. 000, most preferably 40,000 to 80,000.
  • Mn number average molecular weight measured by a gel permeation chromatograph (GPC) method using a toluene solvent, preferably 25,000 to 200,000, more preferably 30,000 to 100,000. 000, most preferably 40,000 to 80,000.
  • a commercially available film may be used as the cyclic olefin resin film.
  • Specific examples include trade names “ZEONEX” and “ZEONOR” manufactured by ZEON CORPORATION, “Arton” manufactured by JSR, “TOPAS” trade name manufactured by TICONA, and trade names manufactured by Mitsui Chemicals, Inc. “APEL” may be mentioned.
  • the retardation layer 30 is obtained, for example, by stretching a film formed from the resin.
  • Any appropriate forming method can be adopted as a method of forming a film from a resin. Specific examples include compression molding methods, transfer molding methods, injection molding methods, extrusion molding methods, blow molding methods, powder molding methods, FRP molding methods, cast coating methods (for example, casting methods), calendar molding methods, and hot presses. Law. Extrusion molding or cast coating is preferred. This is because the smoothness of the resulting 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 properties desired for the retardation layer, and the like. In addition, as above-mentioned, since many film products are marketed for polycarbonate-type resin or cyclic olefin-type resin, you may use the said commercial film as it is for a extending
  • the thickness of the resin film can be set to any appropriate value depending on the desired thickness of the retardation layer, the desired optical properties, the stretching conditions described below, and the like.
  • the thickness is preferably 50 ⁇ m to 300 ⁇ m.
  • Any appropriate stretching method and stretching conditions may be employed for the stretching.
  • various stretching methods such as free end stretching, fixed end stretching, free end contraction, and fixed end contraction can be used singly or simultaneously or sequentially.
  • the stretching direction can also be performed in various directions and dimensions such as a length direction, a width direction, a thickness direction, and an oblique direction.
  • the retardation film is produced by uniaxially stretching a resin film or uniaxially stretching a fixed end.
  • the fixed end uniaxial stretching there is a method of stretching in the width direction (lateral direction) while running the resin film in the longitudinal direction.
  • the draw ratio is preferably 1.1 to 3.5 times.
  • the retardation film can be produced by continuously stretching a long resin film obliquely in the direction of the angle ⁇ described above with respect to the longitudinal direction.
  • a long stretched film having an orientation angle of ⁇ with respect to the longitudinal direction of the film (slow axis in the direction of angle ⁇ ) can be obtained.
  • the angle ⁇ may be an angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer in the circularly polarizing plate.
  • the angle ⁇ is typically 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 42 ° to 48 °, and further preferably about 45 °.
  • Examples of the stretching machine used for the oblique stretching include a tenter type stretching machine capable of adding feed forces, pulling forces, or pulling forces at different speeds in the lateral and / or longitudinal 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 a long resin film can be continuously stretched obliquely.
  • the retardation layer having the desired in-plane retardation and having the slow axis in the desired direction (substantially long) Shaped retardation film) can be obtained.
  • the stretching temperature of the film can vary 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 + 60 ° C, more preferably Tg-15 ° C to Tg + 55 ° C, and most preferably Tg-10 ° C to Tg + 50 ° C. By extending
  • a retardation film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained by appropriately selecting the stretching method and stretching conditions.
  • Conductive layer or isotropic substrate with conductive layer The conductive layer can be formed by any suitable film formation method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.).
  • a metal oxide film can be formed thereon.
  • the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.
  • the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less.
  • the lower limit of the thickness of the conductive layer is preferably 10 nm.
  • the conductive layer may be transferred from the base material to the retardation layer, and the conductive layer alone may be a constituent layer of a circularly polarizing plate, and is laminated on the retardation layer as a laminate (base material with a conductive layer) with the base material. May be.
  • the base material is optically isotropic, and therefore the conductive layer can be used for a circularly polarizing plate as an isotropic base material with a conductive layer.
  • any appropriate isotropic substrate can be adopted.
  • a material constituting the isotropic substrate for example, a material having a main skeleton such as a norbornene resin or an olefin resin as a main skeleton, or a cyclic structure such as a lactone ring or a glutarimide ring is used for an acrylic resin. Examples thereof include materials possessed in the main chain. When such a material is used, when an isotropic substrate is formed, it is possible to suppress the expression of the phase difference accompanying the orientation of the molecular chain.
  • the thickness of the isotropic substrate is preferably 50 ⁇ m or less, more preferably 35 ⁇ m or less.
  • the lower limit of the thickness of the isotropic substrate is, for example, 20 ⁇ m.
  • the conductive layer and / or the conductive layer of the isotropic base material with the conductive layer may be patterned as necessary. By conducting the patterning, a conductive portion and an insulating portion can be formed. As a result, an electrode can be formed.
  • the electrode can function as a touch sensor electrode that senses contact with the touch panel. Any appropriate method can be adopted as the patterning method. Specific examples of the patterning method include a wet etching method and a screen printing method.
  • the circularly polarizing plate described in the items A to F can be applied to a flexible image display device. Therefore, the present invention includes a flexible image display device using such a circularly polarizing plate.
  • a typical example of a flexible image display device is an organic EL display device.
  • the flexible image display apparatus by embodiment of this invention is equipped with the circularly-polarizing plate as described in said A term to F term in the visual recognition side.
  • the circularly polarizing plate is laminated so that the retardation layer is on the display cell (for example, organic EL cell) side (so that the polarizer is on the viewing side).
  • a flexible organic EL display device can be realized, for example, by configuring a substrate of an organic EL cell with a flexible or foldable material.
  • a material typically, thin glass provided with flexibility, a thermoplastic resin or a thermosetting resin film, an alloy, and a metal can be given.
  • the thermoplastic resin or thermosetting resin include polyester resins, polyimide resins, epoxy resins, polyurethane resins, polystyrene resins, polyolefin resins, polyamide resins, polycarbonate resins, silicone resins, fluorine And acrylonitrile-butadiene-styrene copolymer resin.
  • the alloy include stainless steel, 36 alloy, and 42 alloy.
  • the metal include copper, nickel, iron, aluminum, and titanium.
  • the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.
  • the measuring method of each characteristic is as follows.
  • Thickness The thickness was measured using a digital micrometer (KC-351C manufactured by Anritsu).
  • Retardation value of retardation layer Refractive index nx, ny and nz of the retardation layer used in the examples and comparative examples were determined using an automatic birefringence measuring device (manufactured by Oji Scientific Instruments, automatic birefringence meter KOBRA- WPR).
  • the measurement wavelength of the in-plane retardation Re was 450 nm and 550 nm
  • the measurement wavelength of the thickness direction retardation Rth was 550 nm
  • the measurement temperature was 23 ° C.
  • Moisture permeability The film constituting the second protective layer or retardation layer was measured according to JIS Z 0208 (cup method).
  • the weight ratio of iodine and potassium iodide is 1: 7, the iodine concentration of which is adjusted so that the single transmittance of the obtained polarizer is 45.0%.
  • the film was stretched 1.4 times.
  • the crosslinking treatment employed a two-stage crosslinking treatment, and the first-stage crosslinking treatment was stretched 1.2 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 40 ° C.
  • the boric acid content of the aqueous solution of the first-stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight.
  • the cross-linking treatment at the second stage was stretched 1.6 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C.
  • the boric acid content of the aqueous solution of the second crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight.
  • the cleaning treatment was performed with an aqueous potassium iodide solution at 20 ° C.
  • the potassium iodide content of the aqueous solution for the washing treatment was 2.6% by weight.
  • the drying process was performed at 70 ° C. for 5 minutes to obtain a polarizer 1.
  • a methacrylic resin film having a glutarimide ring structure (thickness: 20 ⁇ m, corresponding to the second protective layer) and a TAC film are hard coated on both sides of the obtained polarizer 1 via a polyvinyl alcohol adhesive.
  • HC-TAC films (thickness: 47 ⁇ m, corresponding to the first protective layer) each having a hard coat (HC) layer formed by the treatment were bonded together, and the first protective layer / polarizer 1 / second
  • the polarizing plate 1 which has the structure of a protective layer was obtained.
  • the methacrylic resin film which has a glutarimide ring structure was produced as follows.
  • the methacrylic resin pellets having a glutarimide ring structure were dried at 100.5 kPa and 100 ° C. for 12 hours, and extruded from a T-die at a die temperature of 270 ° C. with a single screw extruder to form a film.
  • the obtained film is stretched in the transport direction (MD) in an atmosphere 10 ° C. higher than the glass transition temperature Tg of the resin, and then the glass transition of the resin in the direction (TD) orthogonal to the transport direction.
  • the film was stretched in an atmosphere 7 ° C. higher than the temperature Tg.
  • the resulting film was substantially optically isotropic.
  • HC-PC film (thickness: 25 ⁇ m, having a hard coat (HC) layer formed on one side of the polycarbonate resin film on one side of the obtained polarizer 2 via a polyvinyl alcohol adhesive by a hard coat treatment.
  • the polarizing plate 2 having the configuration of the first protective layer / polarizer 2 was obtained.
  • the pressure in the reaction vessel was changed from normal pressure to 13.3 kPa, and the generated phenol was extracted out of the reaction vessel while the temperature of the heat medium in the reaction vessel was increased to 190 ° C. over 1 hour.
  • the pressure in the reaction vessel is set to 6.67 kPa, and the heat medium temperature of the reaction vessel is increased to 230 ° C. in 15 minutes.
  • the generated phenol was extracted out of the reaction vessel. Since the stirring torque of the stirrer increased, the temperature was raised to 250 ° C. in 8 minutes, and the pressure in the reaction vessel was reduced to 0.200 kPa or less in order to remove the generated phenol.
  • the obtained polycarbonate resin had a glass transition temperature of 136.6 ° C. and a reduced viscosity of 0.395 dL / g.
  • the obtained polycarbonate resin was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (made by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 200 mm, set temperature: 220). ° C.), a chill roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winder, a 120 ⁇ m thick polycarbonate resin film was produced.
  • Retardation Film Using a tenter stretching machine, the obtained polycarbonate resin film was horizontally stretched to obtain a retardation film having a thickness of 50 ⁇ m. At that time, the draw ratio was 250%, and the draw temperature was 137 to 139 ° C. Re (550) of the obtained retardation film is 137 to 147 nm, Re (450) / Re (550) is 0.89, Nz coefficient is 1.21, orientation angle (slow axis) Direction) was 90 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 1.
  • Re (550) of the obtained retardation film is 147 nm
  • Re (450) / Re (550) is 0.89
  • Nz coefficient is 1.21
  • orientation angle (direction of slow axis) was 90 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 2.
  • Re (550) of the obtained retardation film is 141 nm, Re (450) / Re (550) is 0.83, Nz coefficient is 1.1, and photoelastic coefficient is 16 ⁇ 10 ⁇ 12.
  • the orientation angle (the direction of the slow axis) was 45 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 3.
  • Example 1 The second protective layer surface of the polarizing plate 1 and the retardation layer 1 are bonded via an acrylic pressure-sensitive adhesive so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °.
  • a circularly polarizing plate 1 was obtained.
  • An acrylic pressure-sensitive adhesive layer (thickness 15 ⁇ m) was provided on the phase difference layer surface of the obtained circularly polarizing plate 1, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer.
  • a surface protective film was temporarily attached to the first protective layer surface.
  • the protective film used was a 38 ⁇ m thick PET film coated with a 10 ⁇ m thick adhesive.
  • the moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% was 150 g / m 2 / 24H.
  • the obtained circularly polarizing plate 1 was subjected to the curl amount evaluation described in (4) above. The results are shown in Table 1. Furthermore, the organic EL cell was taken out from a flexible organic EL display device (product name “Galaxy S6 Edge” manufactured by Samsung). On the other hand, the release liner was peeled from the circularly polarizing plate 1, and the circularly polarizing plate 1 was bonded to the organic EL cell via an adhesive layer. Furthermore, the surface protective film was peeled from the circularly polarizing plate bonded to the organic EL cell. The organic EL cell on which the circularly polarizing plate 1 was bonded was allowed to stand for 72 hours at 23 ° C. and 55% RH, and then visually observed for warpage. As a result, neither warping nor bending was observed.
  • Example 2 The polarizer surface of the polarizing plate 2 and the retardation layer 2 are bonded through a PVA adhesive so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °.
  • a circularly polarizing plate 2 was obtained.
  • An acrylic pressure-sensitive adhesive layer (thickness 15 ⁇ m) was provided on the phase difference layer surface of the obtained circularly polarizing plate 2, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface.
  • the water permeability of the retardation layer at 40 ° C. and a relative humidity of 92% was 70 g / m 2 / 24H.
  • the obtained circularly polarizing plate 2 was subjected to the curl amount evaluation of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 2 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, neither warping nor bending was observed.
  • Example 3 The polarizer surface of the polarizing plate 5 and the retardation layer 3 are bonded together via a PVA adhesive so that the angle between the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °.
  • a circularly polarizing plate 5 was obtained.
  • An acrylic pressure-sensitive adhesive layer (thickness 20 ⁇ m) was provided on the phase difference layer surface of the obtained circularly polarizing plate 5, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface.
  • the water vapor permeability of the retardation layer at 40 ° C. and a relative humidity of 92% was 80 g / m 2 / 24H.
  • the obtained circularly polarizing plate 5 was subjected to the evaluation of the curl amount of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 5 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, neither warping nor bending was observed.
  • the obtained circularly polarizing plate 3 was subjected to the curl amount evaluation of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 3 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, warpage was recognized.
  • the obtained circularly polarizing plate 4 was subjected to the evaluation of the curl amount of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 4 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, warpage was recognized.
  • the circularly polarizing plate of the present invention is suitably used for a flexible image display device (for example, an organic EL display device).

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  • General Physics & Mathematics (AREA)
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Abstract

Provided is a circular polarizing plate which has a low susceptibility to curling caused by changes in state or changes over time, and which, when employed in a flexible image display device, can suppress curvature and warpage undesirable in the image display device. The circular polarizing plate of the present invention has, in the following order, a first protective layer, a polarizer, a second protective layer, and a retardation layer having an in-plane retardation Re (550) of 80-200 nm. The moisture permeability of the second protective layer at 40°C and 92% relative humidity is below 160 g/m2/24H. This circular polarizing plate can be used in a flexible image display device.

Description

円偏光板およびそれを用いたフレキシブルな画像表示装置Circularly polarizing plate and flexible image display device using the same
　本発明は、円偏光板およびそれを用いたフレキシブルな画像表示装置に関する。 The present invention relates to a circularly polarizing plate and a flexible image display device using the same.
　近年、スマートフォンに代表されるスマートデバイス、またデジタルサイネージやウィンドウディスプレイなどの表示装置が強い外光の下使用される機会が増加している。それに伴い、表示装置自体または表示装置に用いられるタッチパネル部やガラス基板、金属配線等の反射体による外光反射や背景の映り込み等の問題が生じている。特に、近年実用化されてきている有機エレクトロルミネッセンス（ＥＬ）表示装置は、反射性の高い金属層を有するため、外光反射や背景の映り込み等の問題を生じやすい。そこで、位相差フィルム（代表的にはλ／４板）を有する円偏光板を視認側に反射防止フィルムとして設けることにより、これらの問題を防ぐことが知られている。 In recent years, smart devices typified by smartphones and display devices such as digital signage and window displays have been increasingly used under strong external light. Along with this, problems such as reflection of external light and reflection of the background due to the display device itself or a reflector such as a touch panel unit, a glass substrate, and metal wiring used in the display device have arisen. In particular, since organic electroluminescence (EL) display devices that have been put into practical use in recent years have a highly reflective metal layer, problems such as external light reflection and background reflection tend to occur. Therefore, it is known to prevent these problems by providing a circularly polarizing plate having a retardation film (typically a λ / 4 plate) on the viewing side as an antireflection film.
　ところで、有機ＥＬ表示装置については、液晶表示装置にはない特徴を生かし、フレキシブルまたは屈曲可能（フォルダブル）な構成を有する有機ＥＬ表示装置の実用化が進められている。しかし、従来の円偏光板を用いると、有機ＥＬ表示装置に所望でない屈曲および／または反りが生じるという問題がある。 By the way, with respect to the organic EL display device, the organic EL display device having a flexible or bendable (foldable) structure is being put into practical use by making use of a characteristic that the liquid crystal display device does not have. However, when a conventional circularly polarizing plate is used, there is a problem that undesired bending and / or warping occurs in the organic EL display device.
特開２０１０－１３９５４８号公報JP 2010-139548 A 特開２００３－２０７６４０号公報JP 2003-207640 A 特開２００４－２２６８４２号公報JP 2004-226842 A 特許第３８１５７９０号Japanese Patent No. 3815790 特開２０１４－１７０２２１号公報JP 2014-170221 A
　本発明は上記従来の課題を解決するためになされたものであり、その主たる目的は、状態変化および経時変化のいずれによってもカールが小さく、フレキシブルな画像表示装置に適用した場合に当該画像表示装置の所望でない屈曲および反りを抑制し得る円偏光板を提供することにある。 The present invention has been made to solve the above-described conventional problems, and a main object of the present invention is to reduce the curl due to both state change and change over time, and when applied to a flexible image display device, the image display device. An object of the present invention is to provide a circularly polarizing plate that can suppress undesired bending and warping.
　本発明の円偏光板は、第１の保護層と、偏光子と、第２の保護層と、面内位相差Ｒｅ（５５０）が８０ｎｍ～２００ｎｍである位相差層と、をこの順に有し、該第２の保護層の４０℃、相対湿度９２％における透湿度が１６０ｇ／ｍ２／２４Ｈ未満である。この円偏光板は、フレキシブルな画像表示装置に用いられる。
　１つの実施形態においては、上記第２の保護層が省略されて上記位相差層が上記偏光子の保護層を兼ね、該位相差層の４０℃、相対湿度９２％における透湿度が１６０ｇ／ｍ２／２４Ｈ未満である。
　１つの実施形態においては、上記偏光子の吸収軸と上記位相差層の遅相軸とのなす角度θは３５°～５５°である。
　１つの実施形態においては、上記円偏光板は、上記第１の保護層の外側にハードコート層をさらに有する。
　１つの実施形態においては、上記円偏光板は、上記位相差層側の最外部に粘着剤層をさらに有し、該粘着剤層表面にリリースライナーが仮着されている。
　１つの実施形態においては、上記円偏光板は、上記第１の保護層側の最外部に表面保護フィルムが仮着されている。
　１つの実施形態においては、上記円偏光板は、上記リリースライナーおよび上記表面保護フィルムが仮着された状態；該リリースライナーが剥離除去され、該表面保護フィルムが仮着された状態；ならびに、該リリースライナーおよび該表面保護フィルムが剥離除去された状態のそれぞれの状態において、２５℃±５℃、相対湿度５５％±１０％の環境下に７２時間置いた場合のカール量が±６ｍｍ以内である。
　本発明の別の局面によれば、フレキシブルな画像表示装置が提供される。この画像表示装置は、上記の円偏光板を備える。 The circularly polarizing plate of the present invention has a first protective layer, a polarizer, a second protective layer, and a retardation layer having an in-plane retardation Re (550) of 80 nm to 200 nm in this order. The moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% is less than 160 g / m 2 / 24H. This circularly polarizing plate is used for a flexible image display device.
In one embodiment, the second protective layer is omitted, and the retardation layer also serves as a protective layer of the polarizer, and the moisture permeability of the retardation layer at 40 ° C. and a relative humidity of 92% is 160 g / m. It is less than 2 / 24H.
In one embodiment, an angle θ between the absorption axis of the polarizer and the slow axis of the retardation layer is 35 ° to 55 °.
In one embodiment, the circularly polarizing plate further has a hard coat layer on the outside of the first protective layer.
In one embodiment, the circularly polarizing plate further has an adhesive layer on the outermost side on the retardation layer side, and a release liner is temporarily attached to the surface of the adhesive layer.
In one embodiment, the circularly polarizing plate has a surface protective film temporarily attached to the outermost part on the first protective layer side.
In one embodiment, the circularly polarizing plate has a state in which the release liner and the surface protective film are temporarily attached; a state in which the release liner is peeled and removed, and a state in which the surface protective film is temporarily attached; and In each state where the release liner and the surface protective film are peeled and removed, the curl amount when placed in an environment of 25 ° C. ± 5 ° C. and a relative humidity of 55% ± 10% for 72 hours is within ± 6 mm. .
According to another aspect of the present invention, a flexible image display device is provided. This image display device includes the circularly polarizing plate described above.
　本発明によれば、円偏光板において偏光子の表示セル側に隣接する層の透湿度を最適化することにより、状態変化（代表的には、表面保護フィルムの剥離および／またはリリースライナーの剥離）ならびに経時変化のいずれによってもカールが小さい円偏光板を実現することができる。その結果、円偏光板をフレキシブルな画像表示装置に適用した場合に、当該画像表示装置の所望でない屈曲および反りを良好に抑制することができる。 According to the present invention, the state change (typically peeling of the surface protective film and / or peeling of the release liner) is achieved by optimizing the moisture permeability of the layer adjacent to the display cell side of the polarizer in the circularly polarizing plate. ) As well as a change with time, a circularly polarizing plate having a small curl can be realized. As a result, when the circularly polarizing plate is applied to a flexible image display device, undesired bending and warping of the image display device can be satisfactorily suppressed.
本発明の１つの実施形態による円偏光板の概略断面図である。It is a schematic sectional drawing of the circularly-polarizing plate by one Embodiment of this invention.
　以下、本発明の実施形態について説明するが、本発明はこれらの実施形態には限定されない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.
（用語および記号の定義）
　本明細書における用語および記号の定義は下記の通りである。
（１）屈折率（ｎｘ、ｎｙ、ｎｚ）
　「ｎｘ」は面内の屈折率が最大になる方向（すなわち、遅相軸方向）の屈折率であり、「ｎｙ」は面内で遅相軸と直交する方向（すなわち、進相軸方向）の屈折率であり、「ｎｚ」は厚み方向の屈折率である。
（２）面内位相差（Ｒｅ）
　「Ｒｅ（λ）」は、２３℃における波長λｎｍの光で測定した面内位相差である。例えば、「Ｒｅ（５５０）」は、２３℃における波長５５０ｎｍの光で測定した面内位相差である。Ｒｅ（λ）は、層（フィルム）の厚みをｄ（ｎｍ）としたとき、式：Ｒｅ（λ）＝（ｎｘ－ｎｙ）×ｄによって求められる。
（３）厚み方向の位相差（Ｒｔｈ）
　「Ｒｔｈ（λ）」は、２３℃における波長λｎｍの光で測定した厚み方向の位相差である。例えば、「Ｒｔｈ（５５０）」は、２３℃における波長５５０ｎｍの光で測定した厚み方向の位相差である。Ｒｔｈ（λ）は、層（フィルム）の厚みをｄ（ｎｍ）としたとき、式：Ｒｔｈ（λ）＝（ｎｘ－ｎｚ）×ｄによって求められる。
（４）Ｎｚ係数
　Ｎｚ係数は、Ｎｚ＝Ｒｔｈ／Ｒｅによって求められる。 (Definition of terms and symbols)
The definitions of terms and symbols in this specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction). “Nz” is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
“Re (λ)” is an in-plane retardation measured with light having a wavelength of λ nm at 23 ° C. For example, “Re (550)” is an in-plane retardation measured with light having a wavelength of 550 nm at 23 ° C. Re (λ) is determined by the formula: Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the layer (film).
(3) Thickness direction retardation (Rth)
“Rth (λ)” is a retardation in the thickness direction measured with light having a wavelength of λ nm at 23 ° C. For example, “Rth (550)” is a retardation in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. Rth (λ) is determined 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.
Ａ．円偏光板の全体構成
　本発明の実施形態による円偏光板は、代表的には、フレキシブルな画像表示装置（代表的には、有機ＥＬ表示装置）に用いられ得る。図１は、本発明の１つの実施形態による円偏光板の概略断面図である。本実施形態の円偏光板１００は、第１の保護層１１と、偏光子２０と、第２の保護層１２と、位相差層３０と、をこの順に有する。円偏光板１００においては、代表的には、第１の保護層１１が視認側となり、位相差層３０が画像表示装置の表示セル側となる。位相差層３０の面内位相差Ｒｅ（５５０）は、８０ｎｍ～２００ｎｍである。位相差層３０は、代表的には、いわゆるλ／４板として機能する。偏光子２０の吸収軸と位相差層３０の遅相軸とのなす角度θは、代表的には３５°～５５°であり、好ましくは３８°～５２°であり、より好ましくは４２°～４８°であり、さらに好ましくは約４５°である。 A. Overall Configuration of Circular Polarizing Plate The circularly polarizing plate according to the embodiment of the present invention can be typically used for a flexible image display device (typically, an organic EL display device). FIG. 1 is a schematic cross-sectional view of a circularly polarizing plate according to one embodiment of the present invention. The circularly polarizing plate 100 of the present embodiment includes the first protective layer 11, the polarizer 20, the second protective layer 12, and the retardation layer 30 in this order. In the circularly polarizing plate 100, typically, the first protective layer 11 is on the viewing side, and the retardation layer 30 is on the display cell side of the image display device. The in-plane retardation Re (550) of the retardation layer 30 is 80 nm to 200 nm. The retardation layer 30 typically functions as a so-called λ / 4 plate. The angle θ formed by the absorption axis of the polarizer 20 and the slow axis of the retardation layer 30 is typically 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 42 ° to 48 °, more preferably about 45 °.
　１つの実施形態においては、円偏光板１００は、図示例のように第１の保護層１１の外側にハードコート層４０をさらに有していてもよい。１つの実施形態においては、円偏光板１００は、別の位相差層（図示せず）をさらに有していてもよい。別の位相差層の光学特性（例えば、面内位相差、厚み方向位相差、Ｎｚ係数、屈折率特性）、数、組み合わせ、配置位置等は目的に応じて適切に設定され得る。１つの実施形態においては、円偏光板１００は、導電層または導電層付等方性基材（いずれも図示せず）をさらに有していてもよい。この場合、円偏光板は、表示セル（例えば、有機ＥＬセル）と偏光板との間にタッチセンサが組み込まれた、いわゆるインナータッチパネル型入力表示装置に適用され得る。 In one embodiment, the circularly polarizing plate 100 may further include a hard coat layer 40 on the outer side of the first protective layer 11 as shown in the illustrated example. In one embodiment, the circularly polarizing plate 100 may further include another retardation layer (not shown). The optical characteristics (for example, in-plane retardation, thickness direction retardation, Nz coefficient, refractive index characteristic), number, combination, arrangement position, and the like of another retardation layer can be appropriately set according to the purpose. In one embodiment, the circularly polarizing plate 100 may further include a conductive layer or an isotropic substrate with a conductive layer (both not shown). In this case, the circularly polarizing plate can be applied to a so-called inner touch panel type input display device in which a touch sensor is incorporated between a display cell (for example, an organic EL cell) and a polarizing plate.
　実用的には、円偏光板１００は、図示例のように位相差層３０側の最外部に粘着剤層５０をさらに有していてもよい。粘着剤層が予め設けられていることにより、他の光学部材（例えば、画像表示装置の表示セル）へ容易に貼り合わせることができる。この場合、円偏光板が使用に供されるまで、粘着剤層５０表面にはリリースライナー６０が仮着され、粘着剤層５０を保護することが好ましい。さらに、実用的には、円偏光板１００は、図示例のように第１の保護層１１側の最外部に表面保護フィルム７０が仮着されていてもよい。なお、本明細書で表面保護フィルムというときは、作業時に円偏光板を一時的に保護するフィルムを意味し、第１の保護層１１、第２の保護層１２のような偏光子の保護層（偏光子保護フィルム）とは異なるものである。 Practically, the circularly polarizing plate 100 may further include an adhesive layer 50 on the outermost side on the phase difference layer 30 side as shown in the example of the drawing. By providing the pressure-sensitive adhesive layer in advance, it can be easily bonded to another optical member (for example, a display cell of an image display device). In this case, it is preferable that the release liner 60 is temporarily attached to the surface of the pressure-sensitive adhesive layer 50 to protect the pressure-sensitive adhesive layer 50 until the circularly polarizing plate is used. Furthermore, practically, as for the circularly-polarizing plate 100, the surface protective film 70 may be temporarily attached to the outermost part by the side of the 1st protective layer 11 like the example of illustration. In the present specification, the term “surface protective film” means a film that temporarily protects the circularly polarizing plate during work, and a protective layer of a polarizer such as the first protective layer 11 and the second protective layer 12. It is different from (polarizer protective film).
　円偏光板を構成する各層または光学フィルムは、任意の適切な接着層（接着剤層または粘着剤層）を介して積層されている。接着剤層を構成する接着剤としては、代表的にはポリビニルアルコール系接着剤が挙げられる。粘着剤層を構成する粘着剤としては、代表的にはアクリル系粘着剤が挙げられる。 Each layer or optical film constituting the circularly polarizing plate is laminated via any appropriate adhesive layer (adhesive layer or pressure-sensitive adhesive layer). A typical example of the adhesive constituting the adhesive layer is a polyvinyl alcohol-based adhesive. A typical example of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.
　本発明においては、第２の保護層１２の４０℃、相対湿度９２％における透湿度は１６０ｇ／ｍ２／２４Ｈ未満である。なお、本発明の１つの実施形態においては、第２の保護層１２は省略され、位相差層３０が偏光子２０の保護層を兼ね得る。この場合、位相差層３０の４０℃、相対湿度９２％における透湿度が１６０ｇ／ｍ２／２４Ｈ未満であればよい。すなわち、本発明の実施形態によれば、偏光子２０の表示セル側に隣接する層の透湿度を最適化することにより、状態変化（代表的には、表面保護フィルムの剥離および／またはリリースライナーの剥離）ならびに経時変化のいずれによってもカールが小さい円偏光板を実現することができる。その結果、円偏光板をフレキシブルな画像表示装置に適用した場合に、当該画像表示装置の所望でない屈曲および反りを良好に抑制することができる。すなわち、本発明の実施形態は、フレキシブルな（またはフォルダブルな）画像表示装置に円偏光板を適用して初めて明らかになった課題を解決するものである。これは、フィルムの透湿度はフィルムの構成材料自体の特性およびフィルム厚みの両方に影響されるところ、偏光子の表示セル側に隣接する層（フィルム）に所望される光学特性を維持しつつ、材料および厚みの最適化について試行錯誤を繰り返すことにより得られた、予期せぬ優れた効果である。なお、透湿度は、ＪＩＳ　Ｚ　０２０８（カップ法）に準じて測定され得る。 In the present invention, the moisture permeability of the second protective layer 12 at 40 ° C. and a relative humidity of 92% is less than 160 g / m 2 / 24H. In the embodiment of the present invention, the second protective layer 12 is omitted, and the retardation layer 30 can also serve as the protective layer of the polarizer 20. In this case, the moisture permeability of the retardation layer 30 at 40 ° C. and a relative humidity of 92% may be less than 160 g / m 2 / 24H. That is, according to the embodiment of the present invention, by changing the moisture permeability of the layer adjacent to the display cell side of the polarizer 20, the state change (typically, the peeling of the surface protective film and / or the release liner is performed). A circularly polarizing plate having a small curl can be realized by any of the above-mentioned and peeling over time. As a result, when the circularly polarizing plate is applied to a flexible image display device, undesired bending and warping of the image display device can be satisfactorily suppressed. In other words, the embodiment of the present invention solves the problem that has become apparent for the first time when a circularly polarizing plate is applied to a flexible (or foldable) image display device. This is because the moisture permeability of the film is affected by both the properties of the film constituent material itself and the film thickness, while maintaining the optical properties desired for the layer (film) adjacent to the display cell side of the polarizer, This is an unexpected and excellent effect obtained through repeated trial and error regarding optimization of materials and thickness. The moisture permeability can be measured according to JIS Z 0208 (cup method).
　本発明の実施形態による円偏光板は、（ｉ）リリースライナー６０および表面保護フィルム７０が仮着された状態；（ｉｉ）リリースライナー６０が剥離除去され、表面保護フィルム７０が仮着された状態；ならびに、（ｉｉｉ）リリースライナー６０および表面保護フィルム７０が剥離除去された状態のそれぞれの状態において、２５℃±５℃、相対湿度５５％±１０％の環境下（代表的には、クリーンルーム環境下）に７２時間置いた場合のカール量が、好ましくは±６ｍｍ以内であり、より好ましくは±５ｍｍ以内であり、さらに好ましくは±４ｍｍ以内である。特に、本発明の実施形態による円偏光板は、状態（ｉｉｉ）における経時変化によるカール量が小さいことが特徴である。すなわち、状態（ｉ）および（ｉｉ）におけるカールの制御は従来からなされており、従来の剛直な画像表示装置においては、これらの状態におけるカールの制御のみで十分であった。一方、状態（ｉｉｉ）における経時変化によるカール量を上記範囲とすることにより、フレキシブルな（またはフォルダブルな）画像表示装置自体の屈曲および反りを良好に抑制できることがわかった。上記のように偏光子の表示セル側に隣接する層の透湿度を最適化することにより、状態（ｉｉｉ）における経時変化によるカール量を制御することができる。 In the circularly polarizing plate according to the embodiment of the present invention, (i) the release liner 60 and the surface protective film 70 are temporarily attached; (ii) the release liner 60 is peeled and removed, and the surface protective film 70 is temporarily attached. And (iii) in an environment of 25 ° C. ± 5 ° C. and a relative humidity of 55% ± 10% in each state where the release liner 60 and the surface protection film 70 are peeled and removed (typically, a clean room environment) The curl amount when placed in the lower part for 72 hours is preferably within ± 6 mm, more preferably within ± 5 mm, and even more preferably within ± 4 mm. In particular, the circularly polarizing plate according to the embodiment of the present invention is characterized in that the curl amount due to the change with time in the state (iii) is small. That is, the curl control in the states (i) and (ii) has been conventionally performed, and in the conventional rigid image display device, only the curl control in these states is sufficient. On the other hand, it has been found that by setting the curl amount due to a change with time in the state (iii) within the above range, bending and warping of the flexible (or foldable) image display device itself can be satisfactorily suppressed. By optimizing the moisture permeability of the layer adjacent to the display cell side of the polarizer as described above, it is possible to control the curl amount due to the change with time in the state (iii).
　上記の実施形態は適宜組み合わせてもよく、上記の実施形態における構成要素に当業界で自明の改変を加えてもよい。また、上記実施形態における構成要素を光学的に等価な構成で置き換えてもよい。 The above embodiments may be combined as appropriate, and modifications obvious to those skilled in the art may be added to the components in the above embodiments. Moreover, you may replace the component in the said embodiment with the optically equivalent structure.
　以下、円偏光板の各構成要素について、より詳細に説明する。 Hereinafter, each component of the circularly polarizing plate will be described in more detail.
Ｂ．第１の保護層
　第１の保護層１１は、偏光子の保護層として使用できる任意の適切なフィルムで形成される。当該フィルムの主成分となる材料の具体例としては、トリアセチルセルロース（ＴＡＣ）等のセルロース系樹脂や、ポリエステル系、ポリビニルアルコール系、ポリカーボネート系、ポリアミド系、ポリイミド系、ポリエーテルスルホン系、ポリスルホン系、ポリスチレン系、ポリノルボルネン系、ポリオレフィン系、（メタ）アクリル系、アセテート系等の透明樹脂等が挙げられる。また、（メタ）アクリル系、ウレタン系、（メタ）アクリルウレタン系、エポキシ系、シリコーン系等の熱硬化型樹脂または紫外線硬化型樹脂等も挙げられる。この他にも、例えば、シロキサン系ポリマー等のガラス質系ポリマーも挙げられる。また、特開２００１－３４３５２９号公報（ＷＯ０１／３７００７）に記載のポリマーフィルムも使用できる。このフィルムの材料としては、例えば、側鎖に置換または非置換のイミド基を有する熱可塑性樹脂と、側鎖に置換または非置換のフェニル基ならびにニトリル基を有する熱可塑性樹脂を含有する樹脂組成物が使用でき、例えば、イソブテンとＮ－メチルマレイミドからなる交互共重合体と、アクリロニトリル・スチレン共重合体とを有する樹脂組成物が挙げられる。当該ポリマーフィルムは、例えば、上記樹脂組成物の押出成形物であり得る。 B. First protective layer The first protective layer 11 is formed of any appropriate film that can be used as a protective layer for a polarizer. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As a material for 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 nitrile group in the side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition.
　第１の保護層の厚みは、本発明の効果が得られる限りにおいて、任意の適切な厚みが採用され得る。第１の保護層の厚みは、例えば５μｍ～７０μｍであり、好ましくは１５μｍ～５０μｍである。なお、後述の表面処理が施されている場合、第１の保護層の厚みは、表面処理層の厚みを含めた厚みである。 As the thickness of the first protective layer, any appropriate thickness can be adopted as long as the effect of the present invention is obtained. The thickness of the first protective layer is, for example, 5 μm to 70 μm, preferably 15 μm to 50 μm. In addition, when the below-mentioned surface treatment is performed, the thickness of the first protective layer is a thickness including the thickness of the surface treatment layer.
　本発明の円偏光板は、代表的には画像表示装置の視認側に配置され、第１の保護層１１は、代表的にはその視認側に配置される。したがって、第１の保護層１１には、目的に応じて任意の適切な表面処理が施されていてもよい。１つの実施形態においては、ハードコート処理が行われ、上記のようにハードコート層４０が設けられ得る。ハードコート層を構成する材料としては、例えば、アクリル系樹脂（アクリレート、ウレタンアクリレート）、エポキシ系樹脂を主成分とする紫外線硬化型樹脂が挙げられる。ハードコート層は、このような紫外線硬化型樹脂のモノマーまたはオリゴマーと必要に応じて光重合開始剤およびレベリング剤とを含む溶液を第１の保護層に塗工および乾燥し、当該乾燥した塗工層に光（代表的には紫外線）を照射して硬化させることにより形成され得る。表面処理の別の具体例としては、反射防止処理、スティッキング防止処理、アンチグレア処理が挙げられる。さらに／あるいは、第１の保護層１１には、必要に応じて、偏光サングラスを介して視認する場合の視認性を改善する処理（代表的には、（楕）円偏光機能を付与すること、超高位相差を付与すること）が施されていてもよい。このような処理を施すことにより、偏光サングラス等の偏光レンズを介して表示画面を視認した場合でも、優れた視認性を実現することができる。したがって、円偏光板は、屋外で用いられ得る画像表示装置にも好適に適用され得る。 The circularly polarizing plate of the present invention is typically disposed on the viewing side of the image display device, and the first protective layer 11 is typically disposed on the viewing side. Therefore, the first protective layer 11 may be subjected to any appropriate surface treatment depending on the purpose. In one embodiment, a hard coat process is performed and the hard coat layer 40 may be provided as described above. Examples of the material constituting the hard coat layer include an ultraviolet curable resin mainly composed of an acrylic resin (acrylate, urethane acrylate) and an epoxy resin. The hard coat layer is formed by coating and drying a solution containing such a monomer or oligomer of an ultraviolet curable resin and, if necessary, a photopolymerization initiator and a leveling agent on the first protective layer. It can be formed by irradiating the layer with light (typically ultraviolet rays) and curing. Other specific examples of the surface treatment include antireflection treatment, antisticking treatment, and antiglare treatment. Further / or, if necessary, the first protective layer 11 is provided with a treatment for improving visibility when viewed through polarized sunglasses (typically, imparting an (elliptical) circular polarization function, (Giving an ultrahigh phase difference) may be applied. By performing such processing, excellent visibility can be achieved even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the circularly polarizing plate can be suitably applied to an image display device that can be used outdoors.
Ｃ．偏光子
　偏光子２０としては、任意の適切な偏光子が採用され得る。例えば、偏光子を形成する樹脂フィルムは、単層の樹脂フィルムであってもよく、二層以上の積層体であってもよい。 C. Polarizer Any appropriate polarizer may be adopted as the polarizer 20. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.
　単層の樹脂フィルムから構成される偏光子の具体例としては、ポリビニルアルコール（ＰＶＡ）系フィルム、部分ホルマール化ＰＶＡ系フィルム、エチレン・酢酸ビニル共重合体系部分ケン化フィルム等の親水性高分子フィルムに、ヨウ素や二色性染料等の二色性物質による染色処理および延伸処理が施されたもの、ＰＶＡの脱水処理物やポリ塩化ビニルの脱塩酸処理物等ポリエン系配向フィルム等が挙げられる。好ましくは、光学特性に優れることから、ＰＶＡ系フィルムをヨウ素で染色し一軸延伸して得られた偏光子が用いられる。 Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.
　上記ヨウ素による染色は、例えば、ＰＶＡ系フィルムをヨウ素水溶液に浸漬することにより行われる。上記一軸延伸の延伸倍率は、好ましくは３～７倍である。延伸は、染色処理後に行ってもよいし、染色しながら行ってもよい。また、延伸してから染色してもよい。必要に応じて、ＰＶＡ系フィルムに、膨潤処理、架橋処理、洗浄処理、乾燥処理等が施される。例えば、染色の前にＰＶＡ系フィルムを水に浸漬して水洗することで、ＰＶＡ系フィルム表面の汚れやブロッキング防止剤を洗浄することができるだけでなく、ＰＶＡ系フィルムを膨潤させて染色ムラなどを防止することができる。 The dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution. The stretching 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. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.
　積層体を用いて得られる偏光子の具体例としては、樹脂基材と当該樹脂基材に積層されたＰＶＡ系樹脂層（ＰＶＡ系樹脂フィルム）との積層体、あるいは、樹脂基材と当該樹脂基材に塗布形成されたＰＶＡ系樹脂層との積層体を用いて得られる偏光子が挙げられる。樹脂基材と当該樹脂基材に塗布形成されたＰＶＡ系樹脂層との積層体を用いて得られる偏光子は、例えば、ＰＶＡ系樹脂溶液を樹脂基材に塗布し、乾燥させて樹脂基材上にＰＶＡ系樹脂層を形成して、樹脂基材とＰＶＡ系樹脂層との積層体を得ること；当該積層体を延伸および染色してＰＶＡ系樹脂層を偏光子とすること；により作製され得る。本実施形態においては、延伸は、代表的には積層体をホウ酸水溶液中に浸漬させて延伸することを含む。さらに、延伸は、必要に応じて、ホウ酸水溶液中での延伸の前に積層体を高温（例えば、９５℃以上）で空中延伸することをさらに含み得る。得られた樹脂基材／偏光子の積層体はそのまま用いてもよく（すなわち、樹脂基材を偏光子の保護層としてもよく）、樹脂基材／偏光子の積層体から樹脂基材を剥離し、当該剥離面に目的に応じた任意の適切な保護層を積層して用いてもよい。このような偏光子の製造方法の詳細は、例えば特開２０１２－７３５８０号公報に記載されている。当該公報は、その全体の記載が本明細書に参考として援用される。 As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed 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 and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid 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 layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.
　偏光子の厚みは、好ましくは２５μｍ以下であり、より好ましくは１μｍ～２２μｍであり、さらに好ましくは１μｍ～１２μｍであり、特に好ましくは３μｍ～１２μｍである。偏光子の厚みがこのような範囲であれば、加熱時のカールを良好に抑制することができ、および、良好な加熱時の外観耐久性が得られる。 The thickness of the polarizer is preferably 25 μm or less, more preferably 1 μm to 22 μm, still more preferably 1 μm to 12 μm, and particularly preferably 3 μm to 12 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.
　偏光子は、好ましくは、波長３８０ｎｍ～７８０ｎｍのいずれかの波長で吸収二色性を示す。偏光子の単体透過率は、上記のとおり４３．０％～４６．０％であり、好ましくは４４．５％～４６．０％である。偏光子の偏光度は、好ましくは９７．０％以上であり、より好ましくは９９．０％以上であり、さらに好ましくは９９．９％以上である。 The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. As described above, the single transmittance of the polarizer is 43.0% to 46.0%, preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.
Ｄ．第２の保護層
　第２の保護層１２は、４０℃、相対湿度９２％における透湿度が上記のとおり１６０ｇ／ｍ２／２４Ｈ未満であり、好ましくは１５５ｇ／ｍ２／２４Ｈ以下であり、より好ましくは１５０ｇ／ｍ２／２４Ｈ以下である。透湿度をこのような範囲とすることにより、上記のとおり、状態変化（代表的には、表面保護フィルムの剥離および／またはリリースライナーの剥離）ならびに経時変化のいずれによってもカールが小さい円偏光板を実現することができる。なお、第２の保護層の透湿度の下限は、例えば１０ｇ／ｍ２／２４Ｈである。 D. Second protective layer The second protective layer 12 has a moisture permeability of less than 160 g / m 2 / 24H, preferably 155 g / m 2 / 24H or less, as described above, at 40 ° C. and a relative humidity of 92%. Preferably it is 150 g / m < 2 > / 24H or less. By setting the moisture permeability to such a range, as described above, the circularly polarizing plate has a small curl due to any of the state change (typically peeling of the surface protective film and / or release liner) and change with time. Can be realized. In addition, the minimum of the water vapor transmission rate of a 2nd protective layer is 10 g / m < 2 > / 24H, for example.
　第２の保護層は、上記の透湿度を有し得る限り、偏光子の保護層として使用できる任意の適切なフィルムで形成される。第２の保護層の形成材料として、代表的には、アクリル系樹脂が挙げられる。１つの実施形態においては、アクリル系樹脂として、グルタルイミド構造を有する（メタ）アクリル系樹脂が用いられる。グルタルイミド構造を有する（メタ）アクリル系樹脂は、例えば、特開２００６－３０９０３３号公報、特開２００６－３１７５６０号公報、特開２００６－３２８３２９号公報、特開２００６－３２８３３４号公報、特開２００６－３３７４９１号公報、特開２００６－３３７４９２号公報、特開２００６－３３７４９３号公報、特開２００６－３３７５６９号公報、特開２００７－００９１８２号公報、特開２００９－１６１７４４号公報、特開２０１０－２８４８４０号公報に記載されている。これらの記載は、本明細書に参考として援用される。 The second protective layer is formed of any appropriate film that can be used as a protective layer for the polarizer as long as it can have the above moisture permeability. A typical example of a material for forming the second protective layer is an acrylic resin. In one embodiment, a (meth) acrylic resin having a glutarimide structure is used as the acrylic resin. Examples of the (meth) acrylic resin having a glutarimide structure include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, and JP-A-2006. JP-A-337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, JP-A-2007-009182, JP-A-2009-161744, and JP-A-2010-284840. It is described in the gazette. These descriptions are incorporated herein by reference.
　別の実施形態においては、アクリル系樹脂として、ラクトン環構造を有する（メタ）アクリル系樹脂が用いられる。ラクトン環構造を有する（メタ）アクリル系樹脂は、例えば、特開２０００－２３００１６号公報、特開２００１－１５１８１４号公報、特開２００２－１２０３２６号公報、特開２００２－２５４５４４号公報、特開２００５－１４６０８４号公報に記載されている。これらの記載は、本明細書に参考として援用される。 In another embodiment, a (meth) acrylic resin having a lactone ring structure is used as the acrylic resin. Examples of (meth) acrylic resins having a lactone ring structure include, for example, JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. -146084. These descriptions are incorporated herein by reference.
　上記（メタ）アクリル系樹脂は、Ｔｇ（ガラス転移温度）が、好ましくは１１５℃以上、より好ましくは１２０℃以上、さらに好ましくは１２５℃以上、特に好ましくは１３０℃以上である。耐久性に優れ得るからである。上記（メタ）アクリル系樹脂のＴｇの上限値は特に限定されないが、成形性等の観点から、好ましくは１７０℃以下である。 The (meth) acrylic resin has a Tg (glass transition temperature) of preferably 115 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 125 ° C. or higher, and particularly preferably 130 ° C. or higher. It is because it can be excellent in durability. Although the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From viewpoints of a moldability etc., Preferably it is 170 degrees C or less.
　上記（メタ）アクリル系樹脂は、質量平均分子量（重量平均分子量と称することもある）が、好ましくは１０００～２００００００、より好ましくは５０００～１００００００、さらに好ましくは１００００～５０００００、特に好ましくは５００００～５０００００である。 The (meth) acrylic resin has a mass average molecular weight (sometimes referred to as a weight average molecular weight) of preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, and particularly preferably 50,000 to 500,000. It is.
　第２の保護層１２は、光学的に等方性であることが好ましい。本明細書において「光学的に等方性である」とは、面内位相差Ｒｅ（５５０）が０ｎｍ～１０ｎｍであり、厚み方向の位相差Ｒｔｈ（５５０）が－１０ｎｍ～＋１０ｎｍであることをいう。 The second protective layer 12 is preferably optically isotropic. In this specification, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is −10 nm to +10 nm. Say.
　第２の保護層の厚みは、例えば１５μｍ～３５μｍであり、好ましくは１５μｍ～２５μｍである。このような厚みであれば、偏光子の内側（表示セル側）保護層として所望の光学特性を維持しつつ、上記透湿度を実現することができる。 The thickness of the second protective layer is, for example, 15 μm to 35 μm, preferably 15 μm to 25 μm. With such a thickness, the above moisture permeability can be realized while maintaining desired optical characteristics as a protective layer on the inner side (display cell side) of the polarizer.
Ｅ．位相差層
　位相差層３０は、目的に応じて任意の適切な光学的特性および／または機械的特性を有し得る。位相差層３０は、代表的には遅相軸を有する。位相差層３０の遅相軸と偏光子１１の吸収軸とのなす角度θは、上記のとおり、代表的には３５°～５５°であり、好ましくは３８°～５２°であり、より好ましくは４２°～４８°であり、さらに好ましくは約４５°である。角度θがこのような範囲であれば、位相差層３０を後述のようにλ／４板とすることにより、非常に優れた円偏光特性（結果として、非常に優れた反射防止特性）を有する円偏光板が得られ得る。 E. Retardation layer The retardation layer 30 may have any suitable optical and / or mechanical properties depending on the purpose. The retardation layer 30 typically has a slow axis. As described above, the angle θ formed by the slow axis of the retardation layer 30 and the absorption axis of the polarizer 11 is typically 35 ° to 55 °, preferably 38 ° to 52 °, and more preferably. Is between 42 ° and 48 °, more preferably about 45 °. If the angle θ is in such a range, the retardation layer 30 is a λ / 4 plate as will be described later, thereby having very excellent circular polarization characteristics (as a result, very excellent antireflection characteristics). A circularly polarizing plate can be obtained.
　位相差層３０は、好ましくは屈折率特性がｎｘ＞ｎｙ≧ｎｚの関係を示す。位相差層は、代表的には偏光板に反射防止特性を付与するために設けられ、λ／４板として機能し得る。位相差層の面内位相差Ｒｅ（５５０）は、上記のとおり８０ｎｍ～２００ｎｍであり、好ましくは１００ｎｍ～１８０ｎｍであり、より好ましくは１１０ｎｍ～１７０ｎｍである。なお、ここで「ｎｙ＝ｎｚ」はｎｙとｎｚが完全に等しい場合だけではなく、実質的に等しい場合を包含する。したがって、本発明の効果を損なわない範囲で、ｎｙ＜ｎｚとなる場合があり得る。 The retardation layer 30 preferably has a relationship in refractive index characteristics of nx> ny ≧ nz. The retardation layer is typically provided for imparting antireflection properties to the polarizing plate and can function as a λ / 4 plate. As described above, the in-plane retardation Re (550) of the retardation layer is from 80 nm to 200 nm, preferably from 100 nm to 180 nm, and more preferably from 110 nm to 170 nm. Here, “ny = nz” includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny <nz may be satisfied as long as the effects of the present invention are not impaired.
　位相差層のＮｚ係数は、好ましくは０．９～３、より好ましくは０．９～２．５、さらに好ましくは０．９～１．５、特に好ましくは０．９～１．３である。このような関係を満たすことにより、得られる円偏光板を画像表示装置に用いた場合に、非常に優れた反射色相を達成し得る。 The Nz coefficient of the 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 1.3. . By satisfying such a relationship, when the obtained circularly polarizing plate is used in an image display device, a very excellent reflection hue can be achieved.
　位相差層は、位相差値が測定光の波長に応じて大きくなる逆分散波長特性を示してもよく、位相差値が測定光の波長に応じて小さくなる正の波長分散特性を示してもよく、位相差値が測定光の波長によってもほとんど変化しないフラットな波長分散特性を示してもよい。１つの実施形態においては、位相差層は、逆分散波長特性を示す。この場合、位相差層のＲｅ（４５０）／Ｒｅ（５５０）は、好ましくは０．８以上１未満であり、より好ましくは０．８以上０．９５以下である。このような構成であれば、非常に優れた反射防止特性を実現することができる。別の実施形態においては、位相差層は、フラットな波長分散特性を示す。この場合、位相差層のＲｅ（４５０）／Ｒｅ（５５０）は、好ましくは０.９９～１.０３であり、Ｒｅ（６５０）/Ｒｅ（５５０）は好ましくは０.９８～１.０２である。 The retardation layer may exhibit reverse dispersion wavelength characteristics in which the retardation value increases with the wavelength of the measurement light, or may exhibit positive wavelength dispersion characteristics in which the retardation value decreases with the wavelength of the measurement light. The phase difference value may exhibit a flat chromatic dispersion characteristic that hardly changes depending on the wavelength of the measurement light. In one embodiment, the retardation layer exhibits reverse dispersion wavelength characteristics. 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. In another embodiment, the retardation layer exhibits flat chromatic dispersion characteristics. In this case, Re (450) / Re (550) of the retardation layer is preferably from 0.99 to 1.03, and Re (650) / Re (550) is preferably from 0.98 to 1.02. is there.
　位相差層は、光弾性係数の絶対値が好ましくは２×１０－１１ｍ２／Ｎ以下、より好ましくは２．０×１０－１３ｍ２／Ｎ～１．５×１０－１１ｍ２／Ｎ、さらに好ましくは１．０×１０－１２ｍ２／Ｎ～１．２×１０－１１ｍ２／Ｎの樹脂を含む。光弾性係数の絶対値がこのような範囲であれば、加熱時の収縮応力が発生した場合に位相差変化が生じにくい。その結果、得られる画像表示装置の熱ムラが良好に防止され得る。 Retardation layer, the absolute value of photoelastic coefficient of preferably 2 × 10 -11 m 2 / N or less, more preferably 2.0 × 10 -13 m 2 /N~1.5×10 -11 m 2 / N, more preferably includes a resin of 1.0 × 10 -12 m 2 /N~1.2×10 -11 m 2 / N. When the absolute value of the photoelastic coefficient is in such a range, a phase difference change is unlikely to occur when a shrinkage stress is generated during heating. As a result, heat unevenness of the obtained image display apparatus can be prevented satisfactorily.
　上記のとおり第２の保護層１２が省略されて位相差層３０が偏光子２０の保護層を兼ねる場合、位相差層は、４０℃、相対湿度９２％における透湿度が上記のとおり１６０ｇ／ｍ２／２４Ｈ未満であり、好ましくは１２０ｇ／ｍ２／２４Ｈ以下であり、より好ましくは１００ｇ／ｍ２／２４Ｈ以下である。透湿度をこのような範囲とすることにより、上記のとおり、状態変化（代表的には、表面保護フィルムの剥離および／またはリリースライナーの剥離）ならびに経時変化のいずれによってもカールが小さい円偏光板を実現することができる。なお、位相差層の透湿度の下限は、例えば１０ｇ／ｍ２／２４Ｈである。 As described above, when the second protective layer 12 is omitted and the retardation layer 30 also serves as the protective layer of the polarizer 20, the retardation layer has a moisture permeability of 160 g / m at 40 ° C. and a relative humidity of 92% as described above. It is less than 2 / 24H, preferably 120 g / m 2 / 24H or less, more preferably 100 g / m 2 / 24H or less. By setting the moisture permeability to such a range, as described above, the circularly polarizing plate has a small curl due to any of the state change (typically peeling of the surface protective film and / or release liner) and change with time. Can be realized. In addition, the minimum of the water vapor transmission rate of a phase difference layer is 10 g / m < 2 > / 24H, for example.
　位相差層の厚みは、好ましくは６０μｍ以下であり、好ましくは３０μｍ～５８μｍである。このような厚みであれば、円偏光機能を付与するλ／４板として所望の光学特性を維持しつつ、上記透湿度を実現することができる。 The thickness of the retardation layer is preferably 60 μm or less, and preferably 30 μm to 58 μm. With such a thickness, the above moisture permeability can be realized while maintaining desired optical characteristics as a λ / 4 plate imparting a circularly polarizing function.
　位相差層３０は、上記の特性を満足し得る任意の適切な樹脂フィルムで構成され得る。そのような樹脂の代表例としては、環状オレフィン系樹脂、ポリカーボネート系樹脂、セルロース系樹脂、ポリエステル系樹脂、ポリビニルアルコール系樹脂、ポリアミド系樹脂、ポリイミド系樹脂、ポリエーテル系樹脂、ポリスチレン系樹脂、アクリル系樹脂が挙げられる。位相差層が逆分散波長特性を示す樹脂フィルムで構成される場合、ポリカーボネート系樹脂が好適に用いられ得、フラットな波長分散特性を示す樹脂フィルムで構成される場合、環状オレフィン系樹脂が好適に用いられ得る。 The retardation layer 30 can be composed of any appropriate resin film that can satisfy the above-described characteristics. Typical examples of such resins include cyclic olefin resins, polycarbonate resins, cellulose resins, polyester resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, acrylic resins. Based resins. When the retardation layer is composed of a resin film exhibiting reverse dispersion wavelength characteristics, a polycarbonate-based resin can be suitably used, and when it is composed of a resin film exhibiting flat wavelength dispersion characteristics, a cyclic olefin-based resin is suitable. Can be used.
　上記ポリカーボネート樹脂としては、本発明の効果が得られる限りにおいて、任意の適切なポリカーボネート樹脂を用いることができる。好ましくは、ポリカーボネート樹脂は、フルオレン系ジヒドロキシ化合物に由来する構造単位と、イソソルビド系ジヒドロキシ化合物に由来する構造単位と、脂環式ジオール、脂環式ジメタノール、ジ、トリまたはポリエチレングリコール、ならびに、アルキレングリコールまたはスピログリコールからなる群から選択される少なくとも１つのジヒドロキシ化合物に由来する構造単位と、を含む。好ましくは、ポリカーボネート樹脂は、フルオレン系ジヒドロキシ化合物に由来する構造単位と、イソソルビド系ジヒドロキシ化合物に由来する構造単位と、脂環式ジメタノールに由来する構造単位ならびに／あるいはジ、トリまたはポリエチレングリコールに由来する構造単位と、を含み；さらに好ましくは、フルオレン系ジヒドロキシ化合物に由来する構造単位と、イソソルビド系ジヒドロキシ化合物に由来する構造単位と、ジ、トリまたはポリエチレングリコールに由来する構造単位と、を含む。ポリカーボネート樹脂は、必要に応じてその他のジヒドロキシ化合物に由来する構造単位を含んでいてもよい。なお、本発明に好適に用いられ得るポリカーボネート樹脂の詳細は、例えば、特開２０１４－１０２９１号公報、特開２０１４－２６２６６号公報に記載されており、当該記載は本明細書に参考として援用される。 As the polycarbonate resin, any appropriate polycarbonate resin can be used as long as the effects of the present invention can be obtained. Preferably, the polycarbonate resin includes 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. A structural unit derived from at least one dihydroxy compound selected from the group consisting of glycol or spiroglycol. Preferably, the polycarbonate resin is derived from 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 a di-, tri- or polyethylene glycol. More preferably, a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol. The polycarbonate resin may contain structural units derived from other dihydroxy compounds as necessary. Details of the polycarbonate resin that can be suitably used in the present invention are described in, for example, Japanese Patent Application Laid-Open Nos. 2014-10291 and 2014-26266, and the description is incorporated herein by reference. The
　１つの実施形態においては、オリゴフルオレン構造単位を含むポリカーボネート系樹脂が用いられ得る。オリゴフルオレン構造単位を含むポリカーボネート系樹脂としては、例えば、下記一般式（１）で表される構造単位および／または下記一般式（２）で表される構造単位を含む樹脂が挙げられる。
Figure JPOXMLDOC01-appb-C000001
 （上記一般式（１）および上記一般式（２）中、Ｒ５およびＲ６はそれぞれ独立に、直接結合、置換若しくは無置換の炭素数１～４のアルキレン基（好ましくは、主鎖上の炭素数が２～３であるアルキレン基）である。Ｒ７は、直接結合、置換若しくは無置換の炭素数１～４のアルキレン基（好ましくは、主鎖上の炭素数が１～２であるアルキレン基）である。Ｒ８～Ｒ１３はそれぞれ独立に、水素原子、置換若しくは無置換の炭素数１～１０（好ましくは１～４、より好ましくは１～２）のアルキル基、置換若しくは無置換の炭素数４～１０（好ましくは４～８、より好ましくは４～７）のアリール基、置換若しくは無置換の炭素数１～１０（好ましくは１～４、より好ましくは１～２）のアシル基、置換若しくは無置換の炭素数１～１０（好ましくは１～４、より好ましくは１～２）のアルコキシ基、置換若しくは無置換の炭素数１～１０（好ましくは１～４、より好ましくは１～２）のアリールオキシ基、置換若しくは無置換の炭素数１～１０（好ましくは１～４、より好ましくは１～２）のアシルオキシ基、置換若しくは無置換のアミノ基、置換若しくは無置換の炭素数１～１０（好ましくは１～４）のビニル基、置換若しくは無置換の炭素数１～１０（好ましくは１～４）のエチニル基、置換基を有する硫黄原子、置換基を有するケイ素原子、ハロゲン原子、ニトロ基、またはシアノ基である。Ｒ８～Ｒ１３のうち隣接する少なくとも２つの基が互いに結合して環を形成していてもよい。） In one embodiment, a polycarbonate-based resin containing an oligofluorene structural unit can be used. Examples of the polycarbonate-based resin containing an oligofluorene structural unit include a resin containing a structural unit represented by the following general formula (1) and / or a structural unit represented by the following general formula (2).
Figure JPOXMLDOC01-appb-C000001
 (In the above general formula (1) and the above general formula (2), R 5 and R 6 are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms (preferably on the main chain). R 7 is a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms (preferably having 1 to 2 carbon atoms on the main chain). R 8 to R 13 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted A substituted aryl group having 4 to 10 carbon atoms (preferably 4 to 8, more preferably 4 to 7), a substituted or unsubstituted carbon group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2) Acyl group, substituted or unsubstituted, 1 to 0 (preferably 1 to 4, more preferably 1 to 2) alkoxy group, substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted An unsubstituted acyloxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), a substituted or unsubstituted amino group, and a substituted or unsubstituted carbon atom having 1 to 10 (preferably 1 to 4 carbon atoms); ) A vinyl group, a substituted or unsubstituted ethynyl group having 1 to 10 carbon atoms (preferably 1 to 4), a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group. And at least two adjacent groups out of R 8 to R 13 may be bonded to each other to form a ring.)
　１つの実施形態においては、オリゴフルオレン構造単位に含まれるフルオレン環は、Ｒ８～Ｒ１３の全てが水素原子である構成を有するか、あるいは、Ｒ８及び／又はＲ１３がハロゲン原子、アシル基、ニトロ基、シアノ基、及びスルホ基からなる群から選ばれるいずれかであり、かつ、Ｒ９～Ｒ１２が水素原子である構成を有する。 In one embodiment, the fluorene ring contained in the oligofluorene structural unit has a configuration in which all of R 8 to R 13 are hydrogen atoms, or R 8 and / or R 13 is a halogen atom or an acyl group. , A nitro group, a cyano group, and a sulfo group, and R 9 to R 12 are hydrogen atoms.
　オリゴフルオレン構造単位を含むポリカーボネート系樹脂の詳細は、例えば、特開２０１５－２１２８１６号公報等に記載されている。当該特許文献の記載は、本明細書に参考として援用される。 Details of the polycarbonate-based resin containing the oligofluorene structural unit are described in, for example, JP-A No. 2015-212816. The description of the patent document is incorporated herein by reference.
　前記ポリカーボネート樹脂のガラス転移温度は、１１０℃以上１５０℃以下であることが好ましく、より好ましくは１２０℃以上１４０℃以下である。ガラス転移温度が過度に低いと耐熱性が悪くなる傾向にあり、フィルム成形後に寸法変化を起こす可能性があり、又、得られる有機ＥＬパネルの画像品質を下げる場合がある。ガラス転移温度が過度に高いと、フィルム成形時の成形安定性が悪くなる場合があり、又フィルムの透明性を損なう場合がある。なお、ガラス転移温度は、ＪＩＳ　Ｋ　７１２１（１９８７）に準じて求められる。 The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 150 ° C. or lower, more preferably 120 ° C. or higher and 140 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, there is a possibility of causing a dimensional change after film formation, and the image quality of the resulting organic EL panel may be lowered. If the glass transition temperature is excessively high, the molding stability at the time of film molding may deteriorate, and the transparency of the film may be impaired. The glass transition temperature is determined according to JIS K 7121 (1987).
　前記ポリカーボネート樹脂の分子量は、還元粘度で表すことができる。還元粘度は、溶媒として塩化メチレンを用い、ポリカーボネート濃度を０．６ｇ／ｄＬに精密に調製し、温度２０．０℃±０．１℃でウベローデ粘度管を用いて測定される。還元粘度の下限は、通常０．３０ｄＬ／ｇが好ましく、より好ましくは０．３５ｄＬ／ｇ以上である。還元粘度の上限は、通常１．２０ｄＬ／ｇが好ましく、より好ましくは１．００ｄＬ／ｇ、更に好ましくは０．８０ｄＬ／ｇである。還元粘度が前記下限値より小さいと成形品の機械的強度が小さくなるという問題が生じる場合がある。一方、還元粘度が前記上限値より大きいと、成形する際の流動性が低下し、生産性や成形性が低下するという問題が生じる場合がある。 The molecular weight of the polycarbonate resin can be represented by a reduced viscosity. The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., using methylene chloride as a solvent, precisely adjusting the polycarbonate concentration to 0.6 g / dL. The lower limit of the reduced viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or more. The upper limit of the reduced viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, still more preferably 0.80 dL / g. If the reduced viscosity is less 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, the fluidity at the time of molding is lowered, and there may be a problem that productivity and moldability are lowered.
　ポリカーボネート系樹脂フィルムとして市販のフィルムを用いてもよい。市販品の具体例としては、帝人社製の商品名「ピュアエースＷＲ－Ｓ」、「ピュアエースＷＲ－Ｗ」、「ピュアエースＷＲ－Ｍ」、日東電工社製の商品名「ＮＲＦ」が挙げられる。 A commercially available film may be used as the polycarbonate resin film. Specific examples of commercially available products include “Pure Ace WR-S”, “Pure Ace WR-W”, “Pure Ace WR-M” manufactured by Teijin Limited, and “NRF” manufactured by Nitto Denko Corporation. It is done.
　環状オレフィン系樹脂は、環状オレフィンを重合単位として重合される樹脂の総称であり、例えば、特開平１－２４０５１７号公報、特開平３－１４８８２号公報、特開平３－１２２１３７号公報等に記載されている樹脂が挙げられる。具体例としては、環状オレフィンの開環（共）重合体、環状オレフィンの付加重合体、環状オレフィンとエチレン、プロピレン等のα－オレフィンとの共重合体（代表的には、ランダム共重合体）、および、これらを不飽和カルボン酸やその誘導体で変性したグラフト変性体、ならびに、それらの水素化物が挙げられる。環状オレフィンの具体例としては、ノルボルネン系モノマーが挙げられる。ノルボルネン系モノマーとしては、例えば、ノルボルネン、およびそのアルキルおよび／またはアルキリデン置換体、例えば、５－メチル－２－ノルボルネン、５－ジメチル－２－ノルボルネン、５－エチル－２－ノルボルネン、５－ブチル－２－ノルボルネン、５－エチリデン－２－ノルボルネン等、これらのハロゲン等の極性基置換体；ジシクロペンタジエン、２，３－ジヒドロジシクロペンタジエン等；ジメタノオクタヒドロナフタレン、そのアルキルおよび／またはアルキリデン置換体、およびハロゲン等の極性基置換体、例えば、６－メチル－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－エチル－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－エチリデン－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－クロロ－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－シアノ－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－ピリジル－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン、６－メトキシカルボニル－１，４：５，８－ジメタノ－１，４，４ａ，５，６，７，８，８ａ－オクタヒドロナフタレン等；シクロペンタジエンの３～４量体、例えば、４，９：５，８－ジメタノ－３ａ，４，４ａ，５，８，８ａ，９，９ａ－オクタヒドロ－１Ｈ－ベンゾインデン、４，１１：５，１０：６，９－トリメタノ－３ａ，４，４ａ，５，５ａ，６，９，９ａ，１０，１０ａ，１１，１１ａ－ドデカヒドロ－１Ｈ－シクロペンタアントラセン等が挙げられる。 The cyclic olefin-based resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and α-olefins such as ethylene and propylene (typically random copolymers). And graft modified products in which these are modified with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Specific examples of the cyclic olefin include norbornene monomers. Examples of the norbornene-based monomer include norbornene and alkyl and / or alkylidene substituted products thereof such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl- 2-Norbornene, 5-ethylidene-2-norbornene, etc. Polar group substitution products such as halogens; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, alkyl and / or alkylidene substitution thereof And polar group substituents such as halogen, for example, 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl -1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahi Lonaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5 8-Dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and the like; Tripentamers of cyclopentadiene such as 4,9: 5,8-dimethano-3a, 4 4a, 5,8,8a, 9,9a-Octahydro-1H-benzoindene 4,11: 5,10: 6,9 Torimetano -3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11,11a- dodecahydro -1H- cyclopentadiene anthracene, and the like.
　本発明においては、本発明の目的を損なわない範囲内において、開環重合可能な他のシクロオレフィン類を併用することができる。このようなシクロオレフィンの具体例としては、例えば、シクロペンテン、シクロオクテン、５，６－ジヒドロジシクロペンタジエン等の反応性の二重結合を１個有する化合物が挙げられる。 In the present invention, other cycloolefins capable of ring-opening polymerization can be used in combination as long as the object of the present invention is not impaired. Specific examples of such cycloolefins include compounds having one reactive double bond such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.
　上記環状オレフィン系樹脂は、トルエン溶媒によるゲル・パーミエーション・クロマトグラフ（ＧＰＣ）法で測定した数平均分子量（Ｍｎ）が好ましくは２５，０００～２００，０００、さらに好ましくは３０，０００～１００，０００、最も好ましくは４０，０００～８０，０００である。数平均分子量が上記の範囲であれば、機械的強度に優れ、溶解性、成形性、流延の操作性が良いものができる。 The cyclic olefin resin preferably has a number average molecular weight (Mn) measured by a gel permeation chromatograph (GPC) method using a toluene solvent, preferably 25,000 to 200,000, more preferably 30,000 to 100,000. 000, most preferably 40,000 to 80,000. When the number average molecular weight is in the above range, a material having excellent mechanical strength, good solubility, moldability, and casting operability can be obtained.
　上記環状オレフィン系樹脂フィルムとして市販のフィルムを用いてもよい。具体例としては、日本ゼオン社製の商品名「ゼオネックス」、「ゼオノア」、ＪＳＲ社製の商品名「アートン（Ａｒｔｏｎ）」、ＴＩＣＯＮＡ社製の商品名「トーパス」、三井化学社製の商品名「ＡＰＥＬ」が挙げられる。 A commercially available film may be used as the cyclic olefin resin film. Specific examples include trade names “ZEONEX” and “ZEONOR” manufactured by ZEON CORPORATION, “Arton” manufactured by JSR, “TOPAS” trade name manufactured by TICONA, and trade names manufactured by Mitsui Chemicals, Inc. “APEL” may be mentioned.
　位相差層３０は、例えば、上記樹脂から形成されたフィルムを延伸することにより得られる。樹脂からフィルムを形成する方法としては、任意の適切な成形加工法が採用され得る。具体例としては、圧縮成形法、トランスファー成形法、射出成形法、押出成形法、ブロー成形法、粉末成形法、ＦＲＰ成形法、キャスト塗工法（例えば、流延法）、カレンダー成形法、熱プレス法等が挙げられる。押出成形法またはキャスト塗工法が好ましい。得られるフィルムの平滑性を高め、良好な光学的均一性を得ることができるからである。成形条件は、使用される樹脂の組成や種類、位相差層に所望される特性等に応じて適宜設定され得る。なお、上記のとおり、ポリカーボネート系樹脂または環状オレフィン系樹脂は、多くのフィルム製品が市販されているので、当該市販フィルムをそのまま延伸処理に供してもよい。 The retardation layer 30 is obtained, for example, by stretching a film formed from the resin. Any appropriate forming method can be adopted as a method of forming a film from a resin. Specific examples include compression molding methods, transfer molding methods, injection molding methods, extrusion molding methods, blow molding methods, powder molding methods, FRP molding methods, cast coating methods (for example, casting methods), calendar molding methods, and hot presses. Law. Extrusion molding or cast coating is preferred. This is because the smoothness of the resulting 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 properties desired for the retardation layer, and the like. In addition, as above-mentioned, since many film products are marketed for polycarbonate-type resin or cyclic olefin-type resin, you may use the said commercial film as it is for a extending | stretching process.
　樹脂フィルム（未延伸フィルム）の厚みは、位相差層の所望の厚み、所望の光学特性、後述の延伸条件などに応じて、任意の適切な値に設定され得る。好ましくは５０μｍ～３００μｍである。 The thickness of the resin film (unstretched film) can be set to any appropriate value depending on the desired thickness of the retardation layer, the desired optical properties, the stretching conditions described below, and the like. The thickness is preferably 50 μm to 300 μm.
　上記延伸は、任意の適切な延伸方法、延伸条件（例えば、延伸温度、延伸倍率、延伸方向）が採用され得る。具体的には、自由端延伸、固定端延伸、自由端収縮、固定端収縮などの様々な延伸方法を、単独で用いることも、同時もしくは逐次で用いることもできる。延伸方向に関しても、長さ方向、幅方向、厚さ方向、斜め方向等、様々な方向や次元に行なうことができる。 Any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) may be employed 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 singly or simultaneously or sequentially. The stretching direction can also be performed in various directions and dimensions such as a length direction, a width direction, a thickness direction, and an oblique direction.
　１つの実施形態においては、位相差フィルムは、樹脂フィルムを一軸延伸もしくは固定端一軸延伸することにより作製される。固定端一軸延伸の具体例としては、樹脂フィルムを長手方向に走行させながら、幅方向（横方向）に延伸する方法が挙げられる。延伸倍率は、好ましくは１．１倍～３．５倍である。 In one embodiment, the retardation film is produced by uniaxially stretching a resin film or uniaxially stretching a fixed end. As a specific example of the fixed end uniaxial stretching, there is a method of stretching in the width direction (lateral direction) while running the resin film in the longitudinal direction. The draw ratio is preferably 1.1 to 3.5 times.
　別の実施形態においては、位相差フィルムは、長尺状の樹脂フィルムを長手方向に対して上記の角度θの方向に連続的に斜め延伸することにより作製され得る。斜め延伸を採用することにより、フィルムの長手方向に対して角度θの配向角（角度θの方向に遅相軸）を有する長尺状の延伸フィルムが得られ、例えば、偏光子との積層に際してロールトゥロールが可能となり、製造工程を簡略化することができる。なお、角度θは、円偏光板において偏光子の吸収軸と位相差層の遅相軸とがなす角度であり得る。角度θは、上記のとおり、代表的には３５°～５５°であり、好ましくは３８°～５２°であり、より好ましくは４２°～４８°であり、さらに好ましくは約４５°である。 In another embodiment, the retardation film can be produced by continuously stretching a long resin film obliquely in the direction of the angle θ described above with respect to the longitudinal direction. By adopting oblique stretching, a long stretched film having an orientation angle of θ with respect to the longitudinal direction of the film (slow axis in the direction of angle θ) can be obtained. For example, when laminating with a polarizer Roll-to-roll is possible, and the manufacturing process can be simplified. The angle θ may be an angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer in the circularly polarizing plate. As described above, the angle θ is typically 35 ° to 55 °, preferably 38 ° to 52 °, more preferably 42 ° to 48 °, and further preferably about 45 °.
　斜め延伸に用いる延伸機としては、例えば、横および／または縦方向に、左右異なる速度の送り力もしくは引張り力または引き取り力を付加し得るテンター式延伸機が挙げられる。テンター式延伸機には、横一軸延伸機、同時二軸延伸機等があるが、長尺状の樹脂フィルムを連続的に斜め延伸し得る限り、任意の適切な延伸機が用いられ得る。 Examples of the stretching machine used for the oblique stretching include a tenter type stretching machine capable of adding feed forces, pulling forces, or pulling forces at different speeds in the lateral and / or longitudinal 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 a long resin film can be continuously stretched obliquely.
　上記延伸機において左右の速度をそれぞれ適切に制御することにより、上記所望の面内位相差を有し、かつ、上記所望の方向に遅相軸を有する位相差層（実質的には、長尺状の位相差フィルム）が得られ得る。 By appropriately controlling the left and right velocities in the stretching machine, the retardation layer having the desired in-plane retardation and having the slow axis in the desired direction (substantially long) Shaped retardation film) can be obtained.
　上記フィルムの延伸温度は、位相差層に所望される面内位相差値および厚み、使用される樹脂の種類、使用されるフィルムの厚み、延伸倍率等に応じて変化し得る。具体的には、延伸温度は、好ましくはＴｇ－３０℃～Ｔｇ＋６０℃、さらに好ましくはＴｇ－１５℃～Ｔｇ＋５５℃、最も好ましくはＴｇ－１０℃～Ｔｇ＋５０℃である。このような温度で延伸することにより、本発明において適切な特性を有する第１の位相差層が得られ得る。なお、Ｔｇは、フィルムの構成材料のガラス転移温度である。 The stretching temperature of the film can vary 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 + 60 ° C, more preferably Tg-15 ° C to Tg + 55 ° C, and most preferably Tg-10 ° C to Tg + 50 ° C. By extending | stretching at such temperature, the 1st phase difference layer which has a suitable characteristic in this invention can be obtained. Tg is the glass transition temperature of the constituent material of the film.
　上記延伸方法、延伸条件を適宜選択することにより、上記所望の光学特性（例えば、屈折率特性、面内位相差、Ｎｚ係数）を有する位相差フィルムを得ることができる。 A retardation film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained by appropriately selecting the stretching method and stretching conditions.
Ｆ．導電層または導電層付等方性基材
　導電層は、任意の適切な成膜方法（例えば、真空蒸着法、スパッタリング法、ＣＶＤ法、イオンプレーティング法、スプレー法等）により、任意の適切な基材上に、金属酸化物膜を成膜して形成され得る。金属酸化物としては、例えば、酸化インジウム、酸化スズ、酸化亜鉛、インジウム－スズ複合酸化物、スズ－アンチモン複合酸化物、亜鉛－アルミニウム複合酸化物、インジウム－亜鉛複合酸化物が挙げられる。なかでも好ましくは、インジウム－スズ複合酸化物（ＩＴＯ）である。 F. Conductive layer or isotropic substrate with conductive layer The conductive layer can be formed by any suitable film formation method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). A metal oxide film can be formed thereon. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.
　導電層が金属酸化物を含む場合、該導電層の厚みは、好ましくは５０ｎｍ以下であり、より好ましくは３５ｎｍ以下である。導電層の厚みの下限は、好ましくは１０ｎｍである。 When the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.
　導電層は、上記基材から位相差層に転写されて導電層単独で円偏光板の構成層とされてもよく、基材との積層体（導電層付基材）として位相差層に積層されてもよい。好ましくは、上記基材は光学的に等方性であり、したがって、導電層は導電層付等方性基材として円偏光板に用いられ得る。 The conductive layer may be transferred from the base material to the retardation layer, and the conductive layer alone may be a constituent layer of a circularly polarizing plate, and is laminated on the retardation layer as a laminate (base material with a conductive layer) with the base material. May be. Preferably, the base material is optically isotropic, and therefore the conductive layer can be used for a circularly polarizing plate as an isotropic base material with a conductive layer.
　光学的に等方性の基材（等方性基材）としては、任意の適切な等方性基材を採用し得る。等方性基材を構成する材料としては、例えば、ノルボルネン系樹脂やオレフィン系樹脂などの共役系を有さない樹脂を主骨格としている材料、ラクトン環やグルタルイミド環などの環状構造をアクリル系樹脂の主鎖中に有する材料などが挙げられる。このような材料を用いると、等方性基材を形成した際に、分子鎖の配向に伴う位相差の発現を小さく抑えることができる。等方性基材の厚みは、好ましくは５０μｍ以下であり、より好ましくは３５μｍ以下である。等方性基材の厚みの下限は、例えば２０μｍである。 As the optically isotropic substrate (isotropic substrate), any appropriate isotropic substrate can be adopted. As a material constituting the isotropic substrate, for example, a material having a main skeleton such as a norbornene resin or an olefin resin as a main skeleton, or a cyclic structure such as a lactone ring or a glutarimide ring is used for an acrylic resin. Examples thereof include materials possessed in the main chain. When such a material is used, when an isotropic substrate is formed, it is possible to suppress the expression of the phase difference accompanying the orientation of the molecular chain. The thickness of the isotropic substrate is preferably 50 μm or less, more preferably 35 μm or less. The lower limit of the thickness of the isotropic substrate is, for example, 20 μm.
　上記導電層および／または上記導電層付等方性基材の導電層は、必要に応じてパターン化され得る。パターン化によって、導通部と絶縁部とが形成され得る。結果として、電極が形成され得る。電極は、タッチパネルへの接触を感知するタッチセンサ電極として機能し得る。パターニング方法としては、任意の適切な方法を採用し得る。パターニング方法の具体例としては、ウエットエッチング法、スクリーン印刷法が挙げられる。 The conductive layer and / or the conductive layer of the isotropic base material with the conductive layer may be patterned as necessary. By conducting the patterning, a conductive portion and an insulating portion can be formed. As a result, an electrode can be formed. The electrode can function as a touch sensor electrode that senses contact with the touch panel. Any appropriate method can be adopted as the patterning method. Specific examples of the patterning method include a wet etching method and a screen printing method.
Ｇ．画像表示装置
　上記Ａ項からＦ項に記載の円偏光板は、フレキシブルな画像表示装置に適用され得る。したがって、本発明は、そのような円偏光板を用いたフレキシブルな画像表示装置を包含する。フレキシブルな画像表示装置の代表例としては、有機ＥＬ表示装置が挙げられる。本発明の実施形態によるフレキシブルな画像表示装置は、その視認側に上記Ａ項からＦ項に記載の円偏光板を備える。円偏光板は、位相差層が表示セル（例えば、有機ＥＬセル）側となるように（偏光子が視認側となるように）積層されている。 G. Image Display Device The circularly polarizing plate described in the items A to F can be applied to a flexible image display device. Therefore, the present invention includes a flexible image display device using such a circularly polarizing plate. A typical example of a flexible image display device is an organic EL display device. The flexible image display apparatus by embodiment of this invention is equipped with the circularly-polarizing plate as described in said A term to F term in the visual recognition side. The circularly polarizing plate is laminated so that the retardation layer is on the display cell (for example, organic EL cell) side (so that the polarizer is on the viewing side).
　フレキシブルな有機ＥＬ表示装置は、例えば、有機ＥＬセルの基板をフレキシブルまたはフォルダブルな材料で構成することにより実現され得る。そのような材料としては、代表的には、可撓性を付与した薄ガラス、熱可塑性樹脂または熱硬化性樹脂フィルム、合金、金属が挙げられる。熱可塑性樹脂または熱硬化性樹脂としては、例えば、ポリエステル系樹脂、ポリイミド系樹脂、エポキシ系樹脂、ポリウレタン系樹脂、ポリスチレン系樹脂、ポリオレフィン系樹脂、ポリアミド系樹脂、ポリカーボネート系樹脂、シリコーン系樹脂、フッ素系樹脂、アクリロニトリル－ブタジエン－スチレン共重合体樹脂が挙げられる。合金としては、例えば、ステンレス、３６アロイ、４２アロイが挙げられる。金属としては、例えば、銅、ニッケル、鉄、アルミニウム、チタンが挙げられる。 A flexible organic EL display device can be realized, for example, by configuring a substrate of an organic EL cell with a flexible or foldable material. As such a material, typically, thin glass provided with flexibility, a thermoplastic resin or a thermosetting resin film, an alloy, and a metal can be given. Examples of the thermoplastic resin or thermosetting resin include polyester resins, polyimide resins, epoxy resins, polyurethane resins, polystyrene resins, polyolefin resins, polyamide resins, polycarbonate resins, silicone resins, fluorine And acrylonitrile-butadiene-styrene copolymer resin. Examples of the alloy include stainless steel, 36 alloy, and 42 alloy. Examples of the metal include copper, nickel, iron, aluminum, and titanium.
　有機ＥＬ表示装置の構成は業界で周知であるので、詳細な説明は省略する。なお、フレキシブルまたはフォルダブルな有機ＥＬ表示装置の詳細は、例えば、特許第４６０１４６３号または特許第４７０７９９６号に記載されている。これらの記載は、参考として本明細書に援用される。 Since the configuration of the organic EL display device is well known in the industry, detailed description is omitted. Details of the flexible or foldable organic EL display device are described in, for example, Japanese Patent No. 4601463 or Japanese Patent No. 4707996. These descriptions are incorporated herein by reference.
　以下、実施例によって本発明を具体的に説明するが、本発明はこれら実施例によって限定されるものではない。なお、各特性の測定方法は以下の通りである。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic is as follows.
（１）厚み
　デジタルマイクロメーター（アンリツ社製ＫＣ－３５１Ｃ）を用いて測定した。
（２）位相差層の位相差値
　実施例および比較例で用いた位相差層の屈折率ｎｘ、ｎｙおよびｎｚを、自動複屈折測定装置（王子計測機器株式会社製，自動複屈折計ＫＯＢＲＡ－ＷＰＲ）により計測した。面内位相差Ｒｅの測定波長は４５０ｎｍおよび５５０ｎｍであり、厚み方向位相差Ｒｔｈの測定波長は５５０ｎｍであり、測定温度は２３℃であった。
（３）透湿度
　第２の保護層または位相差層を構成するフィルムについて、ＪＩＳ　Ｚ　０２０８（カップ法）に準じて測定した。
（４）カール量
　実施例および比較例で得られた円偏光板について、（ｉ）リリースライナーおよび表面保護フィルムが仮着された状態；（ｉｉ）リリースライナーが剥離除去され、表面保護フィルムが仮着された状態；ならびに、（ｉｉｉ）リリースライナーおよび表面保護フィルムが剥離除去された状態のそれぞれの状態において、２５℃±５℃、クリーンルーム（相対湿度５５％±１０％）環境下に７２時間置いた場合のカール量を測定した。具体的には、静電気の発生しない土台上に、円偏光板をその中央部が台座に接するよう静置し、７２時間後の円偏光板の反りを鋼製金尺により測定し、４隅の反りのうち最も高いものをカール量とした。さらに、円偏光板が第１の保護層側（ハードコート層側）に反る場合を「プラス」、第２の保護層側（粘着剤層側）に反る場合を「マイナス」とした。カール量が±６ｍｍ以内である場合を「良好」、６ｍｍを超える場合を「不良」とした。 (1) Thickness The thickness was measured using a digital micrometer (KC-351C manufactured by Anritsu).
(2) Retardation value of retardation layer Refractive index nx, ny and nz of the retardation layer used in the examples and comparative examples were determined using an automatic birefringence measuring device (manufactured by Oji Scientific Instruments, automatic birefringence meter KOBRA- WPR). The measurement wavelength of the in-plane retardation Re was 450 nm and 550 nm, the measurement wavelength of the thickness direction retardation Rth was 550 nm, and the measurement temperature was 23 ° C.
(3) Moisture permeability The film constituting the second protective layer or retardation layer was measured according to JIS Z 0208 (cup method).
(4) Curling amount For the circularly polarizing plates obtained in the examples and comparative examples, (i) the release liner and the surface protective film are temporarily attached; (ii) the release liner is peeled and removed, and the surface protective film is temporarily And (iii) in a state where the release liner and the surface protective film are peeled and removed, each is placed in a clean room (relative humidity 55% ± 10%) environment for 72 hours. The curl amount was measured. Specifically, the circularly polarizing plate is allowed to stand on a base where static electricity is not generated so that the central part thereof is in contact with the pedestal, and the warpage of the circularly polarizing plate after 72 hours is measured with a steel metal ruler. The highest amount of warpage was taken as the curl amount. Furthermore, the case where the circularly polarizing plate warps to the first protective layer side (hard coat layer side) is “plus”, and the case where the circularly polarizing plate warps to the second protective layer side (adhesive layer side) is “minus”. The case where the curl amount was within ± 6 mm was determined as “good”, and the case where the curl amount exceeded 6 mm was determined as “bad”.
［参考例１：偏光板の作製］
　厚み６０μｍのポリビニルアルコール（ＰＶＡ）系樹脂フィルム（クラレ社製、製品名「ＰＥ６０００」）の長尺ロールを、ロール延伸機により長尺方向に５．９倍になるように長尺方向に一軸延伸しながら同時に膨潤、染色、架橋、洗浄処理を施し、最後に乾燥処理を施すことにより厚み２２μｍの偏光子１を作製した。
　具体的には、膨潤処理は２０℃の純水で処理しながら２．２倍に延伸した。次いで、染色処理は得られる偏光子の単体透過率が４５．０％になるようにヨウ素濃度が調整されたヨウ素とヨウ化カリウムの重量比が１：７である３０℃の水溶液中において処理しながら１．４倍に延伸した。更に、架橋処理は、２段階の架橋処理を採用し、１段階目の架橋処理は４０℃のホウ酸とヨウ化カリウムを溶解した水溶液において処理しながら１．２倍に延伸した。１段階目の架橋処理の水溶液のホウ酸含有量は５．０重量％で、ヨウ化カリウム含有量は３．０重量％とした。２段階目の架橋処理は６５℃のホウ酸とヨウ化カリウムを溶解した水溶液において処理しながら１．６倍に延伸した。２段階目の架橋処理の水溶液のホウ酸含有量は４．３重量％で、ヨウ化カリウム含有量は５．０重量％とした。また、洗浄処理は、２０℃のヨウ化カリウム水溶液で処理した。洗浄処理の水溶液のヨウ化カリウム含有量は２．６重量％とした。最後に、乾燥処理は７０℃で５分間乾燥させて偏光子１を得た。
　得られた偏光子１の両面に、ポリビニルアルコール系接着剤を介して、グルタルイミド環構造を有するメタクリル樹脂フィルム（厚み：２０μｍ、第２の保護層に対応する）及びＴＡＣフィルムの片面にハードコート処理により形成されたハードコート（ＨＣ）層を有するＨＣ－ＴＡＣフィルム（厚み：４７μｍ、第１の保護層に対応する）をそれぞれ貼り合わせて、第１の保護層／偏光子１／第２の保護層の構成を有する偏光板１を得た。
　なお、グルタルイミド環構造を有するメタクリル樹脂フィルムは、以下のようにして作製した。グルタルイミド環構造を有するメタクリル樹脂ペレットを、１００．５ｋＰａ、１００℃で１２時間乾燥させ、単軸の押出機にてダイス温度２７０℃でＴダイから押し出してフィルム状に成形した。得られたフィルムを、その搬送方向（ＭＤ）に、上記樹脂のガラス転移温度Ｔｇよりも１０℃高い雰囲気下で延伸し、次いで、搬送方向と直交する方向（ＴＤ）に、上記樹脂のガラス転移温度Ｔｇよりも７℃高い雰囲気下で延伸した。得られたフィルムは、実質的に光学的に等方性を示していた。 [Reference Example 1: Production of polarizing plate]
A long roll of polyvinyl alcohol (PVA) resin film (product name “PE6000”, manufactured by Kuraray Co., Ltd.) having a thickness of 60 μm is uniaxially stretched in the longitudinal direction so as to be 5.9 times in the longitudinal direction by a roll stretching machine. At the same time, swelling, dyeing, crosslinking, and washing treatment were performed, and finally, a drying treatment was performed to prepare a polarizer 1 having a thickness of 22 μm.
Specifically, the swelling treatment was stretched 2.2 times while being treated with pure water at 20 ° C. Next, the dyeing treatment is performed in an aqueous solution at 30 ° C. in which the weight ratio of iodine and potassium iodide is 1: 7, the iodine concentration of which is adjusted so that the single transmittance of the obtained polarizer is 45.0%. The film was stretched 1.4 times. Furthermore, the crosslinking treatment employed a two-stage crosslinking treatment, and the first-stage crosslinking treatment was stretched 1.2 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 40 ° C. The boric acid content of the aqueous solution of the first-stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. The cross-linking treatment at the second stage was stretched 1.6 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C. The boric acid content of the aqueous solution of the second crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. In addition, the cleaning treatment was performed with an aqueous potassium iodide solution at 20 ° C. The potassium iodide content of the aqueous solution for the washing treatment was 2.6% by weight. Finally, the drying process was performed at 70 ° C. for 5 minutes to obtain a polarizer 1.
A methacrylic resin film having a glutarimide ring structure (thickness: 20 μm, corresponding to the second protective layer) and a TAC film are hard coated on both sides of the obtained polarizer 1 via a polyvinyl alcohol adhesive. HC-TAC films (thickness: 47 μm, corresponding to the first protective layer) each having a hard coat (HC) layer formed by the treatment were bonded together, and the first protective layer / polarizer 1 / second The polarizing plate 1 which has the structure of a protective layer was obtained.
In addition, the methacrylic resin film which has a glutarimide ring structure was produced as follows. The methacrylic resin pellets having a glutarimide ring structure were dried at 100.5 kPa and 100 ° C. for 12 hours, and extruded from a T-die at a die temperature of 270 ° C. with a single screw extruder to form a film. The obtained film is stretched in the transport direction (MD) in an atmosphere 10 ° C. higher than the glass transition temperature Tg of the resin, and then the glass transition of the resin in the direction (TD) orthogonal to the transport direction. The film was stretched in an atmosphere 7 ° C. higher than the temperature Tg. The resulting film was substantially optically isotropic.
［参考例２：偏光板の作製］
　厚み３０μｍのポリビニルアルコール（ＰＶＡ）系樹脂フィルム（クラレ製、製品名「ＰＥ３０００」）の長尺ロールを、ロール延伸機により長尺方向に５．９倍になるように長尺方向に一軸延伸しながら同時に膨潤、染色、架橋、洗浄処理を施し、最後に乾燥処理を施すことにより厚み１２μｍの偏光子２を作製した。得られた偏光子２の片面に、ポリビニルアルコール系接着剤を介して、ポリカーボネート系樹脂フィルムの片面にハードコート処理により形成されたハードコート（ＨＣ）層を有するＨＣ－ＰＣフィルム（厚み：２５μｍ、第１の保護層に対応する）を貼り合わせて、第１の保護層／偏光子２の構成を有する偏光板２を得た。 [Reference Example 2: Preparation of polarizing plate]
A long roll of polyvinyl alcohol (PVA) resin film (product name “PE3000”, manufactured by Kuraray Co., Ltd.) having a thickness of 30 μm is uniaxially stretched in the longitudinal direction so that it becomes 5.9 times in the longitudinal direction by a roll stretching machine. At the same time, swelling, dyeing, crosslinking, and washing treatment were performed, and finally, a drying treatment was performed to produce a polarizer 2 having a thickness of 12 μm. An HC-PC film (thickness: 25 μm, having a hard coat (HC) layer formed on one side of the polycarbonate resin film on one side of the obtained polarizer 2 via a polyvinyl alcohol adhesive by a hard coat treatment. The polarizing plate 2 having the configuration of the first protective layer / polarizer 2 was obtained.
［参考例３：偏光板の作製］
　参考例２で得られた偏光子２の両面に、ポリビニルアルコール系接着剤を介して、コニカミノルタ株式会社製のＴＡＣフィルム（製品名：ＫＣ２ＵＡ、厚み：２５μｍ、第２の保護層に対応する）及び当該ＴＡＣフィルムの片面にハードコート処理により形成されたハードコート（ＨＣ）層を有するＨＣ－ＴＡＣフィルム（厚み：３２μｍ、第１の保護層に対応する）をそれぞれ貼り合わせて、第１の保護層／偏光子２／第２の保護層の構成を有する偏光板３を得た。 [Reference Example 3: Production of Polarizing Plate]
A TAC film manufactured by Konica Minolta Co., Ltd. (product name: KC2UA, thickness: 25 μm, corresponding to the second protective layer) on both sides of the polarizer 2 obtained in Reference Example 2 via a polyvinyl alcohol-based adhesive. And an HC-TAC film (thickness: 32 μm, corresponding to the first protective layer) having a hard coat (HC) layer formed on one side of the TAC film by a hard coat treatment, respectively, for the first protection A polarizing plate 3 having a configuration of layer / polarizer 2 / second protective layer was obtained.
［参考例４：偏光板の作製］
　第２の保護層としてコニカミノルタ社製のＴＡＣフィルム（製品名：ＫＣ２ＣＴ１、厚み：２０μｍ）を用いたこと以外は参考例１と同様にして、第１の保護層／偏光子１／第２の保護層の構成を有する偏光板４を得た。 [Reference Example 4: Production of Polarizing Plate]
The first protective layer / polarizer 1 / second in the same manner as in Reference Example 1 except that a TAC film manufactured by Konica Minolta (product name: KC2CT1, thickness: 20 μm) was used as the second protective layer. A polarizing plate 4 having a protective layer configuration was obtained.
［参考例５：偏光板の作製］
　厚み６０μｍのポリビニルアルコール（ＰＶＡ）系樹脂フィルム（クラレ製、製品名「ＰＥ６０００」）の長尺ロールを、ロール延伸機により長尺方向に５．９倍になるように長尺方向に一軸延伸しながら同時に膨潤、染色、架橋、洗浄処理を施し、最後に乾燥処理を施すことにより厚み２３μｍの偏光子３を作製した。得られた偏光子３の片面に、ポリビニルアルコール系接着剤を介して、ＴＡＣフィルムの片面に低反射ハードコート処理により形成されたハードコート（ＨＣ）層を有する低反射ＴＡＣフィルム（厚み：７１μｍ、第１の保護層に対応する；大日本印刷株式会社製、製品名「ＤＳＧ－０３ＨＬ」）を貼り合わせて、第１の保護層／偏光子３の構成を有する偏光板５を得た。 [Reference Example 5: Production of polarizing plate]
A 60 μm thick polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name “PE6000”) is uniaxially stretched in the longitudinal direction by a roll stretching machine so as to be 5.9 times in the longitudinal direction. At the same time, swelling, dyeing, crosslinking, and washing treatment were performed, and finally a drying treatment was performed to produce a polarizer 3 having a thickness of 23 μm. A low-reflection TAC film (thickness: 71 μm, having a hard coat (HC) layer formed on one side of the TAC film on one side of the obtained polarizer 3 through a polyvinyl alcohol-based adhesive by a low-reflection hard coat treatment. The polarizing plate 5 corresponding to the first protective layer; manufactured by Dai Nippon Printing Co., Ltd., product name “DSG-03HL”) was bonded to obtain the polarizing plate 5 having the first protective layer / polarizer 3 configuration.
［参考例６：位相差層を構成する位相差フィルムの作製］
１．ポリカーボネート樹脂フィルムの作製
　イソソルビド（ＩＳＢ）２６．２質量部、９，９－［４－（２－ヒドロキシエトキシ）フェニル］フルオレン（ＢＨＥＰＦ）１００．５質量部、１，４－シクロヘキサンジメタノール（１，４－ＣＨＤＭ）１０．７質量部、ジフェニルカーボネート（ＤＰＣ）１０５．１質量部、および、触媒として炭酸セシウム（０．２質量％水溶液）０．５９１質量部をそれぞれ反応容器に投入し、窒素雰囲気下にて、反応の第１段目の工程として、反応容器の熱媒温度を１５０℃にし、必要に応じて攪拌しながら、原料を溶解させた（約１５分）。
　次いで、反応容器内の圧力を常圧から１３．３ｋＰａにし、反応容器の熱媒温度を１９０℃まで１時間で上昇させながら、発生するフェノールを反応容器外へ抜き出した。
　反応容器内温度を１９０℃で１５分保持した後、第２段目の工程として、反応容器内の圧力を６．６７ｋＰａとし、反応容器の熱媒温度を２３０℃まで、１５分で上昇させ、発生するフェノールを反応容器外へ抜き出した。攪拌機の攪拌トルクが上昇してくるので、８分で２５０℃まで昇温し、さらに発生するフェノールを取り除くため、反応容器内の圧力を０．２００ｋＰａ以下に減圧した。所定の攪拌トルクに到達後、反応を終了し、生成した反応物を水中に押し出した後に、ペレット化を行い、ＢＨＥＰＦ／ＩＳＢ／１，４－ＣＨＤＭ＝４７．４モル％／３７．１モル％／１５．５モル％のポリカーボネート樹脂を得た。
　得られたポリカーボネート樹脂のガラス転移温度は１３６．６℃であり、還元粘度は０．３９５ｄＬ／ｇであった。
　得られたポリカーボネート樹脂を８０℃で５時間真空乾燥をした後、単軸押出機（いすず化工機社製、スクリュー径２５ｍｍ、シリンダー設定温度：２２０℃）、Ｔダイ（幅２００ｍｍ、設定温度：２２０℃）、チルロール（設定温度：１２０～１３０℃）および巻取機を備えたフィルム製膜装置を用いて、厚み１２０μｍのポリカーボネート樹脂フィルムを作製した。 [Reference Example 6: Production of retardation film constituting retardation layer]
1. Preparation of Polycarbonate Resin Film Isosorbide (ISB) 26.2 parts by mass, 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF) 100.5 parts by mass, 1,4-cyclohexanedimethanol (1, 4-CHDM) 10.7 parts by mass, diphenyl carbonate (DPC) 105.1 parts by mass, and cesium carbonate (0.2% by mass aqueous solution) 0.591 parts by mass as a catalyst were put in a reaction vessel, respectively, and a nitrogen atmosphere Below, as a first step of the reaction, the temperature of the heating medium in the reaction vessel was set to 150 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes).
Next, the pressure in the reaction vessel was changed from normal pressure to 13.3 kPa, and the generated phenol was extracted out of the reaction vessel while the temperature of the heat medium in the reaction vessel was increased to 190 ° C. over 1 hour.
After holding the reaction vessel temperature at 190 ° C. for 15 minutes, as a second step, the pressure in the reaction vessel is set to 6.67 kPa, and the heat medium temperature of the reaction vessel is increased to 230 ° C. in 15 minutes. The generated phenol was extracted out of the reaction vessel. Since the stirring torque of the stirrer increased, the temperature was raised to 250 ° C. in 8 minutes, and the pressure in the reaction vessel was reduced to 0.200 kPa or less in order to remove the generated phenol. After reaching a predetermined stirring torque, the reaction was terminated, and the reaction product formed was extruded into water, and then pelletized to obtain BHEPF / ISB / 1,4-CHDM = 47.4 mol% / 37.1 mol%. /15.5 mol% polycarbonate resin was obtained.
The obtained polycarbonate resin had a glass transition temperature of 136.6 ° C. and a reduced viscosity of 0.395 dL / g.
The obtained polycarbonate resin was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (made by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 200 mm, set temperature: 220). ° C.), a chill roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winder, a 120 μm thick polycarbonate resin film was produced.
２．位相差フィルムの作製
　テンター延伸機を用いて、得られたポリカーボネート樹脂フィルムを横延伸し、厚み５０μｍの位相差フィルムを得た。その際、延伸倍率は２５０％であり、延伸温度を１３７～１３９℃とした。
　得られた位相差フィルムのＲｅ（５５０）は１３７～１４７ｎｍであり、Ｒｅ（４５０）／Ｒｅ（５５０）は０．８９であり、Ｎｚ係数は１．２１であり、配向角（遅相軸の方向）は長尺方向に対し９０°であった。この位相差フィルムを位相差層１として用いた。 2. Production of Retardation Film Using a tenter stretching machine, the obtained polycarbonate resin film was horizontally stretched to obtain a retardation film having a thickness of 50 μm. At that time, the draw ratio was 250%, and the draw temperature was 137 to 139 ° C.
Re (550) of the obtained retardation film is 137 to 147 nm, Re (450) / Re (550) is 0.89, Nz coefficient is 1.21, orientation angle (slow axis) Direction) was 90 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 1.
［参考例７：位相差層を構成する位相差フィルムの作製］
　厚み１４０μｍのポリカーボネート樹脂フィルムを作製したこと以外は参考例６と同様にして、厚み５５μｍの位相差フィルムを得た。得られた位相差フィルムのＲｅ（５５０）は１４７ｎｍであり、Ｒｅ（４５０）／Ｒｅ（５５０）は０．８９であり、Ｎｚ係数は１．２１であり、配向角（遅相軸の方向）は長尺方向に対し９０°であった。この位相差フィルムを位相差層２として用いた。 [Reference Example 7: Production of retardation film constituting retardation layer]
A retardation film having a thickness of 55 μm was obtained in the same manner as in Reference Example 6 except that a polycarbonate resin film having a thickness of 140 μm was produced. Re (550) of the obtained retardation film is 147 nm, Re (450) / Re (550) is 0.89, Nz coefficient is 1.21, orientation angle (direction of slow axis) Was 90 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 2.
［参考例８：位相差層を構成する位相差フィルムの作製］
１．ポリカーボネート樹脂フィルムの作製
　ビス［９－（２－フェノキシカルボニルエチル）フルオレン－９－イル］メタン３８．０６重量部（０．０５９ｍｏｌ）と、イソソルビド（ロケットフルーレ社製、商品名「ＰＯＬＹＳＯＲＢ」）５３．７３重量部（０．３６８ｍｏｌ）と、１，４－シクロヘキサンジメタノール（シス、トランス混合物、ＳＫケミカル社製）９．６４重量部（０．０６７ｍｏｌ）と、ジフェニルカーボネート（三菱化学社製）８１．２８重量部（０．３７９ｍｏｌ）と、触媒としての酢酸カルシウム１水和物３．８３×１０－４重量部（２．１７×１０－６ｍｏｌ）とを反応容器に投入し、反応装置内を減圧窒素置換した。窒素雰囲気下、１５０℃で約１０分間、攪拌しながら原料を溶解させた。反応１段目の工程として２２０℃まで３０分かけて昇温し、６０分間常圧にて反応した。次いで圧力を常圧から１３．３ｋＰａまで９０分かけて減圧し、１３．３ｋＰａで３０分間保持し発生するフェノールを反応系外へ抜き出した。次いで反応２段目の工程として熱媒温度を１５分かけて２４０℃まで昇温しながら、圧力を０．１０ｋＰａ以下まで１５分かけて減圧し、発生するフェノールを反応系外へ抜き出した。所定の撹拌トルクに到達後、窒素で常圧まで復圧して反応を停止し、生成したポリエステルカーボネートを水中に押し出し、ストランドをカッティングしてポリカーボネート樹脂ペレットを得た。
２．位相差フィルムの作製
　上記ポリカーボネート樹脂ペレットから構成されるフィルムを斜め延伸して、厚み５８μｍの位相差フィルムを得た。その際、延伸方向はフィルムの長手方向に対して４５°とした。また、位相差フィルムがλ／４の位相差を発現するよう、延伸倍率は、２～３倍に調整した。また、延伸温度は、１４８℃（すなわち、未延伸変性ポリカーボネートフィルムのＴｇ＋５℃）とした。得られた位相差フィルムのＲｅ（５５０）は１４１ｎｍであり、Ｒｅ（４５０）／Ｒｅ（５５０）は０．８３であり、Ｎｚ係数は１．１であり、光弾性係数は１６×１０－１２Ｐａであり、配向角（遅相軸の方向）は長尺方向に対し４５°であった。この位相差フィルムを位相差層３として用いた。 [Reference Example 8: Production of retardation film constituting retardation layer]
1. Preparation of polycarbonate resin film 38.06 parts by weight (0.059 mol) of bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane and isosorbide (trade name “POLYSORB”, manufactured by Rocket-Fleure) 73 parts by weight (0.368 mol), 1,4-cyclohexanedimethanol (cis, trans mixture, SK Chemical Co., Ltd.) 9.64 parts by weight (0.067 mol), diphenyl carbonate (Mitsubishi Chemical Co., Ltd.) 81. 28 parts by weight (0.379 mol) and calcium acetate monohydrate 3.83 × 10 −4 parts by weight (2.17 × 10 −6 mol) as a catalyst were put into a reaction vessel, The vacuum was replaced with nitrogen. In a nitrogen atmosphere, the raw materials were dissolved while stirring at 150 ° C. for about 10 minutes. As the first step of the reaction, the temperature was raised to 220 ° C. over 30 minutes, and the reaction was performed at normal pressure for 60 minutes. Next, the pressure was reduced from normal pressure to 13.3 kPa over 90 minutes, held at 13.3 kPa for 30 minutes, and the generated phenol was extracted out of the reaction system. Next, as the second step of the reaction, the temperature of the heating medium was raised to 240 ° C. over 15 minutes, the pressure was reduced to 0.10 kPa or less over 15 minutes, and the generated phenol was extracted out of the reaction system. After reaching a predetermined stirring torque, the reaction was stopped by restoring the pressure to normal pressure with nitrogen, the produced polyester carbonate was extruded into water, and the strand was cut to obtain polycarbonate resin pellets.
2. Production of Retardation Film A film composed of the polycarbonate resin pellets was obliquely stretched to obtain a retardation film having a thickness of 58 μm. At that time, the stretching direction was 45 ° with respect to the longitudinal direction of the film. Further, the draw ratio was adjusted to 2 to 3 times so that the retardation film exhibited a retardation of λ / 4. The stretching temperature was 148 ° C. (that is, Tg + 5 ° C. of unstretched modified polycarbonate film). Re (550) of the obtained retardation film is 141 nm, Re (450) / Re (550) is 0.83, Nz coefficient is 1.1, and photoelastic coefficient is 16 × 10 −12. The orientation angle (the direction of the slow axis) was 45 ° with respect to the longitudinal direction. This retardation film was used as the retardation layer 3.
［実施例１］
　偏光板１の第２の保護層面と位相差層１とを、偏光子の吸収軸と位相差層の遅相軸とのなす角度が４５°となるように、アクリル系粘着剤を介して貼り合わせ、円偏光板１を得た。得られた円偏光板１の位相差層面にアクリル系粘着剤層（厚み１５μｍ）を設け、当該粘着剤層表面にリリースライナーを仮着した。さらに、第１の保護層面に、表面保護フィルムを仮着した。保護フィルムは厚さ３８μｍのＰＥＴフィルムに厚さ１０μｍの粘着剤を塗工したものを用いた。なお、第２の保護層の４０℃、相対湿度９２％における透湿度は１５０ｇ／ｍ２／２４Ｈであった。得られた円偏光板１を上記（４）のカール量の評価に供した。結果を表１に示す。さらに、フレキシブルな有機ＥＬ表示装置（サムスン社製、商品名「Ｇａｌａｘｙ　Ｓ６　Ｅｄｇｅ」）から有機ＥＬセルを取り出した。一方、円偏光板１からリリースライナーを剥離し、粘着剤層を介して当該有機ＥＬセルに円偏光板１を貼り合せた。さらに、有機ＥＬセルに貼り合せた円偏光板から表面保護フィルムを剥離した。円偏光板１を貼り合せた有機ＥＬセルを、２３℃、５５％ＲＨの条件下で７２時間放置した後、目視により反りの有無を観察した。その結果、反りも屈曲も認められなかった。 [Example 1]
The second protective layer surface of the polarizing plate 1 and the retardation layer 1 are bonded via an acrylic pressure-sensitive adhesive so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °. In addition, a circularly polarizing plate 1 was obtained. An acrylic pressure-sensitive adhesive layer (thickness 15 μm) was provided on the phase difference layer surface of the obtained circularly polarizing plate 1, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface. The protective film used was a 38 μm thick PET film coated with a 10 μm thick adhesive. The moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% was 150 g / m 2 / 24H. The obtained circularly polarizing plate 1 was subjected to the curl amount evaluation described in (4) above. The results are shown in Table 1. Furthermore, the organic EL cell was taken out from a flexible organic EL display device (product name “Galaxy S6 Edge” manufactured by Samsung). On the other hand, the release liner was peeled from the circularly polarizing plate 1, and the circularly polarizing plate 1 was bonded to the organic EL cell via an adhesive layer. Furthermore, the surface protective film was peeled from the circularly polarizing plate bonded to the organic EL cell. The organic EL cell on which the circularly polarizing plate 1 was bonded was allowed to stand for 72 hours at 23 ° C. and 55% RH, and then visually observed for warpage. As a result, neither warping nor bending was observed.
［実施例２］
　偏光板２の偏光子面と位相差層２とを、偏光子の吸収軸と位相差層の遅相軸とのなす角度が４５°となるように、ＰＶＡ系接着剤を介して貼り合わせ、円偏光板２を得た。得られた円偏光板２の位相差層面にアクリル系粘着剤層（厚み１５μｍ）を設け、当該粘着剤層表面にリリースライナーを仮着した。さらに、第１の保護層面に、表面保護フィルムを仮着した。なお、位相差層の４０℃、相対湿度９２％における透湿度は７０ｇ／ｍ２／２４Ｈであった。得られた円偏光板２を上記（４）のカール量の評価に供した。結果を表１に示す。さらに、得られた円偏光板２を実施例１と同様にして有機ＥＬセルに貼り合せ、実施例１と同様の評価に供した。その結果、反りも屈曲も認められなかった。 [Example 2]
The polarizer surface of the polarizing plate 2 and the retardation layer 2 are bonded through a PVA adhesive so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °. A circularly polarizing plate 2 was obtained. An acrylic pressure-sensitive adhesive layer (thickness 15 μm) was provided on the phase difference layer surface of the obtained circularly polarizing plate 2, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface. The water permeability of the retardation layer at 40 ° C. and a relative humidity of 92% was 70 g / m 2 / 24H. The obtained circularly polarizing plate 2 was subjected to the curl amount evaluation of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 2 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, neither warping nor bending was observed.
［実施例３］
　偏光板５の偏光子面と位相差層３とを、偏光子の吸収軸と位相差層の遅相軸とのなす角度が４５°となるように、ＰＶＡ系接着剤を介して貼り合わせ、円偏光板５を得た。得られた円偏光板５の位相差層面にアクリル系粘着剤層（厚み２０μｍ）を設け、当該粘着剤層表面にリリースライナーを仮着した。さらに、第１の保護層面に、表面保護フィルムを仮着した。なお、位相差層の４０℃、相対湿度９２％における透湿度は８０ｇ／ｍ２／２４Ｈであった。得られた円偏光板５を上記（４）のカール量の評価に供した。結果を表１に示す。さらに、得られた円偏光板５を実施例１と同様にして有機ＥＬセルに貼り合せ、実施例１と同様の評価に供した。その結果、反りも屈曲も認められなかった。 [Example 3]
The polarizer surface of the polarizing plate 5 and the retardation layer 3 are bonded together via a PVA adhesive so that the angle between the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °. A circularly polarizing plate 5 was obtained. An acrylic pressure-sensitive adhesive layer (thickness 20 μm) was provided on the phase difference layer surface of the obtained circularly polarizing plate 5, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface. The water vapor permeability of the retardation layer at 40 ° C. and a relative humidity of 92% was 80 g / m 2 / 24H. The obtained circularly polarizing plate 5 was subjected to the evaluation of the curl amount of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 5 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, neither warping nor bending was observed.
［比較例１］
　偏光板３の偏光子面と位相差層１とを、偏光子の吸収軸と位相差層の遅相軸とのなす角度が４５°となるように、アクリル系粘着剤を介して貼り合わせ、円偏光板３を得た。得られた円偏光板３の位相差層面にアクリル系粘着剤層（厚み１５μｍ）を設け、当該粘着剤層表面にリリースライナーを仮着した。さらに、第１の保護層面に、表面保護フィルムを仮着した。なお、第２の保護層の４０℃、相対湿度９２％における透湿度は１０００ｇ／ｍ２／２４Ｈであった。得られた円偏光板３を上記（４）のカール量の評価に供した。結果を表１に示す。さらに、得られた円偏光板３を実施例１と同様にして有機ＥＬセルに貼り合せ、実施例１と同様の評価に供した。その結果、反りが認められた。 [Comparative Example 1]
The polarizer surface of the polarizing plate 3 and the retardation layer 1 are bonded together via an acrylic pressure-sensitive adhesive so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °. A circularly polarizing plate 3 was obtained. An acrylic pressure-sensitive adhesive layer (thickness 15 μm) was provided on the phase difference layer surface of the obtained circularly polarizing plate 3, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface. The moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% was 1000 g / m 2 / 24H. The obtained circularly polarizing plate 3 was subjected to the curl amount evaluation of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 3 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, warpage was recognized.
［比較例２］
　偏光板４の偏光子面と位相差層１とを、偏光子の吸収軸と位相差層の遅相軸とのなす角度が４５°となるように、アクリル系粘着剤を介して貼り合わせ、円偏光板４を得た。得られた円偏光板４の位相差層面にアクリル系粘着剤層（厚み１５μｍ）を設け、当該粘着剤層表面にリリースライナーを仮着した。さらに、第１の保護層面に、表面保護フィルムを仮着した。なお、第２の保護層の４０℃、相対湿度９２％における透湿度は１５００ｇ／ｍ２／２４Ｈであった。得られた円偏光板４を上記（４）のカール量の評価に供した。結果を表１に示す。さらに、得られた円偏光板４を実施例１と同様にして有機ＥＬセルに貼り合せ、実施例１と同様の評価に供した。その結果、反りが認められた。 [Comparative Example 2]
The polarizer surface of the polarizing plate 4 and the retardation layer 1 are bonded together via an acrylic pressure-sensitive adhesive so that the angle between the absorption axis of the polarizer and the slow axis of the retardation layer is 45 °. A circularly polarizing plate 4 was obtained. An acrylic pressure-sensitive adhesive layer (thickness 15 μm) was provided on the phase difference layer surface of the obtained circularly polarizing plate 4, and a release liner was temporarily attached to the surface of the pressure-sensitive adhesive layer. Furthermore, a surface protective film was temporarily attached to the first protective layer surface. The moisture permeability of the second protective layer at 40 ° C. and a relative humidity of 92% was 1500 g / m 2 / 24H. The obtained circularly polarizing plate 4 was subjected to the evaluation of the curl amount of (4) above. The results are shown in Table 1. Further, the obtained circularly polarizing plate 4 was bonded to an organic EL cell in the same manner as in Example 1, and subjected to the same evaluation as in Example 1. As a result, warpage was recognized.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
＜評価＞
　表１から明らかなように、本発明の実施例の円偏光板は、リリースライナーおよび表面保護フィルムを剥離した状態での経時変化によるカール量が小さいことがわかる。結果として、フレキシブルな画像表示装置に適用した場合に、画像表示装置自体の屈曲や反りを良好に抑制できることが確認された。 <Evaluation>
As is clear from Table 1, it can be seen that the circularly polarizing plate of the example of the present invention has a small amount of curl due to a change with time in a state where the release liner and the surface protective film are peeled off. As a result, when applied to a flexible image display device, it was confirmed that bending and warping of the image display device itself can be satisfactorily suppressed.
　本発明の円偏光板は、フレキシブルな画像表示装置（例えば、有機ＥＬ表示装置）に好適に用いられる。 The circularly polarizing plate of the present invention is suitably used for a flexible image display device (for example, an organic EL display device).
　１１　　　第１の保護層
　１２　　　第２の保護層
　２０　　　偏光子
　３０　　　位相差層
　４０　　　ハードコート層
　５０　　　粘着剤層
　７０　　　表面保護フィルム
１００　　　円偏光板 DESCRIPTION OF SYMBOLS 11 1st protective layer 12 2nd protective layer 20 Polarizer 30 Phase difference layer 40 Hard-coat layer 50 Adhesive layer 70 Surface protective film 100 Circularly-polarizing plate

Claims (8)

  1. 　第１の保護層と、偏光子と、第２の保護層と、面内位相差Ｒｅ（５５０）が８０ｎｍ～２００ｎｍである位相差層と、をこの順に有し、
    　該第２の保護層の４０℃、相対湿度９２％における透湿度が１６０ｇ／ｍ２／２４Ｈ未満であり、
    　フレキシブルな画像表示装置に用いられる、
    　円偏光板。     A first protective layer, a polarizer, a second protective layer, and a retardation layer having an in-plane retardation Re (550) of 80 nm to 200 nm in this order;
    The moisture permeability at 40 ° C. and a relative humidity of 92% of the second protective layer is less than 160 g / m 2 / 24H,
    Used in flexible image display devices,
    Circular polarizing plate.
  2. 　前記第２の保護層が省略されて前記位相差層が前記偏光子の保護層を兼ね、該位相差層の４０℃、相対湿度９２％における透湿度が１６０ｇ／ｍ２／２４Ｈ未満である、請求項１に記載の円偏光板。 The second protective layer is omitted and the retardation layer also serves as a protective layer of the polarizer, and the moisture permeability of the retardation layer at 40 ° C. and a relative humidity of 92% is less than 160 g / m 2 / 24H. The circularly-polarizing plate of Claim 1.
  3. 　前記偏光子の吸収軸と前記位相差層の遅相軸とのなす角度θが３５°～５５°である、請求項１または２に記載の円偏光板。 3. The circularly polarizing plate according to claim 1, wherein an angle θ formed by an absorption axis of the polarizer and a slow axis of the retardation layer is 35 ° to 55 °.
  4. 　前記第１の保護層の外側にハードコート層をさらに有する、請求項１から３のいずれかに記載の円偏光板。 The circularly polarizing plate according to any one of claims 1 to 3, further comprising a hard coat layer outside the first protective layer.
  5. 　前記位相差層側の最外部に粘着剤層をさらに有し、該粘着剤層表面にリリースライナーが仮着されている、請求項１から４のいずれかに記載の円偏光板。 The circularly polarizing plate according to any one of claims 1 to 4, further comprising an adhesive layer on the outermost side of the retardation layer side, and a release liner being temporarily attached to the surface of the adhesive layer.
  6. 　前記第１の保護層側の最外部に表面保護フィルムが仮着されている、請求項１から５のいずれかに記載の円偏光板。 The circularly polarizing plate according to any one of claims 1 to 5, wherein a surface protective film is temporarily attached to the outermost part on the first protective layer side.
  7. 　前記リリースライナーおよび前記表面保護フィルムが仮着された状態；該リリースライナーが剥離除去され、該表面保護フィルムが仮着された状態；ならびに、該リリースライナーおよび該表面保護フィルムが剥離除去された状態のそれぞれの状態において、２５℃±５℃、相対湿度５５％±１０％の環境下に７２時間置いた場合のカール量が±６ｍｍ以内である、請求項５または６に記載の円偏光板。 The release liner and the surface protective film are temporarily attached; the release liner is peeled off and the surface protective film is temporarily attached; and the release liner and the surface protective film are peeled and removed. 7. The circularly polarizing plate according to claim 5, wherein the curl amount is within ± 6 mm when placed in an environment of 25 ° C. ± 5 ° C. and a relative humidity of 55% ± 10% for 72 hours.
  8. 　請求項１から７のいずれかに記載の円偏光板を備える、フレキシブルな画像表示装置。
          A flexible image display device comprising the circularly polarizing plate according to claim 1.
PCT/JP2016/085470 2015-12-10 2016-11-30 Circular polarizing plate and flexible image display device using same WO2017098970A1 (en)

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CN201680071187.1A CN108292005A (en) 2015-12-10 2016-11-30 Circular polarizing disk and the flexible image display device for having used it

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