WO2020080186A1 - Plaque de polarisation avec couche de retard et dispositif d'affichage d'image l'utilisant - Google Patents

Plaque de polarisation avec couche de retard et dispositif d'affichage d'image l'utilisant Download PDF

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Publication number
WO2020080186A1
WO2020080186A1 PCT/JP2019/039638 JP2019039638W WO2020080186A1 WO 2020080186 A1 WO2020080186 A1 WO 2020080186A1 JP 2019039638 W JP2019039638 W JP 2019039638W WO 2020080186 A1 WO2020080186 A1 WO 2020080186A1
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Prior art keywords
retardation layer
polarizing plate
film
layer
retardation
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PCT/JP2019/039638
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English (en)
Japanese (ja)
Inventor
後藤　周作
寛教 柳沼
寛 友久
清水　享
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日東電工株式会社
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Priority claimed from JP2019183681A external-priority patent/JP7355586B2/ja
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Priority to CN201980067856.1A priority Critical patent/CN112840247B/zh
Priority to KR1020217008931A priority patent/KR20210071965A/ko
Publication of WO2020080186A1 publication Critical patent/WO2020080186A1/fr

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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
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • 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
    • 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
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/14—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of the electroluminescent material, or by the simultaneous addition of the electroluminescent material in or onto the light source
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • 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

Definitions

  • the present invention relates to a polarizing plate with a retardation layer and an image display device using the same.
  • image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices for example, organic EL display devices and inorganic EL display devices
  • EL electroluminescence
  • a polarizing plate and a retardation plate are typically used for the image display device.
  • a polarizing plate with a retardation layer in which a polarizing plate and a retardation plate are integrated is widely used (for example, Patent Document 1), and recently, there is a strong demand for thinner image display devices. Accordingly, there is an increasing demand for thinner polarizing plates with retardation layers.
  • the present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a polarizing plate with a retardation layer, which is thin, excellent in handleability, and excellent in optical characteristics. .
  • the polarizing plate with a retardation layer of the present invention has a polarizing plate including a polarizing film, a protective layer on at least one side of the polarizing film, and a retardation layer.
  • the polarizing film is composed of a polyvinyl alcohol-based resin film containing a dichroic material, has a thickness of 8 ⁇ m or less, a single transmittance of 45% or more, and a polarization degree of 97% or more.
  • Re (550) of the retardation layer is 100 nm to 190 nm, Re (450) / Re (550) is 0.8 or more and less than 1, and the slow axis of the retardation layer and the absorption axis of the polarizing film.
  • the protective layer is composed of a base material having an elastic modulus of 3000 MPa or more.
  • the polarizing plate with a retardation layer has a total thickness of 90 ⁇ m or less, a front reflection hue of 3.5 or less, and the protective layer is made of a resin film having an elastic modulus of 3000 MPa or more. Composed.
  • the protective layer is composed of a triacetyl cellulose resin film.
  • the polarizing plate includes the polarizing film and the protective layer arranged only on one side of the polarizing film, and the retardation layer includes the polarizing film via an adhesive layer. Are pasted together.
  • the above-mentioned retardation layer comprises a polycarbonate resin film.
  • the retardation layer is composed of a polycarbonate resin film having a thickness of 40 ⁇ m or less.
  • the difference between the maximum value and the minimum value of the single-piece transmittance in the area of 50 cm 2 of the polarizing film is 0.2% or less.
  • the polarizing plate with a retardation layer has a width of 1000 mm or more, and the difference between the maximum value and the minimum value of the single transmittance at a position along the width direction of the polarizing film is 0.5%. It is the following.
  • the single transmittance of the polarizing film is 46% or less and the polarization degree is 99% or less.
  • the above-mentioned polarizing plate with a retardation layer further has a conductive layer or an isotropic substrate with a conductive layer outside the above-mentioned retardation layer.
  • the polarizing plate with a retardation layer is elongated, the polarizing film has an absorption axis in the longitudinal direction, and the retardation layer is 40 ° to 40 ° with respect to the longitudinal direction.
  • an image display device is provided.
  • This image display device includes the above polarizing plate with a retardation layer.
  • the image display device is an organic electroluminescence display device or an inorganic electroluminescence display device.
  • a halide typically potassium iodide
  • PVA polyvinyl alcohol
  • two-stage stretching including auxiliary stretching in air and stretching in water, and drying and shrinking with a heating roll.
  • FIG. 1 is a schematic sectional view of a polarizing plate with a retardation layer according to one embodiment of the present invention.
  • FIG. 6 is a schematic cross-sectional view of a polarizing plate with a retardation layer according to another embodiment of the present invention. It is a schematic diagram showing an example of dry shrinkage processing using a heating roll in a manufacturing method of a polarizing film used for a polarizing plate with a phase contrast layer of the present invention.
  • Refractive index (nx, ny, nz) “Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), and “ny” is the direction in the plane that is orthogonal to the slow axis (that is, 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.
  • Phase difference in the thickness direction (Rth) is a phase difference in the thickness direction measured with light having a wavelength of ⁇ nm at 23 ° C.
  • Rth (550) is a phase difference in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C.
  • FIG. 1 is a schematic sectional view of a polarizing plate with a retardation layer according to an embodiment of the present invention.
  • the polarizing plate 100 with a retardation layer of this embodiment includes a polarizing plate 10 and a retardation layer 20.
  • the polarizing plate 10 includes a polarizing film 11, a first protective layer 12 arranged on one side of the polarizing film 11, and a second protective layer 13 arranged on the other side of the polarizing film 11. .
  • one of the first protective layer 12 and the second protective layer 13 may be omitted.
  • the retardation layer 20 can also function as a protective layer for the polarizing film 11
  • the second protective layer 13 may be omitted.
  • the polarizing film is composed of a polyvinyl alcohol-based resin film containing a dichroic substance.
  • the polarizing film has a thickness of 8 ⁇ m or less, a single transmittance of 45% or more, and a polarization degree of 97% or more.
  • a retardation layer-attached polarizing plate 101 may be provided with another retardation layer 50 and / or a conductive layer or an isotropic substrate 60 with a conductive layer.
  • Another retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically provided outside the retardation layer 20 (on the side opposite to the polarizing plate 10).
  • Another retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically provided in this order from the retardation layer 20 side.
  • the different retardation layer 50 and the conductive layer or the isotropic substrate 60 with a conductive layer are typically arbitrary layers provided as needed, and either one or both may be omitted.
  • the retardation layer 20 may be referred to as a first retardation layer
  • another retardation layer 50 may be referred to as a second retardation layer.
  • the polarizing plate with a retardation layer is a so-called inner layer in which a touch sensor is incorporated between an image display cell (for example, an organic EL cell) and the polarizing plate. It can be applied to a touch panel type input display device.
  • Re (550) of the first retardation layer 20 is 100 nm to 190 nm, and Re (450) / Re (550) is 0.8 or more and less than 1. Further, the angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizing film 11 is 40 ° to 50 °.
  • the above-described embodiments may be combined as appropriate, and the components in the above-described embodiments may be modified as is obvious in the art.
  • the configuration in which the isotropic substrate 60 with a conductive layer is provided outside the second retardation layer 50 is replaced with an optically equivalent configuration (for example, a laminate of the second retardation layer and the conductive layer). Good.
  • the polarizing plate with a retardation layer according to the embodiment of the present invention may further include another retardation layer.
  • Other optical properties of the retardation layer for example, refractive index properties, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position and the like can be appropriately set according to the purpose.
  • the polarizing plate with a retardation layer of the present invention may have a sheet-like shape or a long shape.
  • "long shape” means an elongated shape having a length sufficiently longer than the width, and for example, an elongated shape having a length 10 times or more, preferably 20 times or more the width. Including.
  • the long polarizing plate with a retardation layer can be wound into a roll.
  • the polarizing plate and the retardation layer are also elongated.
  • the polarizing film preferably has an absorption axis in the longitudinal direction.
  • the first retardation layer is preferably an obliquely stretched film having a slow axis in a direction forming an angle of 40 ° to 50 ° with respect to the lengthwise direction. If the polarizing film and the first retardation layer have such a configuration, the polarizing plate with the retardation layer can be produced by roll-to-roll.
  • an adhesive layer (not shown) is provided on the opposite side of the retardation layer to the polarizing plate, and the polarizing plate with retardation layer can be attached to the image display cell. Further, it is preferable that a release film is temporarily attached to the surface of the pressure-sensitive adhesive layer until the polarizing plate with a retardation layer is used. By temporarily attaching the release film, the pressure-sensitive adhesive layer can be protected and the roll can be formed.
  • the front reflection hue ( ⁇ (a * 2 + b * 2 )) of the polarizing plate with a retardation layer is preferably 3.5 or less, more preferably 3.0 or less.
  • the front reflection hue is within the above range, undesired coloring is suppressed, and as a result, a polarizing plate with a retardation layer having excellent reflection characteristics can be obtained.
  • the total thickness of the polarizing plate with a retardation layer is preferably 140 ⁇ m or less, more preferably 120 ⁇ m or less, even more preferably 100 ⁇ m or less, even more preferably 90 ⁇ m or less, still more preferably 85 ⁇ m or less. is there.
  • the lower limit of the total thickness can be, for example, 30 ⁇ m.
  • an extremely thin polarizing plate with a retardation layer can be realized in this way.
  • Such a polarizing plate with a retardation layer can have extremely excellent flexibility and bending durability.
  • Such a polarizing plate with a retardation layer can be particularly suitably applied to a curved image display device and / or a bendable or bendable image display device.
  • the total thickness of the polarizing plate with a retardation layer constitutes the polarizing plate with a retardation layer except for an adhesive layer for adhering the polarizing plate with a retardation layer to an external adherend such as a panel or glass. It means the total thickness of all layers (that is, the total thickness of the polarizing plate with a retardation layer is a pressure-sensitive adhesive layer for sticking the polarizing plate with a retardation layer to an adjacent member such as an image display cell and its surface. Does not include the thickness of the release film that can be applied).
  • the polarizing film 11 has a thickness of 8 ⁇ m or less, a single transmittance of 45% or more, and a polarization degree of 97% or more.
  • the single-body transmittance and the polarization degree are in a trade-off relationship with each other, and increasing the single-body transmittance may decrease the polarization degree, and increasing the polarization degree may decrease the single-body transmittance. Therefore, conventionally, it has been difficult to practically use a thin polarizing film that satisfies the optical characteristics of a single transmittance of 45% or more and a polarization degree of 97% or more. It is a characteristic of the present invention to use a thin polarizing film having excellent optical characteristics such that the single-piece transmittance is 45% or more and the polarization degree is 97% or more, and variation in the optical characteristics is suppressed. There is one.
  • the thickness of the polarizing film is preferably 1 ⁇ m to 8 ⁇ m, more preferably 1 ⁇ m to 7 ⁇ m, and further preferably 2 ⁇ m to 5 ⁇ m.
  • the polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm.
  • the single transmittance of the polarizing film is preferably 46% or less.
  • the polarization degree of the polarizing film is preferably 97.5% or more, more preferably 98% or more. On the other hand, the polarization degree is preferably 99% or less.
  • the single-piece transmittance is typically a Y value measured using an ultraviolet-visible spectrophotometer and subjected to luminosity correction.
  • the polarization degree is typically obtained by the following formula based on the parallel transmittance Tp and the orthogonal transmittance Tc measured by using an ultraviolet-visible spectrophotometer and subjected to the visibility correction.
  • Polarization degree (%) ⁇ (Tp-Tc) / (Tp + Tc) ⁇ 1/2 ⁇ 100
  • the transmittance of a thin polarizing film having a thickness of 8 ⁇ m or less is typically obtained by laminating a polarizing film (refractive index of surface: 1.53) and a protective film (refractive index: 1.50). It is measured using an ultraviolet-visible spectrophotometer with the body as the measurement target.
  • a polarizing film reffractive index of surface: 1.53
  • a protective film reffractive index: 1.50
  • the reflectance at the interface of each layer may change, and as a result, the measured transmittance may change.
  • the measured value of the transmittance may be corrected according to the refractive index of the surface of the protective film in contact with the air interface.
  • the transmittance correction value C is expressed by the following equation using the reflectance R 1 (transmission axis reflectance) of polarized light parallel to the transmission axis at the interface between the protective film and the air layer.
  • R 0 ((1.50-1) 2 /(1.50+1) 2) ⁇ (T 1/100)
  • R 1 ((n 1 -1 ) 2 / (n 1 +1) 2) ⁇ (T 1/100)
  • R 0 is the transmission axis reflectance when a protective film having a refractive index of 1.50 is used
  • n 1 is the refractive index of the protective film used
  • T 1 is the transmittance of the polarizing film. Is.
  • the correction amount C is about 0.2%.
  • the change amount of the correction value C when the transmittance T 1 of the polarizing film is changed by 2% is 0.03% or less, and the transmittance of the polarizing film is the correction value C.
  • the effect on the value of is limited.
  • the protective film has absorption other than surface reflection, appropriate correction can be performed according to the amount of absorption.
  • the polarizing plate with a retardation layer has a width of 1000 mm or more, and therefore the polarizing film also has a width of 1000 mm or more.
  • the difference (D1) between the maximum value and the minimum value of the single transmittance at the position along the width direction of the polarizing film is preferably 0.5% or less, more preferably 0.4% or less. , And more preferably 0.3% or less.
  • D1 is within the above range, a polarizing plate with a retardation layer having excellent optical characteristics can be industrially produced.
  • the difference (D2) between the maximum value and the minimum value of the single transmittance in the region of 50 cm 2 is preferably 0.2% or less, more preferably 0.15%. It is below, and more preferably 0.1% or below.
  • D2 is within the above range, it is possible to suppress variations in luminance on the display screen when the polarizing plate with a retardation layer is used in an image display device.
  • the polarizing film can be typically manufactured by using a laminate of two or more layers.
  • a specific example of the polarizing film obtained by using the laminated body is a polarizing film obtained by using a laminated body of a resin base material and a PVA-based resin layer formed by coating on the resin base material.
  • a polarizing film obtained by using a laminate of a resin base material and a PVA-based resin layer applied and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying it.
  • a PVA-based resin layer is formed thereon to obtain a laminate of a resin substrate and a PVA-based resin layer; the laminate is stretched and dyed to form the PVA-based resin layer as a polarizing film. obtain.
  • the stretching typically includes dipping the laminate in a boric acid aqueous solution and stretching. Further, the stretching may further include optionally stretching the laminate in air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution.
  • the obtained resin base material / polarizing film laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizing film), or the resin base material is peeled from the resin base material / polarizing film laminate.
  • any appropriate protective layer may be laminated and used on the peeled surface depending on the purpose. Details of the method for producing such a polarizing film are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. The entire description of the publication is incorporated herein by reference.
  • the method for manufacturing a polarizing film is typically a laminate of a polyvinyl alcohol resin layer containing a halide and a polyvinyl alcohol resin on one side of a long thermoplastic resin substrate. And subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment of shrinking 2% or more in the width direction by heating while conveying in the longitudinal direction in this order. including.
  • a polarizing film having a thickness of 8 ⁇ m or less, a single transmittance of 45% or more, and a polarization degree of 97% or more, which has excellent optical characteristics and in which variations in optical characteristics are suppressed, can be provided. .
  • the crystallinity of PVA can be increased and high optical characteristics can be achieved even when PVA is applied onto the thermoplastic resin.
  • by preliminarily enhancing the orientation of PVA it is possible to prevent problems such as reduction in orientation and dissolution of PVA when immersed in water in the subsequent dyeing step or stretching step, and high optical characteristics. Can be achieved.
  • the PVA-based resin layer is dipped in a liquid, the disorder of the alignment of the polyvinyl alcohol molecules and the deterioration of the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide.
  • optical characteristics of the polarizing film obtained through a treatment process such as a dyeing treatment and an underwater stretching treatment performed by immersing the laminate in a liquid can improve the optical characteristics of the polarizing film obtained through a treatment process such as a dyeing treatment and an underwater stretching treatment performed by immersing the laminate in a liquid. Further, the optical characteristics can be improved by shrinking the laminate in the width direction by the dry shrinking treatment.
  • the first protective layer 12 and the second protective layer 13 are each formed of any suitable film that can be used as a protective layer of a polarizing film.
  • the material serving as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyether sulfone resins, and polysulfone resins.
  • TAC triacetyl cellulose
  • polyester resins polyvinyl alcohol resins
  • polycarbonate resins polyamide resins
  • polyimide resins polyether sulfone resins
  • polysulfone resins polysulfone resins.
  • thermosetting resin such as a (meth) acrylic resin, a urethane resin, a (meth) acrylic urethane resin, an epoxy resin, a silicone resin, or an ultraviolet curable resin
  • a glassy polymer such as a siloxane polymer may be used.
  • the polymer film described in JP 2001-343529 A (WO 01/37007) can also be used. Examples of the material of this film include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain.
  • the polymer film can be, for example, an extruded product of the resin composition.
  • the protective layer (particularly, the protective layer on the viewing side) includes a TAC resin. By using the TAC resin film as the protective layer, the bending durability can be improved.
  • the polarizing plate with a retardation layer of the present invention is typically arranged on the viewing side of the image display device as described later, and the first protective layer 12 is typically arranged on the viewing side. Therefore, the first protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, sticking prevention treatment, and antiglare treatment, if necessary. Further / or, if necessary, the first protective layer 12 is processed to improve the visibility when viewed through polarized sunglasses (typically, a (elliptical) circular polarization function is added, (Giving an ultrahigh phase difference) may be applied. By performing such a process, excellent visibility can be realized even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the polarizing plate with a retardation layer can be suitably applied to an image display device that can be used outdoors.
  • polarized sunglasses typically, a (elliptical) circular polarization function is added, (Giving an ultrahigh phase difference
  • the thickness of the first protective layer is preferably 5 ⁇ m to 80 ⁇ m, more preferably 10 ⁇ m to 40 ⁇ m, still more preferably 10 ⁇ m to 35 ⁇ m.
  • the thickness of the outer protective layer is the thickness including the thickness of the surface treated layer.
  • the second protective layer 13 is preferably optically isotropic in one embodiment.
  • “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 second protective layer 13 may be a retardation layer having any appropriate retardation value in one embodiment.
  • the in-plane retardation Re (550) of the retardation layer is, for example, 110 nm to 150 nm.
  • the thickness of the second protective layer is preferably 5 ⁇ m to 80 ⁇ m, more preferably 10 ⁇ m to 40 ⁇ m, still more preferably 10 ⁇ m to 30 ⁇ m. From the viewpoint of reduction in thickness and weight, the second protective layer can be preferably omitted.
  • the polarizing film is, for example, a polyvinyl alcohol resin layer (PVA resin layer) containing a halide and a polyvinyl alcohol resin (PVA resin) on one side of a long thermoplastic resin substrate.
  • PVA resin layer polyvinyl alcohol resin layer
  • PVA resin polyvinyl alcohol resin layer
  • the content of the halide in the PVA-based resin layer is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin.
  • the drying shrinkage treatment is preferably performed using a heating roll, and the temperature of the heating roll is preferably 60 ° C. to 120 ° C.
  • the shrinkage ratio in the width direction of the laminate by the dry shrinkage treatment is preferably 2% or more.
  • the polarizing film described in the above section B-1 can be obtained.
  • a laminate including a PVA-based resin layer containing a halide is prepared, and the laminate is stretched in multiple stages including in-air auxiliary stretching and underwater stretching, and the laminated laminate is heated with a heating roll. It is possible to obtain a polarizing film having excellent optical characteristics (typically, single-body transmittance and polarization degree) and suppressing variations in optical characteristics.
  • the laminate can be uniformly shrunk while being conveyed.
  • a heating roll in the drying shrinkage treatment step the laminate can be uniformly shrunk while being conveyed.
  • the optical characteristics of the obtained polarizing film be improved, but also a polarizing film with excellent optical characteristics can be stably produced, and variations in optical characteristics (particularly, single transmittance) of the polarizing film can be suppressed. can do.
  • thermoplastic resin substrate and the PVA-based resin layer any suitable method can be adopted.
  • a PVA-based resin layer is formed on the thermoplastic resin substrate by applying a coating liquid containing a halide and a PVA-based resin on the surface of the thermoplastic resin substrate and drying the coating liquid.
  • the content of the halide in the PVA-based resin layer is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin.
  • any appropriate method can be adopted as the method for applying the application liquid.
  • a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, a knife coating method (a comma coating method, etc.) and the like can be mentioned.
  • the coating / drying temperature of the coating liquid is preferably 50 ° C. or higher.
  • the thickness of the PVA resin layer is preferably 3 ⁇ m to 40 ⁇ m, more preferably 3 ⁇ m to 20 ⁇ m.
  • the thermoplastic resin substrate Before the PVA-based resin layer is formed, the thermoplastic resin substrate may be subjected to surface treatment (for example, corona treatment), or the easily adhesive layer may be formed on the thermoplastic resin substrate. By performing such a treatment, the adhesion between the thermoplastic resin base material and the PVA-based resin layer can be improved.
  • surface treatment for example, corona treatment
  • the easily adhesive layer may be formed on the thermoplastic resin substrate.
  • Thermoplastic resin substrate The thickness of the thermoplastic resin substrate is preferably 20 ⁇ m to 300 ⁇ m, more preferably 50 ⁇ m to 200 ⁇ m. If it is less than 20 ⁇ m, it may be difficult to form the PVA-based resin layer. If it exceeds 300 ⁇ m, it may take a long time for the thermoplastic resin substrate to absorb water in the below-described underwater stretching treatment, and an excessive load may be required for stretching.
  • the thermoplastic resin base material preferably has a water absorption of 0.2% or more, and more preferably 0.3% or more.
  • the thermoplastic resin base material absorbs water, and the water acts as a plasticizer and can be plasticized. As a result, the stretching stress can be significantly reduced, and stretching can be performed at a high ratio.
  • the water absorption of the thermoplastic resin substrate is preferably 3.0% or less, more preferably 1.0% or less.
  • thermoplastic resin substrate can be adjusted, for example, by introducing a modifying group into the constituent material.
  • the water absorption rate is a value determined according to JIS K7209.
  • the glass transition temperature (Tg) of the thermoplastic resin base material is preferably 120 ° C. or lower.
  • Tg The glass transition temperature of the thermoplastic resin base material.
  • the temperature is preferably 100 ° C. or lower, and more preferably 90 ° C. or lower.
  • the glass transition temperature of the thermoplastic resin substrate is preferably 60 ° C or higher.
  • the PVA-based resin layer can be stretched well at a suitable temperature (for example, about 60 ° C.).
  • the glass transition temperature of the thermoplastic resin substrate can be adjusted, for example, by introducing a modifying group into the constituent material and heating it with a crystallization material.
  • the glass transition temperature (Tg) is a value determined according to JIS K7121.
  • thermoplastic resin can be adopted as the constituent material of the thermoplastic resin base material.
  • the thermoplastic resin include ester-based resins such as polyethylene terephthalate-based resins, cycloolefin-based resins such as norbornene-based resins, olefin-based resins such as polypropylene, polyamide-based resins, polycarbonate-based resins, and copolymer resins thereof. Is mentioned. Among these, norbornene-based resins and amorphous polyethylene terephthalate-based resins are preferable.
  • an amorphous (non-crystallized) polyethylene terephthalate resin is preferably used.
  • an amorphous (hard to crystallize) polyethylene terephthalate resin is particularly preferably used.
  • Specific examples of the amorphous polyethylene terephthalate resin include a copolymer further containing isophthalic acid and / or cyclohexanedicarboxylic acid as a dicarboxylic acid, and a copolymer further containing cyclohexanedimethanol or diethylene glycol as a glycol.
  • the thermoplastic resin base material is composed of a polyethylene terephthalate resin having an isophthalic acid unit.
  • a thermoplastic resin substrate has extremely excellent stretchability and can suppress crystallization during stretching. It is considered that this is because the main chain is largely bent by introducing the isophthalic acid unit.
  • the polyethylene terephthalate resin has a terephthalic acid unit and an ethylene glycol unit.
  • the content ratio of the isophthalic acid unit is preferably 0.1 mol% or more, more preferably 1.0 mol% or more based on the total of all repeating units. This is because a thermoplastic resin substrate having extremely excellent stretchability can be obtained.
  • the content ratio of the isophthalic acid unit is preferably 20 mol% or less, more preferably 10 mol% or less, based on the total of all repeating units.
  • the crystallinity can be favorably increased in the drying shrinkage treatment described below.
  • the thermoplastic resin substrate may be stretched in advance (before forming the PVA-based resin layer).
  • the elongated thermoplastic resin substrate is stretched in the lateral direction.
  • the lateral direction is preferably a direction orthogonal to the stretching direction of the laminate described below.
  • orthogonal includes the case of being substantially orthogonal.
  • substantially orthogonal includes the case of 90 ° ⁇ 5.0 °, preferably 90 ° ⁇ 3.0 °, and more preferably 90 ° ⁇ 1.0 °.
  • the stretching temperature of the thermoplastic resin substrate is preferably Tg-10 ° C to Tg + 50 ° C with respect to the glass transition temperature (Tg).
  • the stretch ratio of the thermoplastic resin substrate is preferably 1.5 to 3.0 times.
  • thermoplastic resin substrate Any appropriate method can be adopted as a method for stretching the thermoplastic resin substrate. Specifically, it may be fixed-end stretching or free-end stretching. The stretching method may be dry or wet. Stretching of the thermoplastic resin substrate may be performed in one stage or in multiple stages. When performing in multiple stages, the above-mentioned draw ratio is a product of the draw ratio of each stage.
  • the coating liquid contains a halide and a PVA-based resin as described above.
  • the coating liquid is typically a solution prepared by dissolving the halide and the PVA resin in a solvent.
  • the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. These can be used alone or in combination of two or more. Of these, water is preferable.
  • the PVA-based resin concentration of the solution is preferably 3 to 20 parts by weight with respect to 100 parts by weight of the solvent. With such a resin concentration, it is possible to form a uniform coating film in close contact with the thermoplastic resin substrate.
  • the content of the halide in the coating liquid is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the PVA-based resin.
  • Additives may be added to the coating liquid.
  • the additive include a plasticizer and a surfactant.
  • the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin.
  • the surfactant include nonionic surfactants. These can be used for the purpose of further improving the uniformity, dyeability and stretchability of the obtained PVA-based resin layer.
  • any suitable resin can be adopted as the PVA-based resin.
  • Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer.
  • Polyvinyl alcohol is obtained by saponifying polyvinyl acetate.
  • the ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer.
  • the degree of saponification of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. .
  • the degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizing film having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.
  • the average degree of polymerization of the PVA resin can be appropriately selected according to the purpose.
  • the average degree of polymerization is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300.
  • the average degree of polymerization can be determined according to JIS K 6726-1994.
  • any suitable halide can be adopted as the above-mentioned halide.
  • examples include iodide and sodium chloride.
  • examples of iodides include potassium iodide, sodium iodide, and lithium iodide. Among these, potassium iodide is preferable.
  • the amount of halide in the coating solution is preferably 5 to 20 parts by weight with respect to 100 parts by weight of PVA-based resin, and more preferably 10 to 15 parts by weight with respect to 100 parts by weight of PVA-based resin. It is a department. If the amount of the halide exceeds 20 parts by weight with respect to 100 parts by weight of the PVA-based resin, the halide may bleed out and the polarizing film finally obtained may become cloudy.
  • the orientation of the polyvinyl alcohol molecules in the PVA-based resin increases, but when the stretched PVA-based resin layer is immersed in a liquid containing water, the polyvinyl alcohol molecules The orientation may be disturbed and the orientation may be deteriorated.
  • the laminate when a laminate of a thermoplastic resin base material and a PVA-based resin layer is stretched in boric acid water, the laminate is heated in boric acid water at a relatively high temperature in order to stabilize the stretching of the thermoplastic resin base material. In the case of stretching, the above-mentioned tendency of decreasing the degree of orientation is remarkable.
  • stretching of a PVA film alone in boric acid water is generally performed at 60 ° C.
  • stretching of a laminate of A-PET (thermoplastic resin base material) and PVA-based resin layer is performed. It is carried out at a high temperature of around 70 ° C.
  • the orientation of PVA in the initial stage of stretching may be lowered in a stage before being raised by the underwater stretching.
  • by forming a laminate of a PVA-based resin layer containing a halide and a thermoplastic resin substrate and stretching the laminate at high temperature in air (auxiliary stretching) before stretching in boric acid water.
  • the crystallization of the PVA-based resin in the PVA-based resin layer of the laminate after the auxiliary stretching can be promoted.
  • the PVA-based resin layer when the PVA-based resin layer is immersed in the liquid, the disorder of the alignment of the polyvinyl alcohol molecules and the deterioration of the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide.
  • This can improve the optical characteristics of the polarizing film obtained through a treatment process such as a dyeing treatment and an underwater stretching treatment performed by immersing the laminate in a liquid.
  • auxiliary stretching treatment In-air auxiliary stretching treatment
  • a two-stage stretching method is selected in which dry stretching (auxiliary stretching) and boric acid in-water stretching are combined.
  • auxiliary stretching like two-stage stretching, it is possible to perform stretching while suppressing crystallization of the thermoplastic resin substrate, and excessive crystallization of the thermoplastic resin substrate in subsequent boric acid underwater stretching. Thereby, the problem that the stretchability is lowered can be solved, and the laminate can be stretched at a higher ratio.
  • the PVA-based resin on the thermoplastic resin base material in order to suppress the influence of the glass transition temperature of the thermoplastic resin base material, compared with the case of applying the PVA-based resin on a normal metal drum.
  • the crystallization of the PVA-based resin becomes relatively low, which may cause a problem that sufficient optical characteristics cannot be obtained.
  • the crystallinity of the PVA-based resin can be increased even when the PVA-based resin is applied on the thermoplastic resin, and high optical characteristics can be achieved.
  • the orientation of the PVA-based resin it is possible to prevent problems such as deterioration of the orientation of the PVA-based resin and dissolution when the PVA-based resin is immersed in water in the subsequent dyeing step or stretching step. It becomes possible to achieve high optical characteristics.
  • the stretching method for the in-air auxiliary stretching may be fixed-end stretching (for example, a stretching method using a tenter stretching machine) or free-end stretching (for example, a uniaxial stretching method in which a laminate is passed between rolls having different peripheral speeds).
  • free end stretching can be positively adopted in order to obtain high optical characteristics.
  • the in-air stretching treatment includes a heating roll stretching step of stretching the laminate by the difference in peripheral speed between the heating rolls while conveying the laminate in the longitudinal direction.
  • the in-air stretching treatment typically includes a zone stretching step and a heating roll stretching step.
  • the order of the zone stretching step and the heating roll stretching step is not limited, and the zone stretching step may be performed first or the heating roll stretching step may be performed first.
  • the zone stretching step may be omitted.
  • the zone stretching step and the heated roll stretching step are performed in this order.
  • stretching is performed by gripping the film end portion and widening the distance between the tenter in the flow direction (expansion of the distance between the tenter is the stretching ratio).
  • the distance of the tenter in the width direction (direction perpendicular to the flow direction) is set to be arbitrarily close.
  • it can be set so as to be closer to the free end stretching with respect to the stretching ratio in the machine direction.
  • shrinkage ratio in the width direction (1 / stretching ratio) 1/2 is calculated.
  • Assisted stretching in the air may be performed in one stage or in multiple stages.
  • the draw ratio is the product of the draw ratios in each stage.
  • the stretching direction in the in-air auxiliary stretching is preferably substantially the same as the stretching direction in the underwater stretching.
  • the draw ratio in the in-air auxiliary drawing is preferably 2.0 to 3.5 times.
  • the maximum draw ratio when the in-air auxiliary drawing and the underwater drawing are combined is preferably 5.0 times or more, more preferably 5.5 times or more, and further preferably 6.0 times, with respect to the original length of the laminate. That is all.
  • the "maximum stretch ratio” means a stretch ratio immediately before the laminated body breaks, and separately confirms the stretch ratio at which the laminated body breaks, and means a value 0.2 lower than the value.
  • the stretching temperature of the in-air auxiliary stretching can be set to any appropriate value depending on the forming material of the thermoplastic resin substrate, the stretching method and the like.
  • the stretching temperature is preferably the glass transition temperature (Tg) or higher of the thermoplastic resin substrate, more preferably the glass transition temperature (Tg) + 10 ° C. or higher of the thermoplastic resin substrate, and particularly preferably Tg + 15 ° C. or higher.
  • the upper limit of the stretching temperature is preferably 170 ° C.
  • the crystallization index of the PVA-based resin after the in-air auxiliary stretching is preferably 1.3 to 1.8, more preferably 1.4 to 1.7.
  • an insolubilization treatment is performed after the in-air auxiliary stretching treatment and before the underwater stretching treatment or the dyeing treatment.
  • the insolubilization treatment is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution.
  • concentration of the boric acid aqueous solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water.
  • the liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C.
  • the above dyeing treatment is typically performed by dyeing the PVA-based resin layer with a dichroic material (typically iodine). Specifically, it is performed by adsorbing iodine on the PVA resin layer.
  • adsorption method include a method of immersing the PVA-based resin layer (laminate) in a dyeing solution containing iodine, a method of applying the dyeing solution to the PVA-based resin layer, and a method of applying the dyeing solution to the PVA-based resin layer.
  • Examples include a method of spraying.
  • a preferred method is to immerse the laminate in a dyeing solution (dyeing bath). This is because iodine can be favorably adsorbed.
  • the dye solution is preferably an iodine aqueous solution.
  • the iodine content is preferably 0.05 to 0.5 parts by weight with respect to 100 parts by weight of water.
  • iodide examples include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide.
  • potassium iodide is preferable.
  • the content of iodide is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 5 parts by weight, based on 100 parts by weight of water.
  • the temperature of the dyeing solution during dyeing is preferably 20 ° C. to 50 ° C. in order to suppress dissolution of the PVA-based resin.
  • the immersion time is preferably 5 seconds to 5 minutes, more preferably 30 seconds to 90 seconds in order to secure the transmittance of the PVA-based resin layer.
  • the dyeing conditions can be set such that the final transmittance of the polarizing film obtained is 45% or more and the polarization degree is 97% or more.
  • a dyeing condition preferably, an iodine aqueous solution is used as the dyeing solution, and the ratio of the contents of iodine and potassium iodide in the iodine aqueous solution is 1: 5 to 1:20.
  • the ratio of the contents of iodine and potassium iodide in the aqueous iodine solution is preferably 1: 5 to 1:10.
  • the boric acid contained in the treatment bath is mixed in the dyeing bath.
  • the concentration of boric acid in the dyeing bath may change with time, resulting in unstable dyeability.
  • the upper limit of the boric acid concentration in the dyeing bath is preferably 4 parts by weight, more preferably 2 parts by weight, relative to 100 parts by weight of water. Adjusted.
  • the lower limit of the concentration of boric acid in the dyeing bath is preferably 0.1 part by weight, more preferably 0.2 part by weight, still more preferably 0.5 part by weight, relative to 100 parts by weight of water.
  • the dyeing process is performed using a dyeing bath in which boric acid is preliminarily blended. This can reduce the rate of change in boric acid concentration when boric acid in the treatment bath is mixed in the dyeing bath.
  • the amount of boric acid blended in the dyeing bath in advance (that is, the content of boric acid not derived from the treatment bath) is preferably 0.1 part by weight to 2 parts by weight with respect to 100 parts by weight of water. , And more preferably 0.5 to 1.5 parts by weight.
  • a crosslinking treatment is performed after the dyeing treatment and before the underwater stretching treatment.
  • the cross-linking treatment is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution.
  • the concentration of the aqueous boric acid solution is preferably 1 part by weight to 5 parts by weight with respect to 100 parts by weight of water.
  • the iodide content is preferably 1 to 5 parts by weight with respect to 100 parts by weight of water. Specific examples of iodide are as described above.
  • the liquid temperature of the crosslinking bath is preferably 20 ° C. to 50 ° C.
  • the underwater stretching treatment is performed by immersing the laminate in a stretching bath. According to the underwater stretching treatment, stretching can be performed at a temperature lower than the glass transition temperature (typically about 80 ° C.) of the thermoplastic resin substrate or the PVA-based resin layer, and the PVA-based resin layer is crystallized. It is possible to stretch at a high magnification while suppressing the above. As a result, a polarizing film having excellent optical properties can be manufactured.
  • any appropriate method can be adopted as the stretching method of the laminate. Specifically, it may be fixed-end stretching or free-end stretching (for example, a method of uniaxially stretching by passing a laminate between rolls having different peripheral speeds). Preferably, free end stretching is selected. Stretching of the laminate may be performed in one stage or in multiple stages. When performing in multiple stages, the stretching ratio (maximum stretching ratio) of the laminate to be described later is the product of the stretching ratios in each stage.
  • the underwater stretching is preferably performed by immersing the laminate in a boric acid aqueous solution (boric acid underwater stretching).
  • a boric acid aqueous solution boric acid underwater stretching
  • the PVA-based resin layer can be provided with rigidity that can withstand the tension applied during stretching and water resistance that does not dissolve in water.
  • boric acid can generate a tetrahydroxyborate anion in an aqueous solution to crosslink with a PVA-based resin by hydrogen bond.
  • the PVA-based resin layer can be imparted with rigidity and water resistance, can be favorably stretched, and a polarizing film having excellent optical characteristics can be manufactured.
  • the boric acid aqueous solution is preferably obtained by dissolving boric acid and / or borate in water as a solvent.
  • the boric acid concentration is preferably 1 part by weight to 10 parts by weight, more preferably 2.5 parts by weight to 6 parts by weight, particularly preferably 3 parts by weight to 5 parts by weight, relative to 100 parts by weight of water. Is.
  • concentration of boric acid By setting the concentration of boric acid to 1 part by weight or more, dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizing film with higher characteristics can be manufactured.
  • an aqueous solution obtained by dissolving a boron compound such as borax, glyoxal, glutaraldehyde, or the like in a solvent can also be used.
  • iodide is added to the above stretching bath (boric acid aqueous solution).
  • iodide elution of iodine adsorbed on the PVA-based resin layer can be suppressed.
  • Specific examples of iodide are as described above.
  • the concentration of iodide is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 8 parts by weight with respect to 100 parts by weight of water.
  • the stretching temperature (liquid temperature of the stretching bath) is preferably 40 ° C to 85 ° C, more preferably 60 ° C to 75 ° C. At such a temperature, the PVA-based resin layer can be stretched at a high magnification while suppressing the dissolution.
  • the glass transition temperature (Tg) of the thermoplastic resin substrate is preferably 60 ° C. or higher in relation to the formation of the PVA-based resin layer. In this case, if the stretching temperature is lower than 40 ° C., it may not be possible to stretch well even if the plasticization of the thermoplastic resin substrate by water is taken into consideration.
  • the higher the temperature of the stretching bath the higher the solubility of the PVA-based resin layer, and there is a possibility that excellent optical characteristics may not be obtained.
  • the immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes.
  • Draw ratio by underwater drawing is preferably 1.5 times or more, more preferably 3.0 times or more.
  • the total draw ratio of the laminated body is preferably 5.0 times or more, more preferably 5.5 times or more, with respect to the original length of the laminated body.
  • Such a high draw ratio can be achieved by adopting an underwater drawing method (boric acid underwater drawing).
  • the drying shrinkage treatment may be performed by zone heating performed by heating the entire zone, or may be performed by heating the transport roll (using a so-called heating roll) (heating roll drying method). Both are preferably used.
  • a heating roll By drying using a heating roll, it is possible to efficiently suppress the curling of the laminate by heating and to produce a polarizing film having an excellent appearance.
  • the crystallization of the thermoplastic resin substrate can be efficiently promoted to increase the crystallinity, which is relatively low. Even at the drying temperature, the crystallinity of the thermoplastic resin substrate can be satisfactorily increased.
  • the rigidity of the thermoplastic resin base material increases, and the thermoplastic resin base material can withstand the shrinkage of the PVA-based resin layer due to drying, and curling is suppressed.
  • the laminate can be dried while being kept flat, so that not only curling but also wrinkling can be suppressed.
  • the laminated body can be improved in optical characteristics by shrinking in the width direction by a drying shrinkage treatment. This is because the orientation of PVA and the PVA / iodine complex can be effectively enhanced.
  • the shrinkage ratio in the width direction of the laminate by the dry shrinkage treatment is preferably 1% to 10%, more preferably 2% to 8%, and particularly preferably 4% to 6%.
  • FIG. 3 is a schematic diagram showing an example of the drying shrinkage treatment.
  • the laminate 200 is dried while being transported by the transport rolls R1 to R6 heated to a predetermined temperature and the guide rolls G1 to G4.
  • the transport rolls R1 to R6 are arranged so as to alternately and continuously heat the surface of the PVA resin layer and the surface of the thermoplastic resin substrate.
  • one surface of the laminate 200 for example, thermoplastic
  • the transport rolls R1 to R6 may be arranged so that only the resin substrate surface) is continuously heated.
  • the drying conditions can be controlled by adjusting the heating temperature of the transfer rolls (heating roll temperature), the number of heating rolls, the contact time with the heating rolls, and the like.
  • the temperature of the heating roll is preferably 60 ° C to 120 ° C, more preferably 65 ° C to 100 ° C, and particularly preferably 70 ° C to 80 ° C.
  • the crystallinity of the thermoplastic resin can be favorably increased, curling can be favorably suppressed, and an optical laminate having extremely excellent durability can be manufactured.
  • the temperature of the heating roll can be measured with a contact thermometer. In the illustrated example, six transport rolls are provided, but there is no particular limitation as long as there are multiple transport rolls.
  • the number of transport rolls is usually 2 to 40, preferably 4 to 30.
  • the contact time (total contact time) between the laminate and the heating roll is preferably 1 second to 300 seconds, more preferably 1 to 20 seconds, and further preferably 1 to 10 seconds.
  • the heating roll may be provided in a heating furnace (for example, an oven) or may be provided in a normal production line (under room temperature environment). Preferably, it is provided in a heating furnace equipped with a blowing means.
  • a heating furnace equipped with a blowing means.
  • the temperature of hot air drying is preferably 30 ° C to 100 ° C.
  • the hot air drying time is preferably 1 to 300 seconds.
  • the wind speed of the hot air is preferably about 10 m / s to 30 m / s. The wind speed is the wind speed in the heating furnace, and can be measured by a mini vane type digital anemometer.
  • a washing treatment is performed after the underwater stretching treatment and before the drying shrinkage treatment.
  • the cleaning treatment is typically performed by immersing the PVA-based resin layer in an aqueous potassium iodide solution.
  • the first retardation layer 20 may have any appropriate optical property and / or mechanical property depending on the purpose.
  • the first retardation layer 20 typically has a slow axis.
  • the angle ⁇ formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizing film 11 is 40 ° to 50 ° as described above, preferably 42 ° to 48 °. And more preferably about 45 °. If the angle ⁇ is in such a range, by using the ⁇ / 4 plate as the first retardation layer as described later, very excellent circular polarization characteristics (as a result, very excellent antireflection characteristics) A polarizing plate with a retardation layer having is obtained.
  • the first retardation layer preferably has a refractive index characteristic of nx> ny ⁇ nz.
  • the first retardation layer is typically provided to impart antireflection characteristics to the polarizing plate, and can function as a ⁇ / 4 plate in one embodiment.
  • the in-plane retardation Re (550) of the first retardation layer is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, still more preferably 130 nm to 160 nm.
  • the Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, further preferably 0.9 to 1.5, particularly preferably 0.9 to 1. It is 3. By satisfying such a relationship, a very excellent reflective hue can be achieved when the obtained polarizing plate with a retardation layer is used in an image display device.
  • the first retardation layer may exhibit an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It may be shown, or may exhibit a flat wavelength dispersion characteristic in which the phase difference value hardly changes even with the wavelength of the measurement light.
  • the first retardation layer exhibits an inverse dispersion wavelength characteristic.
  • 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, it is possible to realize a very excellent antireflection characteristic.
  • the absolute value of the photoelastic coefficient of the first retardation layer is preferably 2 ⁇ 10 ⁇ 11 m 2 / N or less, more preferably 2.0 ⁇ 10 ⁇ 13 m 2 / N to 1.5 ⁇ 10 ⁇ 11. m 2 / N, more preferably from 1.0 ⁇ 10 -12 m 2 /N ⁇ 1.2 ⁇ 10 -11 m 2 / N resin.
  • the absolute value of the photoelastic coefficient is in such a range, it is difficult for the phase difference to change when contraction stress occurs during heating. As a result, heat unevenness of the obtained image display device can be favorably prevented.
  • the first retardation layer is typically composed of a stretched film of a resin film.
  • the thickness of the first retardation layer is preferably 70 ⁇ m or less, more preferably 45 ⁇ m to 60 ⁇ m.
  • the thickness of the first retardation layer is preferably 40 ⁇ m or less, more preferably 10 ⁇ m to 40 ⁇ m. And more preferably 20 ⁇ m to 30 ⁇ m.
  • the first retardation layer 20 may be composed of any appropriate resin film that can satisfy the above characteristics.
  • resins include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins. , A polyimide resin, a polyether resin, a polystyrene resin, and an acrylic resin. These resins may be used alone or in combination (for example, blending or copolymerization).
  • a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be preferably used.
  • a polycarbonate-based resin is 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-based resin is a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / or di, tri or polyethylene glycol. And 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 a di-, tri-, or polyethylene glycol. .
  • the polycarbonate-based resin may include a structural unit derived from another dihydroxy compound, if necessary.
  • the glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 150 ° C. or lower, and more preferably 120 ° C. or higher and 140 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to be poor, dimensional change may occur after film formation, and the image quality of the obtained organic EL panel may be deteriorated. If the glass transition temperature is excessively high, the molding stability during film molding may be deteriorated, and the transparency of the film may be impaired.
  • the glass transition temperature is calculated according to JIS K 7121 (1987).
  • the molecular weight of the polycarbonate resin can be represented by reduced viscosity.
  • the reduced viscosity is measured using a Ubbelohde viscosity tube at a temperature of 20.0 ° C. ⁇ 0.1 ° C. by precisely adjusting the polycarbonate concentration to 0.6 g / dL using methylene chloride as a solvent.
  • 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, further preferably 0.80 dL / g.
  • the reduced viscosity is smaller than the lower limit, there may occur a problem that the mechanical strength of the molded product becomes small.
  • the reduced viscosity is higher than the upper limit value, the fluidity at the time of molding may be lowered, and the productivity and the moldability may be lowered.
  • a commercially available film may be used as the polycarbonate resin film.
  • Specific examples of commercially available products include Teijin's product names “Pure Ace WR-S”, “Pure Ace WR-W”, “Pure Ace WR-M”, and Nitto Denko's product name “NRF”.
  • the first retardation layer 20 is obtained, for example, by stretching a film formed of the above polycarbonate resin.
  • Any appropriate molding method can be adopted as a method of forming a film from the polycarbonate-based resin. Specific examples include compression molding method, transfer molding method, injection molding method, extrusion molding method, blow molding method, powder molding method, FRP molding method, cast coating method (for example, casting method), calender molding method, hot press. Law etc. are mentioned.
  • An extrusion molding method or a cast coating method is preferable. This is because the smoothness of the obtained film can be improved and good optical uniformity can be obtained.
  • the molding conditions can be appropriately set according to the composition and type of the resin used, the characteristics desired for the retardation layer, and the like. As described above, since many film products of the polycarbonate-based resin are commercially available, the commercially available film may be directly subjected to the stretching treatment.
  • the thickness of the resin film can be set to any appropriate value depending on the desired thickness of the first retardation layer, desired optical characteristics, stretching conditions described below, and the like.
  • the thickness is preferably 50 ⁇ m to 300 ⁇ m.
  • Any appropriate stretching method and stretching conditions can be adopted for the above stretching.
  • various stretching methods such as free-end stretching, fixed-end stretching, free-end contraction, and fixed-end contraction can be used alone or simultaneously or sequentially.
  • the stretching direction can also be performed in various directions and dimensions such as the length direction, the width direction, the thickness direction, and the oblique direction.
  • the stretching temperature is preferably Tg-30 ° C. to Tg + 60 ° C., more preferably Tg-10 ° C. to Tg + 50 ° C., with respect to the glass transition temperature (Tg) of the resin film.
  • the retardation film is produced by uniaxially stretching a resin film or uniaxially stretching a fixed end.
  • a specific example of the fixed-end uniaxial stretching is a method of stretching the resin film in the width direction (transverse direction) while running the resin film in the longitudinal direction.
  • the stretching ratio is preferably 1.1 times to 3.5 times.
  • the retardation film can be produced by continuously stretching a long resin film in the direction of the angle ⁇ with respect to the longitudinal direction.
  • a long stretched film having an orientation angle of ⁇ with respect to the longitudinal direction of the film (a slow axis in the direction of angle ⁇ ) can be obtained.
  • Roll-to-roll is possible, and the manufacturing process can be simplified.
  • the angle ⁇ may be an angle formed by the absorption axis of the polarizing film and the slow axis of the retardation layer in the polarizing plate with the retardation layer.
  • the angle ⁇ is, as described above, preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and further preferably about 45 °.
  • a stretching machine used for oblique stretching for example, a tenter type stretching machine capable of applying a feeding force or a pulling force or a pulling force at different speeds in the lateral and / or longitudinal directions can be mentioned.
  • the tenter type stretching machine include a horizontal uniaxial stretching machine and a simultaneous biaxial stretching machine, but any appropriate stretching machine may 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 a slow axis in the desired direction (substantially long Phase-difference film) can be obtained.
  • the stretching temperature of the above-mentioned film may 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 + 30 ° C, more preferably Tg-15 ° C to Tg + 15 ° C, and most preferably Tg-10 ° C to Tg + 10 ° C. By stretching at such a temperature, the first retardation layer having suitable properties in the present invention can be obtained.
  • Tg is a glass transition temperature of the constituent material of the film.
  • the retardation Rth (550) in the thickness direction of the second retardation layer is preferably ⁇ 50 nm to ⁇ 300 nm, more preferably ⁇ 70 nm to ⁇ 250 nm, further preferably ⁇ 90 nm to ⁇ 200 nm, particularly preferably -100 nm to -180 nm.
  • the second retardation layer preferably comprises a film containing a liquid crystal material fixed in homeotropic alignment.
  • the liquid crystal material (liquid crystal compound) capable of homeotropic alignment may be a liquid crystal monomer or a liquid crystal polymer.
  • Specific examples of the method of forming the liquid crystal compound and the retardation layer include the liquid crystal compound and the method of forming the retardation layer described in JP-A-2002-333642, [0020] to [0028].
  • the thickness of the second retardation layer is preferably 0.5 ⁇ m to 10 ⁇ m, more preferably 0.5 ⁇ m to 8 ⁇ m, and further preferably 0.5 ⁇ m to 5 ⁇ m.
  • the conductive layer is formed by any appropriate film formation method (eg, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It may be formed by depositing a metal oxide film thereon.
  • the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin complex oxide, tin-antimony complex oxide, zinc-aluminum complex oxide, and indium-zinc complex 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 above-mentioned base material to the first retardation layer (or the second retardation layer, if present), and the conductive layer alone may serve as the constituent layer of the polarizing plate with the retardation layer.
  • it may be laminated on the first retardation layer (or the second retardation layer, if present) as a laminate with the substrate (substrate with conductive layer).
  • the above-mentioned substrate is optically isotropic, so that the conductive layer can be used as a isotropic substrate with a conductive layer in a polarizing plate with a retardation layer.
  • any suitable isotropic substrate can be adopted.
  • the material forming the isotropic substrate include, for example, a material having a resin having no conjugated system such as norbornene-based resin or olefin-based resin as a main skeleton, and a cyclic structure such as a lactone ring or a glutarimide ring of an acrylic resin. Materials included in the main chain are included. When such a material is used, it is possible to suppress the development of retardation due to the orientation of the molecular chains when forming the isotropic substrate.
  • 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 substrate with the conductive layer may be patterned as required. By patterning, conductive parts and insulating parts can be formed. As a result, electrodes can be formed.
  • the electrodes may function as touch sensor electrodes that sense a touch on 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 polarizing plate with a retardation layer described in the above items A to E can be applied to an image display device. Therefore, the present invention includes an image display device using such a polarizing plate with a retardation layer.
  • Typical examples of the image display device include a liquid crystal display device and an electroluminescence (EL) display device (for example, an organic EL display device and an inorganic EL display device).
  • the image display device according to the embodiment of the present invention includes the polarizing plate with a retardation layer described in the above items A to E on the viewing side.
  • the polarizing plate with a retardation layer is laminated such that the retardation layer is on the image display cell (for example, liquid crystal cell, organic EL cell, inorganic EL cell) side (the polarizing film is on the viewing side).
  • the image display device has a curved shape (substantially a curved display screen) and / or is bendable or foldable. In such an image display device, the effect of the polarizing plate with a retardation layer of the present invention becomes remarkable.
  • the measuring method of each characteristic is as follows. Unless otherwise specified, "parts" and “%” in the examples and comparative examples are based on weight.
  • Thickness The thickness of 10 ⁇ m or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name “MCPD-3000”). The thickness exceeding 10 ⁇ m was measured using a digital micrometer (manufactured by Anritsu Corporation, product name “KC-351C”).
  • the laminate (polarizing plate) of the polarizing film / protective layer used in Examples and Comparative Examples was measured using an ultraviolet-visible spectrophotometer (V-7100 manufactured by JASCO Corporation).
  • the single-piece transmittance Ts, the parallel transmittance Tp, and the orthogonal transmittance Tc are defined as Ts, Tp, and Tc of the polarizing film, respectively.
  • These Ts, Tp and Tc are Y values measured by the 2 degree visual field (C light source) of JIS Z8701 and subjected to the luminosity correction.
  • the refractive index of the protective layer was 1.50, and the refractive index of the surface of the polarizing film opposite to the protective layer was 1.53.
  • the degree of polarization P was calculated from the obtained Tp and Tc by the following formula.
  • Polarization degree P (%) ⁇ (Tp-Tc) / (Tp + Tc) ⁇ 1/2 ⁇ 100
  • the spectrophotometer can also perform the same measurement by using LPF-200 manufactured by Otsuka Electronics Co., Ltd.
  • Table 1 shows the measured values of the single-body transmittance Ts and the polarization degree P obtained by the measurement using V-7100 and LPF-200 for the polarizing plate samples 1 to 3 having the same configurations as the following examples. Show.
  • the difference between the measured single transmittance of V-7100 and the measured single transmittance of LPF-200 was 0.1% or less, and any spectrophotometer was used. It can be seen that the same measurement result can be obtained even in the case. Note that, for example, when a polarizing plate provided with an adhesive having an anti-glare (AG) surface treatment or a diffusion property is used as a measurement target, different measurement results may be obtained depending on the spectrophotometer, but in this case, the same measurement result is obtained. It is possible to compensate for the difference in the measured values depending on the spectrophotometer by performing the numerical conversion based on the measured values when the polarizing plate is measured by each spectrophotometer.
  • AG anti-glare
  • the single-piece transmittances at a total of 5 positions in the vicinity of the center of each of the four sides of the measurement sample, approximately 1.5 cm to 2.0 cm inward from the midpoint, and in the center are the same as in (2) above. Measured. Next, the difference between the maximum value and the minimum value of the single-element transmittance measured at each measurement position was calculated, and this value was used as the variation in the optical characteristics of the sheet-shaped polarizing film. (5) Warpage The polarizing plate with a retardation layer obtained in each of Examples and Comparative Examples was cut out into a size of 110 mm ⁇ 60 mm. At this time, the polarizing film was cut out so that the absorption axis direction was the long side direction.
  • the cut out polarizing plate with a retardation layer was attached to a glass plate of 120 mm ⁇ 70 mm size and 0.2 mm thickness via an adhesive to give a test sample.
  • the test sample was placed in a heating oven maintained at 85 ° C. for 24 hours, and the amount of warp after taking out was measured. When the test sample was allowed to stand on a flat surface with the glass plate facing down, the height of the highest portion from the flat surface was defined as the amount of warpage.
  • (6) Bending durability The polarizing plates with retardation layers obtained in Examples and Comparative Examples were cut into a size of 50 mm x 100 mm. At this time, the polarizing film was cut out so that the absorption axis direction was the short side direction.
  • the cut out polarizing plate with a retardation layer was subjected to a bending test under the condition of 20 ° C. and 50% RH. Specifically, the polarizing plate with a retardation layer, so that the retardation layer side is the outer side, repeatedly bent in a direction parallel to the absorption axis direction, such as cracks that cause display defects, peeling or film breakage, etc. The number of times of bending before occurrence was measured and evaluated according to the following criteria (bending diameter: 2 mm ⁇ ).
  • Elastic modulus A film to be measured is subjected to a tensile test with a parallel part width of 10 mm and a length of 40 mm based on JIS K6734: 2000. It was molded into a dumbbell and subjected to a tensile test according to JIS K7161: 1994 to determine the tensile elastic modulus.
  • the length direction usually coincides with the stretching direction of the polarizing film.
  • Example 1 Preparation of Polarizing Film
  • an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 ⁇ m) having a long shape, a water absorption of 0.75% and a Tg of about 75 ° C. was used as the thermoplastic resin substrate. Corona treatment was applied to one surface of the resin substrate.
  • Polyvinyl alcohol (polymerization degree: 4200, saponification degree: 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephimmer Z410") in a ratio of 9: 1 100 weight of PVA-based resin
  • 13 parts by weight of potassium iodide was added and dissolved in water to prepare a PVA aqueous solution (coating solution).
  • the PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 ⁇ m, and a laminate was prepared.
  • the obtained laminated body was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130 ° C. (in-air auxiliary stretching treatment).
  • the laminated body was immersed in an insolubilizing bath having a liquid temperature of 40 ° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
  • a dyeing bath having a liquid temperature of 30 ° C.
  • the total draw ratio was 5.5 in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds.
  • Uniaxial stretching was performed so as to double the length (underwater stretching treatment).
  • the laminate was immersed in a cleaning bath having a liquid temperature of 20 ° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
  • cleaning treatment while being dried in an oven kept at 90 ° C., it was brought into contact with a SUS heating roll whose surface temperature was kept at 75 ° C. for about 2 seconds (dry shrinkage treatment).
  • the shrinkage ratio in the width direction of the laminate due to the dry shrinkage treatment was 5.2%. In this way, a polarizing film having a thickness of 5.0 ⁇ m was formed on the resin base material.
  • a cycloolefin film with a hard coat layer (refractive index 1.53) as a protective layer were bonded via an ultraviolet curable adhesive.
  • the curable adhesive was applied so that the total thickness was 1.0 ⁇ m, and the curable adhesive was pasted using a roll machine. Then, UV rays were irradiated from the protective layer side to cure the adhesive.
  • the resin substrate was peeled off to obtain a long-sized polarizing plate (width: 1300 mm) having a structure of protective layer / adhesive layer / polarizing film.
  • the single transmittance of the polarizing plate (substantially, the polarizing film) was 45.37%, and the polarization degree was 98.083%. Further, the variation of the optical properties of the long polarizing film was 0.25%, and the variation of the optical properties of the single-leaf polarizing film was 0.07%.
  • the temperature rise and pressure reduction in the second reactor were started, and the internal temperature was set to 240 ° C. and the pressure was set to 0.2 kPa in 50 minutes. Then, the polymerization was allowed to proceed until a predetermined stirring power was obtained. When the predetermined power was reached, nitrogen was introduced into the reactor to restore the pressure, the produced polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets.
  • Example 2-1 Production of Polarizing Film A polarizing film having a thickness of 5.0 ⁇ m was formed on the resin substrate in the same manner as in Example 1.
  • a protective layer was prepared in the same manner as in Example 1 except that a triacetyl cellulose (TAC) film with a hard coat layer (hard coat thickness 7 ⁇ m, TAC thickness 25 ⁇ m, elastic modulus: 3600 MPa) was used as the protective layer.
  • TAC triacetyl cellulose
  • a polarizing plate having a structure of adhesive layer / polarizing film was produced.
  • the obtained long resin film was stretched 2.8 times in the width direction at 138 ° C. while adjusting so as to obtain a predetermined retardation to obtain a retardation film having a thickness of 38 ⁇ m.
  • the Re (550) of the obtained retardation film was 144 nm, and the Re (450) / Re (550) was 0.86.
  • Example 2-2 A long polyester carbonate resin film having a thickness of 105 ⁇ m obtained in the same manner as in Example 2-1 was stretched in the width direction while adjusting so as to obtain a predetermined retardation, to give a retardation film having a thickness of 38 ⁇ m. Obtained.
  • the Re (550) of the obtained retardation film was 140 nm.
  • Got The total thickness of the obtained polarizing plate with a retardation layer was 81 ⁇ m.
  • the obtained polarizing plate with retardation layer was subjected to the same evaluations as in Example 1. The results are shown in Table 2.
  • Example 2-3 A long polyester carbonate resin film having a thickness of 105 ⁇ m obtained in the same manner as in Example 2-1 was stretched in the width direction while adjusting so as to obtain a predetermined retardation, to give a retardation film having a thickness of 38 ⁇ m. Obtained.
  • the Re (550) of the obtained retardation film was 149 nm.
  • Got The total thickness of the obtained polarizing plate with a retardation layer was 81 ⁇ m.
  • the obtained polarizing plate with retardation layer was subjected to the same evaluations as in Example 1. The results are shown in Table 2.
  • Example 3 The polycarbonate resin film obtained in the same manner as in Example 1 was obliquely stretched by a method according to Example 2 in JP-A-2014-194483 to obtain a retardation film having a thickness of 58 ⁇ m.
  • the Re (550) of the obtained retardation film was 144 nm
  • the Re (450) / Re (550) was 0.86
  • the Nz coefficient was 1.21
  • the orientation angle (the direction of the slow axis). was 45 ° with respect to the longitudinal direction.
  • This retardation film and the polarizing plate of Example 1 were laminated by roll-to-roll via an acrylic pressure-sensitive adhesive (thickness 5 ⁇ m) to form a protective layer / adhesive layer / polarizing film / adhesive layer / retardation layer.
  • the obtained polarizing plate with a retardation layer was obtained.
  • the total thickness of the obtained polarizing plate with a retardation layer was 97 ⁇ m.
  • the obtained polarizing plate with retardation layer was subjected to the same evaluations as in Example 1.
  • the amount of warpage was 4.1 mm. The results are shown in Table 2.
  • the original polyvinyl alcohol film (polyvinyl alcohol film which was not stretched at all in the transport direction) was stretched 3.7 times in the transport direction (dyeing step).
  • the immersion time at this time was about 60 seconds.
  • the dyed polyvinyl alcohol film in a crosslinking bath at 40 ° C. (an aqueous solution having a boric acid concentration of 3.0 wt% and a potassium iodide concentration of 3.0 wt%)
  • the original polyvinyl alcohol film was immersed. It was stretched to 4.2 times in the transport direction based on the standard (crosslinking step). Further, the obtained polyvinyl alcohol film was immersed in a stretching bath at 64 ° C.
  • Polarizing Plate As an adhesive, a polyvinyl alcohol resin containing an acetoacetyl group (average polymerization degree: 1,200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) and methylolmelamine were used. The containing aqueous solution was used.
  • a triacetyl cellulose (TAC) film with a hard coat layer (hard coat thickness 7 ⁇ m, TAC A thickness of 25 ⁇ m and an elastic modulus of 3600 MPa was applied to the other surface of the polarizer with a 25 ⁇ m-thick TAC film using a roll bonding machine, and then heat-dried in an oven (temperature: 60 ° C., time: 5 minutes).
  • TAC triacetyl cellulose
  • the direction of the orientation treatment was set to be 15 ° with respect to the direction of the absorption axis of the polarizer when it was attached to the polarizing plate, as viewed from the viewing side.
  • the liquid crystal coating liquid was applied to the surface of the alignment treatment by a bar coater, and the liquid crystal compound was aligned by heating and drying at 90 ° C. for 2 minutes.
  • the liquid crystal layer thus formed was irradiated with light of 1 mJ / cm 2 using a metal halide lamp to cure the liquid crystal layer, thereby forming a liquid crystal alignment solidified layer A on the PET film.
  • the thickness of the liquid crystal alignment fixed layer A was 2.5 ⁇ m, and the in-plane retardation Re (550) was 270 nm.
  • the coating thickness was changed and the orientation treatment direction was set to be the direction of 75 ° with respect to the absorption axis direction of the polarizer when viewed from the viewing side.
  • a liquid crystal alignment fixed layer B was formed.
  • the thickness of the liquid crystal alignment fixed layer B was 1.5 ⁇ m, and the in-plane retardation Re (550) was 140 nm.
  • Re (450) / Re (550) of the liquid crystal alignment fixed layers A and B was 1.11.
  • protective layer 1 / adhesive layer / polarizer / adhesive layer / protective layer 2 / adhesive layer / retardation layer (first orientation solidification layer / adhesion layer / second orientation solidification layer) is provided.
  • a polarizing plate with a retardation layer was obtained.
  • the total thickness of the obtained polarizing plate with a retardation layer was 75 ⁇ m.
  • the obtained polarizing plate with retardation layer was subjected to the same evaluations as in Example 1. The results are shown in Table 2.
  • Example 3 Example except that potassium iodide was not added to the PVA aqueous solution (coating solution), the draw ratio in the in-air auxiliary drawing process was set to 1.8 times, and no heating roll was used in the dry shrinking process. An attempt was made to produce a polarizing film in the same manner as in Example 1, but the PVA resin layer was dissolved in the dyeing treatment and the underwater stretching treatment, and the polarizing film could not be produced. Therefore, a polarizing plate with a retardation layer could not be prepared.
  • the example of the present invention is excellent in the optical characteristics of the polarizing film and can significantly suppress the warpage after the heating test.
  • the layer thickness of the polarizing plate is 85 ⁇ m or less, and a substrate having an elastic modulus of 3000 MPa or more, preferably a TAC film is used as a protective layer, the bending property is further improved. Can improve.
  • the polarizing plate with a retardation layer of the present invention is suitably used as a circular polarizing plate for liquid crystal display devices, organic EL display devices and inorganic EL display devices.
  • Reference Signs List 10 polarizing plate 11 polarizing film 12 first protective layer 13 second protective layer 20 retardation layer 100 retardation layer-attached polarizing plate 101 retardation layer-attached polarizing plate

Abstract

La présente invention concerne une plaque de polarisation mince avec une couche de retard, ladite plaque de polarisation ayant d'excellentes propriétés de manipulation et d'excellentes caractéristiques optiques. Une plaque de polarisation avec une couche de retard selon la présente invention comprend : une plaque de polarisation qui comprend un film de polarisation et une couche de protection qui est disposée sur au moins un côté du film de polarisation ; et une couche de retard. Le film de polarisation est constitué d'un film de résine d'alcool polyvinylique qui contient une substance dichroïque ; et le film de polarisation a une épaisseur de 8 µm ou moins, une transmittance unique de 45 % ou plus et un degré de polarisation de 97 % ou plus. La couche de retard a une Re(550) de 100 nm à 190 nm, la valeur de Re(450)/Re(550) étant supérieure ou égale à 0,8 mais inférieure à 1. L'angle entre l'axe lent de la couche de retard et l'axe d'absorption du film de polarisation est de 40° à 50°.
PCT/JP2019/039638 2018-10-15 2019-10-08 Plaque de polarisation avec couche de retard et dispositif d'affichage d'image l'utilisant WO2020080186A1 (fr)

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WO2017073638A1 (fr) * 2015-10-27 2017-05-04 日本合成化学工業株式会社 Film à base d'alcool polyvinylique ainsi que pellicule polarisante mettant en œuvre celui-ci, plaque de polarisation, et procédé de fabrication de film à base d'alcool polyvinylique
JP2017090700A (ja) * 2015-11-11 2017-05-25 住友化学株式会社 偏光板及びｉｐｓモード液晶表示装置
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Publication number Priority date Publication date Assignee Title
JP2006111797A (ja) * 2004-10-18 2006-04-27 Konica Minolta Opto Inc 光学フィルム、偏光板及び液晶表示装置
JP2012032418A (ja) * 2008-11-19 2012-02-16 Sharp Corp 円偏光板及び表示装置
JP2017068282A (ja) * 2010-09-03 2017-04-06 日東電工株式会社 偏光膜、偏光膜を含む光学フィルム積層体、及び、偏光膜を含む光学フィルム積層体の製造に用いるための延伸積層体、並びにそれらの製造方法、並びに偏光膜を有する有機ｅｌ表示装置
JP2015191224A (ja) * 2014-03-31 2015-11-02 日東電工株式会社 延伸積層体の製造方法および延伸積層体、ならびに偏光膜の製造方法および偏光膜
WO2016088683A1 (fr) * 2014-12-01 2016-06-09 合同会社Ｓｎパートナーズ Dispositif d'affichage d'image à flottement libre
JP2017049363A (ja) * 2015-08-31 2017-03-09 日東電工株式会社 光学補償層付偏光板およびそれを用いた有機ｅｌパネル
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JP2017090700A (ja) * 2015-11-11 2017-05-25 住友化学株式会社 偏光板及びｉｐｓモード液晶表示装置
WO2019054272A1 (fr) * 2017-09-13 2019-03-21 日東電工株式会社 Plaque polarisante, rouleau de plaque polarisante, et procédé de production de film polarisant

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