KR20200098418A - Laminated body and image display device - Google Patents

Abstract

The present invention relates to laminates and an image displaying apparatus. An objective of the present invention is to provide the laminates which is less likely to be cracked even when repeatedly bent. The laminates of the present invention include at least one structure in which optical members are laminated to each other through an adhesive layer. Here, a rate of change (%/ten thousand times) of a thickness per unit bending number of at least one adhesive layer in a structure is less than 10.

Description

Laminated body and image display device {LAMINATED BODY AND IMAGE DISPLAY DEVICE}

The present invention relates to a laminate, and further to an image display device including the laminate.

Patent Document 1 proposes a polarizing film having a pressure-sensitive adhesive layer on both sides of a polarizing film, and a polarizing film having a double-sided pressure-sensitive adhesive layer, wherein the thickness of the pressure-sensitive adhesive layer is 25 μm or more and 25 μm or less, respectively.

In Patent Document 2, a pressure-sensitive adhesive optical film having a pressure-sensitive adhesive layer, wherein the standard deviation value of the thickness of the pressure-sensitive adhesive layer is 0.12 μm or less, is proposed.

Korean Patent No. 10-2017-7033089 Specification Korean Patent No. 10-2013-7001791 Specification

In a laminate having a structure in which optical members are laminated to each other through an adhesive layer, cracks may occur when the laminate is repeatedly bent.

An object of the present invention is to provide a laminate that is less likely to crack even when repeatedly bent.

The present invention provides the following laminate and an image display device.

[1] A laminate comprising at least one structure in which an optical member is laminated to each other through a pressure-sensitive adhesive layer, and at least one of the structures wherein the pressure-sensitive adhesive layer satisfies the following formula (i).

Rate of change in thickness per unit bending number [%/10,000 times] <10 (i)

[2] The laminate according to [1], wherein the thickness of the pressure-sensitive adhesive layer satisfying the formula (i) is 5 μm or more.

[3] The laminate according to [1] or [2], wherein all of the pressure-sensitive adhesive layers satisfy the formula (i).

[4] The structure in which the optical members are stacked on each other through an adhesive layer is a structure in which two optical members selected from the group consisting of a front plate, a polarizing plate, a touch sensor panel, and an organic EL display device are stacked through the adhesive layer. And the laminate according to any one of [1] to [3].

[5] An image display device comprising the laminate according to any one of [1] to [4].

[6] The image display device according to [5], having flexibility.

According to the present invention, it is possible to provide a laminate in which cracks are less likely to occur even when repeatedly bent.

1 is a schematic cross-sectional view showing an example of a laminate according to the present invention.
2 is a schematic cross-sectional view showing an example of a laminate according to the present invention.
3 is a schematic cross-sectional view showing an example of a laminate according to the present invention.
4 is a cross-sectional view schematically showing an example of a method for manufacturing an optical laminate of the present invention.
5 is a schematic diagram illustrating a flexural test method.

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 scales are appropriately adjusted to make each component easier to understand, and the scale of each component shown in the drawings and the actual scale of the component do not necessarily match.

<Laminate>

1 is a schematic cross-sectional view of a laminate (hereinafter, also referred to as "laminate" for abbreviation) according to an embodiment of the present invention. The laminated body 1 shown in FIG. 1 is provided with the optical member 2, the adhesive layer 3, and the optical member 2 in this order. The laminate 1 is a laminate comprising one structure in which optical members are laminated to each other through an adhesive layer, and is a laminate made of only a structure in which the optical members are laminated to each other through an adhesive layer.

The laminate has flexibility. To have flexibility means that when the laminate is bent, it can be bent without causing cracks and fractures. Having flexibility means that cracks and fractures do not occur even when bending is performed 30,000 times, preferably with a bending radius of 2.5 mm on the inner surface of the laminate.

The thickness of the laminate 1 is not particularly limited because it differs depending on the function required for the laminate 1 and the use of the laminate 1, but for example, it may be 50 μm or more and 1000 μm or less, and preferably 100 μm or more. It is 500 μm or less, and more preferably 100 μm or more and 300 μm or less.

The planar shape of the laminate 1 may be, for example, a square shape, preferably a square shape having a long side and a short side, and more preferably a rectangular shape. When the planar shape of the layered product 1 is rectangular, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, and preferably 50 mm or more and 600 mm or less. The length of the short side is, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less.

When the planar shape of the laminate 1 is a square shape, the lengths of each side in each layer constituting the laminate 1 may be the same. Each layer constituting the layered product 1 may be subjected to R-processing, notched end portions, or hole-opening processing.

In this specification, planar view means viewing from the thickness direction of a layer.

As described above, when the laminate 1 is repeatedly bent so that the inner surface of the laminate 1 has a bending radius of 2.5 mm with respect to at least one direction within its surface, the number of bendings is preferably 3 Even if it is recovered, neither crack nor break occurs.

When the laminate 1 is repeatedly bent so that the inner surface of the laminate 1 has a bending radius of 2.5 mm in at least one direction within its surface, more preferably, even if the number of bends is 50,000, cracks and No fracture occurs, more preferably, even if the number of bends is 100,000 times, no cracks and fractures do not occur, and even more preferably, even if the number of bends is 300,000 times, no cracks and fractures occur. In the laminated body 1, it is preferable that the number of bending times in which cracks and fractures do not occur at least in one direction within the plane and a direction orthogonal thereto is within the above range when the repeated bending is performed.

In the present specification, the bend includes a bent shape in which a curved surface is formed in the bent portion. In the bending form, the bending radius of the bent inner surface is not particularly limited. In addition, the bend includes a form of refraction in which the angle of refraction of the inner surface is greater than 0 degrees and less than 180 degrees, and a form in which the radius of refraction of the inner surface is approximated to zero, or that the angle of refraction of the inner surface is 0 degrees.

The structure in which the optical members are laminated to each other through an adhesive layer may be a structure composed of a single structure 1, for example, when the optical member/adhesive layer/optical member is a unit structure (hereinafter referred to as structure 1). , A structure composed of a plurality of structures 1 may be used. In the case of a structure composed of a plurality of structures 1, two or more structures 1 may be stacked through an adhesive layer, and an optical member is further bonded to one optical member constituting the structure 1 through an adhesive layer. It may be. Each optical member may be of the same type or may be of different types, but is preferably of a different type. In addition, each of the pressure-sensitive adhesive layers may have the same composition or different compositions, but preferably the same composition.

Here, as a structure in which the optical members are laminated to each other through an adhesive layer, a structure in a polarizing plate and a structure between a retardation film to be described later may be included. For example, a structure in which a polarizer and a retardation film or a retardation layer included in a polarizing plate are stacked through an adhesive layer, a structure in which a retardation film and a retardation layer are laminated through an adhesive layer, or a structure in which a retardation film or a retardation layer is laminated with each other A structure stacked through layers may be included. More specifically, a structure in which a polarizer and a λ/4 plate included in a polarizing plate are stacked through an adhesive layer, a structure in which a λ and/4 plate and a positive (C) plate or a λ/2 plate are stacked through an adhesive layer, etc. are mentioned. have.

When the laminate contains two or more structures 1, these structures may be bonded through an adhesive layer or a bonding layer described later.

At least one of the structures in which optical members are stacked with each other through an adhesive layer, the adhesive layer satisfies the following formula (i).

Rate of change in thickness per unit bending number [%/10,000 times] <10 (i)

The change rate [%/ten thousand times] of the thickness per unit bending number of at least one of the structures in which the optical members are stacked with each other through an adhesive layer is preferably 5 or less, more preferably 4 or less, and further Preferably it is 2 or less. From the viewpoint of increasing the flexibility, preferably, in the structure in which the optical members are stacked with each other through an adhesive layer, all of the adhesive layers satisfy the formula (i).

The rate of change in thickness per unit number of bends [%/10,000 times] refers to the thickness of the initial pressure-sensitive adhesive layer, that is, when the number of bends is 0, when the laminate is repeatedly bent 10,000 times so that the inner bend radius is 2.5mm. When the thickness of the pressure-sensitive adhesive layer is T ₀ , and the thickness of the pressure-sensitive adhesive layer when repeatedly bent 10,000 times is T ₁ , it can be calculated according to the following equation.

Rate of change in thickness per unit bending number [%/ _ten thousand times]=｜T ₁ -T ₀ ｜／T ₀ ×100

The thickness of the pressure-sensitive adhesive layer and the rate of change [%/ten thousand times] of the thickness per unit bending number of the pressure-sensitive adhesive layer can be obtained according to the method described in the Examples column to be described later.

When the laminate was repeatedly bent by the inventors, it was found that the thickness of the pressure-sensitive adhesive layer included in the structure in which the optical members are laminated with each other through the pressure-sensitive adhesive layer generally tends to increase in thickness. The present inventor conducted a study on the relationship between the rate of change of the thickness of the pressure-sensitive adhesive layer and the flexibility, and it was found that a small rate of change of thickness per unit number of bends tends to have good flexibility of the laminate. This is presumed to be because when the thickness of the pressure-sensitive adhesive layer increases, the stress generated inside the laminate increases when the laminate is bent, and cracks and fractures tend to occur.

In order to make the rate of change [%/ten thousand times] of the thickness per unit bending number less than 10, for example, it is possible to adjust the manufacturing conditions of the pressure-sensitive adhesive layer or select the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer. As for the adjustment of the manufacturing conditions of the pressure-sensitive adhesive layer, for example, when the pressure-sensitive adhesive layer is formed of an active energy ray-curable pressure-sensitive adhesive composition, increasing the curing degree of the active energy-ray-curable pressure-sensitive adhesive composition by increasing the irradiation amount of active energy rays increases the thickness per unit bending number. The rate of change [%/ten thousand times] tends to become small. In addition, when the amount of the crosslinking agent in the pressure-sensitive adhesive composition is increased, the rate of change [%/ten thousand times] of the thickness per unit bending number tends to become small.

Further, as the pressure-sensitive adhesive, when a pressure-sensitive adhesive having a large storage modulus [MPa] described later or a pressure-sensitive adhesive having a large recovery described later is used, the rate of change in thickness per unit bending number [%/10,000 times] tends to be small. The thickness of the pressure-sensitive adhesive layer that satisfies the above formula (i) may be, for example, 5 μm or more.

The pressure-sensitive adhesive layer may have a storage elastic modulus [MPa] at a temperature of 25°C and a relative humidity of 55%, for example, exceeding 0.02 MPa, preferably 0.03 MPa or more, and more preferably 0.05 MPa or more. On the other hand, the pressure-sensitive adhesive layer preferably has a storage modulus [MPa] of 0.1 MPa or less, and more preferably 0.08 MPa or less. When the storage elastic modulus [MPa] of the laminate is in the above range, there is a tendency that the change in the thickness of the pressure-sensitive adhesive layer is small even when repeatedly bent. The storage modulus [MPa] of the laminate can be measured according to the method described in the column of Examples to be described later.

The pressure-sensitive adhesive layer may have a recovery [%] at a temperature of 25° C. and a relative humidity of 55%, for example, 25% or more, and preferably 30% or more. On the other hand, the pressure-sensitive adhesive layer usually has a recovery [%] of, for example, 70% or less, and preferably 60% or less. When the recovery [%] of the laminate is within the above range, the change in the thickness of the pressure-sensitive adhesive layer tends to be small even when repeatedly bent. The recovery [%] of the laminate can be measured according to the method described in the column of Examples to be described later.

2 is a schematic cross-sectional view showing another example of the laminate according to the present invention. The laminate 4 shown in FIG. 2 is an optical member 5, an adhesive layer 6, an optical member 5, an adhesive layer 6, an optical member 5, an adhesive layer 6, and an optical member 5 ) In this order. The laminate 4 is a laminate including Structure 1 described above, and is a laminate made of only a structure in which optical members are laminated to each other through an adhesive layer.

3 is a schematic cross-sectional view showing still another example of the laminate according to the present invention. The laminate 7 shown in FIG. 3 is an optical member 8, an adhesive layer 9, an optical member 8, a bonding layer 10, an optical member 8, an adhesive layer 9, and an optical member 8 ) In this order. The laminate 7 is a laminate comprising two structures in which optical members are laminated to each other through a pressure-sensitive adhesive layer, and a structure in which optical members are laminated to each other through a pressure-sensitive adhesive layer is bonded to each other by a bonding layer 10 .

[Optical member]

Examples of the optical member include a front plate, a polarizing plate, a retardation film, a touch sensor panel, and an organic EL display device.

As a specific example of Structure 1 mentioned above, the following structures are mentioned, for example.

Front plate/adhesive layer/polarizing plate,

Polarizing plate/adhesive layer/touch sensor panel,

Touch sensor panel/adhesive layer/organic EL display device.

When the structure in which the optical members are laminated with each other through the pressure-sensitive adhesive layer has a plurality of Structure 1, the following structures may be mentioned as a specific example thereof.

Front plate/adhesive layer/polarizing plate/adhesive layer/touch sensor panel,

Front plate/adhesive layer/touch sensor panel/adhesive layer/polarizing plate,

Polarizing plate/adhesive layer/touch sensor panel/adhesive layer/organic EL display device,

Front panel/adhesive layer/polarizing plate/adhesive layer/touch sensor panel/adhesive layer/organic EL display device,

Front panel/adhesive layer/touch sensor panel/adhesive layer/polarizer/adhesive layer/organic EL display device.

[Front panel]

The front plate is preferably a plate-like body capable of transmitting light. The front plate may be composed of only one layer, or may be composed of two or more layers. The front plate may constitute the outermost surface of the image display device.

As the front plate, for example, a glass plate (for example, a glass plate, a glass film, etc.), a resin plate (for example, a resin plate, a resin sheet, a resin film, etc.) have. Among the above, from the viewpoint of the flexibility of the laminate and the image display device including the same, a plate-like member made of resin such as a resin film is preferable.

As a thermoplastic resin constituting a resin plate-like body such as a resin film, for example, a chain polyolefin resin (polyethylene resin, polypropylene resin, polymethylpentene resin, etc.), a cyclic polyolefin resin (Novo Polyolefin resins such as ene resins); Cellulose resins such as triacetyl cellulose; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; Polycarbonate resin; Ethylene-vinyl acetate resin; Polystyrene resin; Polyamide resin; Polyetherimide resin; (Meth)acrylic resins such as polymethyl (meth)acrylate resins; Polyimide resin; Polyethersulfone resin; Polysulfone resin; Polyvinyl chloride resin; Polyvinylidene resin; Polyvinyl alcohol resin; Polyvinyl acetal resin; Polyether ketone resin; Polyether ether ketone resin; Polyethersulfone resin; And polyamide-imide-based resins.

Thermoplastic resins may be used alone or in combination of two or more.

Among them, from the viewpoints of flexibility, strength and transparency, polyimide resins, polyamide resins, and polyamideimide resins are suitably used as the thermoplastic resin constituting the front plate.

The front plate may be a film in which hardness is further improved by providing a hard coat layer on at least one surface of the base film. As the base film, the resin film described above 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 a hard coat layer, hardness and scratch property can be improved. The thickness of the hard coat layer may be, for example, 0.1 μm or more and 30 μm or less, preferably 1 μm or more and 20 μm or less, and more preferably 5 μm or more and 15 μm or less.

The hard coat layer is, for example, a cured layer of an 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 an additive in order to improve the strength. The additive is not limited, and inorganic fine particles, organic fine particles, or mixtures thereof are exemplified.

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

The thickness of the front plate may be, for example, 20 μm or more and 2000 μm or less, preferably 25 μm or more and 1500 μm or less, more preferably 30 μm or more and 1000 μm or less, even more preferably 40 μm or more and 500 μm or less, particularly preferably 40 μm or more. It may be 200 μm or less, and even more preferably 40 μm or more and 100 μm or less.

[Polarizing plate]

Examples of the polarizing plate include a stretched film or a stretched layer in which a dichroic dye is adsorbed, or a film comprising a film formed by coating and curing a polymerizable compound containing a dichroic dye as a polarizer. When the dye is dispersed and oriented in an anisotropic medium, it will appear colored in any direction. It may appear almost colorless in the vertical direction. A pigment exhibiting this phenomenon is called a dichroic pigment. As the dichroic dye, specifically, iodine or a dichroic organic dye is used. Dichroic organic dyes include dichroic direct dyes composed of disazo compounds such as C.I.DIRECT RED 39, dichroic direct dyes composed of compounds such as tris azo and tetrakis azo.

As a film formed by coating and curing a polymerizable compound containing a dichroic dye, a layer obtained by curing a composition comprising a dichroic dye having liquid crystal properties or a composition comprising a dichroic dye and a polymerizable liquid crystal is applied and cured A film containing a cured product of such as a polymerizable liquid crystal compound is mentioned.

A film formed by coating and curing a polymerizable compound containing a dichroic dye is preferable because there is no limitation in the direction of bending compared to a stretched film or a stretched layer in which a dichroic dye is adsorbed. Therefore, at least one direction in the plane and a direction orthogonal thereto, and furthermore, in all directions in the plane, a laminate having the number of bends in the above range without cracks when repeated bending is obtained, and a polarizing plate As an example, a film comprising a film obtained by curing by applying a polymerizable compound containing a dichroic dye as a polarizer is preferable.

(1) Polarizing plate provided with a polarizer which is a stretched film or a stretched layer

Polarizer, which is a stretched film adsorbed with a dichroic dye, is usually a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of adsorbing the dichroic dye by dyeing a polyvinyl alcohol-based resin film with a dichroic dye, and dichroic A polyvinyl alcohol-based resin film with adsorbed properties can be prepared through a step of treating with an aqueous boric acid solution, and then washing with water after treatment with an aqueous boric acid solution. Such a polarizer may be used as it is as a polarizing plate, or a material obtained by bonding a transparent protective film on one or both sides thereof may be used as a polarizing plate. The thickness of the polarizer is preferably 2 μm or more and 40 μm or less.

Polyvinyl alcohol-based resin can be obtained by saponification of polyvinyl acetate-based resin. As the polyvinyl acetate resin, a copolymer of vinyl acetate and another monomer copolymerizable therewith other than polyvinyl acetate, which is a homopolymer of vinyl acetate, is used. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carbon acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

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

The polarizer, which is a stretched layer adsorbed with a dichroic dye, is usually a step of applying a coating liquid containing the polyvinyl alcohol-based resin onto a base film, a step of uniaxially stretching the obtained laminated film, and a polyvinyl of the uniaxially stretched laminated film. By dyeing the alcohol-based resin layer with a dichroic dye, the process of adsorbing the dichroic dye to form a polarizer, the process of treating the film adsorbed with the dichroic dye with an aqueous boric acid solution, and the process of washing with water after treatment with the aqueous boric acid solution Can be manufactured through

If necessary, the base film may be peeled off from the polarizer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described later.

The polarizer, which is a stretched film or a stretched layer, may be incorporated into the optical laminate in a form in which a thermoplastic resin film is adhered to one or both sides thereof. This thermoplastic resin film can function as a protective film for polarizers or a retardation film.

The thermoplastic resin film includes, for example, polyolefin resins such as chain polyolefin resins (polypropylene resins, etc.) and cyclic polyolefin resins (norbornene resins, etc.); Cellulose resins such as triacetyl cellulose; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; Polycarbonate resin; (Meth)acrylic resin; Or it may be a film made of these mixtures or the like.

The thickness of the thermoplastic resin film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, most preferably 60 μm or less, from the viewpoint of thinning. It is 5 μm or more, preferably 20 μm or more.

The thermoplastic resin film may or may not have a retardation.

The thermoplastic resin film can be bonded to the polarizer using, for example, an adhesive layer.

(2) A polarizing plate provided with a film formed by coating and curing a polymerizable compound containing a dichroic dye as a polarizer

As a film formed by coating and curing a polymerizable compound containing a dichroic dye, a composition containing a polymerizable dichroic dye having liquid crystal properties or a composition containing a dichroic dye and a polymerizable liquid crystal is used as a base film (or substrate). A film including a cured product of a polymerizable liquid crystal compound such as a layer obtained by coating and curing the alignment film formed on the film), and the like may be mentioned.

The film may be used as a polarizing plate by peeling the substrate or together with the substrate. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described above.

A film formed by coating and curing a polymerizable compound containing a dichroic dye may be incorporated into a laminate in a form in which a thermoplastic resin film is adhered to one or both sides thereof. As the thermoplastic resin film, the same thermoplastic resin film that can be used for a stretched film or a polarizer serving as a stretched layer can be used.

The thermoplastic resin film can be bonded to the polarizer using, for example, an adhesive layer. As a film formed by coating and curing a polymerizable compound containing a dichroic dye, specifically, those described in Japanese Unexamined Patent Application Publication No. 2012-33249 or the like can be mentioned.

The thickness of the film formed by coating and curing the polymerizable compound containing a dichroic dye is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 5 μm or less.

The thickness of the polarizing plate is, for example, 2 μm or more and 100 μm or less, and preferably 10 μm or more and 60 μm or less.

The polarizing plate may further include a retardation film. The retardation film may include one or two or more retardation layers. The phase difference layer may be a positive (A) plate such as a λ/4 plate or a λ/2 plate, and a positive (C) plate. The retardation layer may be formed of a resin film exemplified as a material for the above-described protective film, or may be formed of a layer in which a polymerizable liquid crystal compound is cured. The retardation film may further include an alignment film or a base film.

When the polarizer and the retardation film are arranged so that the absorption axis of the polarizer and the slow axis of the retardation film become a predetermined angle, the laminate including the polarizing plate and the retardation film has an antireflection function, that is, the laminate is It can function as a circular polarizer. When the retardation film is a retardation film including a λ/4 plate as a retardation layer, an angle formed between the absorption axis of the polarizer and the slow axis of the λ/4 plate may be 45°±10°.

The polarizing plate and the retardation film can be bonded together via a bonding layer described later or an adhesive layer. The pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive composition described later, or may be a pressure-sensitive adhesive layer from another pressure-sensitive adhesive composition. The thickness of the pressure-sensitive adhesive layer may be, for example, 0.5 μm or more and 25 μm or less, and preferably 1 μm or more and 25 μm or less.

The thickness of the circular polarizing plate is, for example, 10 μm or more and 200 μm or less, and preferably 10 μm or more and 100 μm or less.

[Touch sensor panel]

If the touch sensor panel is a sensor capable of detecting the touched position, the detection method is not limited, and a touch sensor panel such as a resistive film method, a capacitive coupling method, an optical sensor method, an ultrasonic method, an electromagnetic induction coupling method, and a surface acoustic wave method is used. It is illustrated. In terms of low cost, resistive and capacitive-coupled touch sensor panels are very suitably used.

An example of a resistive touch sensor panel includes a pair of substrates disposed opposite to each other, an insulating spacer sandwiched between the pair of substrates, a transparent conductive film provided as a resistive film on the inner front surface of each substrate, and touch It is composed of a position detection circuit. In an image display device provided with a resistive touch sensor panel, when the surface of the front plate is touched, the opposing resistive film is short-circuited, and a current flows through the resistive film. The touch position detection circuit detects the change in voltage at this time, and the touched position is detected.

An example of a capacitive coupling type touch sensor panel includes a substrate, a transparent electrode for position detection provided on the front surface of the substrate, and a touch position detection circuit. In an image display device provided with a capacitive coupling type touch sensor panel, when the surface of the front plate is touched, the transparent electrode is grounded through the capacitance of the human body at the touched point. The touch position detection circuit detects the ground of the transparent electrode, and the touched position is detected.

The thickness of the touch sensor panel may be, for example, 5 μm or more and 2,000 μm or less, preferably 5 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

The touch sensor panel may have a touch sensor pattern formed on a base film. The example of the base film may be the same as the example in the description of the above-described protective film. The thickness of the touch sensor pattern may be, for example, 1 μm or more and 40 μm or less.

[Organic EL display device]

As the organic EL display device, a conventionally known one may be sufficient, and it is preferably an organic EL display device that can be used in a flexible image display device. The thickness of the organic EL display device may be, for example, 5 μm or more and 2,000 μm or less, preferably 5 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[Phase difference film]

The retardation film may include one or two or more retardation layers. The phase difference layer may be a positive (A) plate such as a λ/4 plate or a λ/2 plate, and a positive (C) plate. The retardation layer may be formed of a resin film exemplified as a material for the above-described protective film, or may be formed of a layer in which a polymerizable liquid crystal compound is cured. The retardation film may further include an alignment film or a base film.

The thickness of the retardation film formed of the resin film may be the same as that of the thermoplastic resin film described above. The thickness of the retardation layer formed by curing the polymerizable liquid crystal compound is, for example, 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 6 μm or less.

The retardation layer formed by curing the polymerizable liquid crystal compound can be formed by coating and curing the composition containing the polymerizable liquid crystal compound on a base film. An alignment layer may be formed between the base film and the coating layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described above.

Between the retardation films or between the retardation layers, or the retardation film and the retardation layer may be bonded through a bonding layer described later or an adhesive layer. The pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive composition described later, or may be a pressure-sensitive adhesive layer in other pressure-sensitive adhesive compositions. The thickness of the pressure-sensitive adhesive layer may be, for example, 0.5 μm or more and 25 μm or less, and preferably 1 μm or more and 25 μm or less.

[Adhesive layer]

The pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer included in a structure in which optical members are laminated to each other through an adhesive layer. The pressure-sensitive adhesive layer includes an adhesive layer in a structure in which a polarizing plate and a retardation film or a retardation layer are laminated through an adhesive layer, and a retardation film and a retardation layer, or between a retardation film, or a retardation layer are laminated to each other through an adhesive layer. May be.

The pressure-sensitive adhesive layer may be composed of one layer or two or more layers, but is preferably composed of one layer.

The pressure-sensitive adhesive layer may be composed of a pressure-sensitive adhesive composition containing as a main component a resin such as (meth)acrylic, rubber, urethane, ester, silicone, and polyvinyl ether. Among them, a pressure-sensitive adhesive composition comprising a (meth)acrylic resin excellent in transparency, weather resistance, heat resistance, and the like as a base polymer is very suitable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a heat curable type.

Examples of the (meth)acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, ( One or two (meth)acrylic acid esters such as lauryl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isobornyl (meth)acrylate Aggregates or copolymers using the above as a monomer are suitably used.

It is preferable to copolymerize a polar monomer to the base polymer. As a polar monomer, for example, (meth)acrylic acid, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylate hydroxyethyl, (meth)acrylamide, N, N-dimethylaminoethyl (meth)acrylate, Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as glycidyl (meth)acrylate, can be mentioned.

The weight average molecular weight (Mw) of the (meth)acrylic resin may be, for example, 700,000 or more and 2.5 million or less, and may be 1 million or more and 2 million or less. The molecular weight distribution represented by the ratio (Mw/Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) may be 10 or less, 8 or less, and 6 or less. The weight average molecular weight (Mw) can be determined by the following size exclusion chromatography (SEC). The weight average molecular weight (Mw) uses tetrahydrofuran for the mobile phase, the (meth)acrylic resin to be measured is dissolved in tetrahydrofuran at a concentration of about 0.05% by mass, and 10 μL is injected into SEC. The mobile phase flows at a flow rate of 1.0 mL/min. The weight average molecular weight (Mw) is a value calculated by conversion of polystyrene. PLgel MIXED-B (manufactured by Polymer Laboratories) can be used as a column. For the detector, a UV-VIS detector (trade name: Agilent GPC) can be used.

The pressure-sensitive adhesive composition may contain only the base polymer, but usually further contains a crosslinking agent. Examples of the crosslinking agent include divalent or higher metal ions, which form a carboxylate metal salt with a carboxyl group; A polyamine compound that forms an amide bond between a carboxyl group; A polyepoxy compound or a polyol, which forms an ester bond with a carboxyl group; As a polyisocyanate compound, what forms an amide bond with a carboxy group is illustrated. Among them, polyisocyanate compounds are preferable.

Examples of polyisocyanate compounds include aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate, etc.), alicyclic isocyanate compounds (e.g. isophorone diisocyanate), hydrogenated xylylene Diisocyanate, hydrogenated diphenylmethane diisocyanate, aromatic isocyanate compounds (e.g., tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc.), etc. I can. In addition, the polyisocyanate-based compound is an adduct (adduct form) of the polyhydric alcohol compound of the isocyanate compound [for example, an adduct form of glycerol, trimethylolpropane, etc.], an isocyanurate compound, and a biuret-type compound. , A polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, or the like may be a derivative such as a urethane prepolymer type isocyanate compound obtained by addition reaction. Polyisocyanate compounds may be used alone or in combination of two or more. Among these, from the viewpoint of durability, tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and polyhydric alcohol compounds thereof, or isocyanurate compounds thereof are preferable.

The proportion of the crosslinking agent may be, for example, 0.01 parts by mass or more and 10 parts by mass or less, preferably 0.1 parts by mass or more and 3 parts by mass or less, and more preferably 0.1 parts by mass or more and 1 part by mass or less, based on 100 parts by mass of the base polymer. .

The active energy ray-curable pressure-sensitive adhesive composition has a property of curing by being irradiated with active energy rays such as ultraviolet rays or electron beams, and has adhesiveness even before irradiation with active energy rays, so that it can be adhered to an adherend such as a film. It is a pressure-sensitive adhesive composition having a property that can be cured and adjusted such as adhesion.

It is preferable that an active energy ray-curable pressure-sensitive adhesive composition is 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 crosslinking agent. Further, if necessary, a photoinitiator or a photosensitizer may be contained.

Examples of the active energy ray polymerizable compound include (meth)acrylate monomers having at least one (meth)acryloyloxy group in the molecule; (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.

The pressure-sensitive adhesive composition may further contain a silane compound. By containing the silane compound, the adhesion between the pressure-sensitive adhesive layer and the layer to be laminated can be improved. You may use two or more types of silane compounds.

As the silane compound, for example, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris(2-methoxyethoxy)silane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl tri Ethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl ethoxydimethylsilane, 2-(3, 4-epoxy cyclohexyl) ethyl trimethoxysilane, 3-chloropropyl methyldimethoxy Silane, 3-chloropropyl trimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, etc. are mentioned.

Further, the silane compound may include an oligomer derived from the silane compound.

The content of the silane compound in the pressure-sensitive adhesive composition is usually 0.01 parts by mass or more and 10 parts by mass or less, preferably 0.03 parts by mass or more and 5 parts by mass or less, and more preferably 0.05 parts by mass with respect to 100 parts by mass of the base polymer. It is more than 2 mass parts, More preferably, it is 0.1 mass part or more and 1 mass part or less.

The adhesive composition includes fine particles to impart light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, tackifiers, fillers (metal powders or other inorganic powders, etc.), antioxidants, ultraviolet absorbers. , Dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, may contain additives such as photopolymerization initiators.

The pressure-sensitive adhesive layer can be formed by applying a diluent of the pressure-sensitive adhesive composition, for example, an organic solvent on a substrate and drying it. When an active energy ray-curable pressure-sensitive adhesive composition is used, a cured product having a desired degree of curing can be obtained by irradiating the formed pressure-sensitive adhesive layer with an active energy ray.

The thickness of the pressure-sensitive adhesive layer may be, for example, 1 μm or more and 100 μm or less, preferably 2 μm or more and 70 μm or less, and more preferably 3 μm or more and 50 μm or less.

[Lamination layer]

The bonding layer is a layer that functions to bond the structure 1 to each other, or further bonds the optical member to the structure 1. For the bonding layer, an adhesive may be used or an adhesive may be used. As the adhesive used for the bonding layer, an adhesive composition used for the adhesive layer can be used. As the adhesive, a water-based adhesive or an active energy ray-curable adhesive can be used. Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, an aqueous two-component urethane emulsion adhesive, and the like. When the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer is used for the bonding layer, the bonding layer satisfies the above-described formula (i). On the other hand, when an adhesive layer is used for the pressure-sensitive adhesive layer, the bonding layer may or may not satisfy the above-described formula (i).

The active energy ray-curable adhesive refers to an adhesive that is cured by irradiation with an active energy ray such as ultraviolet rays, and includes, for example, a polymerizable compound and a photopolymerization initiator, a photoreactive resin, a binder resin and a light The thing containing a reactive crosslinking agent, etc. are mentioned.

Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers, and oligomers derived from photopolymerizable monomers.

Examples of the photopolymerization initiator include those containing substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals by irradiation with active energy rays such as ultraviolet rays. As an active energy ray-curable adhesive containing a polymerizable compound and a photoinitiator, one containing a photocurable epoxy monomer and a photocationic polymerization initiator can be preferably used.

<Method of manufacturing laminate>

The method of manufacturing the laminate is described with reference to the drawings. The embodiment shown in Fig. 4 includes the following steps.

1) Process of preparing the front plate 11 (Fig. 4(a))

2) Process of forming the adhesive layer 21 on the front plate 11 (Fig. 4(b))

3) Process of bonding the polarizing plate 12 to the side opposite to the front plate 11 side of the adhesive layer 21 (Fig. 4(c))

4) A pressure-sensitive adhesive layer 22 is formed on the side of the polarizing plate 12 opposite to the side of the pressure-sensitive adhesive 11, and the touch sensor panel 13 is attached on the side of the pressure-sensitive adhesive layer 22 opposite to the side of the polarizing plate 12. Combined process (Fig. 4(d))

5) A pressure-sensitive adhesive layer 23 is formed on the side opposite to the side of the pressure-sensitive adhesive layer 22 of the touch sensor panel 13, and an organic EL display is formed on the side of the pressure-sensitive adhesive layer 23 opposite to the side of the touch sensor panel 13 Step of bonding the elements 14 (Fig. 4(e))

When bonding the pressure-sensitive adhesive layer and each optical member, treatments such as corona treatment and plasma treatment may be performed on the bonding surface.

The pressure-sensitive adhesive layer is prepared by dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive solution, and a layer made of the pressure-sensitive adhesive is formed in a sheet shape on the release film subjected to the release treatment. It can be formed by preparing a pressure-sensitive adhesive sheet by further bonding another release film on the pressure-sensitive adhesive layer, removing the release film from the pressure-sensitive adhesive sheet, bonding to the optical member, and removing the remaining release film.

<Image display device>

The image display device according to the present invention includes the laminate according to the present invention. The image display device is not particularly limited, and examples thereof include image display devices such as an organic EL display device, an inorganic EL display device, a liquid crystal display device, and an electroluminescent display device. The image display device may have a contact panel function. The laminate is very suitable for an image display device having flexibility capable of bending or folding. In the image display apparatus, when the laminate has a front plate, the laminate is disposed on the visual recognition side of the image display apparatus with the front plate facing the outside (the side opposite to the image display device element side, that is, the viewer side).

The image display device according to the present invention can be used as a mobile device such as a smart phone or a tablet, a television, a digital photo frame, an electronic signboard, a measuring device or instrument, an office device, a medical device, a computer device, and the like. The image display device according to the present invention has excellent flexibility, so it is very suitable for flexible displays.

Examples and comparative examples are shown to describe the present invention more specifically, but the present invention is not limited by these examples. In the examples, "%" and "parts" are mass% and mass parts unless otherwise specified. Tests and measurements were performed as follows.

(Example)

[Evaluation of flexibility]

A bending evaluation facility (manufactured by Yuasa System Co., Ltd., a planar body no-load U-shaped stretch test: DLDMLH-FS) was used. 5 is a diagram schematically showing this evaluation test method. As shown in Fig. 5, two mounting tables 501 and 502 that can be moved individually are arranged so that the gap C becomes 5.0 mm (2.5R), and the center of the width direction is located at the center of the gap C. The laminate was fixed so as to be arranged (Fig. 5(a)). At this time, the laminate was disposed so that the front plate was upward. Then, the two mounting tables 501 and 502 are rotated 90 degrees upward with the position P1 and the position P2 as the center of the rotation axis, and the bending force is applied to the region of the laminate corresponding to the gap C of the mounting table. Was added (Fig. 5(b)). Thereafter, the two mounting tables 501 and 502 were returned to their original positions (Fig. 5(a)). After the above series of operations were completed, the number of times the bending force was added was counted once. After this was repeatedly performed at room temperature, it was confirmed whether or not cracks occurred in the region corresponding to the gap C of the mounting tables 501 and 502 of the laminate. The moving speeds of the mounting tables 501 and 502 and the additional pace (90 times/min) of the bending force were the same conditions in the evaluation test for any laminated body. Each of the laminates after bending each laminate was counted for the number of flexures in which cracks occurred.

[Measurement method of thickness]

In the same bendability test as above, the center of the stack in the width direction (bent portion) of the stacked body when the number of bends was performed 10,000 times and the stacked body before performing this bendability test was sliced with a microtome in a direction perpendicular to the width direction. , The cross section was observed using a transmission electron microscope (SU8010; HORIBA, Ltd.), and the thickness of each layer was measured from the obtained observation image.

[Thickness change rate per unit bending number]

From the thickness of the pressure-sensitive adhesive layer (T ₀ ) before performing the flexibility evaluation obtained as described above and the thickness of the pressure-sensitive adhesive layer (T ₁ ) when the number of bends is performed 10,000 times, according to the equation below, The rate of change [%/ten thousand times] was calculated.

Rate of change in thickness per unit bending number [%/ _ten thousand times] = ｜T ₁ -T ₀ ｜／T ₀ ×100

[Measurement method of storage modulus]

The storage modulus of the pressure-sensitive adhesive layer at a temperature of 25° C. was measured using a viscoelasticity measuring device (MCR-301, Anton Paar). A pressure-sensitive adhesive sheet having a thickness of 25 μm, similar to that used in Examples and Comparative Examples, was cut into a width of 30 mm x a length of 30 mm. Peel off the release film, laminate a plurality of sheets to a thickness of 150 μm, bond to a glass plate, and adhere to the measuring chip in a temperature range of -20°C to 100°C with a frequency of 1.0 Hz, strain 1%, and a heating rate of 5°C The measurement was performed under the condition of /min, and the storage modulus at a temperature of 25°C was measured.

[Measurement method of recovery]

Recovery was measured using a viscoelasticity measuring device (MCR-301, Anton Paar). An adhesive sheet having a thickness of 25 μm similar to that used in Examples and Comparative Examples was cut into a width of 20 mm × 20 mm in length, the release film was peeled off, and a plurality of sheets were laminated so as to have a thickness of 200 μm, and bonded to a glass plate. The measurement was performed under a load condition of 1200 μNm of torque at a temperature of 25°C in a state of being bonded to the measurement chip, and after measuring the amount of shear deformation at 1200 seconds, change to a condition of 0 μNm of torque to continue the measurement, and at 1206 seconds. The amount of shear deformation was measured. Based on these measured values, the recovery R ₀ [%] was calculated by the following equation.

R ₀ [%] = (1200 sec shear strain-1206 sec shear strain)/1200 sec shear strain×100

<Production Example 1>

A mixed solution of 81.8 parts of acetone, 98.4 parts of butyl acrylate, 0.6 parts of acrylic acid, and 1.0 part of acrylic acid 2-hydroxyethyl was prepared in a reactor equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, and nitrogen gas was used in the apparatus. The internal temperature was raised to 55° C. while air was replaced and oxygen was not included. Thereafter, the total amount of a solution in which 0.14 parts of azobisisobutyronitrile (polymerization initiator) was dissolved in 10 parts of acetone was added. 1 hour after the initiator was added, acetone was continuously added to the reactor at an addition rate of 17.3 parts/hr so that the concentration of the acrylic resin excluding the monomer was 35%, while keeping the temperature at an internal temperature of 54 to 56°C for 12 hours, and finally acetic acid Ethyl was added, and the concentration of the acrylic resin was adjusted to 20%. The obtained acrylic resin had a weight average molecular weight (Mw) of 1,650,000 and Mw/Mn of 4.3.

<Production Example 2>

An acrylic resin solution was obtained in the same manner as in Production Example 1 except that the monomer composition was changed to 0.4 parts of acrylic acid. The obtained acrylic resin had Mw of 1, 270, 000 and Mw/Mn of 5.0.

<Production Example 3>

In a reactor equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, a mixed solution of 100 parts of ethyl acetate, 98.9 parts of butyl acrylate, and 1.1 parts of acrylic acid was prepared, and the air in the device was replaced with nitrogen gas to remove oxygen, while azo The total amount of the solution in which 0.2 parts of bisisobutyronitrile was dissolved in 10 parts of ethyl acetate was added, and the inner temperature was raised to 70°C for 6 hours, followed by heating to 70°C for 2 hours. Then, a solution in which 0.4 parts of azobisisobutyronitrile was dissolved in 20 parts of ethyl acetate was added dropwise over 1 hour, and ethyl acetate was further added to adjust the acrylic resin concentration to 20%. The viscosity of the obtained acrylic resin solution was 9.8 Pa·s, and this acrylic resin had a weight average molecular weight (Mw) of 710,000 and Mw/Mn of 12.0.

<Production Example 4>

Except having changed the monomer composition to 0.6 parts of acrylic acid, it carried out similarly to manufacture example 3, and obtained the acrylic resin solution. The obtained acrylic resin had a weight average molecular weight (Mw) of 710, 000 and Mw/Mn of 12.

<Production Example 5>

Except having changed the monomer composition to 0.5 part of acrylic acid, it carried out similarly to manufacture example 3, and obtained the acrylic resin solution. The obtained acrylic resin had a weight average molecular weight (Mw) of 710, 000 and Mw/Mn of 12.

(1) Preparation of pressure-sensitive adhesive composition

<Preparation of adhesive composition (A)>

With respect to 100 parts of solid content of acrylic resin [acrylic resin obtained in Preparation Example 1], polyisocyanate compound [Colonate L: ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content 75%), Nippon Polyurethane Industry Co., Ltd.] 0.5 parts and 0.5 parts of silane compounds [KBM403, 3-glycidoxypropyltrimethoxysilane, obtained from Shin-Etsu Chemical Co., Ltd.] were mixed. Ethyl acetate was added so that the total solid content concentration became 10%, and the adhesive composition (A) was obtained.

<Preparation of adhesive composition (B)>

Except having used the acrylic resin as the acrylic resin obtained in Production Example 2 and using 0.4 parts of the polyisocyanate compound, it carried out similarly to preparation of the adhesive composition (A), and obtained the adhesive composition (B).

<Preparation of adhesive composition (C)>

Except having used the acrylic resin as the acrylic resin obtained in Production Example 3 and using the polyisocyanate compound as 0.05 parts, it carried out similarly to the preparation of the adhesive composition (A), and obtained the adhesive composition (C).

<Preparation of adhesive composition (D)>

Except having used the acrylic resin as the acrylic resin obtained in Production Example 4, it carried out similarly to preparation of the adhesive composition (A), and obtained the adhesive composition (D).

<Preparation of adhesive composition (E)>

A pressure-sensitive adhesive composition (E) was obtained in the same manner as in the preparation of the pressure-sensitive adhesive composition (A), except that the acrylic resin was used as the acrylic resin obtained in Production Example 5 and the polyisocyanate compound was set to 0.03 parts.

<Preparation of adhesive composition (F)>

A pressure-sensitive adhesive composition (F) was obtained in the same manner as in the preparation of the pressure-sensitive adhesive composition (A), except that the acrylic resin was used as the acrylic resin obtained in Production Example 5 and the polyisocyanate compound was set to 0.02 parts.

(2) Preparation of adhesive sheet

The pressure-sensitive adhesive composition (A) was applied to a release-treated surface of a release-treated polyethylene terephthalate film (38 μm in thickness) so that the thickness after drying with an applicator became 25 μm or 5 μm. The coating layer was dried at 100° C. for 1 minute to obtain a film including an adhesive layer (A) having a thickness of 25 μm or 5 μm. Thereafter, another polyethylene terephthalate film (38 μm in thickness) subjected to a release treatment was pasted onto the pressure-sensitive adhesive layer. Then, it was cured for 7 days under the conditions of a temperature of 23°C and a relative humidity of 50%RH.

In this way, an adhesive sheet (A) composed of a release film (A)/adhesive layer (A)/a release film (B) was produced.

Except having replaced the adhesive composition (A) with the adhesive compositions (B)-(F), it carried out similarly, respectively, and produced the adhesive sheets (B)-(F). Storage modulus and recovery were measured for each adhesive sheet. Table 1 shows the results.

(3) Fabrication of polarizing plate

A photo-alignment layer was formed on the triacetylcellulose (TAC) film (thickness 25 μm). A composition containing a dichroic dye and a polymerizable liquid crystal compound was applied to the photoalignment layer, aligned, and cured to obtain a polarizer having a thickness of 2 μm. A resin composition containing polyvinyl alcohol and water was coated on the polarizer so that the thickness after drying became 1.0 μm, and dried at 80° C. for 3 minutes to form an overcoat layer to obtain a polarizing plate.

(4) Optical member

The following optical members were used. The dimensions of each optical member were the same as the front plate.

Front plate: Front plate with hard coat layers (10 μm thick) formed on both sides of a base film (polyimide resin film, thickness 50 μm) (70 μm thick, 110 mmm long × 20 mm horizontal)

Polarizing plate: The polarizing plate described above (about 28 μm thick)

Retardation film: A retardation film comprising a layer cured by polymerization of a liquid crystal compound [thickness 11 μm, layer structure: λ/4 plate (thickness 3 μm) consisting of a layer and alignment film cured with a liquid crystal compound (thickness 3 μm)/adhesive layer (thickness 5 μm)/liquid crystal Positive (C) plate (thickness 3 μm) consisting of a compound-cured layer and an alignment film]

Touch sensor panel: 33μm thick, layer composition: touch sensor pattern (stacked product of ITO and cured layer of acrylic resin composition, 7μm thick)/adhesive layer (thick 3μm)/cyclic olefin resin film (23μm thick)

Organic EL panel: 38μm thick

<Example 1>

Corona treatment was performed on the bonding surface of the front plate with the pressure-sensitive adhesive layer and the bonding surface of the first adhesive layer comprising the pressure-sensitive adhesive layer (A) having a thickness of 25 μm described above with the front plate. Then, the front plate and the first adhesive layer were bonded to each other to obtain a front plate having an adhesive layer.

The above-described retardation film was bonded to the surface of the overcoat layer of the above-described polarizing plate through a second adhesive layer composed of a pressure-sensitive adhesive layer (A) having a thickness of 5 μm, and a circular polarizing plate (thickness 43.5 μm) was prepared.

Thereafter, the front plate and circular polarizing plate having an adhesive layer were subjected to corona treatment on the side on which the pressure-sensitive adhesive layer of the front plate was formed and the surface on the TAC side of the circular polarizing plate, and then laminated so that these surfaces were inside, and rolled They were bonded together using a bonding machine. Moreover, on the surface of the circular polarizing plate opposite to the side where the front plate could be bonded, the touch sensor panel was formed through the third adhesive layer made of the adhesive layer (A) having a thickness of 25 μm described above, and the cyclic olefin resin film was formed on the surface. It was laminated so that

Subsequently, the organic EL panel was bonded to the surface on the side of the cyclic olefin resin film through the fourth adhesive layer comprising the adhesive layer (A) having a thickness of 25 μm described above. Table 2 shows the evaluation results for the obtained laminate.

<Example 2>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer in Example 1, the first adhesive layer, the second adhesive layer, and the third adhesive layer And a laminate of Example 2 was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive layer (B) was used for the fourth adhesive layer. Table 2 shows the evaluation results for the obtained laminate.

<Example 3>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer in Example 1, the first adhesive layer, the second adhesive layer, and the third adhesive layer And a laminate of Example 3 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (C) was used for the fourth adhesive layer. Table 2 shows the evaluation results for the obtained laminate.

<Example 4>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer and the fourth adhesive layer in Example 1, the first adhesive layer, the third adhesive layer, and the fourth adhesive layer In the same manner as in Example 1, except that the pressure-sensitive adhesive layer (C) was used and the pressure-sensitive adhesive layer (D) was used as the second adhesive layer, a laminate of Example 4 was produced. Table 2 shows the evaluation results for the obtained laminate.

<Example 5>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer in Example 1, the first adhesive layer, the second adhesive layer, and the third adhesive layer And a laminate of Example 5 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (D) was used for the fourth adhesive layer. Table 2 shows the evaluation results for the obtained laminate.

<Example 6>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer in Example 1, the first adhesive layer, the second adhesive layer, and the third adhesive layer And a laminate of Example 6 was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (E) was used for the fourth adhesive layer. Table 2 shows the evaluation results for the obtained laminate.

<Comparative Example 1>

Instead of using the adhesive layer (A) for the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer in Example 1, the first adhesive layer, the second adhesive layer, and the third adhesive layer And a laminate of Comparative Example 1 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (F) was used for the fourth adhesive layer. Table 2 shows the evaluation results for the obtained laminate.

1, 4, 7, 100: laminate
2, 5, 8: optical member
3, 6, 9, 21, 22, 23: adhesive layer
10: bonding layer
11: front panel
12: polarizer
13: Touch sensor panel
14: organic EL display device
501, 502: tact

Claims (6)

A laminate comprising at least one structure in which the optical members are laminated to each other through an adhesive layer, and in at least one of the structures, the adhesive layer satisfies the following formula (i).
Rate of change in thickness per unit bending number [%/10,000 times] <10 (i) The method of claim 1,
The thickness of the pressure-sensitive adhesive layer satisfying the above formula (i) is 5 μm or more. The method according to claim 1 or 2,
In the above structure, all of the pressure-sensitive adhesive layers satisfy the formula (i). The method according to any one of claims 1 to 3,
The structure in which the optical members are stacked with each other through an adhesive layer is a structure in which two optical members selected from the group consisting of a front plate, a polarizing plate, a touch sensor panel, an organic EL display device, and a retardation film are stacked through the adhesive layer. Phosphorus, laminate. An image display device comprising the laminate according to any one of claims 1 to 4. The method of claim 5,
An image display device having flexibility.

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