JP6797163B2 - Optical laminate and display device - Google Patents

Description

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

As various display devices such as a liquid crystal display device and an organic electroluminescence (EL) display device, 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, in International Publication No. 2017/20228 (Patent Document 1), a laminate including a resin film having a predetermined surface roughness and an adhesive layer arranged on one surface of the resin film and having a predetermined loss tangent is described above. It is stated that it applies to the front plate.

International Publication No. 2017/20228

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

An object of the present invention is to provide an optical laminate including a front plate and one or more pressure-sensitive adhesive layers, the optical laminate in which distortion of a reflected image reflected on the surface of the front plate is suppressed, and a display device including the same. To do.

The present invention provides an optical laminate display device shown below.
[1] The front plate, the pressure-sensitive adhesive layer (A), the polarizer layer, and the n-layer [n represents any integer of 0 or more. ], Which is an optical laminate containing the pressure-sensitive adhesive layer (B) and the supporting base material in this order.
The following formula (1):
0.2 ≤ T / C _total (1)
[In equation (1),
T represents the thickness [μm] of the front plate.
C _total represents the sum of the creep values C [%] at 25 ° C. of each pressure-sensitive adhesive layer arranged between the front plate and the supporting base material. ]
An optical laminate that satisfies.
[2] The following equation (2):
T / C _total ≤ 1.2 (2)
[In the formula (2), T and C _total have the same meanings as described above. ]
The optical laminate according to [1], which further satisfies the above.
[3] The optical laminate according to [1] or [2], wherein n is an integer of 1 or more.
[4] The optical laminate according to any one of [1] to [3], further including one or more retardation layers arranged between the polarizer layer and the supporting base material.
[5] The optical laminate according to [4], wherein the retardation layer contains a cured product of a polymerizable liquid crystal compound.
[6] The optical laminate 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 laminate according to any one of [1] to [6].

It is possible to provide an optical laminate including a front plate and one or more pressure-sensitive adhesive layers, the optical laminate in which distortion of a reflected image reflected on the surface of the front plate is suppressed, and a display device including the same.

It is the schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention. It is schematic cross-sectional view which shows another example of the optical laminated body which concerns on this invention. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 1. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 1. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 1. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 1. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 1. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 2. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 2. FIG. It is schematic cross-sectional view explaining the manufacturing method of the optical laminate in Example 2. FIG. It is the schematic 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 drawings below, the scale is appropriately adjusted to make it easier to understand each component, and the scale of each component shown in the drawings does not necessarily match the scale of the actual component.

In the present specification, the meanings or definitions of the following terms are as follows.
The "optical laminate" is a laminate applied to an optical device such as a display device, and is a laminate composed of two or more layers. The two or more layers constituting the optical laminate may be a coating layer or the like formed by independently coating a plate, a sheet, a film, or a coating liquid for forming a layer. Examples of the display device include an image display device such as a liquid crystal display device and an organic EL display device.
The optical laminate according to the present invention represents a front plate, an adhesive layer (A), a polarizer layer, and n layers [n is an integer of 0 or more. ] The pressure-sensitive adhesive layer (B) and the supporting base material are included in this order.
In the optical laminate according to the present invention, a display element (liquid crystal cell, organic EL display element, inorganic EL 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 visual recognition side) It is arranged on the visual side of the plasma display element, electric field radiation type display element, etc.).

The "adhesive layer" refers to a layer composed of an adhesive or a layer obtained by subjecting the layer to some kind of treatment.
The "adhesive" is also called a pressure-sensitive adhesive.
As used herein, the term "adhesive" refers to an adhesive other than an adhesive (pressure sensitive adhesive) and is clearly distinguished from an adhesive.
The "adhesive layer" refers to a layer made of an adhesive or a layer obtained by subjecting the layer to some kind of treatment.
The pressure-sensitive adhesive layer and the adhesive layer can be clearly distinguished from each other in terms of physical properties. For example, taking the storage elastic modulus as a physical property, the pressure-sensitive adhesive layer generally 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 pressure-sensitive adhesive layer (A) refers to a pressure-sensitive adhesive layer arranged between the front plate and the polarizer layer. The optical laminate can include one layer or two or more pressure-sensitive adhesive layers as the pressure-sensitive adhesive layer (A), but is preferably one layer.
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 laminate may not include the pressure-sensitive adhesive layer (B), or may include one layer or two or more pressure-sensitive adhesive layers as the pressure-sensitive adhesive layer (B).

The "front plate" refers to a member arranged on the outermost surface (the outermost surface on the visual 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.

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

"Bendable" means that when the optical laminate is bent so that the radius of curvature of the inner surface of the optical laminate is 1 mm in at least one direction in the plane, the optical laminate is bent without causing cracks. It means that it is possible.
When the optical laminate is repeatedly bent so that the radius of curvature of the inner surface of the optical laminate is 1 mm in at least one direction in the plane, cracks are preferably generated even if the number of bends is 10,000. Absent.

<Optical laminate>
[1] Outline of Shape and Layer Structure of Optical Laminate 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 the supporting base material 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 an integer of 1 or more, more preferably an integer of 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 (intervening other layers).

The optical laminate 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 the pressure-sensitive adhesive layer or the adhesive layer.

The optical laminate can include layers other than those described above. The other layers are arranged, for example, between the pressure-sensitive adhesive layer (A) and the polarizer layer, between the polarizer layer and the supporting substrate, and outside the supporting substrate (the side opposite to the polarizer layer side). Can be done.
For example, the optical laminate can include a thermoplastic resin film layer disposed between the pressure-sensitive adhesive layer (A) and the polarizer layer. For example, the optical laminate may include a thermoplastic resin film layer that is laminated on the surface of the polarizer layer on the front plate side and / or the surface on the support substrate side, for example, via an adhesive layer. Further, the optical laminate may incorporate a base film to which the coating liquid is applied when the layer is formed by applying the coating liquid together with the above layer.
For example, the optical laminate can include an adhesive layer (C) that is located outside 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, the application of the optical laminate, etc., but is, for example, 50 μm or more and 1000 μm or less, preferably 100 μm or more and 500 μm or less, more preferably. Is 100 μm or more and 300 μm or less.

The plan view shape of the optical laminate may be, for example, a rectangular shape, preferably a rectangular shape having a long side and a short side, and more preferably a rectangle. When the plan view shape of the optical laminate is rectangular, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, 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 laminate is a square shape, the length of each side in each layer constituting the optical laminate may be the same as each other. Each layer constituting the optical laminate may have corners R-processed, end portions may be notched, 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 laminate 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, and a second adhesive layer 40 which is an adhesive layer (B). The first retardation layer 50, the third pressure-sensitive adhesive layer 60 which is the pressure-sensitive adhesive layer (B), the second retardation layer 70, and the support base material 80 are provided in this order.
In the optical laminate 1, an adhesive layer may be used instead of the second adhesive layer 40. In the optical laminate 1, an adhesive layer may be used instead of the third adhesive layer 60. In the optical laminate 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 cross-sectional view showing another example of the optical laminate according to the present invention. The optical laminate 2 shown in FIG. 2 is the same layer as the optical laminate 1 shown in FIG. 1 except that it has a thermoplastic resin film layer 90 between the first pressure-sensitive adhesive layer 20 and the polarizer layer 30. It has a configuration.
In the optical laminate 2, an adhesive layer may be used instead of the second adhesive layer 40. In the optical laminate 2, an adhesive layer may be used instead of the third adhesive layer 60. In the optical laminate 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] Regarding the above formulas (1) and (2) The optical laminate according to the present invention satisfies the above formula (1). This makes it possible to suppress distortion of the reflected image reflected on the surface of the front plate 10.
The present inventors have conducted intensive studies 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 optics of the front plate arranged on the outermost side of the optical laminate. When it is related to the strain characteristics when stress is applied to the pressure-sensitive adhesive layer contained in the laminate and when the T / C _total in the above formula (1) is equal to or more than a predetermined value, the distortion of the reflected image is effective. It was found that it can be suppressed.
From the viewpoint of suppressing distortion of the reflected image, the 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 increasing the flexibility of the optical laminate and the display device including the optical laminate, the optical laminate according to the present invention preferably satisfies the above formula (2). From the viewpoint of increasing the flexibility of the optical laminate and the display device including the optical laminate, the T / C _total in the above formula (2) is more preferably 1.18 or less, still more preferably 1.15 or less, and even more so. It is preferably 1.10 or less.

As described above, when the optical laminate is repeatedly bent so that the radius of curvature of the inner surface of the optical laminate is 1 mm in at least one direction in the plane, the number of bends is preferably 10,000. No cracks occur.
When the optical laminate is repeatedly bent so that the radius of curvature of the inner surface of the optical laminate is 1 mm in at least one direction in the plane, more preferably, the optical laminate cracks even if the number of bends is about 50,000. Is not generated, more preferably, cracks are not generated even if the number of bendings is about 80,000 times, and even more preferably, cracks are not generated even if the number of bendings is about 100,000 times.
It is preferable that the number of times of bending of the optical laminate is in the above range, at least in one direction in the plane and in a direction orthogonal to the direction, so that cracks do not occur when the optical laminate is repeatedly bent.
A display device to which an optical laminate having good flexibility is applied can be used as a flexible display capable of bending, bending, winding, or the like.

The C _total in the formulas (1) and (2) represents the sum of the creep values 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 support base material 80 refers to the pressure-sensitive adhesive layer (A) or the pressure-sensitive adhesive layer corresponding to the pressure-sensitive adhesive layer (B), and is located outside the support base material 80. The pressure-sensitive adhesive layer (C) to be arranged is not included.
The creep value C of each pressure-sensitive adhesive layer at 25 ° C. is measured according to the method described in the section of Examples described later.

[4] Front plate The front plate 10 is preferably a plate-like body capable of transmitting light. The 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-like body (for example, a glass plate, a glass film, etc.) and a resin plate-like 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 optical laminate, a resin plate-like body such as a resin film is preferable. Further, when a glass plate-like body is used, the problem of distortion of the reflected image is unlikely to occur in the first place, although it depends on the thickness thereof.

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

The front plate 10 may be a film having a hard coat layer provided on at least one surface of the base film to further improve the hardness. As the base film, the above-mentioned resin film can be used.
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 scratchability 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, epoxy resin and the like. The hard coat layer may contain additives to improve strength. Additives are not limited, and examples thereof include inorganic fine particles, organic fine particles, and mixtures thereof.

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

The thickness T of the front plate 10 is appropriately selected so as to satisfy the above formula (1), preferably further the above formula (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 distortion of the reflected image and flexibility of the optical laminate and the display device including the same. More preferably, it may be 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 further 40 μm or more and 100 μm or less.

From the viewpoint of suppressing distortion of the reflected image and the flexibility of the optical laminate and the display device including the optical laminate, the tensile elastic modulus of the front plate 10 is preferably 2.0 GPa or more and 10.0 GPa or less, and more preferably 3. It is 0.0 GPa or more and 9 GPa or less, and more preferably 4.0 GPa or more and 8.0 GPa or less. The tensile elastic 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 laminate can include one layer or two or more pressure-sensitive adhesive layers as the pressure-sensitive adhesive layer (A), but is preferably one layer.

The pressure-sensitive adhesive layer (A) can be composed of a pressure-sensitive adhesive composition containing a resin as a main component, such as (meth) acrylic type, rubber type, urethane type, ester type, silicone type, and polyvinyl ether type. Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer 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, and hexyl (meth) acrylate. (Meta) acrylics such as octyl (meth) acrylate, lauryl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate A polymer or copolymer having one or more kinds of acid esters as monomers is preferably used.
It is preferable that the base polymer is copolymerized with a polar monomer. 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-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. 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 active energy rays such as ultraviolet rays and electron beams, and has adhesiveness even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having the property of being able to adhere to an adherend such as, etc., and being cured by irradiation with active energy rays to adjust the adhesion force and the like.
The active energy ray-curable pressure-sensitive adhesive composition is preferably an ultraviolet-curable type. 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 cross-linking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer, or the like may be contained.
The active energy ray-polymerizable compound is, for example, a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; obtained by reacting two or more kinds of functional group-containing compounds, and at least in the molecule. Examples thereof include (meth) acrylic 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 the base polymer, pressure-sensitive imparting agents, and fillers (metal powders and other inorganic powders). Etc.), antioxidants, UV absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and other additives can be included.

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

The creep value C of the first pressure-sensitive adhesive layer 20 (the pressure-sensitive adhesive layer (A)) is, for example, its thickness, elastic modulus, molecular weight of the base polymer, degree of curing when an active energy ray-curable pressure-sensitive adhesive composition is used, and the like. It can be controlled by adjusting.
The creep value C of the first pressure-sensitive adhesive layer 20 (the 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. May be good.

From the viewpoint of suppressing the flexibility of the optical laminate and the display device including the optical laminate and the distortion of the reflected image, the storage elastic modulus of the first adhesive layer 20 (adhesive layer (A)) at 25 ° C. 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, 0.10 MPa or more, or 0.50 MPa or more.
The storage elastic modulus of the first adhesive layer 20 (adhesive layer (A)) depends on the selection of the material forming the first adhesive layer 20 (adhesive layer (A)) and the thickness of the first adhesive layer 20. , The production conditions of the first pressure-sensitive adhesive layer 20, or a combination thereof can be adjusted.
The storage elastic modulus of the pressure-sensitive adhesive layer at 25 ° C. is measured according to the method described in the section of Examples described later.

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 the layers via the first pressure-sensitive adhesive layer 20 and control of 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 an absorption anisotropy is adsorbed, a layer formed by applying a dye having an absorption anisotropy and curing the layer, and the like.
Examples of the dye having absorption anisotropy include a dichroic dye. Specifically, as the dichroic dye, iodine or a dichroic organic dye is used. For dichroic organic dyes, C.I. I. Included are dichroic direct dyes composed of disuazo compounds such as DIRECT RED 39 and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo.
As the polarizer layer formed by applying and curing a dye having absorption anisotropy, a composition containing a dichroic dye having liquid crystal properties 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 by the above-mentioned.
A polarizing layer formed by applying and curing a dye having absorption anisotropy is preferable because there is no limitation in the bending direction as compared with a stretched film or a stretched layer having a dye having absorption anisotropy adsorbed. Therefore, in order to obtain an optical laminate in which the number of times of bending that does not cause cracks when the above-mentioned repeated bending is performed is in the above range at least in one direction in the plane, in a direction orthogonal to the direction, and in all directions in the plane. Then, as the polarizer layer 30, it is preferable to apply and cure a dye having absorption anisotropy to use the layer.

[6-1] Stretched film or polarized layer as a stretched layer The polarizing layer 30 which is a stretched film on 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 a 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 produced through a step 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 further 10 μm or less.

The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based 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 other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based 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 on which a dye having absorption anisotropy is adsorbed, is usually a step of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, and uniaxially stretching the obtained laminated film. 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, the dichroic dye is adsorbed. The film can be produced through a step of treating the film with an aqueous boric acid solution and a step of washing the film with water after the treatment with the aqueous boric acid 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 stretched film or the polarizer layer 30 which is a stretched layer may be incorporated into the optical laminate in a form in which a thermoplastic resin film is bonded 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 (polypropylene resin, etc.), a cyclic polyolefin resin (norbornen resin, etc.); a cellulose resin such as triacetyl cellulose; polyethylene terephthalate, polyethylene na. A film made of a polyester resin such as phthalate or polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin; or a mixture thereof can be used.
From the viewpoint of thinning, the thickness of the thermoplastic resin film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, still more preferably 60 μm or less. Yes, it is usually 5 μm or more, preferably 20 μm or more.
The thermoplastic resin film may or may not have a phase difference.
The thermoplastic resin film can be attached to the polarizer layer 30 by using, for example, an adhesive layer.

[6-2] Polarizer layer formed by applying and curing a dye having absorption anisotropy The polarizing layer layer formed by applying and curing a dye having absorption anisotropy includes a liquid crystal property and a polymerizable dichroism. Polymerization of layers and 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 thereof include a polarizer layer containing a cured product of a dichroic 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 formed by applying and curing a dye having absorption anisotropy may be incorporated into an optical laminate in a form in which a thermoplastic resin film is bonded to one side or both sides thereof. As the thermoplastic resin film, the same one as the thermoplastic resin film that can be used for the stretched film or the polarizer layer that is the stretched layer can be used.
The thermoplastic resin film can be attached to the polarizer layer 30 by using, for example, an adhesive layer.
Specific examples of the polarizer layer 30 formed by applying and curing a dye having absorption anisotropy include those described in JP-A-2012-33249.

The thickness of the polarizer layer 30 obtained by applying 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 present invention is not limited to these embodiments, and the optical laminate may not include the pressure-sensitive adhesive layer (B), and the pressure-sensitive adhesive layer (B) may include one or more pressure-sensitive adhesive layers. It may be included. The number of the pressure-sensitive adhesive layer (B) is preferably 1 or more, more preferably 1 or more and 3 or less, and further preferably 1 or 2.

For the composition and compounding components of the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer (B), the type of the pressure-sensitive adhesive composition (whether it is an active energy ray-curable type or a heat-curable type, etc.), and the pressure-sensitive adhesive layer (B). Additives that can be blended, a method for producing the pressure-sensitive adhesive layer (B), the thickness of the pressure-sensitive adhesive layer (B), the creep value C and its range of the pressure-sensitive adhesive layer (B) at 25 ° C., and the pressure-sensitive adhesive layer (B). For the storage elasticity at 25 ° C. and its range, the description of the pressure-sensitive adhesive layer (A) is cited.
One layer or two or more layers of the pressure-sensitive adhesive layer 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., and the like. It may be, or it 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 terms of thickness, creep value C at 25 ° C., storage elastic modulus at 25 ° C., and the like. It may be, or it may be different.

[8] Support base material The support base material 80 is preferably a plate-like body capable of transmitting light. The support 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.
The supporting base material 80 includes, for example, a glass plate-like body (for example, a glass plate, a glass film, etc.) and a resin plate-like body (for example, a resin plate, a resin sheet, a resin film, etc.), similarly to the front plate 10. Etc.).
Among the above, from the viewpoint of flexibility of the optical laminate and the display device including the optical laminate, a resin plate-like body such as a resin film is preferable. As for a specific example of the thermoplastic resin constituting the resin plate-like body such as a resin film, the description of the front plate 10 is cited. The thermoplastic resin is preferably a cellulose-based resin, a (meth) acrylic-based resin, a cyclic polyolefin-based resin, a polyester-based resin, a polycarbonate-based resin, or the like.

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

[9] Phase Difference Layer The optical laminate may further include one layer or two or more retardation layers. The retardation layer is usually arranged between the polarizer layer 30 and the support base material 80. The retardation layer can be laminated on another layer (including another retardation layer) via the pressure-sensitive adhesive layer or the 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, a positive C plate, and the like.
The retardation layer may be, for example, a retardation film that can be formed from the above-mentioned thermoplastic resin film, or includes a layer obtained 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 above-mentioned thermoplastic resin film. The thickness of the retardation layer obtained 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 to a base 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 into the optical laminate in the form of having an alignment layer and / or a base film. The support base material 80 may be a base film to which the above composition is applied.

As described above, an adhesive layer may be used or an adhesive layer may be used for laminating the retardation layer. This pressure-sensitive adhesive layer corresponds to the pressure-sensitive 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, a water-based two-component urethane-based emulsion adhesive, and the like.

The active energy ray-curable adhesive refers to an adhesive that cures by irradiating with active energy rays such as ultraviolet rays, and includes, for example, a polymerizable compound and a photopolymerization initiator, and a photoreactive resin. Examples thereof include those containing a binder resin and a photoreactive cross-linking 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 substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals when irradiated with active energy rays such as ultraviolet rays. As the active energy ray-curable adhesive containing a polymerizable compound and a photopolymerization initiator, those containing a photocurable epoxy monomer and a photocationic polymerization initiator can be preferably used.

[10] Method for Producing Optical Laminate The optical laminate can be produced by a method including a step of laminating layers constituting the optical laminate via an adhesive layer or an adhesive layer. When the layers are bonded to each other via an adhesive layer or an adhesive layer, one or both of the bonded surfaces should be subjected to a surface activation treatment such as a corona treatment in order to improve the adhesion. Is preferable.
The polarizer layer and the retardation layer can be formed directly on the thermoplastic resin film or the base film or through the alignment film, and the thermoplastic resin film or the base film is incorporated into the optical laminate. Alternatively, it may not be separated from the polarizer layer or the retardation layer and become a component of the optical laminate.
A specific method for producing an optical laminate can be understood by referring to the section of Examples described later.

<Display device>
The display device according to the present invention includes the above-mentioned optical laminate according to the present invention. The display device is not particularly limited, and examples thereof include an image display device 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 laminate is suitable for a flexible display device that can be bent or bent.
In the display device, the optical laminate is arranged on the visible side of the display element of the display device with the front plate facing the outside (the side opposite to the display element side, that is, the visual recognition side).

The display device according to the present invention can be used as a mobile device such as a smartphone or tablet, a television, a digital photo frame, an electronic signboard, a measuring instrument or an instrument, an office device, a medical device, a computer device, or the like.
The display device according to the present invention is excellent in 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 representing the content or the amount used are based on mass unless otherwise specified.

The measurement method for the following items was as follows.
[A] Layer thickness 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 the pressure-sensitive adhesive layer The pressure-sensitive adhesive layer samples stacked so as to have a thickness of 150 μm were measured at a temperature of 25 ° C. by a torsional shear method using a rheometer (“MCR-301” manufactured by Antonio Parr). The storage elastic modulus (G') [MPa] was measured under the condition of a frequency of 1 Hz.

[C] Creep value C of the adhesive layer
A rheometer (“MCR-300” manufactured by Antonio Parr) was used 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) at a temperature of 25. A time-strain curve was obtained when a torque of 1200 μNm was applied to the sample at ° C., 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 the 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 of FIG. 2 was produced according to the following procedure.
(1) Preparation of front plate As the front plate 10, a polyimide film having hard coat layers on both sides (overall 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 in 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 1.0 part of the cross-linking agent (“Coronate L” manufactured by Toso Co., Ltd.) and 0.5 part of the silane coupling agent (“X-12-981” manufactured by Shin-Etsu Silicon Co., Ltd.) are mixed with the acrylic resin. Acrylic acid acetate was added so that the solid content concentration became 10% to obtain a pressure-sensitive adhesive composition.
The obtained pressure-sensitive adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (release film B, thickness 38 μm) using an applicator so that the thickness after drying was 5 μm. The coating layer was dried at 100 ° C. for 1 minute to obtain a film having an adhesive layer. Then, another polyethylene terephthalate film (release film A, thickness 38 μm) that had been released from the mold was attached onto the exposed surface of the pressure-sensitive adhesive layer. Then, it was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 50% RH.
In this way, the pressure-sensitive adhesive sheet A composed of the release film A / the pressure-sensitive adhesive layer / the release film B was produced.
The storage elastic modulus of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet A at 25 ° C. was 1.00 MPa.

(3) Preparation of Laminated A with Polarizer Layer (3-1) Preparation of Polymerizable Liquid Crystal Compound A polymerizable liquid crystal compound represented by the following formula (1-6) (hereinafter, "Compound (1-6)"". (Also also referred to as) and a polymerizable liquid crystal compound represented by the following formula (1-7) (hereinafter, also referred to as “compound (1-7)”) are referred to as 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 the dichroic dye, in the examples of JP2013-101328 represented by the following formulas (2-1a), (2-1b) and (2-3a). The above-mentioned azo dye was prepared.

(3-3) Preparation of Composition for Forming a Polarizer Layer 75 parts of compound (1-6) and 25 parts of compound (1-7), which are polymerizable liquid crystal compounds, formula (2-1a) which is a bicolor dye. , 2.5 parts each of the azo dyes represented by (2-1b) and (2-3a), 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one as a polymerization initiator. (BASF Japan Co., Ltd. "Irgacure 369") 6 parts and 1.2 parts of a polyacrylate compound as a leveling agent (BYK-Chemie Co., Ltd. "BYK-361N") were mixed with 400 parts of a solvent toluene. A composition for forming a polarizer layer was prepared by stirring the mixture at 80 ° C. for 1 hour.

(3-4) Preparation of Alignment Film Forming Composition A polymer having a photoreactive group consisting of the following structural units is dissolved in cyclopentanone so as to have a concentration of 5% to prepare an alignment film forming composition. Prepared.

(3-5) Preparation of Laminated Body A Having a Polarizer Layer On a triacetyl cellulose (TAC) film (thickness 25 μm), the composition for forming an alignment film obtained in (3-4) above was subjected to a bar coating method. It was applied and dried by heating in a drying oven at 80 ° C. for 1 minute.
The obtained dry coating film was subjected to polarized UV irradiation treatment to form a first alignment film (AL1). In the polarized UV treatment, the light emitted from the UV irradiation device (“SPOT CURE SP-7” manufactured by Ushio, Inc.) is transmitted through a wire grid (“UIS-27132 ##” manufactured by Ushio, Inc.). This 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.

The composition for forming a polarizer layer obtained in (3-3) above is applied onto the formed first alignment film (AL1) 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 dry coating film with ultraviolet rays at an integrated light amount of 1200 mJ / cm ² (365 nm standard) using the above 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 / the first alignment film (AL1) / the thermoplastic resin film layer 90 (TAC film) was obtained.

(4) Preparation of Laminated Body C Having First Phase Difference Layer (4-1) Preparation of Composition for Forming First Phase Difference Layer Each component shown below is mixed, and the obtained mixture is mixed at 80 ° C. for 1 hour. By stirring, a composition for forming a first retardation layer was prepared.
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: 20 parts represented by the following formula

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 (BASF Japan "Irgacure 369", 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one): 6-part leveling agent (BYK-Chemie "BYK-361N") , Polyacrylate compound): 0.1 parts Solvent (cyclopentanone): 400 parts

(4-2) Preparation of Laminated Body C Having First Phase Difference 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 obtained on the film. The film-forming composition was applied by the bar coating method and dried by heating in a drying oven at 80 ° C. for 1 minute.
The obtained dry coating film was subjected to polarized UV irradiation treatment to form a third alignment film (AL3). The polarized UV treatment was carried out under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² using the above UV irradiation device. Further, the polarization direction of the polarized UV was set to 45 ° with respect to the absorption axis of the polarizer layer 30.

The composition for forming the first retardation layer obtained in (4-1) above was applied onto the formed third alignment film (AL3) by the bar coating method, and dried by heating in a drying oven at 120 ° C. for 1 minute. After that, it was cooled to room temperature. The obtained dry coating film is irradiated with ultraviolet rays having an integrated light intensity of 1000 mJ / cm ² (365 nm standard) under a nitrogen atmosphere using the above UV irradiation device to obtain a 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 a first retardation layer (QWP) / a third alignment film (AL3) / a base film (PET) was obtained.

(5) Preparation of Laminated Body B Having Second Phase Difference Layer (5-1) Preparation of Composition for Forming Second Phase Difference Layer Each component shown below was mixed, and the obtained mixture was mixed at 80 ° C. for 1 hour. A composition for forming a 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 (BASF Japan "Irgacure 907", 2-methyl-4'-(methylthio) -2-morpholinopropiophenone): 2.6 parts Leveling agent (BYK-Chemie "BYK-361N", poly Acrylate compound): 0.5 parts Additive (“LR9000” manufactured by BASF Japan Ltd.): 5.7 parts Solvent (propylene glycol 1-monomethyl ether 2-acetate): 412 parts

(5-2) Preparation of Laminated Body B Having a Second Phase Difference 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 obtained on the film. The film-forming composition was applied by the bar coating method and dried by heating in a drying oven at 90 ° C. for 1 minute.
The obtained dry coating film was subjected to UV irradiation treatment to form a second alignment film (AL2). The UV treatment was carried out under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² using the above UV irradiation device.

The composition for forming the second retardation layer obtained in (5-1) above was applied onto the formed second alignment film (AL2) by the bar coating method, and dried by heating in a drying oven at 90 ° C. for 1 minute. .. The obtained dry coating film is irradiated with ultraviolet rays having an integrated light intensity of 1000 mJ / cm ² (365 nm standard) under a nitrogen atmosphere using the above UV irradiation device to obtain a second retardation layer (second retardation layer). 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 a phase difference in the thickness direction.
In this way, a laminate B composed of a second retardation layer (posiC) / a second alignment film (AL2) / a base film (PET) was obtained.

(6) Preparation of Optical Laminated Body This will be described with reference to FIGS. 3 to 7. The alignment film is omitted in FIGS. 3 to 7.
In addition, in the bonding of all the layers shown below, corona treatment (output 0.3 kW, speed 3 m / min, once) is performed on the bonded surfaces of the two layers to be bonded, and then the bonding is performed. (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 bonded to the surface of the polarizer layer 30 of the laminate A obtained in (3) above. The laminate shown in FIG. 3 was obtained. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet A corresponds to the second pressure-sensitive adhesive layer 40. Reference numeral 41 in FIG. 3 indicates a release film B.
Next, the release film B is 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 is placed on the surface of the exposed pressure-sensitive adhesive layer. 50) was laminated to obtain the laminate shown in FIG. In FIG. 4, reference numeral 51 indicates a base film (PET).

Next, a second adhesive sheet A is prepared, the release film A of the adhesive sheet A is peeled off, the base film is peeled off from the laminate shown in FIG. 4, and the exposed surfaces are bonded to each other. , The laminate shown in FIG. 5 was obtained. The pressure-sensitive adhesive layer of the second pressure-sensitive adhesive sheet A corresponds to the third pressure-sensitive adhesive layer 60. Reference numeral 41 in FIG. 5 indicates a release film B.
Next, the release film B is 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 is placed on the surface of the exposed pressure-sensitive adhesive layer. 70) was bonded to obtain a laminate shown in FIG. The base film (PET) of the laminate B corresponds to the support base material 80.

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

<Example 2>
An optical laminate was prepared according to the following procedure. This will be described with reference to FIGS. 8 to 10. The alignment film is omitted in FIGS. 8 to 10.
First, the laminate shown in FIG. 3 was obtained in the same manner as in Example 1. The pressure-sensitive adhesive layer contained in this laminate corresponds to the second pressure-sensitive adhesive layer 40.
Next, the laminate C and the laminate B are produced in the same manner as in Example 1, and the first retardation layer side of the laminate C and the second retardation layer side of the laminate B are bonded with an ultraviolet curable adhesive ( Epoxy-based ultraviolet curable adhesive manufactured by ADEKA Corporation, viscosity at 25 ° C.: 44 mPa · s) was used for bonding. After that, ultraviolet rays (UVB) having an integrated light amount (integrated amount of light irradiation intensity in a wavelength region of 280 to 320 nm) of about 250 mJ / cm ² (measuring machine: measured by UV Power Pack II manufactured by Fusion UV) are laminated B. Irradiation was performed from the surface side to obtain a laminate shown in FIG. The base film (PET) contained in the laminated body B in this laminated body corresponds to the supporting base material 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) contained in the laminate C.

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, and the exposed surfaces are bonded to each other, and the laminate shown in FIG. 9 is attached. 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 used as the thermoplastic resin film layer 90 (TAC film) of the laminate shown in FIG. ) To obtain the laminate shown in FIG. The pressure-sensitive adhesive layer of the second pressure-sensitive adhesive sheet A corresponds to the first pressure-sensitive adhesive layer 20. Reference numeral 41 in FIG. 10 indicates the release film B.
Finally, the release film B is peeled off from the laminate shown in FIG. 10, and the same front plate 10 (overall thickness: 30 μm) as that prepared in Example 1 is attached to the surface of the exposed adhesive layer. An optical laminate having the same structure as that of FIG. 2 was obtained except that the adhesive layer 61 was provided instead of the third adhesive layer 60.

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

<Example 4>
An optical laminate was obtained in the same manner as in Example 1 except that 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 as the front plate 10.

<Example 5>
An optical laminate was obtained in the same manner as in Example 2 except that 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 as the front plate 10.

<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 part Radical polymerization initiator (2,2'-azobisisobutyronitrile): 0.2 parts Solvent (ethyl acetate): 80 parts 0.3 parts of the cross-linking agent (“Coronate L” manufactured by Toso Co., Ltd.) and 0.5 parts of the silane coupling agent (“X-12-981” manufactured by Shinetsu Silicon Co., Ltd.) are mixed with the acrylic resin. Ethyl acetate was added so that the solid content concentration became 10% to obtain a pressure-sensitive adhesive composition.
The obtained pressure-sensitive adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (release film B, thickness 38 μm) using an applicator so that the thickness after drying was 25 μm. The coating layer was dried at 100 ° C. for 1 minute to obtain a film having an adhesive layer. Then, another polyethylene terephthalate film (release film A, thickness 38 μm) that had been released from the mold was attached onto the exposed surface of the pressure-sensitive adhesive layer. Then, it was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 50% RH.
In this way, the pressure-sensitive adhesive sheet B composed of the release film A / the pressure-sensitive adhesive layer / the release film B was produced.
The storage elastic modulus of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet B at 25 ° C. was 0.05 MPa.

(2) Preparation of Optical Laminate A polyimide film (tensile elastic modulus: 5.6 GPa) having a hard coat layer on both sides having an overall thickness of 70 μm was used as the front plate 10, and the first pressure-sensitive adhesive layer was used. An optical laminate was obtained in the same manner as in Example 2 except that the pressure-sensitive adhesive sheet B produced in (1) above 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 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 as the front plate 10.

<Example 8>
An optical laminate was obtained in the same manner as in Example 2 except that 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 as the front plate 10.

<Example 9>
FIG. 2 is the same as in Example 1 except that 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 as the laminate A. An optical laminate having the same structure as that of the above was obtained. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90.

The laminate A used in this example was produced 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 about 4.9 times by dry stretching. Further, the film was immersed in pure water at 60 ° C. for 1 minute while maintaining the tension state. Next, the film was immersed in an aqueous solution at 28 ° C. having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 for 60 seconds. Then, the film was immersed in an aqueous solution at 72 ° C. having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 for 300 seconds. 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 resin film (thickness 13 μm) were bonded to each other via an aqueous adhesive to obtain a laminate A as a polarizing plate.

<Example 10>
The third layer A was the same as in Example 5 except that a layered 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. An optical laminate having the same structure as that of FIG. 2 was obtained except that the adhesive layer 61 was provided instead of the adhesive layer 60. The cyclic polyolefin resin film corresponds to the thermoplastic resin film layer 90.
The procedure for producing the laminate A used in this example is the same as in Example 9.

<Comparative example 1>
The same 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 a polyimide film (tensile elastic modulus: 5.5 GPa) having hard coat layers on both sides having an overall thickness of 50 μm was used as the front plate 10.

<Comparative example 4>
An optical laminate was obtained in the same manner as in Comparative Example 1 except that 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 as the front plate 10.

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

(Evaluation test)
[A] Evaluation of reflected reflection image The optical laminate was placed in a dark room with the front plate side facing up, and a fluorescent lamp consisting of two linear fluorescent tubes on the ceiling of the room 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 laminate was subjected to a flexibility test according to the following procedure. FIG. 11 is a schematic view illustrating the method of the flexibility test.
A bending device (“STS-VRT-500” manufactured by Science Town) provided with two stages 501 and 502 was prepared, and the optical laminate 100 was placed on the stages 501 and 502 (FIG. 11 (a)). 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 about the gap C between the two stages, and the two stages 501 and 502 initially form the same plane. Rotate the two stages 501 and 502 upward by 90 degrees with the positions P1 and P2 as the center of the rotation axis to close the two stages 501 and 502 (FIG. 11B) and 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 and less than 100,000 times B (usable): 30,000 times or more and less than 50,000 times C (slightly inferior): 10,000 times or more and 30,000 times Less than D (inferior): less than 10,000 times

1,2 Optical laminate, 10 Front plate, 20 First adhesive layer, 30 Polarizer layer, 40 Second adhesive layer, 41 Release film B, 50 First retardation layer, 51 Base film, 60 Third Adhesive layer, 61 Adhesive layer, 70 Second retardation layer, 80 Support substrate, 90 Thermoplastic film layer, 100 Optical laminate, 501,502 stages.

Claims (4)

The front plate, the pressure-sensitive adhesive layer (A), the polarizer layer, and the n-layer [n is 1 or 2 . ], Which is an optical laminate containing the pressure-sensitive adhesive layer (B) and the supporting base material in this order.
The front plate has a tensile elastic modulus of 4.0 GPa or more at a temperature of 23 ° C. and a relative humidity of 55% RH.
The pressure-sensitive adhesive layer (A) and the pressure-sensitive adhesive layer (B) have a storage elastic modulus of 0.02 MPa or more and 2 MPa or less at 25 ° C.
The following formula (1):
0.2 ≤ T / C _total (1)
[In equation (1),
T represents the thickness [μm] of the front plate.
C _total represents the sum of the creep values C [%] at 25 ° C. of each pressure-sensitive adhesive layer arranged between the front plate and the supporting base material. ]
Satisfy ,
Further including one or more retardation layers arranged between the polarizer layer and the supporting base material.
The retardation layer is an optical laminate containing a cured product of a polymerizable liquid crystal compound . The following formula (2):
T / C _total ≤ 1.2 (2)
[In the formula (2), T and C _total have the same meanings as described above. ]
The optical laminate according to claim 1, further satisfying. The optical laminate according to claim 1 or 2 , wherein the polarizer layer contains a cured product of a polymerizable liquid crystal compound. A display device comprising the optical laminate according to any one of claims 1 to 3 .

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