KR20220131157A - Optical laminate and display device - Google Patents

Abstract

The present invention relates to an optical laminate in which a first optical member serving as a front plate, a first pressure sensitive adhesive layer, a second optical member, and a second pressure sensitive adhesive layer are stacked by being in contact with each other in this order. When the yield stress of the second optical member is S2 [MPa], and the storage elastic modulus of the second pressure sensitive adhesive layer is G'2 [MPa], the relationship of formula (1): 46 <= S2/G'2 <= 17,500 is satisfied.

Description

Optical laminate and display device {OPTICAL LAMINATE AND DISPLAY DEVICE}

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

Korean Patent Application Laid-Open No. 2018-0012913 (Patent Document 1) describes providing a window for a display device having excellent durability.

In the window of the touch panel type display device, when writing, manipulation, drawing, etc. are performed by pressing the stylus pen, there is a problem that a dent (so-called plastic deformation) that does not return to its original state may occur. The present invention is an optical laminate that is disposed on the front surface of a display device and is used, even when a stylus pen is pressed, an optical laminate capable of suppressing occurrence of the depression, and a display device including the optical laminate aims to provide

This invention provides the optical laminated body and display apparatus illustrated below.

[1] An optical laminate in which a first optical member serving as a front plate, a first adhesive layer, a second optical member, and a second adhesive layer are laminated in contact with each other in this order,

When the yield stress of the second optical member is S ₂ [MPa] and the storage elastic modulus of the second pressure-sensitive adhesive layer is G′ ₂ [MPa], the following formula (1):

46 ≤ S ₂ /G' ₂ ≤ 17500 (1)

An optical laminate that satisfies the relationship of

[2] When the yield stress of the first optical member is S ₁ [MPa], the following formula (2):

70 MPa ≤ S ₁ ≤ 180 MPa (2)

The optical laminate according to [1], which satisfies the relationship of

[3] When the thickness of the first optical member is T ₁ [μm] and the thickness of the first pressure-sensitive adhesive layer is t ₁ [μm], the following formula (3):

1.5 ≤ T ₁ /t ₁ ≤ 5 (3)

The optical laminate according to [1] or [2], which satisfies the relationship of

[4] When the thickness of the first optical member is T ₁ [μm] and the thickness of the second pressure-sensitive adhesive layer is t ₂ [μm], the following formula (4):

1.5 ≤ T ₁ /t ₂ ≤ 5 (4)

The optical laminate according to any one of [1] to [3], which satisfies the relationship of

[5] The optical laminate according to any one of [1] to [4], wherein the surface of the first optical member opposite to the side of the first pressure-sensitive adhesive layer is constituted by a hard coat layer.

[6] The optical laminate according to any one of [1] to [5], which has a polarizing plate.

[7] The optical laminate according to any one of [1] to [6], which has a touch sensor panel.

[8] A display device comprising the optical laminate according to any one of [1] to [7].

ADVANTAGE OF THE INVENTION According to this invention, even if a stylus pen is used, the optical laminated body which can suppress that a depression arises, and the display apparatus containing the said optical laminated body can be provided.

It is a schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of the optical laminated body which concerns on this invention is described referring drawings, this invention is not limited to the following embodiment. In all the drawings below, scales are appropriately adjusted to facilitate understanding of each component, and the scale of each component shown in the drawings does not necessarily coincide with the scale of the actual component.

[Optical laminate]

The optical laminated body which concerns on this invention is an optical laminated body laminated|stacked by the 1st optical member which is a front plate, a 1st adhesive layer, a 2nd optical member, and a 2nd adhesive layer in this order. In the optical laminated body which concerns on this invention, n pieces (n is an integer greater than or equal to 1) optical members may be laminated|stacked on the surface on the opposite side to the surface of the side which contact|connects the 2nd optical member of a 2nd adhesive layer, and this In the specification, about these n optical members, from the side close|similar to a 2nd adhesive layer, 3rd optical member, 4th optical member... do it with Between the optical member and the optical member, it is preferable that the adhesive layer is laminated, and in this specification, the adhesive layer laminated|stacked on the opposite side to the front plate side of the x-th optical member (x is an integer of 3 or more), Let it be an x-th adhesive layer. n is preferably an integer of 4 or less, and more preferably an integer of 2 or less.

In the present specification, when simply referred to as an “optical member”, all of the first optical member, the second optical member, and the x-th optical member are applicable. Both the 2nd adhesive layer and the xth adhesive layer apply.

Each optical member may be comprised from one layer, or may be comprised from several layers. In this specification, with respect to the optical member which consists of a some layer, whether it is set as a some optical member or one optical member is judged based on the presence or absence of the adhesive layer 10 micrometers or more in thickness. In the present specification, two portions separated by a pressure-sensitive adhesive layer having a thickness of 10 μm or more are different optical members. Therefore, each optical member may contain the adhesive layer less than 10 micrometers in thickness, on the other hand, it does not contain the adhesive layer 10 micrometers or more in thickness.

The thickness of the optical laminate according to the present invention is not particularly limited because it varies depending on the functions required for the optical laminate and the use of the optical laminate, for example, 20 µm or more and 4000 µm or less, preferably 30 µm or more It is 2000 micrometers or less, More preferably, they are 50 micrometers or more and 1000 micrometers or less, and 100 micrometers or more may be sufficient.

The planar view shape of the optical laminate may be, for example, a square shape, preferably a rectangular shape having a long side and a short side, and more preferably a rectangle. When the shape of the surface direction of the optical laminated body 100 is a rectangle, the length of a long side may be 10 mm or more and 1400 mm or less, for example, Preferably they are 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. As for each layer which comprises the optical laminated body 100, each part may be R-processed, an edge part may be notched, or hole processing may be carried out.

The optical laminate is preferably bendable. Being bendable means that it can be bent without generating a crack. The optical laminate may be bendable with the first optical member side as at least either one of the inner side and the outer side, Preferably the first optical member side is bendable with the inner side, More preferably, the first optical member side It tends to be difficult to generate cracks even when repeated bending is performed so that the bending radius is 2 mm with In this specification, the bending|flexion includes the form of bending in which a curved surface is formed in a bending part. The form of bending WHEREIN: The radius of curvature of the bent inner surface is not specifically limited. Further, the bending includes a form of refraction in which the refraction angle of the inner surface is greater than 0° and less than 180°, and a form of folding in which the radius of curvature of the inner surface is close to zero or the refraction angle of the inner surface is 0°.

An optical laminated body can be used for a display apparatus etc., for example. 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 electroluminescence display device. The optical laminate 100 is particularly suitable for a flexible display device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the optical laminated body which concerns on one Embodiment of this invention. As for the optical laminated body 100 shown in FIG. 1, the 1st optical member 10 which is a front plate, the 1st adhesive layer 31, the 2nd optical member 22, and the 2nd adhesive layer 32 are Two (n=2) optical members are laminated on the surface opposite to the surface of the second adhesive layer 32 on the side in contact with the second optical member 22 and laminated in this order. . On the surface on the opposite side to the surface on the side in contact with the 2nd optical member 22 of the 2nd adhesive layer 32, the 3rd optical member 23, the 3rd adhesive layer 33, and the 4th optical member 24 ) are stacked in contact with each other in this order. All of the 1st - 3rd adhesive layers 31, 32, 33 have a thickness of 10 micrometers or more.

In the optical laminate 100 , the first optical member 10 includes a base material 11 , and a hard coating layer ( 12) is further included. For example, in the optical laminate 100, the 2nd optical member 22 is a protective plate, the 3rd optical member 23 is a polarizing plate, and the 4th optical member 24 is a touch sensor panel.

<Formula (1)>

In the optical laminate according to the present invention, when the yield stress of the second optical member is S ₂ [MPa] and the storage elastic modulus of the second pressure-sensitive adhesive layer is G′ ₂ [MPa], the following formula (1):

46 ≤ S ₂ /G' ₂ ≤ 17500 (1)

satisfy the relationship of

As for the optical laminated body which concerns on this invention, when a 2nd optical member and a 2nd adhesive layer satisfy|fill the relationship of said Formula (1), even if a stylus pen is pressed on the 1st optical member, it is hard to produce plastic deformation.

Since the first optical member is used as the front plate, a hard material is used so as to be able to withstand an impact from the outside. However, since a hard material has a weak restoring force, the front plate is generally prone to plastic deformation. Then, by selecting the material of the physical property of the said range as the 2nd optical member in a position close to the 1st optical member, and a 2nd adhesive, when the restoring force is raised as a whole optical laminated body, it is thought that a plastic deformation can be made difficult to occur.

In this specification, the yield stress of an optical member and the storage elastic modulus of an adhesive layer can be measured according to the method as described in the Example mentioned later. The yield stress of an optical member changes with the material of an optical member, and even if it is the same material, it changes with thickness. The elastic modulus of the pressure-sensitive adhesive layer varies depending on the material.

The yield stress of the second optical member is, for example, 40 to 250 [MPa], preferably 40 to 200 [MPa]. The storage elastic modulus of a 2nd adhesive layer is 0.01-1.8 [MPa], for example, Preferably it is 0.01-1.5 [MPa].

It is preferable that a 2nd optical member has a higher yield stress than a 1st optical member.

Therefore, the value of S2/G'2 in Formula ( ₁ ) can be adjusted by adjusting suitably the material, thickness, the material of a _2nd adhesive layer, etc. of a 2nd optical member.

The present inventors need to provide the function of protecting an optical laminated body as a front plate about the 1st optical member which is a front plate, and while the range which can adjust a physical property is limited, a 2nd optical member and a 2nd adhesive By adjusting the physical properties of the layer and adjusting so that the value of S ₂ /G' ₂ satisfies the relationship of Formula (1), the knowledge that a configuration in which depression does not easily occur even if a stylus pen is used is obtained. In this specification, the thing which a dent is hard to generate|occur|produce includes the thing which a dent is hard to produce, and a thing which is easy to disappear even if a dent occurs. The optical laminate according to the present invention, from the viewpoint of further improving the difficulty of denting, preferably the following formula (1a):

50 ≤ S ₂ /G' ₂ ≤ 14000 (1a)

satisfy the relationship of

<First optical member>

The first optical member is a front plate and can constitute the outermost surface of the display device. As long as a 1st optical member is a plate-shaped object which can transmit light, a material and thickness will not be limited. As long as the 1st optical member contains a base material, it may be comprised only with a base material, or may be comprised from a base material and another layer. The base material and the other layer may be comprised only by one layer, respectively, and may be comprised by two or more layers. As a base material contained in the 1st optical member, a resin plate-shaped object (for example, a resin plate, a resin sheet, a resin film, etc.), a glass-made plate-shaped object (for example, a glass plate, a glass film, etc.), a resin plate-shaped object and a laminate of a plate-like body made of glass.

When the yield stress of the first optical member is S ₁ [MPa], from the viewpoint of facilitating an optical laminate having excellent impact resistance, preferably the following formula (2):

70 MPa ≤ S ₁ ≤ 180 MPa (2)

satisfies the relationship of, more preferably the following formula (2a):

80 MPa ≤ S ₁ ≤ 170 MPa (2a)

satisfy the relationship of

When the thickness of the first optical member is T ₁ [μm], T ₁ may be, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 20 μm or more. It is 100 micrometers or less, and 50 micrometers or more may be sufficient. It is preferable that thickness T1 of a _1st optical member is 40 micrometers or more from a viewpoint of being easy to comprise the optical laminated body which has the outstanding impact resistance. In this invention, the thickness of each layer which comprises an optical laminated body can be measured according to the measuring method of the thickness demonstrated in the Example mentioned later.

When the base material of a 1st optical member is a resin plate-shaped object, what has a hard-coat layer may be sufficient. When a 1st optical member has a hard-coat layer, hardness can be improved more by providing a hard-coat layer in at least one surface of a laminated body. The hard-coat layer may be formed in one surface of a base material, and may be formed in both surfaces. As for the 1st optical member, it is preferable that the surface on the opposite side to the 1st adhesive layer side is comprised by the hard-coat layer. When the display apparatus in which an optical laminated body is arrange|positioned is a display apparatus of a touchscreen system, since the surface of a 1st optical member turns into a touch surface, the 1st optical member which has a hard-coat layer is used preferably. By providing a hard-coat layer, hardness and scratch resistance can be improved. The hard coat layer is, for example, a cured layer of ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The hard-coat layer may contain the additive in order to improve hardness. The additive is not limited, and inorganic fine particles, organic fine particles, or a mixture thereof may be mentioned.

The thickness of a hard-coat layer may be 0.1 micrometer or more and 30 micrometers or less, for example, Preferably they are 1 micrometer or more and 20 micrometers or less, More preferably, they are 5 micrometers or more and 15 micrometers or less.

It is also preferable that an abrasion-resistant layer is formed on the visual recognition side of a hard-coat layer in order to improve abrasion resistance or prevent contamination by sebum etc. The first optical member may have an abrasion-resistant layer, and the abrasion-resistant layer may be a layer constituting a surface of the front panel on the viewer side. The wear-resistant layer may include a structure derived from a fluorine compound. As a fluorine compound, it has a silicon atom, and the compound which has a hydrolysable group like an alkoxy group and a halogen in a silicon atom is preferable. A coating film can be formed by a hydrolysable group dehydration-condensation reaction, and the adhesiveness of an abrasion-resistant layer can be improved by reacting with active hydrogen on the surface of a base material. Moreover, since a fluorine compound can provide water repellency when it has a perfluoroalkyl group or a perfluoropolyether structure, it is preferable. Particularly preferred are fluorine-containing polyorganosiloxane compounds having a perfluoropolyether structure and a long-chain alkyl group having 4 or more carbon atoms. It is also preferable to use two or more types of compounds as a fluorine compound. Further, preferred fluorine compounds to be included are fluorine-containing organosiloxane compounds containing an alkylene group having 2 or more carbon atoms and a perfluoroalkylene group.

The thickness of the wear-resistant layer is, for example, 1 nm or more and 20 nm or less. Moreover, the abrasion-resistant layer has water repellency, and a water contact angle is about 110-125 degrees, for example. The contact angle hysteresis and the sliding angle measured by the sliding method are about 3 to 20 degrees and about 2 to 55 degrees, respectively. In addition, the wear-resistant layer is a silanol condensation catalyst, antioxidant, rust inhibitor, ultraviolet absorber, light stabilizer, fungicide, antibacterial agent, bioadhesion inhibitor, deodorant, pigment, flame retardant, antistatic agent, in the range that does not impair the effects of the present invention. You may contain various additives, such as an inhibitor.

A primer layer may be provided between the abrasion-resistant layer and the hard coat layer. As a primer agent, there exist primer agents, such as an epoxy compound of an ultraviolet curing type, a thermosetting type, a moisture curing type, or a two-component curing type, for example. Moreover, as a primer agent, a polyamic acid may be used and it is also preferable to use a silane coupling agent. The thickness of the primer layer is, for example, 0.001 to 2 µm.

As a method of obtaining a laminate comprising an abrasion-resistant layer and a hard coat layer, a primer layer is formed by applying, drying, and curing a primer agent as necessary on the hard coat layer, followed by a composition containing a fluorine compound (abrasion-resistant layer). It can be formed by apply|coating and drying the composition for coating. Examples of the coating method include a dip coating method, a roll coating method, a bar coating method, a spin coating method, a spray coating method, a die coating method, and a gravure coating method. Moreover, it is also preferable to perform hydrophilization treatment, such as plasma treatment, corona treatment, or ultraviolet treatment, to an applied surface before apply|coating a primer agent or the composition for abrasion-resistant layer coating.

As a resin film used as a base material, if it is a resin film which can transmit light, it will not be limited. For example, triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, polystyrene, polyamide, polyetherimide, poly(meth)acryl , polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polymethyl (meth ) acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and a film formed of a polymer such as polyamideimide. These polymer|macromolecule can be used individually or in mixture of 2 or more types. When the laminate is used for a flexible display, a resin film formed of a polymer such as polyimide, polyamide, polyamideimide, etc., which has excellent flexibility, can be configured to have high strength and high transparency, is preferable. used In addition, in this specification, "(meth)acryl" means that either an acryl or methacryl may be sufficient. "(meth)", such as (meth)acrylate, has the same meaning. The thickness of the resin film is, for example, 10 µm or more and 500 µm or less, and preferably 20 µm or more and 100 µm or less.

When the base material of a 1st optical member is a glass plate, the tempered glass for displays is used preferably for a glass plate. The thickness of a glass plate may be 10 micrometers or more and 1000 micrometers or less, for example, and 20 micrometers or more may be sufficient as it. By using a glass plate, the front plate which has the outstanding mechanical strength and surface hardness can be comprised.

When the optical laminate is used for a display device, the first optical member not only has a function (function as a window film) to protect the front surface (screen) of the display device, but also functions as a touch sensor, blue light cut function, viewing angle adjustment What has a function etc. may be sufficient.

<Adhesive layer>

A 1st adhesive layer is interposed between a 1st optical member and a 2nd optical member, and bonds these together. The 2nd adhesive layer is laminated|stacked on the surface on the opposite side to the 1st optical member side (front board side) of a 2nd optical member. The x-th adhesive layer is laminated|stacked on the surface on the opposite side to the 1st optical member side (front board side) of the x-th optical member. An adhesive layer may consist of one layer as long as thickness is 10 micrometers or more, Although it may consist of two or more layers, Preferably, it consists of one layer. Each pressure-sensitive adhesive layer may be the same as or different from each other in the composition, compounding component, thickness, etc. of the pressure-sensitive adhesive composition.

The thickness of an adhesive layer is 10 micrometers or more, Preferably it is 12 micrometers or more, More preferably, it is 100 micrometers or less, More preferably, it is 50 micrometers or less.

When the thickness of the first pressure-sensitive adhesive layer is t ₁ [μm], from the viewpoint of suppressing the dent temporarily caused by pressing the stylus pen, in relation to the thickness T ₁ [μm] of the first optical member, Equation (3):

1.5 ≤ T ₁ /t ₁ ≤ 5 (3)

It is desirable to satisfy the relationship of

The storage elastic modulus of a 1st adhesive layer is 0.01-1.8 [MPa], for example, Preferably it is 0.01-1.5 [MPa].

When the thickness of the second pressure-sensitive adhesive layer is t ₂ [μm], from the viewpoint of suppressing the dent temporarily caused by pressing the stylus pen, in relation to the thickness T ₁ [μm] of the first optical member, Equation (4):

1.5 ≤ T ₁ /t ₂ ≤ 5 (4)

It is desirable to satisfy the relationship of

When the thickness of the x-th pressure-sensitive adhesive layer is t _x [μm], from the viewpoint of suppressing the depression caused by pressing of the stylus pen, in relation to the thickness T ₁ [μm] of the first optical member, the following formula (5):

1.5 ≤ T ₁ /t _x ≤ 5 (5)

It is desirable to satisfy the relationship of

The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition containing (meth)acrylic resin, rubber-based resin, urethane-based resin, ester-based resin, silicone-based resin, and polyvinyl ether-based resin as a main component (base polymer). As an adhesive composition which comprises an adhesive layer, the adhesive composition which uses as a base polymer (meth)acrylic-type resin excellent in transparency, weather resistance, heat resistance, etc. is preferable. An active energy ray hardening type or a thermosetting type may be sufficient as an adhesive composition.

As the (meth)acrylic resin used in the pressure-sensitive adhesive composition, (meth)acrylic acid ester, such as (meth)butyl acrylate, (meth)ethyl acrylate, (meth)acrylate isooctyl, (meth)acrylic acid 2-ethylhexyl, or The polymer or copolymer which uses 2 or more types as a monomer is used preferably. It is preferable to copolymerize a polar monomer with a base polymer. As the polar monomer, (meth)acrylic acid compound, (meth)acrylic acid 2-hydroxypropyl compound, (meth)acrylic acid hydroxyethyl compound, (meth)acrylamide compound, N,N-dimethylaminoethyl (meth)acrylate compound and monomers having a carboxy group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as a glycidyl (meth)acrylate compound.

Although the adhesive composition may contain only the said base polymer, normally, it further contains a crosslinking agent. Examples of the crosslinking agent include a metal ion having a divalent or higher valence, which forms a carboxylate metal salt with a carboxyl group, a polyamine compound that forms an amide bond with a carboxyl group, a polyepoxy compound that forms an ester bond with a carboxyl group, or A polyisocyanate compound which forms an amide bond between a polyol and a carboxy group is illustrated. The crosslinking agent is preferably a polyisocyanate compound.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with an active energy ray such as an ultraviolet ray or an electron beam, has adhesiveness even before irradiation with an active energy ray, and can be adhered to an adherend such as a film, and can be irradiated with an active energy ray It has the property of being able to adjust the adhesion by being cured by It is preferable that an active energy ray hardening-type adhesive composition is an ultraviolet curable type. In addition to a base polymer and a crosslinking agent, an active energy ray hardening-type adhesive composition contains an active energy ray polymeric compound further. You may contain a photoinitiator, a photosensitizer, etc. as needed.

As an active energy ray polymeric compound, For example, the (meth)acrylate monomer which has at least 1 piece(s) acryloyloxy group in a molecule|numerator; (meth)acrylic compounds such as (meth)acryloyloxy group-containing compounds such as (meth)acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyloxy groups in the molecule , and compounds having at least two benzoylphenylmethacryloyl groups in the molecule. The pressure-sensitive adhesive composition may contain 0.1 parts by mass or more of the active energy ray polymerizable compound with respect to 100 parts by mass of the solid content of the pressure-sensitive adhesive composition, and may contain 10 parts by mass or less, 5 parts by mass or less, or 2 parts by mass or less.

A benzoylphenyl methacryloyl group means group represented by the following structures. * indicates the number of bonds. The number of the benzoylphenyl methacryloyl groups which an active energy ray-polymerizable compound has in a molecule|numerator may be 5 or less, and may be 4 or less.

As a compound which has at least two benzoylphenylmethacryloyl groups in a molecule|numerator, the following compound is mentioned, for example.

As a photoinitiator, benzophenone, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone etc. are mentioned, for example. A photoinitiator may contain 1 type or 2 or more types. When an adhesive composition contains a photoinitiator, 0.01 mass part or more and 3.0 mass parts or less may be sufficient as the total content with respect to 100 mass parts of solid content of an adhesive composition, for example.

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, tackifiers, fillers (metal powders and other inorganic powders, etc.), antioxidants, ultraviolet rays It may contain additives such as absorbents, dyes, pigments, colorants, defoamers, corrosion inhibitors, and photopolymerization initiators.

An adhesive layer can be formed by apply|coating the organic solvent dilution liquid of the said adhesive composition on a base material, and drying it. An adhesive layer can also be formed using the adhesive sheet formed using the adhesive composition. When an active energy ray hardening-type adhesive composition is used, it can be set as the adhesive layer which has a desired degree of hardening by irradiating an active energy ray to the formed adhesive layer.

<Optical member>

As an optical member in an optical laminated body, a front plate (1st optical member), a guard plate, a polarizing plate, a touch sensor panel, etc. other than that, a back plate etc. are illustrated, for example. As a back plate, a touch sensor panel, an organic electroluminescent display element, etc. are mentioned. When an optical member is comprised from several layers, the bonding layer for bonding two layers can be included. As a lamination order of the optical member in an optical laminated body, front plate (1st optical member)/guard plate/polarizing plate/touch sensor panel, front plate (1st optical member)/guard plate/polarizing plate/touch sensor panel, for example /Organic EL display element, front plate (1st optical member)/guard plate/touch sensor panel/polarizing plate, front plate (1st optical member)/guard plate/touch sensor panel/polarizing plate/organic EL display element etc. are mentioned. It is preferable that the polarizing plate in the lamination|stacking procedure shown here is a circularly polarizing plate at the point which can provide the function as an antireflection film to an optical laminated body. The guard plate in the lamination procedure shown here may not be included, and is included from the viewpoint of easy adjustment of the yield stress S ₂ of the second optical member to a desired value by using the guard plate as the second optical member. it is preferable

≪Polarizer≫

The polarizing plate may be, for example, a linear polarizing plate, a circularly polarizing plate (including an elliptically polarizing plate) or the like. The circularly polarizing plate includes a linearly polarizing plate and a retardation layer. Since a circularly polarizing plate can absorb the external light reflected in an image display apparatus, it can provide the function as an antireflection film to an optical laminated body.

The thickness of a polarizing plate is 5 micrometers or more normally, 20 micrometers or more may be sufficient, 25 micrometers or more may be sufficient, and 30 micrometers or more may be sufficient as it. Moreover, it is preferable that it is 80 micrometers or less, and, as for the thickness of a polarizing plate, it is more preferable that it is 60 micrometers or less.

≪Straight polarizing plate≫

The linear polarizing plate has a function of selectively transmitting linearly polarized light in any one direction from non-polarized light rays such as natural light. The linear polarizing plate includes a stretched film or stretched layer to which a dichroic dye is adsorbed, a cured product of a polymerizable liquid crystal compound, and a dichroic dye, and the dichroic dye is dispersed in the cured product of the polymerizable liquid crystal compound and is aligned. A layer etc. can be provided as a polarizer layer. The dichroic dye refers to a dye having a property in which the absorbance in the long-axis direction of the molecule differs from the absorbance in the short-axis direction. The linear polarizing plate using the liquid crystal layer as a polarizer layer is preferable since there is no restriction|limiting in a bending direction compared with the stretched film or stretched layer which made the dichroic dye adsorb|suck.

(Stretched film or polarizer layer which is a stretched layer to which a dichroic dye is adsorbed)

The polarizer layer, which is a stretched film to which a dichroic dye is adsorbed, is usually a step of uniaxially stretching a polyvinyl alcohol-based resin film, and dyeing a polyvinyl alcohol-based resin film with a dichroic dye such as iodine, thereby adsorbing the dichroic dye. It can be manufactured through the process of making the polyvinyl alcohol-type resin film to which the dichroic dye adsorb|sucks adsorb|suck into it, the process of treating with boric acid aqueous solution, and the process of washing with water after treatment with boric acid aqueous solution.

The thickness of a polarizer layer is 30 micrometers or less normally, Preferably it is 18 micrometers or less, More preferably, it is 15 micrometers or less. Making the thickness of a polarizer layer thin is advantageous for thinning of a polarizing plate. The thickness of a polarizer layer is 1 micrometer or more normally, for example, 5 micrometers or more may be sufficient.

Polyvinyl alcohol-type resin is obtained by saponifying polyvinyl acetate-type resin. As polyvinyl acetate-type resin, the copolymer of vinyl acetate and other monomer copolymerizable to it other than polyvinyl acetate which is a homopolymer of vinyl acetate is used. As another monomer copolymerizable with vinyl acetate, an unsaturated carboxylic acid type compound, an olefin type compound, a vinyl ether type compound, an unsaturated sulfone type compound, and the (meth)acrylamide type compound which has an ammonium group are mentioned, for example.

The saponification degree of polyvinyl alcohol-type resin is about 85 mol% or more and 100 mol% or less normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-type resin may be modified|denatured, and polyvinyl formal, polyvinyl acetal, etc. which were modified|denatured with aldehydes can also be used. The polymerization degree of polyvinyl alcohol-type resin is 1000 or more and 10000 or less normally, Preferably they are 1500 or more and 5000 or less.

The polarizer layer, which is a stretched layer to which the dichroic dye is adsorbed, is usually a process of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, a process of uniaxially stretching the obtained laminated film, a uniaxially stretched laminated film By dyeing the polyvinyl alcohol-based resin layer with a dichroic dye, the dichroic dye is adsorbed to form a polarizer layer; It can be manufactured through the following process. You may use the base film used in order to form a polarizer layer as a protective layer of a polarizer layer. You may peel and remove a base film from a polarizer layer as needed. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film mentioned later.

The polarizer layer which is the stretched film or stretched layer to which the dichroic dye was adsorbed may be used as a linear polarizing plate as it is, and may form a protective layer on the single side|surface or both surfaces, and may use it as a linear polarizing plate. As a protective layer, the thermoplastic resin film mentioned later can be used. The thickness of the linear polarizing plate obtained becomes like this. Preferably they are 2 micrometers or more and 40 micrometers or less.

The thermoplastic resin film is, for example, a cyclopolyolefin-based resin film; Cellulose acetate-type resin film which consists of resin, such as a triacetyl cellulose and a diacetyl cellulose; a polyester-based resin film made of a resin such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate-based resin film; (meth)acrylic resin film; Well-known films in the art, such as a polypropylene resin film, are mentioned. A polarizer layer and a protective layer can be laminated|stacked through the bonding layer mentioned later.

The thickness of the thermoplastic resin film is usually 100 µm or less, preferably 80 µm or less, more preferably 60 µm or less, still more preferably 40 µm or less, and still more preferably 30 µm or less from the viewpoint of reducing the thickness of the thermoplastic resin film. It is micrometer or less, and is 5 micrometers or more normally, Preferably it is 10 micrometers or more.

The hard-coat layer may be formed on the thermoplastic resin film. The hard-coat layer may be formed in one surface of a thermoplastic resin film, and may be formed in both surfaces. By providing a hard-coat layer, it can be set as the thermoplastic resin film which improved hardness and scratch property. A hard-coat layer can be carried out similarly to the hard-coat layer formed in the resin film mentioned above, and can be formed.

(a polarizer layer that is a liquid crystal layer)

The polymerizable liquid crystal compound used to form the liquid crystal layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. A polymerizable reactive group is a group which participates in a polymerization reaction, and it is preferable that it is a photopolymerizable reactive group. The photopolymerization reactive group refers to a group capable of participating in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. . Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The kind of polymerizable liquid crystal compound is not specifically limited, A rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and these mixtures can be used. The liquid crystallinity of the polymerizable liquid crystal compound may be either a thermotropic liquid crystal or a lyotropic liquid crystal, and may be a nematic liquid crystal or a smectic liquid crystal as a normal-order structure.

As a dichroic dye used for the polarizer layer which is a liquid crystal layer, it is preferable to have an absorption maximum wavelength (λMAX) in the range of 300-700 nm. As such a dichroic dye, although an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye, etc. are mentioned, for example, Especially, an azo dye is preferable. As an azo dye, a monoazo dye, a bisazo dye, a trisazo dye, a tetrakis azo dye, a stilbenazo dye, etc. are mentioned, Preferably they are a bisazo dye and a trisazo dye. Although a dichroic dye may be individual or may combine 2 or more types, it is preferable to combine 3 or more types. In particular, it is more preferable to combine three or more types of azo compounds. A part of the dichroic dye may have a reactive group, and may have liquid crystallinity.

The polarizer layer, which is a liquid crystal layer, is formed by, for example, applying a composition for forming a polarizer layer including a polymerizable liquid crystal compound and a dichroic dye on an alignment film formed on a base film, and polymerizing and curing the polymerizable liquid crystal compound. can do. On a base film, you may form a polarizer layer by apply|coating the composition for polarizer layer formation, forming a coating film, and extending|stretching this coating film with a base film. You may use the base film used in order to form a polarizer layer as a protective layer of a polarizer layer. The material and thickness of the base film may be the same as the material and thickness of the above-described thermoplastic resin film.

As a composition for forming a polarizer layer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a polarizer layer using the composition, Japanese Patent Laid-Open Nos. 2013-37353, 2013-33249, and Japanese Patent Laid-Open What is described in the 2017-83843 publication and the like can be exemplified. The composition for polarizer layer formation may further contain additives, such as a solvent, a polymerization initiator, a crosslinking agent, a leveling agent, antioxidant, a plasticizer, and a sensitizer, in addition to a polymerizable liquid crystal compound and a dichroic dye. These components may use only 1 type, respectively, and may use them in combination of 2 or more type.

The polymerization initiator which may be contained in the composition for forming a polarizer layer is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound, and a photopolymerization initiator is preferable from the viewpoint of being able to initiate a polymerization reaction under lower temperature conditions. . Specifically, a photoinitiator capable of generating an active radical or an acid by the action of light is exemplified, and among these, a photoinitiator capable of generating a radical by the action of light is preferable. To [ content of a polymerization initiator / 100 weight part of total amounts of a polymeric liquid crystal compound ], Preferably they are 1 mass part or more and 10 mass parts or less, More preferably, they are 3 mass parts or more and 8 mass parts or less. If it exists in this range, reaction of a polymeric group will fully advance and it will be easy to stabilize the orientation state of a liquid crystal compound.

The thickness of the polarizer layer which is a liquid crystal layer is 10 micrometers or less normally, Preferably they are 0.5 micrometer or more and 8 micrometers or less, More preferably, they are 1 micrometer or more and 5 micrometers or less.

The polarizer layer which is a liquid crystal layer may be used as a linear polarizing plate, without peeling and removing a base film, and it is good also as a linear polarizing plate by peeling and removing a base film from a polarizer layer. The polarizer layer which is a liquid crystal layer may form a protective layer on the single side|surface or both surfaces, and may use it as a linear polarizing plate. As a protective layer, the above-mentioned thermoplastic resin film can be used.

The polarizer layer which is a liquid crystal layer may have an overcoat layer on the single side|surface or both surfaces of a polarizer layer for the purpose of protection of a polarizer layer, etc. The overcoat layer can be formed, for example, by applying a material (composition) for forming an overcoat layer on the polarizer layer. Examples of the material constituting the overcoat layer include a photocurable resin and a water-soluble polymer. As a material constituting the overcoat layer, (meth)acrylic resin, polyvinyl alcohol-based resin, or the like can be used.

(retardation layer)

One layer may be sufficient as the retardation layer contained in a polarizing plate, and two or more layers may be sufficient as it. It is preferable that the retardation layer is laminated|stacked on the surface of the opposite side to the front plate side of a polarizer layer. The retardation layer may have an overcoat layer for protecting the surface, a base film for supporting the retardation layer, or the like. The retardation layer may include a λ/4 layer, and may include at least either a λ/2 layer or a positive C layer. When the retardation layer contains the λ/2 layer, the λ/2 layer and the λ/4 layer are sequentially laminated from the linear polarizing plate side. When the retardation layer contains the positive C layer, the λ/4 layer and the positive C layer may be sequentially laminated from the linear polarizing plate side, or the positive C layer and the λ/4 layer may be laminated sequentially from the linear polarizing plate side. The thickness of the retardation layer 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 may be formed from the resin film exemplified as the material of the protective layer, or may be formed from a layer in which a polymerizable liquid crystal compound is cured. The retardation layer may further include an alignment film. The retardation layer may have a bonding layer for bonding the λ/4 layer, the λ/2 layer, and the positive C layer.

When the retardation layer is formed by curing the polymerizable liquid crystal compound, the retardation layer can be formed by applying a composition containing the polymerizable liquid crystal compound to a base film and curing the composition. You may provide an orientation layer between a base film and an application layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film. When forming a retardation layer from the layer formed by hardening|curing a polymeric liquid crystal compound, the retardation layer may be knitted together in the optical laminated body in the form which has an orientation layer and a base film. A phase difference layer can be bonded together with a linear polarizing plate via a bonding layer.

≪Touch sensor panel≫

The touch sensor panel may be a sensor capable of detecting a touched position from the front side, or a sensor capable of detecting an operation made with a stylus pen from the front surface or a press such as writing, and may have a transparent conductive layer. A touch sensor panel can have a base material which supports this in addition to a transparent conductive layer. The detection method is not limited, and a touch sensor panel such as a resistive film method, a capacitive method, an optical sensor method, an ultrasonic method, an electromagnetic inductive coupling method, and a surface acoustic wave method is exemplified. Among them, a capacitive touch sensor panel is preferably used from the viewpoint of low cost, fast response speed, and thin film formation. A touch sensor panel may provide an adhesive layer, a separation layer, a protective layer, etc. between a transparent conductive layer and the base material which supports this. As an adhesive layer, an adhesive bond layer and an adhesive layer are mentioned. As a base material which supports a transparent conductive layer, the base material by which the transparent conductive layer is vapor-deposited on one surface, the base material to which the transparent conductive layer was transcribe|transferred through the adhesive layer, etc. are mentioned.

An example of the capacitive touch sensor panel is comprised by the base material, the transparent conductive layer for position detection provided on the surface of the base material, and a touch position detection circuit. In a display device provided with an optical laminate including a capacitive touch sensor panel, when the surface of the front plate is touched, the transparent conductive layer is grounded through the human body's capacitance at the touched point. 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 spaced apart from each other, a more detailed position can be detected.

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

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

The protective layer can be provided in contact with the transparent conductive layer to protect the conductive layer. The protective layer includes 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.

A touch sensor panel can be manufactured as follows, for example. In the first method, first, a substrate is laminated on a glass substrate through an adhesive layer. On the substrate, a patterned transparent conductive layer is formed by photolithography. By controlling temperature, a glass substrate and a base material are isolate|separated, and the touch sensor panel which consists of a transparent conductive layer and a base material is obtained.

In the second method, first, a separation layer is formed on a glass substrate, and, if necessary, a protective layer is formed on the separation layer. On the separation layer (or protective layer), a patterned transparent conductive layer is formed by photolithography. A peelable protective film is laminated|stacked on a transparent conductive layer, from a transparent conductive layer to a separation layer is transcribe|transferred, and a glass substrate is isolate|separated. The touch sensor panel which has a transparent conductive layer, a separation layer, an adhesive layer, and a base material in this order is obtained by bonding a base material and a separation layer together through an adhesive layer, and peeling a peelable protective film.

As the base material of the touch sensor panel, triacetyl cellulose, polyethylene terephthalate, cycloolefin polymer, polyethylene naphthalate, polyolefin, polycycloolefin, polycarbonate, polyethersulfone, polyarylate, polyimide, polyamide, polystyrene, polynor Resin films, such as bornene, are mentioned. From a viewpoint of being easy to comprise the base material layer which has desired toughness, polyethylene terephthalate is used preferably.

It is preferable that the thickness of a touch sensor panel is 30 micrometers or more from a viewpoint of being easy to comprise the optical laminated body which has the outstanding impact resistance. The thickness of a touch sensor panel is 100 micrometers or less, for example.

≪Backboard≫

As a back plate, the plate-shaped body which can transmit light, the component used for a normal display apparatus, etc. can be used.

The thickness of the back plate may be, for example, 5 µm or more and 2000 µm or less, preferably 10 µm or more and 1000 µm or less, and more preferably 15 µm or more and 500 µm or less.

As a plate-shaped object used for a back plate, it may be comprised with only one layer, and may be comprised with two or more layers, and what was illustrated about the plate-shaped object described in the front plate can be used.

As a component used for the normal display apparatus used for a back plate, the touch sensor panel mentioned above, organic electroluminescent display element, etc. are mentioned, for example.

≪Protection plate≫

As the guard plate, a resin-made plate that can transmit light, a component used in a normal display device, or the like can be used. The resin-made plate may be constituted by only one layer or may be constituted by two or more layers, and those exemplified for the resin-made plate described in the front plate may be used. Preferably, polymethyl (meth)acrylate, polyethylene terephthalate, polyamideimide, polyimide, etc. are mentioned.

The thickness of a guard plate may be 5 micrometers or more and 2000 micrometers or less, for example, Preferably they are 10 micrometers or more and 1000 micrometers or less, More preferably, they are 15 micrometers or more and 500 micrometers or less, More preferably, they are 30 micrometers or more and 100 micrometers or less. to be.

(bonding layer)

An optical member can contain the bonding layer for bonding two layers together. A bonding layer is a layer comprised from an adhesive or an adhesive agent. When a bonding layer is an adhesive layer, the thickness is less than 10 micrometers. The adhesive composition demonstrated by the x-th adhesive layer mentioned above can be used for the adhesive used as the material of a bonding layer.

As an adhesive agent used as the material of a bonding layer, it can form, for example combining 1 type, or 2 or more types among a water-system adhesive agent, an active energy ray hardening-type adhesive agent, etc. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, a water-based two-part type urethane-based emulsion adhesive, and the like. An active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, for example, an adhesive containing a polymerizable compound and a photopolymerization initiator, an adhesive containing a photoreactive resin, a binder resin, and a photoreactive crosslinking agent and adhesives containing Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers and photocurable urethane monomers, and oligomers derived from these monomers. As said photoinitiator, the compound containing the substance which irradiates active energy rays, such as an ultraviolet-ray, generates active species, such as a neutral radical, an anion radical, and a cationic radical, is mentioned.

The thickness of the bonding layer may be, for example, 1 µm or more, preferably 1 µm or more and less than 10 µm, more preferably 2 µm or more and less than 10 µm, still more preferably 2.5 µm or more and 5 µm or less.

The two opposing surfaces bonded together through a bonding layer may perform corona treatment, a plasma treatment, a flame treatment, etc. beforehand, and may have a primer layer etc.

[Method for producing optical laminate]

An optical laminated body can be manufactured according to the method including the process of bonding an optical member through an adhesive layer. It is preferable that the surface which contact|connects the adhesive layer of an optical member performs surface activation processing, such as a corona treatment, for the purpose of adjusting adhesive force. The conditions of a corona treatment can be set suitably, and conditions may differ from one surface of a bonding surface and another surface. Moreover, when a bonding surface is a transparent conductive layer of a touch sensor panel, it is preferable not to perform corona treatment.

<Display device>

A display device according to the present invention includes the optical laminate according to the present invention. A display apparatus is not specifically limited, For example, Image display apparatuses, such as an organic electroluminescent display apparatus, an inorganic electroluminescent display apparatus, a liquid crystal display device, and an electroluminescent display apparatus, are mentioned. The display device containing the optical laminated body of this invention has the outstanding impact resistance, and can also be used as a flexible display in which bending|flexion, winding, etc. are possible.

A display device WHEREIN: The optical laminated body is arrange|positioned on the visual recognition side of the display element which a display apparatus has toward the outer side (a side opposite to the display element side, ie, the visual recognition side) of a 1st optical member (front plate). It is preferable that the display device is bendable with the first optical member (front plate) side inside. The display device may be bendable with the first optical member (front plate) side outward.

The display device according to the present invention is preferable as a display device of a touch panel type, and is particularly preferable as a display device capable of inputting with a stylus pen.

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 signage, a measuring instrument or instrument, an office device, a medical device, a computer device, and the like.

(Example)

Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these.

[Measurement of thickness]

The thickness of each layer constituting the optical laminate was measured using a contact-type film thickness measuring device ("MS-5C" manufactured by Nikon Corporation).

[Measurement of yield stress of optical member]

The yield stress of the optical member used by the optical laminated body was measured in the following procedure. From the optical member to be measured, a rectangular piece of 110 mm long x 10 mm short was cut out using a super cutter. Next, with the upper and lower chucks of a tensile testing machine [Autograph AG-Xplus testing machine manufactured by Shimadzu Corporation], the long-side both ends of the sample for measurement are sandwiched so that the chuck interval is 5 cm, temperature 23°C, relative humidity 55% Under the environment of , the sample for measurement was pulled in the longitudinal direction of the sample for measurement at a tensile rate of 4 mm/min, a stress-strain curve was created, and the yield stress [MPa] at the yield point was calculated. At this time, as thickness for calculating stress, the thickness value of the optical member measured as mentioned above was used. In the obtained stress-strain curve, when the yield point was not confirmed, the stress at the time of not returning to the original length when the load was removed and residual strain of 0.2% was made into the yield stress.

[Measurement of storage modulus of adhesive layer]

For the measurement sample in which the pressure-sensitive adhesive layer was stacked to a thickness of 150 µm, using a rheometer (Anton Parr, MCR-301), stored under the conditions of a temperature of 25° C., a relative humidity of 50%, a stress of 1%, and a frequency of 1 Hz. The elastic modulus was measured.

[Preparation of the adhesive layer]

(Adhesive layer 1a)

The adhesive composition which forms the adhesive layer a by the ratio of each component shown in following Table 1 was prepared. This adhesive composition was apply|coated on the release-treated surface of the polyethylene terephthalate film (38 micrometers in thickness) by which the release process was carried out so that the thickness after drying might be set to 15 micrometers using the applicator. The application layer was dried at 100 degreeC for 1 minute, and the film provided with the adhesive layer a was obtained. Then, on the adhesive layer a, the other polyethylene terephthalate film (38 micrometers in thickness) by which the mold release process was carried out was pasted together. Thereafter, it was cured for 7 days under conditions of a temperature of 23°C and a relative humidity of 50%RH. About the adhesive layer 1a, when the storage elastic modulus was measured as mentioned above, it was 0.05 Mpa.

The symbol in the column of the monomer in Table 1 shows the following meaning.

BA: butyl acrylate

2EHA: 2-ethylhexyl acrylate

4HBA: 4-hydroxybutyl acrylate

The following crosslinking agents and silane coupling agents in Table 1 were used.

Crosslinking agent: Colonate L (manufactured by TOSOH CORPORATION)

Silane coupling agent: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

(Adhesive layer 1b, 1c, 2a, 2b, 2c, 2d, 2e, 3a, 3b, 3c)

In the ratio of each component shown in Table 1 below, except that the thickness after drying was set to Table 1 below, in the same manner as in the pressure-sensitive adhesive layer 1a, the pressure-sensitive adhesive layers 1b, 1c, 2a, 2b, 2c, 2d, 2e, 3a , 3b, 3c were obtained. About each adhesive layer, the storage elastic modulus measured as mentioned above was measured. Table 1 shows the measurement results.

[Table 1]

[Production of first optical member (front plate)]

(Preparation Example 1A)

In a nitrogen atmosphere, in a 1 L separable flask equipped with a stirring blade, 52 g (162.38 mmol) of 2,2'-bis (trifluoromethyl) benzidine (TFMB) and N,N-dimethylacetamide adjusted to 500 ppm (DMAc) 693.8 g was added, and TFMB was dissolved in DMAc while stirring at room temperature. Next, in a flask, 28.90 g (65.05 mmol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) ) 9.57 g (32.52 mmol) was added, and the mixture was stirred at room temperature for 3 hours. Then, 13.21 g (63.10 mmol) of terephthaloyl chloride (TPC) was added to the flask, and it stirred at room temperature for 1 hour. Then, 4.99 g (63.10 mmol) of pyridine and 21.91 g (214.66 mmol) of acetic anhydride were added to the flask, stirred at room temperature for 30 minutes, the temperature was raised to 70° C. using an oil bath, and the mixture was further stirred for 3 hours, A reaction solution was obtained. The obtained reaction liquid was cooled to room temperature, and it injected|threw-in in a large amount of methanol by filament, and the precipitated deposit was taken out, immersed in methanol for 6 hours, and it wash|cleaned with methanol. Next, the precipitate was dried under reduced pressure at 100°C to obtain polyamideimide resin.

DMAc was added to the obtained polyamideimide resin so that the density|concentration might be 15 mass %, and the polyamideimide varnish was produced. The obtained polyamideimide varnish was coated on the smooth surface of a polyester base material (manufactured by TOYOBO CO., LTD., trade name "A4100") using an applicator so that the film thickness of the self-supporting film was 30 μm, and then at 50° C. for 30 minutes. Then, it dried at 140 degreeC for 15 minutes, and obtained the self-supporting film. The free-standing film was fixed to a gold frame, and further dried at 300°C for 30 minutes in the atmosphere to obtain a polyamideimide film having a thickness of 25 µm.

(Preparation Example 1B)

Except having changed the coating thickness, it carried out similarly to manufacture example 1, and obtained the polyamideimide film with a film thickness of 45 micrometers.

(Preparation Example 1C)

Except having changed the coating thickness, it carried out similarly to manufacture example 1, and obtained the polyamideimide film with a film thickness of 75 micrometers.

(Hard Coating Layer Composition)

The composition for the hard coating layer is a multifunctional acrylate (MIWON Specialty Chemical Co., Ltd (Korea), MIRAMER M340) 30 parts by weight, nano silica sol dispersed in propylene glycol monomethyl ether (average particle size 12 nm, solid content 40%) 50 Parts by weight, 17 parts by weight of ethyl acetate, 2.7 parts by weight of a photopolymerization initiator (Ciba, I184), and 0.3 parts by weight of a fluorine-based additive (Shin-Etsu Chemical Co., Ltd., KY1203) were blended using a stirrer, and polypropylene (PP) ), a composition for a hard coat layer was prepared by filtration using a filter made of a material.

(1st optical member 1A)

The hard-coat layer composition was apply|coated to the polyamideimide film obtained by manufacture example 1A so that the film thickness might be set to 5 micrometers. The film was dried to obtain a polyamideimide film with a 30 µm thick hard coat layer.

(1st optical member 1B)

The hard-coat layer composition was apply|coated to the polyamideimide film obtained by manufacture example 1B so that the film thickness might be set to 5 micrometers. The film was dried to obtain a polyamideimide film with a 50 µm-thick hard coat layer.

(1st optical member 1C)

The hard-coat layer composition was apply|coated to the polyamideimide film obtained in manufacture example 1C so that the film thickness might be set to 5 micrometers. The film was dried to obtain a polyamideimide film with a thickness of 80 µm hard coat layer.

[Production of the second optical member (guard plate)]

(2nd optical member 2A)

Referring to Reference Examples and Examples of WO2014/030474, a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 60 µm was obtained.

(2nd optical member 2B)

Referring to Reference Examples and Examples of WO2014/030474, a biaxially oriented PET film having a thickness of 50 µm was obtained.

(2nd optical member 2C)

Referring to Reference Examples and Examples of WO2014/030474, a biaxially oriented PET film having a thickness of 80 μm was obtained.

(2nd optical member 2D)

Referring to Reference Examples and Examples of WO2014/030474, a biaxially stretched PET film having a thickness of 40 µm was obtained.

[Production of the third optical member (circularly polarizing plate)]

<Preparation of the composition for forming a polarizer layer>

(Polymerizable liquid crystal compound)

The polymerizable liquid crystal compound is a polymerizable liquid crystal compound represented by formula (1-6) [hereinafter also referred to as compound (1-6)] and a polymerizable liquid crystal compound represented by formula (1-7) [hereinafter referred to as compound ( 1-7)] was used.

Compound (1-6) and compound (1-7) are described in Lub et al. Recl. Trav. Chim. It was synthesized according to the method described in Pays-Bas, 115, 321-328 (1996).

(dichroic pigment)

The azo dye described in the Example of Unexamined-Japanese-Patent No. 2013-101328 shown by following formula (2-1a), (2-1b), (2-3a) was used for a dichroic dye.

(Preparation of the composition for polarizer layer formation)

The composition for polarizer layer formation is compound (1-6) 75 mass parts, compound (1-7) 25 mass parts, said Formula (2-1a) as said dichroic dye, (2-1b), (2-3a) 2.5 parts by mass each of the azo dye represented by , 6 parts by mass of 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369, manufactured by BASF Japan Ltd.) as a polymerization initiator; And 1.2 mass parts of polyacrylate compounds (BYK-361N, BYK-Chemie company make) as a leveling agent were mixed with 400 mass parts of toluene of a solvent, and it prepared by stirring the obtained mixture at 80 degreeC for 1 hour.

<λ/4 floor>

A composition for forming a horizontal alignment film was obtained by mixing 5 parts of a photo-alignment material having the following structure (weight average molecular weight: 30,000) and 95 parts of cyclopentanone, and stirring the resulting mixture at 80°C for 1 hour.

With respect to 100 parts of a mixture obtained by mixing the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B shown below in a mass ratio of 90:10, 1.0 part of a leveling agent (F-556; manufactured by DIC Corporation) and 2 which is a polymerization initiator -Dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Ltd.) was added in 6 parts.

Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that solid content concentration might be 13 %, and the composition (1) for retardation layer formation was obtained by stirring at 80 degreeC for 1 hour.

The polymerizable liquid crystal compound A was manufactured by the method described in Unexamined-Japanese-Patent No. 2010-31223. In addition, the polymerizable liquid crystal compound B was manufactured according to the method of Unexamined-Japanese-Patent No. 2009-173893. Each molecular structure is shown below.

(Polymerizable liquid crystal compound A)

(Polymerizable Liquid Crystal Compound B)

A base film made of a cycloolefin polymer (COP) film (Zeon Corporation, ZF-14, thickness 23 μm) was subjected to a corona treatment device (AGF-B10, manufactured by KASUGA DENKI, INC.) with an output of 0.3 kW and a processing speed It corona-treated once under the conditions of 3 m/min. The composition for forming a horizontal alignment film was apply|coated to the surface of the base material which corona-treated with the bar coater. The coating film was dried at 80 degreeC for 1 minute, and polarization|polarized-light UV exposure was performed using the polarization|polarized-light UV irradiation apparatus (SPOT CURE SP-7; Ushio Inc. product) with the accumulated light quantity of 100 mJ/cm<2>. It was 100 nm when the thickness of the obtained horizontal alignment film was measured with the laser microscope (LEXT, product made by Olympus Corporation).

Next, the composition for forming a retardation layer (1) was passed through a membrane filter made of PTFE (manufactured by ADVANTEC, part number; T300A025A) having a pore diameter of 0.2 μm under an environment of room temperature 25° C. and humidity 30% RH, and kept at 25° C. It apply|coated using the bar coater on the base film with an orientation film. After drying the coating film at 120°C for 1 minute, using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Inc.), ultraviolet rays are irradiated (under nitrogen atmosphere, wavelength: 365 nm, accumulated light quantity at wavelength 365 nm) : 1000 mJ/cm 2 ) to create an optical film. It was 2 micrometers when the thickness of the obtained coating film was measured with the laser microscope (LEXT, product made from Olympus Corporation).

In this way, the layer (λ/4 layer) in which the polymerizable liquid crystal compound was cured, the horizontal alignment film, and the base film were laminated in this order to obtain a laminate (retardation layer 1). The retardation layer 1 exhibited reverse wavelength dispersion.

<Positive C layer>

As a composition for forming a vertical alignment layer, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis(2-vinyloxyethyl) ether were mixed in 1:1:4:5. was mixed in a ratio of , and a mixture in which LUCIRIN TPO was added in a ratio of 4% as a polymerization initiator was used.

The composition for retardation layer formation (2) was prepared by preparing a photopolymerizable nematic liquid crystal compound (manufactured by Merck, RMM28B) and a solvent so that solid content might be 1-1.5 g. The solvent is a mixed solvent in which methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) are mixed in a mass ratio (MEK:MIBK:CHN) in a ratio of 35:30:35. used

A polyethylene terephthalate (PET) film having a thickness of 38 µm was prepared as a base film. The composition for vertical alignment film formation was apply|coated to the single side|surface of a base film so that it might become a film thickness of 3 micrometers, 200 mJ/cm<2> ultraviolet-ray was irradiated, and the vertical alignment film was produced.

On the vertical alignment film, the composition (2) for phase difference layer formation was coated by die-coating. The coating amount was 4 to 5 g (wet). The coating film was dried by making the drying temperature into 75 degreeC and drying time into 120 second. Thereafter, the coating film was irradiated with ultraviolet (UV) light to polymerize the polymerizable liquid crystal compound. It was 1 micrometer when the thickness of the obtained coating film was measured with the laser microscope (LEXT, the product made by Olympus Corporation).

In this way, the layer (positive C layer) in which the polymerizable liquid crystal compound was hardened, the vertical alignment film, and the base film were laminated in this order to obtain a laminate (retardation layer 2). In the retardation layer 2, the total thickness of the layer in which the polymerizable liquid crystal compound was cured and the alignment film was 4 µm.

<phase difference layer>

The retardation layer 1 and the retardation layer 2 mentioned above are bonded together through an ultraviolet curing adhesive layer (thickness 1.5 micrometers) so that the surface on the side opposite to the surface by the side of a base film may become a bonding surface, and base film/horizontal orientation film/(λ/) The retardation layer which has a structure of 4 layers)/ultraviolet hardening-type adhesive bond layer (1.5 micrometers in thickness)/positive C layer/vertical orientation film/base film was obtained.

<Linear Polarizer>

On a triacetyl cellulose (TAC) film (thickness 25 µm), the composition for forming an alignment film was applied by a bar coating method. The coating film was dried at 80 degreeC for 1 minute. Then, polarized UV was irradiated to the coating film using the UV irradiation apparatus and the wire grid, and alignment performance was imparted to the coating film. The exposure dose was 100 mJ/cm 2 (based on 365 nm). As the wire grid, UIS-27132## (manufactured by Ushio Inc.) was used. In this way, an alignment film was formed. The thickness of the alignment film was 100 nm.

On the formed alignment film, the composition for forming a polarizer layer was applied by a bar coating method. After heating and drying the coating film at 100 degreeC for 2 minutes, it cooled to room temperature. The polarizer layer was formed by irradiating an ultraviolet-ray to the coating film with the accumulated light amount of 1200 mJ/cm<2> (365 nm reference|standard) using the said UV irradiation apparatus. The thickness of the obtained polarizer layer was 3 micrometers. On the polarizer layer, the composition containing polyvinyl alcohol and water was coated so that the thickness after drying might be set to 0.5 micrometer, and it dried at the temperature of 80 degreeC for 3 minutes, and the protective layer was formed. In this way, the linear polarizing plate which has the structure of TAC film/alignment film/polarizer layer/protective layer was produced.

<Circular Polarizer>

The base film used for formation of (lambda)/4 layer was peeled from the retardation layer mentioned above. The exposed λ/4 layer and the linear polarizing plate were bonded together with an ultraviolet curing adhesive (Adeka Acools KR series, manufactured by ADEKA), and “TAC film/orientation film/polarizer layer/protective layer/ultraviolet curing adhesive layer (thickness 1.5 µm)/(λ/4 layer)/ultraviolet ray curing adhesive layer (thickness 1.5 µm)/positive C layer/vertical alignment film/base film” was obtained. The angle between the absorption axis of the polarizer layer and the slow axis of the λ/4 layer was 45°.

[Examples 1 to 4, Comparative Examples 1 and 2]

The optical laminates of Examples 1-4 and Comparative Examples 1 and 2 were produced in the following procedure. First, the base film used for formation of the positive C layer of the circularly polarizing plate (3rd optical member) prepared as mentioned above was peeled. Then, the film provided with the 3rd adhesive layer of Table 2 was prepared, one polyethylene terephthalate film was peeled, and the surface of the 3rd adhesive layer was exposed. After corona-treating the exposed surface of a 3rd optical member, and the surface of a 3rd adhesive layer, both were bonded together and the laminated body which consists of "3rd optical member/3rd adhesive layer" was obtained. Then, using the 1st optical member of Table 2, the 1st adhesive layer, the 2nd optical member, and the 2nd adhesive layer, these are laminated|stacked, and "1st optical member / 1st adhesive layer / 2nd optical member / The optical laminated body of the laminated constitution which consists of 2nd adhesive layer / 3rd optical member / 3rd adhesive layer was obtained. The 1st optical member was laminated|stacked so that the surface on the side opposite to the 1st adhesive layer side might be comprised with the hard-coat layer.

[Calculation of ratio]

About each optical laminated body, thickness T 1 [micrometer] of a 1st optical laminated body, thickness t ₁ [micrometer] of a 1st adhesive layer, thickness t ₂ [micrometer] of a _2nd adhesive layer, thickness of a 3rd adhesive layer From t ₃ [µm], T ₁ /t ₁ , T ₁ /t ₂ , and T ₁ /t ₃ were calculated. Table 2 shows the calculation results. In addition, about each optical laminated body, the value _of S2/ _G'2 is computed using yield stress S2 [MPa] of a _2nd optical laminated body, and storage elastic modulus G'2 [MPa] of a _2nd adhesive layer. did. Table 2 shows the calculation results.

[Measurement of pressing depth]

For the optical laminates of Examples 1 to 4 and Comparative Examples 1 and 2, the third pressure-sensitive adhesive layer was exposed, and as a substitute for the organic EL panel, "polyimide film (thickness 35 µm)/adhesive layer (thickness 25) μm) / polyimide film (thickness 50 μm)”, laminated so that the polyimide film (thickness 35 μm) side is in contact with the third pressure-sensitive adhesive layer, cut out to a size of 20 mm × 110 mm A laminate for testing was obtained.

For the test laminate, on the surface of the first optical member (front plate), the test pen (Samsung Galaxy Note 10 Digitiger S-pen, mass: 500 g, tip material: polyoxymethylene) was placed at a 90 degree angle. At an angle, it fixed so that it may contact with the pressure of 1.3 kg/mm<2>, and the pen for a test was made to reciprocate a 50 mm straight line at a speed|rate of 500 mm/min. And after leaving it to stand for 2 hours, the pressing depth was measured using the two-dimensional measuring machine (DEKTAK 6M; Veeco company make). Let the pressing depth be the maximum of the depth (depression from the periphery) on the straight line in which the pen for a test was made one reciprocating in the surface of the 1st optical member (front plate) of the laminated body for a test. Table 2 shows the measured values of the pressing depth.

[Table 2]

10: front plate (first optical member) 11: substrate
12: hard coating layer 22: 2nd optical member
23: third optical member 24: fourth optical member
31: first pressure-sensitive adhesive layer 32: second pressure-sensitive adhesive layer
33: third pressure-sensitive adhesive layer 100: optical laminate

Claims (8)

An optical laminate in which a first optical member as a front plate, a first pressure-sensitive adhesive layer, a second optical member, and a second pressure-sensitive adhesive layer are laminated in contact with each other in this order,
When the yield stress of the second optical member is S ₂ [MPa] and the storage elastic modulus of the second pressure-sensitive adhesive layer is G′ ₂ [MPa], the following formula (1):
46 ≤ S ₂ /G' ₂ ≤ 17500 (1)
An optical laminate that satisfies the relationship of The method of claim 1,
When the yield stress of the first optical member is S ₁ [MPa], the following formula (2):
70 MPa ≤ S ₁ ≤ 180 MPa (2)
An optical laminate that satisfies the relationship of 3. The method of claim 1 or 2,
When the thickness of the first optical member is T ₁ [μm] and the thickness of the first pressure-sensitive adhesive layer is t ₁ [μm], the following formula (3):
1.5 ≤ T ₁ /t ₁ ≤ 5 (3)
An optical laminate that satisfies the relationship of 3. The method of claim 1 or 2,
When the thickness of the first optical member is T ₁ [μm] and the thickness of the second pressure-sensitive adhesive layer is t ₂ [μm], the following formula (4):
1.5 ≤ T ₁ /t ₂ ≤ 5 (4)
An optical laminate that satisfies the relationship of 3. The method of claim 1 or 2,
As for the said 1st optical member, the surface on the opposite side to the said 1st adhesive layer side is comprised with the hard-coat layer, The optical laminated body. 3. The method of claim 1 or 2,
An optical laminate having a polarizing plate. 3. The method of claim 1 or 2,
An optical laminate having a touch sensor panel. A display device comprising the optical laminate according to claim 1 or 2.

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