JP6859383B2 - Laminated body and image display device - Google Patents

Description

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

Patent Document 1 proposes that in an image display device having an image display panel, an adhesive layer, and a flexible film in this order, the adhesive layer is arranged at a distance from the image display panel in a bent region.

Korean Published Patent 10-2016-0069560

A laminate provided with a front plate and a circularly polarizing plate having adhesive layers on both sides is placed in a bent state in a high temperature and high humidity environment, and then when released from the bent state, it becomes a bent portion. Waviness may occur. This swell may reduce the smoothness of the surface. When the smoothness of the surface is lowered, for example, the reflected image is distorted and the visibility is lowered. An object of the present invention is an object of a bendable laminate provided with a front plate and a circularly polarizing plate having adhesive layers on both sides, in a state of being bent in a high temperature and high humidity environment with the front plate side inside for a long time. It is an object of the present invention to provide a laminate having small waviness on the surface on the front plate side and having excellent visibility even after being placed, and an image display device provided with the laminate.

The present invention provides the following laminate and image display device.
[1] A front plate and a circularly polarizing plate with a double-sided adhesive layer are provided, and the thickness of the front plate is a [μm] and the thickness of the circularly polarizing plate with a double-sided adhesive layer is b [μm]. A laminate that satisfies the following formula (1) when the tensile elastic modulus at a front plate temperature of 60 ° C. and a relative humidity of 90% RH is c [MPa].
[(B / a) × c] ≧ 2200 (1)
[2] The laminate according to [1], wherein the a and c satisfy the following formula (2).
a / c ≤ 0.03 (2)
[3] The laminate according to [1] or [2], wherein the front plate has a hard coat layer.
[4] The circularly polarizing plate with a double-sided pressure-sensitive adhesive layer has a first pressure-sensitive adhesive layer, a linear polarizing plate, a retardation layer, and a second pressure-sensitive adhesive layer in this order. The laminate according to any one.
[5] The laminate according to [4], wherein the linear polarizing plate includes a thermoplastic resin film having a hard coat layer on at least one surface.
[6] An image display device comprising the laminate according to any one of [1] to [5].

According to the present invention, in a bendable laminate provided with a front plate and a circular polarizing plate having adhesive layers on both sides, the front plate side is turned inside and the laminated body is bent in a high temperature and high humidity environment for a long time. It is possible to provide a laminate having a small waviness on the surface on the front plate side and having excellent visibility even after being placed, and an image display device provided with the laminate.

It is a schematic sectional drawing which shows the laminated body which concerns on one aspect of this invention. It is a schematic sectional drawing which shows the laminated body which concerns on one aspect of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, the scale is appropriately adjusted to make it easier to understand each component, and the scale of each component shown in the drawings does not necessarily match the scale of the actual component.

<Laminated body>
FIG. 1 is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. The optical laminate 100 shown in FIG. 1 includes a front plate 10 and a circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer.

The laminate 100 can be bent at least in the direction in which the front plate 10 is inside. Bendable means that the front plate 10 can be bent in the direction inward without causing cracks.

The thickness of the front plate 10 is a [μm], the thickness of the circular polarizing plate 20 with a double-sided pressure-sensitive adhesive layer is b [μm], and the tensile elastic modulus of the front plate 10 at a temperature of 60 ° C. and a relative humidity of 90% RH (hereinafter omitted). When c [MPa] is set (sometimes referred to as “tensile elastic modulus”), the laminated body 100 satisfies the following formula (1). In the present specification, the tensile elastic modulus refers to a value measured in an environment of a temperature of 60 ° C. and a relative humidity of 90% RH, unless otherwise specified.
[(B / a) × c] ≧ 2200 (1)

By satisfying the formula (1), the laminated body 100 is placed on the surface of the front plate 10 side in the bent portion even after being left for a long time in a state of being bent in a high temperature and high humidity environment with the front plate 10 inside. The generated swell is suppressed, and uniform visibility can be ensured. The front plate 10 and the circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer are selected so as to satisfy the above formula (1). The laminate 100 preferably satisfies the following formula (1a), and more preferably the following formula (1b), from the viewpoint of improving the waviness of the surface.
[(B / a) × c] ≧ 3000 (1a)
[(B / a) × c] ≧ 4000 (1b)
Further, the laminated body 100 preferably satisfies the following formula (1c).
[(B / a) × c] ≦ 10000 (1c)

A portion of a laminate having a front plate and a circularly polarizing plate with a double-sided pressure-sensitive adhesive layer, which is bent by the present inventor in a high-temperature and high-humidity environment with the front plate inside, and then bent. It was found that undulations may occur on the surface of the front plate side, and uniform visibility may not be ensured. As a result of the research, the thickness of the front plate, the thickness of the circularly polarizing plate with the double-sided adhesive layer, and the thickness of the front plate so that the laminate provided with the front plate and the circularly polarizing plate with the double-sided adhesive layer satisfies the formula (1). It has been found that the above-mentioned waviness can be suppressed by adjusting the tensile elastic modulus.

In the present specification, the tensile modulus is measured by the method described in the column of Examples described later.

In the laminated body 100, a and c preferably satisfy the following formula (2) from the viewpoint of suppressing waviness.
a / c ≤ 0.03 (2)

The laminate 100 more preferably satisfies the following formula (2a) from the viewpoint of suppressing waviness.
a / c ≤ 0.02 (2a)

The laminate 100 preferably satisfies the following formula (2b) from the viewpoint of suppressing waviness.
a / c ≧ 0.009 (2b)

The shape of the laminated body 100 in the plane direction may be, for example, a rectangular shape, preferably a rectangular shape having a long side and a short side, and more preferably a rectangular shape. When the shape of the laminate 100 in the plane direction is rectangular, the length of the long side may be, for example, 10 mm or more and 1400 mm or less, preferably 50 mm or more and 600 mm or less. The length of the short side is, for example, 5 mm or more and 800 mm or less, preferably 30 mm or more and 500 mm or less, and more preferably 50 mm or more and 300 mm or less. Each layer constituting the laminated body 100 may have corners R-processed, end portions notched, or perforated.

The thickness of the laminate 100 is not particularly limited because it varies depending on the function required for the laminate, the application of the laminate, etc., but is, for example, 20 μm or more and 500 μm or less, preferably 50 μm or more and 300 μm or less, and more preferably 70 μm or more and 200 μm. It is as follows.

The laminated body 100 can be used, for example, in a display device or the like. The display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, and an electroluminescent display device. The laminated body 100 is suitable for a flexible display because the waviness after bending is suppressed.

[Front plate]
The front plate 10 can be a plate-like body capable of transmitting light. The front plate 10 may be composed of only one layer, or may be composed of two or more layers. Examples thereof include a resin plate-like body (for example, a resin plate, a resin sheet, a resin film, etc.), a glass plate-like body (for example, a glass plate, a glass film, etc.) and the like. The front plate can be a layer constituting the outermost surface of the display device.

The thickness a [μm] of the front plate 10 may be, for example, 10 μm or more and 100 μm or less, preferably 20 μm or more and 85 μm or less, and more preferably 30 μm or more, from the viewpoint of suppressing waviness after bending and reducing the thickness of the laminated body. It is 70 μm or less. In the present invention, the thickness of each layer can be measured according to the thickness measuring method described in the column of Examples described later.

The tensile elastic modulus c [MPa] of the front plate 10 at a temperature of 60 ° C. and a relative humidity of 90% RH may be, for example, 1500 MPa or more, preferably 2000 MPa or more and 10000 MPa or less, more preferably from the viewpoint of suppressing waviness after bending. It is 2000 MPa or more and 6000 MPa or less. The tensile elastic modulus is determined by, for example, selection of the material and thickness of the plate-like body constituting the front plate, selection of the composition for forming the hard coat layer for forming the hard coat layer described later, selection of the thickness of the cured product thereof, and these. The combination can be adjusted to the above range.

When the front plate 10 is a resin plate-like body, the resin plate-like body can be, for example, a resin film capable of transmitting light. Examples of the thermoplastic resin constituting the resin plate such as a resin film include a chain polyolefin resin (polyethylene resin, polypropylene resin, polymethylpentene resin, etc.) and a cyclic polyolefin resin (norbornen type). Resins, etc.) Polyethylene-based resins; Cellulosic resins such as triacetyl cellulose; Polyester-based resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; Polycarbonate-based resins; Ethylene-vinyl acetate resins; Polystyrene-based resins; Polyamide Based resin; polyetherimide based resin; (meth) acrylic resin such as polymethyl (meth) acrylate resin; polyimide resin; polyether sulfone resin; polysulfone resin; polyvinyl chloride resin; polyvinylidene chloride resin; Examples thereof include polyvinyl alcohol-based resins; polyvinyl acetal-based resins; polyether ketone-based resins; polyether ether ketone-based resins; polyether sulfone-based resins; polyamideimide-based resins. The thermoplastic resin can be used alone or in combination of two or more.
Among them, the thermoplastic resin constituting the front plate is preferably a cyclic polyolefin resin, a polyimide resin, a polyamide resin, or a polyamide-imide resin from the viewpoint of flexibility, strength and transparency, and more preferably polyamide. It is an imide-based tree. Specific examples of the polyamide-imide resin include the polyamide-imide film described in JP-A-2018-119141.

The front plate 10 can be a film in which a hard coat layer is provided on at least one surface of the base film. As the base film, a film made of the above resin can be used. The hard coat layer may be formed on one surface of the base film or may be formed on both surfaces. By providing the hard coat layer, a resin film having improved hardness and scratchability can be obtained.

The hard coat layer can be formed from a cured product of a hard coat layer forming composition (hereinafter, also referred to as an HC layer forming composition) containing an active energy ray-curable resin. Examples of the ultraviolet curable resin include acrylic resin, silicone resin, polyester resin, urethane resin, amide resin, epoxy resin and the like. The hard coat layer may contain additives to improve strength. Additives are not limited, and include inorganic fine particles, organic fine particles, or mixtures thereof. The composition for forming an HC layer can be prepared according to the method described in, for example, Korean Patent Publication No. 10-2018-0127050.

When the front plate 10 is a glass plate, tempered glass for a display is preferably used as the glass plate. By using the glass plate, the front plate 10 having excellent mechanical strength and surface hardness can be constructed.

When the optical laminate 100 is used in a display device, the front plate 10 not only has a function of protecting the front surface (screen) of the display device (function as a window film), but also has a touch detected by the touch sensor panel 30. It may also have a function as an operation surface for performing the above, and may further have a blue light cut function, a viewing angle adjusting function, and the like.

[Circular polarizing plate with double-sided adhesive layer]
The circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer preferably includes a first pressure-sensitive adhesive layer, a linear polarizing plate, a retardation layer, and a second pressure-sensitive adhesive layer in this order. In this embodiment, the thickness of the circularly polarizing plate 20 with the double-sided pressure-sensitive adhesive layer is from the surface of the first pressure-sensitive adhesive layer opposite to the linear polarizing plate side to the side opposite to the linear polarizing plate side of the second pressure-sensitive adhesive layer. Can be the distance to the surface of. A circularly polarizing plate in which a linearly polarized light layer and a retardation layer are arranged so that the absorption axis of the linearly polarizing plate and the slow axis of the retardation layer are at a predetermined angle can exhibit an antireflection function. When the retardation layer includes the λ / 4 plate, the angle formed by the absorption axis of the linear polarizing plate and the slow axis of the λ / 4 plate can be 45 ° ± 10 °. The linear polarizing plate and the retardation layer may be bonded by a bonding layer described later. Hereinafter, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be collectively referred to as a pressure-sensitive adhesive layer.

The thickness b of the circularly polarizing plate 20 with the double-sided pressure-sensitive adhesive layer may be, for example, 10 μm or more and 200 μm or less, preferably 15 μm or more and 150 μm or less, and more preferably 20 μm or more and 100 μm or less.

(Linear polarizing plate)
Examples of the linear polarizing plate include a stretched film or a stretched layer on which a dye having absorption anisotropy is adsorbed, a film containing a film coated with a dye having absorption anisotropy and cured, and the like as a polarizer. Examples of the dye having absorption anisotropy include a dichroic dye. Specifically, as the dichroic dye, iodine or a dichroic organic dye is used. For dichroic organic dyes, C.I. I. Included are dichroic direct dyes made of disuazo compounds such as DIRECT RED 39 and dichroic direct dyes made of compounds such as trisazo and tetrakisazo.

As a film to which a dye having absorption anisotropy is applied and cured, which is used as a polarizer, a composition containing a dichroic dye having a liquid crystal property or a composition containing a dichroic dye and a polymerizable liquid crystal is used. Examples thereof include a film containing a cured product of a polymerizable liquid crystal compound such as a layer obtained by coating and curing. A film coated with a dye having absorption anisotropy and cured is preferable because there is no limitation in the bending direction as compared with a stretched film or a stretched layer on which a dye having absorption anisotropy is adsorbed.

The linear polarizing plate may be composed of only a polarizing element, or may further include a protective layer, a thermoplastic resin film, a base material, an alignment film, and a protective layer, which will be described later, in addition to the polarizing element. The thickness of the linear polarizing plate is, for example, 2 μm or more and 100 μm or less, preferably 10 μm or more and 60 μm or less.

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

The polyvinyl alcohol-based resin is obtained by saponifying the polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (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, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 or more and 10000 or less, preferably 1500 or more and 5000 or less.

Next, a linear polarizing plate including a stretched layer on which a dye having absorption anisotropy is adsorbed as a polarizer will be described. The stretched layer on which the dye having absorption anisotropy, which is a polarizer, is adsorbed is usually a step of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, and uniaxially stretching the obtained laminated film. Step, A step of dyeing a polyvinyl alcohol-based resin layer of a uniaxially stretched laminated film with a bicolor dye to adsorb the bicolor dye to form a polarizer, a film on which the bicolor dye is adsorbed It can be produced through a step of treating with an aqueous boric acid solution and a step of washing with water after treatment with an aqueous boric acid solution.
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 polarizing film, which is a stretched film or a stretched layer, may be incorporated into the laminate in a form in which a thermoplastic resin film is bonded to one side or both sides thereof. This thermoplastic resin film can function as a protective film for a polarizer or a retardation film. The thermoplastic resin film is, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin, etc.), a cyclic polyolefin resin (norbornen resin, etc.); a cellulose resin such as triacetyl cellulose; polyethylene terephthalate, polyethylene na. A film made of a polyester resin such as phthalate or polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin; or a mixture thereof can be used.

From the viewpoint of thinning, the thickness of the thermoplastic resin film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, still more preferably 60 μm or less. Yes, it is usually 5 μm or more, preferably 20 μm or more. The thermoplastic resin film may or may not have a phase difference. The thermoplastic resin film can be attached to the polarizer using, for example, an adhesive layer.

(2) A linear polarizing plate having a film coated with a dye having absorption anisotropy and cured as a polarizer A linear polarizing plate having a film coated with a dye having absorption anisotropy and cured as a polarizer will be described. .. A film to which a dye having absorption anisotropy is applied and cured, which is used as a polarizer, is based on a composition containing a dichroic dye having liquid crystal properties or a composition containing a dichroic dye and a liquid crystal compound. Examples thereof include a film obtained by applying it to a material and curing it. The film may be used as a linear polarizing plate by peeling off the base material or together with the base material, or may be used as a linear polarizing plate in a configuration having a thermoplastic resin film on one side or both sides thereof.

The base material may be a thermoplastic resin film. The example and thickness of the base material may be the same as those exemplified in the above description of the thermoplastic resin film. The base material may be a thermoplastic resin film having a hard coat layer, an antireflection layer, or an antistatic layer on at least one surface. The base material may have a hard coat layer, an antireflection layer, an antistatic layer, or the like formed only on the surface on the side where the polarizer is not formed. As the base material, the hard coat layer, the antireflection layer, the antistatic layer and the like may be formed only on the surface on the side where the polarizer is formed. The example of the hard coat layer is the same as the example of the composition for forming the HC layer in the above description of the front plate.

Examples of the thermoplastic resin film include the same one as the linear polarizing plate provided with the stretched film or the stretched layer as a polarizer. The thermoplastic resin film can be attached to the polarizer using, for example, an adhesive layer.

It is preferable that the film coated with the dye having absorption anisotropy and cured is thin, but if it is too thin, the strength is lowered and the processability tends to be inferior. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 μm or more and 3 μm or less.

Specific examples of the film coated with the dye having absorption anisotropy and cured include those described in JP-A-2013-373353 and JP-A-2013-33249.

(Alignment film)
The alignment film can be arranged between the base material and a composition containing a dichroic dye having a liquid crystal property, or a layer of a cured product of the composition containing the dichroic dye and a liquid crystal compound. The alignment film has an orientation regulating force that aligns the liquid crystal layer formed on the liquid crystal layer in a desired direction. Examples of the alignment film include an orientation polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a grub alignment film having an uneven pattern or a plurality of grubs (grooves) on the layer surface. Can be done. The thickness of the alignment film may be, for example, 10 nm or more and 500 nm or less, and preferably 10 nm or more and 200 nm or less.

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

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

The grub alignment film is used, for example, in a method of forming a concavo-convex pattern by exposing, developing, or the like through an exposure mask having a pattern-shaped slit on the surface of a photosensitive polyimide film, and is active on a plate-shaped master having a groove on the surface. A method of forming an uncured layer of an energy ray-curable resin, transferring this layer to a substrate and curing it, forming an uncured layer of an active energy ray-curable resin on the substrate, and making this layer uneven. It can be formed by a method of forming irregularities and hardening by pressing a roll-shaped master having the above.

(Protective layer)
The protective layer can be used to protect the surface of the polarizer. When the linear polarizing plate contains a thermoplastic resin film, the protective layer can be arranged on the opposite side of the polarizing element from the thermoplastic resin film. The protective layer may be formed from the resin film exemplified as the material of the above-mentioned thermoplastic resin film, or may be a coating type protective layer. The coating type protective layer may be formed by applying a cationic curable composition such as an epoxy resin or a radical curable composition such as (meth) acrylate and curing it, and may be an aqueous solution of a polyvinyl alcohol-based resin or the like. It may be coated and dried, and if necessary, a plasticizer, an ultraviolet absorber, an infrared absorber, a colorant such as a pigment or a dye, an optical brightener, a dispersant, a heat stabilizer, and a light stabilizer. It may contain an agent, an antioxidant, an antioxidant, a lubricant, and the like.

The thickness of the protective layer may be, for example, 200 μm or less, preferably 0.1 μm or more and 100 μm or less.

(Phase difference layer)
The retardation layer may include one layer or two or more retardation layers. The retardation layer can be a positive A layer such as a λ / 4 layer or a λ / 2 layer, and a positive C layer. The retardation layer may be formed from the resin film exemplified as the material of the above-mentioned thermoplastic resin film, or may be formed from a layer in which the polymerizable liquid crystal compound is cured. The retardation layer may further include an alignment film and a base material. The thickness of the retardation layer may be, for example, 1 μm or more and 50 μm or less.

(Adhesive layer)
The first pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer included in the circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer. The first pressure-sensitive adhesive layer is arranged to bond the circularly polarizing plate 20 with the double-sided pressure-sensitive adhesive layer and the front plate 10. The second pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer included in the circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer. The second pressure-sensitive adhesive layer is arranged to bond the circularly polarizing plate 20 with the double-sided pressure-sensitive adhesive layer and the back plate described later. The pressure-sensitive adhesive layer can be formed by using the pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer may have a single-layer structure or a multi-layer structure, but is preferably a single-layer structure. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may each be composed of the same type of pressure-sensitive adhesive layer, or may be composed of different types of pressure-sensitive adhesive layers.

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

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, and hexyl (meth) acrylate. (Meta) acrylates such as octyl acrylate, lauryl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate A polymer or copolymer containing one or more esters as a monomer is preferably used.

It is preferable that the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meth) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with active energy rays such as ultraviolet rays and electron beams, and has adhesiveness even before irradiation with active energy rays. It is an adhesive composition having a property that it can be brought into close contact with an adherend such as, etc., and can be cured by irradiation with active energy rays to adjust the adhesive force and the like.

The active energy ray-curable pressure-sensitive adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the cross-linking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer, or the like may be contained.

The active energy ray-polymerizable compound is, for example, a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; obtained by reacting two or more kinds of functional group-containing compounds, and at least in the molecule. Examples thereof include (meth) acrylic compounds such as (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having two (meth) acryloyloxy groups.

The pressure-sensitive adhesive composition includes fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, pressure-sensitive adhesives, and fillers (metal powders and other inorganic powders). Etc.), antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and other additives can be included.

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

The thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is, for example, 0.5 μm or more and 100 μm or less, preferably 0.7 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less.

The storage elastic modulus of the pressure-sensitive adhesive layer at 25 ° C. is preferably 0.01 MPa to 1.0 MPa, more preferably 0.02 MPa to 0.1 MPa. The storage elastic modulus is measured, for example, under the following conditions. A plurality of pressure-sensitive adhesive layers are laminated so as to have a thickness of 0.6 mm. A cylinder (height 0.6 mm) having a diameter of 8 mm is punched out from the obtained pressure-sensitive adhesive layer, and this is used as a sample for measuring the storage elastic modulus. According to JIS K7244-6, it can be measured by the torsional shear method using a viscoelasticity measuring device. The frequency can be 1 Hz.

[Other components]
The back plate of the laminated body 100 may be bonded to the laminated body 100 via the second pressure-sensitive adhesive layer. Examples of the back plate include a touch sensor panel, a display element such as an organic EL display element, or a combination thereof.

FIG. 2 shows a schematic cross-sectional view of the laminated body 200 according to another aspect. The laminate 200 includes a front plate 10 and a circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer. The circularly polarizing plate 20 with a double-sided pressure-sensitive adhesive layer has a first pressure-sensitive adhesive layer 30, a linear polarizing plate 40, a bonding layer 50, a retardation layer 60, and a second pressure-sensitive adhesive layer 70 in this order. The linear polarizing plate 40 has a base material 41, an alignment film 42, a polarizer 43, and a protective layer 44 in this order, and the retardation layer 60 includes a λ / 4 layer 61, a bonding layer 62, and the like. It has a positive C layer 63 in this order.

(Lated layer)
The bonding layers 50 and 62 are a pressure-sensitive adhesive layer or an adhesive layer, and can be formed by using a pressure-sensitive adhesive composition or an adhesive composition. The bonded layer may have a single-layer structure or a multi-layer structure, but is preferably a single-layer structure. The pressure-sensitive adhesive composition may be the same as that exemplified in the above description of the pressure-sensitive adhesive layer.

The adhesive composition may be a known adhesive composition, and examples thereof include a water-based adhesive composition such as a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane emulsion adhesive; active energy such as ultraviolet rays. Examples thereof include an active energy ray-curable adhesive composition that is cured by irradiating with a line.

The thicknesses of the bonded layers 50 and 62 are, for example, 0.5 μm or more and 100 μm or less, preferably 0.7 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less.

The laminate 200 can be manufactured by a method including a step of laminating layers constituting the laminate via an adhesive layer or an adhesive layer. When the layers are bonded to each other via the pressure-sensitive adhesive layer or the adhesive layer, one or both of the bonded surfaces should be subjected to a surface activation treatment such as a corona treatment in order to improve the adhesion. Is preferable.

The polarizer 43 can be formed on the base material 41 via the alignment film 42. The polarizer 43 can be formed by applying a polarizing element-forming composition containing a dichroic dye and a polymerizable liquid crystal compound and curing the composition. The composition for forming a polarizer further contains, preferably, a polymerization initiator, a leveling agent, a solvent, a photosensitizer, a polymerization inhibitor, a leveling agent, etc., in addition to the above-mentioned dichroic dye and polymerizable liquid crystal compound. Can include.

The retardation layer 60 can be produced by applying a composition for forming a retardation layer containing a polymerizable liquid crystal compound on a base material and an alignment film, if present, and polymerizing the polymerizable liquid crystal compound. .. The composition for forming a retardation layer further contains a solvent and a polymerization initiator, and may further contain a photosensitizer, a polymerization inhibitor, a leveling agent and the like. The base material and the alignment film may be incorporated into the retardation layer, or may not be separated from the retardation layer and become a component of the laminate.

The coating, drying, and polymerization of the polymerizable liquid crystal compound can be carried out by a conventionally known coating method, drying method, and polymerization method.

The pressure-sensitive adhesive layers 30 and 70 can be prepared as a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet 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, which is then subjected to a release treatment to form a layer of the pressure-sensitive adhesive on a release film. It can be produced by forming it into a sheet shape and laminating another release film on the pressure-sensitive adhesive layer. Each layer can be bonded by a method in which the pressure-sensitive adhesive sheet from which one release film has been peeled off is attached to one layer, then the other release film is peeled off, and the other layer is attached.

<Image display device>
The image 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, a touch panel display device, and an electroluminescence display device. .. Since the image display device of the present embodiment has a bendable laminate, it can be suitably used for a flexible display, and particularly preferably for an organic EL display device.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "part" in the example are mass% and parts by mass.

[Layer thickness]
The measurement was performed using a contact type film thickness measuring device (“MS-5C” manufactured by Nikon Corporation). However, the polarizer layer, the retardation layer and the alignment film were measured using a laser microscope (LEXT, manufactured by Olympus Corporation).

[Method for measuring tensile elastic modulus]
The tensile elastic modulus was measured using a UTM (Universal Testing Machine, Autograph AG-X, Shimadzu Corporation) in accordance with JIS K7161. The stretching conditions were a speed of 4 mm / min, a width of 10 mm, and a gauge point distance of 50 mm in a moisture-resistant heat-resistant environment (temperature 60 ° C., humidity 90% RH).

[Swell evaluation]
A polyethylene terephthalate (PET) film was attached to the laminates obtained in each Example and Comparative Example via an adhesive layer provided in the laminate to obtain a test piece. The PET film imitated an image display element, and its thickness was 100 μm. The test piece was laser-cut and subjected to a moisture-resistant heat bending test under the following conditions, and then the swell of the bent portion was measured using an interference microscope. The swell is installed in the interference microscope so that the front plate of the laminated body is on the upper side, and among the irregularities observed on the front plate side surface of the bent portion of the laminated body by the interference microscope, the highest point and the lowest point are It was calculated as the average value of the height difference (n = 6).
(Moisture resistance heat bending test)
The laminate was allowed to stand for 10 days in an atmosphere of a temperature of 60 ° C. and a relative humidity of 90% RH in a state of being bent with a radius of curvature of 1 mm (1R) with the front plate side inside.

[Visibility]
The laminated body after the swell evaluation was made into a flat state by opening the bent state. This laminated body was installed under the fluorescent lamp so that the front plate side was facing upward, and the image of the fluorescent lamp reflected on the surface of the laminated body was observed. In the bent portion, the case where the distortion was not visually recognized in the image of the fluorescent lamp was marked with ◯, and the case where the distortion was visually recognized in the image of the fluorescent lamp was marked with x.

[Front plate 1]
(Polyamide-imide film)
In a nitrogen gas atmosphere, 14.67 g (45.8 mmol) of 2,2'-bis (trifluoromethyl) benzidine (TFMB) and a water content of 200 ppm were prepared in a 1 L separable flask equipped with a stirring blade. -233.3 g of dimethylacetamide (DMAc) was added, and TFMB was dissolved in DMAc with stirring at room temperature. Next, 4.283 g (13.8 mmol) of 4,4'-oxydiphthalic dianhydride (OPDA) was added to the flask, and the mixture was stirred at room temperature for 16.5 hours. Then, 1.359 g (4.61 mmol) of 4,4'-oxybis (benzoyl chloride) (OBBC) and 5.609 g (27.6 mmol) of terephthaloyl chloride (TPC) were added to the flask, and the mixture was stirred at room temperature for 1 hour. .. Next, 4.937 g (48.35 mmol) of acetic anhydride and 1.501 g (16.12 mmol) of 4-picoline were added to the flask, and the mixture was stirred at room temperature for 30 minutes, heated to 70 ° C. using an oil bath, and further. The mixture was stirred for 3 hours to obtain a reaction solution.
After cooling the obtained reaction solution to room temperature, 360 g of methanol and 170 g of ion-exchanged water were added to obtain a precipitate of polyamide-imide. It was immersed in methanol for 12 hours, collected by filtration and washed with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C. to obtain a polyamide-imide (PAI) resin having a thickness of 50 μm.

(Composition for forming HC layer 1)
The composition 1 for forming an HC layer contains 30 parts by mass of a polyfunctional acrylate (Miramer M340, manufactured by Miwon Specialy Chemical), 50 parts by mass of a propylene glycol monomethyl ether dispersion (12 nm, solid content 40%) of a nanosilica sol, and ethyl acetate. It contains 17 parts by mass, 2.7 parts by mass of a photopolymerization initiator (Irgacure-184, manufactured by Ciba Corporation), and 0.3 parts by mass of a fluorine-based additive (KY1203, manufactured by Shin-Etsu Chemical Industry Co., Ltd.).

(Making the front plate 1)
The above composition for forming an HC layer is applied to one surface of a polyamide-imide film, the obtained coating film is dried at a temperature of 80 ° C. for 5 minutes, and a UV irradiation device (SPOT CURE SP-7, manufactured by Ushio Denki Co., Ltd.) ) Was irradiated with UV light having an exposure amount of 500 mJ / cm ² (365 nm standard) to form the HC layer 1. The coating was applied so that the thickness after curing was 10.0 μm. As described above, a front plate 1 having a polyamide-imide film structure having an HC layer of 1/50 μm was obtained.

[Front plate 2]
In the preparation of the polyamide-imide film of the front plate 1, 6.140 g of 4,4'-(hexafluoroisopropylidene) diphthalic acid dianhydride (6FDA) was used instead of 4.283 g of OPDA to 14.67 g (45.8 mmol) of TFMB. Thickness similar to the preparation of the polyamide-imide film of the front plate 1 except that 8.809 g (27.5 mmol) of TFMB and 3.889 g (18.3 mmol) of 2,2'-dimethylbenzidine (MB) were used instead. A 40 μm polyamide-imide resin was obtained.

[Front plate 3]
A cycloolefin (COP) film (thickness 40 μm, manufactured by Nippon Zeon Corporation) was prepared.

[Front plate 4]
A triacetyl cellulose (TAC) film (thickness 40 μm) was prepared.

[Preparation of composition for forming a polarizer layer]
(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound is a polymerizable liquid crystal compound represented by the formula (1-6) [hereinafter, also referred to as compound (1-6)] and a polymerizable liquid crystal compound represented by the formula (1-7) [hereinafter, Also referred to as compound (1-7)].

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

(Dichroic pigment)
As the dichroic dye, the azo dye described in Examples of Japanese Patent Application Laid-Open No. 2013-101328 represented by the following formulas (2-1a), (2-1b) and (2-3a) was used.

(Preparation of composition for forming a polarizer layer)
The composition for forming the polarizer layer has 75 parts by mass of the compound (1-6), 25 parts by mass of the compound (1-7), and the above formulas (2-1a), (2-1b), as bicolor dyes. 2.5 parts by mass of each of the azo dyes represented by 2-3a), 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one as a polymerization initiator (Irgacure 369, manufactured by BASF Japan, Ltd.) ) 6 parts by mass and 1.2 parts by mass of a polyacrylate compound (BYK-361N, manufactured by BYK-Chemie) as a leveling agent are mixed with 400 parts by mass of toluene as a solvent, and the obtained mixture is 1 at 80 ° C. Prepared by stirring for hours.

[Adhesive layer 1]
A pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 1 was prepared at the ratio of each component shown in Table 1 below. This pressure-sensitive adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (thickness 38 μm) using an applicator so that the thickness after drying was 25 μm. The coating layer was dried at 100 ° C. for 1 minute to obtain a film having the pressure-sensitive adhesive layer 1. Then, another polyethylene terephthalate film (thickness 38 μm) that had been released from the mold was attached onto the pressure-sensitive adhesive layer 1. Then, it was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 50% RH.
The symbols in the column of monomers in Table 1 have the following meanings.
BA: Butyl acrylate MMA: Methyl acrylate EHA: 2-Ethylhexyl acrylate AA: Acrylic acid The following cross-linking agents and silane coupling agents were used in Table 1.
Crosslinking agent: Coronate L (manufactured by Tosoh Corporation)
Silane coupling agent: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Adhesive layer 2]
A film having the pressure-sensitive adhesive layer 2 was obtained in the same manner as the pressure-sensitive adhesive layer 1 except that the thickness after drying was set to 5 μm.

[Adhesive layer 3]
A pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 was prepared at the ratio of each component shown in Table 1 below. This pressure-sensitive adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (thickness 38 μm) using an applicator so that the thickness after drying was 5 μm. The coating layer was dried at 100 ° C. for 1 minute to obtain a film having the pressure-sensitive adhesive layer 3. Then, another polyethylene terephthalate film (thickness 38 μm) that had been released from the mold was attached 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.

[Base material 1]
A triacetyl cellulose (TAC) film (thickness 25 μm) was prepared.

[Base material 2]
(Composition for forming HC layer 2)
Dendrimer acrylate (Miramer SP1106, Miwon Speciality Chemical) having 18-functional acryloyloxy group (sometimes referred to as acrylic group) 2.0 parts by mass, urethane acrylate (Miramer PU-620D, Miwon Speciality) having 6-functional acrylic group Chemical) 10.0 parts by mass, acrylate monomer having a trifunctional acrylic group (M340, Miwon Speciality Chemical) 8 parts by mass, photopolymerization initiator (Irgacure (registered trademark) 184, BASF) 2 parts by mass, And 0.1 part by mass of the leveling agent (BYK-UV3530, Big Chemie Japan Co., Ltd.) was dissolved in 70 parts by mass of methyl ethyl ketone (MEK) and mixed by stirring to obtain a composition 2 for forming a hard coat layer.

(Preparation of base material 2)
The HC layer forming composition 2 is applied to one surface of a cycloolefin (COP) film (thickness 13 μm), the obtained coating film is dried at a temperature of 80 ° C. for 5 minutes, and a UV irradiation device (SPOT CURE SP) is applied. The HC layer 2 was formed by irradiating UV light with ^{an exposure amount of 500 mJ / cm 2} (365 nm standard) using -7 (manufactured by Ushio Denki Co., Ltd.). The coating was applied so that the thickness after curing was 2 μm. As described above, the base material 2 was obtained.

[Λ / 4 layer]
A composition for forming a horizontal alignment film is obtained by mixing 5 parts (weight average molecular weight: 30,000) of a photooriented material having the following structure and 95 parts of cyclopentanone, and stirring the obtained mixture at 80 ° C. for 1 hour. I got something.

1.0 part of the leveling agent (F-556; manufactured by DIC Corporation) was added to 100 parts of the mixture of the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B shown below at a mass ratio of 90:10. And 6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (“Irgacure 369 (Irg369)”, manufactured by BASF Japan KK), which is a polymerization initiator, was added.

Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%, and the mixture was stirred at 80 ° C. for 1 hour to obtain a retardation layer forming composition (1).

The polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. Further, the polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. The molecular structure of each is shown below.

(Polymerizable liquid crystal compound A)

(Polymerizable liquid crystal compound B)

A base film made of a cycloolefin polymer (COP) film (ZF-14, manufactured by Nippon Zeon Corporation, thickness 23 μm) was produced using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Works Ltd.) at an output of 0.3 kW. Corona treatment was performed once under the condition of a treatment speed of 3 m / min. The composition for forming a horizontal alignment film was applied to the surface of the corona-treated substrate by a bar coater. The coating film was dried at 80 ° C. for 1 minute, and polarized UV exposure was performed using a polarized UV irradiator (SPOT CURE SP-7; manufactured by Ushio, Inc.) with ^{an integrated light intensity of 100 mJ / cm 2.} The thickness of the obtained horizontal alignment film was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 100 nm.

Subsequently, the composition for forming a retardation layer (1) was passed through a PTFE membrane filter (manufactured by Advantech Toyo Co., Ltd., product number; T300A025A) having a pore size of 0.2 μm in an environment of room temperature of 25 ° C. and humidity of 30% RH. It was applied using a bar coater on a base film with an alignment film kept at 25 ° C. After the coating film is dried at 120 ° C. for 1 minute, it is irradiated with ultraviolet rays using a high-pressure mercury lamp (UNICURE VB-15201BY-A, manufactured by Ushio Denki Co., Ltd.) (in a nitrogen atmosphere, wavelength: 365 nm, integrated light intensity at wavelength 365 nm). : 1000 mJ / cm ² ) to produce an optical film. The thickness of the obtained coating film was measured with a laser microscope (Lext, manufactured by Olympus Corporation) and found to be 2 μm.

In this way, a laminated body (phase difference layer 1) in which a layer in which the polymerizable liquid crystal compound was cured (λ / 4 layer), a horizontal alignment film, and a base film were laminated in this order was obtained. The retardation layer 1 showed anti-wavelength dispersibility.

[Positive C layer]
As a composition for forming a vertically oriented film, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis (2-vinyloxyethyl) ether are mixed in a ratio of 1: 1: 4: 5. A mixture was mixed and LUCIRIN TPO was added as a polymerization initiator at a ratio of 4%.

The retardation layer forming composition (2) was prepared by preparing a photopolymerizable nematic liquid crystal compound (manufactured by Merck & Co., Inc., RMM28B) and a solvent so that the solid content was 1 to 1.5 g. As the solvent, a mixed solvent was used in which methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) were mixed at a mass ratio (MEK: MIBK: CHN) of 35:30:35. ..

A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a base film. A composition for forming a vertical alignment film was applied to one side of the base film so as to have a film thickness of 3 μm, and ^{an ultraviolet ray of 200 mJ / cm 2} was irradiated to prepare a vertical alignment film.

The composition for forming a retardation layer (2) was coated on the vertically oriented layer by die coating. The coating amount was 4 to 5 g (wet). The coating film was dried with a drying temperature of 75 ° C. and a drying time of 120 seconds. Then, the coating film was irradiated with ultraviolet rays (UV) to polymerize the polymerizable liquid crystal compound. The thickness of the obtained coating film was measured with a laser microscope (Lext, manufactured by Olympus Corporation) and found to be 1 μm.

In this way, a laminated body (phase difference layer 2) in which a layer in which the polymerizable liquid crystal compound was cured (positive C layer), a vertically oriented film, and a base film were laminated in this order was obtained. In the retardation layer 2, the total thickness of the layer obtained by curing the polymerizable liquid crystal compound and the alignment film was 4 μm.

[Phase difference layer]
The above-mentioned retardation layer 1 and retardation layer 2 are bonded together via an adhesive layer 3 so that the surface opposite to the surface on the base film side is the bonding surface, and the base film / horizontal A retardation layer having the composition of an alignment film / (λ / 4 layer) / adhesive layer 3 / positive C layer / vertical alignment film / base film was obtained.

<Example 1>
First, the base material 1 was prepared. The composition for forming an alignment film was applied onto the base material 1 by the bar coating method. The coating was dried at 80 ° C. for 1 minute. Next, using the above UV irradiation device and wire grid, the coating film was irradiated with polarized UV to impart orientation performance to the coating film. The exposure amount was 100 mJ / cm ² (based on 365 nm). As the wire grid, UIS-27132 ## (manufactured by Ushio, Inc.) was used. In this way, the alignment film was formed. The thickness of the alignment film was 100 nm.

The above-mentioned composition for forming a polarizer was applied onto the formed alignment film by a bar coating method. The coating film was dried by heating at 100 ° C. for 2 minutes and then cooled to room temperature. A polarizer was formed by irradiating the coating film with ultraviolet rays at an integrated light intensity of 1200 mJ / cm ^{2 (365 nm standard) using the above UV irradiation device.} The thickness of the obtained polarizer was 3 μm. A composition containing polyvinyl alcohol and water was applied onto the polarizer so that the thickness after drying was 0.5 μm, and dried at a temperature of 80 ° C. for 3 minutes to form a protective layer. In this way, a linear polarizing plate having a base material 1 / alignment film / polarizer / protective layer configuration was produced.

After corona treatment is applied to the surface of the front plate 1 opposite to the HC layer 1 and the surface of the pressure-sensitive adhesive layer 1 exposed by peeling off one polyethylene terephthalate film of the film provided with the pressure-sensitive adhesive layer 1. Both were pasted together.

Next, the surface of the pressure-sensitive adhesive layer 1 exposed by peeling the other polyethylene terephthalate film from the pressure-sensitive adhesive layer 1 and the surface of the linear polarizing plate on the base material 1 side are subjected to corona treatment, and then the two are bonded together. It was. Then, the surface of the linear polarizing plate on the protective layer side and the surface of the adhesive layer 3 exposed by peeling off one polyethylene terephthalate film of the film provided with the adhesive layer 3 are subjected to corona treatment, and then both are subjected to corona treatment. I pasted them together. Next, the other polyethylene terephthalate film was peeled off from the pressure-sensitive adhesive layer 3 to expose the pressure-sensitive adhesive layer 3. In this way, a laminate having the composition of front plate 1 / pressure-sensitive adhesive layer 1 / base material 1 / alignment film / polarizer / protective layer / pressure-sensitive adhesive layer 3 was obtained.

The base film used for forming the retardation layer 1 was peeled off from the retardation layer described above. The exposed λ / 4 layer and the pressure-sensitive adhesive layer 3 were bonded together. The angle formed by the absorption axis of the polarizer and the slow axis of the λ / 4 layer was 45 °. Next, the base film used for forming the retardation layer 2 was peeled off to expose the positive C layer. Then, a film provided with another pressure-sensitive adhesive layer 1 was prepared, and one of the polyethylene terephthalate films was peeled off to expose the surface of the pressure-sensitive adhesive layer 1. After corona treatment was applied to the exposed surface of the positive C layer and the surface of the pressure-sensitive adhesive layer 1, both were bonded together. Then, the other polyethylene terephthalate film was peeled off from the pressure-sensitive adhesive layer 1. In this way, the front plate 1 / adhesive layer 1 / base material 1 / alignment film / polarizer / protective layer / adhesive layer 3 / (λ / 4 layer) / adhesive layer 3 / positive C layer / adhesive A laminate of Example 1 having the structure of layer 1 was obtained. The results are shown in Table 2. In Example 1, the circularly polarizing plate with the double-sided pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer 1 / base material 1 / alignment film / polarizer / protective layer / pressure-sensitive adhesive layer 3 / (λ / 4 layer) / pressure-sensitive adhesive layer 3 /. It is composed of a positive C layer / an adhesive layer 1.

<Example 2>
A laminate of Example 2 was obtained in the same manner as in Example 1 except that the front plate 2 was used instead of the front plate 1 in Example 1. The results are shown in Table 2.

<Example 3>
A laminate of Example 3 was obtained in the same manner as in Example 1 except that the front plate 3 was used instead of the front plate 1 in Example 1. The results are shown in Table 2.

<Example 4>
In Example 1, instead of preparing the base material 1 and applying the alignment film forming composition on the base material 1, the base material 2 is prepared and the alignment film is formed on the HC layer 2 of the base material 2. Lamination of Example 4 in the same manner as in Example 1 except that the composition for use was applied and the film provided with the pressure-sensitive adhesive layer 2 was used instead of the film provided with the pressure-sensitive adhesive layer 1. I got a body. The results are shown in Table 2.

<Comparative example 1>
A laminate of Comparative Example 1 was produced in the same manner as in Example 4 except that the front plate 4 was used instead of the front plate 1 in Example 4. The results are shown in Table 2.

10 Front plate, 20 Circular polarizing plate with double-sided adhesive layer, 30 First adhesive layer, 40 Linear polarizing plate, 41 Base material, 42 Alignment film, 43 Polarizer, 44 Protective layer, 50 Laminated layer, 60 Phase difference Layers, 61 λ / 4 layers, 62 laminating layers, 63 positive C layers, 70 second adhesive layers, 100,200 laminates.

Claims (7)

A front plate and a circularly polarizing plate with a double-sided adhesive layer are provided, the thickness of the front plate is a [μm], the thickness of the circularly polarizing plate with a double-sided adhesive layer is b [μm], and the thickness of the front plate is b [μm]. When the tensile elastic modulus at a temperature of 60 ° C. and a relative humidity of 90% RH is c [MPa], the following formula (1) is satisfied.
[(B / a) × c] ≧ 2200 MPa (1)
The front plate is a layer constituting the outermost surface of the display device.
The thickness of the front plate is 30 μm or more and 70 μm or less.
Tensile modulus at temperatures 60 ° C. and a relative humidity of 90% RH of the front plate state, and are more 6000MPa less 3103.4 MPa,
A laminate that can be bent in the direction with the front plate inside. The laminate according to claim 1, wherein the a and c satisfy the following formula (2).
a / c ≤ 0.03 μm / MPa (2) The laminate according to claim 1 or 2, wherein the front plate has a hard coat layer. The circular polarizing plate with a double-sided pressure-sensitive adhesive layer includes a first pressure-sensitive adhesive layer, a linear polarizing plate, a retardation layer, and a second pressure-sensitive adhesive layer in this order, according to any one of claims 1 to 3. The laminate described. The laminate according to claim 4, wherein the linear polarizing plate includes a thermoplastic resin film having a hard coat layer on at least one surface. The laminate according to any one of claims 1 to 5, wherein the thickness of the circularly polarizing plate with a double-sided pressure-sensitive adhesive layer is 20 μm or more and 100 μm or less. An image display device comprising the laminate according to any one of claims 1 to 6.

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