CN116893467A

CN116893467A - Laminate and image display device

Info

Publication number: CN116893467A
Application number: CN202310354781.3A
Authority: CN
Inventors: 柳智熙; 张柱烈
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2022-04-07
Filing date: 2023-04-04
Publication date: 2023-10-17
Also published as: JP2023154554A; KR20230144460A

Abstract

The present invention provides a laminate which comprises a front panel having ultra-thin glass, an adhesive layer, and a polarizing film, and which has improved handleability and improved bendability. The laminate comprises a front panel, an adhesive layer, and a polarizing film, wherein the front panel comprises ultra-thin glass and a hard coat layer, the adhesive layer has a storage modulus of 0.2MPa or less at 25 ℃, and the polarizing film is a laminate comprising a liquid crystal cured layer containing a cured product of a polymerizable liquid crystal compound.

Description

Laminate and image display device

Technical Field

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

Background

Patent document 1 proposes a glass substrate laminate in which a hard coat layer is provided on a thin glass as a flexible glass substrate for a window for a flexible display.

Prior art literature

Patent literature

[ patent document 1 ] Korean patent publication No. 10-2276160

Disclosure of Invention

When the front panel having the ultra-thin glass is attached to the optical member and when the image display device is bent after the front panel is mounted in the image display device, cracks may be easily generated.

The present invention provides a laminate comprising a front panel having ultra-thin glass, an adhesive layer, and a polarizing film, wherein the laminate has improved handleability and improved bendability.

The invention provides a laminate and an image display device.

[1] A laminate comprising a front panel, an adhesive layer and a polarizing film in this order,

the front panel comprises ultra-thin glass and a hard coat layer,

the adhesive layer has a storage modulus of 0.2MPa or less at a temperature of 25 ℃,

the polarizing film is composed of a liquid crystal cured layer containing a cured product of a polymerizable liquid crystal compound.

[2] The laminate according to [1], wherein the thickness of the ultra-thin glass is 50 μm or less.

[3] The laminate according to [1], wherein the hard coat layer has a thickness of 10 μm or more.

[4] The laminate according to [2], wherein the hard coat layer has a thickness of 10 μm or more.

[5] The laminate according to [1] to [4], wherein the adhesive layer has a storage modulus of 0.01MPa or more at a temperature of 25 ℃.

[6] The laminate according to any one of [1] to [4], wherein the thickness of the adhesive layer is 30 μm or less.

[7] The laminate according to [5], wherein the thickness of the adhesive layer is 30 μm or less.

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

[9] An image display device comprising the laminate of [5 ].

[10] An image display device comprising the laminate of [6 ].

[11] An image display device comprising the laminate of [7 ].

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

[a] A laminate comprising a front panel, an adhesive layer and a polarizing film in this order,

the front panel comprises ultra-thin glass and a hard coat layer,

[b] The laminate according to [ a ], wherein the thickness of the ultra-thin glass is 50 μm or less.

[c] The laminate according to [ a ] or [ b ], wherein the hard coat layer has a thickness of 10 μm or more.

[d] The laminate according to any one of [ a ] to [ c ], wherein the adhesive layer has a storage modulus of 0.01MPa or more at a temperature of 25 ℃.

[e] The laminate according to any one of [ a ] to [ d ], wherein the thickness of the adhesive layer is 30 μm or less.

[f] An image display device comprising the laminate of any one of [ a ] to [ e ].

According to the present invention, a laminate comprising a front panel having ultra-thin glass, an adhesive layer, and a polarizing film, having improved handleability and improved bendability can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of a layer structure of a laminate of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the layer structure of the laminate of the present invention.

Fig. 3 is a schematic cross-sectional view showing another example of the layer structure of the laminate of the present invention.

Fig. 4 is a schematic diagram illustrating a bending test method.

Detailed Description

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 of each component shown in the drawings is not necessarily identical to the scale of the actual component, and is appropriately adjusted and displayed for easy understanding of the components.

< laminate >

The laminate according to one embodiment of the present invention comprises, in order, a front panel, an adhesive layer, and a polarizing film, wherein the front panel comprises an ultra-thin glass and a hard coat layer, the adhesive layer has a storage modulus of 0.2MPa or less at a temperature of 25 ℃, and the polarizing film is a laminate comprising a cured liquid crystal layer comprising a cured product of a polymerizable liquid crystal compound.

Fig. 1 is a schematic cross-sectional view of a laminate according to an embodiment of the present invention. The laminate 100 shown in fig. 1 is formed by laminating a front panel 10, an adhesive layer 11, and a polarizing plate 12 in this order. The adhesive layer 11 may be disposed in contact with the front panel 10 and the polarizing plate 12. The front panel 10 includes ultra-thin glass 14 and a hard coat layer 13. The polarizing plate 12 is laminated with a base film 15, an alignment film 16, a polarizing film 17, and a protective layer 18 in this order from the viewing side (front panel 10 side). In addition to the above layers, the laminate 100 may further include other layers such as a retardation plate, a bonding layer, an organic EL panel, a touch sensor, and the like.

The front panel 10 side of the laminate 100 is bendable inward or outward with respect to a bending axis, and preferably the front panel 10 side is bendable inward with respect to the bending axis. The term "bendable" means bendable without generating cracks in the laminate. The bending includes a bending form in which a curved surface is formed in a bending portion. In the bent form, the bending radius of the bent inner surface is not particularly limited. The bend includes a bent shape in which the bend of the inner surface is larger than 0 ° and smaller than 180 °, and a folded shape in which the bend radius of the inner surface is approximately 0 or the bend angle of the inner surface is 0 °. The laminate of the present invention is flexible and suitable for flexible displays.

When the laminate 100 is repeatedly bent in the bending property evaluation described later, the bending radius at which cracking is less likely to occur may be, for example, 4mm or less, preferably 2mm or less, and more preferably 1.5mm or less. In the bending property evaluation described later, when the laminate 100 is repeatedly bent at a bending radius of 1.5mm, it is preferable that no crack is generated even if the number of times of bending is 20 ten thousand times, more preferably no crack is generated even if the laminate is bent 30 ten thousand times, and still more preferably no crack is generated even if the laminate is bent 40 ten thousand times. It is particularly preferable that no crack is generated even 50 ten thousand times.

The thickness of the laminate 100 may vary depending on the desired function of the laminate, the use of the laminate, and the like, and is not particularly limited, and is, for example, 30 μm to 4000 μm, preferably 2000 μm or less, and more preferably 1000 μm or less. In the present specification, the thickness of the laminate and each layer can be measured by the thickness measurement method described in examples described below.

The planar shape of the laminate 100 may be, for example, a square shape, preferably a square shape having long sides and short sides, and more preferably a rectangle. When the planar shape of the laminate 100 is rectangular, the length of the long side may be, for example, 10mm to 1400mm, and preferably 600mm or less. The length of the short side is, for example, 5mm to 800mm, preferably 500mm or less, and more preferably 300mm or less. The layers constituting the laminate may be formed by chamfering the corners, slitting the ends, or punching the holes.

(front panel)

The front panel 10 is an outermost surface layer constituting the visual recognition side of the image display device, and has a function of protecting the front surface (screen) of the image display device. The front panel 10 is a component that may be referred to as a window film. The front panel 10 includes ultra-thin glass 14 and a hard coat layer 13. The hard coat layer may be disposed on only one side of the ultra-thin glass, or may be disposed on both sides of the ultra-thin glass. In the present specification, a glass having a thickness of 50 μm or less is referred to as an ultra-thin glass.

The thickness of the front panel 10 may be, for example, 30 μm to 200 μm, preferably 100 μm or less, and more preferably 50 μm or less.

The thickness of the ultra-thin glass 14 may be 50 μm or less, for example. By using an ultra-thin glass having a thickness of 50 μm or less, the laminate tends to be thin and the flexibility and light transmittance of the laminate tend to be easily improved. The thickness of the ultra-thin glass 14 is preferably 45 μm or less, more preferably 40 μm or less, further preferably 35 μm or less, and particularly preferably 30 μm or less. The thickness of the ultra-thin glass 14 is generally 10 μm or more, and preferably 15 μm or more from the viewpoint of improving the impact resistance of the laminate.

The ultra-thin glass 14 is preferably chemically strengthened glass excellent in strength and light transmittance. By using chemically strengthened glass, the impact resistance of the laminate can be improved while maintaining the bendability (flexibility). Chemically strengthened glass can be obtained by chemical ion exchange treatment of glass. The sodium ions and lithium ions on the surface of the glass are partially replaced by potassium ions with larger ionic radius through chemical ion exchange treatment, so that the surface strength of the glass can be improved. Surface strength is improved by forming a thin compressive stress layer. Examples of the glass used for the chemically strengthened glass include aluminosilicate glass, soda lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

The chemical ion exchange treatment may be performed by immersing the glass in an ion exchange solution heated to a temperature higher than the melting point, or by directly coating a paste-like ion exchange solution on the glass. Examples of the ion exchange solution include potassium nitrate, potassium carbonate, potassium hydrogencarbonate, potassium phosphate, potassium sulfate, and potassium hydroxide-based solutions. Among them, potassium nitrate (330 ℃) has a melting point lower than that of glass (usually 500 to 600 ℃) and is preferable because of easy handling.

The etching treatment may be performed before the chemical ion exchange treatment, or the glass may be thinned. The etching treatment may be performed using hydrofluoric acid or a solution thereof mixed with an aqueous ammonium fluoride solution and an organic acid, such as formic acid, acetic acid, propionic acid, or the like, as a chemical treatment solution. Etching may be performed using such a method as spraying, dipping, or the like. Fluorine-containing inert gases, e.g. containing CF, may be used ₄ 、C ₃ F ₈ 、C ₂ F ₆ 、XeF ₂ Helium or argon of at least 1 of these gases is used as an etching gas to perform etching treatment. Specifically, inert gas containing fluorine diluted in helium or argon is plasmized at atmospheric pressure, and fluorine is ionized from fluorine carbide to etch.

The front panel 10 has a hard coat layer 13 on at least 1 side of the ultra-thin glass 14. By providing the hard coat layer 13, the laminate 100 tends to be easy to improve the handleability. In addition, by providing the hard coat layer 13, hardness and scratch resistance can be improved. In the case where the image display device provided with the front panel 10 is a touch panel type image display device, the front panel 10 preferably has the hard coat layer 13 because the surface of the front panel becomes a touch surface.

The hard coat layer 13 may be formed on one surface or both surfaces of the ultra-thin glass 14. When formed on both surfaces of the ultra-thin glass 14, the laminate 100 tends to be easy to improve the handleability. When the hard coat layer 13 is formed on one surface of the ultra-thin glass 14, it is preferably formed on a surface that becomes the viewing side when the laminate 100 is bonded to an image display device.

The hard coat layer 13 may be, for example, a cured layer of ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The hard coat layer 13 may also contain additives for improving hardness. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof.

The hard coat layer 13 may have a single-layer structure or a multilayer structure composed of 2 or more layers. In the case where the hard coat layer 13 has a multilayer structure, the laminate tends to be easy to improve the handleability. In the case where the hard coat layer 13 has a multilayer structure, the thickness of each layer and the material constituting each layer may be different from each other or may be the same. The multilayer structure may be a structure consisting of 2 or 3 layers, preferably 2 layers.

The thickness of the hard coat layer 13 may be, for example, 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and may be, for example, 50 μm or less or 40 μm or less or 30 μm or less.

When the hard coat layer 13 has a multilayer structure and is disposed on both sides of the ultra-thin glass, the total thickness of the hard coat layer may be, for example, 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and may be, for example, 50 μm or less, 40 μm or less, or 30 μm or less.

In order to improve the abrasion resistance and prevent contamination by sebum or the like, it is also preferable to form an abrasion-resistant layer on the visible side of the hard coat layer 13. The front panel 10 may have a wear-resistant layer, and the wear-resistant layer may be a layer constituting the viewing side surface of the front panel 10. The abrasion resistant layer may contain a structure derived from a fluorine compound. The fluorine compound is preferably a compound having a silicon atom and a hydrolyzable group such as an alkoxy group or halogen in the silicon atom. The hydrolyzable group can form a coating film by dehydration condensation reaction, and can improve adhesion of the abrasion-resistant layer by reaction with active hydrogen on the surface of the substrate. Furthermore, fluorine compounds having perfluoroalkyl groups or perfluoropolyether structures are preferable because they can impart water repellency. Particularly preferred are fluorine-containing polyorganosiloxane compounds having a perfluoropolyether structure and a long-chain alkyl group having 4 or more carbon atoms. As the fluorine compound, 2 or more kinds of compounds are also preferably used. The fluorine-containing organosiloxane compound preferably further contains a fluorine-containing compound containing an alkylene group having 2 or more carbon atoms and a perfluoroalkylene group.

The thickness of the abrasion-resistant layer may be, for example, 1nm to 20nm. The abrasion-resistant layer has hydrophobicity, and the water contact angle is, for example, about 110 to 125 °. The contact angle hysteresis and the slip angle measured by the slip method are about 3 to 20 degrees and about 2 to 55 degrees, respectively. The abrasion-resistant layer may contain various additives such as silanol condensation catalysts, antioxidants, rust inhibitors, ultraviolet absorbers, light stabilizers, mold inhibitors, antibacterial agents, antifouling agents, deodorants, pigments, flame retardants, antistatic agents, and the like, within a range that does not inhibit the effects of the present invention.

A primer layer may be disposed between the wear-resistant layer and the hard coat layer. Examples of the primer include ultraviolet-curable, thermosetting, moisture-curable, and two-component curable epoxy compounds. In addition, as the primer agent, polyamic acid can be used, and a silane coupling agent is also preferably used. The thickness of the primer layer is, for example, 0.001 to 2. Mu.m.

As a method for obtaining a front panel including an abrasion-resistant layer and a hard coat layer, a primer layer may be formed by applying a primer agent to the hard coat layer, if necessary, drying and curing the primer agent, and then a composition including a fluorine compound (composition for coating an abrasion-resistant layer) is applied and dried. Examples of the coating method include dip coating, roll coating, bar coating, spin coating, spray coating, die coating, and gravure coating. The coated surface is preferably subjected to hydrophilization treatment such as plasma treatment, corona treatment, or ultraviolet treatment before the primer or the composition for coating the abrasion-resistant layer is applied.

The front panel 10 may be provided with a resin film for improving impact resistance. The resin film is not limited as long as it is a resin film capable of transmitting light. Examples thereof include films made of polymers such as triacetylcellulose, acetylcellulose butyrate, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, levulinyl cellulose, polyester, polystyrene, polyamide, polyetherimide, poly (meth) acrylic acid, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polymethyl (meth) acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers may be used alone or in combination of 2 or more. When the laminate is used for a flexible display, a resin film formed of a polymer such as polyimide, polyamide, or polyamideimide, which can be configured to have excellent flexibility, high strength, and high transparency, is preferably used. In the present specification, "meth) acrylic acid" may refer to either acrylic acid or methacrylic acid. The "(meth)" in (meth) acrylate and the like is also intended to have the same meaning. The thickness of the resin film is, for example, 10 μm to 500. Mu.m, preferably 20 μm to 100. Mu.m.

(adhesive layer)

The adhesive layer 11 is sandwiched between the front plate 10 and the polarizing plate 12, and can bond them. The adhesive layer may be, for example, a layer made of an adhesive or a layer obtained by subjecting the layer to some kind of treatment. Adhesives are also known as pressure sensitive adhesives. In the present specification, "adhesive" means an adhesive other than an adhesive (pressure-sensitive adhesive), and is clearly distinguished from an adhesive. The pressure-sensitive adhesive layer may be 1 layer, or may be 2 or more layers, and is preferably 1 layer.

The storage modulus of the pressure-sensitive adhesive layer 11 at 25℃is 0.2MPa or less, preferably 0.1MPa or less, and more preferably 0.05MPa or less. The storage modulus of the adhesive layer 11 at 25℃was measured by the measurement method described in examples described below. By setting the storage modulus of the adhesive layer 11 at a temperature of 25 ℃ to 0.2MPa or less, the laminate 100 tends to easily improve the bendability.

The adhesive layer 11 is formed of an adhesive composition described later. The storage modulus of the pressure-sensitive adhesive layer 11 at a temperature of 25 ℃ can be adjusted by, for example, selecting the type of the monomer constituting the (meth) acrylic polymer contained in the pressure-sensitive adhesive composition, adjusting the molecular weight of the (meth) acrylic polymer, adjusting the crosslinking density according to the amount of the crosslinking agent added, adjusting the thickness of the pressure-sensitive adhesive layer, a method of combining them, and the like. The adhesive having the desired storage modulus may also be selected from commercially available adhesives.

The pressure-sensitive adhesive layer 11 may be composed of a pressure-sensitive adhesive composition containing a resin such as an acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin as a main component. Among them, an adhesive composition based on a (meth) acrylic resin excellent in transparency, durability, heat resistance and the like is preferable. The adhesive composition may be an active energy ray-curable type or a thermosetting type.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, a polymer or copolymer containing 1 or 2 or more kinds of (meth) acrylic acid esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate as monomers is preferably used. The base polymer preferably copolymerizes the polar monomers. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. Examples of the crosslinking agent include a metal ion having a valence of 2 or more and a metal salt of carboxylic acid formed between the metal ion and the carboxyl group; a substance which is a polyamine compound and forms an amide bond with a carboxyl group; a substance which is a polyepoxide, a polyhydric alcohol and forms an ester bond with a carboxyl group; a substance which is a polyisocyanate compound and forms an amide bond with a carboxyl group. Among them, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition which has a property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams, and has a property of having adhesiveness even before irradiation with active energy rays, being capable of being brought into close contact with an adherend such as a film, being cured by irradiation with active energy rays, and being capable of adjusting the adhesion force. The active energy ray-curable adhesive composition is preferably an ultraviolet ray-curable adhesive composition. The active energy ray-curable adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, a photopolymerization initiator, a photosensitizer, and the like may be contained as needed.

The adhesive composition may contain fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, an adhesion imparting agent, a filler (metal powder, other inorganic powder, etc.), an antioxidant, an ultraviolet absorber, a dye, a pigment, a colorant, a defoaming agent, an anticorrosive agent, an antistatic agent, a photopolymerization initiator, and other additives.

The adhesive layer 11 can be formed by applying an organic solvent dilution of the above adhesive composition to a substrate and drying. When the active energy ray-curable adhesive composition is used, a cured product having a desired degree of cure can be produced by irradiating the formed adhesive layer with active energy rays.

The thickness of the pressure-sensitive adhesive layer 11 is, for example, preferably 1 μm to 100 μm, more preferably 50 μm or less, still more preferably 30 μm or less, and may be 10 μm or more.

[ polarizing film ]

The polarizing film 17 is composed of a liquid crystal cured layer containing a cured product of a polymerizable liquid crystal compound. By forming the polarizing film 17 from a liquid crystal cured layer containing a cured product of a polymerizable liquid crystal compound, the laminate 100 tends to have improved flexibility. The liquid crystal cured layer containing the cured product of the polymerizable liquid crystal compound may be a polarizing layer composed of a layer obtained by curing a composition containing a polymerizable dichroic dye having liquid crystallinity or by applying a composition containing a polymerizable liquid crystal compound and a dichroic dye to a base film. As the dichroic dye, specifically, iodine or a dichroic organic dye can be used. Examples of the dichroic organic dye include azo dyes. The azo dye includes a dichroic direct dye composed of a disazo compound such as c.i. direct RED 39 and a dichroic direct dye composed of a compound such as trisazo or tetraazo.

An alignment film may be provided on one side of the base film. From the viewpoint of improving the bending property, the polarizing film 17 preferably includes a layer of a cured product of a composition containing a polymerizable liquid crystal compound and 1 or more azo-based pigments, and an alignment film. The thickness of the alignment film may be, for example, 5nm to 1. Mu.m.

If a liquid crystal cured layer containing a cured product of a polymerizable liquid crystal compound is embedded in the laminate, the polarizing film 17 may be embedded in the laminate together with the base film. The material and thickness of the base film may be the same as those of the thermoplastic resin film described later. A hard coat layer (HC layer) may be formed as a protective layer described later on at least one surface of the base film.

The thickness of the liquid crystal cured layer containing the cured product of the polymerizable liquid crystal compound is usually 10 μm or less, preferably 8 μm or less, and more preferably 5 μm or less.

Protective layer

The protective layer is disposed on one side or both sides of the polarizing film 17, and can protect the surface of the polarizing film 17. In this specification, a polarizing film having a protective layer laminated thereon is sometimes referred to as a polarizing plate.

The protective layer may be an organic layer or an inorganic layer. The organic layer or the inorganic layer may be a layer formed by coating. The organic layer may be a cured resin layer of a composition for forming a protective layer, for example, a (meth) acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like. The composition for forming a protective layer may be an active energy ray-curable composition or a thermosetting composition. The inorganic layer may be formed of, for example, silicon oxide or the like. When the protective layer is an organic layer, the protective layer may be referred to as a hard coat (HC layer), overcoat (OC) layer. The protective layer may be formed directly on the base film or may be formed directly on the polarizing film. The polarizing film may be formed after the protective layer is formed on the base film.

When the protective layer is an organic layer, for example, the active energy ray-curable composition for forming a protective layer can be applied to a base film and cured by irradiation with active energy to produce a protective layer. The substrate film is suitable for the description of the substrate film described above. The protective layer can be embedded in the laminate in a state where the base film is peeled off and removed. Examples of a method for applying the composition for forming a protective layer include spin coating. When the protective layer is an inorganic layer, the protective layer can be formed by, for example, sputtering, vapor deposition, or the like. When the protective layer is an organic layer or an inorganic layer, the thickness of the protective layer may be, for example, 0.1 μm to 10 μm, preferably 5 μm or less.

As the protective layer, for example, a thermoplastic resin film excellent in transparency, mechanical strength, thermal stability, moisture resistance, isotropy, stretchability, and the like can also be used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resin; polysulfone resin; a polycarbonate resin; polyamide resins such as nylon and aromatic polyamide; polyimide resin; polyolefin resins such as polyethylene, polypropylene, ethylene and propylene copolymers; a cyclic polyolefin resin (also referred to as norbornene-based resin) having a ring and a norbornene structure; (meth) acrylic resin; a polyarylate resin; a polystyrene resin; polyvinyl alcohol resins and mixtures thereof. When the protective layers are laminated on both sides of the polarizing film 17, the two protective layers may be the same or different. From the viewpoint of thickness reduction, 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 50 μm or less, still more preferably 30 μm or less, and further usually 1 μm or more, for example, 5 μm or more or 20 μm or more.

When the protective layer is a thermoplastic resin film, the thermoplastic resin film may be laminated on the polarizing film 17 via a later-described lamination layer, and the lamination layer for bonding the thermoplastic resin film to the polarizing film 17 is preferably an adhesive layer. Alternatively, a polarizing layer may be formed on the protective layer. The laminate 100 preferably includes a protective layer selected from at least one of a thermoplastic resin film and a cured resin layer on the side opposite to the adhesive layer 11 of the polarizing film 17.

[ other layers ]

(phase plate)

The laminate 100 may have a retardation plate on a lamination layer, which will be described later, on the side of the polarizing plate 12 opposite to the pressure-sensitive adhesive layer 11. The retardation plate may contain a cured layer of a polymerizable liquid crystal compound. The cured layer of the polymerizable liquid crystal compound can be formed by applying a composition for forming a retardation layer containing the polymerizable liquid crystal compound onto a base film and curing the composition. Examples of the coating method include a coating method and a printing method. Examples of the coating method include bar coating, doctor blade coating, flat plate coating, die coating, direct gravure coating, reverse gravure coating, roll coating, CAP coating, spin coating, spray coating, screen coating, slit coating, and dip coating. Examples of the printing method include offset printing, gravure printing, screen printing, and inkjet printing.

The cured layer of the polymerizable liquid crystal compound may be a retardation layer. The retardation layer may be composed of 1 layer or 2 layers or more. The retardation layer may be a positive a plate, a positive C plate, etc. of a lambda/4 plate, a lambda/2 plate, etc. When the retardation plate contains only 1 cured layer of the polymerizable liquid crystal compound, the retardation layer is preferably a lambda/4 plate. When the retardation plate contains 2 cured layers of a polymerizable liquid crystal compound, the retardation layer may be a retardation layer laminate composed of a 1 st liquid crystal cured retardation layer and a 2 nd liquid crystal cured retardation layer. The 1 st liquid crystal cured retardation layer and the 2 nd liquid crystal cured retardation layer may be laminated with an adhesive layer interposed therebetween, and are preferably laminated with an adhesive layer interposed therebetween. As the combination of the 1 st liquid crystal cured retardation layer and the 2 nd liquid crystal cured retardation layer, a combination of the 1 st liquid crystal cured retardation layer being a λ/4 plate and the 2 nd liquid crystal cured retardation layer being a λ/2 plate, and a combination of the 1 st liquid crystal cured retardation layer being a λ/4 plate and the 2 nd liquid crystal cured retardation layer being a positive C plate are preferable. In this specification, a polarizing plate having a retardation layer laminated thereon is sometimes referred to as a circular polarizing plate.

The thickness of the cured layer of the polymerizable liquid crystal compound is, for example, 0.1 μm to 10. Mu.m, preferably 8 μm or less, and more preferably 6 μm or less.

An alignment layer may be formed between the base film and the cured layer of the polymerizable liquid crystal compound. The material and thickness of the base film may be the same as those of the thermoplastic resin film described above. The retardation layer obtained by curing the polymerizable liquid crystal compound may be embedded in the laminate 100 together with either one or both of the alignment layer and the base film. The thickness of the alignment layer may be, for example, 5nm to 1. Mu.m.

(bonding layer)

The bonding layer is a layer made of an adhesive or an adhesive. The lamination layer may be, for example, a layer in which a polarizing film is laminated to a retardation plate, a layer in which a laminate is laminated to an organic EL panel, a touch sensor panel, a layer in which a polarizing film is bonded to a protective layer, a layer in which a 1 st liquid crystal cured retardation layer is bonded to a 2 nd liquid crystal cured retardation layer, or the like. The adhesive constituting the adhesive layer may be the same agent as exemplified for the adhesive composition constituting the adhesive layer, or may be other adhesives such as (meth) acrylic adhesives, styrene adhesives, silicone adhesives, rubber adhesives, urethane adhesives, polyester adhesives, epoxy copolymer adhesives, and the like. The laminate 100 may have 1 bonding layer or 2 or more bonding layers. When the laminate 100 includes a plurality of bonding layers, the plurality of bonding layers may be the same as or different from each other.

The adhesive constituting the adhesive layer may be formed by combining 1 or 2 or more kinds of aqueous adhesives, active-energy-ray-curable adhesives, and the like, for example. Examples of the aqueous adhesive include an aqueous polyvinyl alcohol resin solution and an aqueous two-part urethane emulsion adhesive. The active energy ray-curable adhesive is an adhesive cured by irradiation with active energy rays such as ultraviolet rays, and examples thereof include adhesives containing a polymerizable compound and a photopolymerization initiator, adhesives containing a photoreactive resin, adhesives containing an adhesive resin and a photoreactive crosslinking agent, and the like. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers, and photocurable urethane monomers, and oligomers derived from these monomers. The photopolymerization initiator may be a compound containing an active species such as a neutral radical, an anionic radical, or a cationic radical generated by irradiation with an active energy ray such as ultraviolet rays.

When the pressure-sensitive adhesive layer is used as the bonding layer, it is preferably 1 μm or more, but may be 5 μm or more, and is usually 200 μm or less, and may be 150 μm or less, or 100 μm or less, for example. When the adhesive layer is used as the bonding layer, the thickness of the bonding layer is preferably 0.1 μm or more, but may be 0.5 μm or more, preferably 10 μm or less, and may be 5 μm or less.

(organic EL panel)

The organic EL panel may be any known organic EL panel. The laminate 100 may include an organic EL panel on the side of the polarizing plate 12 opposite to the adhesive layer 11. When the laminate 100 has a retardation plate on the opposite side of the adhesive layer 11 from the polarizing plate 12, the organic EL panel may be disposed on the opposite side of the retardation plate from the polarizing plate 12.

(touch sensor Panel)

The touch sensor panel is not limited as long as it is a sensor capable of detecting a touched position, and examples thereof include a resistive film type, a capacitance type, an optical sensor type, an ultrasonic type, an electromagnetic induction coupling type, and a surface acoustic wave type. Among them, a capacitive touch sensor panel is preferably used in terms of low cost, high reaction speed, and thin film. 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 substrate film supporting the same. The adhesive layer may be an adhesive layer or an adhesive layer. Examples of the base film for supporting the transparent conductive layer include a base film formed by vapor deposition on one surface, a base film in which the transparent conductive layer is transferred via an adhesive layer, and the like.

An example of the capacitive touch sensor panel is composed of a base film, a transparent conductive layer for detecting a position provided on the surface of the base film, and a touch position detecting circuit. In an image display device provided with a laminate of touch sensor panels having a capacitance system, if the surface of a front panel is touched, a transparent conductive layer is grounded via the capacitance of a human body at the point where the touch is made. The touch position detection circuit detects the grounding of the transparent conductive layer and detects the touched position. By spacing the plurality of transparent conductive layers from each other, more detailed detection of the position can be performed.

The transparent conductive layer may be a transparent conductive layer made of a metal oxide such as ITO, or a metal layer made of a metal such as aluminum, copper, silver, gold, or an alloy thereof. The transparent conductive layer is formed by a coating method such as a sputtering deposition method, a printing method, or an evaporation method. A photoresist is formed on the transparent conductive layer, and then an electrode pattern layer is formed by photolithography. The photoresist uses a negative photoresist or a positive photoresist, and the photoresist may remain or be removed after patterning. In the case of producing a film by sputtering deposition, the electrode pattern layer may be formed by disposing a mask having an electrode pattern shape and performing sputtering deposition.

The separation layer may be a layer formed over a substrate such as glass, and the transparent conductive layer formed over the separation layer is separated from the substrate together with the separation layer. The separation layer is preferably an inorganic layer or an organic layer. As a material for forming the inorganic layer, for example, silicon oxide is given. As a material for forming the organic layer, for example, a (meth) acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like can be used. The separation layer may be formed by coating by a known coating method, and curing by heat curing or UV curing or a combination thereof.

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

The insulating layer may be formed of, for example, an inorganic insulating material such as silicon oxide or a transparent organic material such as an acrylic resin. The insulating layer is formed by heat curing, UV curing, heat drying, vacuum drying, or the like after being coated by a known coating method.

Examples of the substrate film of the touch sensor panel include resin films of triacetylcellulose, polyethylene terephthalate, cycloolefin polymer, polyethylene naphthalate, polyolefin, polycycloolefin, polycarbonate, polyethersulfone, polyarylate, polyimide, polyamide, polystyrene, polynorbornene, and the like. Polyethylene terephthalate is preferably used from the viewpoint of easy formation of a base film having desired toughness.

The thickness of the base film of the touch sensor panel is preferably 50 μm or less, more preferably 30 μm or less, from the viewpoint of easy formation of a laminate having excellent bending resistance. The thickness of the base film of the touch sensor panel may be, for example, 5 μm or more.

The touch sensor panel can be manufactured, for example, as follows. In method 1, first, a base film is laminated on a substrate via an adhesive layer. A transparent conductive layer patterned by photolithography is formed on the base film. The substrate and the base film are separated by heating, and a touch sensor panel composed of the transparent conductive layer and the base film is obtained. The substrate is not particularly limited as long as it maintains flatness and has heat resistance, and is preferably a glass substrate.

In method 2, first, a material for forming a separation layer is applied to a substrate to form a separation layer. The protective layer is formed by coating on the separation layer as needed. The protective layer may also be formed so that the protective layer is not formed on the portion where the pattern layer is formed. On the separation layer (or the protective layer), a transparent conductive layer is formed by patterning by photolithography. An insulating layer is formed on the transparent conductive layer to bury the electrode pattern layer. The protective film is laminated on the insulating layer with a releasable adhesive, and then transferred from the insulating layer to the separation layer, thereby separating the substrate. By peeling the peelable protective film, a touch sensor panel having an insulating layer/transparent conductive layer/(protective layer)/separation layer in this order is obtained.

When the base film is contained, the thickness of the touch sensor panel may be, for example, 5 μm to 2000 μm or 5 μm to 100 μm.

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

When the laminate 100 includes a touch sensor panel, the touch sensor panel may be disposed between, for example, the phase difference plate and the organic EL panel, or between the front panel 10 and the polarizing plate 12.

[ layer Structure of laminate ]

The laminate 200 shown in fig. 2 is formed by laminating a front panel 21, an adhesive layer 22, a polarizing plate 23, a bonding layer 24, and a retardation plate 25 in this order from the viewing side. The front panel 21 is formed by laminating a 1 st hard coat layer 26, a 2 nd hard coat layer 27, and an ultra-thin glass 28 in this order from the viewing side. The polarizing plate 23 is formed by laminating a base film 29, an orientation film 30, a polarizing film 31, and a protective layer 32 in this order from the viewing side. The retardation plate 25 is formed by laminating a 1 st liquid crystal cured retardation layer 33 and a 2 nd liquid crystal cured retardation layer 34 in this order from the viewing side.

Fig. 3 shows a layer structure of a laminate 300. The descriptions of the layers in fig. 3 are applied to the descriptions of the layers denoted by the same reference numerals in fig. 2. The laminate 300 has the same layer structure as the laminate 200 described above, except that the 1 st hard coat layer 26, the ultra-thin glass 28, and the 2 nd hard coat layer 27 are laminated in this order.

[ use of laminate ]

The laminate 100 can be used for an image display device or the like, for example. The image display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, and an electroluminescent display device. The image display device may have a touch panel function. The image display device may preferably be a flexible display. The laminate 100 may be arranged on the image display device such that the front panel 10 side is a visible side with respect to the adhesive layer 11, and the front panel 10 is preferably arranged so as to constitute the outermost surface of the image display device.

[ method for producing laminate ]

The laminate can be produced by a method including a step of bonding an adhesive layer or an interlayer of the laminate via an adhesive layer. When bonding between layers via an adhesive layer or an adhesive layer, a surface-active treatment such as corona treatment is preferably performed on one or both of the bonding surfaces in order to improve adhesion.

The liquid crystal cured layer containing the cured product of the polymerizable liquid crystal compound constituting the polarizing film may be formed on the substrate via an alignment film. The liquid crystal cured layer containing the cured product of the polymerizable liquid crystal compound can be formed by coating and curing a dichroic dye and a composition for forming a liquid crystal cured layer containing the polymerizable liquid crystal compound. The composition for forming a cured liquid crystal layer preferably further contains a polymerization initiator, a leveling agent, a solvent, a photosensitizer, a polymerization inhibitor, a leveling agent, and the like, in addition to the dichroic dye and the polymerizable liquid crystal compound.

The retardation layer included in the retardation plate can be produced by applying a composition for forming a retardation layer containing a polymerizable liquid crystal compound to a substrate and an alignment film present, and polymerizing the polymerizable liquid crystal compound. The composition for forming a retardation layer may further contain a solvent and a polymerization initiator, and may further contain a photosensitizer, a polymerization inhibitor, a leveling agent, and the like. The base material and the alignment film may be embedded in the retardation plate, or may be peeled off from the retardation plate without being a laminate component.

The coating, drying and polymerization of the composition for forming a liquid crystal cured layer and the composition for forming a retardation layer may be carried out according to conventionally known coating methods, drying methods and polymerization methods.

For example, as a coating method of the composition for forming a liquid crystal cured layer and the composition for forming a retardation layer, a bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, and the like can be used.

The polymerization method of the polymerizable liquid crystal compound may be selected according to the kind of the polymerizable group of the polymerizable liquid crystal compound. If the polymerizable group is a photopolymerizable group, polymerization can be performed by photopolymerization. If the polymeric group is a thermally polymerizable group, the polymerization may be carried out by a thermal polymerization method. In the production method of the present embodiment, photopolymerization is preferable. Since the photopolymerization method does not necessarily heat the transparent substrate to a high temperature, a transparent substrate having low heat resistance can be used. The photopolymerization method is performed by irradiating a film made of a composition for forming a liquid crystal cured layer or a composition for forming a retardation layer containing a polymerizable liquid crystal compound with visible light or ultraviolet light. From the viewpoint of easy handling, ultraviolet light is preferable.

An adhesive layer may be prepared as the adhesive sheet. The pressure-sensitive adhesive sheet can be produced, for example, by dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive liquid, forming a layer composed of a pressure-sensitive adhesive into a sheet-like shape on the release film subjected to the release treatment, and further bonding another release film to the pressure-sensitive adhesive layer. The layers may be bonded by bonding the adhesive sheet from which the release film on one side is peeled to the layer on one side, then peeling the release film on the other side, and then bonding the other layers.

As a method of applying the adhesive liquid to the release film, a general application technique such as a die coater, comma knife coater, reverse roll coater, gravure coater, bar coater, knife coater, air knife coater, or the like may be used.

The release film is preferably composed of a plastic film and a release layer. Examples of the plastic film include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film and polyethylene naphthalate film, and polyolefin films such as polypropylene film. The release layer may be formed of, for example, a composition for forming a release layer. The main component (resin) constituting the composition for forming a release layer is not particularly limited, and examples thereof include silicone resins, alkyd resins, acrylic resins, long-chain alkyl resins, and the like.

The thickness of the adhesive layer may be adjusted according to the application conditions of the respective adhesive solutions. It is effective to reduce the coating thickness in order to reduce the thickness of the adhesive layer.

< image display device >)

An image display device according to another aspect of the present invention includes the above-described laminate. The display device is not particularly limited, and examples thereof include image display devices such as organic EL display devices, inorganic EL display devices, liquid crystal display devices, and electroluminescent display devices. The image display device may have a touch panel function. The laminate is suitable for flexible displays having bendability, such as being bendable or bendable.

In the image display device, the laminate is arranged with the front panel facing outward (on the opposite side to the display element side, i.e., the viewing side) on the viewing side of the display element provided in the image display device.

The image display device can be used as mobile equipment such as smart phones, tablet computers and the like, televisions, digital photo frames, electronic billboards, measuring instruments, meters, office equipment, medical equipment, computer equipment and the like. The image display device has excellent picture visibility since distortion of a reflected image reflected on the front panel surface is suppressed.

Examples

The present invention is described in further detail below with reference to examples. In the examples, "%" and "parts" are mass% and parts unless otherwise specified.

[ measurement of thickness ]

The thickness of the ultra-thin glass, the adhesive layer and the resin film was measured using a contact film thickness measuring apparatus (MS-5C, nikon Co., ltd.). The polarizing layer and the alignment film were measured using a laser microscope (OLS 4100, olympus corporation).

[ measurement of storage modulus at 25 ]

The storage modulus of the adhesive layer at 25℃was measured using a viscoelasticity measuring device (trade name "MCR-301" manufactured by Anton Paar Co.). The adhesive layer was cut to 20mm wide by 20mm long, a plurality of adhesive layers were laminated so as to have a thickness of 150 μm, and the laminated adhesive layer was bonded to a glass plate. The adhesive layer is adhered to the measuring chip, and the storage modulus value at 25 ℃ is measured under the conditions of frequency 1.0Hz, deformation 1% and heating speed 5 ℃/min in the temperature range of-20 ℃ to 100 ℃.

[ evaluation of operability ]

The release film is peeled from the laminate with the pressure-sensitive adhesive layer to expose the pressure-sensitive adhesive layer, and then the laminate is bonded to the polarizing film via the pressure-sensitive adhesive layer exposed on the base (PAI film) to the retardation plate side. Then, the laminate was visually observed to confirm the occurrence of cracks. 10 samples of each of the examples and comparative examples were evaluated. The criterion is as follows.

And (3) the following materials: cracks occurred in 0 to 2 samples.

O: cracks occurred in 3 to 4 samples.

X: cracks occurred in 5 to 10 samples.

[ evaluation of bendability ]

The release film is peeled from the laminate with the adhesive layer to expose the adhesive layer. Next, the laminate with the adhesive layer and the polarizing plate opposite side of the retardation plate are bonded to a substrate (PAI film) via the adhesive layer. A bending evaluation apparatus (manufactured by Yuasa System, planar unloaded U-shaped extension test: DLDMLH-FS) was used. FIG. 4 is a schematic diagram showing the evaluation test method. As shown in fig. 4, two independently movable tables 401 and 402 are arranged so that the gap C is 3.0mm (bending radius 1.5 mm), and a laminate 400 is fixedly arranged at the center of the gap C so as to be positioned at the center in the width direction (fig. 4 a). At this time, the front panel is disposed above the laminate 400. Then, the two tables 401 and 402 are rotated upward by 90 degrees about the positions P1 and P2 as rotation axes, and bending force is applied to the region of the laminate 400 corresponding to the table gap C (fig. 4 b). After that, the two tables 401 and 402 are returned to the initial positions (fig. 4 (a)). After the above series of operations were completed, the number of times of applying the bending force was 1. After repeating this operation at room temperature, the occurrence of cracks was confirmed in the region corresponding to the gap C between the stages 401 and 402 corresponding to the laminate 400. The movement speed of the tables 401 and 402 and the bending force application rhythm were the same in all the laminate evaluation tests. The number of times of bending each laminate after bending was counted, and the criterion was as follows.

O: the number of bending times was 20 ten thousand times without generating cracks.

X: crack is generated when the bending back number is less than 20 ten thousand times.

(preparation of composition 1 for Forming hard coating)

2.0 parts by mass of a dendrimer acrylate having 18 acrylic functional groups (manufactured by Miramer SP1106, miwon Speciality Chemical), 10.0 parts by mass of a urethane acrylate having 6 acrylic functional groups (manufactured by Miramer PU-620D,Miwon Speciality Chemical Co., ltd.), 8 parts by mass of three acrylic functional groups of an acrylate monomer (manufactured by M340, miwon Speciality Chemical), 2 parts by mass of a photopolymerization initiator (manufactured by Irgacure (registered trademark) 184, manufactured by BASF), and 0.1 parts by mass of a leveling agent (manufactured by BYK-UV3530, manufactured by BYK. JAPAN Co., ltd.) were dissolved in 70 parts by mass of Methyl Ethyl Ketone (MEK) and mixed with stirring to obtain a composition 1 for forming a hard coating layer.

(preparation of composition 2 for Forming hard coating)

30 parts by mass of a multifunctional acrylate (manufactured by Miramer M340, miwon Specialty Chemical), 50 parts by mass of a nano silica sol propylene glycol monomethyl ether dispersion (12 nm, solid content: 40%), 17 parts by mass of ethyl acetate, 2.7 parts by mass of a photopolymerization initiator (manufactured by Irgacure-184,Ciba Corporation), and 0.3 parts by mass of a fluorine-based additive (KY 1203, manufactured by Xinyue chemical Co., ltd.) were mixed with stirring to obtain a composition 2 for forming a hard coat layer.

(production of front Panel A)

The composition 2 for forming a hard coat layer was applied to one surface of ultra-thin glass 1 (thickness: 50 μm) (UTG 1), and the obtained coating film was dried at a temperature of 80℃for 5 minutes, and was irradiated with UV light (SPOTCURE SP-7, manufactured by Ushio electric Co., ltd.) at 500mJ/cm ² An exposure amount of (365 nm standard) was irradiated with UV light to form a hard coat layer 2 (HC layer 2). The coating was performed so that the thickness after curing was 10. Mu.m. A front panel a having a layer structure of HC layer 2 (thickness 10 μm)/UTG 1 (thickness 50 μm) was obtained.

(production of front Panel B)

In the production of the front panel a, a front panel B having a layer structure of HC layer 2 (thickness 10 μm)/UTG 2 (thickness 30 μm) was obtained in the same manner as in the production of the front panel a except that UTG1 was changed to ultra-thin glass 2 (thickness 30 μm) (UTG 2).

(production of front Panel C)

The composition 1 for forming a hard coat layer was applied to one surface of UTG1, and the obtained coating film was dried at a temperature of 80℃for 5 minutes, and was irradiated with UV light (SPOTCURE SP-7, manufactured by Ushio electric Co., ltd.) at 500mJ/cm ² An exposure amount of (365 nm standard) was irradiated with UV light to form a hard coat layer 1 (HC layer 1). The coating was performed so that the thickness after curing was 10. Mu.m. Next, similarly, the HC layer 2 was formed on the HC layer 1 using the composition 2 for forming a hard coat layer, and the thickness after curing was set to 10 μm. As described above, the front panel C having a layer structure of HC layer 2 (thickness 10 μm)/HC layer 1 (thickness 10 μm)/UTG 1 (thickness 50 μm) was obtained.

(production of front Panel D)

A front panel D having a layer structure of HC layer 2 (thickness 10 μm)/HC layer 1 (thickness 10 μm)/UTG 2 (thickness 30 μm) was obtained in the same manner as in the production of the front panel a except that UTG1 was changed to UTG2 in the production of the front panel C.

(production of front Panel E)

The hard coat layer-forming composition 1 was applied to one surface of UTG, and the resulting coating film was dried at a temperature of 80℃for 5 minutes, and was irradiated with UV light (SPOTCURE SP-7, manufactured by Ushio electric Co., ltd.) at 500mJ/cm ² An exposure amount of (365 nm standard) was irradiated with UV light to form the HC layer 1. Coating to make the cured thicknessThe degree was 10. Mu.m. Next, similarly, the HC layer 2 was formed on the other surface of UTG using the hard coat layer-forming composition 2, and the thickness after curing was set to 10 μm. As described above, the front panel E having a layer structure of HC layer 2 (thickness 10 μm)/UTG 2 (thickness 30 μm)/HC layer 1 (thickness 10 μm) was obtained.

(production of adhesive sheet)

Adhesive compositions A, B, C for forming the adhesive layers A, B, C were prepared in accordance with the proportions of the respective components described in table 1 below. These adhesive compositions A, B, C were applied to release treated surfaces of release films (polyethylene terephthalate films, thickness 38 μm) after release treatment, respectively, using a coater, so that the thickness after drying was 25 μm. The coating layer was dried at 100 ℃ for 1 minute to give a film with an adhesive layer A, B, C. Then, another release film (polyethylene terephthalate film, thickness 38 μm) after the release treatment was attached to the adhesive layer A, B, C. Then, the resultant was cured at a temperature of 23℃and a relative humidity of 50% RH for 7 days to obtain an adhesive sheet A, B, C. Further, an adhesive sheet D having an adhesive layer D with a thickness of 5 μm was produced by using the adhesive composition C in the same procedure.

TABLE 1

The symbols in the columns of the monomers in Table 1 indicate the following meanings.

BA: butyl acrylate.

MMA: methyl acrylate.

EHA: acrylic acid 2-hexyl ethyl ester

AA: acrylic acid

The following reagents were used as the crosslinking agent and the silane coupling agent in Table 1.

Crosslinking agent: coronate L (Tosoh Co., ltd.)

Silane coupling agent: KBM-403 (Xinyue chemical industry Co., ltd.)

[ production of polarizing plate A ]

(substrate film)

A triacetyl cellulose (TAC) film (manufactured by Konica Minolta Co., ltd., thickness: 25 μm) was prepared as a base film.

(composition for Forming an alignment film)

The polymer 1 is a polymer having a photoreactive group constituted of the following structural units.

[ Structure 1 ]

The number average molecular weight of the obtained polymer 1 was 28200, mw/Mn was 1.82 and the monomer content was 0.5% as determined by GPC.

A solution in which polymer 1 was dissolved in cyclopentanone at a concentration of 5 mass% was used as the composition for forming an alignment film.

(polymerizable liquid Crystal Compound)

The polymerizable liquid crystal compound represented by the formula (1-6) [ hereinafter, also referred to as the compound (1-6) ] and the polymerizable liquid crystal compound represented by the formula (1-7) [ hereinafter, also referred to as the compound (1-7) ].

[ Structure 2 ]

[ Structure 3 ]

Compounds (1-6) and (1-7) were synthesized by the methods described in Lub et al, recl. Trav. Chim. Pays-Bas,115, 321-328 (1996).

(dichromatic pigment)

As the dichroic dye, an azo dye described in examples of Japanese patent application laid-open No. 2013-101328 represented by the following formulas (2-1 a), (2-1 b) and (2-3 a) is used.

[ Structure 4 ]

[ Structure 5 ]

[ Structure 6 ]

(composition for Forming liquid Crystal cured layer)

The composition for forming a cured liquid crystal layer was prepared by mixing 75 parts by mass of compound (1-6), 25 parts by mass of compound (1-7), 2.5 parts by mass of each of the azo pigments represented by the above-mentioned formulas (2-1 a), (2-1 b) and (2-3 a) as a dichroic pigment, 6 parts by mass of 2-dimethylamino-1- (4-morpholinophenyl) butan-1-one (Irgacure 369, manufactured by BASF JAPAN) as a polymerization initiator, and 1.2 parts by mass of a polyacrylate compound (BYK-361 n, manufactured by BYK-Chemie) as a leveling agent in 400 parts by mass of a toluene solvent, and stirring the resultant mixture at 80 ℃ for 1 hour.

(composition for protective layer (OC layer))

The composition for protective layer was prepared by mixing 3 parts by mass of polyvinyl alcohol resin powder (Kuraray, average polymerization degree 18000, trade name: KL-318) with 1.5 parts by mass of polyamide epoxy resin (crosslinking agent, trade name: SR650 (30), manufactured by Chemtex Co., ltd.) with respect to 100 parts by mass of water.

(production of polarizing film)

Corona treatment is applied to the substrate film. The corona treatment condition was 0.3kW output, and the treatment speed was 3 m/min. Thereafter, the composition for forming an alignment film was applied to the base film by a bar coating method, and heated and dried in a drying oven at 80 ℃ for 1 minute. The obtained dry film was compactedShi Pianguang UV irradiation treatment to form an alignment film. The polarized UV treatment was carried out by passing light irradiated from a UV irradiation device (SPOTCURESP-7; manufactured by Ushio Motor Co., ltd.) through a wire grid (UIS-27132 #, manufactured by Ushio Motor Co., ltd.) to measure the cumulative light quantity at a wavelength of 365nm at 100mJ/cm ² Is carried out under the condition of (2). The thickness of the alignment film was 100nm.

The composition for forming a cured liquid crystal layer was applied to the formed alignment film by a bar coating method, and the film was dried by heating in a drying oven at 120℃for 1 minute and then cooled to room temperature. By using the UV irradiation apparatus described above, the cumulative light amount was irradiated to the dry film at 1200mJ/cm ² Ultraviolet rays (365 nm standard) form a liquid crystal cured layer (polarizing film). The thickness of the resulting cured liquid crystal layer was 1.8 μm as measured by a laser microscope (OLS 3000, olympus Co.). In this way, a laminated film a having a layer structure of a base film/an alignment film/a liquid crystal cured layer was obtained.

The composition for the protective layer (OC layer) was coated on the formed liquid crystal cured layer by a bar coating method so that the thickness after drying was 1.0 μm, and dried at 80 ℃ for 3 minutes. In this way, a polarizing plate a composed of a base film/an alignment film/a liquid crystal cured layer/a protective layer (OC layer) was obtained.

[ production of polarizing plate B ]

(protective layer)

Cycloolefin polymer (COP) film (ZF-14, manufactured by Japanese ZEON Co., ltd., thickness: 23 μm) was prepared as a protective film.

(polarizing film)

A long polyvinyl alcohol (PVA) film (trade name "Kuraray Poval film VF-PE#3000 by Kuraray Co., ltd.," average polymerization degree 2400, saponification degree 99.9 mol% or more) having a thickness of 30 μm was continuously transported while being wound out of the roll, and immersed in a swelling bath composed of pure water at 20℃for a residence time of 31 seconds (swelling step). Thereafter, the film extracted from the swelling bath was immersed in a dyeing bath containing iodine at 30℃with a potassium iodide/water ratio of 2/100 (weight ratio) and a residence time of 122 seconds (dyeing step). Next, the film extracted from the dyeing bath was immersed in a crosslinking bath at 56 ℃ with a residence time of 70 seconds, and then immersed in a crosslinking bath at 40 ℃ with a residence time of 9/2.9/100 (weight ratio) with a residence time of 13 seconds (crosslinking step). In the dyeing step and the crosslinking step, stretching in the machine direction-machine direction is performed by stretching between rolls in a bath. The total draw ratio based on the original film was 5.4 times. Then, the film extracted from the crosslinking bath was immersed in a cleaning bath composed of pure water at 5℃for 3 seconds (cleaning step), and then introduced into a 1 st heating furnace capable of adjusting humidity, and subjected to high-temperature and high-humidity treatment (high-temperature and high-humidity treatment step) for 190 seconds to obtain a polarizing film (PVA) having a thickness of 12.1. Mu.m.

(adhesive composition)

Water is mixed with: 100 parts by weight of a polyvinyl alcohol resin powder (manufactured by Kuraray, average polymerization degree 18000, trade name: KL-318): 3 parts by weight of a polyamide epoxy resin (crosslinking agent, trade name: SR650 (30)) made by Chemtex Co., ltd.): 1.5 parts by weight of a resin was mixed to obtain an adhesive composition.

Corona treatment is performed on the polarizing film and the protective layer. The corona treatment condition was 0.3kW output, and the treatment speed was 3 m/min. Then, these were bonded via an adhesive composition, and dried at 60 ℃ for 2 minutes to obtain a polarizing plate B composed of a protective layer/polarizing layer.

[ production of phase-difference plate ]

(1 st liquid Crystal cured retarder)

A layer of lambda/4 retardation composed of a nematic liquid crystal compound cured layer, an alignment layer and a transparent substrate was prepared as a 1 st liquid crystal cured retardation layer. The total thickness of the layer cured with the nematic liquid crystal compound and the alignment layer was 2. Mu.m. The layer cured by the nematic liquid crystal compound is formed by applying a composition for forming a retardation layer containing the nematic liquid crystal compound onto an alignment layer formed on a substrate film (transparent substrate) and curing the composition.

(2. Liquid Crystal cured phase-difference layer)

A polyethylene terephthalate substrate having a thickness of 38 μm was used as a substrate film (transparent substrate) and one side thereof was coated with a homeotropic alignmentComposition for layer, having a film thickness of 3 μm, was irradiated with 20mJ/cm ² To produce an alignment layer. Acrylic acid esters of 2-phenoxyethyl ester, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate and bis (2-ethyleneoxyethyl) ether were used in the amounts of 1:1:4:5, and a LUCIRIN (registered trademark) TPO as a polymerization initiator is added in a proportion of 4%, and the mixture is used as a composition for a homeotropic alignment layer.

Next, a composition for forming a retardation layer containing a photopolymerizable nematic liquid crystal (RMM 28B, manufactured by Merck corporation) was applied to the formed alignment layer by a die coating method. Here, as the solvent in the liquid crystal composition, methyl Ethyl Ketone (MEK), methyl isobutyl ketone (MIBK), and Cyclohexanone (CHN) having a boiling point of 155 ℃ were used in a mass ratio (MEK: MIBK: CHN) of 35:30:35, and a mixed solvent mixed in a ratio of 35. Then, the composition for forming a retardation layer prepared so that the solid content is 1 to 1.5g is applied to the alignment layer so that the applied amount is 4 to 5g (wet weight).

After the composition for forming a retardation layer was applied to the alignment layer, a drying treatment was performed at a drying temperature of 75℃for a drying time of 120 seconds. Then, the liquid crystal compound was polymerized by Ultraviolet (UV) irradiation to obtain a layer cured with a photopolymerizable nematic liquid crystal compound, an alignment layer, and a positive C layer composed of a transparent substrate. The total thickness of the layer cured with the photopolymerizable nematic liquid crystal compound and the alignment layer was 4. Mu.m.

(production of phase-difference plate)

The 1 st liquid crystal cured retardation layer and the 2 nd liquid crystal cured retardation layer were bonded with an ultraviolet curable adhesive, and each liquid crystal cured retardation layer (the surface opposite to the transparent substrate) was made to be a bonding surface. Then, the ultraviolet-curable adhesive is cured by irradiation with ultraviolet rays. The thickness of the ultraviolet-curable adhesive after curing was 2. Mu.m. In this manner, a retardation plate having a layer structure of a base film/alignment layer/1 st liquid crystal cured retardation layer (2 μm)/adhesive layer (thickness 2 μm)/2 nd liquid crystal cured retardation layer (thickness 4 μm)/alignment layer/base film was produced.

Example 1 >

The release film was peeled off from one side of the adhesive sheet D, and the exposed adhesive layer D was bonded to the protective layer side of the polarizing plate a, to obtain a laminate A1. Double-sided corona treatment (output 0.3kW, speed 3 m/min) was performed on the bonding surface in advance.

The base film on the 1 st liquid crystal cured retardation layer side of the retardation plate was peeled off, and the other peeled film was peeled off from the laminate A1 to expose the adhesive layer D. Further, the adhesive layer D of the laminate A1 was bonded to the 1 st liquid crystal cured retardation layer of the retardation plate, to obtain a laminate A2. Double-sided corona treatment (output 0.3kW, speed 3 m/min) was performed on the bonding surface in advance.

The release film was peeled off from one side of the adhesive sheet a to expose the adhesive layer a. Next, the exposed adhesive layer a was bonded to the surface of the laminate A2 from which the base film for forming the 2 nd liquid crystal cured retardation layer was peeled, to obtain a laminate A3. Double-sided corona treatment (output 0.3kW, speed 3 m/min) was performed on the bonding surface in advance.

The release film on one side is peeled from the other adhesive sheet a (referred to as adhesive sheet a ') and the adhesive layer a (referred to as adhesive layer a') is exposed. Next, the exposed adhesive layer a' was bonded to the UTG side of the front panel, to obtain a laminate A4. Double-sided corona treatment (output 0.3kW, speed 3 m/min) was performed on the bonding surface in advance.

The other release film was peeled from the laminate A4 to expose the adhesive layer a'. Next, the adhesive layer a' of the laminate A4 was bonded to the substrate film side of the polarizing plate a of the laminate A3, to obtain a laminate with an adhesive layer. Double-sided corona treatment (output 0.3kW, speed 3 m/min) was performed on the bonding surface in advance. The results are shown in Table 2.

Examples 2 to 6 and comparative examples 1 to 4 >, respectively

A laminate with an adhesive layer was obtained in the same manner as in example 1, except that the front panel, the polarizing film, and the adhesive layer of the type shown in table 1 were used as the front panel, the polarizing film, and the adhesive layer joining the front panel and the polarizing film. In example 5, the adhesive layer a was bonded to the HC layer 1 side of the front panel. In comparative examples 1 and 2, UTG and UTG2, each of which had no hard coat layer formed thereon, were used as front panels. Further, in comparative example 5, the adhesive layer was directly bonded to the polarizing film B. The results are shown in Table 2.

TABLE 2

Symbol description

100. 200, 300, 400 of the laminate,

10. a front panel of the type 21,

11. 22 a layer of adhesive,

12. a 23-polarization plate, which is used for polarizing the light,

13 a hard-coat layer of a coating,

14. 28 ultra-thin type glass is manufactured,

24 the layer of the adhesive is applied,

a 25-phase difference plate,

26 the 1 st hard coat layer of the coating,

a 27 nd hard coat layer of the composition,

15. a 29-substrate film comprising a substrate,

16. 30 an orientation film of the glass,

17. 31 polarizing film (liquid crystal cured layer),

18. a 32-protective layer is provided,

33 the 1 st liquid crystal cured retardation layer,

34 the 2 nd liquid crystal cured retardation layer,

401. 402 mounting table.

Claims

1. A laminate comprising a front panel, an adhesive layer and a polarizing film in this order,

the front panel comprises ultra-thin glass and a hard coat layer,

2. The laminate according to claim 1, wherein the ultra-thin glass has a thickness of 50 μm or less.

3. The laminate according to claim 1, wherein the hard coat layer has a thickness of 10 μm or more.

4. The laminate according to claim 2, wherein the hard coat layer has a thickness of 10 μm or more.

5. The laminate according to any one of claims 1 to 4, wherein the adhesive layer has a storage modulus of 0.01MPa or more at a temperature of 25 ℃.

6. The laminate according to any one of claims 1 to 4, wherein the adhesive layer has a thickness of 30 μm or less.

7. The laminate according to claim 5, wherein the adhesive layer has a thickness of 30 μm or less.

8. An image display device comprising the laminate according to any one of claims 1 to 4.

9. An image display device comprising the laminate of claim 5.

10. An image display device comprising the laminate of claim 6.

11. An image display device comprising the laminate of claim 7.