WO2020195699A1

WO2020195699A1 - Layered body and display device

Info

Publication number: WO2020195699A1
Application number: PCT/JP2020/009630
Authority: WO
Inventors: 柱烈張; 恩瑛金; ▲ビョン▼▲フン▼ 宋
Original assignee: 住友化学株式会社
Priority date: 2019-03-26
Filing date: 2020-03-06
Publication date: 2020-10-01
Also published as: JP2020157579A; TW202040188A; KR20210144728A; CN113613879A

Abstract

The objective of the present invention is to provide a layered body wherein the occurrence of cracks in a coating layer caused by bending has been suppressed, and a display device equipped with same. The present invention provides a layered body comprising a first protective layer, a first adhesive layer, an intercalated coating layer, a base material layer, a second adhesive layer, and a second protective layer, in this order, each of the layers being in contact with one another. When G'1 (kPa) is the storage modulus for the first adhesive layer at a temperature of 25°C, G'2 (kPa) is the storage modulus for the second adhesive layer at a temperature of 25°C, a1 (μm) is the thickness of the first adhesive layer, and a2 (μm) is the thickness of the second adhesive layer, the evaluation parameters A1 and A2 represented by formula (1) and formula (2) fulfill the relationships in formula (3), formula (4), and formula (5). (1) A1 = G'1/a1 (2) A2 = G'2/a2 (3) A1+A2 ≤ 230 (4) A2-A1 ≥ 0 (5) A1 ≤ 20

Description

Laminates and display devices

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

In Japanese Patent Application Laid-Open No. 2018-10117 (Patent Document 1), a transparent film base material is bonded onto a polarizing plate via a first adhesive sheet, and a front transparent member is attached to the transparent film base material via a second adhesive sheet. The image display device to which the above is attached is disclosed. Japanese Unexamined Patent Publication No. 2018-028573 (Patent Document 2) discloses a laminate for an image display device including a plurality of pressure-sensitive adhesive layers and an optical film containing a polarizing film.

Japanese Unexamined Patent Publication No. 2018-10117 Japanese Unexamined Patent Publication No. 2018-028573

In the laminated body, a method of forming a layer constituting the laminated body by a thin film coating is adopted in order to realize thinning and weight reduction. However, there is a problem that cracks are likely to occur in the coating layer when the laminate including the coating layer is bent.

An object of the present invention is to provide a laminated body in which the generation of cracks due to bending is suppressed in the coating layer and a display device provided with the same.

The present invention provides the following laminates and display devices.
[1] A laminate comprising a first protective layer, a first pressure-sensitive adhesive layer, an intervening coating layer, a base material layer, a second pressure-sensitive adhesive layer, and a second protective layer in this order.
Each layer is in contact with each other
The storage elastic modulus of the first pressure-sensitive adhesive layer at a temperature of 25 ° C. is G'1 [kPa], and the storage elastic modulus of the second pressure-sensitive adhesive layer at a temperature of 25 ° C. is G'2 [kPa]. When the thickness of the agent layer is a1 [μm] and the thickness of the second pressure-sensitive adhesive layer is a2 [μm], the following formulas (1) and (2):
A1 = G'1 / a1 (1)
A2 = G'2 / a2 (2)
The evaluation parameters A1 and A2 represented by are expressed by the following equations (3), (4) and (5):
A1 + A2 ≤ 230 (3)
A2-A1 ≧ 0 (4)
A1 ≤ 20 (5)
A laminate that meets the requirements.
[2] The laminate according to [1], wherein the first protective layer contains a window film having a tensile elastic modulus of 4.0 GPa or more.
[3] The laminate according to [1] or [2], wherein the second protective layer includes a back plate having a tensile elastic modulus of 4.0 GPa or more.
[4] The laminate according to any one of [1] to [3], wherein the intervening coating layer is composed of one or more layers, and the thickness of each layer is 5 μm or less.
[5] The laminate according to any one of [1] to [4], wherein the intervening coating layer includes a polarizer layer, a retardation layer, or a touch sensor panel.
[6] The laminate according to any one of [1] to [5], wherein the G'1 and the G'2 are 10000 kPa or less, respectively.
[7] A display device including the laminate according to any one of [1] to [6].

According to the present invention, it is possible to provide a laminated body in which the generation of cracks due to bending is suppressed in the coating layer and a display device provided with the laminated body.

It is the schematic sectional drawing which shows an example of the laminated body which concerns on this invention. It is the schematic sectional drawing which shows the laminated body of Example 1-1. It is the schematic sectional drawing which shows the laminated body of Example 2-1. It is the schematic explaining the method of a flexibility test.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Laminated body>
FIG. 1 shows a schematic cross-sectional view of a laminate (optical laminate) according to one aspect of the present invention. The laminate 100 includes a first protective layer 10, a first adhesive layer 11, an intervening coating layer 12, a base material layer 15, a second adhesive layer 13, and a second protective layer 14 in this order. .. The layers are in contact with each other. Hereinafter, the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 may be collectively referred to as a pressure-sensitive adhesive layer.

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, 30 μm or more and 1000 μm or less, preferably 40 μm or more and 500 μm or less, and more preferably 50 μm or more. It is 300 μm or less.

The plan view shape of the laminated body 100 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 laminated body 100 in the surface 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 laminate may have corners R-processed, end portions notched, or perforated.

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 display device may have a touch panel function.

[Evaluation parameters of adhesive layer]
In the laminate 100, the storage elastic modulus of the first pressure-sensitive adhesive layer 11 at a temperature of 25 ° C. is G'1 [kPa], and the storage elastic modulus of the second pressure-sensitive adhesive layer 13 at a temperature of 25 ° C. is G'2 [kPa]. When the thickness of the first pressure-sensitive adhesive layer 11 is a1 [μm] and the thickness of the second pressure-sensitive adhesive layer 13 is a2 [μm], the following formulas (1) and (2):
A1 = G'1 / a1 (1)
A2 = G'2 / a2 (2)
The evaluation parameters A1 and A2 represented by are expressed by the following equations (3), (4) and (5):
A1 + A2 ≤ 230 (3)
A2-A1 ≧ 0 (4)
A1 ≤ 20 (5)
Meet. The storage elastic modulus of the pressure-sensitive adhesive layer and the thickness of the layer are measured according to the measuring method described in the column of Examples described later.

The laminate 100 preferably has the following formula (3'):
A1 + A2 ≤ 130 (3')
Meet.

The laminate 100 preferably has the following formula (4'):
A2-A1 ≧ 100 (4')
Meet.

The laminate 100 preferably has the following formula (5'):
A1 ≤ 5 (5')
Meet.

In such a laminated body 100, even if the first protective layer 10 is bent inside, cracks are less likely to occur in the intervening coating layer 12, that is, the flexibility is excellent. When the laminate containing the coating layer is repeatedly bent, cracks may occur in the coating layer. In the laminate 100, the evaluation parameters A1 and A2 of the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 increase as the storage elastic modulus increases, and increase as the layer thickness decreases. That is, the larger A1 and A2, the harder the pressure-sensitive adhesive layer tends to be, and the smaller A1 and A2, the softer the pressure-sensitive adhesive layer tends to be. When the laminate is bent, the present inventors increase the tensile stress of the coating layer when the coating layer is adjacent to the outside of the relatively hard pressure-sensitive adhesive layer with reference to the bending axis. It was found that cracks are likely to occur. On the contrary, when the laminated body is bent, if the coating layer is adjacent to the inside of the relatively hard adhesive layer with reference to the bending axis, the tensile stress of the coating layer decreases and cracks occur. I found it difficult to do. Therefore, when the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 satisfy the above formulas (3), (4) and (5), the intervening coating layer 12 sandwiched between them has an increased tensile stress. It was found that it was difficult and even if the first protective layer was repeatedly bent inward, the occurrence of cracks was suppressed.

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

According to the laminate according to the present invention, the crack resistance of the coating layer is improved to the extent that cracks do not occur even if the laminate is repeatedly bent 200,000 times or more with a bending radius of 1 mm according to the test method described in the column of Examples described later. Can be made to. In the present invention, the cracks generated in the coating layer include cracks generated in the coating layer and peeling between the coating layer and the pressure-sensitive adhesive layer.

The first pressure-sensitive adhesive layer 11 is formed from the first pressure-sensitive adhesive composition, and the second pressure-sensitive adhesive layer 13 is formed from the second pressure-sensitive adhesive composition. The first pressure-sensitive adhesive composition and the second pressure-sensitive adhesive so that the evaluation parameters A1 and A2 of the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 13 satisfy the formulas (3), (4) and (5). As a method for preparing the composition, for example, the pressure-sensitive adhesive layer is composed of the pressure-sensitive adhesive composition described later, the type of monomer constituting the (meth) acrylic polymer described later is changed, or the (meth) acrylic polymer is prepared. Examples thereof include a method of adjusting the molecular weight, a method of adjusting the thickness of the pressure-sensitive adhesive layer, a method of combining these, and the like.

[First adhesive layer]
When the laminate has a structure in which the pressure-sensitive adhesive layer, the coating layer, the thermoplastic resin film, and the pressure-sensitive adhesive layer are in contact with each other in this order, the pressure-sensitive adhesive layer in contact with the coating layer is the first. 1 Adhesive layer 11 is used. The first pressure-sensitive adhesive layer 11 may be the following pressure-sensitive adhesive layer.

The storage elastic modulus G'1 of the first pressure-sensitive adhesive layer 11 at a temperature of 25 ° C. is usually 10 kPa or more, preferably 30 kPa or more. The storage elastic modulus G'1 of the first pressure-sensitive adhesive layer 11 at a temperature of 25 ° C. is usually 10000 kPa or less, more preferably 5000 kPa or less, and further preferably 1000 kPa or less. The storage elastic modulus of the pressure-sensitive adhesive layer is measured according to the method described in the column of Examples described later. If the storage elastic modulus G'1 is too small, the processability of the laminated body tends to decrease. For example, when cutting, the end of the adhesive falls off from the laminated body (glue removal), making it difficult to peel off the release film. It becomes easy for the laminate to become dirty. If the storage elastic modulus G'1 is too large, the flexibility of the laminated body tends to decrease.

The thickness a1 of the first pressure-sensitive adhesive layer 11 may be 1 μm or more, preferably 3 μm or more. The thickness a1 of the first pressure-sensitive adhesive layer 11 may be 100 μm or less, preferably 50 μm or less.

[Second adhesive layer]
When the laminate has a structure in which the pressure-sensitive adhesive layer, the coating layer, the thermoplastic resin film, and the pressure-sensitive adhesive layer are in contact with each other in this order, the pressure-sensitive adhesive layer in contact with the thermoplastic resin film. Is the second pressure-sensitive adhesive layer 13. The second pressure-sensitive adhesive layer 13 may be the following pressure-sensitive adhesive layer.

The storage elastic modulus G'2 of the second pressure-sensitive adhesive layer 13 at a temperature of 25 ° C. is usually 10 kPa or more, preferably 30 kPa or more. The storage elastic modulus G'2 of the second pressure-sensitive adhesive layer 13 at a temperature of 25 ° C. is usually 10000 kPa or less, more preferably 5000 kPa or less, and further preferably 1000 kPa or less. The storage elastic modulus of the pressure-sensitive adhesive layer is measured according to the method described in the column of Examples described later. If the storage elastic modulus G'2 is too small, the processability of the laminated body tends to decrease. For example, when cutting, the end of the adhesive falls off from the laminated body (glue removal), making it difficult to peel off the release film. It becomes easy for the laminate to become dirty. If the storage elastic modulus G'2 is too large, the flexibility of the laminated body tends to decrease.

The thickness a2 of the second pressure-sensitive adhesive layer 13 may be 1 μm or more, preferably 3 μm or more. The thickness a2 of the second pressure-sensitive adhesive layer 13 may be 100 μm or less, preferably 50 μm or less.

[Intervening coating layer]
When the laminate has a structure in which the pressure-sensitive adhesive layer, the coating layer, the thermoplastic resin film, and the pressure-sensitive adhesive layer are in this order and are in contact with each other, the first pressure-sensitive adhesive layer 11 and the second The coating layer interposed between the pressure-sensitive adhesive layer 13 is referred to as an intervening coating layer 12. The coating layer is a layer other than the pressure-sensitive adhesive layer formed by including the step of applying the coating liquid. The intervening coating layer 12 can include a polarizer layer, a retardation layer, a touch sensor panel, an adhesive layer, or a coloring layer, preferably including the following polarizer layer, a retardation layer or a touch sensor panel, and more. It preferably includes a retardation layer or a touch sensor panel. The colored layer can be a layer that shields wiring or the like arranged in a non-display area of the image display device. By arranging the colored layer on the peripheral edge of the laminated body, light leakage can be suppressed, and the colored layer can be visually recognized like a frame, so that the design can be improved.

The coating method includes a coating method, a printing method, a vapor deposition method, and the like. The coating methods include bar coating method, knife coating method, blade coating method, die coating method, direct gravure coating method, reverse gravure coating method, roll coating method, CAP coating method, spin coating method, spray coating method, and screen coating method. Examples include the slit coating method and the dip coating method. Examples of the printing method include an offset printing method, a gravure printing method, a screen printing method, and an inkjet printing method. Examples of the vapor deposition method include a sputtering method, a physical vapor deposition method (PVD), a chemical vapor deposition method (CVD), and a plasma CVD method (PECVD).

The intervening coating layer 12 is composed of one or more layers. The thickness of each layer is usually 5 μm or less. The thickness of each layer is usually 0.01 μm or more. The thickness of the intervening coating layer 12 is preferably 1 μm or more and 20 μm or less, and can be 10 μm or less. When the intervening coating layer 12 includes a polarizer layer, the thickness of the intervening coating layer 12 is, for example, 1 μm or more and 15 μm or less. When the intervening coating layer 12 includes a retardation layer, the thickness of the intervening coating layer 12 is, for example, 1 μm or more and 8 μm or less. When the intervening coating layer 12 includes the touch sensor panel, the thickness of the intervening coating layer 12 is, for example, 15 μm or less.

[Base material layer]
When the laminate has a structure in which the pressure-sensitive adhesive layer, the coating layer, the thermoplastic resin film, and the pressure-sensitive adhesive layer are in this order and are in contact with each other, the first pressure-sensitive adhesive layer 11 and the second The thermoplastic resin film between the pressure-sensitive adhesive layer 13 and the pressure-sensitive adhesive layer 13 is used as the base material layer 15. The base material layer 15 is usually a base material to which the above coating liquid is applied. The base material layer 15 may be the following base material film.

[First protective layer]
The entire structural portion that is a part of the laminate and is in contact with the first pressure-sensitive adhesive layer 11 and exists on the side opposite to the intervening coating layer 12 side is designated as the first protective layer 10. When there are a plurality of layers on the side opposite to the intervening coating layer 12 side with the first pressure-sensitive adhesive layer 11 interposed therebetween, all of them are designated as the first protective layer 10. The first protective layer 10 may include one or more of the following front plate, base film, pressure-sensitive adhesive layer, polarizer layer, retardation layer, touch sensor panel, bonding layer, back plate and the like. The first protective layer 10 preferably includes a front plate.

[Second protective layer]
The entire structural portion that is a part of the laminate and is in contact with the second pressure-sensitive adhesive layer 13 and exists on the side opposite to the base material layer 15 side is designated as the second protective layer 14. When there are a plurality of layers on the side opposite to the base material layer 15 side with the second pressure-sensitive adhesive layer 13 interposed therebetween, all of them are designated as the second protective layer 14. The second protective layer 14 may include one or more of the following base film, pressure-sensitive adhesive layer, polarizer layer, retardation layer, touch sensor panel, bonding layer, back plate and the like. The second protective layer 14 preferably includes a back plate.

In the laminate, when there are a plurality of structures in which the pressure-sensitive adhesive layer, the coating layer, the thermoplastic resin film, and the pressure-sensitive adhesive layer are in contact with each other in this order, the first protective layer 10 and the first protective layer 10 The pressure-sensitive adhesive layer 11, the intervening coating layer 12, the base material layer 15, the second pressure-sensitive adhesive layer 13, and the second protective layer 14 can be recognized in a plurality of patterns. For example, when the laminate 100 is composed of a front plate / adhesive layer I / coating layer I / base film I / adhesive layer II / coating layer II / base film II / adhesive layer III / back plate (“/”. "" Means that adjacent layers are in contact with each other. The same applies hereinafter.), The first protective layer 10, the first adhesive layer 11, the intervening coating layer 12, the second adhesive layer 13 and the second protective layer 14 are , Can be certified in two patterns. That is, the first protective layer 10 is a front plate, the first pressure-sensitive adhesive layer 11 is the pressure-sensitive adhesive layer I, the intervening coating layer 12 is the coating layer I, and the base material layer 15 is the base film I. It can be determined that the second pressure-sensitive adhesive layer 13 is the pressure-sensitive adhesive layer II and the second protective layer 14 is the coating layer II / base film II / pressure-sensitive adhesive layer III / back plate. On the other hand, the first protective layer 10 is a front plate / adhesive layer I / coating layer I / base film I /, the first adhesive layer 11 is an adhesive layer II, and the intervening coating layer 12 is a coating layer. It can also be determined that the base material layer 15 is the base material film II, the second pressure-sensitive adhesive layer 13 is the pressure-sensitive adhesive layer III, and the second protective layer 14 is the back plate. In such a case, in both certification patterns, the laminate satisfying the formulas (3), (4) and (5) pertaining to the evaluation parameters A1 and A2 is bent when the first protective layer is turned inside. , The generation of cracks in the coating layer is suppressed.

Hereinafter, the layers that can form the laminated body 100 will be described.

(Front plate)
The material and thickness of the front plate are not limited as long as it is a plate-like body capable of transmitting light, and the front plate 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 a touch sensor panel described later. The front plate can constitute the outermost surface of the display device.

The thickness of the front plate may be, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 300 μm or less. In the present invention, the thickness of each layer can be measured according to the thickness measuring method described in Examples described later.

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

The front plate is preferably a film in which a hard coat layer is provided on at least one surface of the base film from the viewpoint of hardness. 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 is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include acrylic resin, silicone resin, polyester resin, urethane resin, amide resin, epoxy resin and the like. The hard coat layer may contain additives to improve hardness. Additives are not limited, and examples thereof include inorganic fine particles, organic fine particles, and mixtures thereof.

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

When the laminate 100 is used in a display device, the front plate not only has a function of protecting the front surface (screen) of the display device (function as a window film), but also functions as a touch sensor, a blue light cut function, and the like. It may have a viewing angle adjusting function or the like.

From the viewpoint of easily forming the laminated body 100 having excellent flexibility, the front plate preferably has a tensile elastic modulus of 4.0 GPa or more at a temperature of 23 ° C., and more preferably 5.0 GPa or more. .. The front plate preferably has a tensile elastic modulus of 20 GPa or less at a temperature of 23 ° C., and more preferably 15 GPa or less, from the viewpoint of easily forming a laminated body 100 having excellent flexibility. The tensile modulus can be measured by the test method described in the Examples column below.

(Base film)
The base film may be composed of, for example, a resin film, preferably a transparent resin film. The resin film may be a long roll-shaped resin film or a single-wafer-shaped resin film. A long roll-shaped resin film is preferable because it can be continuously produced.

Examples of the resin constituting the resin film include polyolefins such as polyethylene, polypropylene, norbornene-based polymer, and cyclic olefin-based resin; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; triacetylcellulose, diacetylcellulose, and the like. Examples thereof include plastics such as cellulose ester such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyether sulfone; polyether ketone; polyphenylene sulfide; polyphenylene oxide; polyamide; polyimide; polyamideimide. Of these, cyclic olefin resins, cellulose esters and polyimides are preferable.

The thickness of the resin film is preferably thin from the viewpoint of thinning the laminate 100, but if it is too thin, it tends to be difficult to secure impact resistance. The thickness of the resin film 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.

A coating layer can be formed on the base film. The base film may have a hard coat layer, an antireflection layer, or an antistatic layer on at least one surface. The base film 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 coating layer is not formed. The base film 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 coating layer is formed. The substrate film may include an adhesive layer for bonding with other layers.

(Adhesive layer)
The pressure-sensitive adhesive layer is a layer that is interposed between the two layers and adheres them, for example, a layer composed of a pressure-sensitive adhesive or an adhesive, or a layer obtained by applying some treatment to the layer. You can. The pressure-sensitive adhesive is also called a pressure-sensitive adhesive. As used herein, the term "adhesive" refers to an adhesive other than an adhesive (pressure sensitive adhesive) and is clearly distinguished from an adhesive. The pressure-sensitive adhesive layer may be one layer or two or more layers, but is preferably one layer. The pressure-sensitive adhesive layer can be formed from the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive layer can be composed of 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, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer containing one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. The base polymer is preferably copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl ( Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meta) acrylate.

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

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with active energy rays such as ultraviolet rays and electron beams, and has adhesiveness even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having the property of being able to adhere to an adherend such as, etc., and being cured by irradiation with active energy rays to adjust the adhesion force. The active energy ray-curable pressure-sensitive adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the cross-linking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer, or the like may be contained.

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

The pressure-sensitive adhesive layer can be formed by applying an organic solvent diluent of the above-mentioned 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 pressure-sensitive adhesive layer is, for example, preferably 1 μm or more and 100 μm or less, more preferably 3 μm or more and 50 μm or less, and may be 20 μm or more.

(Polarizer layer)
Examples of the polarizer layer include a stretched film or a stretched layer on which a dichroic dye is adsorbed, a layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound, and the like. As the dichroic dye, specifically, iodine or a dichroic organic dye is used. For dichroic organic dyes, C.I. I. Included are dichroic direct dyes composed of disuazo compounds such as DIRECT RED 39 and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo.

The polarizer layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound is a composition containing a dichroic dye having a liquid crystal property or a composition containing a dichroic dye and a polymerizable liquid crystal. Examples thereof include a polarizer layer containing a cured product of a polymerizable liquid crystal compound such as a layer obtained by applying and curing an object.
A polarizer layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound is preferable because there is no limitation in the bending direction as compared with a stretched film or a stretched layer on which a dichroic dye is adsorbed.

((Stretched film or polarizer layer which is a stretched layer))
The polarizer layer, which is a stretched film on which a bicolor dye is adsorbed, is usually bicolorized by a step of uniaxially stretching the polyvinyl alcohol-based resin film and dyeing the polyvinyl alcohol-based resin film with the bicolor dye. It can be produced through a step of adsorbing a dye, a step of treating a polyvinyl alcohol-based resin film on which a bicolor dye is adsorbed with an aqueous boric acid solution, and a step of washing with water after the treatment with the aqueous boric acid solution.
The thickness of the polarizer layer is, for example, 2 μm or more and 40 μm or less. The thickness of the polarizer layer may be 5 μm or more, 20 μm or less, further 15 μm or less, and further 10 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 degree of saponification of the polyvinyl alcohol-based resin is usually about 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 or more and 10000 or less, preferably 1500 or more and 5000 or less.

The polarizing element layer, which is a stretched layer on which a dichroic dye is adsorbed, is usually a step of applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, a step of uniaxially stretching the obtained laminated film, and a uniaxial A step of dyeing the polyvinyl alcohol-based resin layer of the stretched laminated film with a dichroic dye to adsorb the dichroic dye to form a polarizer layer, and boric acid on the film on which the dichroic dye is adsorbed. It can be produced through a step of treating with an aqueous 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 layer. 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 stretched film or the polarizer layer, which is 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 layer 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 bonded to the polarizer layer by using, for example, an adhesive layer.

((Polarizer layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound))
The polarizer layer formed by applying and curing a composition containing a dichroic dye and a polymerizable compound includes a composition containing a dichroic dye having a liquid crystal property or a dichroic dye and a polymerizable liquid crystal. Examples thereof include a polarizer layer containing a cured product of a polymerizable liquid crystal compound, such as a layer obtained by applying a composition containing the above to a substrate film and curing the composition.

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

The polarizer layer obtained by applying and curing the composition containing the dichroic dye and the polymerizable compound may be incorporated into the optical laminate in the form in which a thermoplastic resin film is bonded to one side or both sides thereof. .. As the thermoplastic resin film, the same one as the thermoplastic resin film that can be used for the stretched film or the polarizer layer that is the stretched layer can be used. The thermoplastic resin film can be bonded to the polarizer layer using, for example, an adhesive layer.

The thickness of the polarizer layer obtained by applying and curing the composition containing the dichroic dye and the polymerizable compound is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 5 μm or less. Is.

The intervening coating layer 12 can include, for example, a polarizer layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound. As a structure including the intervening coating layer 12 and the base material layer 15 in contact with each other, a structure in which a polarizer layer formed by applying a composition containing a dichroic dye and a polymerizable compound on a base material film and curing the composition is formed. Examples thereof include a structure in which a thermoplastic resin film is bonded to a polarizer layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound. When the intervening coating layer 12 contains a polarizer layer obtained by applying and curing a composition containing a dichroic dye and a polymerizable compound, the intervening coating layer 12 is an alignment film or a protective layer (specifically, a kind of coating layer). Examples thereof include a hard coat (OC) layer and an overcoat (HC) layer).

(Phase difference layer)
The laminated body 100 can include one layer or two or more retardation layers. The retardation layer is usually arranged between the polarizer layer and the back plate. The retardation layer is formed through a first pressure-sensitive adhesive layer 11, a second pressure-sensitive adhesive layer 13, or a layer composed of a pressure-sensitive adhesive or an adhesive other than these layers (hereinafter, also referred to as a bonding layer). (Including other retardation layers.) Can be laminated on top.

The retardation layer can be a positive A plate such as a λ / 4 plate or a λ / 2 plate, and a positive C plate. The retardation layer may be a resin film exemplified as the material of the protective film described above, or may be a layer formed by curing a polymerizable liquid crystal compound. The retardation layer may further include an alignment film and a base film. The thickness of the retardation layer is, for example, 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 8 μm or less, and more preferably 1 μm or more and 6 μm or less.

The retardation layer formed by curing the polymerizable liquid crystal compound can be formed by applying a composition containing the polymerizable liquid crystal compound to a base film and curing the composition. An orientation layer may be formed between the base film and the coating layer. The material and thickness of the base film may be the same as the material and thickness of the thermoplastic resin film described above.
The retardation layer formed by curing the polymerizable liquid crystal compound may be incorporated into the laminate 100 in the form of having an alignment layer and / or a base film.

The intervening coating layer 12 can include, for example, a retardation layer obtained by curing a polymerizable liquid crystal compound. Examples of the structure including the intervening coating layer 12 and the base material layer 15 in contact with each other include a structure in which a retardation layer formed by curing a polymerizable liquid crystal compound is formed on the base material film. When the intervening coating layer 12 includes a retardation layer formed by curing a polymerizable liquid crystal compound, the intervening coating layer 12 is an alignment film or a protective layer (specifically, a hard coat layer or an overcoat layer) which is a kind of coating layer. ) And the like may be further included.

(Touch sensor panel)
As long as the touch sensor panel is a sensor that can detect the touched position, the detection method is not limited, and the resistance film method, capacitance method, optical sensor method, ultrasonic method, electromagnetic induction coupling method, etc. A touch sensor panel such as a surface acoustic wave method is exemplified. Among them, the capacitance type touch sensor panel is preferably used in terms of low cost, fast reaction speed, and thin film formation. The touch sensor panel may include an adhesive layer, a separation layer, a protective layer, and the like between the transparent conductive layer and the base film that supports the transparent conductive layer. Examples of the adhesive layer include an adhesive layer and an adhesive layer.
Examples of the base film that supports the transparent conductive layer include a base film in which a transparent conductive layer is vapor-deposited on one surface, a base film in which the transparent conductive layer is transferred via an adhesive layer, and the like.

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

The transparent conductive layer may be a transparent conductive layer made of a metal oxide such as ITO, or may be a metal layer made of a metal such as aluminum, copper, silver, gold, or an alloy thereof. The transparent electrode layer is formed by a coating method such as a sputtering method, a printing method, or a thin film deposition method. A photosensitive resist is formed on the transparent electrode layer, and then an electrode pattern layer is formed by photolithography. As the photosensitive resist, a negative type photosensitive resist or a positive type photosensitive resist is used, and the photosensitive resist may remain or be removed after patterning. When the film is formed by the sputtering method, a mask having an electrode pattern shape can be arranged and sputtering can be performed to form an electrode pattern layer.

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

The protective layer can be provided in contact with the transparent conductive layer to protect the conductive layer. The protective layer contains at least one of an organic insulating film and an inorganic insulating film, and these films can be formed by a coating method such as a spin coating method, a sputtering method, or a vapor deposition method.

The insulating layer can be formed from, for example, an inorganic insulating substance such as silicon oxide or a transparent organic substance such as an acrylic resin. The insulating layer can be formed by heat curing, UV curing, heat drying, vacuum drying, or the like after coating by a known coating method.

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

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

The touch sensor panel can be manufactured as follows, for example. In the first method, the base film is first laminated on the substrate via the adhesive layer. A transparent conductive layer patterned by photolithography is formed on the base film. By applying heat, the substrate and the base film are separated to obtain a touch sensor panel composed of the transparent conductive layer and the base film. The substrate is not particularly limited as long as it maintains flatness and has heat resistance, but is preferably a glass substrate.

In the second method, a material for forming a separation layer is first applied on a substrate to form a separation layer. If necessary, a protective layer is formed on the separation layer by coating. A protective layer may be formed in the portion where the pad pattern layer is formed so that the protective layer is not formed. A transparent conductive layer patterned by photolithography is formed on the separation layer (or protective layer). An insulating layer is formed on the transparent conductive layer so as to fill the electrode pattern layer. A protective film is laminated on the insulating layer with a peelable adhesive, and the insulating layer to the separating layer are transferred to separate the substrate. By peeling off the peelable protective film, a touch sensor panel having an insulating layer / a transparent conductive layer / (protective layer) / a separating layer in this order can be obtained.

When the base film is included, the thickness of the touch sensor panel may be, for example, 5 μm or more and 2000 μm or less, and may be 5 μm or more and 100 μm or less.

When the base film is not included, the thickness of the touch sensor panel is, for example, 0.5 μm or more and 10 μm or less, preferably 5 μm or less.

The intervening coating layer 12 can include, for example, a touch sensor panel manufactured by the second method. As a structure including the intervening coating layer 12 and the base material layer 15 in contact with each other, the touch sensor panel and the base material film produced by the first method and the touch sensor panel produced by the second method are attached with an adhesive. A combined structure can be mentioned.

(Lated layer)
The bonding layer is a layer composed of an adhesive or an adhesive. The bonding layer can be, for example, a layer for bonding the front plate and the touch sensor panel, a layer for bonding the front plate and the polarizing plate, and a layer for bonding the polarizing plate and the touch sensor panel. The pressure-sensitive adhesive constituting the bonding layer may be the same as that exemplified for the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer, or other pressure-sensitive adhesives such as (meth) acrylic pressure-sensitive adhesive and styrene-based adhesive. It may be a pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, an epoxy-based copolymer pressure-sensitive adhesive, or the like.
The laminate 100 may include one laminating layer or two or more laminating layers. When the laminate 100 includes a plurality of bonded layers, the plurality of bonded layers may be the same as each other or may be different from each other.

As the adhesive constituting the bonded layer, for example, one or two or more of water-based adhesives, active energy ray-curable adhesives, adhesives and the like can be combined to form the adhesive. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that cures by irradiating with active energy rays such as ultraviolet rays, and includes, for example, a polymerizable compound and a photopolymerizable initiator, a photoreactive resin, and the like. Examples thereof include those containing a binder resin and a photoreactive cross-linking agent. Examples of the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable acrylic monomer, and a photocurable urethane monomer, and oligomers derived from these monomers. Examples of the photopolymerization initiator include substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals by irradiating them with active energy rays such as ultraviolet rays.

The thickness of the bonded layer may be, for example, 1 μm or more, preferably 1 μm or more and 25 μm or less, more preferably 2 μm or more and 15 μm or less, and further preferably 2.5 μm or more and 5 μm or less.

(Back plate)
As the back plate, a plate-like body capable of transmitting light, a component used in a normal display device, or the like can be used.

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

The plate-like body used for the back plate may be composed of only one layer, may be composed of two or more layers, and the plate-like body described in the above-mentioned front plate may be used as an example. it can.

Examples of components used in a normal display device used for a back plate include a touch sensor panel, an organic EL display element, and the like. Examples of the stacking order of the components in the display device include a window film / circular polarizing plate / touch sensor panel / organic EL display element, a window film / touch sensor panel / circular polarizing plate / organic EL display element, and the like.

From the viewpoint that the back plate can easily form the laminated body 100 having excellent flexibility, the tensile elastic modulus at a temperature of 23 ° C. is preferably 4.0 GPa or more, and more preferably 4.5 GPa or more. .. From the viewpoint of easily forming the laminated body 100 having excellent flexibility, the back plate preferably has a tensile elastic modulus of 20 GPa or less at a temperature of 23 ° C., and more preferably 15 GPa or less. The tensile modulus can be measured by the test method described in the Examples column below.

[Manufacturing method of laminate]
The laminate 100 can be manufactured by a method including a step of adhering layers constituting the laminate 100 to each other 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 corona treatment in order to improve the adhesion. Is preferable.

<Display device>
The display device according to the present invention includes the laminate 100 according to the present invention. The display device is not particularly limited, and examples thereof include an image display device such as an organic EL display device, an inorganic EL display device, a liquid crystal display device, and an electroluminescent display device. The display device may have a touch panel function. The optical laminate is suitable for a flexible display device that can be bent or bent.

In the display device, the optical laminate is arranged on the visible side of the display element of the display device with the front plate facing the outside (the side opposite to the display element side, that is, the visual recognition side).

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

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

<Laminated body consisting of "base film / polarizer layer">
(Base film)
As a base film, a cycloolefin polymer (COP) film (ZF-14, manufactured by Nippon Zeon Corporation, thickness 23 μm) was prepared.

(Polarizer layer)
Roll a long polyvinyl alcohol (PVA) raw film with a thickness of 30 μm [trade name “Kuraray Poval Film VF-PE # 3000” manufactured by Kuraray Co., Ltd., average degree of polymerization 2400, saponification degree 99.9 mol% or more] The film was continuously conveyed while being unwound from, and immersed in a swelling bath made of pure water at 20 ° C. with a residence time of 31 seconds (swelling step). Then, the film pulled out from the swelling bath was immersed in a dyeing bath containing iodine having a potassium iodide / water ratio of 2/100 (weight ratio) at 30 ° C. for a residence time of 122 seconds (dyeing step). Next, the film drawn from the dyeing bath was immersed in a cross-linked bath at 56 ° C. in which potassium iodide / boric acid / water was 12 / 4.1 / 100 (weight ratio) for a residence time of 70 seconds, followed by iodine. Potassium iodide / boric acid / water was immersed in a cross-linking bath at 40 ° C. of 9 / 2.9 / 100 (weight ratio) with a residence time of 13 seconds (cross-linking step). In the dyeing step and the cross-linking step, longitudinal uniaxial stretching was performed by stretching between rolls in a bath. The total draw ratio based on the raw film was 5.4 times. Next, the film drawn from the crosslinked bath was immersed in a washing bath made of pure water at 5 ° C. for a residence time of 3 seconds (washing step), and then introduced into a first heating furnace capable of controlling humidity. A high-temperature and high-humidity treatment was performed with a residence time of 190 seconds (high-temperature and high-humidity treatment step) to obtain a polarizer layer (PVA) having a thickness of 12.1 μm.

(Adhesive composition)
Water: 100 parts by weight, polyvinyl alcohol resin powder (manufactured by Kuraray Co., Ltd., average degree of polymerization 18,000, trade name: KL-318): 3 parts by weight, polyamide epoxy resin (crosslinking agent, manufactured by Sumika Chemtex Co., Ltd., product name: SR650 (30)): 1.5 parts by weight was mixed to obtain an adhesive composition.

(Preparation of a laminate composed of "base film / polarizer layer")
The polarizer layer and the base film were subjected to corona treatment. The conditions for corona treatment were an output of 0.3 kW and a processing speed of 3 m / min. Then, these were bonded together via an adhesive composition and dried at 60 ° C. for 2 minutes to obtain a laminate composed of a "base film / polarizer layer".

<Laminated body consisting of "base film / second alignment film / retardation layer">
(Base film)
A polyethylene terephthalate (PET) film (thickness 100 μm) was prepared as a base film.

(Composition for forming an alignment film)
Polymer 1 is a polymer having a photoreactive group consisting of the following structural units.

From the GPC measurement, the molecular weight of the obtained polymer 1 showed a number average molecular weight of 28200 and Mw / Mn1.82, and the monomer content was 0.5%.
A solution prepared by dissolving polymer 1 in cyclopentanone at a concentration of 5% by mass was used as a composition for forming an alignment film.

(Composition for forming a retardation layer)
Each of the components shown below was mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a retardation layer.
Compound b-1 represented by the following formula: 80 parts by mass

Compound b-2: 20 parts by mass represented by the following formula

Polymerization initiator (Irgacure369, 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one, manufactured by BASF Japan Ltd.): 6 parts by mass leveling agent (BYK-361N, polyacrylate compound, BYK) -Chemie): 0.1 parts by mass Solvent (cyclopentanone): 400 parts by mass

(Preparation of a laminate composed of "base film / second alignment film / retardation layer")
The composition for forming an alignment film was applied onto the base film by the bar coating method, and dried by heating in a drying oven at 80 ° C. for 1 minute. The obtained dry film was subjected to polarized UV irradiation treatment to form a second alignment film. The polarized UV treatment was carried out under the condition that the integrated light amount measured at a wavelength of 365 nm was 100 mJ / cm ² using the above UV irradiation device. Further, the polarization direction of the polarized UV was set to 45 ° with respect to the absorption axis of the polarizing layer. In this way, a laminate made of a "base film / second alignment film" was obtained. The thickness of the second alignment film was 100 nm.

The composition for forming a retardation layer is applied to the second alignment film of the laminate composed of the "base film / second alignment film" by the bar coating method, and after heating and drying in a drying oven at 120 ° C. for 1 minute, It was cooled to room temperature. A retardation layer was formed by irradiating the obtained dry film with ultraviolet rays having an integrated light intensity of 1000 mJ / cm ² (365 nm standard) using the above UV irradiation device. The thickness of the obtained retardation layer was measured with a laser microscope (OLS3000 manufactured by Olympus Corporation) and found to be 2.0 μm. The retardation layer was a λ / 4 plate showing a retardation value of λ / 4 in the in-plane direction. In this way, a laminate composed of "base film / second alignment film / retardation layer" was obtained.

<Phase difference film>
As the retardation film, a 1/4 wave plate (“Zeonoa film”, Nippon Zeon Corporation) having a thickness of 20 μm, which is a uniaxially stretched film of a cyclic olefin resin, was prepared.

<Laminated body consisting of "touch sensor panel / base film">
An organic polymer film was applied onto the substrate to form a separation layer. An organic insulating film was applied on the separation layer to form a protective layer. An ITO transparent electrode layer was formed on the protective layer as a transparent electrode layer, and a photosensitive resist was formed on the ITO transparent electrode layer. On it, an electrode pattern layer was formed by selectively patterning by photolithography. The photosensitive resist was removed from the electrode pattern layer. An insulating layer was formed on the coating layer to obtain a touch sensor panel. The thickness of the touch sensor panel was 4.6 μm. A base film made of cycloolefin polymer (COP) is attached to the upper part of the insulating layer of the touch sensor panel via an adhesive layer, and the separation layer is peeled off from the substrate to form a "touch sensor panel / base film". A laminate was obtained.

<Adhesive sheet>
(Adhesive Composition A)
81.8 parts by mass of acetone, 98.6 parts by mass of butyl acrylate, 0.4 parts by mass of acrylic acid, and 2-hydroxyethyl acrylate 1 in a reactor equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer. A mixed solution of 0.0 parts by mass was charged, and the internal temperature was raised to 55 ° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Then, a total amount of a solution prepared by dissolving 0.14 parts by mass of azobisisobutyronitrile (polymerization initiator) in 10 parts by mass of acetone was added. One hour after the addition of the polymerization initiator, the internal temperature was 54 to 54 while continuously adding acetone to the reactor at an addition rate of 17.3 parts by mass / hr so that the concentration of the acrylic resin excluding the monomer became 35%. The temperature was kept at 56 ° C. for 12 hours, and finally ethyl acetate was added to adjust the acrylic resin solution A so that the concentration of the acrylic resin was 20%.

Non-volatile content of acrylic resin solution A Acrylic resin: 100 parts by mass Isocyanate compound: 0.4 parts by mass Silane compound: 0.5 parts by mass was mixed. Ethyl acetate was added so that the total solid content concentration became 10% to obtain a pressure-sensitive adhesive composition A.
As the isocyanate-based compound, an ethyl acetate solution (solid content concentration 75%) of a trimethylolpropane adduct of tolylene diisocyanate (“Coronate L” manufactured by Tosoh Corporation) was used. As the silane compound, 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM403") was used.

(Adhesive sheets "A40", "A25", "A15")
The obtained pressure-sensitive adhesive composition A is applied to the release-treated surface of a polyethylene terephthalate film (light release film B, thickness 38 μm) that has been release-treated so that the thickness after drying is 40 μm using an applicator. Then, it was dried at 100 ° C. for 1 minute to obtain a film having an adhesive layer. Then, another release-treated polyethylene terephthalate film (heavy release film A, thickness 38 μm) was laminated on 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 to produce an adhesive sheet "A40".

The adhesive sheet "A25" was produced in the same manner as "A40" except that it was applied so that the thickness after drying was 25 μm.

The adhesive sheet "A15" was produced in the same manner as "A40" except that it was applied so that the thickness after drying was 15 μm.

(Adhesive Composition B)
Same as acrylic resin solution A except that the monomer composition was changed to 78.6 parts of butyl acrylate, 20 parts of methyl methacrylate, 0.4 parts of acrylic acid, and 1.0 part of 2-hydroxyethyl acrylate. Acrylic resin solution B was obtained.

Non-volatile content of acrylic resin solution B Acrylic resin: 100 parts by mass Isocyanate compound: 0.5 parts by mass Silane compound: 0.5 parts by mass was mixed. Ethyl acetate was added so that the total solid content concentration became 10% to obtain a pressure-sensitive adhesive composition B. As the isocyanate-based compound and the silane-based compound, the same ones used in the pressure-sensitive adhesive composition A were used.

(Adhesive sheets "B40", "B25", "B15")
Adhesive sheets "B40", "B25", "B15" having a thickness of the adhesive layer of 40 μm, 25 μm, and 15 μm after drying in the same manner as the adhesive sheet “A40” except that the adhesive composition B is used. Was produced.

(Adhesive Composition C)
Same as acrylic resin solution A except that the monomer composition was changed to 61.0 parts of butyl acrylate, 37 parts of methyl methacrylate, 1.0 part of acrylic acid, and 1.0 part of 2-hydroxyethyl acrylate. Acrylic resin solution C was obtained.

Non-volatile content of acrylic resin solution C Acrylic resin: 100 parts by mass Isocyanate compound: 3.0 parts by mass Silane compound: 0.5 parts by mass was mixed. Ethyl acetate was added so that the total solid content concentration became 10% to obtain a pressure-sensitive adhesive composition C. As the isocyanate-based compound and the silane-based compound, the same ones used in the pressure-sensitive adhesive composition A were used.

(Adhesive sheets "C25", "C15", "C05")
Adhesive sheets "C25", "C15", "C05" having a thickness of the adhesive layer of 25 μm, 15 μm, and 5 μm after drying in the same manner as the adhesive sheet “A40” except that the adhesive composition C is used. Was produced.

For the prepared pressure-sensitive adhesive layer, the storage elastic modulus and the layer thickness were measured according to the following, and the evaluation parameter A (storage elastic modulus / layer thickness) was determined. Evaluation parameter A is a general term for A1 and A2. The results are shown in Table 1.

[Layer thickness]
The thickness of the pressure-sensitive adhesive layer was measured using a contact-type film thickness measuring device (“MS-5C” manufactured by Nikon Corporation). However, the polarizer layer and the alignment film were measured using a laser microscope (“OLS3000” manufactured by Olympus Corporation).

[Method for measuring storage elastic modulus]
The storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25 ° C. was measured using a viscoelasticity measuring device (MCR-301, Antonio Par). Each adhesive sheet having a thickness of 25 μm was cut into a width of 30 mm and a length of 30 mm. After peeling off the release film, laminating a plurality of sheets so as to have a thickness of 150 μm and joining them to a glass plate, the frequency is 1.0 Hz and the deformation amount is 1% in the temperature range of -20 ° C to 100 ° C in a state of being adhered to the measurement chip. The measurement was carried out under the condition of a temperature rising rate of 5 ° C./min, and the storage elastic modulus at a temperature of 25 ° C. was confirmed.

<Front plate>
As a window film as a front plate, a polyimide film (HC-PI film, overall thickness: 70 μm, tensile elastic modulus 5.6 GPa) having a hard coat layer on one side was prepared.

<Back plate>
As a back plate, a polyethylene terephthalate (PET) substrate (thickness 38 μm, tensile elastic modulus 4.5 GPa) was prepared.

[Tensile modulus measurement method]
The tensile elastic modulus of the front plate and the back plate was measured as follows. A rectangular small piece having a long side of 110 mm and a short side of 10 mm was cut out from the front plate or the back plate using a super cutter. Next, the upper and lower grippers of a tensile tester (manufactured by Shimadzu Corporation, Autograph AG-Xplus tester) sandwich both ends of the measurement sample in the long side direction so that the gap between the grippers is 5 cm, and the temperature is 23 ° C. In an environment with a relative humidity of 55%, the measurement sample was pulled in the length direction of the measurement sample at a tensile speed of 4 mm / min, and from the slope of a straight line between 20 and 40 MPa in the obtained stress-strain curve, 23 ° C., relative The tensile elastic modulus at a humidity of 55% was calculated. At this time, the thickness for calculating the stress was measured by the method described above.

<Manufacturing of the laminate of Example 1-1>
The light release film B was peeled off from the pressure-sensitive adhesive sheet "A25" and bonded to the polarizer layer side of the laminate composed of the "base film / polarizer layer" to obtain the laminate A1. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate A1 and bonded to the retardation film which is a retardation layer to obtain a laminate A2. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled off from the adhesive sheet "B15" and bonded to the retardation layer side of the laminate A2 to obtain the laminate A3. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled off from the adhesive sheet "A25" and bonded to the side of the front plate having no hard coat layer to obtain a laminated body A4. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate A4 and bonded to the base film used for forming the polarizer layer of the laminate A3 to obtain the laminate A5. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate A5 and bonded to the touch sensor panel side of the laminate made of the "touch sensor panel / base film" to obtain the laminate A6. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled off from the adhesive sheet "C05" and attached to the base film side attached to the touch sensor panel of the laminate A6 to obtain the laminate A7. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate A7 and bonded to the back plate to obtain the laminate of Example 1-1 as shown in FIG. In FIG. 2, the first protective layer 10 is from the front plate to the retardation layer, the adhesive layer under the retardation layer is the first adhesive layer 11, the touch sensor panel is the intervening coating layer 12, and the base material under the touch sensor panel. The film is the base material layer 15, the pressure-sensitive adhesive layer under the touch sensor panel / base material film is the second pressure-sensitive adhesive layer 13, and the back plate is the second protective layer 14.

<Manufacturing of Laminated Body of Example 1-2>
A laminate of Example 1-2 was obtained in the same manner as in Example 1-1 except that "A15" was used instead of the adhesive sheet "B15" and "B25" was used instead of "C05".

<Manufacturing of Laminated Body of Comparative Example 1-1>
A laminate of Comparative Example 1-1 was obtained in the same manner as in Example 1-1 except that "C05" was used instead of the adhesive sheet "B15" and "B15" was used instead of "C05".

<Manufacturing of laminated body of Comparative Example 1-2>
A laminate of Comparative Example 1-2 was obtained in the same manner as in Example 1-1 except that "C15" was used instead of the adhesive sheet "B15".

Table 2 summarizes the pressure-sensitive adhesive layers used in the laminates of Examples 1-1 and 1-2 and Comparative Examples 1-1 and 1-2. The values of "A1 + A2", "A2-A1", and "A1" are as shown in Table 2.
Table 2 shows the results of the flexibility test of the laminated body.

[Flexibility test]
The laminate was subjected to an evaluation test for confirming the flexibility using a bending evaluation facility (STS-VRT-500 manufactured by Science Town). FIG. 4 is a diagram schematically showing the method of this evaluation test. As shown in FIG. 4, two individually movable mounting tables 501 and 502 are arranged so that the gap C is 2 mm (bending radius 1 mm), and the center in the width direction is located at the center of the gap C. And the laminated body was fixedly arranged so that the first protective layer was located on the upper side (FIG. 4 (a)). Then, the two mounting tables 501 and 502 were rotated 90 degrees upward with the positions P1 and P2 as the centers of the rotation axes, and a bending force was applied to the region of the laminated body corresponding to the gap C of the mounting tables (FIG. 4 (b)). After that, the two mounting tables 501 and 502 were returned to their original positions (FIG. 4 (a)). After completing the above series of operations, the number of times the bending force was applied was counted as one. After repeating this at a temperature of 25 ° C., it was confirmed whether or not cracks were generated in the coating layer in the region corresponding to the gap C of the mounting tables 501 and 502 of the laminated body.
The moving speed of the mounting tables 501 and 502 and the pace of application of the bending force were set to the same conditions in the evaluation test for all the laminated bodies.
A: No cracks occurred even when the number of times the bending force was applied reached 300,000.
B: A crack occurred when the number of times the bending force was applied was 200,000 or more and less than 300,000.
C: A crack occurred when the number of times the bending force was applied was 100,000 or more and less than 200,000.
D: A crack occurred when the number of times the bending force was applied was less than 100,000.

In Table 2, regarding "A1 + A2", "A1 + A2 ≤ 130" is "A", "130 <A1 + A2 ≤ 230" is "B", "230 <A1 + A2 ≤ 260" is "C", and "260 <A1 + A2" is " It was set as "D". Regarding "A2-A1", "100≤A2-A1" is "A", "0≤A2-A1 <100" is "B", "-100≤A2-A1 <0" is "C", and "A2". -A1 <-100 "was set to" D ". Regarding "A1", "A1 ≤ 5" was set to "A", "5 <A1 ≤ 20" was set to "B", "20 <A1 ≤ 60" was set to "C", and "60 <A1" was set to "D". .. The same applies to the table below.

In the laminates of Examples 1-1 and 1-2, "A1 + A2" was 230 or less, "A2-A1" was 0 or more, and "A1" was 20 or less. In these laminates, the occurrence of cracks in the coating layer was suppressed. In the laminate of Example 1-2 in which "A1 + A2" was smaller than 130, "A2-A1" was 0 or more, and "A1" was 5 or less, the occurrence of cracks was further suppressed. On the other hand, although the same coating layer and base material layer are used, "A2-A1" is smaller than 0 and "A1" is larger than 20, the laminate of Comparative Example 1-1, and "A1 + A2" is more than 230. The occurrence of cracks was not suppressed in the laminated body of Comparative Example 1-2, which was large and had "A1" larger than 20.

<Manufacturing of the laminate of Example 2-1>
The light release film B was peeled off from the adhesive sheet "A25" and bonded to the polarizer layer side of the laminate composed of the "base film / polarizer layer" to obtain the laminate B1. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate B1 and bonded to the retardation layer side of the laminate composed of the "base film / second alignment film / retardation layer" to obtain the laminate B2. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled from the adhesive sheet "B15", and the base film used for forming the retardation layer and the second alignment film were bonded to the peeled surface from the laminate B2 to obtain the laminate B3. .. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled off from the adhesive sheet "A25" and bonded to the side of the front plate having no hard coat layer to obtain a laminated body B4. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate B4 and bonded to the base film used for forming the polarizer layer of the laminate A3 to obtain the laminate B5. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate B5 and bonded to the touch sensor panel side of the laminate made of the "touch sensor panel / base film" to obtain the laminate B6. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The light release film B was peeled off from the adhesive sheet "C05" and attached to the base film attached to the touch sensor panel of the laminate B6 to obtain the laminate B7. The bonded surface was previously subjected to double-sided corona treatment (output 0.3 kW, speed 3 m / min).

The heavy release film A was peeled from the laminate B7 and bonded to the back plate to obtain the laminate of Example 2-1 as shown in FIG. In FIG. 3, the first protective layer 10 is from the front plate to the retardation layer, the pressure-sensitive adhesive layer under the retardation layer is the first pressure-sensitive adhesive layer 11, the touch sensor panel is the intervening coating layer 12, and the base material under the touch sensor panel. The film is the base material layer 15, the pressure-sensitive adhesive layer under the touch sensor panel / base material film is the second pressure-sensitive adhesive layer 13, and the back plate is the second protective layer 14.

<Manufacturing of Laminated Body of Example 2-2>
A laminate of Example 2-2 was obtained in the same manner as in Example 2-1 except that "A15" was used instead of the adhesive sheet "B15" and "B25" was used instead of "C05".

<Manufacturing of Laminated Body of Comparative Example 2-1>
A laminate of Comparative Example 2-1 was obtained in the same manner as in Example 2-1 except that "C05" was used instead of the adhesive sheet "B15" and "B15" was used instead of "C05".

<Manufacturing of laminated body of Comparative Example 2-2>
A laminate of Comparative Example 2-2 was obtained in the same manner as in Example 2-1 except that "C15" was used instead of the adhesive sheet "B15".

Table 3 summarizes the pressure-sensitive adhesive layers used in the laminates of Examples 2-1 and 2-2 and Comparative Examples 2-1 and 2-2. The values of "A1 + A2", "A2-A1", and "A1" are as shown in Table 3.
Table 3 shows the results of the flexibility test of the laminated body.

In the laminates of Examples 2-1 and 2-2, "A1 + A2" was 230 or less, "A2-A1" was 0 or more, and "A1" was 20 or less. In these laminates, the generation of cracks was suppressed in the coating layer. In the laminate of Example 2-2 in which "A1 + A2" was smaller than 130, "A2-A1" was 0 or more, and "A1" was 5 or less, the occurrence of cracks was further suppressed. On the other hand, although the same coating layer and base material layer are used, "A2-A1" is smaller than 0 and "A1" is larger than 20, the laminate of Comparative Example 2-1 and "A1 + A2" are more than 230. The occurrence of cracks was not suppressed in the laminated body of Comparative Example 2-2, which was large and had "A1" larger than 20.

100 laminate, 10 first protective layer, 11 first adhesive layer, 12 intervening coating layer, 13 second adhesive layer, 14 second protective layer, 15 base material layer, 501, 502 stage 1 front plate, 2 adhesive Agent layer, 3 base film, 4 polarizer layer, 5 retardation layer, 6 back plate, 7 first alignment film, 8 protective layer (OC layer), 9 protective layer (HC layer), 0 touch sensor panel

Claims

A laminate including a first protective layer, a first pressure-sensitive adhesive layer, an intervening coating layer, a base material layer, a second pressure-sensitive adhesive layer, and a second protective layer in this order.
Each layer is in contact with each other
The storage elastic modulus of the first pressure-sensitive adhesive layer at a temperature of 25 ° C. is G'1 [kPa], and the storage elastic modulus of the second pressure-sensitive adhesive layer at a temperature of 25 ° C. is G'2 [kPa]. When the thickness of the agent layer is a1 [μm] and the thickness of the second pressure-sensitive adhesive layer is a2 [μm], the following formulas (1) and (2):
A1 = G'1 / a1 (1)
A2 = G'2 / a2 (2)
The evaluation parameters A1 and A2 represented by are expressed by the following equations (3), (4) and (5):
A1 + A2 ≤ 230 (3)
A2-A1 ≧ 0 (4)
A1 ≤ 20 (5)
A laminate that meets the requirements.
The laminate according to claim 1, wherein the first protective layer includes a window film having a tensile elastic modulus of 4.0 GPa or more.
The laminate according to claim 1 or 2, wherein the second protective layer includes a back plate having a tensile elastic modulus of 4.0 GPa or more.
The laminate according to any one of claims 1 to 3, wherein the intervening coating layer is composed of one or more layers, and the thickness of each layer is 5 μm or less.
The laminate according to any one of claims 1 to 4, wherein the intervening coating layer includes a polarizer layer, a retardation layer, or a touch sensor panel.
The laminate according to any one of claims 1 to 5, wherein the G'1 and the G'2 are each 10,000 kPa or less.
A display device including the laminate according to any one of claims 1 to 6.