WO2020230493A1

WO2020230493A1 - Optical laminate and display device

Info

Publication number: WO2020230493A1
Application number: PCT/JP2020/016026
Authority: WO
Inventors: 大山姜
Original assignee: 住友化学株式会社
Priority date: 2019-05-15
Filing date: 2020-04-09
Publication date: 2020-11-19
Also published as: JP7312013B2; JP2020187595A; KR20220006528A; TW202106504A; CN113811799A

Abstract

The purpose of the present invention is to provide an optical laminate that is provided sequentially with a front surface plate, a polarizing plate, and a touch sensor panel and that has excellent shock resistance. This optical laminate is sequentially provided with: a front surface plate; a polarizing plate; a first adhesive layer; and a touch sensor panel. The polarizing plate is provided with a protective layer on the outermost surface on the first adhesive layer side. The protective layer satisfies formula (1a): a×b≥700, where a [mJ/mm³] represents toughness, and b [µm] represents thickness.

Description

Optical laminate and display device

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

Japanese Unexamined Patent Publication No. 2017-054140 (Patent Document 1) describes a touch panel laminate used in an optical display device.

Japanese Unexamined Patent Publication No. 2017-054140

The present invention provides an optical laminate including a front plate, a polarizing plate, and a touch sensor panel in this order, which has excellent impact resistance, and a display device including the optical laminate. The purpose.

The present invention provides the following optical laminate and display device.

[1] An optical laminate including a front plate, a polarizing plate, a first adhesive layer, and a touch sensor panel in this order.
The polarizing plate is provided with a protective layer on the outermost surface on the side of the first pressure-sensitive adhesive layer.
An optical laminate satisfying the relationship of the following formula (1a), where the toughness is a [mJ / mm ³ ] and the thickness is b [μm] for the protective layer.
a × b ≧ 700 (1a)

[2] A second adhesive layer provided on the surface of the touch sensor panel opposite to the first adhesive layer side is further provided.
Assuming that the thickness of the first pressure-sensitive adhesive layer is t1 [μm] and the thickness of the second pressure-sensitive adhesive layer is t2 [μm], the relationship of the following formula (2a) and the following formula (3a) is satisfied, according to [1]. The optical laminate according to the description.
t1 / t2 ≧ 0.1 (2a)
t1 / t2 ≦ 2 (3a)
[3] The optical laminate according to [1] or [2], wherein the protective layer is provided with a retardation layer on a surface opposite to the first pressure-sensitive adhesive layer side.
[4] The optical laminate according to [3], wherein the retardation layer contains a cured product of a polymerizable liquid crystal compound.
[5] The optical laminate according to any one of [1] to [4], wherein the retardation layer is a positive C layer or a quarter wavelength layer.
[6] The optical laminate according to any one of [1] to [5], wherein the touch sensor panel includes a base material layer and a transparent conductive layer provided on the base material layer.
[7] A display device including the optical laminate according to any one of [1] to [6].

According to the present invention, it is possible to provide an optical laminate having excellent impact resistance and a display device including the optical laminate.

It is the schematic sectional drawing which shows an example of the optical laminated body of this invention. It is schematic cross-sectional view which shows typically an example of the retardation body including the retardation layer which is a liquid crystal layer. It is a schematic sectional drawing schematically showing another example of the retardation body including the retardation layer which is a liquid crystal layer.

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.

<Optical laminate>
FIG. 1 is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. The optical laminate 100 shown in FIG. 1 includes a front plate 10, a bonding layer 43, a polarizing plate 20, a first pressure-sensitive adhesive layer 41, a touch sensor panel 30, and a second pressure-sensitive adhesive layer 42 in this order. The optical laminate 100 of the present invention may have a structure that does not have the second pressure-sensitive adhesive layer 42, or may have a structure that does not have the bonding layer 43.

The polarizing plate 20 is provided with a protective layer 201 on the outermost surface on the side of the first pressure-sensitive adhesive layer 41, and further includes a polarizing layer 200 including a polarizing element. The touch sensor panel 30 includes a base material layer 32 and a transparent conductive layer 31 provided on the surface of the base material layer 32 on the side of the first pressure-sensitive adhesive layer 41. The touch sensor panel 30 may have a configuration that does not have the base material layer 32.

Although the protective layer 201 of the polarizing plate 20 and the base material layer 32 of the touch sensor panel 30 are usually a single layer, they are composed of a plurality of layers including a surface treatment layer and a plurality of layers laminated without interposing a pressure-sensitive adhesive layer. As for the plurality of layers, it is assumed that the protective layer 201 or the base material layer 32 is formed by the entire multilayer.

Assuming that the protective layer 201 of the polarizing plate 20 has a toughness of a [mJ / mm ³ ] and a thickness of b [μm], the relationship of the following formula (1a) is satisfied. In the present specification, toughness a [mJ / mm ³ ] is a value measured at room temperature (temperature 23 ° C.) by the method described in Examples described later.
a × b ≧ 700 (1a)

In the optical laminate, the impact resistance can be improved by satisfying the relationship of the formula (1a) in the protective layer 201. From the viewpoint of further improving the impact resistance of the optical laminate, the protective layer 201 preferably satisfies the relationship of the formula (1b), and more preferably the relationship of the formula (1c). The protective layer 201 may satisfy the relationship of the formula (1d).
a × b ≧ 1000 (1b)
a × b ≧ 2000 (1c)
a × b ≦ 5000 (1d)

Assuming that the thickness of the first pressure-sensitive adhesive layer 41 is t1 [μm] and the thickness of the second pressure-sensitive adhesive layer 42 is t2 [μm] from the viewpoint of improving the bending resistance in the optical laminate, the following formula (2a) and It is preferable to satisfy the relationship of the following formula (3a).
t1 / t2 ≧ 0.1 (2a)
t1 / t2 ≦ 2 (3a)

From the viewpoint of further improving the bending resistance of the optical laminate, it is more preferable to satisfy the relationship of the following formula (3b), further preferably the relationship of the following formula (3c), and the relationship of the following formula (3d). It is more preferable to satisfy. The optical laminate may satisfy the relationship of the following formula (3e) or the following formula (3f).
t1 / t2 ≦ 1.5 (3b)
t1 / t2 ≦ 1 (3c)
t1 / t2 ≤ 0.8 (3d)
t1 / t2 ≤ 0.5 (3e)
t1 / t2 ≧ 0.2 (3f)

It is preferable that the optical laminate 100 can be bent at least in the direction in which the front plate 10 is outward. The term "flexible" means that the front plate 10 can be bent in the outward direction without causing cracks. The optical laminate according to the present invention is excellent in impact resistance, and can be considered to be excellent in both impact resistance and bending resistance.

The shape of the optical laminate 100 in the plane direction 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 shape of the optical laminate 100 in the plane direction 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. Each layer constituting the optical laminate 100 may have corners R-processed, end portions notched, or perforated.

The thickness of the optical laminate 100 is not particularly limited because it varies depending on the functions required of the optical laminate, the application of the laminate, and the like, but is, for example, 20 μm or more and 1,000 μm or less, preferably 50 μm or more and 500 μm or less.

The optical laminate 100 can be used, for example, in a display device or the like. The display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, and an electroluminescent display device. The optical laminate 100 is suitable for a flexible display device. The display device including the optical laminate of the present invention has excellent impact resistance.

The optical laminate 100 includes a front plate 10, a polarizing plate 20, and a touch sensor panel 30. The optical laminate 100 preferably has a configuration that can be a part of the display device by being used in the display device, and the elements that the display device can have may be provided without limitation, for example, partial. A colored layer, a protective film, a retardation film, etc. formed on the surface may be provided. These elements may be included in the polarizing layer 200 of the polarizing plate 20.

[Front plate]
The material and thickness of the front plate 10 are not limited as long as it is a plate-like body capable of transmitting light, and the front plate 10 may be composed of only one layer or may be composed of two or more layers. Examples thereof include a resin plate-like body (for example, a resin plate, a resin sheet, a resin film, etc.), a glass plate-like body (for example, a glass plate, a glass film, etc.) and the like. The front plate can be a layer constituting the outermost surface of the display device. The front plate may be a laminate of a resin plate-like body and a glass plate-like body.

The thickness of the front plate 10 may be, for example, 30 μm or more and 500 μm or less, preferably 40 μm or more and 200 μm or less, and more preferably 50 μm or more and 100 μm or less.
In the present invention, the thickness of each layer can be measured according to the thickness measuring method described in Examples described later.

When the front plate 10 is a resin plate-like body, the resin plate-like body is not limited as long as it can transmit light. Examples of the resin constituting the resin plate such as a resin film include triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, and polystyrene. Polyamide, polyetherimide, poly (meth) acrylic, polyimide, polyether sulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone , Polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyamideimide and the like. These polymers can be used alone or in combination of two or more. From the viewpoint of improving strength and transparency, a resin film formed of a polymer such as polyimide, polyamide, or polyamideimide is preferable.

The front plate 10 may be a film provided with a hard coat layer on at least one surface of the base film. As the base film, a film made of the above resin 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, a resin film having improved hardness and scratch resistance can be obtained. The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include acrylic resin, silicone resin, polyester resin, urethane resin, amide resin, epoxy resin and the like. The hard coat layer may contain additives in order to improve the hardness. Additives are not limited and include inorganic fine particles, organic fine particles, or mixtures thereof.

When the front plate 10 is a glass plate, tempered glass for a display is preferably used as the glass plate. The thickness of the glass plate can be, for example, 10 μm or more and 1000 μm or less, 20 μm or more and 500 μm or less, or 50 μm or more and 500 μm or less.
By using the glass plate, the front plate 10 having excellent mechanical strength and surface hardness can be constructed.

When the optical laminate 100 is used in a display device, 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 touch detected by the touch sensor panel 30. It may also have a function as an operation surface for performing the above, and may further have a blue light cut function, a viewing angle adjusting function, and the like.

[Touch sensor panel]
The touch sensor panel 30 is a sensor capable of detecting the position touched by the front plate 10, and the detection method is not limited as long as it has the transparent conductive layer 31, and the resistance film method and the capacitance are not limited. Examples of touch sensor panels include a capacitance method, an optical sensor method, an ultrasonic method, an electromagnetic induction coupling method, and a surface acoustic wave method. Among them, the capacitance type touch sensor panel is preferably used in terms of low cost, fast reaction speed, and thin film formation. The touch sensor panel 30 includes a base material layer 32 and a transparent conductive layer 31 provided on the surface of the base material layer 32 on the first adhesive layer 41 side from the viewpoint of improving impact resistance. It is preferably configured.
In the configuration in which the transparent conductive layer 31 is provided on the surface of the base material layer 32, the base material layer 32 and the transparent conductive layer 31 may be in contact with each other (for example, the first described later). The touch sensor panel manufactured by the method), the base material layer 32 and the transparent conductive layer 31 may not be in contact with each other (for example, the touch sensor panel manufactured by the second method described later). The touch sensor panel 30 may include an adhesive layer, a separation layer, a protective layer, and the like in addition to the base material layer 32 and the transparent conductive layer 31. Examples of the adhesive layer include an adhesive layer and an adhesive layer.

An example of a capacitance type touch sensor panel is composed of a base material layer, a transparent conductive layer for position detection provided on the surface of the base material layer, and a touch position detection circuit. In a display device provided with an optical laminate having a capacitance type touch sensor panel, when the surface of the front plate 10 is touched, the transparent conductive layer is grounded via the capacitance of the human body at the touched point. Will be done.
The touch position detection circuit detects the grounding of the transparent conductive layer, and the touched position is detected. By having a plurality of transparent conductive layers separated from each other, more detailed position detection becomes possible.

The transparent conductive layer may be a transparent conductive layer made of a metal oxide such as ITO, or may be a metal layer made of a metal such as aluminum, copper, silver, gold, or an alloy thereof.

The separation layer can be a layer formed on a substrate such as glass and for separating the transparent conductive layer formed on the separation layer from the substrate together with the separation layer. The separation layer is preferably an inorganic layer or an organic layer. Examples of the material forming the inorganic layer include silicon oxide. As the material for forming the organic material layer, for example, a (meth) acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like can be used.

The touch sensor panel 30 may be provided with a protective layer that is in contact with the transparent conductive layer 31 and protects the conductive layer. The protective layer contains at least one of an organic insulating film and an inorganic insulating film, and these films can be formed by a spin coating method, a sputtering method, a vapor deposition method or the like.

The touch sensor panel 30 can be manufactured, for example, as follows. In the first method, the base material layer 32 is first laminated on the glass substrate via the adhesive layer. A transparent conductive layer 31 patterned by photolithography is formed on the base material layer 32. By applying heat, the glass substrate and the base material layer 32 are separated to obtain a touch sensor panel 30 composed of the transparent conductive layer 31 and the base material layer 32.

In the second method, a separation layer is first formed on the glass substrate, and if necessary, a protective layer is formed on the separation layer. A transparent conductive layer 31 patterned by photolithography is formed on the separation layer (or protective layer). A peelable protective film is laminated on the transparent conductive layer 31, and the transparent conductive layer 31 to the separation layer are transferred to separate the glass substrate. A touch having the transparent conductive layer 31, the separation layer, the adhesive layer, and the base material layer 32 in this order by adhering the base material layer 32 and the separation layer via the adhesive layer and peeling off the peelable protective film. The sensor panel 30 is obtained.
The laminated body composed of the transparent conductive layer 31 and the separation layer may be used as the touch sensor panel 30 without being bonded to the base material layer 32.

The base material layer 32 of the touch sensor panel includes triacetyl cellulose, polyethylene terephthalate, cycloolefin polymer, polyethylene naphthalate, polyolefin, polycycloolefin, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, polynorbornene and the like. Resin film can be mentioned. Polyethylene terephthalate is preferably used from the viewpoint of easily forming a base material layer having a desired toughness.

The base material layer 32 of the touch sensor panel preferably has a thickness of 50 μm or less, and more preferably 30 μm or less, from the viewpoint of easily forming an optical laminate having excellent bending resistance. The base material layer 32 of the touch sensor panel has a thickness of, for example, 5 μm or more.

[Polarizer]
Examples of the polarizing plate 20 include a stretched film on which a dichroic dye is adsorbed, a film containing a liquid crystal layer coated with a composition containing the dichroic dye and a polymerizable compound and cured as a polarizer, and the like. The polarizing plate 20 includes a protective layer 201 in addition to a polarizing element, and further includes a retardation layer and the like.

(Polarizer)
As the dichroic dye, specifically, iodine or a dichroic organic dye is used. For dichroic organic dyes, C.I. I. Included are dichroic direct dyes consisting of disuazo compounds such as DIRECT RED 39 and dichroic direct dyes consisting of compounds such as trisazo and tetrakisazo. The polarizer obtained by applying and curing the composition containing the dichroic dye and the polymerizable compound is, for example, a composition containing a dichroic dye having a liquid crystal property or a composition containing a dichroic dye and a polymerizable liquid crystal. Is applied and cured to form a liquid crystal layer. A liquid crystal layer to which a composition containing a dichroic dye and a polymerizable compound is applied and cured is preferable because there is no limitation in the bending direction as compared with a stretched film on which a dichroic dye is adsorbed.

(1) Polarizing Plate with Polarizer as Stretched Film A polarizing plate having a stretched film having a dichroic dye adsorbed as a polarizing plate will be described. A stretched film on which a dichroic dye, which is a polarizer, is adsorbed is usually bicolorized by a step of uniaxially stretching the polyvinyl alcohol-based resin film and dyeing the polyvinyl alcohol-based resin film with the bicolor dye. It is produced through a step of adsorbing a dye, a step of treating a polyvinyl alcohol-based resin film on which a bicolor dye is adsorbed with an aqueous boric acid solution, and a step of washing with water after the treatment with the aqueous boric acid solution. Such a polarizing element may be used as it is as a polarizing plate, or a polarizing plate having a transparent protective film bonded to one side or both sides thereof may be used as a polarizing plate. The thickness of the polarizer thus obtained is preferably 2 μm or more and 40 μm or less.

The polyvinyl alcohol-based resin is obtained by saponifying the 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 acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 mol% or more and 100 mol% or less, 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 about 1,000 or more and 10,000 or less, and preferably 1,500 or more and 5,000 or less.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizer. The method for forming the film of the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw film can be, for example, about 10 μm or more and 150 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing with a dichroic dye, at the same time as dyeing, or after dyeing. When the uniaxial stretching is performed after staining, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to perform uniaxial stretching at these multiple stages. In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch the rolls. Further, the uniaxial stretching may be a dry stretching in which stretching is performed in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is swollen using a solvent. The draw ratio is usually about 3 to 8 times.

The thickness of the polarizing plate provided with the stretched film as a polarizer may be, for example, 1 μm or more and 400 μm or less, and may be 5 μm or more and 100 μm or less.

The material of the protective film to be bonded to one side or both sides of the polarizer is not particularly limited, but is, for example, a cellulose acetate-based film made of a resin such as a cyclic polyolefin-based resin film, triacetyl cellulose, or diacetyl cellulose. Films known in the art such as resin films, polyester resin films made of resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, polycarbonate resin films, (meth) acrylic resin films, and polypropylene resin films. Can be mentioned. From the viewpoint of thinning, the thickness of the protective film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and usually 5 μm or more, preferably 20 μm or more. .. The protective film may or may not have a phase difference.

(2) Polarizing Plate with Polarizer as Liquid Crystal Layer A polarizing plate having a liquid crystal layer as a polarizing element will be described. The liquid crystal layer formed by applying a composition containing a dichroic dye and a polymerizable compound used as a polarizer includes a composition containing a dichroic dye having liquid crystal properties, or a dichroic dye and a liquid crystal. Examples thereof include a liquid crystal layer obtained by applying a composition containing a compound to a substrate and curing the composition. The liquid crystal layer may be used as a polarizing plate by peeling off the base material or together with the base material, or may be used as a polarizing plate in a configuration having a protective film on one side or both sides thereof. Examples of the protective film include those having the same polarizing plate as the polarizing plate which is a stretched film.

The liquid crystal layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound is preferably thin, but if it is too thin, the strength is lowered and the processability tends to be inferior. The thickness of the liquid crystal layer is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 μm or more and 3 μm or less.

The thickness of the polarizing plate having the liquid crystal layer as a polarizer may be, for example, 1 μm or more and 50 μm or less.

(Phase difference layer)
The polarizing plate can include one layer or two or more retardation layers. The retardation layer is a layer that gives a predetermined phase difference to light, and examples thereof include optical compensation layers such as a 1/2 wavelength layer, a 1/4 wavelength layer, and a positive C layer. The retardation layer may be a retardation layer having a positive wavelength dispersion or a retardation layer having a reverse wavelength dispersion. The retardation layer may be an element in the retardation body that is configured together with other layers. Examples of the layer other than the retardation layer in the retardation body include a base material layer, an alignment layer, a protective layer, and the like. The other layers can be those that do not affect the value of the phase difference.

Examples of the retardation layer include a liquid crystal layer containing a cured product of a polymerizable liquid crystal compound, or a stretched film. The retardation layer, which is a liquid crystal layer, is generally easier to thin than the retardation layer, which is a stretched film.

When the retardation layer is a liquid crystal layer, the thickness is preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5 μm.

As the configuration of the polarizing plate 20, the following configuration including two retardation layers together with a polarizing element is exemplified. From the side closest to the front plate 10
i) A combination of a polarizer, a 1/2 wavelength layer, and a 1/4 wavelength layer,
ii) Polarizer, 1/4 wavelength layer, positive C layer combination,
And so on. The configurations of i) and ii) above can provide a circular polarizing plate. The optical laminate can be prevented from reflecting external light by providing the polarizing plate 20 with a circular polarizing plate.

The 1/2 wavelength layer gives a phase difference of π (= λ / 2) to the electric field vibration direction (polarization plane) of the incident light, and has a function of changing the direction of linear polarization (polarization direction). .. Further, when the circularly polarized light is incident, the rotation direction of the circularly polarized light can be reversed.

The 1/2 wavelength layer is a layer in which Re (λ), which is an in-plane retardation value at a specific wavelength λ nm, satisfies Re (λ) = λ / 2. Re (λ) = λ / 2 may be achieved at any wavelength in the visible light region, but it is particularly preferable that it is achieved at a wavelength of 550 nm. The in-plane retardation value of Re (550) at a wavelength of 550 nm preferably satisfies 210 nm ≦ Re (550) ≦ 300 nm. Further, it is more preferable to satisfy 220 nm ≦ Re (550) ≦ 290 nm.

The 1/4 wavelength layer gives a phase difference of π / 2 (= λ / 4) to the electric field vibration direction (polarization plane) of the incident light, and linearly polarized light of a specific wavelength is circularly polarized (or circularly polarized). It has the function of converting polarized light (to linearly polarized light).

The 1/4 wavelength layer is a layer in which Re (λ), which is an in-plane retardation value at a specific wavelength λ nm, satisfies Re (λ) = λ / 4, and is achieved at any wavelength in the visible light region. However, it is preferable that the wavelength is 550 nm. It is preferable that Re (550), which is an in-plane retardation value at a wavelength of 550 nm, satisfies 100 nm ≦ Re (550) ≦ 160 nm. Further, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

The inverse wavelength dispersibility is an optical characteristic in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength, and the following equation (4):
Re (450) ≤ Re (550) ≤ Re (650) (4)
To meet.

Examples of the optical compensation layer include a positive A layer and a positive C layer. The positive A layer has Nx> Ny when the refractive index in the slow axis direction in the plane is Nx, the refractive index in the phase advance axis direction in the plane is Ny, and the refractive index in the thickness direction is Nz. Satisfy the relationship. The positive A layer preferably satisfies the relationship of Nx> Ny ≧ Nz. The positive A layer can also function as a quarter wavelength layer. The positive C layer satisfies the relationship of Nz> Nx ≧ Ny.

The optical characteristics of the retardation layer can be adjusted by the orientation state of the liquid crystal compound constituting the retardation layer or the stretching method of the stretched film constituting the retardation layer. By appropriately adjusting the optical characteristics of the retardation layer in the polarizing plate 20, the polarizing plate 20 having antireflection performance can be obtained.

(1) Phase difference layer which is a liquid crystal layer A case where the retardation layer is a liquid crystal layer will be described. FIG. 2 is a schematic cross-sectional view schematically showing an example of a retardation body including a retardation layer which is a liquid crystal layer and another layer. As shown in FIG. 2, the retardation body 50 is formed by laminating a base material layer 51, an alignment layer 52, and a retardation layer 53 which is a liquid crystal layer in this order. The retardation body 50 is not limited to the configuration shown in FIG. 2 as long as it includes the retardation layer 53 which is a liquid crystal layer, and only the alignment layer 52 and the retardation layer 53 are separated from the base material layer 51. It may be composed of only the retardation layer 53 which is a liquid crystal layer by peeling off the base material layer 51 and the alignment layer 52.

FIG. 3 is a schematic cross-sectional view schematically showing another example of a retardation body including a retardation layer which is a liquid crystal layer and another layer. The retardation body 55 shown in FIG. 3 is formed by laminating a base material layer 56, an adhesive layer 57, and a retardation layer 53 in this order. In the retardation body 55, the retardation layer 53 of the retardation body 50 shown in FIG. 2 and another base material layer 56 are bonded to each other via an adhesive layer 57, and then the base material layer 51 or the base material layer 51 is bonded. And the alignment layer 52 is peeled off and formed. Examples of the adhesive layer 57 include an adhesive layer and an adhesive layer.

The base material layer 51 has a function as a support layer for supporting the alignment layer 52 formed on the base material layer 51 and the retardation layer 53 which is a liquid crystal layer. The base material layer 51 is preferably a film made of a resin material.

As the resin material of the base material layer 51, for example, a resin material having excellent transparency, mechanical strength, thermal stability, stretchability, etc. is used. Specifically, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth) acrylic acid, poly (meth) methyl acrylate and the like. (Meta) acrylic acid resin; cellulose ester resin such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; vinyl alcohol resin such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resin; polystyrene resin; poly Arilate-based resin; polysulfone-based resin; polyethersulfone-based resin; polyamide-based resin; polyimide-based resin; polyetherketone-based resin; polyphenylene sulfide-based resin; polyphenylene oxide-based resin, and mixtures and copolymers thereof. Can be done. Among these resins, it is preferable to use any one of cyclic polyolefin-based resin, polyester-based resin, cellulose ester-based resin and (meth) acrylic acid-based resin, or a mixture thereof. The above-mentioned "(meth) acrylic acid" means "at least one of acrylic acid and methacrylic acid".

The base material layer 51 may be a single layer obtained by mixing one or more of the above resins, or may have a multi-layer structure of two or more layers.

Any additive may be added to the resin material forming the resin film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a colorant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a colorant.

The thickness of the base material layer 51 is not particularly limited, but is generally preferably 5 to 200 μm, more preferably 10 to 200 μm, and 10 to 150 μm from the viewpoint of workability such as strength and handleability. It is more preferable to have.

In order to improve the adhesion between the base layer 51 and the alignment layer 52, at least the surface of the base layer 51 on the side where the alignment layer 52 is formed may be subjected to corona treatment, plasma treatment, flame treatment, or the like. A primer layer or the like may be formed. When the base material layer 51, or the base material layer 51 and the alignment layer 52 are peeled off to form a retardation layer, the peeling can be facilitated by adjusting the adhesion at the peeling interface. The description of the base material layer 51 is applied to the material, thickness, treatment, etc. of the base material layer 56.

The alignment layer 52 has an orientation regulating force that orients the liquid crystal compound contained in the retardation layer 53 of the liquid crystal layer formed on the alignment layer 52 in a desired direction. Examples of the oriented layer 52 include an oriented polymer layer formed of an oriented polymer, a photo-aligned polymer layer formed of a photo-aligned polymer, and a grub-aligned layer having an uneven pattern or a plurality of grubs (grooves) on the layer surface. Can be done. The thickness of the alignment layer 52 is usually 0.01 to 10 μm, preferably 0.01 to 5 μm.

The oriented polymer layer can be formed by applying a composition in which the oriented polymer is dissolved in a solvent to the base material layer 51 to remove the solvent, and if necessary, rubbing treatment. In this case, the orientation regulating force can be arbitrarily adjusted in the orientation polymer layer formed of the orientation polymer depending on the surface condition of the orientation polymer and the rubbing conditions.

The photoaligned polymer layer can be formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent to the base material layer 51 and irradiating it with polarized light. In this case, in the photo-alignment polymer layer, the orientation-regulating force can be arbitrarily adjusted depending on the polarization irradiation conditions of the photo-alignment polymer.

The grub alignment layer is active on a plate-shaped master having grooves on the surface, for example, a method of forming an uneven pattern by exposure, development, etc. through an exposure mask having a pattern-shaped slit on the surface of a photosensitive polyimide film. A method of forming an uncured layer of an energy ray-curable resin and transferring this layer to a base material layer 51 for curing, forming an uncured layer of an active energy ray-curable resin on the base material layer 51, and this It can be formed by a method of forming irregularities and curing by pressing a roll-shaped master having irregularities against the layer.

The retardation layer 53, which is a liquid crystal layer, is not particularly limited as long as it gives a predetermined phase difference to light, and for example, an optical compensation layer such as a 1/2 wavelength layer, a 1/4 wavelength layer, and a positive C layer can be used. Can be mentioned.

The retardation layer 53, which is a liquid crystal layer, can be formed by using a known liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and a rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and a mixture thereof can be used. Further, the liquid crystal compound may be a polymer liquid crystal compound, a polymerizable liquid crystal compound, or a mixture thereof. Examples of the liquid crystal compound include JP-A-11-513019, JP-A-2005-289980, JP-A-2007-108732, JP-A-2010-2404038, JP-A-2010-31223, and JP-A. Liquid crystal compounds described in JP-A-2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, WO2017 / 043438 and JP-A-2011-207765. Can be mentioned.

For example, when a polymerizable liquid crystal compound is used, a composition containing the polymerizable liquid crystal compound is applied onto the alignment layer 52 to form a coating film, and the coating film is cured to form a retardation layer 53. Can be formed. The retardation layer 53 formed in this way contains a cured product of the polymerizable liquid crystal compound. The thickness of the retardation layer 53 is preferably 0.5 μm to 10 μm, and more preferably 0.5 to 5 μm.

The composition containing the polymerizable liquid crystal compound may contain a polymerization initiator, a polymerizable monomer, a surfactant, a solvent, an adhesion improver, a plasticizer, an orienting agent and the like in addition to the liquid crystal compound. Examples of the method for applying the composition containing the polymerizable liquid crystal compound include known methods such as a die coating method. Examples of the curing method of the composition containing the polymerizable liquid crystal compound include known methods such as irradiation with active energy rays (for example, ultraviolet rays).

(2) Phase Difference Layer as Stretched Film A case where the retardation layer is a stretched film will be described. The stretched film is usually obtained by stretching the base material. As a method of stretching the base material, for example, a roll (winding body) in which the base material is wound on a roll is prepared, and the base material is continuously unwound and unwound from the winding body. The base material is transferred to the heating furnace. The set temperature of the heating furnace is in the range of the base material near the glass transition temperature (° C) to [glass transition temperature +100] (° C), preferably near the glass transition temperature (° C) to [glass transition temperature +50] (° C). The range of. In the heating furnace, when the base material is stretched in the traveling direction or in the direction orthogonal to the traveling direction, the transport direction and tension are adjusted to incline at an arbitrary angle to perform uniaxial or biaxial thermal stretching treatment. Do. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

Further, the method of stretching in the oblique direction is not particularly limited as long as the orientation axis can be continuously tilted to a desired angle, and a known stretching method can be adopted. Examples of such a stretching method include the methods described in JP-A-50-83482 and JP-A-2-113920. When imparting retardation to a film by stretching, the thickness after stretching is determined by the thickness before stretching and the stretching ratio.

The base material is usually a transparent base material. The transparent base material means a base material having transparency capable of transmitting light, particularly visible light, and the transparency means a characteristic that the transmittance for light having a wavelength of 380 to 780 nm is 80% or more. Say. Specific examples of the transparent base material include a translucent resin base material. Resins constituting the translucent resin base material include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; triacetylcellulose, Cellulose esters such as diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of availability and transparency, polyethylene terephthalate, polymethacrylic acid ester, cellulose ester, cyclic olefin resin or polycarbonate are preferable.

Cellulose ester is an esterified part or all of the hydroxyl groups contained in cellulose and can be easily obtained from the market. Cellulose ester substrates are also readily available on the market. Examples of commercially available cellulose ester base materials include "Fujitac (registered trademark) film" (FUJIFILM Corporation); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Opto Co., Ltd.). ..

Polymethacrylic acid ester and polyacrylic acid ester (hereinafter, polymethacrylic acid ester and polyacrylic acid ester may be collectively referred to as (meth) acrylic resin.
) Is readily available from the market.

Examples of the (meth) acrylic resin include homopolymers of methacrylic acid alkyl esters or acrylic acid alkyl esters, and copolymers of methacrylic acid alkyl esters and acrylic acid alkyl esters. Specific examples of the methacrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate and propyl methacrylate, and specific examples of the acrylic acid alkyl ester include methyl acrylate, ethyl acrylate and propyl acrylate. As the (meth) acrylic resin, those commercially available as general-purpose (meth) acrylic resins can be used. As the (meth) acrylic resin, what is called an impact resistant (meth) acrylic resin may be used.

It is also preferable to include rubber particles in the (meth) acrylic resin in order to further improve the mechanical strength. The rubber particles are preferably acrylic particles. Here, the acrylic rubber particles have rubber elasticity obtained by polymerizing an acrylic monomer containing an acrylic acid alkyl ester as a main component, such as butyl acrylate or 2-ethylhexyl acrylate, in the presence of a polyfunctional monomer. It is a particle. The acrylic rubber particles may be formed by forming such particles having rubber elasticity in a single layer, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multi-layer structure, those having the above-mentioned particles having rubber elasticity as nuclei and covering them with a hard methacrylic acid alkyl ester polymer, and hard methacrylic acid alkyl ester polymers are used. A core made of an acrylic polymer having rubber elasticity as described above, or a hard core covered with an acrylic polymer having rubber elasticity, and a hard alkyl methacrylic acid ester around the core. Examples thereof include those covered with a system polymer. The rubber particles formed by the elastic layer usually have an average diameter in the range of about 50 to 400 nm.

The content of rubber particles in the (meth) acrylic resin is usually about 5 to 50 parts by mass per 100 parts by mass of the (meth) acrylic resin. Since the (meth) acrylic resin and the acrylic rubber particles are commercially available in a mixed state, the commercially available products can be used. Examples of commercially available (meth) acrylic resins containing acrylic rubber particles include "HT55X" and "Technoloy S001" sold by Sumitomo Chemical Co., Ltd. "Technoloy S001" is sold in the form of a film.

Cyclic olefin resin is easily available on the market. Commercially available cyclic olefin resins include "Topas" (registered trademark) [Ticona (Germany)], "Arton" (registered trademark) [JSR Co., Ltd.], "ZEONOR" (registered trademark) [Japan. Zeon Co., Ltd.], "ZEONEX" (registered trademark) [Zeon Corporation] and "Apel" (registered trademark) [Mitsui Chemicals Co., Ltd.]. Such a cyclic olefin resin can be used as a base material by forming a film by a known means such as a solvent casting method or a melt extrusion method. Further, a commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin base materials include "Sushina" (registered trademark) [Sekisui Chemical Co., Ltd.], "SCA40" (registered trademark) [Sekisui Chemical Co., Ltd.], and "Zeonor Film" (registered trademark). ) [Optes Co., Ltd.] and "Arton Film" (registered trademark) [JSR Co., Ltd.].

When the cyclic olefin resin is a copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, the content ratio of the structural unit derived from the cyclic olefin is the total structural unit of the copolymer. On the other hand, it is usually in the range of 50 mol% or less, preferably 15 to 50 mol%. Examples of the chain olefin include ethylene and propylene, and examples of the aromatic compound having a vinyl group include styrene, α-methylstyrene and alkyl-substituted styrene. When the cyclic olefin resin is a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the chain olefin is the content of the copolymer. The content ratio of the structural unit derived from the aromatic compound having a vinyl group is usually 5 to 80 mol% with respect to the total structural unit of the copolymer. Is. Such a ternary copolymer has an advantage that the amount of expensive cyclic olefins used can be relatively small in the production thereof.

(Protective layer)
The protective layer 201 included in the polarizing plate 200 is not particularly limited as long as it satisfies the relational expression of the formula (1a). As an example of the configuration of the polarizing plate 200, the retardation body 50 shown in FIG. 2 or the retardation body 55 shown in FIG. 3 is included, and the base material layer 51 of the retardation body 50 or the base material layer 56 of the retardation body 55 is protected. Examples include the configuration of layer 201. In this case, the above description of the base material layers 51 and 56 applies as it is to the description of the protective layer 201. For example, when the polarizing plate 200 is a circular polarizing plate having the configuration of i), the protective layer 201 can be the base material layers 51 and 56 that support the 1/4 wavelength layer, and the first adhesive of the protective layer 201 can be formed. A configuration in which a 1/4 wavelength layer is provided on the surface opposite to the agent layer 41 side can be mentioned. Further, when the polarizing plate 200 is a circular polarizing plate having the above ii) configuration, the protective layer 201 can be the base material layers 51 and 56 that support the positive C layer, and the first pressure-sensitive adhesive layer of the protective layer 201 can be used. A configuration in which a positive C layer is provided on the surface on the side opposite to the 41 side can be mentioned. In the above configuration, a retardation layer is provided on the surface of the protection layer 201, and the protection layer 201 and the retardation layer may be in contact with each other (for example, shown in FIG. 2). The retardation body 50), the protective layer 201 and the retardation layer may not be in contact with each other (for example, the retardation body 55 shown in FIG. 3).

Another example of the configuration of the polarizing plate 200 is a configuration in which the protective film 201 is the protective film bonded to the surface of the polarizing element on the first pressure-sensitive adhesive layer 41 side. In this case, the above description of the protective film is directly applied as the description of the protective layer 201. Further, as another example of the configuration of the polarizing plate 200, there is a configuration in which the protective layer 201 is bonded to the surface of the polarizing plate 200 on the side of the first pressure-sensitive adhesive layer 41 to form a constituent element of the polarizing plate 200. In this case, as the protective layer 201, the above-mentioned base material layer 51 or the same one as described in the above-mentioned protective film can be used.

[Adhesive layer]
The first pressure-sensitive adhesive layer 41 is a layer interposed between the polarizing plate 20 and the touch sensor panel 30. The second adhesive layer 42 is a layer provided on the surface of the touch sensor panel 30 opposite to the polarizing plate 20 side, and is used to bond the optical laminate 100 to another member such as a display panel. Can be used for. A release film may be attached to the surface of the second pressure-sensitive adhesive layer 42.

The first pressure-sensitive adhesive layer 41 and the second pressure-sensitive adhesive layer 42 are mainly composed of resins such as (meth) acrylic resin, rubber resin, urethane resin, ester resin, silicone resin, and polyvinyl ether resin. It can be composed of a pressure-sensitive adhesive composition. 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, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer containing one or more (meth) acrylic acid esters such as ethylhexyl as a monomer 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 meta) 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. 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 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.

It can be formed by applying an organic solvent diluent of the above pressure-sensitive adhesive composition on a base material 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 first pressure-sensitive adhesive layer 41 and the second pressure-sensitive adhesive layer 42 may be made of the same material or different materials. The thickness t1 of the first pressure-sensitive adhesive layer 41 and the thickness t2 of the second pressure-sensitive adhesive layer are not particularly limited, and are, for example, 3 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less, and 20 μm or more. There may be. The thickness t1 of the first pressure-sensitive adhesive layer 41 and the thickness t2 of the second pressure-sensitive adhesive layer are preferably selected so as to satisfy the above formulas (2a) and (3a).

The storage elastic modulus of the first pressure-sensitive adhesive layer 41 and the second pressure-sensitive adhesive layer 42 at a temperature of 25 ° C. is preferably 0.005 MPa or more and 1.0 MPa or less, and is 0.01 MPa or more and 0.5 MPa or less, respectively. Is more preferable, and 0.01 MPa or more and 0.2 MPa or less is further preferable. The storage modulus is measured by the method described in Examples below.

[Lated layer]
The bonding layer 43 is a layer interposed between the polarizing plate 20 and the front plate 10. The bonding layer 43 is not particularly limited, and can be formed from, for example, an adhesive layer, an aqueous adhesive layer, an active energy ray-curable adhesive layer, or the like. When the bonding layer 43 is formed from a pressure-sensitive adhesive, the pressure-sensitive adhesive composition described above can be used. The thickness of the bonded layer 43 is preferably 0.1 μm to 50 μm, more preferably 0.1 μm to 10 μm, and even more preferably 0.5 μm to 5 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

The front plates A1, protective layers B1 to B4, polarizing plates C1 to C4, touch sensor panels D1 and D2, and adhesive sheets E1 to E5 shown below were prepared.

[Front plate]
(Front plate A1)
A composition for a hard coat layer is coated on the surface of a transparent base film (polyamideimide film, thickness 50 μm), and then the solvent is dried and UV-cured to obtain a hard coat layer having a thickness of 10 μm on both surfaces of the base film. A front plate A1 (thickness 70 μm, tensile elastic modulus 6 GPa, length 177 mm × width 105 mm) was produced.

The composition for the hard coat layer is 30 parts by weight of multifunctional acrylate (MIWON Specialty Chemical, MIRAMER M340), 50 parts by weight of nanosilica sol (average particle size 12 nm, solid content 40%) dispersed in propylene glycol monomethyl ether, ethyl acetate. 17 parts by weight of photopolymerization initiator (Ciba, I184), 2.7 parts by weight, and 0.3 parts by weight of fluorine-based additive (Shinetsu Chemical Industry Co., Ltd., KY1203) are blended using a stirrer to mix polypropylene (PP). ) A composition for a hard coat layer was produced by filtering using a filter made of a material.

[Protective layer]
(Protective layer B1)
As the protective layer B1, a polyethylene terephthalate (PET) film (manufactured by SKC, trade name: SH34) having a thickness of 23 μm was prepared. When the toughness of the PET film was measured by the method described later, it was 140 mJ / mm ³ .

(Protective layer B2)
As the protective layer B2, a triacetyl cellulose (TAC) film having a thickness of 40 μm (manufactured by Konica Minolta Co., Ltd., trade name: KC4UAW) was prepared. When the toughness of the TAC film was measured by the method described later, it was 20 mJ / mm ³ .

(Protective layer B3)
As the protective layer B3, a triacetyl cellulose (TAC) film having a thickness of 60 μm (manufactured by Konica Minolta Co., Ltd., trade name: KC6UAW) was prepared. The toughness of the TAC film was measured by the method described below and found to be 18 mJ / mm ³ .

(Protective layer B4)
As the protective layer B4, a cyclic olefin resin (COP) film having a thickness of 40 μm (manufactured by Nippon Zeon Corporation, trade name: ZF-16) was prepared. When the toughness of the COP film was measured by the method described later, it was 4 mJ / mm ³ .

(Measurement of toughness)
The toughness of the protective layer was measured as follows in accordance with JIS K7161. A rectangular piece having a long side of 110 mm and a short side of 10 mm was cut out from the protective layer using a super cutter. Next, the upper and lower grippers of the tensile tester [Autograph AG-Xplus tester manufactured by Shimadzu Corporation] sandwich both ends of the small piece in the long side direction so that the gap between the grippers is 5 cm, and the temperature is 23 ° C. In an environment with a relative humidity of 55%, the pieces were pulled in the long side direction at a tensile speed of 4 mm / min. The toughness was calculated as the integral value of the stress-strain curve from the initial stage to the fracture.

[Polarizer]
(Polarizer C1)
The polarizing plate C1 was produced as follows. A photoalignment layer was formed on a triacetyl cellulose (TAC) film (thickness 25 μm). A composition containing a dichroic dye and a polymerizable liquid crystal compound was applied onto an alignment layer, and the polymerizable liquid crystal compound was oriented and cured to obtain a polarizer having a thickness of 2 μm. A resin composition containing polyvinyl alcohol and water was applied onto the polarizer so that the thickness after drying was 1.0 μm. The coating film was dried at a temperature of 80 ° C. for 3 minutes to form an overcoat layer. The following retardation laminates were bonded to the surface of the overcoat layer via an adhesive layer. The retardation laminate is composed of a λ / 4 plate (thickness 3 μm) / adhesive layer (thickness 5 μm) composed of a layer in which the polymerizable liquid crystal compound is cured and an orientation layer / a layer in which the polymerizable liquid crystal compound is cured and an orientation layer. It is composed of a positive C layer (thickness 3 μm) / base material layer. In this way, the polarizing plate C1 was produced. The polarizing plate C1 was a circular polarizing plate. The base material layer in the retardation laminate corresponds to the base material layer 51 shown in FIG. 2 used for forming the second retardation layer (positive C layer), and corresponds to the protective layer 201 shown in FIG. In the polarizing plate C1, the protective layer B1 was used as the base material layer 51.

(Polarizers C2 to C4)
As the base material layer 51, protective layers B2 to B4 were used instead of the protective layer B1, and polarizing plates C2 to C4 were produced in the same manner as the polarizing plate C1.

[Touch sensor panel]
(Touch sensor panel D1)
A touch sensor panel D1 having a length of 177 mm and a width of 105 mm was prepared in which a transparent conductive layer, a separation layer, an adhesive layer, and a base material layer were laminated in this order. The transparent conductive layer contained an ITO layer, and the separation layer contained a cured layer of an acrylic resin composition, and the total thickness of both was 7 μm.
The adhesive layer had a thickness of 2 μm. The base material layer was a polyethylene terephthalate film having a thickness of 20 μm, and the toughness was 69 mJ / mm ³ .

(Touch sensor panel D2)
A touch sensor panel D2 having a length of 177 mm and a width of 105 mm, in which the transparent conductive layer and the separation layer were laminated in this order, was prepared. The transparent conductive layer contained an ITO layer, and the separation layer contained a cured layer of an acrylic resin composition, and the total thickness of both was 7 μm.

[Lated layer]
A pressure-sensitive adhesive composition for forming a bonding layer was prepared at the ratio of each component shown in Table 1. This pressure-sensitive adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (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 a bonding layer. Then, another release-treated polyethylene terephthalate film (thickness 38 μm) was laminated on the bonded layer. Then, it was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 50% RH.

BA: Butyl acrylate EHA: 2-Ethylhexyl acrylate AA: Acrylic acid The following cross-linking agent and silane coupling agent were used.
Crosslinking agent: Coronate L (manufactured by Tosoh Corporation)
Silane coupling (SC) agent: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Adhesive sheet]
(Adhesive sheet E1)
(1) Preparation of Acrylic Polymer An acrylic polymer was prepared by copolymerizing 54 parts by mass of n-butyl acrylate, 45 parts by mass of 2-ethylhexyl acrylate and 1 part by mass of 4-hydroxybutyl acrylate. The weight average molecular weight (Mw) of this acrylic polymer was 800,000.

(2) Preparation of Adhesive Composition 100 parts by mass of the acrylic polymer obtained in the above step (solid content conversion value; the same applies hereinafter) and trimethylolpropane-modified xylylene diisocyanate as a thermal cross-linking agent (manufactured by Soken Kagaku Co., Ltd.) Product name "TD-75") 0.25 parts by mass and 3-glycidoxypropyltrimethoxysilane (manufactured by Shinetsu Chemical Industry Co., Ltd., product name "KBM403") 0.2 parts by mass as a silane coupling agent. A coating solution of the pressure-sensitive adhesive composition was obtained by mixing, stirring well, and diluting with methyl ethyl ketone. Table 2 shows each formulation (solid content conversion value) of the pressure-sensitive adhesive composition when the acrylic polymer is 100 parts by mass (solid content conversion value). The abbreviations and the like shown in Table 2 represent the following.
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate 4HBA: 4-hydroxybutyl acrylate

(3) Production of Adhesive Sheet E1 The coating solution of the obtained pressure-sensitive adhesive composition was applied to the peeling-treated surface of a light separator (manufactured by Lintec Corporation, product name "SP-PET752150") with a knife coater. Then, the coating layer was heat-treated at 90 ° C. for 1 minute to form a coating layer. Next, the coating layer on the light separator obtained above and the heavy separator (manufactured by Lintec Corporation, product name "SP-PET382120") are bonded so that the peeled surface of the separator is in contact with the coating layer. , 23 ° C., 50% RH for 7 days to form a pressure-sensitive adhesive sheet E1 having a pressure-sensitive adhesive layer having a thickness of 10 μm, that is, a light separator / pressure-sensitive adhesive layer (thickness: 10 μm) / heavy separator. An adhesive sheet E1 made of the above was produced. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet E1 is designated as the pressure-sensitive adhesive layer E1. Table 2 shows the measured storage elastic moduli of the adhesive sheet E1. The thickness and storage elastic modulus of the pressure-sensitive adhesive layer E1 are values measured by a method described later.

(Adhesive sheet E2)
Using the same coating solution of the pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E1, the structure of the light separator / pressure-sensitive adhesive layer (thickness: 25 μm) / heavy separator is formed by the same method as that of the pressure-sensitive adhesive sheet E1 except that only the coating thickness is different. An adhesive sheet E2 made of the above was prepared. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet E2 is referred to as the pressure-sensitive adhesive layer E2. Since the pressure-sensitive adhesive sheet E2 is manufactured using the same pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E1, its storage elastic modulus is the same value as that of the pressure-sensitive adhesive sheet E1.

(Adhesive sheet E3)
Using the same coating solution of the pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E1, the structure of the light separator / pressure-sensitive adhesive layer (thickness: 50 μm) / heavy separator is formed by the same method as that of the pressure-sensitive adhesive sheet E1 except that only the coating thickness is different. An adhesive sheet E3 made of the above was prepared. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet E3 is designated as the pressure-sensitive adhesive layer E3. Since the pressure-sensitive adhesive sheet E3 is manufactured using the same pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E1, its storage elastic modulus is the same as that of the pressure-sensitive adhesive sheet E1.

(Adhesive sheet E4)
(1) Preparation of Acrylic Polymer Acrylic polymer having a weight average molecular weight (Mw) shown in Table 2 was prepared by making the ratio of each monomer constituting the acrylic polymer the same as that of the pressure-sensitive adhesive sheet E1.

(2) Preparation of Adhesive Composition With 100 parts by mass of the acrylic polymer obtained in the above step and trimethylolpropane-modified xylylene diisocyanate (manufactured by Soken Kagaku Co., Ltd., product name "TD-75") as a thermal cross-linking agent. , 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name "KBM403") as a silane coupling agent was mixed at the blending ratio shown in Table 2, stirred well, and diluted with methyl ethyl ketone. A coating solution of the pressure-sensitive adhesive composition was obtained.

(3) Production of Adhesive Sheet E4 Using the coating solution of the obtained pressure-sensitive adhesive composition, a light separator / pressure-sensitive adhesive layer (thickness: 5 μm) was used in the same manner as the pressure-sensitive adhesive sheet E1 except that only the coating thickness was different. ) / A pressure-sensitive adhesive sheet E4 having a structure of a heavy separator was produced. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet E4 is referred to as the pressure-sensitive adhesive layer E4.
Table 2 shows the measured storage elastic moduli of the adhesive sheet E4. The thickness and storage elastic modulus of the pressure-sensitive adhesive layer E4 are values measured by a method described later.

(Adhesive sheet E5)
Using a coating solution of the same pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E4, a light separator / pressure-sensitive adhesive layer (thickness: 10 μm) / heavy separator was constructed by the same method as the pressure-sensitive adhesive sheet E1 except that only the coating thickness was different. An adhesive sheet E5 made of the above was prepared. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet E5 is designated as the pressure-sensitive adhesive layer E5. Since the pressure-sensitive adhesive sheet E5 is manufactured using the same pressure-sensitive adhesive composition as the pressure-sensitive adhesive sheet E4, its storage elastic modulus is the same value as that of the pressure-sensitive adhesive sheet E4.

(Measurement of thickness of adhesive layer)
The measurement was performed using a contact type film thickness measuring device (“MS-5C” manufactured by Nikon Corporation).

(Measurement of storage elastic modulus)
A sample in which the pressure-sensitive adhesive layer was laminated to a size of 150 μm was cut into a size of 5 mm × 30 mm, and using a rheometer (MCR-301, manufactured by Antonio Parr), the temperature was 25 °, the stress was 1%, and the frequency was 1 Hz. The storage elastic modulus in. The measurement results are shown in Table 2.

<Example 1>
The surface of one of the front plates A1 on the hard coat layer side, the surface of both the polarizing plate C1 and the surface of the touch sensor panel D1 on the transparent conductive layer side were subjected to corona treatment. The corona treatment was performed under the conditions of frequency: 20 kHz, voltage: 8.6 kV, power: 2.5 kW, and speed: 6 m / min. Then, each layer is laminated so as to be "front plate A1 / bonding layer / polarizing plate C1 / adhesive layer E1 / touch sensor panel D1 / adhesive layer E3", and bonded using a roll joining machine. , The optical laminate of Example 1 having the same configuration as the optical laminate 100 shown in FIG. 1 was obtained by curing in an autoclave. The obtained optical laminate was subjected to an impact resistance test and a bending resistance test. The results are shown in Table 3.

<Examples 2 to 7, Comparative Examples 1 and 2>
In Example 1, the same as in Example 1 except that the polarizing plate, the touch sensor panel, and the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer, second pressure-sensitive adhesive layer) used as shown in Table 3 was used. Optical laminates of Examples 2 to 7 and Comparative Examples 1 and 2 were obtained. The obtained optical laminate was subjected to an impact resistance test and a bending resistance test. The results are shown in Table 3.

<Impact resistance test>
From the optical laminates obtained in each Example and Comparative Example, a small piece having a rectangular size of 150 mm on the long side and 70 mm on the short side was cut out using a super cutter and formed into an acrylic plate via the second adhesive layer of the small piece. It was pasted together. Then, in an environment of 23 ° C. and 55% relative humidity, the evaluation pen is placed at a height of 10 cm from the outermost surface of the front plate of the small piece so that the pen tip is positioned and the pen tip faces downward. It was held and the evaluation pen was dropped from that position. The position of the pattern of the transparent conductive layer of the touch sensor panel was marked on the front plate of the small piece, and the evaluation pen was dropped so that the pen tip touched the position where the transparent conductive layer was arranged. As the evaluation pen, a pen having a weight of 11 g and a pen tip diameter of 0.7 mm was used. The small pieces after the evaluation pen was dropped were visually observed and the touch sensor panel function was confirmed, and the evaluation was performed according to the following criteria.
Table 3 shows the evaluation results.
A: No cracks. Touch sensor panel function maintenance.
B: There is a crack. Touch sensor panel function maintenance.
C: There is a crack. No touch sensor panel function.

<Bending resistance test>
The flexibility test was carried out at a temperature of 25 ° C. according to the following procedure. The optical laminates obtained in each Example and Comparative Example are installed in a bending tester (CFT-720C, manufactured by Covotech) in a flat state (not bent) so that the touch sensor panel side is on the inside. After bending the optical laminate so that the distance between the touch sensor panels facing each other would be 4.0 mm when the optical laminate was bent, a bending operation was performed to return the optical laminate to the original flat state. When this bending operation was performed once, the number of times of bending was counted as one, and this bending operation was repeated. The number of times of bending when cracks and / or floating of the adhesive layer occurred in the region bent by the bending operation was confirmed as the limit number of times of bending, and evaluated as follows. Table 3 shows the evaluation results.
A: Even if the number of bends reached 200,000, the limit number of bends was not reached,
B: The limit number of bends was reached when the number of bends was 100,000 or more and 200,000 or less.
C: The limit number of bends was reached when the number of bends was 50,000 or more and less than 100,000.
D: The limit number of bends was reached when the number of bends was less than 50,000.

10 front plate, 20 polarizing plate, 30 touch sensor panel, 31 transparent conductive layer, 32 base material layer, 41 first adhesive layer, 42 second adhesive layer, 43 bonded layer, 50, 55 retardation body, 51 , 56 base material layer, 52 alignment layer, 53 retardation layer, 200 polarizing layer, 201 protective layer.

Claims

An optical laminate including a front plate, a polarizing plate, a first adhesive layer, and a touch sensor panel in this order.
The polarizing plate is provided with a protective layer on the outermost surface on the side of the first pressure-sensitive adhesive layer.
An optical laminate satisfying the relationship of the following formula (1a), where the toughness is a [mJ / mm 3 ] and the thickness is b [μm] for the protective layer.
a × b ≧ 700 (1a)
A second adhesive layer provided on the surface of the touch sensor panel opposite to the first adhesive layer side is further provided.
Claim 1 satisfies the relationship of the following formulas (2a) and (3a), where t1 [μm] is the thickness of the first pressure-sensitive adhesive layer and t2 [μm] is the thickness of the second pressure-sensitive adhesive layer. The optical laminate according to the description.
t1 / t2 ≧ 0.1 (2a)
t1 / t2 ≦ 2 (3a)
The optical laminate according to claim 1 or 2, wherein the protective layer is provided with a retardation layer on a surface opposite to the first pressure-sensitive adhesive layer side.
The optical laminate according to claim 3, wherein the retardation layer contains a cured product of a polymerizable liquid crystal compound.
The optical laminate according to any one of claims 1 to 4, wherein the retardation layer is a positive C layer or a 1/4 wavelength layer.
The optical laminate according to any one of claims 1 to 5, wherein the touch sensor panel includes a base material layer and a transparent conductive layer provided on the base material layer.
A display device including the optical laminate according to any one of claims 1 to 6.