Sealing sheet, sealing sheet for transparent device, and method for producing electrode laminate

Abstract

To provide a sealing sheet which can be used for sealing a component of a device requiring transparency, and can reduce dot-like defects which may occur on the surface of a sealing material.SOLUTION: A sealing sheet comprising: a release sheet having a thickness of 150 μm or more; and a first elastomer layer provided in contact with a first main surface of the release sheet, wherein a storage modulus of the first elastomer layer at 23 °C is 0. 1GPa or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an encapsulating sheet, an encapsulating sheet for a transparent device, and a method for producing an electrode laminate. [Background technology]

[0002] 2. Description of the Related Art In order to protect elements such as light emitting elements from water and oxygen in the environment, the elements are protected with a sealing material. For example, a film-like sealing material for sealing a light-emitting element is known. In order to suppress the generation of bubbles between the light-emitting element and the sealing material and local light-emitting defects of the light-emitting element that occur during sealing of the light-emitting element, it is known that the surface of the film-like sealing material is roughened to have a specific arithmetic mean roughness (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 153030 Summary of the Invention [Problem to be solved by the invention]

[0004] Electrodes used in transparent devices such as touch panels are usually provided in the path of light. For example, touch panels are usually provided in image display devices, and are input devices that allow a user to input information by touching a predetermined location while referring to an image displayed on the display surface of the image display device as needed. Therefore, touch panels are required to be transparent so as not to impair the clarity of the image displayed on the image display device.

[0005] Sealing materials are used to prevent defects such as electrode deterioration and destruction, but when sealing components of devices that require transparency with a sheet-like sealing material, defects in the form of point-like depressions may occur on the surface of the sealing material. Since point-like defects affect the transparency of the sealed device, it is preferable to reduce them.

[0006] Therefore, there is a need for an encapsulating sheet that can be used to encapsulate components of a device that require transparency and that can reduce point-like defects that occur on the surface of the encapsulant; an encapsulating sheet for a transparent device that includes the encapsulating sheet; and a method for producing an electrode laminate using the encapsulating sheet. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by an encapsulating sheet in which a release sheet and a thermoplastic elastomer layer having a specific storage modulus are combined as a sheet-like encapsulating material, and have thus completed the present invention. The present invention provides the following:

[0008] <1> a release sheet having a thickness of 150 μm or more, and a first thermoplastic elastomer layer provided in contact with a first main surface of the release sheet; The encapsulating sheet, wherein the storage modulus of the first thermoplastic elastomer layer at 23°C is 0.1 GPa or more. <2> The thickness of the release sheet is 300 μm or more. <1> The encapsulating sheet according to claim 1. <3> The first thermoplastic elastomer layer Aromatic vinyl compound-conjugated diene block copolymer, and Hydrogenated aromatic vinyl compound-conjugated diene block copolymer Contains one or more selected from the group consisting of <1> or <2> The encapsulating sheet according to claim 1. <4> The release sheet contains one or more resins selected from the group consisting of vinyl chloride resin, polyimide resin, and polycarbonate resin. <1> ~ <3> The encapsulating sheet according to any one of the preceding claims. <5> The film further includes a second thermoplastic elastomer layer, and includes the release sheet, the first thermoplastic elastomer layer, and the second thermoplastic elastomer layer in this order in the thickness direction. <1> ~ <4> The encapsulating sheet according to any one of the preceding claims. <6> The second thermoplastic elastomer layer Aromatic vinyl compound-conjugated diene block copolymers modified with silicon atom-containing polar groups, and Modified hydrogenated aromatic vinyl compound-conjugated diene block copolymers with silicon atom-containing polar groups Contains one or more selected from the group consisting of <5> The encapsulating sheet according to claim 1. <7> The release sheet includes a substrate layer and a release layer. <1> ~ <6> The encapsulating sheet according to any one of the preceding claims. <8> The arithmetic mean roughness Ra of the first main surface of the release sheet is 10 nm or less; <1> ~ <7> The encapsulating sheet according to any one of the preceding claims. <9> <1> ~ <8> An encapsulating sheet for a transparent device, comprising the encapsulating sheet according to any one of claims 1 to 4. <10> <1> ~ <8> a step (1) of overlaying the encapsulating sheet according to any one of the above items on an electrode layer to form an intermediate laminate including the release sheet, the first thermoplastic elastomer layer, and the electrode layer in this order; Step (2) of pressing the intermediate laminate; and a step (3) of peeling the release sheet from the pressed intermediate laminate to form an electrode laminate; A method for manufacturing an electrode stack, comprising: [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an encapsulating sheet that can be used to encapsulate components of a device that require transparency and that can reduce point-like defects that may occur on the surface of an encapsulant; an encapsulating sheet for a transparent device that includes the encapsulating sheet; and a method for producing an electrode laminate that uses the encapsulating sheet. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an encapsulating sheet according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an encapsulating sheet according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents. The components of the embodiments shown below can be combined as appropriate. For example, any numerical value selected from the group of numerical values ​​listed as the lower limit and any numerical value selected from the group of numerical values ​​listed as the upper limit can be combined as appropriate. In addition, in the drawings, the same components are denoted by the same reference numerals, and their description may be omitted.

[0012] In the following description, a "long" film refers to a film having a length that is 5 times or more its width, preferably 10 times or more its width, and specifically refers to a film having a length that can be wound into a roll for storage or transportation. There is no particular upper limit to the length of the film, and it can be, for example, 100,000 times or less its width.

[0013] In the following description, the term "(meth)acrylic acid" includes "acrylic acid", "methacrylic acid", and combinations thereof. The term "(meth)acrylic acid ester" includes "acrylic acid ester", "methacrylic acid ester", and combinations thereof. The term "(meth)acrylamide" includes "acrylamide", "methacrylamide", and combinations thereof. The term "(meth)acrylonitrile" includes "acrylonitrile", "methacrylonitrile", and combinations thereof.

[0014] A structural unit having a structure formed by polymerizing a certain monomer is called a "monomer unit" by adding "unit" after the name of the monomer. For example, a structural unit having a structure formed by polymerizing an aromatic vinyl compound is called an "aromatic vinyl compound unit," and a structural unit having a structure formed by polymerizing a linear conjugated diene compound is called a "linear conjugated diene compound unit." However, the "monomer unit" is not limited by the method of formation. Generally, the monomer unit is a repeating unit.

[0015] In the following description, unless otherwise specified, the term "adhesive" refers not only to adhesives in the narrow sense (adhesives having a shear storage modulus of 1 MPa to 500 MPa at 23°C after irradiation with energy rays or after heat treatment), but also to pressure-sensitive adhesives having a shear storage modulus of less than 1 MPa at 23°C. Therefore, the term "adhesive layer" encompasses not only a layer of an adhesive in the narrow sense, but also a layer of a pressure-sensitive adhesive.

[0016] Thermoplastic elastomers are materials that exhibit rubber properties at room temperature but become plasticized at elevated temperatures, allowing them to be molded. These thermoplastic elastomers are characterized by their tendency to elongate easily under small loads while resisting breakage. Specifically, at 23°C, thermoplastic elastomers exhibit a storage modulus of 0.001 to 2 GPa and a tensile elongation (elongation at break) of 100 to 1000%. Furthermore, at high temperatures ranging from 40°C to 200°C, thermoplastic elastomers exhibit a sharp decrease in storage modulus, with the loss tangent tanδ (loss modulus / storage modulus) either peaking or exceeding 1, indicating softening. Tensile elongation can be measured according to JIS K7113. The storage modulus and loss tangent tanδ can be measured using a commercially available dynamic viscoelasticity measuring device.

[0017] <1. Encapsulating sheet> <1.1. Overview of encapsulating sheets> The encapsulating sheet according to one embodiment of the present invention comprises: a release sheet having a thickness of 150 μm or more, and a first thermoplastic elastomer layer provided in contact with a first main surface of the release sheet; The first thermoplastic elastomer layer has a storage modulus at 23° C. of 0.1 GPa or more. The encapsulating sheet of the present embodiment includes a combination of a thick release sheet and a thermoplastic elastomer layer having a high storage modulus at 23°C, and therefore, when the encapsulating sheet is overlaid on an object to be encapsulated and an intermediate laminate obtained is pressed to encapsulate the object, point-like defects are unlikely to occur in the first thermoplastic elastomer layer. Therefore, the influence of the first thermoplastic elastomer layer on the optical properties of the encapsulated product can be reduced. It is believed that point-like defects that can occur in the first thermoplastic elastomer layer are caused by foreign matter adhering to the surface of the encapsulating sheet, specifically the surface of the release sheet, being pressed against the surface of the release sheet by pressure. According to the encapsulating sheet of this embodiment, even if foreign matter is pressed against the surface of the release sheet, the release sheet has a large thickness and the storage modulus of the first thermoplastic elastomer layer, which is the layer below the release sheet, is equal to or greater than a predetermined value. As a result, local deformation of the release sheet due to foreign matter is reduced and the first thermoplastic elastomer layer is less likely to deform, making it less likely that point-like defects will occur in the first thermoplastic elastomer layer. Hereinafter, point-like defects that occur in the first thermoplastic elastomer layer by pressure will also be referred to as dents.

[0018] <1.2. First Thermoplastic Elastomer Layer> The first thermoplastic elastomer layer typically has a storage modulus of 0.1 GPa or more at 23° C. Here, the storage modulus of a certain layer at 23° C. refers to the storage modulus at 23° C. measured by preparing a film-like sample 10 mm wide and 40 mm long from the material constituting the layer using a dynamic viscoelasticity measuring device at a frequency of 1 Hz and a heating rate of 4° C. / min.

[0019] The storage modulus of the first thermoplastic elastomer layer at 23°C is usually 0.1 GPa or more, preferably more than 0.1 GPa, and more preferably 0.2 GPa or more, and from the viewpoint of allowing the first thermoplastic elastomer layer to deform well in response to deformation such as bending of the object to be sealed, it is preferably 2.0 GPa or less, more preferably 1.0 GPa or less, even more preferably 0.8 GPa or less, and even more preferably 0.5 GPa or less.

[0020] The storage modulus at 23°C of the first thermoplastic elastomer layer can be adjusted, for example, by adjusting the weight average molecular weight of the polymer that can be contained in the thermoplastic elastomer that forms the first thermoplastic elastomer layer, or by adjusting the proportion of structural units that constitute the copolymer that can be contained in the thermoplastic elastomer.

[0021] The first thermoplastic elastomer layer is a layer containing a thermoplastic elastomer. Hereinafter, the thermoplastic elastomer contained in the first thermoplastic elastomer layer will also be referred to as thermoplastic elastomer (E1). From the viewpoint of effectively exerting the advantages of the present invention, the content of the thermoplastic elastomer (E1) in the first thermoplastic elastomer layer is preferably 90% by weight or more, more preferably 95% by weight or more, even more preferably 98% by weight or more, and particularly preferably 99% by weight or more, and is usually 100% by weight or less, and may be 100% by weight.

[0022] The thermoplastic elastomer (E1) and the thermoplastic elastomer (E2) described below usually contain a polymer and optional components that may be contained as needed. The polymer that may be contained in the thermoplastic elastomer may be a copolymer, or a mixture (polymer blend) of homopolymers or copolymers. Examples of the thermoplastic elastomer include amide-based thermoplastic elastomers, ester-based thermoplastic elastomers, olefin-based thermoplastic elastomers, aromatic vinyl compound-conjugated diene-based thermoplastic elastomers (e.g., styrene-based thermoplastic elastomers), urethane-based thermoplastic elastomers, and crosslinked thermoplastic rubbers. The thermoplastic elastomers may be used singly or in combination of two or more.

[0023] The thermoplastic elastomer (E1) contained in the first thermoplastic elastomer layer is preferably an aromatic vinyl compound-conjugated diene thermoplastic elastomer. The term "aromatic vinyl compound-conjugated diene thermoplastic elastomer" refers to a block copolymer having a polymer block (A) primarily composed of aromatic vinyl compound units and a polymer block (B) primarily composed of linear conjugated diene compound units; a hydrogenated version of the block copolymer; a modified version of the block copolymer or the hydrogenated version of the block copolymer; and combinations thereof. Examples of modified versions include those obtained by modifying the block copolymer or the hydrogenated version of the block copolymer with a modifying component such as an alkoxysilane, a carboxylic acid, or a carboxylic acid anhydride. Hereinafter, a block copolymer having the polymer block (A) and the polymer block (B) is also referred to as a specific block copolymer. In addition, the specific block copolymer and the hydrogenated product of the specific block copolymer are collectively referred to as a specific block copolymer, etc.

[0024] The specific block copolymer having a polymer block (A) mainly composed of aromatic vinyl compound units and a polymer block (B) mainly composed of linear conjugated diene compound units is also referred to as an aromatic vinyl compound-conjugated diene block copolymer, and a hydrogenated product of the specific block copolymer is also referred to as a hydrogenated aromatic vinyl compound-conjugated diene block copolymer.

[0025] The term "aromatic vinyl compound unit" refers to a structural unit having a structure formed by polymerizing an aromatic vinyl compound. The term "chain conjugated diene compound unit" refers to a structural unit having a structure formed by polymerizing a chain conjugated diene compound. The chain conjugated diene compound may be linear or branched. In a polymer block, a unit that is the main component means a unit that is contained in an amount of 50% by weight or more, with the polymer block being 100% by weight.

[0026] Examples of aromatic vinyl compounds corresponding to the aromatic vinyl compound unit include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, 4-monochlorostyrene, dichlorostyrene, 4-monofluorostyrene, and 4-phenylstyrene. These may be used alone or in combination of two or more in any ratio. Among these, those not containing polar groups are preferred in terms of hygroscopicity. Furthermore, styrene is particularly preferred in terms of industrial availability and impact resistance.

[0027] The content of aromatic vinyl compound units in the polymer block (A) is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 99% by weight or more. By increasing the amount of aromatic vinyl compound units in the polymer block (A) as described above, the heat resistance of the thermoplastic elastomer can be improved.

[0028] The polymer block (A) may contain any structural unit other than the aromatic vinyl compound unit, such as a chain conjugated diene compound unit or a structural unit having a structure formed by polymerizing a vinyl compound other than an aromatic vinyl compound.

[0029] Examples of the chain conjugated diene compound corresponding to the chain conjugated diene compound unit include the same examples as those given as examples of the chain conjugated diene compound corresponding to the chain conjugated diene compound unit contained in the polymer block (B). The chain conjugated diene compound may be used alone or in combination of two or more types in any ratio.

[0030] Examples of vinyl compounds other than aromatic vinyl compounds include linear vinyl compounds; cyclic vinyl compounds; vinyl compounds having a nitrile group, an alkoxycarbonyl group, a hydroxycarbonyl group, or a halogen group; unsaturated cyclic acid anhydrides; and unsaturated imide compounds. Among these, linear olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-eicosene, 4-methyl-1-pentene, and 4,6-dimethyl-1-heptene; and cyclic olefins such as vinylcyclohexane, which do not contain polar groups, are preferred in terms of hygroscopicity. Among these, linear olefins are more preferred, with ethylene and propylene being particularly preferred. These may be used alone or in combination of two or more in any ratio.

[0031] The content of any structural unit in the polymer block (A) is preferably 10% by weight or less, more preferably 5% by weight or less, particularly preferably 1% by weight or less, and is usually 0% by weight or more, and may be 0% by weight.

[0032] The number of polymer blocks (A) in one molecule of the specific block copolymer is preferably 2 or more, and preferably 5 or less, more preferably 4 or less, and particularly preferably 3 or less. The multiple polymer blocks (A) present in one molecule may be the same or different from each other.

[0033] The polymer block (B) of the specific block copolymer has a chain conjugated diene compound unit. Examples of the chain conjugated diene compound corresponding to the chain conjugated diene compound unit of this polymer block (B) include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. These may be used alone or in combination of two or more in any ratio. Among these, those not containing a polar group are preferred in terms of hygroscopicity, and 1,3-butadiene and isoprene are particularly preferred.

[0034] The content of the linear conjugated diene compound units in the polymer block (B) is preferably 90% by weight or more, more preferably 95% by weight or more, and particularly preferably 99% by weight or more. By increasing the amount of the linear conjugated diene compound units in the polymer block (B) as described above, the impact resistance at low temperatures of the thermoplastic elastomer can be improved.

[0035] The polymer block (B) may contain any structural unit other than the chain conjugated diene compound unit. Examples of the any structural unit include an aromatic vinyl compound unit and a structural unit having a structure formed by polymerizing a vinyl compound other than an aromatic vinyl compound. Examples of the aromatic vinyl compound unit and the structural unit having a structure formed by polymerizing a vinyl compound other than an aromatic vinyl compound include the units exemplified as those that may be contained in the polymer block (A).

[0036] The content of any structural unit in the polymer block (B) is preferably 10% by weight or less, more preferably 5% by weight or less, particularly preferably 1% by weight or less, and is usually 0% by weight or more, and may even be 0% by weight. In particular, by reducing the content of the aromatic vinyl compound unit in the polymer block (B), the flexibility of the thermoplastic elastomer layer at low temperatures can be improved, and the impact resistance of the thermoplastic elastomer layer at low temperatures can be improved.

[0037] The number of polymer blocks (B) in one molecule of the specific block copolymer is usually at least 1, but may be at least 2. When the number of polymer blocks (B) in the specific block copolymer is at least 2, the polymer blocks (B) may be the same as or different from each other.

[0038] The block form of the specific block copolymer may be a chain type block or a radial type block, of which the chain type block is preferred because it has excellent mechanical strength. When the specific block copolymer has a chain-type block form, it is preferable that both ends thereof are polymer blocks (A), since this makes it possible to suppress the stickiness of the thermoplastic elastomer to a desired low value.

[0039] Particularly preferred block forms of the specific block copolymer are a triblock copolymer in which polymer block (A) is bonded to both ends of polymer block (B), as represented by (A)-(B)-(A), or a pentablock copolymer in which polymer block (B) is bonded to both ends of polymer block (A), and polymer block (A) is bonded to the other end of each of the polymer blocks (B), as represented by (A)-(B)-(A)-(B)-(A). In particular, a triblock copolymer of (A)-(B)-(A) is particularly preferred because it is easy to produce and physical properties such as viscosity can be adjusted to desired ranges.

[0040] In the specific block copolymer, the ratio (wA / wB) of the weight fraction (wA) of all polymer blocks (A) in the entire specific block copolymer to the weight fraction (wB) of all polymer blocks (B) in the entire specific block copolymer is preferably 30 / 70 or more, more preferably 40 / 60 or more, even more preferably 45 / 55 or more, and preferably 80 / 20 or less, more preferably 70 / 30 or less, and even more preferably 55 / 45 or less. By setting the ratio (wA / wB) at or above the lower limit of the above range, the heat resistance of the thermoplastic elastomer can be improved. On the other hand, by setting it at or below the upper limit, the flexibility of the thermoplastic elastomer can be increased, thereby maintaining a stable and excellent sealing ability of the thermoplastic elastomer. Furthermore, by lowering the glass transition temperature of the block copolymer, the sealing temperature can be lowered, thereby suppressing thermal degradation of the object to be sealed.

[0041] The weight average molecular weight (Mw) of the specific block copolymer is preferably 30,000 or more, more preferably 40,000 or more, particularly preferably 50,000 or more, and preferably 200,000 or less, more preferably 150,000 or less, particularly preferably 100,000 or less. The molecular weight distribution (Mw / Mn) of the specific block copolymer is preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and preferably 1.0 or more, where Mn represents the number average molecular weight. The weight average molecular weight and molecular weight distribution of a specific block copolymer can be measured as polystyrene equivalent values ​​by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0042] The hydrogenated product of the specific block copolymer is obtained by hydrogenating the unsaturated bonds of the specific block copolymer described above. Here, the unsaturated bonds of the block copolymer include both aromatic and non-aromatic carbon-carbon unsaturated bonds in the main chain and side chain of the block copolymer. The hydrogenation rate is preferably 90% or more, more preferably 97% or more, and particularly preferably 99% or more of the total unsaturated bonds of the block copolymer. The higher the hydrogenation rate, the better the heat resistance and light resistance of the thermoplastic elastomer. Here, the hydrogenation rate of the hydrogenated product is 1 It can be determined by measurement using H-NMR.

[0043] In particular, the hydrogenation rate of non-aromatic unsaturated bonds is preferably 95% or more, more preferably 99% or more. By increasing the hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds, the light resistance and oxidation resistance of the thermoplastic elastomer can be further improved.

[0044] The hydrogenation rate of the aromatic carbon-carbon unsaturated bonds is preferably 90% or higher, more preferably 93% or higher, and particularly preferably 95% or higher. Increasing the hydrogenation rate of the aromatic carbon-carbon unsaturated bonds increases the glass transition temperature of the polymer block obtained by hydrogenating polymer block (A), thereby effectively improving the heat resistance of the thermoplastic elastomer. Furthermore, the photoelastic coefficient of the thermoplastic elastomer can be reduced, thereby suppressing the occurrence of unintended retardation during encapsulation.

[0045] The weight-average molecular weight (Mw) of the hydrogenated specific block copolymer is preferably 30,000 or more, more preferably 40,000 or more, particularly preferably 45,000 or more, and preferably 200,000 or less, more preferably 150,000 or less, and particularly preferably 100,000 or less. The molecular weight distribution (Mw / Mn) of the hydrogenated specific block copolymer is preferably 3 or less, more preferably 2 or less, particularly preferably 1.5 or less, and preferably 1.0 or more. By ensuring that the weight-average molecular weight Mw and molecular weight distribution Mw / Mn of the hydrogenated specific block copolymer fall within the above ranges, the mechanical strength and heat resistance of the thermoplastic elastomer can be improved. The weight-average molecular weight and molecular weight distribution of the hydrogenated block copolymer can be measured in polystyrene equivalent terms by gel permeation chromatography using tetrahydrofuran as a solvent.

[0046] In the hydrogenated product of the specific block copolymer, the ratio (wA / wB) of the weight fraction wA of all polymer blocks (A) in the entire specific block copolymer to the weight fraction wB of all polymer blocks (B) in the entire specific block copolymer is usually the same value as the ratio wA / wB in the specific block copolymer before hydrogenation.

[0047] Specific examples of modified specific block copolymers or hydrogenated specific block copolymers include those modified with silicon atom-containing polar groups. Examples of silicon atom-containing polar groups include alkoxysilyl groups. Modified specific block copolymers with alkoxysilyl groups can be obtained by bonding alkoxysilyl groups to the specific block copolymer or its hydrogenated product. In this case, the alkoxysilyl groups may be bonded directly to the specific block copolymer or its hydrogenated product, or may be bonded via a divalent organic group such as an alkylene group.

[0048] An example of a method for bonding an alkoxysilyl group to the specific block copolymer or a hydride thereof is to react the specific block copolymer or a hydride thereof with an ethylenically unsaturated silane compound in the presence of a peroxide.

[0049] The ethylenically unsaturated silane compound can be one that can be graft polymerized with a specific block copolymer, etc., and that can introduce an alkoxysilyl group into the specific block copolymer, etc. Examples of such ethylenically unsaturated silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, p-styryltrimethoxysilane, p-styryltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and 2-norbornene-5-yltrimethoxysilane. Among these, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, and p-styryltrimethoxysilane are preferred. The ethylenically unsaturated silane compounds may be used alone or in combination of two or more in any ratio.

[0050] The amount of the ethylenically unsaturated silane compound is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, and particularly preferably 0.3 parts by weight or more, relative to 100 parts by weight of the specific block copolymer before the introduction of the alkoxysilyl group, and is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and particularly preferably 3 parts by weight or less.

[0051] As the peroxide, for example, the peroxides described in International Publication No. 2016 / 153030 (Patent Document 1) can be used.

[0052] Among aromatic vinyl compound-conjugated diene thermoplastic elastomers, the thermoplastic elastomer (E1) contained in the first thermoplastic elastomer layer is preferably one or more selected from the group consisting of aromatic vinyl compound-conjugated diene block copolymers and hydrogenated aromatic vinyl compound-conjugated diene block copolymers, with hydrogenated aromatic vinyl compound-conjugated diene block copolymers being more preferred. These block copolymers have low affinity with resins that may be contained in the release sheet, allowing the release sheet to be easily peeled from the first thermoplastic elastomer layer with an appropriate force. Furthermore, the storage modulus at 23°C of these block copolymers can be adjusted by changing the weight ratio of the polymer block (A) and the polymer block (B) contained therein.

[0053] The thermoplastic elastomer (E1) may contain optional components in addition to the polymer as described above. The content of the polymer in the thermoplastic elastomer (E1) is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 97% by weight or more, even more preferably 98% by weight or more, and usually 100% by weight or less. Examples of optional components include plasticizers, light stabilizers such as hindered amine light stabilizers, ultraviolet absorbers such as benzophenone ultraviolet absorbers, salicylic acid ultraviolet absorbers, and benzotriazole ultraviolet absorbers, antioxidants such as phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants, lubricants, fillers, and colorants such as pigments and dyes. One type of optional component may be used alone, or two or more types may be used in combination in any ratio.

[0054] Examples of plasticizers include polyisobutene, hydrogenated polyisobutene, hydrogenated polyisoprene, hydrogenated 1,3-pentadiene petroleum resin, hydrogenated cyclopentadiene petroleum resin, hydrogenated styrene-indene petroleum resin, etc. One type of plasticizer may be used alone, or two or more types may be used in any combination in any ratio. The content of the plasticizer in the thermoplastic elastomer (E1) is preferably 20% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, and even more preferably 3% by weight or less, and is usually 0% by weight or more, and may be 0% by weight.

[0055] The thickness of the first thermoplastic elastomer layer is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more from the viewpoint of effectively exerting the sealing function, and is preferably 800 μm or less, more preferably 500 μm or less, and even more preferably 200 μm or less from the viewpoint of improving optical properties such as transparency.

[0056] The first thermoplastic elastomer layer preferably has transparency, and specifically, the total light transmittance of the first thermoplastic elastomer layer is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and is usually 100% or less. The internal haze of the first thermoplastic elastomer layer is preferably 1% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The good transparency of the first thermoplastic elastomer increases the linearity of light passing through the layer, and this can improve the visibility of the sealed object such as an optical device and the linearity of light passing through the sealed object. The total light transmittance and internal haze of the first thermoplastic elastomer layer are values ​​measured for a laminate having a layer structure of glass substrate / first thermoplastic elastomer layer / glass substrate, assuming that the total light transmittance, haze, and internal haze of the glass substrate are 100%, 0%, and 0%, respectively. The total light transmittance and internal haze of the second thermoplastic elastomer layer can be measured in the same manner as for the first thermoplastic elastomer layer.

[0057] The total light transmittance can be measured in accordance with JIS K7361-1 using an ultraviolet-visible spectrometer in the wavelength range of 400 nm to 700 nm. The internal haze can be measured using a haze meter in accordance with K7136. The total light transmittance and internal haze of the second thermoplastic elastomer layer can be measured in the same manner.

[0058] (Release sheet) The release sheet is a sheet that is laminated to the first thermoplastic elastomer layer and has a peel strength of typically 3 N / 10 mm or less when peeling off the first thermoplastic elastomer layer, preferably 2 N / 10 mm or less, more preferably 1 N / 10 mm or less, and even more preferably 0.5 N / 10 mm or less. The lower limit of the peel strength is usually 0.005 N / 10 mm or more, preferably 0.01 N / 10 mm or more, and more preferably 0.02 N / 10 mm or more. The peel strength is the tensile load per 10 mm of sample width when the release sheet of a laminate comprising a release sheet and a first thermoplastic elastomer layer is fixed and the first thermoplastic elastomer layer is pulled in a 90-degree direction at a rate of 300 mm / min. If the thermoplastic elastomer is thin and stretches when pulled, making it impossible to measure the peel strength, the release sheet, the first thermoplastic elastomer layer, and an aluminum foil or polyethylene terephthalate (PET) substrate with a thickness of 20 μm or less may be laminated to form a three-layer laminate, and the first thermoplastic elastomer layer and the aluminum foil or PET substrate are pulled in a 90-degree direction together to measure the peel strength. Peel strength can be measured using a testing device such as the FSA series manufactured by Imada Corporation or the AGS-X manufactured by Shimadzu Corporation.

[0059] The arithmetic mean roughness Ra of the first main surface of the release sheet is preferably 10 nm or less, more preferably 5 nm or less, and usually 0 nm or more. Here, the first main surface of the release sheet refers to the main surface, of the two main surfaces of the release sheet, that is in contact with the first thermoplastic elastomer layer. When the arithmetic mean roughness Ra of the first main surface of the release sheet is equal to or less than the upper limit, the surface roughness of the first thermoplastic elastomer layer can be reduced even if the surface shape of the release sheet is transferred to the first thermoplastic elastomer layer. As a result, the surface haze of the first thermoplastic elastomer layer can be effectively reduced, and the first thermoplastic elastomer layer is prevented from becoming cloudy. As a result, the influence of the first thermoplastic elastomer layer on the optical properties of the encapsulated product can be reduced.

[0060] The arithmetic mean roughness Ra of the first main surface of the release sheet can be measured by a surface roughness meter such as a stylus surface roughness meter.

[0061] The thickness of the release sheet is usually 150 μm or more, preferably 200 μm or more, more preferably 300 μm or more from the viewpoint of reducing dents on the first thermoplastic elastomer layer, and is preferably 1 mm or less, more preferably 800 μm or less, and even more preferably 700 μm or less from the viewpoint of ease of rolling up when made into a long encapsulating sheet. From the viewpoint of reducing the difference in thickness between the central part and the peripheral end part of the first thermoplastic elastomer layer in the encapsulated product, the thickness of the release sheet is preferably more than 200 μm, more preferably 300 μm or more.

[0062] The ratio of the thickness of the release sheet to the thickness of the first thermoplastic elastomer layer (release sheet / first thermoplastic elastomer layer) is preferably 0.4 or more, more preferably 3 or more, from the viewpoint of effectively reducing dents in the first thermoplastic elastomer layer, and is preferably 30 or less, more preferably 25 or less, and even more preferably 20 or less, from the viewpoint of facilitating peeling of the release sheet.

[0063] The release sheet may be a sheet containing glass, metal, or resin. However, from the viewpoint of being able to form a roll, it is preferable that the release sheet contains a resin. Examples of resins that can be contained in the release sheet include vinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride; polyimide resins; polycarbonate resins; acrylic resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; poly(α-olefin) resins such as polyethylene, polypropylene, and polymethylpentene; cyclic olefin resins such as norbornene-based polymers; and fluororesins such as poly(tetrafluoroethylene). The polymers contained in these resins may be homopolymers or copolymers. These resins may be used alone or in combination of two or more in any ratio.

[0064] Here, polyimide resin refers to a resin containing a polymer whose repeating unit contains an imide structure (-(C=O)-(NR)-(C=O)-: R represents a hydrogen atom or a substituent such as an aryl group). Polycarbonate resin refers to a resin containing a polymer whose repeating unit contains a carbonate structure (-O-(C=O)-O-). Acrylic resin refers to a resin containing a polymer containing a repeating unit having a structure obtained by polymerizing (meth)acrylic acid or a derivative thereof. Examples of (meth)acrylic acid derivatives include (meth)acrylic acid esters such as methyl methacrylate; (meth)acrylamide; and (meth)acrylonitrile.

[0065] The release sheet preferably contains one or more resins selected from the group consisting of vinyl chloride resin, polyimide resin, polycarbonate resin, and acrylic resin; from the viewpoint of reducing warpage due to heating, it more preferably contains one or more resins selected from the group consisting of vinyl chloride resin, polyimide resin, and polycarbonate resin. These resins have polar groups and therefore have low affinity with thermoplastic elastomers with low polarity (for example, the above-mentioned specific block copolymers), making it easy to peel the release sheet from the first thermoplastic elastomer layer with an appropriate force.

[0066] The resin that can be contained in the release sheet may contain optional components in addition to the polymer. The polymer content in the release sheet is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, and is usually 100% by weight or less. Examples of optional components that can be contained in the resin include plasticizers, light stabilizers, ultraviolet absorbers, antioxidants, lubricants, and fillers. One type of optional component may be used alone, or two or more types may be used in combination at any ratio.

[0067] The release sheet may have a single-layer structure or a multi-layer structure. In a preferred embodiment, the release sheet has a single-layer structure and contains a resin. In another preferred embodiment, the release sheet has a multi-layer structure and includes a base layer and a release layer having releasability. More preferably, the release sheet includes a substrate layer and a release layer provided on a main surface of the substrate layer. The release layer may be provided on only one main surface of the substrate layer, or on each of the two main surfaces. Furthermore, when a plurality of release layers are provided on the substrate layer, the plurality of release layers may differ from each other in properties such as the components contained, the amount of components, and thickness. For example, the release layers that can be provided on each of the two main surfaces of the substrate layer may differ from each other in any of the components contained, the amount of components, and thickness.

[0068] The release layer may be formed from a material having releasability. The material having releasability is not particularly limited, and a material containing a known release agent may be appropriately selected. Examples of the release agent include silicone-based release agents and non-silicone-based release agents such as polyolefins.

[0069] Examples of materials for forming the base layer include the resins listed as examples of the resin contained in the release sheet.

[0070] Examples of commercially available release sheets include "Cosmo Peel (registered trademark)" manufactured by Toyobo Co., Ltd., "Therapeel (registered trademark)" manufactured by Toray Advanced Film Co., Ltd., and "Clean Sepa (registered trademark)" manufactured by Higashiyama Film Co., Ltd.

[0071] (any layer) The encapsulating sheet may include any optional layer in addition to the release sheet and the first thermoplastic elastomer layer. An example of an optional layer is a second thermoplastic elastomer layer, which is a thermoplastic elastomer layer separate from the first thermoplastic elastomer layer. The second thermoplastic elastomer layer is a layer containing a thermoplastic elastomer. Hereinafter, the thermoplastic elastomer contained in the second thermoplastic elastomer layer will also be referred to as thermoplastic elastomer (E2). The encapsulating sheet preferably includes a release sheet, a first thermoplastic elastomer layer, and a second thermoplastic elastomer layer in this order. In other words, the first thermoplastic elastomer layer is preferably disposed between the second thermoplastic elastomer layer and the release sheet. The first thermoplastic elastomer layer and the second thermoplastic elastomer layer contain different thermoplastic elastomers. Here, thermoplastic elastomers that differ from each other in at least one of the following properties can be called different thermoplastic elastomers: polymer structure or composition, such as the type of structural unit constituting the polymer contained in the thermoplastic elastomer, the weight ratio of the structural units, the weight ratio of multiple polymer blocks constituting the polymer contained, and the bonding mode of the polymer blocks; weight average molecular weight of the polymer; and physical properties of the thermoplastic elastomer, such as storage modulus at 23°C.

[0072] The content of the thermoplastic elastomer (E2) in the second thermoplastic elastomer layer is preferably 90% by weight or more, more preferably 95% by weight or more, even more preferably 98% by weight or more, and particularly preferably 99% by weight or more, from the viewpoint of effectively exhibiting the characteristics of the thermoplastic elastomer (E2) in the second thermoplastic elastomer layer, and is usually 100% by weight or less, and may be 100% by weight.

[0073] Examples of the thermoplastic elastomer (E2) include the examples of the thermoplastic elastomers mentioned above. The thermoplastic elastomer (E2) contained in the second thermoplastic elastomer layer is preferably at least one selected from the group consisting of aromatic vinyl compound-conjugated diene block copolymers modified with a silicon atom-containing polar group and hydrogenated aromatic vinyl compound-conjugated diene block copolymers modified with a silicon atom-containing polar group, and more preferably hydrogenated aromatic vinyl compound-conjugated diene block copolymers modified with a silicon atom-containing polar group.

[0074] These modified products are modified with a polar silicon atom-containing polar group, and therefore have improved affinity with polar materials (e.g., metals), and can effectively improve the adhesion between the second thermoplastic elastomer layer of the encapsulating sheet and an object to be encapsulated, including a polar material.

[0075] The thermoplastic elastomer (E2) may contain optional components in addition to the polymer. The content of the polymer in the thermoplastic elastomer (E2) is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 97% by weight or more, even more preferably 98% by weight or more, and usually 100% by weight or less. Examples of optional components that can be contained in the thermoplastic elastomer (E2) include the same examples as the optional components that can be contained in the thermoplastic elastomer (E1). One type of optional component may be used alone, or two or more types may be used in combination in any ratio.

[0076] The thickness of the second thermoplastic elastomer layer is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more from the viewpoint of effectively exerting the sealing function, and is preferably 800 μm or less, more preferably 400 μm or less, and even more preferably 100 μm or less from the viewpoint of improving optical properties such as transparency.

[0077] The second thermoplastic elastomer layer preferably has transparency, and specifically, the total light transmittance of the second thermoplastic elastomer layer is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and is usually 100% or less. The internal haze of the second thermoplastic elastomer layer is preferably 1% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The good transparency of the second thermoplastic elastomer increases the linearity of light passing through the layer, and this can improve the visibility of the sealed object such as an optical device and the linearity of light passing through the sealed object.

[0078] The encapsulating sheet may be in a long form or in a sheet form, and is preferably in a long form since it can be produced continuously.

[0079] <2. Example of encapsulating sheet configuration> Hereinafter, an encapsulating sheet according to an embodiment of the present invention will be described with reference to the drawings.

[0080] (Embodiment 1) FIG. 1 is a cross-sectional view schematically showing an encapsulating sheet according to a first embodiment of the present invention. 1 , the encapsulating sheet 100 of embodiment 1 includes a release sheet 110 and a layer 120 as a first thermoplastic elastomer layer. The release sheet 110 has a main surface 110U and a main surface 110D, and the layer 120 is provided in contact with the main surface 110D. In this embodiment, the main surface 120U of the layer 120 is directly in contact with the main surface 110D of the release sheet 110. That is, there is no layer between the release sheet 110 and the layer 120. From the viewpoint of effectively reducing the occurrence of dents in the layer that directly contacts the release sheet, it is preferable that layer 120 be directly on main surface 110D of release sheet 110, and that no layer be present between release sheet 110 and layer 120, as in this embodiment.

[0081] The sealing sheet of the present embodiment includes the release sheet 110 and the layer 120 which is the first thermoplastic elastomer layer, and thus can reduce the occurrence of dents in the first thermoplastic elastomer layer.

[0082] (Embodiment 2) FIG. 2 is a cross-sectional view schematically showing an encapsulating sheet according to a second embodiment of the present invention. 2 , the encapsulating sheet 200 of the second embodiment includes a release sheet 110, a layer 120 as a first thermoplastic elastomer layer, and a layer 230 as a second thermoplastic elastomer layer, in this order in the thickness direction of the encapsulating sheet 200. In this embodiment, similar to the first embodiment, the main surface 120U of the layer 120 is directly connected to the main surface 110D of the release sheet 110. That is, no layer is present between the release sheet 110 and the layer 120. In this embodiment, the main surface 120D of the layer 120 and the main surface 230U of the layer 230 are directly connected to each other. That is, there is no other layer between the layer 120 and the layer 230. In another embodiment, an optional layer such as an adhesive layer may be present between the first thermoplastic elastomer layer and the second thermoplastic elastomer layer. However, from the viewpoint of improving the optical properties of the encapsulating sheet, such as transparency, it is preferable that the layer 230 is directly connected to the main surface 120D of the layer 120, and that no optional layer is present between the layer 120 and the layer 230, as in the present embodiment.

[0083] The encapsulating sheet of the present embodiment can reduce the occurrence of dents in the first thermoplastic elastomer layer by including the release sheet 110 and the layer 120 which is the first thermoplastic elastomer layer, and in addition, by including the layer 230 which is the second thermoplastic elastomer layer, the encapsulating sheet 200 can be given properties according to the properties of the layer 230. For example, by forming the layer 130 from a material which has excellent adhesion to the object to be encapsulated, the sealing property of the encapsulating sheet 200 can be improved.

[0084] <3. Manufacturing method of encapsulating sheet> The encapsulating sheet can be produced by any method. For example, a release sheet is prepared, and a liquid composition containing a thermoplastic elastomer (E1) is applied to a main surface (first main surface) of the release sheet by a conventionally known method to obtain a layer of the liquid composition, and the layer of the liquid composition is dried as necessary, thereby obtaining an encapsulating sheet including the release sheet and the first thermoplastic elastomer layer provided in contact with the first main surface of the release sheet. Alternatively, a sealing sheet including a release sheet and the first thermoplastic elastomer layer may be obtained by melting and extruding the thermoplastic elastomer (E1) to form a first thermoplastic elastomer layer, and laminating the first thermoplastic elastomer layer with a release sheet. The lamination of the first thermoplastic elastomer layer and the release sheet is not particularly limited, and can be performed, for example, by bonding the first thermoplastic elastomer layer and the release sheet together before the extruded first thermoplastic elastomer layer is cooled to room temperature.

[0085] Examples of the method for applying the liquid composition containing the thermoplastic elastomer (E1) to the first main surface of the release sheet are not particularly limited, and include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating methods such as screen printing and inkjet printing, gravure coating, die coating, and gap coating.

[0086] The liquid composition containing the thermoplastic elastomer (E1) may be prepared, for example, by heating a composition containing the thermoplastic elastomer (E1) to a temperature equal to or higher than the glass transition temperature of the thermoplastic elastomer (E1) to melt it, or by dissolving or dispersing the thermoplastic elastomer (E1) and any optional components in a solvent to prepare the liquid composition.

[0087] Examples of solvents that can be contained in the liquid composition include alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbon solvents such as toluene; cyclic ether solvents such as tetrahydrofuran; and aliphatic hydrocarbon solvents such as decane and dodecane. The solvents may be used alone or in combination of two or more in any ratio.

[0088] When the liquid composition contains a solvent, from the viewpoint of easily obtaining a first thermoplastic elastomer layer of the desired thickness, the weight proportion of the thermoplastic elastomer (E1) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, and is preferably 100 parts by weight or less, more preferably 90 parts by weight or less, even more preferably 80 parts by weight or less, relative to 100 parts by weight of the solvent.

[0089] Examples of methods for drying the layer of the liquid composition include natural drying, heat drying, vacuum drying, and heat-vacuum drying.

[0090] When the encapsulating sheet includes a release sheet, a first thermoplastic elastomer layer, and a second thermoplastic elastomer layer in this order, the encapsulating sheet can be produced, for example, by bonding the second thermoplastic elastomer layer to a first laminate including a release sheet and a first thermoplastic elastomer layer provided in contact with a first main surface of the release sheet so as to face and be in contact with the first thermoplastic elastomer layer.

[0091] The second thermoplastic elastomer layer can be obtained, for example, by preparing a substrate, applying a liquid composition containing the thermoplastic elastomer (E2) to the main surface of the substrate by a conventionally known method to obtain a layer of the liquid composition, and drying the layer of the liquid composition as necessary.

[0092] A second laminate including a substrate and a second thermoplastic elastomer layer may be attached to the first laminate so that the first thermoplastic elastomer layer and the second thermoplastic elastomer layer face each other, and then the substrate is peeled off from the second thermoplastic elastomer layer, thereby producing an encapsulating sheet including a release sheet, the first thermoplastic elastomer layer, and the second thermoplastic elastomer layer in this order.

[0093] <4. Applications of encapsulating sheets> The encapsulating sheet can be used to encapsulate an object. Since the dents that may occur in the first thermoplastic elastomer layer during the encapsulation process are reduced, the encapsulating sheet can be suitably used to encapsulate an object that requires transparency. Examples of objects to be encapsulated include electrodes of transparent devices such as touch panels and transparent antennas, displays such as micro LEDs, perovskite solar cell electrodes, and optical elements such as light-receiving sensors. Electrodes used in transparent devices such as touch panels are preferred. Therefore, the encapsulating sheet can be an encapsulating sheet for transparent devices such as touch panels, and more specifically, an encapsulating sheet for electrodes used in transparent devices. A transparent device refers to a device that is transparent and typically has a total light transmittance of 30% or more. The total light transmittance can be measured using an ultraviolet-visible spectrometer in a wavelength range of 400 nm to 700 nm.

[0094] A touch panel is an input device provided on an image display device that allows a user to input information by touching a specified location while referring to an image displayed on the display surface of the image display device as needed. Examples of the touch panel type include a capacitance type, an optical type, an ultrasonic type, an electromagnetic induction type, and a resistive film type, and the capacitance type, an optical type, or a resistive film type is preferred.

[0095] The image display system of the image display device provided with the touch panel is not particularly limited, and any display system such as a liquid crystal display device or an organic electroluminescence display device can be adopted.

[0096] The touch panel electrode may be, for example, an electrode layer containing at least one conductive material selected from the group consisting of conductive metal oxides, conductive nanowires, metal meshes, and conductive polymers. The electrode layer may have the conductive material disposed over the entire in-plane direction of the electrode layer, or the conductive material may be patterned into a predetermined pattern. The pattern shape of the electrode layer is preferably a pattern that allows good operation as a touch panel (e.g., a capacitive touch panel), and examples thereof include the patterns described in JP-A 2011-511357, JP-A 2010-164938, JP-A 2008-310550, JP-A 2003-511799, and JP-A 2010-541109.

[0097] Examples of conductive metal oxides include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), IWO (indium tungsten oxide), ITiO (indium titanium oxide), AZO (aluminum zinc oxide), GZO (gallium zinc oxide), XZO (zinc-based special oxide), and IGZO (indium gallium zinc oxide). Among these, ITO is particularly preferred from the viewpoints of light transmittance and durability. These may be used alone or in combination of two or more in any ratio.

[0098] Conductive nanowires are needle- or thread-shaped conductive materials with nanometer-sized diameters. Conductive nanowires may be straight or curved. Such conductive nanowires form a mesh-like structure with gaps between them, allowing even a small amount of conductive nanowires to form good electrical conduction paths, thereby realizing an electrode layer with low electrical resistance. Furthermore, the mesh-like structure of the conductive nanowires creates openings in the gaps between the meshes, allowing an electrode layer with high light transmittance to be obtained. Furthermore, the use of an electrode layer containing conductive nanowires typically allows a laminate with excellent flex resistance to be obtained.

[0099] The thickness of the conductive nanowires is preferably less than 500 nm, more preferably less than 200 nm, still more preferably 10 to 100 nm, and particularly preferably 10 to 50 nm, which can increase the transparency of the electrode layer.

[0100] The length of the conductive nanowires is preferably 2.5 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 20 μm to 100 μm, which can increase the conductivity of the electrode layer.

[0101] Examples of conductive nanowires include metal nanowires made of metal (eg, silver nanowires) and conductive nanowires containing carbon nanotubes, with metal nanowires being preferred.

[0102] The metal mesh is a thin metal wire formed in a lattice pattern. The metal contained in the metal mesh is preferably a metal with high conductivity. Examples of suitable metals include gold, platinum, silver, and copper, with silver, copper, and gold being preferred, and silver being more preferred. These metals may be used alone or in combination of two or more in any ratio.

[0103] Examples of conductive polymers include polythiophene-based polymers, polyacetylene-based polymers, polyparaphenylene-based polymers, polyaniline-based polymers, polyparaphenylenevinylene-based polymers, polypyrrole-based polymers, polyphenylene-based polymers, and polyester-based polymers modified with acrylic polymers. The conductive polymers may be used singly or in combination of two or more kinds in any ratio. For electrode layers containing conductive polymers, reference may be made to JP 2011-175601 A.

[0104] The light transmittance of the electrode layer in the wavelength range of 400 nm to 700 nm is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more, and is usually 100% or less, and may be 100%.

[0105] The thickness of the electrode layer is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 3 μm, and particularly preferably 0.1 μm to 1 μm.

[0106] <5. Method for manufacturing electrode laminate> The encapsulating sheet can be used to produce an electrode laminate including a first thermoplastic elastomer layer and an electrode layer. The electrode laminate can be suitably used as a component of a touch panel, for example. A method for producing an electrode stack according to one embodiment of the present invention includes the steps of: Step (1) of overlaying the encapsulating sheet on an electrode layer to form an intermediate laminate including the release sheet, the first thermoplastic elastomer layer, and the electrode layer in this order; Step (2) of pressing the intermediate laminate; and a step (3) of peeling the release sheet from the pressed intermediate laminate to form an electrode laminate; Includes. According to the method for producing an electrode laminate using the sealing sheet, it is possible to obtain an electrode laminate in which dents on the surface that may be caused by pressurizing an intermediate laminate are reduced. The surface of the electrode laminate may be the surface of the first thermoplastic elastomer layer.

[0107] Steps (1), (2), and (3) are usually carried out in this order. The method for producing an electrode laminate may include any optional step in addition to steps (1) to (3).

[0108] (Process (1)) In the step (1), the electrode layer on which the encapsulating sheet is superposed may be, for example, the electrode layer for constituting the touch panel electrode. The sealing sheet may be placed over the entire electrode layer, or may be placed over only a portion of the electrode layer. From the viewpoint of effectively sealing the electrode layer, it is preferable to place the sealing sheet over the entire electrode layer. The encapsulating sheet may be laminated on any member such as a substrate, a connector, a semiconductor element, etc. in addition to the electrode layer. When the encapsulating sheet includes a release sheet, a first thermoplastic elastomer layer, and a second thermoplastic elastomer layer in this order in the thickness direction, the encapsulating sheet is usually overlaid on the electrode layer so that the second thermoplastic elastomer layer of the encapsulating sheet contacts the electrode layer in step (1), thereby forming an intermediate laminate including the release sheet, the first thermoplastic elastomer layer, the second thermoplastic elastomer layer, and the electrode layer in this order.

[0109] (Process (2)) In step (2), the intermediate laminate formed in step (1) is pressed. Examples of pressure devices include, but are not limited to, a vacuum laminator that pressurizes a laminate under vacuum to laminate, and a roller laminator that pressurizes a laminate under normal pressure using a roller to laminate. Examples of pressure methods used in vacuum laminators include a roller method, a diaphragm method that pressurizes using a flexible diaphragm, and a vacuum heating and pressing method that presses metal plates against a laminate placed between opposing metal plates while applying heat. The pressure is preferably 0.01 MPa or more, more preferably 0.05 MPa or more, particularly preferably 0.1 MPa or more, and is preferably 1 MPa or less, more preferably 0.75 MPa or less, particularly preferably 0.5 MPa or less.

[0110] Step (2) is preferably carried out in a reduced pressure environment, which effectively prevents water and air from being trapped inside the sealed product. The specific vacuum level of the sealed environment is preferably 1000 Pa or less, more preferably 200 Pa or less, and particularly preferably 100 Pa or less.

[0111] The pressurization time in step (2) is, for example, 1 minute or more, for example, 2 minutes or more, and is, for example, 60 minutes or less, for example, 30 minutes or less.

[0112] Heat may be applied when pressing the intermediate laminate. The heating temperature is preferably Tg-50°C or higher, more preferably Tg-30°C or higher, and preferably Tg+50°C or lower, more preferably Tg+30°C or lower, where Tg represents the glass transition temperature of the first thermoplastic elastomer (E1).

[0113] (Step (3)) In step (3), the release sheet is peeled off from the pressed intermediate laminate to form an electrode laminate. The electrode laminate formed in step (3) includes a first thermoplastic elastomer layer and an electrode layer. When an encapsulating sheet including a release sheet, a first thermoplastic elastomer layer, and a second thermoplastic elastomer layer in this order in the thickness direction is used in step (1), the electrode laminate formed in step (3) includes the first thermoplastic elastomer layer, the second thermoplastic elastomer layer, and an electrode layer in this order in the thickness direction.

[0114] Organic light-emitting elements have lower durability against moisture and oxygen in the environment compared to ordinary electrode layers. Therefore, when sealing organic light-emitting elements, a barrier layer made of a material with low moisture and oxygen permeability, such as an inorganic material, may be superimposed on the sealing layer. On the other hand, when sealing the electrode layer, the durability of the electrode layer is usually higher than that of the organic light-emitting element, and therefore, from the viewpoint of improving the optical properties such as the transparency of the electrode laminate, a release sheet can be peeled off from the first thermoplastic elastomer layer in step (3).

[0115] (Optional process) Examples of optional steps that the manufacturing method of this embodiment may include in addition to steps (1) to (3) include a step of heating the pressurized intermediate laminate and a step of further providing a hard coat layer on the electrode laminate.

[0116] The area of ​​the electrode laminate obtained by the manufacturing method of this embodiment when viewed in the thickness direction is not particularly limited. In one embodiment, the area of ​​the electrode laminate is, for example, 10 cm 2 or more, for example, 25cm 2 or more, for example, 400 cm 2 For example, 250cm 2 It can be the following: In another embodiment, the area of ​​the electrode stack is, for example, 500 cm 2 or more, for example, 1000 cm 2 or more, for example, 40,000 cm 2 For example, 10000 cm 2 The manufacturing method of this embodiment can reduce dents on the surface of even an electrode laminate with such a large area. [Example]

[0117] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the examples shown below, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0118] In the following description, the units "%" and "parts" that represent amounts are by weight unless otherwise specified. Furthermore, the operations described below were carried out at room temperature (20°C ± 15°C) and atmospheric pressure (1 atm) unless otherwise specified.

[0119] <Evaluation method> (Method for measuring the hydrogenation rate of polymer) The hydrogenation rate of the polymer was measured at 145°C using orthodichlorobenzene-d4 as a solvent. 1 Measured by H-NMR measurement.

[0120] (Method for measuring weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polymer) The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer were measured as polystyrene equivalent values ​​using a gel permeation chromatography (GPC) system (Tosoh Corporation, "HLC-8320"). The measurement was performed using an H-type column (Tosoh Corporation) and tetrahydrofuran as the solvent. The temperature during measurement was 40°C.

[0121] (Method for measuring glass transition temperature Tg) The glass transition temperature Tg and the melting point Tm were measured as follows. The sample was melted by heating and then rapidly cooled with dry ice.The glass transition temperature (Tg) of the sample was then measured using a differential scanning calorimeter (DSC) at a heating rate of 10°C / min (heating mode).

[0122] (Tensile elongation and tan δ of thermoplastic elastomer) The tensile elongation at 23°C of the thermoplastic elastomers obtained in the Production Examples was measured in accordance with JIS K7113. The loss tangent tanδ (loss modulus / storage modulus) of the resin at temperatures between 40°C and 200°C was measured by molding the thermoplastic elastomer into a film, cutting out a 10mm wide x 40mm long test piece from the film, and using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation, DMS6100). The measurement conditions were a frequency of 1Hz and a heating rate of 4°C / min.

[0123] (Storage modulus of thermoplastic elastomer) The release sheet was peeled off from the laminate 1 having a layer structure of a first thermoplastic elastomer layer / release sheet produced in each Example and Comparative Example to obtain a thermoplastic elastomer film having a thickness of 50 μm, and a test piece having a width of 10 mm and a length of 40 mm was cut out from the film and measured using a dynamic viscoelasticity measuring device ("DMS6100" manufactured by Hitachi High-Tech Science Corporation). The measurement conditions were a frequency of 1 Hz, a heating rate of 4°C / min, and the storage modulus at 23°C was read.

[0124] (Method for measuring arithmetic mean roughness Ra) Using a surface roughness measuring instrument (Surfcorder ET4000) manufactured by Koito Laboratory Co., Ltd., the arithmetic mean roughness Ra of the main surface of the release sheet was measured under the conditions of a measuring force of 10 μN, a cutoff of 0.008 mm, a measuring speed of 5 μm / s, and λc=5.

[0125] (peel strength) The peel strength between the release sheet and the first thermoplastic elastomer layer was measured by punching out the laminate 1 to a size of 25 x 150 mm, fixing the release sheet of the punched laminate 1, and pulling the first thermoplastic elastomer layer in a 90-degree direction at a speed of 300 mm / min. For thermoplastic elastomer layers as thin as 50 μm to 100 μm and stretching when pulled, resulting in unstable measurements, an 11 μm thick aluminum foil was additionally attached to the laminate 1 consisting of the release sheet and the first thermoplastic elastomer layer, and both the first thermoplastic elastomer layer and the aluminum foil were pulled in a 90-degree direction. The measurement device used was an FSA series manufactured by Imada Co., Ltd.

[0126] (Measurement of total light transmittance and internal haze) Laminate 1 was placed on a glass substrate and bonded using a vacuum heating laminator to obtain a laminate having a layer structure of release sheet / first thermoplastic elastomer layer / glass substrate. The release sheet was then peeled off from this laminate, and a glass substrate was placed on top of the first thermoplastic elastomer layer, which was then bonded again using a vacuum heating laminator to obtain a measurement laminate having a layer structure of glass substrate / first thermoplastic elastomer layer / glass substrate. The total light transmittance and internal haze of this measurement laminate were measured using an NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd., in accordance with JIS K7361-1 and K7136, respectively, and the values ​​for the total light transmittance and internal haze of the first thermoplastic elastomer layer were recorded. In the measurements, the values ​​measured for one glass substrate were used as the blank (total light transmittance 100%, haze 0%).

[0127] <Production Example 1: Production of Thermoplastic Elastomer 1> Using styrene as the aromatic vinyl compound and isoprene as the linear conjugated diene compound, a hydrogenated block copolymer (hydrogenated block copolymer) was produced by the following procedure: The hydrogenated block copolymer produced has a triblock structure in which polymer block (A) is bonded to both ends of polymer block (B).

[0128] A reactor equipped with a stirrer and thoroughly purged with nitrogen was charged with 256 parts of dehydrated cyclohexane, 25.0 parts of dehydrated styrene, and 0.615 parts of n-dibutyl ether, and 1.35 parts of n-butyllithium (15% cyclohexane solution) was added with stirring at 60°C to initiate polymerization. The reaction was continued for 60 minutes with stirring at 60°C. The polymerization conversion at this point was 99.5% (the polymerization conversion was measured by gas chromatography; the same applies hereinafter).

[0129] Next, 50.0 parts of dehydrated isoprene was added, and stirring was continued at the same temperature for 30 minutes, at which point the polymerization conversion was 99%. Thereafter, 25.0 parts of dehydrated styrene was further added and stirred at the same temperature for 60 minutes, at which point the polymerization conversion rate was nearly 100%. Next, 0.5 parts of isopropyl alcohol was added to the reaction solution to terminate the reaction, thereby obtaining a solution (i) containing a block copolymer. The weight average molecular weight (Mw) of the block copolymer in the obtained solution (i) was 44,900, the molecular weight distribution (Mw / Mn) was 1.03, and the ratio of the weight fraction wA of the styrene polymer block to the weight fraction wB of the isoprene polymer block was wA / wB = 50 / 50.

[0130] Next, solution (i) was transferred to a pressure-resistant reactor equipped with a stirrer, and 4.0 parts of a silica-alumina-supported nickel catalyst (E22U, 60% nickel loading; manufactured by JGC Chemical Industries, Ltd.) as a hydrogenation catalyst and 350 parts of dehydrated cyclohexane were added and mixed. The atmosphere inside the reactor was replaced with hydrogen gas, and hydrogen was further supplied while stirring the solution. The hydrogenation reaction was carried out at a temperature of 170°C and a pressure of 4.5 MPa for 6 hours to hydrogenate the block copolymer, yielding solution (iii) containing the hydrogenated block copolymer (ii). The weight-average molecular weight (Mw) of the hydrogenated block copolymer (ii) in solution (iii) was 45,100, and the molecular weight distribution (Mw / Mn) was 1.04.

[0131] After completion of the hydrogenation reaction, solution (iii) was filtered to remove the hydrogenation catalyst. Then, 1.0 part of a xylene solution containing 0.1 part of a phosphorus-based antioxidant, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetrakis-t-butyldibenzo[d,f][1.3.2]dioxaphosphepine (Sumitomo Chemical Co., Ltd., "Sumilizer (registered trademark) GP"; hereinafter referred to as "antioxidant A"), was added and dissolved to the filtered solution (iii), to obtain solution (iv).

[0132] Next, solution (iv) was filtered through a ZetaPlus (registered trademark) filter 30H (manufactured by Cuno, pore size 0.5 μm to 1 μm) and then through another metal fiber filter (pore size 0.4 μm, manufactured by Nichidai) to remove minute solids. The solvent cyclohexane, xylene, and other volatile components were removed from the filtered solution (iv) using a cylindrical concentrating dryer (product name "Contro", manufactured by Hitachi, Ltd.) at a temperature of 260°C and a pressure of 0.001 MPa or less. The solids were then extruded in a molten state into strands through a die directly connected to the concentrating dryer, cooled, and cut with a pelletizer to obtain 85 parts of pellets (v) containing the hydrogenated block copolymer and antioxidant A. The weight-average molecular weight (Mw) of the hydrogenated block copolymer (hydrogenated block copolymer) in the obtained pellets (v) was 45,000, and the molecular weight distribution (Mw / Mn) was 1.08. 1The hydrogenation rate measured by H-NMR was 99.9%. A film-like test piece was prepared from the pellet (v) and the glass transition temperature Tg was measured, which was 130°C. The peak value of tan δ of pellet (v) at temperatures between 40°C and 200°C was 1.4. The storage modulus of pellet (v) at 23°C was 0.3 GPa, and the tensile elongation at 23°C was 550%. Therefore, the obtained hydrogenated block copolymer was a thermoplastic elastomer.

[0133] <Production Example 2: Production of Thermoplastic Elastomer 2> A mixture was obtained by adding 2.0 parts of vinyltrimethoxysilane and 0.2 parts of di-t-butyl peroxide to 100 parts of the pellets (v) produced in Production Example 1. This mixture was kneaded using a twin-screw extruder at a barrel temperature of 210°C and a residence time of 80 to 90 seconds. The kneaded mixture was extruded and cut using a pelletizer to obtain pellets (vi) of the silane-modified hydrogenated block copolymer. The glass transition temperature Tg of the pellet (vi) was measured and found to be 124°C. The peak value of tan δ of pellet (vi) at temperatures from 40° C. to 200° C. was 1.3. The storage modulus of pellet (vi) at 23° C. was 0.25 GPa, and the tensile elongation at 23° C. was 550%. Therefore, the obtained silane-modified hydrogenated block copolymer was a thermoplastic elastomer.

[0134] Example 1 (1-1. Preparation of sealing sheet) 60 parts of thermoplastic elastomer 1 (hydrogenated aromatic vinyl compound-conjugated diene block copolymer) produced in Production Example 1 was dissolved in 100 parts of ethylcyclohexane to produce solution 1. The prepared solution 1 was applied to a polycarbonate film having a thickness of 200 μm using an applicator and dried on a hot plate at 110°C to produce laminate 1 having a layer structure of (50 μm-thick first thermoplastic elastomer layer (thermoplastic elastomer 1 layer)) / release sheet (polycarbonate film). The total light transmittance and internal haze of the first thermoplastic elastomer layer were measured by the above-mentioned methods, and the total light transmittance was 99% and the internal haze was 0.1%.

[0135] Next, 60 parts of thermoplastic elastomer 2 (silane-modified hydrogenated aromatic vinyl compound-conjugated diene block copolymer) produced in Production Example 2 was dissolved in 100 parts of ethylcyclohexane to prepare Solution 2. The prepared Solution 2 was applied to a 38 μm-thick release polyethylene terephthalate (PET) film (HY-S10, manufactured by Higashiyama Film Co., Ltd.) using an applicator to form a layer of Solution 2. The layer of Solution 2 was dried on a hot plate at 110°C to prepare Laminate 2 having a layer structure of (50 μm-thick second thermoplastic elastomer layer (thermoplastic elastomer 2 layer)) / (release PET film).

[0136] Laminate 1 and laminate 2 were stacked so that the first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) and the second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) faced each other, and laminate 1 and laminate 2 were bonded together on a hot plate at 110°C. This resulted in laminate 3 having a layer structure of (release sheet (polycarbonate film)) / (first thermoplastic elastomer layer (thermoplastic elastomer 1 layer)) / (second thermoplastic elastomer layer (thermoplastic elastomer 2 layer)) / (release PET film). A rectangular laminate 4 measuring 90 mm×100 mm was cut out from the laminate 3, and the release PET film was peeled off to obtain a laminate 5 as an encapsulating sheet.

[0137] (1-2. Formation of intermediate laminate) A 100 mm square glass substrate on which a layer of silver nanowires was formed was prepared as an electrode layer. Laminate 5 was placed on top of the silver nanowire layer to obtain laminate 6, an intermediate laminate. The second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) was placed in contact with the silver nanowire layer, and the silver nanowire layer was exposed in 5 mm-wide strips on the outer sides of two opposing sides of laminate 5.

[0138] (1-3. Pressurizing the intermediate laminate) The layer of silver nanowires and the second thermoplastic elastomer layer were bonded together by pressing the laminate 6 using a vacuum heating laminator (manufactured by Mikado Technos Co., Ltd.) The bonding conditions were a heating temperature of 135°C, a pressure of 0.3 MPa, a degree of vacuum of 1 kPa, and a holding time of 5 minutes. The thickness of the pressed intermediate laminate (laminate 6) at the peripheral edges was thinner than that at the center.

[0139] (1-4. Peeling off the release sheet) The release sheet (polycarbonate film) was peeled off from the pressed laminate 6 to obtain a laminate 7 having a layer structure of first thermoplastic elastomer layer / second thermoplastic elastomer layer / electrode layer (silver nanowire layer) / glass substrate.

[0140] The surface of the first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) was visually observed within a 90 mm × 100 mm area, and no dents (point-like depressions) were found. Furthermore, the resistance between the two exposed ribbon-shaped silver nanowire layers was initially 70 Ω, but after the laminate 7 was left in an environment of 60°C and 90% Rh for 1,000 hours, it was 80 Ω.

[0141] <Example 2> A 400 μm thick polyimide film was used as the release sheet instead of a 200 μm thick polycarbonate film. Except for the above, the same procedure as in Example 1 was performed to obtain Laminate 7 having a layer structure of first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) / second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) / electrode layer (silver nanowire layer) / glass substrate. No dents were found when the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1. The change in thickness at the peripheral edge of the pressurized intermediate laminate (laminate 6) was more gradual than in Example 1.

[0142] Example 3 A 500 μm thick polycarbonate film (surface arithmetic mean roughness Ra=2 nm) was used as the release sheet instead of the 200 μm thick polycarbonate film. Except for the above, the same operation as in Example 1 was performed to obtain a laminate 7 having a layer structure of a first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) / a second thermoplastic elastomer layer (a thermoplastic elastomer 2 layer) / an electrode layer (a silver nanowire layer) / a glass substrate. No dents were found when the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1. The change in thickness at the peripheral edge of the pressurized intermediate laminate (laminate 6) was more gradual than in Example 1.

[0143] Example 4 As a release sheet, a 1000 μm thick acrylic resin sheet was used instead of a 200 μm thick polycarbonate film. The acrylic resin sheet was slowly peeled off from the pressurized laminate 6 so as not to crack the glass substrate. Except for the above, the same procedure as in Example 1 was performed to obtain a laminate 7 having a layer structure of a first thermoplastic elastomer layer (thermoplastic elastomer 1 layer), a second thermoplastic elastomer layer (thermoplastic elastomer 2 layer), an electrode layer (silver nanowire layer), and a glass substrate. When the above operation (1-3) was carried out, the acrylic resin sheet was deformed by heat, and the laminate 6 was warped. When the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1, no dents were found.

[0144] <Example 5> A 1000 μm thick polyvinyl chloride sheet was used as the release sheet instead of a 200 μm thick polycarbonate film. Except for the above, the same procedure as in Example 1 was performed to obtain Laminate 7 having a layer structure of first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) / second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) / electrode layer (silver nanowire layer) / glass substrate. When the above-mentioned operation (1-3) was carried out, the laminate 6 did not warp. No dents were found when the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1. The change in thickness at the peripheral edge of the pressurized intermediate laminate (laminate 6) was more gradual than in Example 1.

[0145] <Comparative Example 1> As a release sheet, a 38 μm-thick release PET film (manufactured by Fujimori Kogyo Co., Ltd., treated surface: double-sided differential peeling, arithmetic mean roughness Ra of the surface to be coated with the first thermoplastic elastomer = 15 nm) was used instead of a 200 μm-thick polycarbonate film. Except for the above, the same operation as in Example 1 was performed to obtain a laminate 7 having a layer structure of first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) / second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) / electrode layer (silver nanowire layer) / glass substrate. When the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1, six dents were found, and the surface of the first thermoplastic elastomer layer was partially cloudy.

[0146] <Comparative Example 2> As a release sheet, a 125 μm thick PET film ("A4300", manufactured by Toyobo Co., Ltd.) was used instead of a 200 μm thick polycarbonate film. Except for the above, the same operation as in Example 1 was performed to obtain Laminate 7 having a layer structure of first thermoplastic elastomer layer (thermoplastic elastomer 1 layer) / second thermoplastic elastomer layer (thermoplastic elastomer 2 layer) / electrode layer (silver nanowire layer) / glass substrate.

[0147] When the surface of the first thermoplastic elastomer layer was observed in the same manner as in Example 1, four dents were found, and the surface of the first thermoplastic elastomer layer was partially cloudy.

[0148] <Comparative Example 3> 30 parts of thermoplastic elastomer 1 (hydrogenated aromatic vinyl compound-conjugated diene block copolymer) produced in Production Example 1 and 30 parts of polybutene (manufactured by NOF Corporation, number average molecular weight 1500) as a plasticizer were dissolved in 100 parts of ethylcyclohexane to prepare solution 3. The prepared solution 3 was applied to a 200 μm thick polycarbonate film using an applicator and dried on a hot plate at 110°C to prepare laminate 1 having a layer structure of a 50 μm thick first thermoplastic elastomer layer (thermoplastic elastomer 3 layer) / release sheet (polycarbonate film). Thermoplastic elastomer 3 is a thermoplastic elastomer containing thermoplastic elastomer 1 and polybutene.

[0149] Next, 30 parts of thermoplastic elastomer 2 (silane-modified hydrogenated aromatic vinyl compound-conjugated diene block copolymer) produced in Production Example 2 and 30 parts of polybutene (manufactured by NOF Corporation, number average molecular weight 1500) as a plasticizer were dissolved in 100 parts of ethylcyclohexane to prepare solution 4. The prepared solution 4 was applied to a 38 μm-thick release PET film ("HY-S10", manufactured by Higashiyama Film Co., Ltd.) using an applicator to form a layer of solution 4. The layer of solution 4 was dried on a hot plate at 110°C to prepare laminate 2 having a layer structure of (50 μm-thick second thermoplastic elastomer layer (thermoplastic elastomer 4 layer) / (release PET film). Thermoplastic elastomer 4 is a thermoplastic elastomer containing thermoplastic elastomer 2 and polybutene.

[0150] Except for the above, the same procedures as in Example 1 were performed to obtain a laminate 3 having a layer structure of (release sheet (polycarbonate film)) / (first thermoplastic elastomer layer (thermoplastic elastomer 3 layer)) / (second thermoplastic elastomer layer (thermoplastic elastomer 4 layer)) / (release PET film). A rectangular laminate 4 measuring 90 mm x 100 mm was cut out from laminate 3, and the release PET film was peeled off to obtain laminate 5 as a sealing sheet. A laminate 7 having a layer structure of first thermoplastic elastomer layer (thermoplastic elastomer 3 layer) / second thermoplastic elastomer layer (thermoplastic elastomer 4 layer) / electrode layer (silver nanowire layer) / glass substrate was obtained.

[0151] One dent was found when the surface of the first thermoplastic elastomer layer (layer of thermoplastic elastomer 3) was observed in the same manner as in Example 1. The first thermoplastic elastomer layer was soft and easily scratched, and had strong tack (adhesion).

[0152] <Reference example 1> The resistance value of a 100 mm square glass substrate on which a silver nanowire layer was formed in (1-2) above was measured over a 100 mm area. The initial resistance was 70 Ω, and after being left in an environment of 60°C and 90% Rh for 1000 hours, the resistance value was 110 Ω.

[0153] The results are shown in Tables 1 and 2. In the table, the abbreviations have the following meanings. PC: Polycarbonate film (film containing polycarbonate resin) PI: Polyimide film (film containing polyimide resin) Ac: Acrylic resin film (film containing acrylic resin) PVC: Polyvinyl chloride film (film containing vinyl chloride resin) PET1, Release PET: Release PET film (manufactured by Fujimori Kogyo Co., Ltd., double-sided differential release film) PET2: PET film ("A4300", manufactured by Toyobo Co., Ltd.) E1L: Thermoplastic elastomer 1 layer E2L: Thermoplastic elastomer 2 layer E3L: Thermoplastic elastomer 3 layer E4L: Thermoplastic elastomer 4 layer The storage modulus G' column indicates the storage modulus G' of the thermoplastic elastomer constituting the first thermoplastic elastomer layer. That is, in Comparative Example 3, the storage modulus G' of Thermoplastic Elastomer 3 is shown, and in the other Examples and Comparative Examples, the storage modulus G' of Thermoplastic Elastomer 1 is shown. *1: Not measured.

[0154] [Table 1]

[0155] [Table 2]

[0156] The laminates (sealed products) obtained using the sealing sheets of Examples 1 to 5, in which the release sheet had a thickness of 150 μm or more and the first thermoplastic elastomer layer had a storage modulus G' of 0.1 GPa or more, were free of dents on the surface of the first thermoplastic elastomer layer and had excellent transparency. The intermediate laminates (laminate 6) obtained using the sealing sheets of Examples 2, 3, and 5, in which the release sheets had thicknesses of 300 μm or more, had a gradual change in thickness at the peripheral edge and had a good shape. The intermediate laminates (laminates 6) obtained using the encapsulating sheets of Examples 1, 2, 3, and 5, in which the resin forming the release sheet was any one of polycarbonate resin, polyimide resin, and vinyl chloride resin, were free from warpage and had good shapes.

[0157] On the other hand, in the laminates (sealed products) obtained using the sealing sheets of Comparative Examples 1 and 2, in which the thickness of the release sheet was less than 150 μm, dents were observed on the surface of the first thermoplastic elastomer layer. In addition, the arithmetic mean roughness Ra of the surface of the release sheet was 15 nm, which exceeded 10 nm, and the laminate obtained using the sealing sheet of Comparative Example 1 had partial turbidity on the surface of the first thermoplastic elastomer layer. [Explanation of symbols]

[0158] 100 Encapsulating sheet 110 Release sheet 110U main surface 110D main surface 120 layer (first thermoplastic elastomer layer) 120U main surface 120D main surface 200 Encapsulating Sheet 230 layer (second thermoplastic elastomer layer) 230U main surface

Claims

1. a release sheet having a thickness of 150 μm or more, and a first thermoplastic elastomer layer provided in contact with a first main surface of the release sheet; The encapsulating sheet, wherein the first thermoplastic elastomer layer has a storage modulus at 23°C of 0.1 GPa or more.

2. The encapsulating sheet according to claim 1, wherein the release sheet has a thickness of 300 μm or more.

3. The first thermoplastic elastomer layer an aromatic vinyl compound-conjugated diene block copolymer, and Hydrogenated aromatic vinyl compound-conjugated diene block copolymer The encapsulating sheet according to claim 1 , comprising one or more selected from the group consisting of:

4. The encapsulating sheet according to claim 1 , wherein the release sheet comprises one or more resins selected from the group consisting of vinyl chloride resins, polyimide resins, and polycarbonate resins.

5. The encapsulating sheet according to claim 1, further comprising a second thermoplastic elastomer layer, the release sheet, the first thermoplastic elastomer layer, and the second thermoplastic elastomer layer being arranged in this order in the thickness direction.

6. The second thermoplastic elastomer layer Aromatic vinyl compound-conjugated diene block copolymers modified with silicon atom-containing polar groups, and Hydrogenated aromatic vinyl compound-conjugated diene block copolymer modified with silicon atom-containing polar groups The encapsulating sheet according to claim 5 , comprising one or more selected from the group consisting of:

7. The encapsulating sheet according to claim 1 , wherein the release sheet comprises a substrate layer and a release layer.

8. The encapsulating sheet according to claim 1, wherein the first main surface of the release sheet has an arithmetic mean roughness Ra of 10 nm or less.

9. An encapsulating sheet for a transparent device, comprising the encapsulating sheet according to any one of claims 1 to 8.

10. A step (1) of overlaying the encapsulating sheet according to any one of claims 1 to 8 on an electrode layer to form an intermediate laminate including the release sheet, the first thermoplastic elastomer layer, and the electrode layer in this order; Step (2) of pressing the intermediate laminate; and (3) a step of peeling the release sheet from the pressed intermediate laminate to form an electrode laminate; A method for manufacturing an electrode stack, comprising:

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