KR102220433B1 - Flexible laminate and image display device having the same - Google Patents

Abstract

[Problem] Provided are a flexible laminate having impact resistance and excellent flexibility and an image display device including the same.
[Solution means] The flexible laminate includes a front plate, a first adhesive layer, a circularly polarizing plate, a second adhesive layer, and a touch sensor panel in this order. The thickness of the front plate is a[㎛], the thickness of the first adhesive layer is b[㎛], the thickness of the circularly polarizing plate is c[㎛], the thickness of the second adhesive layer is d[㎛], and the thickness of the touch sensor panel When e[µm], the tensile modulus of the front plate at a temperature of 23°C and a relative humidity of 55% is Ea[GPa], the following formula (i):
{Ea×(a+b)}/(a+b+c+d+e)≥1.5 (i)
Satisfy the relationship.

Description

A flexible laminate and an image display device provided with it TECHNICAL FIELD

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

In the field of various image display devices such as a liquid crystal display device and an organic electroluminescent (EL) display device, there is known a flexible display in which a display panel can be folded using a flexible substrate (for example, Patent Document 1 , 2).

Patent Document 1: Korean Patent Application Publication No. 10-2016-0053788 Patent Document 2: Korean Laid-Open Patent Publication No. 10-2017-0093610

A substrate having flexibility is excellent in flexible properties, but there is a tendency for impact resistance to be inferior when compared to glass that has been used in conventional image display devices. On the other hand, if an attempt is made to improve the impact resistance of a flexible substrate, there is a tendency for the flexible property to decrease.

An object of the present invention is to provide a flexible laminate having impact resistance and excellent flexibility and an image display device including the same.

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

[1] A flexible laminate comprising a front plate, a first adhesive layer, a circularly polarizing plate, a second adhesive layer, and a touch sensor panel in this order,

The thickness of the front plate is a[㎛], the thickness of the first adhesive layer is b[㎛], the thickness of the circularly polarizing plate is c[㎛], the thickness of the second adhesive layer is d[㎛] and the touch When the thickness of the sensor panel is e[µm], and the tensile modulus at a temperature of 23°C and a relative humidity of 55% of the front plate is Ea[GPa], the following equation (i):

{Ea×(a+b)}/(a+b+c+d+e)≥1.5 (i)

A flexible laminate that satisfies the relationship of.

[2] The tensile modulus Ea[GPa] of the front plate, the thickness b of the first adhesive layer, and the thickness d of the second adhesive layer are represented by the following formula (ii):

b/(Ea×d)≥0.3 (ii)

The flexible laminate according to [1] that satisfies the relationship of.

[3] The stiffness of the front plate at a temperature of 23°C and a relative humidity of 55% is 0.09 GPa·mm or more and 0.7 GPa·mm or less,

The stiffness of the circularly polarizing plate at a temperature of 23° C. and a relative humidity of 55% is 40 MPa·mm or more and 400 MPa·mm or less,

The flexible laminate according to [1] or [2], wherein the touch sensor panel has a rigidity of 15 MPa·mm or more and 700 MPa·mm or less at a temperature of 23°C and a relative humidity of 55%.

[4] The storage modulus of the first pressure-sensitive adhesive layer at a temperature of 25°C and a relative humidity of 50% is 0.01 MPa or more and 0.15 MPa or less,

The flexible laminate according to any one of [1] to [3], wherein the storage modulus of the second pressure-sensitive adhesive layer at a temperature of 25°C and a relative humidity of 50% is 0.01 MPa or more and 0.15 MPa or less.

[5] The total thickness t[㎛] of the thickness a of the front plate, the thickness b of the first adhesive layer, the thickness c of the circularly polarizing plate, the thickness d of the second adhesive layer, and the thickness e of the touch sensor panel , The following formula (iii):

t=a+b+c+d+e (iii)

When represented by t, the flexible laminate according to any one of [1] to [4], wherein t is 250 µm or less.

[6] The flexible laminate according to any one of [1] to [5], wherein the front plate is a resin film or a resin film with a hard coat layer having a hard coat layer on at least one surface of the resin film.

[7] The flexible laminate according to any one of [1] to [6], wherein the flexible laminate has a limit of bending times of 50,000 or more in a flexural test in which the front plate side is inwardly bent.

[8] The flexible laminate according to any one of [1] to [7], wherein the flexible laminate has a limit of bending times of 50,000 or more in a flexural test in which the front plate side is bent outside.

[9] An image display device comprising the flexible laminate according to any one of [1] to [8], and wherein the front plate is disposed on the entire surface.

Advantageous Effects of Invention According to the present invention, it is possible to provide a flexible laminate having impact resistance and excellent flexibility and an image display device including the same.

1 is a schematic cross-sectional view schematically showing an example of a flexible laminate of the present invention.
2 is a schematic cross-sectional view schematically showing an example of the image display device of the present 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 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.

(Flexible laminate)

1 is a schematic cross-sectional view schematically showing an example of a flexible laminate of the present embodiment. The flexible laminate 100 is a front plate 10, a first adhesive layer 20, a circularly polarizing plate 30, a second adhesive layer 40, and a touch sensor panel (hereinafter, referred to as "TS panel" Yes.) Includes (50). As shown in FIG. 1, the flexible laminate 100 is a front plate 10, a first adhesive layer 20, a circular polarizing plate 30, a second adhesive layer 40, and a TS panel from the viewer side. (50) are stacked in this order.

The flexible laminate 100 has flexibility, and accordingly, it can be applied to an image display device (flexible display) capable of folding or winding. The flexible laminate 100 of the present embodiment is particularly excellent in flexibility (hereinafter, referred to as "flexibility (in)" in some cases) to be bent with the front plate 10 inward. Specifically, the flexible laminate 100 has a bendability of 50,000 or more, which is the number of bendings in which cracks or lifting of the pressure-sensitive adhesive layer occurred in the bent region in the flexibility (in) test in the examples to be described later. It may have, and the number of limit bending is preferably 100,000 or more, and more preferably 200,000 or more.

In addition, in one embodiment of the flexible laminate 100, in addition to the above-described flexibility (in), the flexibility (hereinafter referred to as ``flexibility (out)'') to be bent with the front plate 10 side outside. .) can also be said to be excellent. Specifically, in the flexural (out) test in the examples to be described later, the flexible laminate 100 preferably has a bendability of 50,000 or more, and more preferably, 100,000 or more. And more preferably more than 200,000 times.

The flexible laminate 100 can constitute an image display device as described above, and can be particularly suitably used for a flexible display capable of folding or winding. Further, since the flexible laminate 100 includes the circularly polarizing plate 30, it can also be used as an antireflection film in an organic electroluminescent (EL) display device, for example.

In the flexible laminate 100, the thickness of the front plate 10 is set to a [µm], the thickness of the first adhesive layer 20 is set to b [µm], the thickness of the circularly polarizing plate 30 is set to c [µm], 2 Set the thickness of the pressure-sensitive adhesive layer 40 to d[µm] and the thickness of the TS panel 50 as e[µm], and the tensile modulus of the front plate at 23°C and 55% relative humidity as Ea[GPa]. When, the following formula (i):

{Ea×(a+b)}/(a+b+c+d+e)≥1.5 (i)

Satisfy the relationship. In the following, the total thickness t [µm] of the front plate 10, the first adhesive layer 20, the circularly polarizing plate 30, the second adhesive layer 40, and the TS panel 50 is given by the following formula (iii). :

t=a+b+c+d+e (iii)

It may be indicated as.

{Ea×(a+b)}/t(b+d)/t in the above formula (i) (where t is represented by the above formula (iii)) is preferably 1.65 or more, and more preferably 1.70 or more. It is preferable, and may be 2.00 or more, 2.50 or more, usually 6.00 or less, 5.50 or less, 5.00 or less, and 4.50 or less.

The flexible laminate 100 is installed in the image display device so that the front plate 10 side becomes the front side (viewer side). Therefore, from the viewpoint of the impact resistance of the flexible laminate 100, it is preferable that the thickness a of the front plate 10 and the thickness b of the first adhesive layer 20 positioned on the front side of the image display device are large. In addition, from the viewpoint of the impact resistance of the flexible laminate 100, it is preferable that the tensile modulus Ea of the front plate 10 is also larger. On the other hand, from the viewpoint of the flexibility of the flexible laminate 100, it is preferable that the total thickness t represented by the above formula (iii) is smaller. Therefore, in order to achieve both impact resistance and flexibility in the flexible laminate 100, in {Ea×(a+b)}/t in the above formula (i), it is considered that the denominator should be small and the numerator should be increased. .

When the flexible laminate 100 satisfies the relationship of the above formula (i), good impact resistance is obtained, and in particular, a flexible laminate having excellent flexibility (in) to be bent with the front plate 10 inwardly You can do it with (100).

Although the total thickness t represented by the above formula (iii) is not particularly limited, in recent years, image display devices have undergone thinning or weight reduction, and members used in image display devices tend to be required to be thinner or lighter. It is also required to reduce the thickness of the sieve 100. Therefore, the flexible laminate 100 is also required to be thinner, and its thickness is preferably 250 µm or less, more preferably 220 µm or less, 200 µm or less, or 180 µm or less, It may be 150 µm or less, usually 40 µm or more, and 70 µm or more.

The flexible laminate 100 is the following formula (iv):

(b+d)/t≥0.5 (iv)

It is desirable to satisfy. (B+d)/t in the above formula (iv) is more preferably 0.5 or more, more preferably 0.6 or more, may be 0.65 or more, usually 0.9 or less, or 0.8 or less. When the flexible laminate 100 satisfies the relationship of formula (iv), in the flexible laminate 100, the first pressure-sensitive adhesive layer 20 and the second pressure-sensitive adhesive layer 40 can be formed with a predetermined thickness or more. . Thereby, while securing the flexibility of the flexible laminated body 100, the shock absorption property of the flexible laminated body 100 can be improved, and the impact resistance can be improved.

In the flexible laminate 100, the tensile modulus Ea of the front plate 10, the thickness b of the first pressure-sensitive adhesive layer 20, and the thickness d of the second pressure-sensitive adhesive layer 40 are the following formula (ii):

b/(Ea×d)≥0.3 (ii)

It is desirable to satisfy the relationship. B/(Ea×d) in the above formula (ii) is preferably 0.40 or more, more preferably 0.50 or more, and usually 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less, and may be 1.8 or less. .

The flexible laminate 100 has flexibility. From the viewpoint of imparting good flexibility (in) and flexibility (out) to the flexible laminate 100, the thickness d of the second pressure-sensitive adhesive layer 40 is preferably small (that is, b/d is large). Further, when the shear stress at the time of bending the flexible laminate 100 becomes small, it becomes easy to bend the flexible laminate 100. Therefore, it is preferable that the tensile modulus Ea of the front plate 10 be small (that is, 1/Ea is large). Therefore, in order to have good flexibility (in) and flexibility (out) in the flexible laminate 100, in b/(Ea×d) of the above formula (ii), it is suggested that the denominator should be small and the numerator should be increased. I think.

When the flexible laminate 100 satisfies the relationship of the above formula (ii), in particular, in addition to the above-described flexibility (in), it is possible to have excellent bendability (out) to be bent with the front plate 10 side to the outside. have.

In the flexible laminate 100, the thickness b of the first pressure-sensitive adhesive layer 20 and the thickness d of the second pressure-sensitive adhesive layer 40 are the following formula (v):

0.5≤b/d≤7 (v)

It is desirable to satisfy the relationship. Since the thickness b of the first pressure-sensitive adhesive layer 20 is preferably larger than the thickness d of the second pressure-sensitive adhesive layer 40, b/d in the above formula (v) is more preferably 1 or more, and even more preferably 1.5 or more. And 2 or more may be sufficient, and 3 or more may be sufficient. In addition, b/d in the formula (v) is preferably 6 or less, more preferably 5.5 or less, and may be 5 or less. Since the thickness b of the first pressure-sensitive adhesive layer 20 and the thickness d of the second pressure-sensitive adhesive layer 40 are in the relationship of the above formula (v), in particular, the flexibility to bend with the front plate 10 inside An excellent flexible laminate 100 can be obtained.

The shape of the flexible laminate 100 in the plane direction is not particularly limited, but it is preferably a rectangular shape, and more preferably a rectangular shape. When the flexible laminate 100 has a rectangular shape, the length of the long side is preferably 50 mm to 300 mm, and may be 100 mm to 280 mm, and the length of the short side is preferably 30 mm to 250 mm, for example, 60 It may be mm to 220 mm. The flexible laminate 100 may be a rounded rectangular shape in which at least one of the corners of the rectangular shape is subjected to R processing, or may be a rectangular shape having a notch on at least one side. Further, the flexible laminate 100 may be provided with a hole portion penetrating in the lamination direction.

(Front panel)

The front plate 10 can function as a layer for protecting display elements of an image display device and the like, and is a plate-like body capable of transmitting light, and the plate-like body is preferably made of glass or resin. The front plate 10 may be disposed on the most surface of the image display device. It is preferable that the front plate 10 is a resin film or a resin film with a hard coat layer in which hardness is further improved by forming a hard coat layer on at least one surface of the resin film. Further, the front plate 10 may have a blue light cutting function, a viewing angle adjustment function, or the like.

The resin film constituting the front plate 10 is not limited as long as it is a resin film capable of transmitting light. For example, triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, polystyrene, polyamide, polyetherimide, poly(meth)acrylic, polyimide, Polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl (meth ) Films formed of polymers such as acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers may be used alone or in combination of two or more. When the image display device 300 is a flexible display, a resin film formed of a polymer such as polyimide, polyamide, and polyamideimide, which can be configured to have excellent flexibility, high strength and high transparency, is suitably used. Is used.

The resin film with a hard coat layer constituting the front plate 10 may have a hard coat layer on one side of the resin film, or may have a hard coat layer on both sides of the resin film. In the case of having hard coat layers on both sides of the resin film, the composition and thickness of each hard coat layer may be the same or different from each other. A resin film with a hard coat layer can improve hardness and a scratch property as compared with a resin film which does not have a hard coat layer.

The hard coat layer of the resin film with a hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth)acrylic resins such as monofunctional (meth)acrylic resins, polyfunctional (meth)acrylic resins, and polyfunctional (meth)acrylic resins having a dendrimer structure; Silicone resin; Polyester resin; Urethane resin; Amide resin; Epoxy resin, etc. are mentioned. 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 10 preferably has a stiffness of 0.090 GPa·mm or more at a temperature of 23°C and a relative humidity of 55%, more preferably 0.12 GPa·mm or more, even more preferably 0.2 GPa·mm or more, and 0.25 It is even more preferable that it is GPa·mm or more, and it is preferable that it is 0.7 GPa·mm or less, and may be 0.6 GPa·mm or less, and 0.5 GPa·mm or less may be sufficient. When the rigidity of the front plate 10 decreases, the flexibility of the flexible laminate 100 improves, while the impact resistance tends to decrease. When the rigidity of the front plate 10 increases, the flexible laminate 100 While the impact resistance is improved, the flexibility tends to decrease. In addition, when the rigidity of the front plate 10 is in the above range, the flexible laminate 100 satisfies the above formula (i) or the relationship of the above formulas (i) and (ii), A flexible laminate 100 having impact properties and excellent flexibility can be obtained suitably.

The rigidity of the front plate 10 is the product of the tensile elastic modulus Ea[GPa] and the thickness [mm] of the entire front plate 10 at 23°C and 55% relative humidity (Ea[ It can be calculated by GPa]×a[µm]×10 ^{−3 ).} The thickness a of the front plate 10 may be, for example, 30 µm or more and 200 µm or less, preferably 50 µm or more and 150 µm or less, more preferably 50 µm or more and 100 µm or less, and 90 µm or less. The tensile modulus Ea of the front plate 10 is, for example, preferably 1 GPa or more, more preferably 2 GPa or more, more preferably 3 GPa or more, further preferably 30 GPa or less, and more preferably 20 GPa or less. And more preferably 10 GPa or less.

(First adhesive layer)

The first pressure-sensitive adhesive layer 20 is a layer for bonding the front plate 10 and the circularly polarizing plate 30 to each other, and can be formed using an adhesive composition. The thickness b of the first pressure-sensitive adhesive layer 20 is not particularly limited as long as it can satisfy the relationship of the above-described formulas (i) and (ii), but is preferably 5 µm or more, more preferably 7 µm or more, and 10 It is more preferable that it is at least 20 µm, and may be at least 30 µm, and is usually 200 µm or less, preferably 100 µm or less, and more preferably 80 µm or less.

The first pressure-sensitive adhesive layer 20 preferably has a storage modulus Gb of 0.005 MPa or more, 0.007 MPa or more, 0.01 MPa or more, and 0.2 MPa or less at a temperature of 25°C and a relative humidity of 50%. And 0.17 MPa or less may be sufficient, and 0.15 MPa or less may be sufficient.

When the storage elastic modulus Gb of the first adhesive layer 20 decreases, the impact resistance of the flexible laminate 100 tends to decrease, and when the storage elastic modulus Gb of the first adhesive layer 20 increases, the flexible laminate 100 ) Tends to decrease. In addition, when the storage elastic modulus Gb of the first pressure-sensitive adhesive layer 20 is in the above-described range, the flexible laminate 100 has the above formula (i) or the relationship of the formulas (i) and (ii). By satisfaction, it is possible to suitably obtain a flexible laminate 100 having impact resistance and excellent flexibility.

The first pressure-sensitive adhesive layer 20 can 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 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 (meth)acrylic acid such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. A polymer or copolymer containing one or two or more esters as a monomer is suitably used. It is preferable to copolymerize a polar monomer to the base polymer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, and glycidyl Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, and an epoxy group such as (meth)acrylate are mentioned.

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 metal carboxylate salt between a carboxyl group; As a polyamine compound, what forms an amide bond between a carboxyl group; A polyepoxy compound or a polyol that forms an ester bond between a carboxyl group; As a polyisocyanate compound, what forms an amide bond between a carboxyl group is illustrated. Among them, polyisocyanate compounds are preferable.

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 to adjust adhesion. It is preferable that the 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. In addition, a photoinitiator, a photosensitizer, etc. may be contained as needed.

The pressure-sensitive adhesive composition includes fine particles for imparting 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, Additives such as an ultraviolet absorber, a dye, a pigment, a colorant, an antifoaming agent, a corrosion inhibitor, and a photopolymerization initiator may be included.

The first pressure-sensitive adhesive layer 20 can be formed by applying a diluent of an organic solvent of the pressure-sensitive adhesive composition onto a substrate and drying it.

(Circular polarizing plate)

The circularly polarizing plate 30 may include a linearly polarizing plate 31 and a retardation layer 32, and the linearly polarizing plate 31 is disposed on the first adhesive layer 20 side, and the retardation layer 32 is provided with a second adhesive. It can be placed on the layer 40 side. The circularly polarizing plate 30 can convert light emitted through the flexible laminate 100 from the display element side of the image display device having the flexible laminate 100 into circularly polarized light. Further, since the circularly polarizing plate 30 can suppress the emission of reflected light of external light, it can impart a function as an antireflection film to the flexible laminate 100.

The circularly polarizing plate 30 preferably has a stiffness of 40 MPa·mm or more at a temperature of 23°C and a relative humidity of 55%, and may be 80 MPa·mm or more, and may be 100 MPa·mm or more, and further 700 MPa·mm. It is preferably mm or less, 600 MPa·mm or less, 500 MPa·mm or less, 400 MPa·mm or less, 200 MPa·mm or less, and 100 MPa·mm or less. When the rigidity of the circularly polarizing plate 30 decreases, the flexibility of the flexible laminate 100 is improved, while the impact resistance tends to decrease. When the rigidity of the circularly polarizing plate 30 increases, the flexible laminate 100 While the impact resistance is improved, the flexibility tends to decrease. In addition, when the rigidity of the circularly polarizing plate 30 is in the above range, the flexible laminate 100 satisfies the above equation (i) or the relationship of the above equations (i) and (ii), A flexible laminate 100 having impact properties and excellent flexibility can be obtained suitably.

The stiffness [MPa·mm] of the circularly polarizing plate 30 is the tensile modulus Ec[MPa] at a temperature of 23°C and a relative humidity of 55% of the circularly polarizing plate 30 and the thickness of the circularly polarizing plate 30 [mm] It can be calculated by the product of and (Ec[MPa]×c[µm]×10 ^{−3 ).}

(Straight polarizing plate)

The linearly polarizing plate 31 has a function of selectively transmitting linearly polarized light in any direction from non-polarized light such as natural light. Examples of the linearly polarizing plate 31 include a stretched film in which a dye having absorption anisotropy is adsorbed, or a film including a film obtained by coating and curing a dye having absorption anisotropy as a polarizer. As a dye having absorption anisotropy, a dichroic dye is mentioned, for example. As the dichroic dye, specifically, iodine or a dichroic organic dye is used. For dichroic organic dyes, C.I. A dichroic direct dye including a diazo compound such as DIRECT RED 39, and a dichroic direct dye including a compound such as tris azo or tetrakis azo are included. As a film to which a dye having absorption anisotropy is applied, which is used as a polarizer, a stretched film in which a dye having absorption anisotropy is adsorbed, a composition containing a dichroic dye having a liquid crystal property, or a dichroic dye and a polymerizable liquid crystal are included. And a film having a layer obtained by applying and curing the composition. A film obtained by coating and curing a dye having absorption anisotropy is preferable because there is no restriction in the bending direction compared to a stretched film in which a dye having absorption anisotropy is adsorbed.

(Polarizing plate provided with a stretched film as a polarizer)

A linearly polarizing plate provided with a stretched film adsorbed with a dye having absorption anisotropy as a polarizer will be described. The stretched film in which a dye having absorption anisotropy, which is a polarizer, is adsorbed is a process of uniaxially stretching a polyvinyl alcohol-based resin film, a process of adsorbing the dichroic dye by dyeing a polyvinyl alcohol-based resin film with a dichroic dye, and It has a process of treating a polyvinyl alcohol-based resin film with a dichroic dye adsorbed thereon with an aqueous boric acid solution, and is produced through a process of washing with water after treatment with an aqueous boric acid solution. Such a polarizer may be used as it is as a linear polarizing plate, or a transparent protective film bonded to one or both sides thereof may be used as a linear polarizing plate. The thickness of the polarizer thus obtained is preferably 2 µm to 40 µm.

Polyvinyl alcohol-based resin is obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably 1,500 to 5,000.

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

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Further, it is also possible to uniaxially stretch in a plurality of these steps. In uniaxial stretching, stretching may be performed uniaxially between rolls having different circumferential speeds, or stretching may be performed uniaxially using a hot roll. Further, uniaxial stretching may be dry stretching performed in the air, or wet stretching performed in a state in which the polyvinyl alcohol-based resin film is swollen using a solvent. The draw ratio is usually about 3 to 8 times.

The thickness of the linearly polarizing plate provided with the stretched film as a polarizer may be, for example, 1 µm or more and 100 µm or less, 5 µm or more, 7 µm or more, 700 µm or less, 50 µm or less, and 20 It may be µm or less, or 10 µm or less. The tensile modulus at a temperature of 25°C of the linearly polarizing plate provided with the stretched film as a polarizer may be, for example, 1 GPa or more and 20 GPa or less.

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

(A polarizing plate having a film formed of a liquid crystal layer as a polarizer)

A linearly polarizing plate including a film formed of a liquid crystal layer as a polarizer will be described. As a film coated with a dye having absorption anisotropy, which is used as a polarizer, a composition containing a dichroic dye having liquid crystal properties, or a film obtained by applying a composition containing a dichroic dye and a liquid crystal compound to a substrate and curing, etc. Can be lifted. This film may be used as a linearly polarizing plate by peeling the base material or as a linearly polarizing plate with the base material, or having a protective film on one or both sides thereof. As said protective film, the same thing as a linear polarizing plate provided with the said stretched film as a polarizer is mentioned.

As a film obtained by applying the dye having absorption anisotropy, specifically, a film described in Japanese Patent Application Laid-Open No. 2013-37353 or Japanese Patent Application Laid-Open No. 2013-33249 can be mentioned.

The film obtained by coating and curing a dye having absorption anisotropy is preferably thinner, but if it is too thin, the strength tends to decrease and workability 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. The thickness of the linearly polarizing plate provided with the film formed of the liquid crystal layer as a polarizer may be, for example, 1 µm or more and 50 µm or less, and the linearly polarizing plate provided with the film formed of the liquid crystal layer as a polarizer at a temperature of 23°C and a relative humidity of 55%. The tensile modulus may be, for example, 0.5 GPa or more and 5 GPa or less.

(Phase difference layer)

The phase difference layer 32 may be one layer or two or more layers. Moreover, you may have an overcoat layer which protects the surface of a retardation layer, or a base film which supports a retardation layer. The retardation layer 32 includes a λ/4 layer, and may further include a λ/2 layer or a positive C layer. When the retardation layer 32 includes a λ/2 layer, a λ/2 layer and a λ/4 layer are sequentially stacked from the linear polarizing plate 31 side. When the retardation layer 32 includes a positive C layer, a λ/4 layer and a positive C layer may be sequentially stacked from the side of the linear polarizing plate 31, and a positive C layer and a λ/ layer sequentially from the side of the linear polarizing plate 31 Four layers may be laminated.

The retardation layer 32 may be formed of a resin film exemplified as a material of the above-described protective film, or may be formed of a layer in which a polymerizable liquid crystal compound is cured. The retardation layer 32 may further include an alignment film or a base film, or may have a bonding layer for bonding the λ/4 layer and the λ/2 layer. The bonding layer is an adhesive layer or an adhesive layer, and can be formed using the above-described adhesive composition or a known adhesive composition. As known adhesive compositions, water-based adhesive compositions such as polyvinyl alcohol-based resin aqueous solution and aqueous two-component urethane-based emulsion adhesive; And an active energy ray-curable adhesive composition that is cured by irradiation with an active energy ray such as ultraviolet rays.

The thickness of the entire retardation layer may be, for example, 1 µm or more and 50 µm or less.

(2nd adhesive layer)

The second adhesive layer 40 is a layer for bonding the circularly polarizing plate 30 and the TS panel 50, and can be formed using an adhesive composition. The thickness d of the second pressure-sensitive adhesive layer 40 is not particularly limited as long as it can satisfy the relationship of the above formulas (i) and (ii), but is preferably 5 µm or more, and may be 10 µm or more, and 15 µm or more. It may be, it may be 20 µm or more, and it is usually 100 µm or less, preferably 80 µm or less, and more preferably 60 µm or less.

The second pressure-sensitive adhesive layer 40 preferably has a storage modulus Gd at a temperature of 25°C and a relative humidity of 50% of 0.01 MPa or more, 0.02 MPa or more, 0.03 MPa or more, 0.05 MPa or more, and further , 0.2 MPa or less is preferable, 0.15 MPa or less may be sufficient, 0.12 MPa or less may be sufficient, and 0.10 MPa or less may be sufficient as it.

When the storage elastic modulus Gd of the second pressure-sensitive adhesive layer 40 decreases, the impact resistance of the flexible laminate 100 tends to decrease, and when the storage elastic modulus Gd of the second pressure-sensitive adhesive layer 40 increases, the flexible laminate 100 ) Tends to decrease. In addition, when the storage elastic modulus Gd of the second pressure-sensitive adhesive layer 40 is in the above range, the flexible laminate 100 satisfies the above equation (i) or the relationship of the above equations (i) and (ii). By doing so, it is possible to suitably obtain a flexible laminate 100 having impact resistance and excellent flexibility.

As the pressure-sensitive adhesive composition constituting the second pressure-sensitive adhesive layer 40, those exemplified as the pressure-sensitive adhesive composition constituting the first pressure-sensitive adhesive layer 20 can be used. The pressure-sensitive adhesive composition constituting the second pressure-sensitive adhesive layer 40 may be the same as or different from the pressure-sensitive adhesive composition constituting the first pressure-sensitive adhesive layer 20. In addition, the formation of the second adhesive layer 40 can be performed in the same manner as the formation of the first adhesive layer 20.

(Touch sensor panel)

If the TS panel 50 is a sensor capable of detecting the touched position, the detection method is not limited, and the resistive film method, capacitive coupling method, optical sensor method, ultrasonic method, electromagnetic inductive coupling method, surface acoustic wave method, etc. The TS panel of is illustrated. Because of its low cost, a resistive film type and a capacitive coupling type TS panel are suitably used.

An example of a resistive TS panel is 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 entire inner surface of each substrate, and touch It is composed of a position detection circuit. In the image display device provided with the resistive film type touch sensor panel, when the surface of the front plate 10 is touched, the opposing resistive film is short-circuited, and a current flows through the resistive film. The touch position detection circuit detects a change in voltage at this time, and the touched position is detected.

An example of a capacitive coupling method TS panel is constituted by a substrate, a position detecting transparent electrode provided on the entire surface of the substrate, and a touch position detecting circuit. In the image display device provided with the capacitive coupling type TS panel, when the surface of the front plate 10 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 TS panel 50 may be composed of only a touch sensor pattern layer, or may include a touch sensor pattern layer and a support layer that supports the touch sensor pattern layer. When the TS panel 50 includes a touch sensor pattern layer and a support layer, both may be bonded by a bonding layer, or a touch sensor pattern layer may be formed on the support layer without passing through the bonding layer. The bonding layer is an adhesive layer or an adhesive layer, and can be formed using the above-described adhesive composition and adhesive composition.

The touch sensor pattern layer of the TS panel 50 may include a conductive layer such as electrodes or wiring. It is preferable that the conductive layer is formed so as not to be visually recognized when used as the TS panel 50 for a flexible laminate. The touch sensor pattern layer may include a separation layer. The separation layer is formed on a substrate such as glass, and may be provided to separate the touch sensor pattern layer formed on the separation layer from the substrate together with the separation layer. The separation layer is preferably an inorganic material layer or an organic material layer. Examples of the material for forming the inorganic material layer include silicon oxide. As a material for forming the organic material layer, for example, a (meth)acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like can be used. The touch sensor pattern layer may also include at least one protective layer. The protective layer can be provided to support the conductive layer in contact with the conductive layer. The protective layer includes at least one of an organic insulating film and an inorganic insulating film, and these films can be formed by a spin coating method, a sputtering method, a vapor deposition method, or the like. The conductive layer may be a transparent conductive layer containing a metal oxide such as ITO, or a metal layer containing a metal such as aluminum, copper, silver, or gold. In addition, the touch sensor pattern layer may be composed of only conductive layers such as electrodes and wiring. The support layer is preferably a resin film, and for example, a polyester resin film such as a cyclic olefin resin film and a polyethylene terephthalate resin film, an acrylic resin film, a triacetyl cellulose resin film, or the like can be used.

The TS panel 50 preferably has a stiffness of 15 MPa·mm or more at a temperature of 23°C and a relative humidity of 55%, 50 MPa·mm or more, 100 MPa·mm or more, and 700 MPa or less. It is preferably 600 MPa·mm or less, or 500 MPa·mm or less. When the rigidity of the TS panel 50 decreases, the flexibility of the flexible laminate 100 improves, while the impact resistance tends to decrease. When the rigidity of the TS panel 50 increases, the flexible laminate 100 While the impact resistance is improved, the flexibility tends to decrease. In addition, when the rigidity of the TS panel 50 is in the above range, the flexible laminate 100 satisfies the above formula (i) or the relationship of the above formulas (i) and (ii), A flexible laminate 100 having impact properties and excellent flexibility can be obtained suitably.

The rigidity [MPa·mm] of the TS panel 50 is the product of the tensile modulus Ee [MPa] and the thickness [mm] of the TS panel 50 at a temperature of 23°C and a relative humidity of 55% of the TS panel 50 It can be calculated by (Ee[MPa]×e[µm]×10 ^{−3 ).} The thickness e of the TS panel 50 may be, for example, 3 µm or more and 100 µm or less, 5 µm or more and 50 µm or less, 5 µm or more and 30 µm or less, and 5 µm or more and 20 µm or less. The tensile modulus Ee of the touch sensor panel may be, for example, 1 GPa or more and 7 GPa or less, or 1.2 GPa or more and 6 GPa or less.

(Image display device)

2 is a schematic cross-sectional view schematically showing an example of the image display device of the present embodiment. The image display device 300 includes a flexible laminate 100 including a front plate 10 disposed on the front (viewer side) thereof, a display laminate 200 including a display unit, and a bonding layer 60 ), the display laminate 200 is laminated on the circular polarizing plate 50 side of the flexible laminate 100 via the bonding layer 60. Such an image display device 300 can be a touch panel display device since the flexible laminate 100 includes the TS panel 50.

The image display device 300 may be a flexible display panel. The image display device, which is a flexible display, may be configured to be folded and stacked with the surface of the front plate 10 inward, or may be configured to be wound with the surface of the front plate 10 inward.

The bonding layer 60 is for bonding the circularly polarizing plate 30 and the display laminate 200 in the flexible laminate 100. When laminating the flexible laminate 100 and the display laminate 200, for example, a bonding layer 60 is formed on the circularly polarizing plate 30 of the flexible laminate 100, and on the bonding layer 60 The display laminate 200 may be laminated. The bonding layer 60 is a pressure-sensitive adhesive layer or an adhesive layer, and may be formed using the pressure-sensitive adhesive composition and the adhesive composition described above.

Examples of the display unit included in the display laminate 200 include a display unit including display elements such as a liquid crystal display element, an organic EL display element, an inorganic EL display element, a plasma display element, and a field emission display element.

The image display device 300 can be used as a mobile device such as a smartphone or a tablet, a television, a digital photo frame, an electronic signboard, a measuring device or a measuring device, an office device, a medical device, a computer device, or the like.

[Example]

Hereinafter, the present invention will be described in more detail by examples, but the present invention is not limited by these examples. In Examples and Comparative Examples, "%" and "parts" are mass% and parts by mass, unless otherwise specified.

[Measurement of thickness]

The thickness of each layer constituting the flexible laminate was measured in the following procedure. The flexible laminate was cut using a laser cutter, and the cross-section of the cut flexible laminate was observed using a transmission electron microscope (SU8010, manufactured by Horiba Seisakusho Co., Ltd.), and from the obtained observation image, the flexible laminate The thickness of each layer constituting the was measured.

[Measurement of tensile modulus]

The tensile modulus of elasticity was measured using a tensile tester (AG-1S, manufactured by Shimadzu Corporation) at a temperature of 23°C and a relative humidity of 55%. When the measurement object was a retardation layer, the tensile modulus in the slow axis direction was measured.

[Calculation of stiffness]

Stiffness was calculated by calculating the product of the value of the thickness measured above and the value of the tensile modulus.

[Measurement of storage modulus]

For a measurement sample in which each adhesive layer (first adhesive layer or second adhesive layer) is stacked to have a thickness of 150 μm, using a rheometer (Anton Parr, MCR-301), a temperature of 25°C and a relative humidity of 50% , Stress 1%, the storage modulus (Gb, Gd) was measured under the conditions of a frequency of 1 Hz.

[Impact resistance test]

On glass (Soda Glass 1.1T, manufactured by JMC Glass), using an optical adhesive sheet (8146-04, manufactured by 3M) having a thickness of 100 μm, the touch sensor panel of the flexible laminate obtained in each Example and Comparative Example The side was fixed, and a sample for evaluation was prepared. After installing this sample for evaluation in an impact-resistant tester (Drop Tester, manufactured by TAEWON TECH CO.) with the front plate side up, free the test sphere at a position 5 cm above the surface of the front plate side of the evaluation panel. The impact resistance test of falling and colliding with the sample for evaluation was performed at a temperature of 25°C. This impact resistance test was conducted while changing the weight of the test sphere to determine the weight of the test sphere when the glass in the lower part of the sample for evaluation was broken. The weight of the test sphere when the glass of the evaluation sample is broken,

A for 100 g or more,

B when it is more than 50 g and less than 100 g,

C for less than 50 g

And evaluated the impact resistance.

[Bending test]

(1) Flexibility (in) test

At a temperature of 25°C, in order to evaluate the bendability (in) to be bent with the front plate side as the inside, a flexural (in) test was performed in the following procedure. In a bending tester (CFT-720C, manufactured by Covotech), the flexible laminate obtained in each Example and Comparative Example was installed in a flat state (not bent), and the front plate side was inward to face when bending. After bending the flexible laminate so that the distance between the front plates was 4.0 mm, a bending operation was performed to return it to its original flat state. When this bending operation was performed once, the number of bending was counted as one, and this bending operation was repeatedly performed. The number of bending when cracks or lifting of the pressure-sensitive adhesive layer occurred in the region bent by the bending operation was confirmed as the limiting bending number. Occurrence of cracks or lifting of the pressure-sensitive adhesive layer in the curved area due to the bending operation,

A, if the number of bends is not visible even when the number of bends reaches 200,000,

B, if the number of bends is more than 100,000 and less than 200,000,

C, the case where the number of bends is more than 50,000 and less than 100,000,

D if the number of bends is less than 50,000

And evaluation of the flexural test (in) was performed.

(2) Flexibility (out) test

In order to evaluate the bendability (out) of bending the front plate side to the outside, when the front plate side is bent to the outside, an operation of bending the flexible laminate so that the distance between the TS panel sensors is 4.0 mm is performed. Except that, the bending operation was repeated in the same procedure as in the above (1) flexural (in) test, and the number of limit bending was confirmed. The evaluation of the flexural (out) test was also performed in the same manner as the evaluation of the flexural (in) test.

[Example 1]

(Preparation of the front panel)

As the front plate, a resin film with a hard coat layer having a thickness of 60 µm in which a hard coat layer was formed on one side of the resin film was prepared. The resin film was a polyimide resin film having a thickness of 50 μm, and the hard coat layer was a layer formed of a composition containing a dendrimer compound having a thickness of 10 μm and having a polyfunctional acrylic group at the terminal.

(Preparation of the first adhesive layer)

On the release film, the acrylic pressure-sensitive adhesive composition was applied and dried to prepare a first pressure-sensitive adhesive layer with a release film in which the first pressure-sensitive adhesive layer was formed. The thickness of the first pressure-sensitive adhesive layer was 50 µm, and the storage modulus Gb at a temperature of 25°C and a relative humidity of 50% was 0.09 MPa.

(Preparation of circular polarizing plate)

A polyvinyl alcohol (PVA) film having an average polymerization degree of about 2,400, a saponification degree of 99.9 mol% or more, and a thickness of 20 μm was prepared. After the PVA film was immersed in pure water at 30°C, iodine dyeing was performed by immersing at 30°C in an aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.02/2/100 (iodine dyeing step). The PVA film which had undergone the iodine dyeing step was immersed in an aqueous solution having a mass ratio of potassium iodide/boric acid/water of 12/5/100 at 56.5°C to perform boric acid treatment (boric acid treatment step). After washing the PVA film which passed through the boric acid treatment process with 8 degreeC pure water, it dried at 65 degreeC, and the polarizer in which iodine adsorption|orientation to polyvinyl alcohol was obtained. The stretching of the PVA film was performed in an iodine dyeing step and a boric acid treatment step. The total draw ratio of the PVA film was 5.3 times. The thickness of the obtained polarizer was 7 µm.

The polarizer obtained above and a 13 µm-thick cycloolefin polymer (COP) film (ZF-14, manufactured by Nippon Xeon Co., Ltd., an in-plane phase difference value at a wavelength of 550 nm of 1 nm) were bonded with a nip roll through a water-based adhesive. . While maintaining the tension of the obtained bonded product at 430 Nm, it was dried at 60° C. for 2 minutes to obtain a linear polarizing plate having a COP film on one side. In addition, water-based adhesive is 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol ("Kurarepoval KL318", manufactured by Kuraray Co., Ltd.), and water-soluble polyamide epoxy resin ("Sumirez Resin 650" (solid content concentration 30). % Aqueous solution), and 1.5 parts of Taoka Chemical Industry Co., Ltd. make) were added and it prepared.

On the polarizer side of the linear polarizing plate obtained above, a retardation film was laminated through an adhesive layer. The retardation film used was that the λ/2 layer and the λ/4 layer were bonded to each other through an ultraviolet curable adhesive. The λ/2 layer had a layer and an alignment film cured by a liquid crystal compound, and had a thickness of 3 µm. The pressure-sensitive adhesive layer had a thickness of 5 µm and a storage modulus of 0.6 MPa at a temperature of 25°C and a relative humidity of 50%. The λ/4 layer had a layer and an alignment film cured by a liquid crystal compound, and had a thickness of 2 µm.

(Preparation of the second adhesive layer)

On the release film, the acrylic pressure-sensitive adhesive composition was applied and dried to prepare a second pressure-sensitive adhesive layer with a release film in which the second pressure-sensitive adhesive layer was formed. The thickness of the second pressure-sensitive adhesive layer was 10 µm, and the storage modulus Gd at a temperature of 25°C and a relative humidity of 50% was 0.1 MPa.

(Preparation of the touch sensor panel)

A touch sensor pattern layer was prepared as a TS panel. The touch sensor pattern layer includes an ITO layer as a transparent conductive layer and a cured layer of an acrylic resin composition as a separation layer, and has a thickness of 7 μm, a tensile modulus of 4510 MPa at a temperature of 23°C and a relative humidity of 55%. Was. The rigidity of the TS panel was 31.6 MPa·mm.

(Fabrication of flexible laminate)

Corona treatment was performed on one side of the front plate and the side of the first pressure-sensitive adhesive layer with a release film on the side of the first pressure-sensitive adhesive layer, and the corona-treated surfaces were bonded to each other. Then, the release film adhered to the first pressure-sensitive adhesive layer is peeled off, corona treatment is performed on the exposed side and the side of the linearly polarizing plate side of the circularly polarizing plate, and the corona-treated surfaces are bonded to each other to form a composite of the front plate and the circularly polarizing plate. Got it. Next, corona treatment was performed on the surface on the λ/4 layer side of the composite and the surface on the second adhesive layer side of the second adhesive layer with a release film, and the corona treated surfaces were bonded together. Next, the release film adhered to the second pressure-sensitive adhesive layer was peeled off, corona treatment was performed on the exposed surface, and the corona treatment surface and the transparent conductive layer side of the TS panel were bonded to each other to obtain a flexible laminate. In addition, all of the corona treatments performed above were performed with a frequency of 20 kHz, a voltage of 8.6 kV, a power of 2.5 kW, and a speed of 6 m/min.

The obtained flexible laminate was the total thickness t [㎛] of the front plate 10, the first adhesive layer 20, the circularly polarizing plate 30, the second adhesive layer 40, and the TS panel 50 (the above formula ( The thickness indicated by iii)) was 157 µm and 177 mm long x 105 mm wide. Regarding the flexible laminate, an impact resistance test, a flexural (in) test, and a flexural (out) test were performed. The results are shown in Table 1.

[Examples 2 to 9, Comparative Example 1]

As the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, those having the thickness shown in Table 1 and storage modulus at a temperature of 25°C are used, and as a front plate, on one side of a resin film having the thickness shown in Table 1, Table 1 A flexible laminate was produced in the same procedure as in Example 1, except that the one formed with the hard coat layer of the thickness described in was used, and the one having the thickness and rigidity described in Table 1 was used as the TS panel. The resin films used for the front plate were all polyimide resin films, and the hard coat layers used for the front plate were all layers formed of a composition containing a dendrimer compound having a polyfunctional acrylic group at the terminal. The obtained flexible laminate was subjected to an impact resistance test, a flexural (in) test, and a flexural (out) test. The results are shown in Table 1.

10: front plate, 20: first adhesive layer, 30: circularly polarizing plate, 31: linearly polarizing plate, 32: retardation layer, 40: second adhesive layer, 50: touch sensor panel, 60: bonding layer, 100: flexible laminate , 200: display laminate, 300: image display device.

Claims (10)

A flexible laminate comprising a front plate, a first adhesive layer, a circularly polarizing plate, a second adhesive layer, and a touch sensor panel in this order,
The thickness of the front plate is a[㎛], the thickness of the first adhesive layer is b[㎛], the thickness of the circularly polarizing plate is c[㎛], the thickness of the second adhesive layer is d[㎛] and the touch When the thickness of the sensor panel is e[µm], and the tensile modulus at a temperature of 23°C and a relative humidity of 55% of the front plate is Ea[GPa], the following equation (i):
{Ea×(a+b)}/(a+b+c+d+e)≥1.5 (i)
A flexible laminate that satisfies the relationship of. The method of claim 1, wherein the tensile modulus Ea[GPa] of the front plate, the thickness b of the first adhesive layer, and the thickness d of the second adhesive layer are the following formula (ii):
b/(Ea×d)≥0.3 (ii)
A flexible laminate that satisfies the relationship of. The stiffness according to claim 1 or 2, at a temperature of 23°C and a relative humidity of 55% of the front plate is 0.09 GPa·mm or more and 0.7 GPa·mm or less,
The stiffness of the circularly polarizing plate at a temperature of 23° C. and a relative humidity of 55% is 40 MPa·mm or more and 400 MPa·mm or less,
A flexible laminate having a rigidity of 15 MPa·mm or more and 700 MPa·mm or less of the touch sensor panel at a temperature of 23°C and a relative humidity of 55%. The storage modulus of claim 1 or 2, wherein the first pressure-sensitive adhesive layer has a storage elastic modulus of 0.01 MPa or more and 0.15 MPa or less at a temperature of 25° C. and a relative humidity of 50%,
The flexible laminate having a storage modulus of the second pressure-sensitive adhesive layer at a temperature of 25° C. and a relative humidity of 50% is 0.01 MPa or more and 0.15 MPa or less. The method of claim 1 or 2, wherein a thickness of the front plate a, a thickness b of the first adhesive layer, a thickness c of the circularly polarizing plate, a thickness d of the second adhesive layer, and a thickness e of the touch sensor panel The total thickness t [µm] is represented by the following formula (iii):
t=a+b+c+d+e (iii)
When represented by, t is a flexible laminate of 250 μm or less. The flexible laminate according to claim 1 or 2, wherein the front plate is a resin film or a resin film with a hard coat layer having a hard coat layer on at least one surface of the resin film. The flexible laminate according to claim 1 or 2, wherein the flexible laminate has a limit of bending times of 50,000 or more in a flexural test in which the front plate side is inwardly bent. The flexible laminate according to claim 1 or 2, wherein the flexible laminate has a limit of bending times of 50,000 or more in a flexural test in which the front plate side is bent outside. The method according to claim 1 or 2, wherein the circularly polarizing plate includes a linearly polarizing plate and a retardation layer in order from the side of the first pressure-sensitive adhesive layer,
The linearly polarizing plate is a flexible laminate comprising a protective film and a polarizer in order from the side of the first adhesive layer. An image display device comprising the flexible laminate according to claim 1 or 2, wherein the front plate is disposed on the entire surface.

Images