JP7205202B2 - LAMINATED BODY AND IMAGE DISPLAY DEVICE USING THE SAME - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminate and an image display device using the same.

2. Description of the Related Art In recent years, mobile phones, tablet terminals, and the like have become popular, and liquid crystal display devices and organic EL display devices (OLED) have come to be widely used as image display devices. In addition, along with the thinning of the display device, thinning of each member such as a polarizing plate to be used is required. For example, in an organic EL display device, a circularly polarizing plate is usually arranged on the viewing side surface of the organic EL panel in order to suppress external light from being reflected by a metal electrode (cathode) and viewed like a mirror surface. be.

As the circularly polarizing plate, a laminate of a polarizing plate and a λ/4 plate is generally used. For example, a polarizer and a single retardation layer having specific refractive index characteristics are laminated. is also known (see, for example, Patent Document 1).

Patent No. 3325560 JP 2014-123134 A

However, the λ / 4 plate using a stretched film has a limit to thinning, and a λ / 4 plate using a layer in which a liquid crystal compound is cured has been proposed for further thinning (for example, Patent Document 2 reference). Although such a layer obtained by curing a liquid crystal compound is advantageous for thinning, it has a weak mechanical strength and cracks may occur when an impact is applied from the outside.

The present invention has been made to solve the above problems, and the main object thereof is to provide a laminate comprising a very thin layer in which a liquid crystal compound having excellent impact resistance is cured, and an image comprising the laminate. An object of the present invention is to provide a display device and a method for manufacturing the laminate.

That is, the present invention provides the following laminate, image display device, and method for producing the laminate.
[1] A laminate comprising a polymerizable liquid crystal film and a support formed on at least one surface of the polymerizable liquid crystal film, the support having a pattern structure.
[2] The laminate according to [1], wherein the support has at least one structure selected from the group consisting of a honeycomb structure, a truss structure, a rigid frame structure, a stripe structure, and a circular structure.
[3] The laminate according to [1] or [2], wherein the support has a thickness of 1 μm to 15 μm.
[4] The laminate according to any one of [1] to [3], wherein the support has a width of 500 μm to 3000 μm in plan view.
[5] The laminate according to any one of [1] to [4], wherein the support is optically isotropic.
[6] The laminate according to any one of [1] to [5], comprising an embedding resin layer that embeds the support on the one surface of the polymerizable liquid crystal film.
[7] The laminate according to any one of [1] to [6], wherein the compression modulus of the support at 23°C is 0.01 GPa to 8.0 GPa.
[8] A laminate comprising the laminate according to any one of [1] to [7] and a polarizer.
[9] A laminate comprising the laminate according to any one of [1] to [7] and a retardation film.
[10] A laminate comprising the laminate according to any one of [1] to [7] and a touch sensor.
[11] A laminate comprising the laminate according to any one of [1] to [7] and a window film.
[12] An image display device comprising the laminate according to any one of [1] to [11].
[13] A method for producing a laminate, comprising the steps of: forming a pattern of a resin material on at least one surface of a polymerizable liquid crystal film; and curing the resin material to form a support having a pattern structure.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to obtain a laminate including a very thin layer in which a liquid crystal compound having excellent impact resistance is cured, an image display device provided with the laminate, and a method for producing the laminate. .

It is a top view of the layered product concerning one embodiment of the present invention. 1 is a cross-sectional view of a laminate according to one embodiment of the invention; FIG. FIG. 4 is a plan view of a laminate according to another embodiment of the invention; FIG. 5 is a plan view of a laminate according to still another embodiment of the present invention; FIG. 5 is a plan view of a laminate according to still another embodiment of the present invention; FIG. 5 is a plan view of a laminate according to still another embodiment of the present invention; FIG. 4 is a cross-sectional view of a laminate according to still another embodiment of the present invention; FIG. 4 is a cross-sectional view of a laminate according to still another embodiment of the present invention;

Preferred embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows.
(1) refractive index (nx, ny, nz)
“nx” is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), “ny” is the in-plane direction orthogonal to the slow axis, and “nz” is the thickness direction. is the refractive index.
(2) In-plane Retardation Value The in-plane retardation value (Re(λ)) refers to the in-plane retardation value of the film at 23° C. and wavelength λ (nm). Re(λ) is determined by Re(λ)=(nx−ny)×d, where d (nm) is the thickness of the film.
(3) Retardation value in thickness direction The in-plane retardation value (Rth(λ)) is the retardation value in the thickness direction of the film at 23°C and wavelength λ (nm). Rth(λ) is determined by Rth(λ)=((nx+ny)/2−nz)×d, where d (nm) is the thickness of the film.

(Overall structure of laminate)
FIG. 1 is a plan view of a laminate according to one embodiment of the invention. FIG. 2 is a cross-sectional view of a laminate according to one embodiment of the invention. As shown in FIG. 2, the laminate 10 has a layer 1 having a cured liquid crystal compound and a support 2 formed on one surface of the layer 1 having a cured liquid crystal compound. The laminate 10 may be in the shape of a sheet or in the shape of a long sheet. The thickness of the layer in which the liquid crystal compound is cured is typically 15 μm or less. The thickness of the support 2 is typically 1 μm to 15 μm, and the width of the support 2 in plan view is typically 500 μm to 3000 μm. The support 2 is preferably transparent, more preferably transparent and substantially optically isotropic. The support 2 has a pattern structure, typically a honeycomb structure as shown in FIG.

3-6 are plan views of laminates according to other embodiments of the present invention. The support may have a rigid-frame structure as shown in FIG. 3, a truss structure as shown in FIG. 4, or a circular structure as shown in FIG. arranged structure), or may have a stripe structure as shown in FIG. Thus, in the case of forming the patterned support 2 on the surface of the layer 1 in which the liquid crystal compound is cured, the material constituting the support is more difficult than in the case of forming the support on the entire surface of the cured layer 1. can reduce the amount used.

FIG. 7 is a cross-sectional view of a laminate according to yet another embodiment of the invention. As shown in FIG. 7, the laminate 11 has a support 2 (hereinafter sometimes referred to as a first support 2) on one side of a layer 1 in which a liquid crystal compound is cured. A support 3 (hereinafter sometimes referred to as a second support 3 ) is provided on the other surface of the layer 1 . The second support 3 has a pattern structure. The pattern structure of the second support 3 may be the same as or different from the pattern structure of the first support 2 . When the pattern structure of the first support 2 and the pattern structure of the second support 3 are the same, preferably the first support 2 and the second support 3 are separated as shown in FIG. and are arranged so that the areas of the portions that overlap with each other are small in plan view.

FIG. 8 is a cross-sectional view of a laminate according to yet another embodiment of the invention. As shown in FIG. 8, the laminate 12 includes an embedding resin layer 4 for embedding the support 2 on one surface of the layer 1 in which the liquid crystal compound is cured. Thereby, the step formed by the support 2 can be smoothed. Furthermore, by covering the exposed portion of the layer 1 with the cured liquid crystal compound with the embedding resin layer 4, the surface of the layer 1 with the cured liquid crystal compound can be protected. Note that two or more of the above embodiments may be combined.

The laminate of the present invention may have a function as a polarizer, or may have a function as a retardation film. In the former case, the layer with the cured liquid crystal compound may be a polarizer, and in the latter case, the layer with the cured liquid crystal compound may be a retardation film.

(Layer with cured liquid crystal compound)
A layer obtained by curing a liquid crystal compound used in the present invention can function as a retardation film such as a so-called λ/4 plate, λ/2 plate, and positive C plate. Moreover, the laminate of the present invention can comprise any two or more layers selected from these retardation films. A retardation film including a layer in which a liquid crystal compound is cured can be produced by coating a composition containing a liquid crystal compound on an alignment film and curing the composition.

The layer in which the liquid crystal compound is cured can be formed from a liquid crystal material. By using a liquid crystal material, the retardation film formed of a liquid crystal material can significantly increase the difference between nx and ny of the obtained retardation layer as compared with a non-liquid crystal material. As a result, the thickness of the retardation layer for obtaining a desired in-plane retardation value can be significantly reduced. For example, it can contribute to thinning of the resulting circularly polarizing plate and image display device. In addition, roll-to-roll is possible in manufacturing the circularly polarizing plate, and the manufacturing process can be significantly shortened.

The liquid crystal material preferably has a nematic liquid crystal phase (nematic liquid crystal). The liquid crystallinity manifestation mechanism of the liquid crystal material may be lyotropic or thermotropic. The alignment state of the liquid crystal material is preferably homogeneous alignment or homeotropic alignment. As the liquid crystal material, for example, a liquid crystal compound such as a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal polymer and liquid crystal monomer may be used alone or in combination.

The retardation film can be a cured layer of a liquid crystal material. Specifically, when the liquid crystal material is a liquid crystalline monomer, it is preferably a polymerizable monomer and/or a crosslinkable monomer. This is because the alignment state of the liquid crystalline monomer can be fixed by polymerizing or cross-linking the liquid crystalline monomer. After aligning the liquid crystalline monomers, for example, the alignment state can be fixed by polymerizing or cross-linking the liquid crystalline monomers. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by cross-linking, but these are non-liquid crystalline. Therefore, the formed retardation layer does not undergo a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a change in temperature, which is peculiar to liquid crystalline compounds. As a result, the retardation film can be a highly stable layer that is not affected by temperature changes.

In order for the layer formed by polymerizing the polymerizable liquid crystal to exhibit an in-plane retardation, the polymerizable liquid crystal may be oriented in a suitable direction. When the polymerizable liquid crystal is rod-shaped, an in-plane retardation is expressed by aligning the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, the optical axis direction and the slow axis direction are match. When the polymerizable liquid crystal is disk-shaped, an in-plane retardation occurs by aligning the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, the optical axis and the slow axis are perpendicular to each other. do. The alignment state of the polymerizable liquid crystal can be adjusted by a combination of the alignment film and the polymerizable liquid crystal.

<Polymerizable liquid crystal>
A polymerizable liquid crystal is a compound having a polymerizable group and liquid crystallinity. A polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical or acid generated from a photopolymerization initiator, which will be described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group and oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal may be either thermotropic liquid crystal or lyotropic liquid crystal, and thermotropic liquid crystal may be classified into nematic liquid crystal or smectic liquid crystal according to the degree of order.

The thickness of the layer in which the liquid crystal compound is cured can be set so as to function most appropriately as the designed retardation value. In other words, the thickness can be set to obtain desired optical properties. The thickness of the retardation layer is preferably 1.5 to 10 μm, more preferably 1.5 to 8 μm, particularly preferably 1.5 to 5 μm.

The layer obtained by curing the liquid crystal compound used in the present invention may include an alignment film for aligning the liquid crystal.

Another preferred form of the layer in which the liquid crystal compound used in the present invention is cured is one that can function as a liquid crystal coated polarizer containing a dichroic dye.

As the liquid crystal compound, it is sufficient if it has a property of exhibiting a liquid crystal state, and in particular, it is preferable to have a high-order alignment state such as a smectic phase because high polarizing performance can be exhibited. Further, the liquid crystal compound preferably has a polymerizable group, and can be the polymerizable liquid crystal described above. A dichroic dye is a dye that exhibits dichroism by aligning with a liquid crystal compound, and the dichroic dye itself may have liquid crystallinity or may have a polymerizable group. . Any compound in the composition containing the liquid crystal compound has a polymerizable group. The composition containing the liquid crystal compound may further contain initiators, solvents, dispersants, leveling agents, stabilizers, surfactants, cross-linking agents, silane coupling agents and the like. A liquid crystal-coated polarizer can be produced by applying a composition containing a liquid crystal compound onto an alignment film and curing the composition. A liquid crystal-coated polarizer can be formed thinner than a film-type polarizer. In this case, the thickness of the layer obtained by curing the liquid crystal compound may be 0.5 to 5 μm, preferably 1 to 4 μm.

(support)
The laminate of the present invention has a support on at least one surface of the layer in which the liquid crystal compound is cured. The support has a pattern structure as described above. The support preferably has at least one structure selected from the group consisting of a honeycomb structure, a truss structure, a rigid frame structure, a striped structure and a circular structure. The support more preferably has a honeycomb structure, a truss structure, or a circular structure, and particularly preferably has a honeycomb structure or a circular structure. When the support has a honeycomb structure, a truss structure, or a circular structure, when a layer of a cured liquid crystal compound receives stress in one direction, the stress can be dispersed in directions different from the direction, resulting in This is because the layer in which the liquid crystal compound is cured can absorb external impact and suppress cracking.

The support is preferably transparent and substantially optically isotropic. In the present specification, the term "substantially optically isotropic" means that, for example, the in-plane retardation Re (550) and the thickness direction retardation Rth (550) of the support are each preferably 20 nm or less. and more preferably 10 nm or less.

When the pattern structure of the first support formed on one side of the layer in which the liquid crystal compound is cured and the pattern structure of the second support formed on the other side are the same, the second support The support is preferably arranged so that the area of the portion overlapping the first support is small in plan view.

As described above, the thickness of the support is preferably 1 μm to 15 μm, more preferably 3 μm to 8 μm. The ratio (t2/t1) of the thickness (t2) of the support to the thickness (t1) of the layer obtained by curing the liquid crystal compound is preferably 0.13 to 5.00, more preferably 0.38 to 4.0. 00, more preferably 0.63 to 3.33.

The compression elastic modulus of the support at 23° C. is preferably 0.01 GPa to 8.0 GPa, more preferably 0.02 GPa to 6.0 GPa. This makes it possible to improve the workability and flexibility of the cured liquid crystal compound layer while suppressing the cracking of the cured liquid crystal compound layer due to an external impact. The compression modulus can be measured by a nanoindentation method.

The support can be formed of any appropriate material and method as long as it satisfies the above constitution and has sufficient adhesion to the layer in which the liquid crystal compound is cured. Adhesion of the support to the layer in which the liquid crystal compound is cured can be evaluated according to the cross-cut peeling test of JIS K5400. The adhesion of the support to the layer in which the liquid crystal compound is cured is preferably such that the number of peels is 0 in the cross-cut peel test (number of substrates: 100).

In one embodiment, the support having a pattern structure forms a pattern of a resin material or a coating liquid containing a resin material on the surface of a layer in which a liquid crystal compound is cured, and cures (or solidifies) the resin material. can be formed by In another embodiment, the support can be formed by vapor-depositing an inorganic oxide such as SiO ₂ on the surface of the layer in which the liquid crystal compound is cured.

Any appropriate material can be used as the resin material as long as the effects of the present invention can be obtained. Examples of the resin material include polyester-based resins, polyether-based resins, polycarbonate-based resins, polyurethane-based resins, silicone-based resins, polyamide-based resins, polyimide-based resins, PVA-based resins, acrylic-based resins, epoxy-based resins, fluorine system resins. These may be used alone or in combination (eg, blended, copolymerized).

A method for forming a pattern of the resin material or the coating liquid on the surface of the layer in which the liquid crystal compound is cured is not particularly limited. Examples of such methods include printing, photolithography, inkjet, nozzle, die coating, and the like. The pattern of the resin material or the coating liquid is preferably formed by printing. Methods for printing the coating liquid in a pattern include letterpress printing, direct gravure printing, intaglio printing, lithographic printing, stencil printing, and the like. The coating liquid may contain any appropriate other component in addition to the above resin material within a range that does not impair the effects of the present invention. Such other components include, for example, resin components other than the resin material as the main component, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foil materials, softeners, anti-aging agents. , conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The conditions for curing (or solidifying) the resin material (coating liquid) can be appropriately set according to the type of the resin material, the composition of the composition, and the like. For example, the resin material can be cured (or solidified) by drying, active energy ray curing, heat curing, or the like.

(Embedded resin layer)
The embedding resin layer embeds the support formed on one surface of the layer in which the liquid crystal compound is cured, as described above. The thickness of the embedding resin layer is thicker than the thickness of the support, preferably 3 μm to 150 μm, more preferably 5 μm to 100 μm. The embedding resin layer may be any appropriate functional layer formed according to the properties required for the layer in which the liquid crystal compound is cured. Examples of the functional layer include a hard coat layer, an adhesive layer, a transparent optical adhesive layer, and the like. When the embedding resin layer is a hard coat layer, its thickness is, for example, 5 μm to 15 μm. When the embedding resin layer is an adhesive layer, its thickness is, for example, 5 μm to 30 μm. When it is an optical adhesive layer, its thickness is, for example, 25 μm to 125 μm. The embedding resin layer is preferably transparent and substantially optically isotropic.

The embedding resin layer can be formed by any appropriate material and method as long as the layer in which the liquid crystal compound is cured and sufficient adhesiveness to the support are obtained. In one embodiment, the embedding resin layer can be made of a different type of resin material than the support. The embedded resin layer can be formed by forming a resin layer on the surface of the layer in which the liquid crystal compound is cured so as to embed the support, and curing the resin layer.

The method of forming the resin layer on the surface of the layer in which the liquid crystal compound is cured is not particularly limited. In one embodiment, the resin layer can be formed by applying a coating liquid containing a resin material to the surface of the polarizer. Any appropriate coating method can be used as the coating method. Specific examples include the curtain coating method, dip coating method, spin coating method, print coating method, spray coating method, slot coating method, roll coating method, slide coating method, blade coating method, gravure coating method, and wire bar method. be done. Curing conditions can be appropriately set according to the type of resin material used, the composition of the composition, and the like. The coating liquid may contain any appropriate other component in addition to the above resin material within a range that does not impair the effects of the present invention. Such other components include, for example, resin components other than the resin material as the main component, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foil materials, softeners, anti-aging agents. , conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The laminate of the present invention preferably has a support on the side opposite to the side to which the impact is applied (for example, the viewing side) with respect to the layer in which the liquid crystal compound is cured. With such an arrangement, the impact applied to the layer in which the liquid crystal compound is cured can be efficiently relieved, and cracking of the layer in which the liquid crystal compound is cured can be significantly prevented. When the laminate comprises two or more layers of cured liquid crystal compounds, it is also preferable to dispose a support having a pattern structure between the layers of cured liquid crystal compounds.

The laminate of the present invention may have a form in which any other functional layer is laminated. For example, a polarizer is laminated on a retardation film containing a layer in which a liquid crystal compound is cured, or a circularly polarizing plate is formed by laminating a retardation film on a polarizer containing a layer in which a liquid crystal compound is cured, or a liquid crystal compound. A touch sensor or a window film can be laminated on the cured layer to further add functions. These layers can be laminated together via an adhesive or pressure-sensitive adhesive, which will be described later.

<Image display device>
An image display device of the present invention is characterized by having the laminate of the present invention. From the viewpoint of facilitating the prevention of cracks occurring in the layer in which the liquid crystal compound is cured, the image display device of the present invention preferably includes a layer in which the liquid crystal compound is cured, a support, and a display panel in this order from the viewing side.

Any known image display device can be used regardless of the type of image display device. For example, the laminate of the present invention can be suitably used for organic EL display devices. For example, it can be suitably used as an antireflection polarizing plate for a flexible organic EL display device.

<Flexible image display device>
The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel. there is The laminate for a flexible image display device may contain a window, a circularly polarizing plate, and a touch sensor, and the order of lamination thereof is arbitrary. It is preferable that the touch sensor and the circularly polarizing plate are laminated in this order. When the circularly polarizing plate is present on the viewing side of the touch sensor, the pattern of the touch sensor becomes less visible and the visibility of the displayed image is improved, which is preferable. Each member can be laminated using an adhesive, a pressure-sensitive adhesive, or the like. Also, a light shielding pattern may be formed on at least one surface of any one of the window, circularly polarizing plate, and touch sensor layers. The laminate of the present invention can be a retardation film or a polarizer that constitutes a circularly polarizing plate.

<Window>
The window is arranged on the viewing side of the flexible image display device, and plays a role in protecting other components from external shocks or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window in a flexible image display device is not rigid and hard like glass, but has flexible characteristics. The window is made of a flexible transparent substrate, and may include a hard coat layer on at least one surface.

The transparent substrate used for the window has a visible light transmittance of 70% or more, preferably 80% or more. Any transparent polymer film can be used as the transparent substrate. Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene, or cycloolefin derivatives having a monomer unit containing cycloolefin, (modified) cellulose such as diacetyl cellulose, triacetyl cellulose, and propionyl cellulose acrylics such as methyl methacrylate (co)polymers, polystyrenes such as styrene (co)polymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene copolymers, ethylene-vinyl acetate copolymers Polyvinyl chlorides, polyvinylidene chlorides, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyesters such as polycarbonate and polyarylate, polyamides such as nylon, polyimides, polyamideimides, polyetherimides, Films formed of polymers such as polyethersulfones, polysulfones, polyvinyl alcohols, polyvinyl acetals, polyurethanes, and epoxy resins may be used, and unstretched uniaxially or biaxially stretched films may be used. can be done. Each of these polymers can be used alone or in combination of two or more. Among the transparent substrates described above, preferred are polyamide films, polyamideimide films, polyimide films, polyester films, olefin films, acrylic films, and cellulose films, which are excellent in transparency and heat resistance. It is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles, etc. in the polymer film. In addition, colorants such as pigments and dyes, optical brighteners, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. may contain a compounding agent. The thickness of the transparent substrate is 5-200 μm, preferably 20-100 μm.

The window may be provided with a hard coat layer on at least one surface of the transparent substrate. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is less than 2 μm, it is difficult to ensure sufficient scratch resistance. .

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure upon irradiation with an active energy ray or thermal energy, but is preferably formed by active energy ray curing. An active energy ray is defined as an energy ray capable of decomposing a compound that generates active species to generate active species. Visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays and electron beams can be used as active energy rays. UV light is particularly preferred. The hard coat composition contains at least one polymer of a radically polymerizable compound and a cationic polymerizable compound.

The radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group possessed by the radically polymerizable compound may be any functional group capable of causing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specific examples include a vinyl group and a (meth)acryloyl group. When the radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different. The number of radically polymerizable groups in one molecule of the radically polymerizable compound is preferably two or more from the viewpoint of improving the hardness of the hard coat layer. The radically polymerizable compound is preferably a compound having a (meth)acryloyl group from the viewpoint of high reactivity, and a polyfunctional acrylate monomer having 2 to 6 (meth)acryloyl groups in one molecule. Compounds called epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate and oligomers having several (meth) acryloyl groups in the molecule and having a molecular weight of several hundred to several thousand are preferred. Available. It preferably contains one or more selected from epoxy (meth)acrylate, urethane (meth)acrylate and polyester (meth)acrylate.

The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, or a vinyl ether group. The number of cationically polymerizable groups in one molecule of the cationically polymerizable compound is preferably two or more, more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer. As the cationically polymerizable compound, among others, a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group is preferable. A cyclic ether group such as an epoxy group or an oxetanyl group is preferable from the viewpoint that shrinkage accompanying a polymerization reaction is small. In addition, among the cyclic ether groups, compounds having epoxy groups are readily available in various structures, do not adversely affect the durability of the resulting hard coat layer, and are easy to control compatibility with radically polymerizable compounds. There is an advantage. In addition, among the cyclic ether groups, the oxetanyl group tends to have a higher degree of polymerization than the epoxy group, is less toxic, accelerates the rate of network formation obtained from the cationically polymerizable compound in the resulting hard coat layer, and radicals It has the advantage of forming an independent network without leaving unreacted monomers in the film even in a region mixed with a polymerizable compound.

Examples of cationic polymerizable compounds having an epoxy group include polyglycidyl ethers of polyhydric alcohols having an alicyclic ring, or compounds containing cyclohexene rings or cyclopentene rings, which are treated with a suitable oxidizing agent such as hydrogen peroxide or peracid. Alicyclic epoxy resin obtained by epoxidation; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long-chain polybasic acid, homopolymer of glycidyl (meth)acrylate, Aliphatic epoxy resins such as copolymers; bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or derivatives such as alkylene oxide adducts and caprolactone adducts thereof, and glycidyl ethers produced by reaction with epichlorohydrin, and glycidyl ether type epoxy resins derived from bisphenols such as novolac epoxy resins.

The hard coat composition may further include a polymerization initiator. Examples of the polymerization initiator include radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc., and can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to promote radical polymerization and cationic polymerization.

Any radical polymerization initiator may be used as long as it can release a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. Examples of thermal radical polymerization initiators include organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutyronitrile.

As active energy ray radical polymerization initiators, Type 1 type radical polymerization initiators that generate radicals by decomposition of molecules and Type 2 type radical polymerization initiators that generate radicals by hydrogen abstraction reaction in coexistence with tertiary amines are used. Yes, they can be used alone or in combination.

The cationic polymerization initiator should be capable of releasing a substance that initiates cationic polymerization by at least one of active energy ray irradiation and heating. As cationic polymerization initiators, aromatic iodonium salts, aromatic sulfonium salts, cyclopentadienyl iron (II) complexes and the like can be used. These can initiate cationic polymerization by either or both of active energy ray irradiation and heating depending on the difference in structure. The polymerization initiator may be included in an amount of 0.1-10% by weight based on 100% by weight of the hard coat composition. If the content of the polymerization initiator is less than 0.1% by weight, curing may not proceed sufficiently, and it may be difficult to realize the mechanical properties and adhesion of the finally obtained coating film. If the content is more than % by weight, adhesion failure, cracking, and curling may occur due to cure shrinkage.

The hard coat composition may further include one or more selected from the group consisting of solvents and additives. The solvent is capable of dissolving or dispersing the polymerizable compound and the polymerization initiator, and any solvent known as a solvent for hard coat compositions in this technical field can be used without limitation. The additives may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

<Touch sensor>
A touch sensor is used as an input means. Various types of touch sensors have been proposed, such as a resistive film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitive type, and any type may be used. Among them, the capacitance method is preferable. A capacitive touch sensor is divided into an active area and a non-active area located outside the active area. The active area is an area corresponding to the area (display part) where the screen is displayed on the display panel, and is an area where a user's touch is sensed. display area). The touch sensor includes a flexible substrate; sensing patterns formed in an active area of the substrate; and formed in a non-active area of the substrate, and is connected to an external driving circuit through the sensing patterns and pads. can include each sensing line for As the flexible substrate, the same material as the transparent substrate of the window can be used. The substrate of the touch sensor preferably has a toughness of 2,000 MPa % or more from the viewpoint of suppressing cracks in the touch sensor. More preferably, the toughness may be 2,000 MPa% to 30,000 MPa%.

The sensing patterns may include first patterns formed in a first direction and second patterns formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed in the same layer, and each pattern should be electrically connected to sense a touched point. The first pattern has a form in which each unit pattern is connected to each other through a joint, but the second pattern has a structure in which each unit pattern is separated from each other in an island form. A separate bridge electrode is required for connection. A known transparent electrode material can be applied to the sensing pattern. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly(3,4- ethylenedioxythiophene), carbon nanotube (CNT), graphene, metal wire, etc., and these can be used alone or in combination of two or more. Preferably ITO can be used. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, terenium, and chromium. These can be used alone or in combination of two or more.

A bridge electrode may be formed on the insulating layer above the sensing pattern via an insulating layer, and the bridge electrode may be formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrodes may be made of the same material as the sensing pattern, such as metals such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or alloys of two or more thereof. You can also Since the first pattern and the second pattern should be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joints and the bridge electrodes of the first pattern, or it may be formed in a structure of layers covering the sensing pattern. In the latter case, the bridge electrode can connect the second pattern through a contact hole formed in the insulating layer. The touch sensor is characterized by the difference in transmittance between patterned areas and non-patterned areas, specifically the difference in optical transmission induced by the difference in refractive index in these areas. An optical adjustment layer may be further included between the substrate and the electrode as a means for appropriately compensating for the difference, and the optical adjustment layer may include an inorganic insulating material or an organic insulating material. The optical adjustment layer may be formed by coating a photocurable composition containing a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The inorganic particles may increase the refractive index of the optical adjustment layer.

The photocurable organic binder may include, for example, copolymers of monomers such as acrylate-based monomers, styrene-based monomers, and carboxylic acid-based monomers. The photocurable organic binder may be, for example, a copolymer containing different repeating units such as epoxy group-containing repeating units, acrylate repeating units, and carboxylic acid repeating units. The inorganic particles can include, for example, zirconia particles, titania particles, alumina particles, and the like. The photocurable composition may further include additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

Each layer (window, circularly polarizing plate, touch sensor) forming the laminate for a flexible image display device can be laminated with an adhesive. Adhesives include water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent volatile adhesives, moisture-curable adhesives, heat-curable adhesives, anaerobic-curable adhesives, and active energy ray-curable adhesives. General-purpose adhesives such as adhesives, curing agent-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives (adhesives), and remoistening adhesives can be used. Among them, water-based solvent volatilization type adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives are often used. The thickness of the adhesive layer can be appropriately adjusted according to the desired adhesive strength and the like, and is 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. Although it exists, each thickness type may be the same or may be different.

As the water-based solvent volatilization type adhesive, water-soluble polymers such as polyvinyl alcohol-based polymers, starch, ethylene-vinyl acetate-based emulsions, styrene-butadiene-based emulsions, and other polymers in a water-dispersed state can be used as main polymers. In addition to water and the main polymer, a cross-linking agent, a silane compound, an ionic compound, a cross-linking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, and the like may be blended. When bonding with the water-based solvent volatilization type adhesive, adhesion can be imparted by injecting the water-based solvent volatilization type adhesive between the layers to be adhered, laminating the layers to be adhered, and then drying. When the water-based solvent volatilization type adhesive is used, the thickness of the adhesive layer may be 0.01 to 10 μm, preferably 0.1 to 1 μm. When multiple layers of the water-based solvent volatile adhesive are used, the thickness of each layer may be the same or different.

The active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material that forms an adhesive layer upon irradiation with an active energy ray. The active energy ray-curable composition can contain at least one polymer of the same radically polymerizable compound and cationic polymerizable compound as in the hard coat composition. The radically polymerizable compound is the same as that of the hard coat composition, and the same types of compounds as those of the hard coat composition can be used. A compound having an acryloyl group is preferable as the radically polymerizable compound used in the adhesive layer. It is also preferable to contain a monofunctional compound in order to reduce the viscosity of the adhesive composition.

The cationically polymerizable compound is the same as that of the hard coat composition, and the same types of compounds as those of the hard coat composition can be used. Epoxy compounds are particularly preferred as the cationic polymerizable compound used in the active energy ray-curable composition. It is also preferred to contain a monofunctional compound as a reactive diluent in order to reduce the viscosity of the adhesive composition.

The active energy ray composition may further contain a polymerization initiator. Examples of the polymerization initiator include radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc., and can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to promote radical polymerization and cationic polymerization. In the description of the hard coat composition, an initiator capable of initiating at least one of radical polymerization and cationic polymerization upon exposure to active energy rays can be used.

The active energy ray-curable composition further includes an ion scavenger, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, an antifoaming agent solvent, an additive, and a solvent. can include When bonding with the active energy ray-curable adhesive, the active energy ray-curable composition is applied to either or both of the adherend layers and then laminated, and activated through either adherend layer or both adherend layers. It can be adhered by curing by irradiating energy rays. When the active energy ray-curable adhesive is used, the adhesive layer may have a thickness of 0.01 to 20 μm, preferably 0.1 to 10 μm. When using a plurality of layers of the active energy ray-curable adhesive, the thickness of each layer may be the same or different.

The adhesive is classified into an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, etc. according to the main polymer, and any of them can be used. In addition to the base polymer, the adhesive may contain a cross-linking agent, a silane compound, an ionic compound, a cross-linking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, an inorganic filler, and the like. An adhesive layer is formed by dissolving and dispersing each component constituting the adhesive in a solvent to obtain an adhesive composition, applying the adhesive composition on a substrate and then drying it. be. The adhesive layer may be formed directly, or may be transferred after being separately formed on the substrate. It is also preferable to use a release film to cover the adhesive surface before adhesion. When the active energy ray-curable adhesive is used, the thickness of the adhesive layer may be 0.1 to 500 μm, preferably 1 to 300 μm. When multiple layers of the pressure-sensitive adhesive are used, the thickness of each layer may be the same or may be different.

(Shading pattern)
The light shielding pattern can be applied as at least part of a bezel or housing of the flexible image display device. The visibility of the image is improved by hiding the wiring arranged at the peripheral portion of the flexible image display device by the light shielding pattern and making it difficult to see. The light shielding pattern may be in the form of a single layer or multiple layers. The color of the light-shielding pattern is not particularly limited, and includes various colors such as black, white, and metallic color. The light-shielding pattern may be formed of pigments for realizing colors and polymers such as acryl-based resin, ester-based resin, epoxy-based resin, polyurethane, and silicone. These may be used singly or as a mixture of two or more. The light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light shielding pattern may be 1 μm to 100 μm, preferably 2 μm to 50 μm. It is also preferable to impart a shape such as an inclination in the thickness direction of the light pattern.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to obtain a laminate including a very thin layer in which a liquid crystal compound having excellent impact resistance is cured, an image display device provided with the laminate, and a method for producing the laminate. It is useful because

1 layer in which liquid crystal compound is cured 2 support (first support)
3 support (second support)
4 embedded resin layer 10 laminate 11 laminate 12 laminate

Claims (12)

A laminate comprising a layer in which a liquid crystal compound is cured and a support formed on at least one surface of the layer in which the liquid crystal compound is cured, the support having a pattern structure ;
display panel and
An image display device comprising
An image display device comprising a layer obtained by curing the liquid crystal compound, the support, and the display panel in this order from the viewing side . 2. The image display device according to claim 1, wherein said support has at least one structure selected from the group consisting of a honeycomb structure, a truss structure, a rigid frame structure, a stripe structure, and a circular structure. 3. The image display device according to claim 1, wherein the support has a thickness of 1 μm to 15 μm. 4. The image display device according to claim 1, wherein the support has a width of 500 μm to 3000 μm in plan view. The image display device according to any one of claims 1 to 4, wherein the support has optical isotropy. 6. The image display device according to any one of claims 1 to 5, further comprising an embedding resin layer that embeds the support on the one surface of the layer in which the liquid crystal compound is cured. The image display device according to any one of claims 1 to 6, wherein the support has a compression modulus at 23°C of 0.01 GPa to 8.0 GPa. The image display device according to any one of claims 1 to 7, wherein the laminate according to any one of claims 1 to 7 further comprises a polarizer . The image display device according to any one of claims 1 to 7, wherein the laminate according to any one of claims 1 to 7 further comprises a retardation film . The image display device according to any one of claims 1 to 7, wherein the laminate according to any one of claims 1 to 7 is a laminate further having a touch sensor . The image display device according to any one of claims 1 to 7, wherein the laminate according to any one of claims 1 to 7 further comprises a window film . forming a pattern of a resin material on at least one surface of a layer in which the liquid crystal compound is cured;
curing the resin material to form a support having a pattern structure;
obtaining a laminate;
and laminating a viewing side of a display panel on the support side of the laminate.
A method for manufacturing an image display device .

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