JP2020060708A - Optical laminate and display device - Google Patents

Abstract

To provide an optical laminate that includes a front plate and one or more adhesive layers and with which the distortion of a reflection image appearing on the front plate surface is suppressed, and a display device that includes the optical laminate.SOLUTION: Provided is an optical laminate including a front plate, an adhesive layer (A), a polarizer layer, n adhesive layers (B) (n=any integer greater than or equal to 0), and a support base in the order stated, the optical laminate satisfying formula: 0.2≤T/C(in the formula, T represents the thickness of front plate [μm] and Crepresents a total of creep value C[%] at 25°C of each of adhesive layers arranged between the front plate and the support base). Also provided is a display device that includes the optical laminate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical laminate and a display device.

  2. Description of the Related Art As various display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices, a configuration is known in which a front plate is provided on the outermost surface on the viewing side for the purpose of protecting the screen.

  For example, International Publication No. 2017/204228 (Patent Document 1) discloses a laminate including a resin film having a predetermined surface roughness and an adhesive layer arranged on one surface thereof and having a predetermined loss tangent. It is described that it is applied to the front plate.

International Publication No. 2017/204228

The front plate may be incorporated on the viewing side of a display element (a liquid crystal cell, an organic EL display element, etc.) included in the display device as a laminate of the front plate and one or more other optical members. Usually, the front plate, the other optical member, and the other optical members are laminated via a pressure-sensitive adhesive layer or an adhesive layer.
In the above laminate including the front plate and one or more adhesive layers, when the reflection image reflected on the surface of the front plate is observed, the reflection image may appear distorted. The laminated body that causes such distortion of the reflected image may reduce the visibility of the screen of the display device.

  It is an object of the present invention to provide an optical layered body including a front plate and one or more adhesive layers, in which distortion of a reflected image reflected on the surface of the front plate is suppressed, and a display device including the optical layered body. To do.

The present invention provides the following optical laminated body display device.
[1] Front plate, pressure-sensitive adhesive layer (A), polarizer layer, and n layer [n represents any integer of 0 or more. ] The pressure-sensitive adhesive layer (B) and a supporting base material in this order,
Formula (1) below:
0.2 ≦ T / C _total (1)
[In Formula (1),
T represents the thickness [μm] of the front plate.
C _total represents the total creep value C [%] at 25 ° C. of each pressure-sensitive adhesive layer arranged between the front plate and the supporting base material. ]
An optical laminated body that satisfies the requirements.
[2] The following formula (2):
T / C _total ≦ 1.2 (2)
[In the formula (2), T and C _total represent the same meaning as described above. ]
The optical laminate according to [1], which further satisfies
[3] The optical laminate according to [1] or [2], wherein n is any integer of 1 or more.
[4] The optical layered body according to any one of [1] to [3], further including one or more retardation layers disposed between the polarizer layer and the supporting substrate.
[5] The optical layered body according to [4], wherein the retardation layer contains a cured product of a polymerizable liquid crystal compound.
[6] The optical layered body according to any one of [1] to [5], wherein the polarizer layer contains a cured product of a polymerizable liquid crystal compound.
[7] A display device including the optical layered body according to any one of [1] to [6].

  An optical laminate including a front plate and one or more adhesive layers, in which distortion of a reflected image reflected on the front plate surface is suppressed, and a display device including the same can be provided.

It is a schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention. It is a schematic sectional drawing which shows another example of the optical laminated body which concerns on this invention. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 1. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 1. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 1. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 1. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 1. FIG. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 2. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 2. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the optical layered body in Example 2. It is a schematic diagram explaining the method of a flexibility test.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the following drawings, the scales are appropriately adjusted and shown for easy understanding of the respective components, and the scales of the respective components shown in the drawings do not necessarily match the actual scales of the components.

In the present specification, the meanings or definitions of the following terms are as follows.
The “optical laminated body” is a laminated body applied to an optical device such as a display device, and is a laminated body composed of two or more layers. The two or more layers forming the optical layered body may be, independently of each other, a plate, a sheet, a film, a coating layer formed by including a step of applying a coating liquid for forming a layer, or the like. Examples of the display device include image display devices such as liquid crystal display devices and organic EL display devices.
The optical laminate according to the present invention has a front plate, a pressure-sensitive adhesive layer (A), a polarizer layer, and an n layer [n represents any integer of 0 or more. ] The pressure-sensitive adhesive layer (B) and a supporting substrate are included in this order.
The optical laminate according to the present invention is a display element (a liquid crystal cell, an organic EL display element, an inorganic EL display element) included in a display device with the front plate facing outward (the side opposite to the display element side, that is, the viewing side). (A plasma display element, a field emission display element, etc.).

The “adhesive layer” refers to a layer composed of an adhesive or a layer obtained by subjecting the layer to some treatment.
The "adhesive" is also called a pressure sensitive adhesive.
In the present specification, the “adhesive” refers to an adhesive other than the pressure-sensitive adhesive (pressure-sensitive adhesive), and is clearly distinguished from the pressure-sensitive adhesive.
The “adhesive layer” refers to a layer formed of an adhesive or a layer obtained by subjecting the layer to some treatment.
The pressure-sensitive adhesive layer and the adhesive layer can be clearly distinguished in terms of physical properties. For example, regarding the storage elastic modulus as the physical properties, generally, the adhesive layer exhibits a storage elastic modulus of 5.0 MPa or less at 25 ° C., and the adhesive layer exhibits a storage elastic modulus of 500 MPa or more at 25 ° C.

The adhesive layer (A) is an adhesive layer arranged between the front plate and the polarizer layer. The optical layered body can include one layer or two or more layers as the pressure-sensitive adhesive layer (A), but one layer is preferable.
The pressure-sensitive adhesive layer (B) refers to a pressure-sensitive adhesive layer arranged between the polarizer layer and the supporting base material. The optical layered body does not need to include the pressure-sensitive adhesive layer (B), and may include one or more pressure-sensitive adhesive layers as the pressure-sensitive adhesive layer (B).

  The “front plate” is a member arranged on the outermost surface (the outermost surface on the viewing side) of the optical laminate. In the present specification, the “front plate” is not limited to the case where the member is a plate, and may be a sheet or a film.

  “(Meth) acrylic” means at least one selected from the group consisting of acrylic and methacrylic. The same applies to other terms with "(meta)".

The term “flexible” means that the optical layered body can be bent without cracks when bent so that the radius of curvature of the inner surface of the optical layered body is 1 mm in at least one direction in the plane of the optical layered body. It means possible.
When the optical layered body is repeatedly bent in at least one direction in the plane so that the radius of curvature of the inner surface of the optical layered body is 1 mm, cracks are preferably generated even when the number of bending times is 10,000. Absent.

<Optical laminate>
[1] Outline of Optical Laminate and Shape of Layer Structure The optical laminate according to the present invention (hereinafter, also simply referred to as “optical laminate”) includes a front plate, an adhesive layer (A), and a polarizer. Layer and n layer [n represents any integer of 0 or more. ] The pressure-sensitive adhesive layer (B) and a supporting substrate are included in this order.
The pressure-sensitive adhesive layer (A) is usually one layer.
N representing the number of the pressure-sensitive adhesive layer (B) may be 0, but is preferably any integer of 1 or more, more preferably 1 or more and 3 or less, and further preferably 1 or It is 2.
When n is 2 or more, the plurality of pressure-sensitive adhesive layers are usually arranged apart from each other (with another layer interposed).

  The optical layered body may further include one or more retardation layers. The retardation layer is usually arranged between the polarizer layer and the supporting substrate. The retardation layer can be laminated on another layer (including another retardation layer) via a pressure-sensitive adhesive layer or an adhesive layer.

The optical layered body may include layers other than the layers described above. The other layer is arranged, for example, between the pressure-sensitive adhesive layer (A) and the polarizer layer, between the polarizer layer and the supporting base material, or outside the supporting base material (on the side opposite to the polarizer layer side). Can be done.
For example, the optical layered body can include a thermoplastic resin film layer disposed between the pressure-sensitive adhesive layer (A) and the polarizer layer. For example, the optical layered body may include a thermoplastic resin film layer laminated on the front plate side surface and / or the supporting base material side surface of the polarizer layer, for example, with an adhesive layer interposed therebetween. Further, a substrate film to which the coating liquid is applied when the layer is formed by coating the coating liquid may be incorporated in the optical layered body together with the above layer.
For example, the optical layered body can include a pressure-sensitive adhesive layer (C) arranged on the outside of the supporting substrate. This pressure-sensitive adhesive layer (C) can be used, for example, for bonding to a display element.

  The thickness of the optical laminate is not particularly limited because it varies depending on the function required for the optical laminate and the application of the optical laminate, but is, for example, 50 μm or more and 1000 μm or less, preferably 100 μm or more and 500 μm or less, and more preferably Is 100 μm or more and 300 μm or less.

The plan view shape of the optical layered body may be, for example, a rectangular shape, preferably a rectangular shape having long sides and short sides, and more preferably a rectangle. When the plan view shape of the optical laminated body is a rectangle, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, and preferably 50 mm or more and 600 mm or less. The length of the short side is, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less.
When the plan view shape of the optical layered body is a rectangular shape, the lengths of the respective sides of the layers forming the optical layered body may be the same as each other. The corners of each layer constituting the optical layered body may be rounded, end portions may be cut out, or holes may be formed.

[2] Example of Layer Structure of Optical Laminated Body FIG. 1 is a schematic cross-sectional view showing an example of the optical laminated body according to the present invention.
The optical layered body 1 shown in FIG. 1 includes a front plate 10, a first adhesive layer 20 which is an adhesive layer (A), a polarizer layer 30, a second adhesive layer 40 which is an adhesive layer (B), The first retardation layer 50, the third pressure-sensitive adhesive layer 60 that is the pressure-sensitive adhesive layer (B), the second retardation layer 70, and the supporting base material 80 are provided in this order.
In the optical layered body 1, an adhesive layer may be used instead of the second pressure-sensitive adhesive layer 40. In the optical layered body 1, an adhesive layer may be used instead of the third pressure-sensitive adhesive layer 60. In the optical layered body 1, an adhesive layer may be used instead of the second pressure-sensitive adhesive layer 40, and an adhesive layer may be used instead of the third pressure-sensitive adhesive layer 60.
The first pressure-sensitive adhesive layer 20 is preferably in direct contact with the front plate 10.

FIG. 2 is a schematic sectional view showing another example of the optical laminate according to the present invention. The optical layered body 2 shown in FIG. 2 is the same layer as the optical layered body 1 shown in FIG. 1 except that it has a thermoplastic resin film layer 90 between the first adhesive layer 20 and the polarizer layer 30. Have a configuration.
In the optical layered body 2, an adhesive layer may be used instead of the second pressure-sensitive adhesive layer 40. In the optical layered body 2, an adhesive layer may be used instead of the third pressure-sensitive adhesive layer 60. In the optical layered body 2, an adhesive layer may be used instead of the second pressure-sensitive adhesive layer 40, and an adhesive layer may be used instead of the third pressure-sensitive adhesive layer 60.
The first pressure-sensitive adhesive layer 20 is preferably in direct contact with the front plate 10 and the thermoplastic resin film layer 90. That is, it is preferable that the front plate 10 and the thermoplastic resin film layer 90 are directly bonded by the first pressure-sensitive adhesive layer 20.

[3] About Formulas (1) and (2) The optical layered body according to the present invention satisfies the formula (1). Accordingly, it is possible to suppress the distortion of the reflected image reflected on the surface of the front plate 10.
The inventors of the present invention have conducted diligent research in order to suppress the distortion of the reflected image reflected on the surface of the front plate 10, and the distortion of the reflected image and the thickness and optical of the front plate arranged on the outermost side of the optical laminate. When the pressure-sensitive adhesive layer included in the laminate has a relationship with the strain characteristic when a stress is applied, and when T / C _total in the above formula (1) is a predetermined value or more, the distortion of the reflected image is effective. It was found that it can be suppressed to.
From the viewpoint of suppressing the distortion of the reflected image, T / C _total in the above formula (1) is preferably 0.22 or more, more preferably 0.25 or more, and further preferably 0.30 or more. .

On the other hand, from the viewpoint of enhancing the flexibility of the optical laminate and the display device including the same, the optical laminate according to the present invention preferably satisfies the above formula (2). From the viewpoint of enhancing the flexibility of the optical laminate and the display device including the same, T / C _total in the above formula (2) is more preferably 1.18 or less, further preferably 1.15 or less, and even more It is preferably 1.10 or less.

As described above, when the optical layered body is repeatedly bent in at least one direction in the plane so that the radius of curvature of the inner surface of the optical layered body is 1 mm, the number of bending times is preferably 10,000 times. Does not crack.
When the optical layered body is repeatedly bent in at least one direction in the plane so that the radius of curvature of the inner surface of the optical layered body is 1 mm, more preferably, even if the number of bending times is about 50,000, cracks occur. Does not occur, more preferably, cracks do not occur even when the number of flexing is about 80,000, and even more preferably, cracks do not occur even when the number of flexing is about 100,000.
In the optical layered body, it is preferable that the number of times of bending that does not generate cracks when the above-described repeated bending is performed is within the above range in at least one direction in the plane and a direction orthogonal thereto.
The display device to which the optical laminate having good flexibility is applied can be used as a flexible display that can be bent, bent, or wound.

C _total in the formulas (1) and (2) represents the total creep value C [%] at 25 ° C. of each pressure-sensitive adhesive layer arranged between the front plate 10 and the supporting base material 80. The pressure-sensitive adhesive layer arranged between the front plate 10 and the supporting base material 80 refers to a pressure-sensitive adhesive layer corresponding to the pressure-sensitive adhesive layer (A) or the pressure-sensitive adhesive layer (B), and is located outside the supporting base material 80. The adhesive layer (C) arranged is not included.
The creep value C at 25 ° C. of each pressure-sensitive adhesive layer is measured according to the method described in the section of Examples below.

[4] Front Plate The front plate 10 is preferably a plate that can transmit light. Front plate 10 may be composed of only one layer or may be composed of two or more layers.
Examples of the front plate 10 include a glass plate-shaped body (for example, a glass plate, a glass film, etc.) and a resin-made plate-shaped body (for example, a resin plate, a resin sheet, a resin film, etc.).
Among the above, from the viewpoint of flexibility of the optical laminate and the display device including the same, a resin plate-like body such as a resin film is preferable. When a glass plate is used, the problem of distortion of the reflected image is unlikely to occur in the first place, depending on the thickness of the plate.

Examples of the thermoplastic resin that constitutes the resin plate such as a resin film include chain polyolefin resins (polyethylene resin, polypropylene resin, polymethylpentene resin, etc.), cyclic polyolefin resins (norbornene resin). Polyolefin resin such as resin); Cellulose resin such as triacetyl cellulose; Polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; Polycarbonate resin; Ethylene-vinyl acetate resin; Polystyrene resin; Polyamide -Based resins; polyetherimide-based resins; (meth) acrylic-based resins such as polymethyl (meth) acrylate resins; polyimide-based resins; polyethersulfone-based resins; polysulfone-based resins; polyvinyl chloride-based resins; polyvinyl chloride Isopropylidene-based resin, polyvinyl alcohol resin, polyvinyl acetal resin; polyether ketone resins; polyether ether ketone resins; poly (ether sulfone) resins; polyamide-imide resins.
The thermoplastic resins may be used alone or in combination of two or more.
Among them, from the viewpoint of flexibility, strength, and transparency, polyimide resin, polyamide resin, and polyamideimide resin are preferably used as the thermoplastic resin forming the front plate 10.

The front plate 10 may be a film in which a hard coat layer is provided on at least one surface of the base film to further improve the hardness. The above-mentioned resin film can be used as the substrate film.
The hard coat layer may be formed on one surface of the base film, or may be formed on both surfaces. By providing the hard coat layer, hardness and scratch resistance can be improved.
The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resin, silicone resin, polyester resin, urethane resin, amide resin, and epoxy resin. The hard coat layer may contain an additive in order to improve the strength. The additive is not limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof.

  The front plate 10 has not only a function of protecting the front surface (screen) of the display device (function as a window film) but also a function as a touch sensor, a blue light cut function, a viewing angle adjustment function, and the like. May be.

The thickness T of the front plate 10 is appropriately selected so as to satisfy the above expression (1), preferably the above expression (2).
The thickness T of the front plate 10 is preferably 20 μm or more and 2000 μm or less, and more preferably 25 μm or more and 1500 μm or less from the viewpoint of suppressing the distortion of the reflected image and the flexibility of the optical laminate and the display device including the same. It is more preferably 30 μm or more and 1000 μm or less, 40 μm or more and 500 μm or less, further 40 μm or more and 200 μm or less, and even more preferably 40 μm or more and 100 μm or less.

From the viewpoint of suppressing the distortion of the reflected image and the flexibility of the optical laminate and the display device including the same, the tensile elastic modulus of the front plate 10 is preferably 2.0 GPa or more and 10.0 GPa or less, more preferably 3 GPa or less. It is not less than 0.0 GPa and not more than 9 GPa, more preferably not less than 4.0 GPa and not more than 8.0 GPa. The tensile modulus of the front plate 10 is measured under the following conditions.
Measurement environment: temperature 23 ° C, relative humidity 55% RH
Sample size: width: 4 mm, length: 110 mm (length direction = tensile direction)
Tensile speed: 4 mm / min.

[5] Adhesive layer (A)
The pressure-sensitive adhesive layer (A) is a pressure-sensitive adhesive layer arranged between the front plate 10 and the polarizer layer 30, and is the first pressure-sensitive adhesive layer in the optical laminates 1 and 2 shown in FIGS. 1 and 2. 20 corresponds to this.
The optical layered body can include one layer or two or more layers as the pressure-sensitive adhesive layer (A), but one layer is preferable.

  The pressure-sensitive adhesive layer (A) can be composed of a pressure-sensitive adhesive composition containing a resin such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a polyvinyl ether resin as a main component. Above all, a pressure-sensitive adhesive composition containing a (meth) acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, hexyl (meth) acrylate, (Meth) acryl such as octyl (meth) acrylate, lauryl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate Polymers or copolymers having one or more acid esters as monomers are preferably used.
It is preferable to copolymerize a polar monomer with the base polymer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl ( Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like such as (meth) acrylate.

  The pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. As the cross-linking agent, a metal ion having a valence of 2 or more and forming a carboxylic acid metal salt with a carboxyl group; a polyamine compound forming an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form an ester bond with a carboxyl group; and polyisocyanate compounds that form an amide bond with a carboxyl group. Of these, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with an active energy ray such as an ultraviolet ray or an electron beam, and has adhesiveness even before irradiation with the active energy ray. It is a pressure-sensitive adhesive composition having a property that it can be brought into close contact with an adherend such as, and is cured by irradiation with an active energy ray to adjust the adhesion and the like.
The active energy ray-curable pressure-sensitive adhesive composition is preferably UV-curable. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer or the like may be contained.
As the active energy ray-polymerizable compound, for example, a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; a compound obtained by reacting two or more functional group-containing compounds, and at least one in the molecule Examples thereof include (meth) acryl-based compounds such as (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having two (meth) acryloyloxy groups.

  The pressure-sensitive adhesive composition includes fine particles for imparting light-scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, tackifiers, fillers (metal powder and other inorganic powders). Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, photopolymerization initiators, and other additives.

  The first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) can be formed by applying, for example, an organic solvent diluted solution of the above-mentioned pressure-sensitive adhesive composition onto a substrate and drying. When the active energy ray-curable pressure-sensitive adhesive composition is used, the formed pressure-sensitive adhesive layer can be irradiated with an active energy ray to give a cured product having a desired degree of curing.

The creep value C of the first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) is, for example, its thickness or elastic modulus, the molecular weight of the base polymer, the degree of cure when an active energy ray-curable pressure-sensitive adhesive composition is used, and the like. Can be controlled by adjusting.
The creep value C of the first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) at 25 ° C. is, for example, 10% or more and 300% or less, preferably 20% or more and 200% or less, and 100% or less. Good.

The storage elastic modulus at 25 ° C. of the first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) is usually 0. It is 01 MPa or more and 5 MPa or less, preferably 0.02 MPa or more and 3 MPa or less, more preferably 0.03 MPa or more and 2 MPa or less, and may be 0.10 MPa or more and may be 0.50 MPa or more.
The storage elastic modulus of the first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) is determined by the selection of the material forming the first pressure-sensitive adhesive layer 20 (pressure-sensitive adhesive layer (A)) and the thickness of the first pressure-sensitive adhesive layer 20. , The first pressure-sensitive adhesive layer 20 can be adjusted according to the manufacturing conditions or a combination thereof.
The storage elastic modulus at 25 ° C. of the pressure-sensitive adhesive layer is measured according to the method described in the Examples section below.

  The thickness of the first pressure-sensitive adhesive layer 20 is, for example, 2 μm or more and 100 μm or less, preferably 3 μm or more and 50 μm or less, from the viewpoint of adhesion between layers via the first adhesive layer 20 and control of the creep value C. It is preferably 5 μm or more and 30 μm or less.

[6] Polarizer Layer Examples of the polarizer layer 30 include a stretched film or a stretched layer on which a dye having absorption anisotropy is adsorbed, and a layer obtained by coating and curing a dye having absorption anisotropy.
Examples of the dye having absorption anisotropy include dichroic dyes. As the dichroic pigment, specifically, iodine or a dichroic organic dye is used. The dichroic organic dye includes C.I. I. A dichroic direct dye composed of a disazo compound such as DIRECT RED 39 and a dichroic direct dye composed of a compound such as trisazo or tetrakisazo are included.
As the polarizer layer formed by applying and curing a dye having absorption anisotropy, a composition containing a dichroic dye having liquid crystallinity or a composition containing a dichroic dye and a polymerizable liquid crystal is applied and cured. Examples thereof include a polarizer layer containing a cured product of a polymerizable liquid crystal compound such as a layer obtained in this way.
A polarizer layer obtained by coating and curing a dye having absorption anisotropy is preferable because it has no limitation in the bending direction as compared with a stretched film or a stretched layer on which a dye having absorption anisotropy is adsorbed. Therefore, in at least one direction in the plane and the direction orthogonal thereto, and further in all the directions in the plane, in order to obtain an optical layered body in which the number of times of bending that does not cause cracks when the above repeated bending is performed is in the above range. Then, as the polarizer layer 30, it is preferable to use a layer by applying a dye having absorption anisotropy and curing it.

[6-1] Polarized layer which is a stretched film or a stretched layer The polarizer layer 30 which is a stretched film in which a dye having absorption anisotropy is adsorbed is usually a step of uniaxially stretching a polyvinyl alcohol-based resin film, polyvinyl. A step of adsorbing the dichroic dye by dyeing the alcohol-based resin film with the dichroic dye, a step of treating the polyvinyl alcohol-based resin film on which the dichroic dye is adsorbed with a boric acid aqueous solution, and boric acid It can be manufactured through a process of washing with water after treatment with an aqueous solution.
The thickness of the polarizer layer 30 is, for example, 2 μm or more and 40 μm or less. The thickness of the polarizer layer may be 5 μm or more, 20 μm or less, further 15 μm or less, and even further 10 μm or less.

  The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith is used. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

  The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 or more and 10000 or less, preferably 1500 or more and 5000 or less.

The polarizer layer 30, which is a stretched layer in which a dye having absorption anisotropy is adsorbed, is usually a step of applying a coating liquid containing the polyvinyl alcohol resin onto a substrate film, and the resulting laminated film is uniaxially stretched. The step of dyeing the polyvinyl alcohol-based resin layer of the uniaxially stretched laminated film with a dichroic dye to adsorb the dichroic dye to form the polarizer layer 30, and the dichroic dye is adsorbed. It can be manufactured through a step of treating the film with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution.
If necessary, the base film may be peeled off from the polarizer layer 30. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described later.

The polarizer layer 30, which is a stretched film or a stretched layer, may be incorporated in the optical laminate in a form in which a thermoplastic resin film is attached to one side or both sides thereof. This thermoplastic resin film can function as a protective film for the polarizer layer 30 or a retardation film.
The thermoplastic resin film is, for example, a polyolefin resin such as a chain polyolefin resin (such as polypropylene resin) or a cyclic polyolefin resin (such as norbornene resin); a cellulose resin such as triacetyl cellulose; polyethylene terephthalate, polyethylene The film may be a polyester resin such as phthalate or polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin; or a mixture thereof.
The thickness of the thermoplastic resin film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, further preferably 80 μm or less, and still more preferably 60 μm or less from the viewpoint of thinning. And usually 5 μm or more, preferably 20 μm or more.
The thermoplastic resin film may or may not have a retardation.
The thermoplastic resin film can be attached to the polarizer layer 30 using, for example, an adhesive layer.

[6-2] Polarizer layer formed by coating and curing a dye having absorption anisotropy The polarizer layer formed by coating and curing a dye having absorption anisotropy is a polymerizable two-layer liquid crystal layer having liquid crystallinity. Polymerization of a layer or the like obtained by applying a composition containing a color dye or a composition containing a dichroic dye and a polymerizable liquid crystal to a base film (or an alignment film formed on the base film) and curing the composition. Examples include a polarizer layer containing a cured product of a liquid crystalline liquid crystal compound.
If necessary, the base film or both the base film and the alignment film may be peeled off from the polarizer layer 30. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described above.
The polarizer layer 30 obtained by applying a dye having absorption anisotropy and curing the dye may be incorporated in the optical laminate in a form in which a thermoplastic resin film is attached to one surface or both surfaces thereof. As the thermoplastic resin film, the same thermoplastic resin film as that which can be used for the polarizer layer which is a stretched film or a stretched layer can be used.
The thermoplastic resin film can be attached to the polarizer layer 30 using, for example, an adhesive layer.
Specific examples of the polarizer layer 30 formed by coating and curing a dye having absorption anisotropy include those described in JP 2012-33249 A and the like.

  The thickness of the polarizer layer 30 formed by coating and curing a dye having absorption anisotropy is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 5 μm or less.

[7] Adhesive layer (B)
The pressure-sensitive adhesive layer (B) is a pressure-sensitive adhesive layer arranged between the polarizer layer 30 and the supporting base material 80, and is the second pressure-sensitive adhesive in the optical laminates 1 and 2 shown in FIGS. 1 and 2. The layer 40 and the third pressure-sensitive adhesive layer 60 correspond to this.
However, the optical layered body is not limited to these embodiments and may not include the pressure-sensitive adhesive layer (B), and may have one or more pressure-sensitive adhesive layers as the pressure-sensitive adhesive layer (B). May be included. The number of pressure-sensitive adhesive layers (B) is preferably 1 or more, more preferably 1 or more and 3 or less, and further preferably 1 or 2.

The composition and components of the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer (B), the type of the pressure-sensitive adhesive composition (whether or not it is an active energy ray-curable type or a thermosetting type), the pressure-sensitive adhesive layer (B) Additives that can be blended, the method for producing the pressure-sensitive adhesive layer (B), the thickness of the pressure-sensitive adhesive layer (B), the creep value C of the pressure-sensitive adhesive layer (B) at 25 ° C. and its range, and the pressure-sensitive adhesive layer (B). Regarding the storage elastic modulus at 25 ° C and the range thereof, the description about the pressure-sensitive adhesive layer (A) is cited.
One or two or more pressure-sensitive adhesive layers corresponding to the pressure-sensitive adhesive layer (B) are independently the same as the pressure-sensitive adhesive layer (A) in terms of thickness, creep value C at 25 ° C., storage elastic modulus at 25 ° C., etc. Or may be different.
When two or more pressure-sensitive adhesive layers corresponding to the pressure-sensitive adhesive layer (B) are present, these two or more pressure-sensitive adhesive layers are the same in thickness, creep value C at 25 ° C. and storage elastic modulus at 25 ° C. Or may be different.

[8] Supporting Base Material The supporting base material 80 is preferably a plate-like body capable of transmitting light. The supporting base material 80 may be composed of only one layer or may be composed of two or more layers. The support base material 80 can also be a display element such as a touch sensor or an organic EL display element.
As the support base material 80, similar to the front plate 10, for example, a glass plate-shaped body (for example, a glass plate, a glass film, etc.), a resin plate-shaped body (for example, a resin plate, a resin sheet, a resin film). Etc.) can be mentioned.
Among the above, from the viewpoint of flexibility of the optical laminate and the display device including the same, a resin plate-like body such as a resin film is preferable. The description of the front plate 10 is cited as a specific example of the thermoplastic resin forming the plate-shaped body made of a resin such as a resin film. The thermoplastic resin is preferably a cellulose resin, a (meth) acrylic resin, a cyclic polyolefin resin, a polyester resin, a polycarbonate resin, or the like.

  The thickness of the supporting substrate 80 is preferably 15 μm or more and 200 μm or less, more preferably 20 μm or more and 150 μm or less, further preferably 25 μm or more and 100 μm or less, and 80 μm or less from the viewpoint of thinning the optical laminate. Further, it may be 60 μm or less, and even 50 μm or less.

[9] Retardation Layer The optical layered body may further include one layer or two or more layers of retardation layers. The retardation layer is usually arranged between the polarizer layer 30 and the supporting substrate 80. The retardation layer can be laminated on another layer (including another retardation layer) via a pressure-sensitive adhesive layer or an adhesive layer.
The optical laminates 1 and 2 shown in FIGS. 1 and 2 include a first retardation layer 50 and a second retardation layer 70.

Examples of the retardation layer include a positive A plate such as a λ / 4 plate and a λ / 2 plate, and a positive C plate.
The retardation layer may be, for example, a retardation film that can be formed from the thermoplastic resin film described above, or a layer formed by curing a polymerizable liquid crystal compound, that is, a cured product of the polymerizable liquid crystal compound. It may be a layer, but the latter is preferable.
The thickness of the retardation film may be the same as the thickness of the thermoplastic resin film described above. The thickness of the retardation layer formed by curing the polymerizable liquid crystal compound is, for example, 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 6 μm or less.

The retardation layer formed by curing the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound onto a substrate film and curing the composition. An orientation layer may be formed between the base film and the coating layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described above.
The retardation layer formed by curing the polymerizable liquid crystal compound may be incorporated in the optical laminate in a form having the alignment layer and / or the base film. The supporting base material 80 may be a base material film to which the composition is applied.

As described above, the pressure-sensitive adhesive layer or the adhesive layer may be used for laminating the retardation layer. This adhesive layer corresponds to the adhesive layer (B).
As the adhesive forming the adhesive layer, a water-based adhesive or an active energy ray curable adhesive can be used. Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane-based emulsion adhesive.

The active energy ray-curable adhesive refers to an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, for example, one containing a polymerizable compound and a photopolymerization initiator, one containing a photoreactive resin, Examples include those containing a binder resin and a photoreactive crosslinking agent.
Examples of the polymerizable compound include a photopolymerizable monomer such as a photocurable epoxy monomer, a photocurable (meth) acrylic monomer, and a photocurable urethane monomer, and an oligomer derived from the photopolymerizable monomer.
Examples of the photopolymerization initiator include those containing substances that generate active species such as neutral radicals, anion radicals, and cation radicals upon irradiation with active energy rays such as ultraviolet rays. As the active energy ray curable adhesive containing a polymerizable compound and a photopolymerization initiator, an adhesive containing a photocurable epoxy monomer and a photocationic polymerization initiator can be preferably used.

[10] Method for producing optical layered body The optical layered body can be produced by a method including a step of laminating the layers constituting the optical layered body via the pressure-sensitive adhesive layer or the adhesive layer. When laminating layers via a pressure-sensitive adhesive layer or an adhesive layer, one or both of the laminating surfaces should be subjected to surface activation treatment such as corona treatment in order to enhance adhesion. Is preferred.
The polarizer layer and the retardation layer can be formed directly on the thermoplastic resin film or the base film or via the alignment film, and the thermoplastic resin film or the base film is incorporated into the optical laminate. Alternatively, it may be separated from the polarizer layer or the retardation layer and may not be a constituent element of the optical laminate.
A specific method for manufacturing the optical layered body can be understood by referring to the section of Examples described later.

<Display device>
A display device according to the present invention includes the optical layered body according to the present invention. The display device is not particularly limited, and examples thereof include image display devices such as an organic EL display device, an inorganic EL display device, a liquid crystal display device, and an electroluminescent display device. The display device may have a touch panel function. The optical layered body is suitable for a flexible display device that can be bent or bent.
In the display device, the optical laminate is arranged on the viewing side of the display element included in the display device with the front plate facing outward (the side opposite to the display element side, that is, the viewing side).

The display device according to the present invention can be used as a mobile device such as a smartphone or a tablet, a television, a digital photo frame, an electronic signboard, a measuring instrument or measuring instrument, office equipment, medical equipment, computer equipment, or the like.
The display device according to the present invention is excellent in the visibility of the screen because the distortion of the reflected image reflected on the surface of the front plate is suppressed.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
In the examples,% and parts indicating the content or the amount used are based on mass unless otherwise specified.

The measurement methods of the following items were as follows.
[A] Layer Thickness It was measured using a contact-type film thickness measuring device ("MS-5C" manufactured by Nikon Corporation).
However, the polarizer layer, the alignment film, and the retardation layer were measured using a laser microscope (“OLS3000” manufactured by Olympus Corporation).

[B] Storage elastic modulus of pressure-sensitive adhesive layer The pressure-sensitive adhesive layer sample stacked to have a thickness of 150 μm was measured by a torsion shearing method at a temperature of 25 ° C. using a rheometer (“MCR-301” manufactured by Anton Parr). The storage elastic modulus (G ′) [MPa] was measured under the condition of a frequency of 1 Hz.

[C] Adhesive layer creep value C
Using a rheometer (“MCR-300” manufactured by Anton Parr) for a cylindrical pressure-sensitive adhesive layer sample having a diameter of 8 mm (a sample having a thickness of 5 μm for the pressure-sensitive adhesive sheet A and a sample having a thickness of 25 μm for the pressure-sensitive adhesive sheet B), a temperature of 25 A time-strain curve when a torque of 1200 μNm was applied to the sample at 0 ° C. was obtained, and the strain change rate [%] at a time of 1200 seconds was taken as the creep value [%] of the pressure-sensitive adhesive layer.

[D] Tensile Elastic Modulus of Front Plate The tensile elastic modulus of the front plate 10 was measured under the following conditions.
Measurement environment: temperature 23 ° C, relative humidity 55% RH
Sample size: width: 4 mm, length: 110 mm (length direction = tensile direction)
Tensile speed: 4 mm / min.

<Example 1>
An optical laminate having the same structure as that shown in FIG. 2 was produced according to the following procedure.
(1) Preparation of Front Plate As the front plate 10, a polyimide film having a hard coat layer on both sides (total thickness: 30 μm) was prepared. The tensile elastic modulus of this front plate was 5.7 GPa.

(2) Preparation of Adhesive Sheet A An acrylic resin was obtained by reacting the following components at 55 ° C. with stirring under a nitrogen atmosphere.
Butyl acrylate: 70 parts Methyl acrylate: 20 parts Acrylic acid: 2.0 parts Radical polymerization initiator (2,2′-azobisisobutyronitrile): 0.2 parts Solvent (ethyl acetate): 80 parts The obtained acrylic resin was mixed with 1.0 part of a crosslinking agent (“Coronate L” manufactured by Tosoh Corporation) and 0.5 part of a silane coupling agent (“X-12-981” manufactured by Shin-Etsu Silicon Co., Ltd.), and the whole was mixed. Ethyl acetate was added so that the solid content concentration was 10% to obtain an adhesive composition.
The obtained pressure-sensitive adhesive composition was applied to the release-treated surface of a release-treated polyethylene terephthalate film (release film B, thickness 38 μm) using an applicator so that the thickness after drying would be 5 μm. The coating layer was dried at 100 ° C for 1 minute to obtain a film having an adhesive layer. Then, on the exposed surface of the pressure-sensitive adhesive layer, another polyethylene terephthalate film (release film A, thickness 38 μm) subjected to release treatment was attached. Then, it was aged at a temperature of 23 ° C. and a relative humidity of 50% RH for 7 days.
In this way, a pressure-sensitive adhesive sheet A composed of release film A / pressure-sensitive adhesive layer / release film B was produced.
The storage elastic modulus at 25 ° C. of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet A was 1.00 MPa.

(3) Preparation of Laminate A Having Polarizer Layer (3-1) Preparation of Polymerizable Liquid Crystal Compound Polymerizable liquid crystal compound represented by the following formula (1-6) (hereinafter, referred to as “compound (1-6)”). And a polymerizable liquid crystal compound represented by the following formula (1-7) (hereinafter, also referred to as “compound (1-7)”) by Lub et al. Recl. Trav. Chim. Prepared according to the method described in Pays-Bas, 115, 321-328 (1996).

(3-2) Preparation of dichroic dye As a dichroic dye, the examples of JP-A-2013-101328 represented by the following formulas (2-1a), (2-1b) and (2-3a) are used. The azo dye described was prepared.

(3-3) Preparation of Composition for Forming Polarizer Layer 75 parts of compound (1-6) which is a polymerizable liquid crystal compound and 25 parts of compound (1-7), a formula (2-1a) which is a dichroic dye. Parts of azo dyes represented by (2-1b) and (2-3a), 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one as a polymerization initiator (BASF Japan "Irgacure369") 6 parts, and a polyacrylate compound as a leveling agent (BYK-Chemie "BYK-361N") 1.2 parts were mixed with toluene 400 parts of the solvent and obtained. A composition for forming a polarizer layer was prepared by stirring the mixture at 80 ° C. for 1 hour.

(3-4) Preparation of Composition for Alignment Film Formation A composition for alignment film formation was prepared by dissolving a polymer having a photoreactive group consisting of the following structural units in cyclopentanone to a concentration of 5%. Prepared.

(3-5) Preparation of Laminate A Having Polarizer Layer A composition for forming an alignment film obtained in the above (3-4) was formed on a triacetyl cellulose (TAC) film (thickness 25 μm) by a bar coating method. The composition was applied and heat-dried in a drying oven at 80 ° C. for 1 minute.
The obtained dried coating film was subjected to polarized UV irradiation treatment to form a first alignment film (AL1). In the polarized UV treatment, light emitted from a UV irradiation device (“SPOT CURE SP-7” manufactured by USHIO INC.) Is transmitted through a wire grid (“UIS-27132 ##” manufactured by USHIO INC.). The measurement was performed under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² . The thickness of the first alignment film (AL1) was 100 nm.

On the formed first alignment film (AL1), the composition for forming a polarizer layer obtained in the above (3-3) was applied by a bar coating method, and after heating and drying in a drying oven at 120 ° C. for 1 minute. , Cooled to room temperature. The polarizer layer 30 (pol) was formed by irradiating the dried coating film with ultraviolet rays with an integrated light amount of 1200 mJ / cm ² (365 nm standard) using the UV irradiation device. The thickness of the obtained polarizer layer 30 was 1.8 μm.
In this way, a laminate A composed of the polarizer layer 30 / first alignment film (AL1) / thermoplastic resin film layer 90 (TAC film) was obtained.

(4) Preparation of Laminate C Having First Retardation Layer (4-1) Preparation of First Retardation Layer-Forming Composition Each component shown below was mixed, and the resulting mixture was heated at 80 ° C. for 1 hour. The first retardation layer forming composition was prepared by stirring.
Compound b-1 represented by the following formula: 80 parts

下記式で示される化合物ｂ−２：２０部

Compound b-2 represented by the following formula: 20 parts

重合開始剤（ＢＡＳＦジャパン社製「Ｉｒｇａｃｕｒｅ３６９」、２−ジメチルアミノ−２−ベンジル−１−（４−モルホリノフェニル）ブタン−１−オン）：６部
レベリング剤（ＢＹＫ−Ｃｈｅｍｉｅ社製「ＢＹＫ−３６１Ｎ」、ポリアクリレート化合物）：０．１部
溶剤（シクロペンタノン）：４００部

Polymerization initiator (“Irgacure369” manufactured by BASF Japan Ltd., 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one): 6 parts Leveling agent (“BYK-361N manufactured by BYK-Chemie”) , Polyacrylate compound): 0.1 part Solvent (cyclopentanone): 400 parts

(4-2) Preparation of Laminate C Having First Retardation Layer A polyethylene terephthalate (PET) film having a thickness of 100 μm was prepared as a base film, and the orientation obtained in (3-4) above was provided on the film. The film-forming composition was applied by the bar coating method and heated and dried in a drying oven at 80 ° C. for 1 minute.
The obtained dried coating film was subjected to polarized UV irradiation treatment to form a third alignment film (AL3). The polarized UV treatment was performed using the above UV irradiation device under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² . The polarization direction of the polarized UV was set to be 45 ° with respect to the absorption axis of the polarizer layer 30.

On the formed 3rd alignment film (AL3), the composition for 1st retardation layer formation obtained by said (4-1) was apply | coated by the bar coating method, and it heat-dried for 1 minute in a 120 degreeC drying oven. Then, it cooled to room temperature. By irradiating the obtained dried coating film with ultraviolet rays having a cumulative light amount of 1000 mJ / cm ² (365 nm standard) under a nitrogen atmosphere using the UV irradiation device, the first retardation layer (first retardation layer) 50) was formed. The thickness of the obtained first retardation layer was 2.0 μm. The first retardation layer was a λ / 4 plate (QWP) showing a retardation value of λ / 4 in the in-plane direction.
In this way, a laminate C composed of the first retardation layer (QWP) / third alignment film (AL3) / base film (PET) was obtained.

(5) Preparation of Laminate B Having Second Retardation Layer (5-1) Preparation of Second Retardation Layer-Forming Composition Each component shown below was mixed, and the resulting mixture was heated at 80 ° C. for 1 hour. The composition for forming the second retardation layer was prepared by stirring.
Compound c-1 represented by the following formula (LC242, manufactured by BASF Japan Ltd.): 100 parts

重合開始剤（ＢＡＳＦジャパン社製「Ｉｒｇａｃｕｒｅ９０７」、２−メチル−４’−（メチルチオ）−２−モルホリノプロピオフェノン）：２．６部
レベリング剤（ＢＹＫ−Ｃｈｅｍｉｅ社製「ＢＹＫ−３６１Ｎ」、ポリアクリレート化合物）：０．５部
添加剤（ＢＡＳＦジャパン社製「ＬＲ９０００」）：５．７部
溶剤（プロピレングリコール１−モノメチルエーテル２−アセテート）：４１２部

Polymerization initiator ("Irgacure 907" manufactured by BASF Japan Ltd., 2-methyl-4 '-(methylthio) -2-morpholinopropiophenone): 2.6 parts Leveling agent ("BYK-361N" manufactured by BYK-Chemie, poly) Acrylate compound): 0.5 part Additive ("LR9000" manufactured by BASF Japan Ltd.): 5.7 parts Solvent (propylene glycol 1-monomethyl ether 2-acetate): 412 parts

(5-2) Preparation of laminate B having second retardation layer A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a base film, and the orientation obtained in (3-4) above was provided on the film. The film-forming composition was applied by the bar coating method and heated and dried in a drying oven at 90 ° C. for 1 minute.
The obtained dried coating film was subjected to UV irradiation treatment to form a second alignment film (AL2). The UV treatment was performed using the above UV irradiation device under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² .

The second retardation layer-forming composition obtained in (5-1) above was applied onto the formed second alignment film (AL2) by a bar coating method, and dried by heating in a drying oven at 90 ° C. for 1 minute. . By irradiating the obtained dried coating film with ultraviolet rays having a cumulative light amount of 1000 mJ / cm ² (365 nm standard) using a UV irradiation device in a nitrogen atmosphere, a second retardation layer (second retardation layer) is obtained. 70) was formed. The thickness of the obtained second retardation layer was 2.0 μm. The second retardation layer was a positive C plate (posiC) showing retardation in the thickness direction.
In this way, a laminate B composed of the second retardation layer (posiC) / second alignment film (AL2) / base material film (PET) was obtained.

(6) Fabrication of Optical Laminated Body It will be described with reference to FIGS. The alignment film is omitted in FIGS. 3 to 7.
In addition, when laminating all layers shown below, corona treatment (output 0.3 kW, speed 3 m / min, once) is performed on each laminating surface of the two layers to be laminated. (The same applies to other examples and comparative examples).

First, the release film A of the pressure-sensitive adhesive sheet A obtained in (2) above is peeled off, and the exposed pressure-sensitive adhesive layer is attached to the surface of the polarizer layer 30 of the laminate A obtained in (3) above. Thus, the laminated body shown in FIG. 3 was obtained. The adhesive layer of the adhesive sheet A corresponds to the second adhesive layer 40. In FIG. 3, reference numeral 41 indicates the release film B.
Next, the release film B was peeled off from the laminate shown in FIG. 3, and the first retardation layer (first retardation layer) of the laminate C obtained in (4) above was exposed on the exposed surface of the pressure-sensitive adhesive layer. 50) was laminated to obtain a laminate shown in FIG. In FIG. 4, reference numeral 51 indicates a base film (PET).

Next, a second pressure-sensitive adhesive sheet A was prepared, the release film A of the pressure-sensitive adhesive sheet A was peeled off, the base film was peeled off from the laminate shown in FIG. 4, and the exposed surfaces were bonded together. A laminate shown in FIG. 5 was obtained. The adhesive layer of the second adhesive sheet A corresponds to the third adhesive layer 60. In FIG. 5, reference numeral 41 indicates the release film B.
Next, the release film B was peeled off from the laminate shown in FIG. 5, and the second retardation layer (second retardation layer) of the laminate B obtained in (5) above was exposed on the exposed surface of the pressure-sensitive adhesive layer. 70) were laminated to obtain a laminate shown in FIG. The base material film (PET) of the laminate B corresponds to the supporting base material 80.

Next, the third pressure-sensitive adhesive sheet A is prepared, the release film A of the pressure-sensitive adhesive sheet A is peeled off, and the exposed pressure-sensitive adhesive layer is used as the thermoplastic resin film layer 90 (TAC film) of the laminate shown in FIG. ), And the laminated body shown in FIG. 7 was obtained. The adhesive layer of the third adhesive sheet A corresponds to the first adhesive layer 20. In FIG. 7, reference numeral 41 indicates the release film B.
Finally, the release film B is peeled from the laminate shown in FIG. 7, and the front plate 10 prepared in (1) above is attached to the exposed surface of the pressure-sensitive adhesive layer to obtain the same configuration as in FIG. An optical laminate having the above was obtained.

<Example 2>
An optical laminate was prepared according to the following procedure. This will be described with reference to FIGS. The alignment film is omitted in FIGS. 8 to 10.
First, the laminated body shown in FIG. 3 was obtained in the same manner as in Example 1. The pressure-sensitive adhesive layer included in this laminated body corresponds to the second pressure-sensitive adhesive layer 40.
Next, a laminated body C and a laminated body B were prepared in the same manner as in Example 1, and the first retardation layer side of the laminated body C and the second retardation layer side of the laminated body B were bonded with an ultraviolet curable adhesive ( The epoxy-based ultraviolet curable adhesive manufactured by ADEKA Co., Ltd., viscosity at 25 ° C .: 44 mPa · s) was used for bonding. Then, the laminated body B was irradiated with ultraviolet rays (UVB) having an integrated light amount (integrated amount of light irradiation intensity in the wavelength region of 280 to 320 nm) of about 250 mJ / cm ² (measurement machine: measured by UV Power Puck II manufactured by FusionUV). Irradiation was performed from the surface side to obtain the laminated body shown in FIG. The base film (PET) that the laminate B had in this laminate corresponds to the supporting substrate 80. In FIG. 8, reference numeral 61 indicates an adhesive layer (cured layer of an ultraviolet curable adhesive), and reference numeral 51 indicates a base film (PET) that the laminate C had.

Next, the release film B is peeled from the laminate shown in FIG. 3, the base film is peeled from the laminate shown in FIG. 8, the exposed surfaces are bonded together, and the laminate shown in FIG. Got
Next, a second pressure-sensitive adhesive sheet A is prepared, the release film A of the pressure-sensitive adhesive sheet A is peeled off, and the exposed pressure-sensitive adhesive layer is replaced with the thermoplastic resin film layer 90 (TAC film) of the laminate shown in FIG. ), And the laminated body shown in FIG. 10 was obtained. The adhesive layer of the second adhesive sheet A corresponds to the first adhesive layer 20. In FIG. 10, reference numeral 41 indicates the release film B.
Finally, the release film B was peeled off from the laminate shown in FIG. 10, and the same front plate 10 (total thickness: 30 μm) as that prepared in Example 1 was attached to the exposed surface of the adhesive layer. Then, an optical layered body having the same configuration as that of FIG. 2 except that the third adhesive layer 60 was replaced by the adhesive layer 61 was obtained.

<Example 3>
An optical layered body was obtained in the same manner as in Example 2 except that as the front plate 10, a polyimide film having a hard coat layer on both sides having a total thickness of 50 μm (tensile elastic modulus: 5.5 GPa) was used.

<Example 4>
An optical laminate was obtained in the same manner as in Example 1 except that as the front plate 10, a polyimide film (tensile elastic modulus: 5.6 GPa) having hard coat layers on both sides having an overall thickness of 70 μm was used.

<Example 5>
An optical laminate was obtained in the same manner as in Example 2 except that as the front plate 10, a polyimide film (tensile elastic modulus: 5.6 GPa) having hard coat layers on both sides having an overall thickness of 70 μm was used.

<Example 6>
(1) Preparation of adhesive sheet B An acrylic resin was obtained by reacting the following components at 55 ° C with stirring in a nitrogen atmosphere.
Butyl acrylate: 70 parts Methyl acrylate: 20 parts Acrylic acid: 1.0 parts Radical polymerization initiator (2,2′-azobisisobutyronitrile): 0.2 parts Solvent (ethyl acetate): 80 parts The resulting acrylic resin was mixed with 0.3 part of a crosslinking agent (“Coronate L” manufactured by Tosoh Corporation) and 0.5 part of a silane coupling agent (“X-12-981” manufactured by Shin-Etsu Silicon Co., Ltd.), and the whole was mixed. Ethyl acetate was added so that the solid content concentration was 10% to obtain an adhesive composition.
The obtained pressure-sensitive adhesive composition was applied to the release-treated surface of a release-treated polyethylene terephthalate film (release film B, thickness 38 μm) using an applicator so that the thickness after drying would be 25 μm. The coating layer was dried at 100 ° C for 1 minute to obtain a film having an adhesive layer. Then, on the exposed surface of the pressure-sensitive adhesive layer, another polyethylene terephthalate film (release film A, thickness 38 μm) subjected to release treatment was attached. Then, it was aged at a temperature of 23 ° C. and a relative humidity of 50% RH for 7 days.
In this way, a pressure-sensitive adhesive sheet B composed of release film A / pressure-sensitive adhesive layer / release film B was prepared.
The storage elastic modulus at 25 ° C. of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet B was 0.05 MPa.

(2) Preparation of Optical Laminate A polyimide film having a hard coat layer on both sides having a total thickness of 70 μm (tensile elastic modulus: 5.6 GPa) was used as the front plate 10, and the first pressure-sensitive adhesive layer was used. An optical layered body was obtained in the same manner as in Example 2 except that the pressure-sensitive adhesive sheet B used in (1) was used instead of the pressure-sensitive adhesive sheet A as the pressure-sensitive adhesive sheet used for laminating the 20 and the second pressure-sensitive adhesive layer 40. It was

<Example 7>
An optical laminate was obtained in the same manner as in Example 1 except that as the front plate 10, a polyimide film (tensile elastic modulus: 5.4 GPa) having hard coat layers on both sides having an overall thickness of 120 μm was used.

<Example 8>
An optical laminate was obtained in the same manner as in Example 2 except that as the front plate 10, a polyimide film having a hard coat layer on both sides and having a total thickness of 120 μm (tensile modulus: 5.4 GPa) was used.

<Example 9>
As the laminate A, a laminate having a polarizer layer 30 (thickness 8 μm) made of a stretched polyvinyl alcohol film on a cyclic polyolefin resin film (thickness 13 μm) was used in the same manner as in Example 1 except that FIG. An optical layered body having the same configuration as that of was obtained. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90.

The laminate A used in this example was manufactured by the following procedure.
A polyvinyl alcohol film having a thickness of 20 μm (average polymerization degree of about 2,400, saponification degree of 99.9 mol% or more) was uniaxially stretched by dry stretching to about 4.9 times. Further, the film was immersed in pure water at 60 ° C. for 1 minute while maintaining the tension. Next, the film was immersed for 60 seconds in an aqueous solution of 28 ° C. in which the mass ratio of iodine / potassium iodide / water was 0.05 / 5/100. Then, the film was immersed for 300 seconds in an aqueous solution of 72 ° C. in which the mass ratio of potassium iodide / boric acid / water was 8.5 / 8.5 / 100. Subsequently, the film was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizer (polarizer layer 30) having a thickness of 8 μm in which iodine was adsorbed and oriented on the polyvinyl alcohol film.
Next, the polarizer and the cyclic olefin-based resin film (thickness 13 μm) were bonded together via an aqueous adhesive to obtain a laminate A which is a polarizing plate.

<Example 10>
Third example was repeated in the same manner as in Example 5 except that a laminated body having a polarizer layer 30 (thickness 8 μm) made of a stretched polyvinyl alcohol film on a cyclic polyolefin resin film (thickness 13 μm) was used as the laminated body A. An optical layered body having the same configuration as that of FIG. 2 except that an adhesive layer 61 was provided instead of the adhesive layer 60 was obtained. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90.
The procedure for producing the laminated body A used in this example is the same as that in the ninth example.

<Comparative Example 1>
In the same manner as in Example 1 except that the pressure-sensitive adhesive sheet B was used instead of the pressure-sensitive adhesive sheet A as the pressure-sensitive adhesive sheet used for laminating the first pressure-sensitive adhesive layer 20, the second pressure-sensitive adhesive layer 40, and the third pressure-sensitive adhesive layer 60. An optical laminate was obtained.

<Comparative example 2>
An optical laminate was obtained in the same manner as in Example 2 except that the pressure-sensitive adhesive sheet B was used instead of the pressure-sensitive adhesive sheet A as the pressure-sensitive adhesive sheet used for laminating the first pressure-sensitive adhesive layer 20 and the second pressure-sensitive adhesive layer 40.

<Comparative example 3>
An optical laminate was obtained in the same manner as in Comparative Example 2 except that as the front plate 10, a polyimide film having a hard coat layer on both sides and having an overall thickness of 50 μm (tensile elastic modulus: 5.5 GPa) was used.

<Comparative example 4>
An optical laminate was obtained in the same manner as in Comparative Example 1 except that a polyimide film having a hard coat layer on both sides (tensile elastic modulus: 5.6 GPa) having a total thickness of 70 μm was used as the front plate 10.

Table 1 shows the thickness T of the front plate, the creep value C of each pressure-sensitive adhesive layer, and the T / C _total of the optical laminates produced in Examples and Comparative Examples.

(Evaluation test)
[A] Evaluation of Reflected Reflected Image The optical laminate was placed in a dark room with the front plate side facing up, and the fluorescent lamp consisting of two linear fluorescent tubes on the indoor ceiling was turned on. The image of the fluorescent tube reflected on the surface of the front plate was visually observed, and the degree of suppression of distortion of the image was evaluated according to the following evaluation criteria. The results are shown in Table 1.
A: The fluorescent tube is completely or almost linear.
B: The fluorescent tube is slightly distorted.
C: The fluorescent tube is significantly distorted.

[B] Evaluation of Flexibility The optical layered body was subjected to a flexibility test according to the following procedure. FIG. 11 is a schematic diagram illustrating the method of the flexibility test.
A bending device (“STS-VRT-500” manufactured by Science Town) including two stages 501 and 502 was prepared, and the optical laminated body 100 was placed on the stages 501 and 502 (FIG. 11A). The distance (gap) C between the two stages 501 and 502 was set to 2 mm (1.0 R). The stages 501 and 502 can swing around a gap (gap) C between the two stages, and the two stages 501 and 502 initially form the same plane. The two stages 501 and 502 are rotated 90 degrees upward with the position P1 and the position P2 being the center of the rotation axis to close the two stages 501 and 502 (FIG. 11B) and to open the stages 501 and 502 again. Defined as one bend. This operation was repeated, and the number of times of bending until the first crack was generated in the optical laminate 100 was counted. The evaluation criteria are as follows. The results are shown in Table 1.
AA (extremely good): 100,000 times or more A (good): 50,000 times or more but less than 100,000 times B (usable): 30,000 times or more but less than 50,000 times C (somewhat inferior): 10,000 times or more than 30,000 times Less than D (inferior): less than 10,000 times

  1, 2 Optical layered product, 10 Front plate, 20 First pressure-sensitive adhesive layer, 30 Polarizer layer, 40 Second pressure-sensitive adhesive layer, 41 Release film B, 50 First retardation layer, 51 Base film, 60 Third Adhesive layer, 61 Adhesive layer, 70 2nd phase difference layer, 80 Supporting substrate, 90 Thermoplastic resin film layer, 100 Optical laminated body, 501,502 Stage.

Claims (7)

The front plate, the pressure-sensitive adhesive layer (A), the polarizer layer, and the n layer [n represents any integer of 0 or more. ] The pressure-sensitive adhesive layer (B) and a supporting base material in this order,
Formula (1) below:
0.2 ≦ T / C _total (1)
[In Formula (1),
T represents the thickness [μm] of the front plate.
C _total represents the total creep value C [%] at 25 ° C. of each pressure-sensitive adhesive layer arranged between the front plate and the supporting base material. ]
An optical laminated body that satisfies the requirements. Formula (2) below:
T / C _total ≦ 1.2 (2)
[In the formula (2), T and C _total represent the same meaning as described above. ]
The optical laminate according to claim 1, which further satisfies   The optical laminate according to claim 1 or 2, wherein n is an integer of 1 or more.   The optical laminate according to claim 1, further comprising one or more retardation layers arranged between the polarizer layer and the supporting base material.   The optical layered body according to claim 4, wherein the retardation layer contains a cured product of a polymerizable liquid crystal compound.   The optical layered body according to any one of claims 1 to 5, wherein the polarizer layer contains a cured product of a polymerizable liquid crystal compound.   A display device comprising the optical laminate according to claim 1.

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