JP2016126130A - Laminate for organic el display device and organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminate for an organic EL display device including such an optical laminate that has flexibility and is bendable while including a polarizing film, a protective film of the polarizing film, and a retardation film, and a bendable organic EL display device that includes the above laminate for an organic EL display device.SOLUTION: The laminate for an organic EL display device comprises an optical laminate and a first stress relief layer. The optical laminate includes: a polarizing film made of a polyvinyl alcohol resin having a thickness of 12 μm or less, in which a dichroic substance is oriented; a protective film made of a transparent resin material joined to a first surface of the polarizing film; and a retardation film joined to a second surface different from the first surface of the polarizing film. The first stress relief layer shows a storage modulus of 0.05 to 0.15 MPa at 25°C, and is disposed on an opposite side of the protective film to the retardation film. The optical laminate has a thickness of 120 μm or less, and is configured to be bendable.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a laminate for an organic EL display device including a bendable optical laminate having a polarizing film, and a bendable organic EL display device including such a laminate for an organic EL display device. .

  A touch sensor-integrated organic EL display device is conventionally known as disclosed in, for example, Patent Document 1. In the organic EL display device of Patent Document 1, as shown in FIG. 1, an optical laminate 920 is provided on the viewing side of the organic EL display panel 901, and a touch panel 930 is provided on the viewing side of the optical laminate 920. ing. The optical laminate 920 includes a polarizing film 921 and a retardation film 923 having protective films 922-1 and 922-2 bonded on both sides, and the polarizing film 921 is provided on the viewing side of the retardation film 923. The touch panel 930 includes transparent conductive films 916-1 and 916-2 having a structure in which base film 915-1 and 915-2 and transparent conductive layers 912-1 and 912-2 are stacked via a spacer 917. It has an arranged structure.

  On the other hand, in recent years, it is expected to realize a foldable organic EL display device which is an organic EL display device which is more portable.

JP 2014-157745 A

  However, for example, a conventional organic EL display device as disclosed in Patent Document 1 is not designed with bending in mind. If a plastic film is used for the organic EL display panel substrate, the organic EL display panel can be bent. However, the polarizing film of the conventional organic EL display device laminated on the organic EL display panel, its protective film, The optical layered body in which the phase difference films are stacked inhibits the flexibility of the organic EL display device.

  Therefore, the present invention provides a laminate for an organic EL display device including the optical laminate, which imparts flexibility to the optical laminate including the polarizing film, the protective film thereof, and the retardation film, and enables the bending. An object is to realize a foldable organic EL display device including a laminate for an organic EL display device.

  One aspect of the present invention includes an optical laminate and a first stress relaxation layer, and the optical laminate comprises a polarizing film made of a polyvinyl alcohol resin having a thickness of 12 μm or less in which a dichroic material is oriented. A transparent resin material protective film bonded to the first surface of the polarizing film, and a retardation film bonded to a second surface different from the first surface of the polarizing film, The stress relaxation layer 1 has a storage elastic modulus at 25 ° C. of 0.05 to 0.15 MPa, is disposed on the opposite side of the retardation film with respect to the protective film, and the thickness of the optical laminate is The laminate for an organic EL display device, wherein the optical laminate is configured to be bendable, is 120 μm or less.

  In one embodiment of this aspect, a foldable transparent conductive layer constituting a touch sensor may be further disposed on the opposite side of the retardation film from the protective film.

  In this case, a second stress relaxation layer may be further disposed on the side opposite to the retardation film with respect to the transparent conductive layer.

  In one embodiment of this aspect, a foldable transparent conductive layer constituting a touch sensor can be further disposed between the protective film and the first stress relaxation layer.

  In this case, a second stress relaxation layer may be further disposed on the opposite side of the retardation film from the protective film.

  Another aspect of the present invention includes the above-described laminate for an organic EL display device and an organic EL display panel configured to be bendable, and is for the organic EL display device on the viewing side with respect to the organic EL display panel. The present invention provides an organic EL display device in which a laminated body is arranged and configured to be bendable.

  In one embodiment of this aspect, a window can be arranged on the viewing side with respect to the laminate for an organic EL display device.

  According to the present invention, a laminate for an organic EL display device including the optical laminate, which is capable of bending and bending the optical laminate including the polarizing film, the protective film thereof, and the retardation film, and the like. A foldable organic EL display device including a laminate for an organic EL display device can be realized.

  Hereinafter, embodiments of an optical laminate according to the present invention will be described in detail with reference to the drawings.

It is sectional drawing which shows the conventional organic EL display apparatus. It is sectional drawing which shows the organic electroluminescent display apparatus by one Embodiment of this invention. It is sectional drawing which shows the organic electroluminescence display by another embodiment of this invention. It is sectional drawing which shows the organic electroluminescence display by another embodiment of this invention. It is a figure which shows the manufacturing method of the phase difference film used for one Example. It is a figure which shows the manufacturing method of the phase difference film used for another Example. It is a figure which shows the measuring method of bending strength.

[Laminated body for organic EL display device]
The laminate for an organic EL display device of the present invention includes an optical laminate and a first stress relaxation layer.

[Optical laminate]
The optical layered body of the present invention includes a polarizing film made of a polyvinyl alcohol resin having a thickness of 12 μm or less in which a dichroic material is oriented, a protective film made of a transparent resin material bonded to the first surface of the polarizing film, A retardation film bonded to a second surface different from the first surface of the polarizing film.

  The thickness of the optical layered body of the present invention is 120 μm or less.

  The optical layered body of the present invention is configured to be bendable.

<Polarizing film>
For the polarizing film used in the optical layered body of the present invention, a polyvinyl alcohol-based resin oriented with iodine and stretched by a stretching process such as air stretching (dry stretching) or boric acid-water stretching process can be used.

  As a method for producing a polarizing film, typically, as described in JP-A-2004-341515, a production method (single layer stretching method) including a step of dyeing a single layer of a PVA resin and a step of stretching. ) JP-A-51-069644, JP-A-2000-338329, JP-A-2001-343521, International Publication No. 2010/100917, JP-A-2012-073563, JP-A-2011-2816. The manufacturing method including the process of extending | stretching the PVA-type resin layer and the extending | stretching resin base material in the state of a laminated body, and the process of dyeing | staining as described in (1) is mentioned. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

  The production method including the step of stretching in the state of the laminate and the step of dyeing is as described in JP-A-51-069644, JP-A-2000-338329, and JP-A-2001-343521. There is an aerial stretching (dry stretching) method. And the process of extending | stretching in boric-acid aqueous solution as described in international publication 2010/100917 and Unexamined-Japanese-Patent No. 2012-073563 can be extended at high magnification and can improve polarization | polarized-light performance. A production method including the step of performing air-assisted auxiliary stretching before stretching in a boric acid aqueous solution as described in JP 2012-073563 A is particularly preferable. In addition, as described in JP2011-2816A, a PVA-based resin layer and a stretching resin substrate are stretched in the state of a laminate, and then the PVA-based resin layer is excessively dyed and then decolorized. (Over-staining and decoloring method) is also preferable. The polarizing film used in the optical layered body of the present invention is composed of a polyvinyl alcohol resin in which iodine is oriented as described above, and a polarizing film stretched in a two-stage stretching process consisting of air-assisted stretching and boric acid-water stretching, can do. Further, the polarizing film used in the optical laminate of the present invention is made of a polyvinyl alcohol resin in which iodine is oriented as described above, and excessively dyes the laminate of the stretched PVA resin layer and the stretching resin substrate. And it can be set as the polarizing film produced by decoloring after that.

  The thickness of the polarizing film used for the optical layered body of the present invention is 12 μm or less, preferably 9 μm or less, more preferably 6 μm or less, and further preferably 5 μm or less.

<Phase difference film>
As the retardation film used in the optical layered body of the present invention, one obtained by stretching a polymer film or one obtained by aligning and fixing a liquid crystal material can be used. In this specification, the retardation film refers to a film having birefringence in the plane and / or in the thickness direction.

  Examples of the retardation film include an anti-reflection retardation film (see JP 2012-133303 [0221], [0222] [0228]) and a viewing angle compensation retardation film (JP 2012-133303 [0225]). , [0226]), and a tilted alignment phase difference film for viewing angle compensation (see JP 2012-133303 A [0227]).

  The retardation film is not particularly limited as long as it has substantially the above-mentioned function. For example, the retardation value, the arrangement angle, the three-dimensional birefringence, and whether it is a single layer or a multilayer are not particularly limited. Can be used.

  In this specification, Re [550] refers to an in-plane retardation value measured with light having a wavelength of 550 nm at 23 ° C. Re [550] is expressed by the formula: Re when the refractive index in the slow axis direction and the fast axis direction of the retardation film at a wavelength of 550 nm is nx and ny, respectively, and d (nm) is the thickness of the retardation film. [550] = (nx−ny) × d. The slow axis means the direction in which the in-plane refractive index is maximum.

  The in-plane birefringence Δn which is nx-ny of the present invention is 0.002 to 0.2, preferably 0.0025 to 0.15.

  The retardation film preferably has an in-plane retardation value (Re [550]) measured with light having a wavelength of 550 nm and an in-plane retardation value (Re [450] measured with light having a wavelength of 450 nm at 23 ° C. ]). In the retardation film having such a wavelength dispersion characteristic, when the ratio is within this range, the longer the wavelength, the more the phase difference appears, and an ideal retardation characteristic can be obtained at each wavelength in the visible region. For example, when used in an organic EL display, a retardation film having such wavelength dependency as a quarter wavelength plate is prepared, and a circularly polarizing plate or the like can be prepared by bonding with a polarizing plate, It is possible to realize a neutral polarizing plate and a display device with less hue wavelength dependency. On the other hand, when the ratio is out of this range, the wavelength dependency of the reflected hue becomes large, and coloring problems occur in the polarizing plate and the display device.

  The ratio of Re [550] to Re [450] (Re [450] / Re [550]) of the retardation film is 0.8 or more and less than 1.0, more preferably 0.8 to 0.95. .

  The retardation film preferably has an in-plane retardation value (Re [550]) measured with light having a wavelength of 550 nm and an in-plane retardation value (Re [650] measured with light having a wavelength of 650 nm at 23 ° C. ]) Smaller than. A retardation film having such a wavelength dispersion characteristic has a constant retardation value in a red region. For example, when used in a liquid crystal display device, a phenomenon in which light leaks depending on a viewing angle or a display image is red. It is possible to improve a taste-taking phenomenon (also referred to as a red-ish phenomenon).

  The ratio of Re [650] to Re [550] (Re [550] / Re [650]) of the retardation film is 0.8 or more and less than 1.0, preferably 0.8 to 097. By setting Re [550] / Re [650] in the above range, for example, when the retardation film is used in an organic EL display, even better display characteristics can be obtained.

  Re [450], Re [550], and Re [650] can be measured using the product name “AxoScan” manufactured by Axometrics.

  In the present specification, NZ refers to the ratio of nx-nz, which is birefringence in the thickness direction, and nx-ny, which is in-plane birefringence (also referred to as Nz coefficient).

  NZ of the retardation film of the present invention is 0 to 1.3, preferably 0 to 1.25, more preferably 0 to 1.2.

  The refractive index anisotropy of the retardation film of the present invention preferably satisfies the relationship of nx> ny, preferably nx> ny ≧ nz.

  For example, when normal longitudinal stretching is performed, width shrinkage occurs because the width direction is not fixed with respect to stretching in the longitudinal direction of the film. For this reason, molecules are more aligned in a uniaxial direction, and the refractive index relationship is, for example, nx> ny = nz. In this case, the folding strength in the longitudinal direction of the film, which is the stretching direction, becomes strong, but the folding strength in the width direction becomes very weak. In order to solve this, a state in which a force for regulating the width is generated in an angular direction intersecting the stretching direction (for example, in the case of lateral uniaxial stretching, in a direction perpendicular to the width direction of the film which is the stretching direction) By applying stretching, the molecules can be oriented not only in the stretching direction but also in the angular direction intersecting with the stretching direction. The refractive index relationship can be nx> ny> nz. Thus, the folding strength in the stretching direction and the folding strength in the width direction can be compatible at a high level.

The absolute value of the photoelastic coefficient at 23 ° C. of the retardation film; C (m ² / N) is 2 × 10 ^{−12 to} 100 × 10 ⁻¹² (m ² / N), preferably 2 × 10 ⁻¹² to 50 × 10 ⁻¹² (m ² / N). Due to the shrinkage stress of the polarizing film, the heat of the display panel, and the surrounding environment (moisture resistance / heat resistance), the retardation film is forcefully applied, and the resulting change in retardation value can be prevented. A display panel device having excellent display uniformity can be obtained. Preferably, C of the retardation film is 3 × 10 ^{−12 to} 45 × 10 ⁻¹² , particularly preferably 10 × 10 ⁻¹² to 40 × 10 ⁻¹² or less. By setting C in the above range, it is possible to reduce a change or unevenness in the retardation value that occurs when a force is applied to the retardation film. In addition, the photoelastic coefficient and Δn tend to be in a trade-off relationship, and within this photoelastic coefficient range, it is possible to maintain display quality without reducing the phase difference expression.

  In one embodiment, the retardation film of the present invention is produced by orienting a polymer film by stretching.

  As a method for stretching the polymer film, any suitable stretching method can be adopted depending on the purpose. Examples of the stretching method suitable for the present invention include a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, and a longitudinal and transverse sequential biaxial stretching method. As a means for stretching, any suitable stretching machine such as a tenter stretching machine or a biaxial stretching machine can be used. Preferably, the stretching machine includes a temperature control unit. When extending | stretching by heating, the internal temperature of a extending | stretching machine may be changed continuously and may be changed continuously. The process may be divided once or twice or more. The stretching direction is preferably stretched in the film width direction (TD direction) or in an oblique direction.

  In the oblique stretching, an unstretched resin film is sent out in the longitudinal direction, and an oblique stretching process of stretching in a direction that forms an angle in the specific range with respect to the width direction is continuously performed. Thereby, it is possible to obtain a long retardation film in which the angle (orientation angle θ) formed by the width direction of the film and the slow axis falls within the specific range.

  As a method of obliquely stretching, the film is continuously stretched in a direction that forms an angle of the specific range with respect to the width direction of the unstretched resin film, and a slow axis is set in the specific range with respect to the width direction of the film. If it can form in the direction which makes an angle, it will not restrict | limit in particular. It is possible to adopt any appropriate method from the conventionally known stretching methods such as JP-A-2005-319660, JP-A-2007-30466, JP-A-2014-194482, JP-A-2014-199483, JP-A-2014-199483, and the like. it can.

  The temperature at which the unstretched resin film is stretched (stretching temperature) can be appropriately selected depending on the purpose. Preferably, the stretching is performed in the range of Tg−20 ° C. to Tg + 30 ° C. with respect to the glass transition temperature (Tg) of the polymer film. By selecting such conditions, the retardation value is likely to be uniform, and the film is less likely to be crystallized (white turbid). Specifically, the stretching temperature is 90 ° C to 210 ° C, more preferably 100 ° C to 200 ° C, and particularly preferably 100 ° C to 180 ° C. The glass transition temperature can be obtained by a DSC method according to JIS K 7121 (1987).

  Any appropriate means can be adopted as means for controlling the stretching temperature. Examples of the temperature control means include an air circulation type thermostatic oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, a roll heated for temperature adjustment, a heat pipe roll, a metal belt, and the like. .

  The ratio (stretch ratio) for stretching the unstretched resin film can be appropriately selected according to the purpose. The draw ratio is preferably more than 1 and 6 times or less, more preferably more than 1.5 times and 4 times or less.

  The feeding speed during stretching is not particularly limited, but is preferably 0.5 m / min to 30 m / min, more preferably 1 m / min to 20 m / min from the viewpoint of mechanical accuracy and stability. If it is said extending | stretching conditions, not only the target optical characteristic can be acquired, but the phase difference film excellent in optical uniformity can be obtained.

  Also. As another embodiment, using a polycycloolefin film or a polycarbonate film, the angle formed by the absorption axis of the polarizing plate and the slow axis of the half-wave plate is 15 °, and the absorption axis of the polarizing plate is 1 / A retardation film laminated with a single sheet of acrylic adhesive may be used so that the angle formed by the slow axis of the four-wavelength plate is 75 °.

  In another embodiment, the retardation film of the present invention may be a laminate of retardation layers prepared by aligning and fixing a liquid crystal material. Each retardation layer may be an alignment solidified layer of a liquid crystal compound. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be remarkably increased as compared with a non-liquid crystal material, and thus the thickness of the retardation layer for obtaining a desired in-plane retardation. Can be significantly reduced. As a result, it is possible to further reduce the thickness of the circularly polarizing plate (finally, an organic EL display device). In the present specification, the “alignment solidified layer” refers to a layer in which a liquid crystal compound is aligned in a predetermined direction in the layer and the alignment state is fixed. In the present embodiment, typically, rod-like liquid crystal compounds are aligned in a state where they are aligned in the slow axis direction of the retardation layer (homogeneous alignment). Examples of the liquid crystal compound include a liquid crystal compound (nematic liquid crystal) whose liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal compound may exhibit liquid crystallinity either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

  When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking the liquid crystal monomer. After aligning the liquid crystal monomers, for example, if the liquid crystal monomers are polymerized or cross-linked, the alignment state can be fixed thereby. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, in the formed retardation layer, for example, a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change specific to the liquid crystal compound does not occur. As a result, the retardation layer is an extremely stable retardation layer that is not affected by temperature changes.

  The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on the type. Specifically, the temperature range is preferably 40 ° C to 120 ° C, more preferably 50 ° C to 100 ° C, and most preferably 60 ° C to 90 ° C.

  Any appropriate liquid crystal monomer can be adopted as the liquid crystal monomer. For example, polymerizable mesogenic compounds described in JP-T-2002-533742 (WO00 / 37585), EP358208 (US52111877), EP66137 (US4388453), WO93 / 22397, EP02661712, DE195504224, DE44081171, and GB2280445 can be used. Specific examples of such a polymerizable mesogenic compound include, for example, the trade name LC242 from BASF, the trade name E7 from Merck, and the trade name LC-Silicon-CC3767 from Wacker-Chem. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

  The alignment solidified layer of the liquid crystal compound is subjected to an alignment treatment on the surface of a predetermined substrate, and a coating liquid containing the liquid crystal compound is applied to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, It can be formed by fixing the alignment state. In one embodiment, the substrate is any suitable resin film, and the alignment solidified layer formed on the substrate can be transferred to the surface of the polarizing film. At this time, the angle between the absorption axis of the polarizing film and the slow axis of the liquid crystal alignment solidified layer is set to 15 °. The retardation of the liquid crystal alignment solidified layer is λ / 2 (about 270 nm) for a wavelength of 550 nm. Further, as described above, a liquid crystal alignment solidified layer having a wavelength of λ / 4 (about 140 nm) with respect to a wavelength of 550 nm is formed on a transferable substrate, and 1 / of the laminate of a polarizing film and a half-wave plate The two-wavelength plate is laminated so that the angle formed by the absorption axis of the polarizing film and the slow axis of the quarter-wave plate is 75 °.

  Any appropriate alignment treatment can be adopted as the alignment treatment. Specifically, a mechanical alignment process, a physical alignment process, and a chemical alignment process are mentioned. Specific examples of the mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of the physical alignment process include a magnetic field alignment process and an electric field alignment process. Specific examples of the chemical alignment treatment include oblique vapor deposition and photo-alignment treatment. Arbitrary appropriate conditions may be employ | adopted for the process conditions of various orientation processes according to the objective.

  The alignment of the liquid crystal compound is performed by processing at a temperature showing a liquid crystal phase according to the type of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound takes a liquid crystal state, and the liquid crystal compound is oriented according to the orientation treatment direction of the substrate surface.

  In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or a crosslinking treatment.

  Specific examples of the liquid crystal compound and details of the method for forming the alignment solidified layer are described in JP-A No. 2006-163343. The description in this publication is incorporated herein by reference.

[Protective film]
For the protective film of the transparent resin material used in the optical laminate of the present invention, a cycloolefin resin such as a norbornene resin, an olefin resin such as polyethylene or polypropylene, a polyester resin, a (meth) acrylic resin, or the like may be used. it can.

  The thickness of the protective film used in the optical laminate of the present invention is 10 to 50 μm, preferably 15 to 45 μm, and a surface treatment layer such as an antiglare layer or an antireflection layer can be appropriately provided.

The permeation humidity of the protective film used in the optical layered body of the present invention is 200 g / m ² or less, preferably 170 g / m ² or less, more preferably 130 g / m ² or less, and particularly preferably 90 g / m ² or less.

[First stress relaxation layer]
The 1st stress relaxation layer used for the laminated body for organic EL display devices of this invention is arrange | positioned with respect to the said protective film on the opposite side to the said phase difference film.

  The pressure-sensitive adhesive layer constituting the first stress relaxation layer used in the laminate for an organic EL display device of the present invention includes an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a polyester-based pressure-sensitive adhesive layer. Examples thereof include a pressure-sensitive adhesive, a polyamide-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a fluorine-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, and a polyether-based pressure-sensitive adhesive. In addition, the adhesive which comprises the said adhesive layer is used individually or in combination of 2 or more types. An acrylic pressure-sensitive adhesive is preferably used in terms of transparency, workability, durability, and the like.

  The thickness of the pressure-sensitive adhesive layer constituting the first stress relaxation layer used in the laminate for an organic EL display device of the present invention is 10 to 250 μm, preferably 10 to 150 μm. May be.

  The total light transmittance (according to JIS K 7136) in the visible light wavelength region of the first stress relaxation layer used in the laminate for an organic EL display device of the present invention is preferably 85% or more, more preferably 90% or more. is there.

  The haze (according to JIS K 7136) of the first stress relaxation layer used in the laminate for an organic EL display device of the present invention is 3.0% or less, more preferably 2.0% or less.

  In addition, the said total light transmittance and the said haze can be measured using a haze meter (Murakami Color Research Laboratory make, brand name "HM-150"), for example.

  The storage elastic modulus (G ′) of the first stress relaxation layer used in the laminate for an organic EL display device of the present invention is 0.05 to 0.15 (MPa) at 25 ° C.

[Transparent conductive layer]
For the transparent conductive layer of the present invention, a conductive nanowire or a metal mesh can be used. When a conductive nanowire or a metal mesh is used as the transparent conductive layer, the transparent conductive layer is configured to be bendable because it is excellent in bending resistance and hardly loses its conductivity even when bent. The conductive nanowire may be protected by a protective film.

  The thickness of the transparent conductive layer of the present invention is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 3 μm, and further preferably 0.1 μm to 1 μm.

  The total light transmittance of the transparent conductive layer of the present invention is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. For example, if conductive nanowires are used, a transparent conductive layer having openings can be formed, and a transparent conductive layer having high light transmittance can be obtained.

The density of the transparent conductive layer of the present invention is preferably from ^{1.0g / cm 3 ~10.5g / cm 3} , more preferably from ^{1.3g / cm 3 ~3.0g / cm 3} .

  The surface resistance value of the transparent conductive layer of the present invention is preferably 0.1Ω / □ to 1000Ω / □, more preferably 0.5Ω / □ to 500Ω / □, and further preferably 1Ω / □ to 250Ω / □. □.

  Any appropriate conductive nanowire can be used as the conductive nanowire as long as the effects of the present invention can be obtained. The conductive nanowire refers to a conductive substance having a needle shape or a thread shape and a diameter of nanometer size. The conductive nanowire may be linear or curved. If a transparent conductive layer composed of conductive nanowires is used, a conductive film having excellent bending resistance can be obtained. In addition, if a transparent conductive layer composed of conductive nanowires is used, the conductive nanowires form gaps and form a mesh, thereby providing a good electrical conduction path even with a small amount of conductive nanowires. A conductive film that can be formed and has low electric resistance can be obtained. Furthermore, when the conductive wire has a mesh shape, an opening can be formed in the mesh space to obtain a conductive film having a high light transmittance. Examples of the conductive nanowire include metal nanowires made of metal, conductive nanowires including carbon nanotubes, and the like.

  The ratio between the thickness d and the length L of the conductive nanowire (aspect ratio: L / d) is preferably 10 to 100,000, more preferably 50 to 100,000, and particularly preferably 100. -10,000. When conductive nanowires having a large aspect ratio are used in this way, the conductive nanowires can cross well and high conductivity can be expressed by a small amount of conductive nanowires. As a result, a conductive film having a high light transmittance can be obtained. In this specification, “the thickness of the conductive nanowire” means the diameter when the cross section of the conductive nanowire is circular, and the short diameter when the cross section of the conductive nanowire is elliptical. If it is square, it means the longest diagonal. The thickness and length of the conductive nanowire can be confirmed by a scanning electron microscope or a transmission electron microscope.

  The thickness of the conductive nanowire is preferably less than 500 nm, more preferably less than 200 nm, particularly preferably 1 nm to 100 nm, and most preferably 1 nm to 50 nm. If it is such a range, a transparent conductive layer with high light transmittance can be formed.

  The length of the conductive nanowire is preferably 2.5 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 20 μm to 100 μm. If it is such a range, a highly conductive conductive film can be obtained.

  Any appropriate metal can be used as the metal constituting the metal nanowire as long as it is a highly conductive metal. The metal nanowire is preferably composed of one or more metals selected from the group consisting of gold, platinum, silver and copper. Among these, silver, copper, or gold is preferable from the viewpoint of conductivity, and silver is more preferable. Alternatively, a material obtained by performing a plating process (for example, a gold plating process) on the metal may be used.

  Any appropriate method can be adopted as a method for producing the metal nanowire. For example, a method of reducing silver nitrate in a solution, a method in which an applied voltage or current is applied to the precursor surface from the tip of the probe, a metal nanowire is drawn out at the probe tip, and the metal nanowire is continuously formed, etc. . In the method of reducing silver nitrate in a solution, silver nanowires can be synthesized by liquid phase reduction of a silver salt such as silver nitrate in the presence of a polyol such as ethylene glycol and polyvinylpyrrolidone. Uniformly sized silver nanowires are described in, for example, Xia, Y. et al. etal. Chem. Mater. (2002), 14, 4736-4745, Xia, Y. et al. etal. , Nano letters (2003) 3 (7), 955-960, mass production is possible.

  Any appropriate carbon nanotube may be used as the carbon nanotube. For example, so-called multi-walled carbon nanotubes, double-walled carbon nanotubes, single-walled carbon nanotubes and the like are used. Among these, single-walled carbon nanotubes are preferably used because of their high conductivity. Any appropriate method can be adopted as a method for producing the carbon nanotube. Preferably, carbon nanotubes produced by an arc discharge method are used. Carbon nanotubes produced by the arc discharge method are preferred because of their excellent crystallinity.

  The transparent conductive layer containing the conductive nanowire is obtained by applying a dispersion liquid (conductive nanowire dispersion liquid) obtained by dispersing the conductive nanowire in a solvent onto the retardation film, and then drying the coating layer. Can be formed.

  Examples of the solvent contained in the conductive nanowire dispersion include water, alcohol solvents, ketone solvents, ether solvents, hydrocarbon solvents, aromatic solvents, and the like. From the viewpoint of reducing the environmental load, it is preferable to use water.

  The dispersion concentration of the conductive nanowires in the conductive nanowire dispersion liquid is preferably 0.1% by weight to 1% by weight. If it is such a range, the transparent conductive layer excellent in electroconductivity and light transmittance can be formed.

  The conductive nanowire dispersion may further contain any appropriate additive depending on the purpose. Examples of the additive include a corrosion inhibitor for preventing corrosion of the conductive nanowire, and a surfactant for preventing aggregation of the conductive nanowire. The type, number and amount of additives used can be appropriately set according to the purpose. In addition, the conductive nanowire dispersion liquid may contain any appropriate binder resin as necessary as long as the effects of the present invention are obtained.

  Any appropriate method can be adopted as a method of applying the conductive nanowire dispersion. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, slot die coating, letterpress printing method, intaglio printing method, and gravure printing method. Any appropriate drying method (for example, natural drying, air drying, heat drying) can be adopted as a method for drying the coating layer. For example, in the case of heat drying, the drying temperature is typically 100 ° C. to 200 ° C., and the drying time is typically 1 minute to 10 minutes.

  When the said transparent conductive layer is comprised from electroconductive nanowire, the thickness of this transparent conductive layer becomes like this. Preferably it is 0.01 micrometer-10 micrometers, More preferably, it is 0.05 micrometer-3 micrometers, More preferably, it is 0.1 micrometer- 1 μm. If it is such a range, the electroconductive film which is excellent in electroconductivity and light transmittance can be obtained.

  When the transparent conductive layer is composed of conductive nanowires, the total light transmittance of the transparent conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. .

  When the conductive nanowire is a metal nanowire made of silver, the density of the transparent conductive layer is preferably 1.0 g / cm3 to 10.5 g / cm3, more preferably 1.3 g / cm3 to 3. 0 g / cm 3. If it is such a range, the electroconductive film which is excellent in electroconductivity and light transmittance can be obtained.

  The transparent conductive layer including the conductive nanowire can be patterned into a predetermined pattern. The pattern of the transparent conductive layer is preferably a pattern that operates well as a touch panel (for example, a capacitive touch panel). For example, JP 2011-511357 A, JP 2010-164938 A, and JP 2008-310550 A. And the patterns described in Japanese Patent Publication No. 2003-511799 and Japanese Patent Publication No. 2010-541109. After the transparent conductive layer is formed on the transparent substrate, it can be patterned using a known method.

  As the metal mesh, any appropriate metal mesh can be used as long as the effects of the present invention are obtained. For example, it is possible to use a metal wiring layer provided on a film substrate that is patterned in a mesh pattern.

(Film substrate)
The film substrate that supports the metal wiring layer may be a single layer or multiple layers. The thickness of the film substrate is preferably 20 μm to 200 μm from the viewpoint of transparency and handleability.

  The film substrate has a plurality of protrusions on both sides on which the metal wiring layer is formed. By providing a plurality of protrusions on the surface of the film base material, the film base material is provided with slipperiness and abrasion resistance, and when the metal wiring layer is continuously formed, the quality is kept high while maintaining the quality. Productivity can be improved by increasing the deposition rate.

  The protrusion has an outer diameter D exceeding 0 and not more than 3 μm, preferably 0.1 μm to 2 μm, in a plan view of the surface of the film base on which the metal wiring layer is formed. The outer diameter of the protrusion can be measured, for example, by observing an image of the surface of the film base on which the metal wiring layer is formed at a predetermined magnification. When the outer diameter D is 3 μm or less, it is possible to reliably prevent the metal wiring from being disconnected near the boundary between the surface of the film base and the surface of the protrusion.

  The height of the protrusion is preferably more than 0 and 3 μm or less, more preferably 0.1 μm to 2 μm, based on the flat surface of the film substrate.

In this embodiment, the shape of the protrusion is substantially a dome shape, and the cross section in the surface direction of the film base is substantially circular and the cross section in the thickness direction is substantially semicircular. However, the protrusion in the present invention is not a dome shape as long as it imparts slipperiness and wear resistance to the film substrate and can form a high-quality metal wiring layer continuously and at a high speed. Other shapes may be used.

  Examples of means for providing protrusions on the film substrate include a method in which a lubricant is dispersed inside the film substrate, and a method in which a binder in which a plurality of particles are dispersed is applied to the film surface.

  The film constituting the film substrate is preferably a polymer film having optical isotropy. In the present invention, “optically isotropic” means that the in-plane retardation value measured at a wavelength of 590 nm is less than 10 nm. If such a polymer film is used, when external light is incident on the touch sensor, the change in the phase of the light between the two metal wiring layers is small. It can be effectively blocked. This polymer film is, for example, an unstretched film that has not been stretched.

  The polymer film is, for example, a polycycloolefin film or a polycarbonate film. This polymer film can be obtained from, for example, Nippon Zeon Co., Ltd., Teijin Chemicals Ltd. and the like.

(Metal wiring layer)
The metal wiring layer is formed in a pattern, for example, in a mesh shape to impart translucency. The mesh pattern of the metal wiring layer is not particularly limited, and is, for example, a square lattice, a rhombus lattice, or a polygonal lattice.

Although the material which forms the said metal wiring layer will not be restrict | limited if it has electrical conductivity, Preferably it is silver, copper, or those alloys, More preferably, it is copper.

  The line width of the metal wiring layer is more than 5 μm and less than 8 μm, preferably more than 5.5 μm and 7 μm or less. If it is the range of such a line | wire width, the disconnection resulting from the protrusion of a film base material can be prevented. When the line width is 5 μm or less, the network pattern of the metal wiring layer becomes difficult to be visually recognized, but the frequency of the metal wiring breaks due to the protrusions of the film base, and the quality and reliability are high when mass-produced. Lower. On the other hand, when the line width is 8 μm or more, the mesh pattern of the metal wiring layer is remarkably visually recognized.

  The thickness of the metal wiring layer is 0.1 μm or more and less than 0.5 μm, preferably more than 0.1 μm and 0.4 μm or less, and more preferably 0.15 μm to 0.35 μm. By reducing the thickness of the metal wiring layer to, for example, less than 2 μm, the mesh pattern is further prevented from being visually recognized. In such a configuration, when external light is incident on the touch sensor from an oblique direction, the side surface of the metal wiring layer does not shine and is difficult to be visually recognized.

  The metal wiring layer is characterized in that it has a flat shape, and the ratio of the line width to the thickness (line width / thickness) is preferably 10 or more and less than 80, and more preferably 15-50. A touch sensor satisfying such a relationship is excellent in productivity, does not cause disconnection of the metal wiring, and is difficult to visually recognize the mesh pattern of the metal wiring layer.

Sectional area of the metal wiring layer, in order to obtain the electrical conductivity required for a touch panel sensor, preferably 0.5μm ² ~4μm ^2, more preferably from 0.5μm ² ~3.2μm ^2, particularly preferably is a 0.5μm ² ~2.5μm ^2.

  The pitch interval of the metal wiring layers is preferably 200 μm to 800 μm, and more preferably 350 μm to 650 μm, in order to obtain sufficient translucency. The aperture ratio of the metal wiring layer is preferably 95% to 99%, more preferably 96% to 99%.

  As a method of forming the metal wiring layer, for example, after forming a metal layer on the entire surface of the film substrate, a predetermined resist pattern (resist pattern) is laminated on the metal layer, and etching is performed. A method of removing the resist after removing the metal layer in the unnecessary region is used so that a network-like metal wiring layer is formed. The metal layer can be formed by, for example, a sputtering method, a plating method, or a combination thereof.

  The transparent conductive layer of the present invention constitutes a touch sensor and is configured to be bendable.

  The transparent conductive layer of the present invention may be disposed on the side opposite to the protective film with respect to the retardation film.

  The transparent conductive layer of the present invention can be disposed between the protective film and the first stress relaxation layer.

[Second stress relaxation layer]
When the transparent conductive layer is disposed on the opposite side of the protective film with respect to the retardation film, the second stress relaxation layer used in the laminate for an organic EL display device of the present invention is And disposed on the opposite side of the retardation film.

  When the transparent conductive layer is disposed between the protective film and the first stress relaxation layer, the second stress relaxation layer used in the laminate for an organic EL display device according to the present invention is And disposed on the opposite side of the protective film.

[Organic EL display device]
The organic EL display device of the present invention includes the above-described laminate for an organic EL display device and an organic EL display panel configured to be bendable, and the organic EL display device laminate on the viewing side with respect to the organic EL display panel. The body is arranged and configured to be bendable.

  Although it is arbitrary, a window can be arrange | positioned at the visual recognition side with respect to the laminated body for organic electroluminescent display apparatuses.

  FIG. 2 is a cross-sectional view showing one embodiment of the organic EL display device according to the present invention. The organic EL display device 100 includes an organic EL display device laminate 110 and an organic EL display panel 101 configured to be bendable. And the laminated body 110 for organic EL display apparatuses is arrange | positioned at the visual recognition side with respect to the organic EL display panel 101, and the organic EL display apparatus 100 is comprised so that bending is possible.

  Although it is optional, a transparent window 102 can be disposed on the viewing side with respect to the organic EL display device laminate 110.

  The organic EL display device laminate 110 includes an optical laminate 120 and a pressure-sensitive adhesive layer that constitutes the first stress relaxation layer 111.

  The optical laminate 120 includes a polarizing film 121, a protective film 122 made of a transparent resin material, and a retardation film 123. The protective film 122 made of a transparent resin material is bonded to the first surface on the viewing side of the polarizing film 121. The retardation film 123 is bonded to a second surface different from the first surface of the polarizing film 121. The polarizing film 121 and the retardation film 123 generate, for example, circularly polarized light to prevent light incident on the inside from the viewing side of the polarizing film 121 from being internally reflected and emitted to the viewing side. It is for compensating.

  In the present embodiment, the protective film is provided on both surfaces of the conventional polarizing film, whereas the protective film is provided only on one surface, and the polarizing film itself is also used in the conventional organic EL display device. The thickness of the optical laminated body 120 is reduced by using a polarizing film having a very thin thickness of 12 μm or less compared to the polarizing film. Further, since the polarizing film 121 is very thin compared to the polarizing film used in the conventional organic EL display device, the stress due to expansion and contraction generated under temperature or humidity conditions is extremely small. Therefore, the possibility that the stress generated by the contraction of the polarizing film causes warpage or other deformation in the adjacent organic EL display panel 101 is greatly reduced, and the deterioration in display quality and the destruction of the panel sealing material due to the deformation are greatly reduced. Can be suppressed.

  The storage elastic modulus at 25 ° C. of the first stress relaxation layer 111 is 0.05 to 0.15 MPa, and is disposed on the opposite side of the retardation film 123 with respect to the protective film 122.

  When the optical laminate 120 is bent with the protective film 122 side inside, the thickness of the optical laminate 120 is reduced to 120 μm or less, and the first stress relaxation layer 111 having the above storage elastic modulus is formed on the protective film 122. On the other hand, the stress applied to the optical laminated body 120 can be reduced by disposing the optical laminated body 120 on the side opposite to the retardation film 123, whereby the optical laminated body 120 can be bent. Accordingly, an appropriate storage elastic modulus range may be set according to the environmental temperature in which the organic EL display device is used. For example, when the assumed use environment temperature is 0 ° C. to 80 ° C., the first stress relaxation layer can be used such that the storage elastic modulus at 0 ° C. and the storage elastic modulus at 80 ° C. are in an appropriate numerical range.

  Although optional, a foldable transparent conductive layer 112 constituting a touch sensor may be further disposed on the opposite side of the retardation film 123 from the protective film 122. The transparent conductive layer 112 is configured to be directly bonded to the retardation film 123 by a manufacturing method as disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-219667, whereby the thickness of the optical laminate 120 is reduced, and the optical laminate 120 It is possible to further reduce the stress applied to the optical layered body 120 when it is bent.

  Although it is optional, a pressure-sensitive adhesive layer constituting the second stress relaxation layer 113 may be further disposed on the opposite side of the transparent conductive layer 112 from the retardation film 123. In the present embodiment, the second stress relaxation layer 113 is directly bonded to the transparent conductive layer 112. By providing the second stress relaxation layer 113, the stress applied to the optical laminate 120 when the optical laminate 120 is bent can be further reduced.

  The organic EL display device shown in FIG. 3 is basically the same as that shown in FIG. 2, but the transparent conductive layer 112 is not directly joined to the retardation film 123, and an optical device such as a polycycloolefin or a polycarbonate film is used. In particular, the transparent conductive layer 112 provided on the film substrate 114 having isotropic properties is different from the retardation film 123 in that the transparent conductive layer 112 is bonded to the retardation film 123.

  The organic EL display device shown in FIG. 4 is almost the same as that shown in FIG. 2, but in the organic EL display device of FIG. 2, a touch sensor is provided on the opposite side of the retardation film 123 from the protective film 122. 4 is disposed, whereas in the organic EL display device of FIG. 4, a touch sensor is formed between the protective film 122 and the first stress relaxation layer 123. The difference is that a foldable transparent conductive layer 112 is disposed. In the organic EL display device of FIG. 2, the second stress relaxation layer 113 is disposed on the opposite side of the retardation film 123 with respect to the transparent conductive layer 112, whereas the organic EL display of FIG. The display device is different in that it is disposed on the side opposite to the protective film 122 with respect to the retardation film 123.

  The optical layered body of the present invention will be further described using the following examples. In addition, the optical laminated body of this invention is not limited only to these Examples.

[Example 1]
[Polarizing film]
As a thermoplastic resin substrate, an amorphous polyethylene terephthalate (hereinafter also referred to as “PET”) (IPA copolymerized PET) film (thickness: 100 μm) having 7 mol% of isophthalic acid units is prepared, and the surface is corona-treated ( 58 W / m ² / min). On the other hand, 1 wt. Of acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%)) % PVA (polymerization degree 4200, saponification degree 99.2%) is prepared, and a coating solution of PVA aqueous solution with 5.5% by weight of PVA resin is prepared, and the film thickness after drying is 12 μm. This was coated and dried for 10 minutes by hot air drying in an atmosphere of 60 ° C. to prepare a laminate in which a PVA resin layer was provided on the substrate.

  Next, this laminate was first stretched 1.8 times in air at 130 ° C. (air-assisted stretching) to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid insolubilized aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water. A colored laminate was produced by dyeing this stretched laminate. In the colored laminate, the stretched laminate is dyed into a dye solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. so that the single transmittance of the PVA layer constituting the finally produced polarizing film is 40 to 44%. The PVA layer contained in the stretched laminate is dyed with iodine by immersing it in an arbitrary time. In this step, the staining solution was prepared using water as a solvent, an iodine concentration in the range of 0.1 to 0.4% by weight, and a potassium iodide concentration in the range of 0.7 to 2.8% by weight. The concentration ratio of iodine and potassium iodide is 1 to 7. Next, the colored laminated body was immersed in a 30 ° C. boric acid crosslinking aqueous solution for 60 seconds to perform a crosslinking treatment between PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid crosslinking aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water.

  Furthermore, the obtained colored laminate was stretched in a boric acid aqueous solution at a stretching temperature of 70 ° C. and stretched 3.05 times in the same direction as the stretching in the air (boric acid-water stretching), and finally An optical film laminate having a draw ratio of 5.50 was obtained. The optical film laminate was removed from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution having a potassium iodide content of 4 parts by weight with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. The thickness of the polarizing film contained in the obtained optical film laminate was 5 μm.

[Retardation film]
Polymerization was carried out using a batch polymerization apparatus comprising two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. 9,9- [4- (2-hydroxyethoxy) phenyl] fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenyl carbonate (DPC), and magnesium acetate tetrahydrate in a molar ratio of BHEPF / ISB / DEG / DPC / magnesium acetate = 0.348 / 0.490 / 0.162 / 1.005 / 1.00 × 10 ⁻⁵ . After sufficiently replacing the inside of the reactor with nitrogen (oxygen concentration 0.0005 to 0.001 vol%), heating was performed with a heating medium, and stirring was started when the internal temperature reached 100 ° C. After 40 minutes from the start of temperature increase, the internal temperature was reached to 220 ° C., and control was performed so as to maintain this temperature. The phenol vapor produced as a by-product with the polymerization reaction was led to a reflux condenser at 100 ° C., and a monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the phenol vapor not condensed was led to a condenser at 45 ° C. and recovered.

  Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Subsequently, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240 ° C. and the pressure was 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was obtained. When a predetermined power is reached, nitrogen is introduced into the reactor, the pressure is restored, the reaction solution is withdrawn in the form of a strand, pelletized with a rotary cutter, and BHEPF / ISB / DEG = 34.8 / 49.0 / A polycarbonate resin A having a copolymer composition of 16.2 [mol%] was obtained. This polycarbonate resin had a reduced viscosity of 0.430 dL / g and a glass transition temperature of 128 ° C.

  The obtained polycarbonate resin was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T-die (width 900 mm, set temperature: 220). ° C.), a chill roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winder, a 150 μm thick polycarbonate resin film was produced.

  The polycarbonate resin film obtained as described above was subjected to pre-heat treatment, first oblique stretching, and second oblique stretching treatment to obtain a long retardation film. Specifically, it is as follows.

  Referring to FIG. 5, a polycarbonate resin film (thickness 150 μm, width (W1) 765 mm) was conveyed while being held by left and right clips 1 (gripping zone A), and preheated to 145 ° C. in preheating zone B of the stretching apparatus. . In the preheating zone B, the clip pitch (P1) of the left and right clips was 125 mm. Next, at the same time as the film entered the first oblique stretching zone C, it started to increase the clip pitch of the right clip and decrease the clip pitch of the left clip. The rate of change of the clip pitch (P2 / P1) of the right clip at the end of the first oblique stretching zone C is 1.42, and the rate of change of the clip pitch of the left clip (P3 / P1) is 0.72. It was. The first oblique stretching was performed at 138 ° C. The film width (W2) after the first oblique stretching was 1092 mm (TD stretching ratio (W2 / W1) = 1.45 times). Next, as soon as the film entered the second oblique stretching zone D, the clip pitch of the left clip started to increase and increased from P3 to P2. The rate of change (P2 / P3) of the clip pitch of the left clip in the second oblique stretching zone D was 1.97. On the other hand, the clip pitch of the right clip was maintained at P2 in the second oblique stretching zone D. The second oblique stretching was performed at 138 ° C. The film width (W3) after the second oblique stretching was 1419 mm. Moreover, the draw ratio (W3 / W1) in the width direction in the first oblique stretching step and the second oblique stretching step was 1.9 times.

  Next, in the release zone, the film was held at 125 ° C. for 60 seconds for heat setting. After the heat-set film was cooled to 100 ° C., the left and right clips were opened (open zone E).

  As described above, a long retardation film (thickness 55 μm, width 1419 mm) having an orientation angle of 48 ° was obtained.

[First stress relaxation layer]
The pressure-sensitive adhesive layer constituting the first stress relaxation layer of this example was produced by the following method.
Butyl acrylate (BA): 67 parts by weight, cyclohexyl acrylate (CHA): 14 parts by weight, 4-hydroxybutyl acrylate (4HBA): 27 parts by weight, hydroxyethyl acrylate (HEA): 9 parts by weight, 2,2-dimethoxy- 1,2-diphenyl-1-one (trade name “Irgacure 651”, manufactured by BASF Japan): 0.05 parts by weight, and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name “Irgacure 184”, BASF Japan) Manufactured): 0.05 part by weight was charged into a four-necked flask and exposed to ultraviolet light under a nitrogen atmosphere to partially photopolymerize to obtain a partially polymerized product (monomer syrup) having a polymerization rate of 10%. . To 100 parts by weight of this partially polymerized product, 0.1 parts by weight of an isocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd., solid content: 75% by weight) in terms of solid content was added and then mixed uniformly. Thus, a photopolymerizable composition was prepared.

  This photopolymerizable composition is applied on a release treatment surface of a release liner (type on which one side of a polyethylene terephthalate film has been subjected to a release treatment, thickness 38 μm, trade name “MRF38”, manufactured by Mitsubishi Plastics). After forming the layer, a similar release liner was provided on the coating layer.

Next, an ultraviolet ray having an intensity of 5 mW / cm ² is irradiated with black light, polymerization is performed until the light intensity is irradiated to 3600 mJ / cm ² , and an adhesive sheet (base material) provided with separators on both sides of the adhesive layer Less type, pressure-sensitive adhesive layer thickness: 100 μm).

  The weight average molecular weight of the acrylic polymer as the base polymer of the pressure-sensitive adhesive layer was 2 million.

[Optical laminate]
The long retardation film having the slow axis in the oblique direction obtained as described above and the long polarizing film having the absorption axis in the longitudinal direction obtained as described above are continuously used using a roll-to-roll method. Thus, a long laminated film was produced so that the axis angle of the slow axis and the absorption axis was 45 °.

  Subsequently, the circular film was produced by cutting the obtained long film into 15 cm × 1 cm.

  A (meth) acrylic resin film serving as a protective film was bonded to the obtained circularly polarizing plate via an adhesive to prepare an optical laminate. Further, the separator is peeled off from the pressure-sensitive adhesive sheet obtained as described above, and the pressure-sensitive adhesive constituting the first stress relaxation layer is bonded to the (meth) acrylic resin film serving as a protective film, thereby providing an organic EL display device. A laminate was prepared. If this pressure-sensitive adhesive layer is exposed, it will be difficult to perform a 180 ° folding resistance test, which will be described later. Therefore, PET having a thickness of 38 μm is formed on the pressure-sensitive adhesive layer of the laminate for an organic EL display device. The substrate was bonded.

  Various evaluation was performed as follows about the obtained polarizing film, retardation film, an optical laminated body, the adhesive layer which comprises a 1st stress relaxation layer, and the laminated body for organic electroluminescence displays. Table 1 shows properties of the obtained polarizing film, retardation film, optical laminate, pressure-sensitive adhesive layer constituting the first stress relaxation layer, and organic EL display laminate.

[Example 2]
Except for the following differences, a polarizing film, a pressure-sensitive adhesive layer constituting the first stress relaxation layer, and a laminate for an organic EL display device were produced and produced under the same conditions as in Example 1, and various evaluations were performed as follows. Went. The difference is in the configuration of the retardation film. The retardation film of Example 1 was a single-layer retardation film manufactured by an oblique stretching method. However, the retardation film (¼ wavelength retardation plate 6) of this example is aligned with a liquid crystal material. The retardation film is composed of two layers, ie, the fixed retardation layer 8 for quarter-wave plate and the retardation layer 9 for half-wave plate. Specifically, it was manufactured as follows.
(Liquid crystal material)
As materials for forming the retardation layer 9 for half-wave plates and the retardation layer 8 for quarter-wave plates, a polymerizable liquid crystal material exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Palicolor LC 2 4 2) Was used. A photopolymerization initiator (manufactured by BASF: trade name Irgacure 9 07) for the polymerizable liquid crystal material was dissolved in toluene. Further, for the purpose of improving the coatability, a DIC MegaFac series was added in an amount of about 0.1 to 0.5% depending on the thickness of the liquid crystal to prepare a liquid crystal coating solution. The liquid crystal coating liquid was applied onto the alignment substrate with a bar coater, then heated and dried at 90 ° C. for 2 minutes, and then alignment fixed by ultraviolet curing in a nitrogen atmosphere. As the substrate, for example, a material that can transfer the liquid crystal coating layer later, such as PET, was used. Furthermore, in order to improve coatability, DIC's MegaFac series fluoropolymer is added in an amount of 0.1% to 0.5% depending on the thickness of the liquid crystal layer, and MIBK (methyl isobutyl ketone), cyclohexanone, or MIBK is added. Using a mixed solvent of cyclohexanone and a solid content concentration of 25%, a coating solution was prepared. This coating solution was applied to a substrate with a wire bar to obtain a drying process for 3 minutes at a setting of 65 ° C., and prepared by orientation fixing by ultraviolet curing in a nitrogen atmosphere. As the substrate, for example, a material that can transfer the liquid crystal coating layer later, such as PET, was used.

(Manufacturing process)
With reference to FIG. 6, the manufacturing process of a present Example is demonstrated. In the manufacturing process 20, the base material 14 is provided by a roll, and the base material 14 is supplied from a supply reel 21. In the manufacturing process 20, the coating solution of the ultraviolet curable resin 10 was applied to the base material 14 by the die 22. In this manufacturing process 20, the roll plate 30 is a cylindrical mold for molding in which the concavo-convex shape of the quarter-wave plate alignment film 11 of the quarter-wave retardation plate 6 is formed on the peripheral side surface. It was. In the manufacturing process 20, the base material 14 coated with the ultraviolet curable resin is pressed against the peripheral side surface of the roll plate 30 by the pressure roller 24, and the ultraviolet curable resin is obtained by irradiating the ultraviolet ray with the ultraviolet irradiation device 25 made of a high-pressure mercury lamp. Cured. Thereby, the manufacturing process 20 transferred the uneven | corrugated shape formed in the surrounding side surface of the roll plate 30 to the base material 14 so that it might become 75 degrees with respect to MD direction. Thereafter, the base material 14 was peeled from the roll plate 30 integrally with the ultraviolet curable resin 10 cured by the peeling roller 26, and a liquid crystal material was applied by the die 29. Thereafter, the liquid crystal material was cured by irradiating with ultraviolet rays from the ultraviolet irradiating device 27, thereby forming a configuration related to the quarter-wave plate retardation layer 8. Subsequently, in this step 20, the base material 14 is transported to the die 32 by the transport roller 31, and the coating solution of the ultraviolet curable resin 12 is applied onto the quarter-wave plate retardation layer 8 of the base material 14 by the die 32. Applied. In this manufacturing process 20, the roll plate 40 is a cylindrical shaping mold in which the uneven shape related to the alignment film 13 for the half-wave plate of the quarter-wave retardation plate 6 is formed on the peripheral side surface. It was. In the manufacturing process 20, the base material 14 coated with the ultraviolet curable resin is pressed against the peripheral side surface of the roll plate 40 by the pressure roller 34, and the ultraviolet curable resin is applied by irradiating the ultraviolet rays with the ultraviolet irradiation device 35 made of a high-pressure mercury lamp. Cured. Thereby, the manufacturing process 20 transferred the uneven | corrugated shape formed in the surrounding side surface of the roll plate 40 to the base material 14 so that it might become 15 degrees with respect to MD direction. Thereafter, the base material 14 was peeled from the roll plate 40 integrally with the ultraviolet curable resin 12 cured by the peeling roller 36, and a liquid crystal material was applied by the die 39. Thereafter, the liquid crystal material was cured by irradiating with ultraviolet rays from the ultraviolet irradiating device 37, and the configuration related to the retardation layer 9 for half-wave plate was thereby created.

Various evaluation was performed as follows about the obtained polarizing film, retardation film, an optical laminated body, the adhesive layer which comprises a 1st stress relaxation layer, and the laminated body for organic electroluminescence displays.

  Table 1 shows properties of the obtained polarizing film, retardation film, optical laminate, pressure-sensitive adhesive layer constituting the first stress relaxation layer, and organic EL display laminate.

Example 3
A polarizing film, a retardation film, an optical film under the same conditions as in Example 1 except that an adhesive having a storage elastic modulus at 25 ° C. of 0.05 MPa is used as an adhesive for the adhesive layer constituting the first stress relaxation layer. A laminate and a laminate for an organic EL display device were produced and produced, and various evaluations were performed as follows.

  The pressure-sensitive adhesive layer constituting the first stress relaxation layer of this example was produced by the following method.

  By mixing 50 parts by weight of lauryl acrylate (LA), 32 parts by weight of 2-ethylhexyl acrylate (2EHA), 8 parts by weight of 4-hydroxybutyl acrylate (HBA) and 10 parts by weight of N-vinyl-2-pyrrolidone (NVP) A mixture (monomer mixture) was obtained. Next, 100 parts by weight of the above mixture, 0.05 part by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (trade name “Irgacure 184”, manufactured by BASF Japan Ltd., photopolymerization initiator) and 2,2-dimethoxy-1, 0.05 parts by weight of 2-diphenylethane-1-one (trade name “Irgacure 651”, manufactured by BASF Japan Ltd., photopolymerization initiator) was charged into a four-necked flask, and the viscosity (BH viscosity) under a nitrogen atmosphere. A partially polymerized monomer syrup (a partially polymerized monomer component) was obtained by irradiating ultraviolet rays until the system No. 5 rotor, 10 rpm, temperature 30 ° C.) was about 15 Pa · s, and photopolymerized.

  100 parts by weight of this partially polymerized monomer syrup, 0.04 parts by weight of 1,6-hexanediol diacrylate (HDDA, polyfunctional monomer), 1-hydroxy-cyclohexyl-phenyl-ketone (trade name “Irgacure 184”, BASF Japan Co., Ltd., photopolymerization initiator (addition initiator) 0.05 parts by weight and 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name “Irgacure 651”, manufactured by BASF Japan Ltd., A photopolymerization initiator (addition initiator)) 0.05 part by weight and a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 part by weight are uniformly mixed to obtain an adhesive. A composition was obtained. The pressure-sensitive adhesive composition was applied onto the release-treated surface of a release film (trade name “MRF # 38”, manufactured by Mitsubishi Plastics Co., Ltd.) so that the thickness after forming the pressure-sensitive adhesive layer was 100 μm. Then, an adhesive composition layer was formed, and then a release film (trade name “MRN # 38”, manufactured by Mitsubishi Plastics, Inc.) was bonded to the surface of the adhesive composition layer. Thereafter, an ultraviolet ray was irradiated under the conditions of illuminance: 4 mW / cm 2 and light amount: 1200 mJ / cm 2 to photocur the pressure-sensitive adhesive composition layer, and a pressure-sensitive adhesive sheet having a separator provided on both sides of the pressure-sensitive adhesive layer (base material-less Type, pressure-sensitive adhesive layer thickness: 100 μm).

  Table 1 shows properties of the obtained polarizing film, retardation film, optical laminate, pressure-sensitive adhesive layer constituting the first stress relaxation layer, and organic EL display laminate.

[Comparative Example 1]
[Polarizing film]
A polyvinyl alcohol film having a thickness of 50 μm is immersed in five baths of the following [1] to [5] through a plurality of sets of rolls having different peripheral speeds while sequentially applying tension in the longitudinal direction of the film. The original length was stretched to 6.0 times. This film was dried in an oven at 50 ° C. for 4 minutes to obtain a polarizing film having a thickness of 22 μm.
[1] Swelling bath: 30 ° C. pure water [2] Dyeing bath: The iodine concentration is in the range of 0.02 to 0.2% by weight and the potassium iodide concentration is 0.14 to 100 parts by weight of water. It was made into the range of 1.4 weight%. The concentration ratio of iodine and potassium iodide is 1 to 7. The film was immersed in a 30 ° C. aqueous solution containing these for an arbitrary period of time so that the final transmittance of the polarizing film was 40 to 44%.
[3] First crosslinking bath: 40 ° C. aqueous solution containing 3% by weight of potassium iodide and 3% by weight of boric acid.
[4] Second crosslinking bath: 60 ° C. aqueous solution containing 5% by weight of potassium iodide and 4% by weight of boric acid.
[5] Washing bath: 25 ° C. aqueous solution containing 3% by weight of potassium iodide

[Retardation film]
Isosorbide (hereinafter sometimes abbreviated as “ISB”) may be abbreviated as 445.1 parts by weight, 9,9- (4- (2-hydroxyethoxy) phenyl) fluorene (hereinafter, “BHEPF”). ) 906.2 parts by weight, molecular weight 1000 polyethylene glycol (hereinafter sometimes abbreviated as “PEG # 1000”) 15.4 parts by weight, diphenyl carbonate (hereinafter abbreviated as “DPC”) 1120.4 parts by weight and 6.27 parts by weight of cesium carbonate (0.2% by weight aqueous solution) as a catalyst, respectively, in the reactor, and the first step of the reaction in a nitrogen atmosphere As described above, the temperature of the heating medium in the reaction vessel was set to 150 ° C., and the raw materials were dissolved while stirring as necessary (about 15 minutes). Next, the pressure in the reaction vessel was changed from normal pressure to 13.3 kPa, and the generated phenol was extracted out of the reaction vessel while the temperature of the heat medium in the reaction vessel was increased to 190 ° C. over 1 hour.

  After holding the reaction vessel temperature at 190 ° C. for 15 minutes, as a second step, the pressure in the reaction vessel is set to 6.67 kPa, and the heat medium temperature of the reaction vessel is increased to 230 ° C. in 15 minutes. The generated phenol was extracted out of the reaction vessel. Since the stirring torque of the stirrer increased, the temperature was raised to 250 ° C. in 8 minutes, and the pressure in the reaction vessel was reduced to 200 Pa or less in order to remove the generated phenol. After reaching a predetermined stirring torque, the reaction was terminated, and the formed reaction product was extruded into water, and then pelletized to obtain BHEPF / ISB / PEG # 1000 = 40.3 mol% / 59.4 mol% / 0. 3 mol% of polycarbonate resin A was obtained.

  The obtained polycarbonate resin A was vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Chemical Industries, screw diameter 25 mm, cylinder set temperature: 220 ° C.), T die (width 200 mm, set temperature: 220). ° C.), a chill roll (set temperature: 120 to 130 ° C.), and a film forming apparatus equipped with a winder, a 110 μm-thick original film was produced. A sample having a width of 6 cm and a length of 6 cm was cut out from the raw film, and thickness spots were measured. Using a batch type biaxial stretching apparatus (manufactured by Toyo Seiki Co., Ltd.), this sample was stretched at 720 mm / min (strain rate) so that R1 (550) was 130 ± 20 nm while adjusting the stretching temperature at 127 to 177 ° C. The film was uniaxially stretched 1 × 2.0 times at 1200% / min to obtain a retardation film. At this time, it extended | stretched in the perpendicular | vertical direction with respect to the extending | stretching state in the hold | maintained state (drawing ratio 1.0). As described above, a long retardation film having a thickness of 55 μm was obtained.

[First stress relaxation layer]
The pressure-sensitive adhesive layer constituting the first stress relaxation layer of this comparative example was produced by the following method.

(Acrylic polymer)
60 parts by weight of dicyclopentanyl acrylate (DCPMA, dicyclopentanyl methacrylate), 40 parts by weight of methyl methacrylate (MMA, methyl methacrylate), 3.5 parts by weight of α-thioglycerol as a chain transfer agent and a polymerization solvent 100 parts by weight of toluene was put into a four-necked flask, and these were stirred at 70 ° C. for 1 hour in a nitrogen atmosphere. Next, 0.2 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator is put into a four-necked flask and reacted at 70 ° C. for 2 hours, followed by reaction at 80 ° C. for 2 hours. I let you. Thereafter, the reaction solution was put in a 130 ° C. temperature atmosphere, and toluene, chain transfer agent and unreacted monomer were removed by drying to obtain a solid acrylic polymer. The weight average molecular weight (Mw) of this acrylic polymer was 5.1 × 10 ³ .

(Stress relaxation glue)
To a monomer mixture composed of 68 parts by weight of 2-ethylhexyl acrylate (2EHA), 14.5 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 17.5 parts by weight of 2-hydroxyethyl acrylate (HEA), After blending 0.035 parts by weight of a photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF) and 0.035 parts by weight of a photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF), viscosity ( BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) was irradiated with ultraviolet rays until it reached about 20 Pa · s to obtain a prepolymer composition in which a part of the monomer component was polymerized.

  Next, 5 parts by weight of the acrylic polymer, 0.30 parts by weight of hexanediol diacrylate (HDDA), a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to the prepolymer composition. ) 0.3 part by weight was added and mixed to obtain an acrylic pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied onto the release-treated surface of a release film (trade name “MRF # 38”, manufactured by Mitsubishi Plastics Co., Ltd.) so that the thickness after forming the pressure-sensitive adhesive layer was 100 μm. Then, an adhesive composition layer was formed, and then a release film (trade name “MRN # 38”, manufactured by Mitsubishi Plastics, Inc.) was bonded to the surface of the adhesive composition layer. Thereafter, UV irradiation is performed under the conditions of illuminance: 5 mW / cm 2 and light quantity: 1500 mJ / cm 2 to photocur the pressure-sensitive adhesive composition layer to form a pressure-sensitive adhesive layer, and separators are provided on both sides of the pressure-sensitive adhesive layer. A pressure-sensitive adhesive sheet (baseless type, pressure-sensitive adhesive layer thickness: 100 μm) was prepared.

[Optical laminate]
By laminating these so that the angle formed by the slow axis of the obtained retardation film and the absorption axis of the obtained polarizing film was 45 °, a laminated long film was produced.

  Next, a circularly polarizing plate was produced by cutting the obtained laminated long film into 15 cm × 1 cm.

  A (meth) acrylic resin film serving as a protective film was bonded to both surfaces of the obtained circularly polarizing plate via an adhesive to prepare an optical laminate. Further, the separator is peeled off from the pressure-sensitive adhesive sheet obtained as described above, and the pressure-sensitive adhesive constituting the first stress relaxation layer is bonded to the (meth) acrylic resin film serving as a protective film, thereby displaying an organic EL display. A laminate for an apparatus was produced. If the pressure-sensitive adhesive layer is exposed, it will be difficult to perform a 180 ° folding resistance test described later. Therefore, a PET substrate having a thickness of 38 μm is formed on the pressure-sensitive adhesive layer of the laminate for an organic EL display device. The materials were pasted together.

  Various evaluation was performed as follows about the obtained polarizing film, retardation film, an optical laminated body, the adhesive layer which comprises a 1st stress relaxation layer, and the laminated body for organic electroluminescence displays. Table 1 shows properties of the obtained polarizing film, retardation film, optical laminate, pressure-sensitive adhesive layer constituting the first stress relaxation layer, and organic EL display laminate.

[Comparative Example 2]
A polarizing film, a retardation film, and an optical film under the same conditions as in Comparative Example 1 except that an adhesive having a storage elastic modulus at 25 ° C. of 0.20 MPa is used as an adhesive for the adhesive layer constituting the first stress relaxation layer. A laminate and a laminate for an organic EL display device were produced and produced, and various evaluations were performed as follows.

  The pressure-sensitive adhesive layer constituting the first stress relaxation layer of this comparative example was produced by the following method.

  2-ethylhexyl acrylate (2EHA) 32 parts by weight, isostearyl acrylate (ISTA) 48 parts by weight, 2-hydroxypropyl acrylate (2HPA) 20 parts by weight, two kinds of photopolymerization initiators (trade name: Irgacure 184, manufactured by BASF) 0.05 parts by weight and 0.05 parts by weight of a photopolymerization initiator (trade name: Irgacure 651, manufactured by BASF) were added to a four-necked flask to prepare a monomer mixture. Next, the monomer mixture was partially photopolymerized by exposing it to ultraviolet rays under a nitrogen atmosphere to obtain a partially polymerized product (acrylic polymer syrup) having a polymerization rate of about 10% by weight. To 100 parts by weight of the obtained acrylic polymer syrup, 0.02 part by weight of trimethylolpropane triacrylate (TMPTA) and a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) After adding 3 parts, these were uniformly mixed to prepare a monomer component.

  Next, the monomer component prepared above is peeled on the surface of a 38 μm thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having one surface peeled off with silicone, and the final thickness is 100 μm. It applied so that an application layer might be formed. Next, a 38 μm thick polyester film (trade name: Diafoil MRE, manufactured by Mitsubishi Resin Co., Ltd.) having one surface peeled with silicone on the surface of the applied monomer component, the peel-treated surface of the film is on the coating layer side It coat | covered so that it might become. Thereby, the coating layer of the monomer component was shielded from oxygen. Using a chemical light lamp (manufactured by Toshiba Corporation) on the sheet having the coating layer thus obtained, ultraviolet rays having an illuminance of 5 mW / cm 2 (measured with Topcon UVR-T1 having a maximum sensitivity of about 350 nm) are applied for 360 seconds. Irradiation was performed to cure the coating layer to form a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet (base material-less type, pressure-sensitive adhesive layer thickness: 100 μm) in which separators were provided on both sides of the pressure-sensitive adhesive layer was produced.

  Table 1 shows properties of the obtained polarizing film, retardation film, optical laminate, pressure-sensitive adhesive layer constituting the first stress relaxation layer, and organic EL display laminate.

[Evaluation]
(Measurement of thickness)
The thickness of the polarizing film, retardation film, protective film, and optical laminate was measured using a dial gauge (Mitutoyo).

(Measurement of storage elastic modulus of the first stress relaxation layer)
The separator was peeled off from the pressure-sensitive adhesive sheets of each Example and Comparative Example, and a plurality of pressure-sensitive adhesive sheets were laminated to prepare a test sample having a thickness of about 1.5 mm. This test sample was punched into a disk shape having a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to dynamic viscoelasticity measurement under the following conditions using “Advanced Rheometric Expansion System (ARES)” manufactured by Rheometric Scientific. The storage elastic modulus G ′ was read from the result.
(Measurement condition)
Deformation mode: torsion Measurement temperature: -40 ° C to 150 ° C
Temperature increase rate: 5 ° C / min Measurement frequency: 1Hz

(Measure folding resistance (times))
FIG. 7 shows a schematic diagram of a 180 ° folding resistance tester (manufactured by Imoto Seisakusho). This device has a mechanism in which a chuck on one side repeats 180 ° bending with a mandrel sandwiched in a thermostat, and the bending radius can be changed depending on the diameter of the mandrel. The test stops when the film breaks. In the test, the optical laminate of 1 cm × 15 cm obtained in each Example and Comparative Example was set in an apparatus, and the temperature was 25 ° C., the bending angle was 180 °, the bending radius was 5 mm, the bending speed was 2 seconds / time, and the weight was 100 g. It carried out in. Folding strength was evaluated by the number of times until the optical laminate was broken. Here, when the number of bendings reached 100,000, the test was terminated.

(Evaluation)
Table 1 shows the following. In Examples 1 to 3, the folding endurance of the optical laminate exceeded 100,000 times, but in Comparative Examples 1 and 2, the folding endurances were significantly lower than 40000 times, 20000 times and 100,000 times, respectively. That is, in the optical laminate of each example, the stress applied to the optical laminate can be effectively suppressed, the thickness of the optical laminate is 120 μm or less, and the first stress relaxation layer is stored at 25 ° C. When the elastic modulus is 0.05 to 0.15 MPa, the bending strength is sufficiently large, the thickness of the optical laminate exceeds 120 μm, and the storage elastic modulus at 25 ° C. of the first stress relaxation layer is 0.15 MPa. When exceeding, it turned out that bending strength becomes small remarkably.

  Although the present invention has been described above with reference to the drawings for specific embodiments, the present invention can be modified in various ways other than the configuration shown and described. Therefore, the present invention is not limited to the configurations shown and described, and the scope should be defined only by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 100 Organic EL display device 101 Organic EL display panel 102 Window 110 Organic EL display device laminate 111 First stress relaxation layer 112 Transparent conductive layer 113 Second stress relaxation layer 114 Base material 115 Base material 120 Optical laminate 121 Polarization Film 122 Protective film 123 Phase difference layer 900 Organic EL display device 901 Organic EL display panels 912-1 and 912-2 Transparent conductive layers 915-1 and 915-2 Base film 916-1 and 916-2 Transparent conductive film 917 Spacer 920 Optical laminated body 921 Polarizing film 922-1, 922-2 Protective film 923 Retardation layer 930 Touch panel

Claims (7)

An optical laminate;
A first stress relaxation layer;
Including
The optical laminate is
A polarizing film made of a polyvinyl alcohol-based resin having a thickness of 12 μm or less in which a dichroic material is oriented;
A protective film of a transparent resin material bonded to the first surface of the polarizing film;
A retardation film bonded to a second surface different from the first surface of the polarizing film;
Including
The first stress relaxation layer has a storage elastic modulus at 25 ° C. of 0.05 to 0.15 MPa, and is disposed on the side opposite to the retardation film with respect to the protective film,
The thickness of the optical laminate is 120 μm or less, and the optical laminate is configured to be bendable.
A laminate for an organic EL display device.   The laminate for an organic EL display device according to claim 1, wherein a foldable transparent conductive layer constituting a touch sensor is further disposed on the opposite side of the retardation film from the protective film.   The laminate for an organic EL display device according to claim 2, wherein a second stress relaxation layer is further disposed on the side opposite to the retardation film with respect to the transparent conductive layer.   The laminate for an organic EL display device according to claim 1, wherein a foldable transparent conductive layer constituting a touch sensor is further disposed between the protective film and the first stress relaxation layer.   The laminate for an organic EL display device according to claim 4, wherein a second stress relaxation layer is further disposed on the opposite side of the retardation film from the protective film. A laminate for an organic EL display device according to any one of claims 1 to 5,
An organic EL display panel configured to be bendable;
Including
The organic EL display device laminate is disposed on the viewing side with respect to the organic EL display panel,
Configured to be bendable,
Organic EL display device.   The organic EL display device according to claim 6, wherein a window is disposed on the viewing side with respect to the organic EL display device laminate.

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