Transparent conductive laminated sheet, and electrodes, dimming panels, displays, and touch panels using the same.

Abstract

The present invention provides a transparent conductive laminated sheet, etc., that not only has low surface resistance and excellent conductivity, but also exhibits relatively reduced deterioration of surface resistance during deformation, such as bending or curving during molding processes like in-mold molding, and offers a high degree of installation flexibility. [Solution] A transparent conductive laminate comprising a base sheet and a transparent conductive layer provided on at least one side of the base sheet, wherein the base sheet is a biaxially oriented sheet of polystyrene resin, the biaxially oriented sheet has a glass transition temperature Tg of 85°C or higher, the biaxially oriented sheet has thermal shrinkage stress in the MD direction and TD direction within the range of 0.40 MPa to 1.50 MPa, and the conductive layer contains a conductive polymer, the conductive polymer containing poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), is a transparent conductive laminate sheet.

Description

[Technical Field]

[0001] This invention relates to a transparent conductive laminated sheet, and electrodes, dimming panels, displays, and touch panels using the same. [Background technology]

[0002] Conventionally, transparent conductive laminated sheets have been used as transparent electrodes for various display panels, dimmable panels, transparent touch panels, solar panels, and the like. Known examples of this type of transparent conductive laminated sheet include laminated films in which a transparent conductive film is provided on a transparent substrate film such as polyethylene terephthalate (PET) film or triacetylcellulose (TAC). Known transparent conductive films include those made by depositing indium oxide (In2O3), tin oxide (SnO2), and a mixed sintered body of In2O3 and SnO2 (ITO) onto a transparent substrate film using dry processes such as vacuum deposition or sputtering. More recently, conductive inks containing silver nanowires have been coated onto transparent substrate films using wet processes.

[0003] For example, Patent Document 1 describes a conductive film in which a base film, a transparent conductive coating layer, and a protective layer with a thickness of 3 to 50 nm, consisting of a reaction product of a metal alkoxide, are laminated in this order, the total light transmittance being 60% or more, and the surface resistance of the protective layer side of the conductive film being 10 to 1 × 10 5 A conductive film is disclosed that is characterized by being in the range of Ω / □.

[0004] Furthermore, Patent Document 2 discloses a touchscreen characterized by comprising a first transparent electrode formed on a transparent substrate, a second transparent electrode formed on a transparent film, and a transparent adhesive layer containing a transparent adhesive with conductive balls located between the first and second transparent electrodes. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-313342 [Patent Document 2] Japanese Patent Publication No. 2011-187042 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, there has been a growing demand across various sectors for the installation of panels, including curved windows, skylights, and uneven partitions in hotels, guest rooms, medical facilities, and airports; roof windows and windows in cars, aircraft, and trains; and panels for foldable smartphones, curved smartphones, head-mounted displays, and smart glasses. Along with this, there is an increasing need for greater flexibility in the installation locations of these panels, such as installation on uneven or stepped surfaces with ribs or grid ribs, or installation on curved or bent surfaces, which were previously difficult.

[0007] However, conventional transparent conductive laminated sheets are formed in a flat shape and designed for installation on a flat surface, resulting in poor subsequent molding processability and the inability to install them on uneven surfaces, stepped surfaces, curved surfaces, or bent surfaces. Furthermore, our inventors have newly discovered that in transparent conductive layers using metals such as silver nanowires, the surface resistance of the transparent conductive film increases significantly due to stress applied during bending and deformation. As a result, the transparent conductive film cannot maintain its initial conductivity after installation, and its conductivity deteriorates significantly. For example, when a conventional transparent conductive laminated sheet is in-mold molded into a semicircular shape with a radius of curvature R of 35 mm, the surface resistance increases by more than 1000 times compared to before molding.

[0008] The present invention has been made in view of the above problems. Specifically, the present invention aims to provide a transparent conductive laminated sheet, etc., that not only has low surface resistance and excellent conductivity, but also relatively reduced deterioration of surface resistance during deformation, such as bending or curving during molding processes such as in-mold molding, and offers a high degree of installation flexibility. Another object of the present invention is to provide electrodes, dimming panels, displays, and touch panels, etc., that exhibit low surface resistance and excellent conductivity even when installed on uneven surfaces, curved surfaces, steps, or bends. [Means for solving the problem]

[0009] As a result of diligent research to solve the above problems, the inventors of the present invention have newly developed a transparent conductive laminated sheet comprising a predetermined biaxially oriented sheet and a conductive layer containing a predetermined conductive polymer, and have newly discovered that the deterioration of the surface resistance value during deformation of this transparent conductive laminated sheet is relatively suppressed, thus completing the present invention.

[0010] In other words, the present invention provides various specific embodiments as shown below. (1) A transparent conductive laminate comprising a base sheet and a transparent conductive layer provided on at least one side of the base sheet, wherein the base sheet is a biaxially oriented sheet of polystyrene resin, the biaxially oriented sheet has a glass transition temperature Tg of 85°C or higher, the biaxially oriented sheet has thermal shrinkage stress in the MD direction and TD direction within the range of 0.40 MPa to 1.50 MPa, and the conductive layer contains a conductive polymer, the conductive polymer containing poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), wherein the conductive laminate is a transparent conductive laminate.

[0011] (2) A transparent conductive laminate sheet as described in (1), wherein the total light transmittance (CIE standard light source D65) measured in accordance with JIS K7136 is 70% or more.

[0012] (3) A transparent conductive laminated sheet according to (1) or (2) having a haze value of 15% or less.

[0013] (4) The polystyrene resin contains one or more selected from the group consisting of a styrene homopolymer, a (meth)acrylic acid-styrene copolymer, an acrylonitrile-styrene copolymer (AS), a styrene-butadiene block copolymer (SBC), a (meth)acrylic acid alkyl ester-styrene copolymer (MS), a (meth)acrylic acid acrylate-butadiene-styrene copolymer (MBS), and an acrylonitrile-butadiene-styrene copolymer (ABS), and is the transparent conductive laminated sheet according to any one of (1) to (3).

[0014] (5) The biaxially stretched sheet is the transparent conductive laminated sheet according to any one of (1) to (4), wherein the stretching ratios in the MD direction and the TD direction are each within the range of 1.8 times or more and 3.2 times or less.

[0015] (6) The biaxially stretched sheet is the transparent conductive laminated sheet according to any one of (1) to (5), and has a thickness of 80 μm or more and 150 μm or less. [[ID=**10**]] [[ID=**11**]]

[0016] [[ID=**12**]] [[ID=**13**]](7) The conductive layer has a surface resistance value of 1.0×10[[ID=**14**]] 1 [[ID=**15**]]Ω or more and less than 1.0×10[[ID=**16**]] 4 [[ID=**17**]]Ω, and is the transparent conductive laminated sheet according to any one of (1) to (6). [[ID=**18**]] [[ID=**19**]]

[0017] [[ID=**20**]] [[ID=**21**]](8) The transparent conductive laminated sheet according to any one of (1) to (7), wherein the magnification of the increase in the surface resistance value of the conductive layer is 8.0 times or less before and after the transparent conductive laminated sheet is stretched by 50% at a temperature of 100 °C and a speed of 50 mm / min. [[ID=**22**]] [[ID=**23**]]

[0018] [[ID=**24**]] [[ID=**25**]](9) An electrode comprising the transparent conductive laminated sheet according to any one of (1) to (8). [[ID=**26**]] [[ID=**27**]]

[0019] [[ID=**28**]] [[ID=**29**]](10) A dimming panel comprising the transparent conductive laminated sheet according to any one of (1) to (8). [[ID=**30**]] [[ID=**31**]]

[0020] [[ID=**32**]] [[ID=**33**]](11) A display comprising the transparent conductive laminated sheet according to any one of (1) to (8). [[ID=**34**]]

[0021] (12) A touch panel comprising the transparent conductive laminated sheet according to any one of (1) to (8). [Effect of the Invention]

[0022] According to one aspect of the present invention, not only is the surface resistance value low and the conductivity excellent, but also, for example, during molding processes such as in-mold molding, when bent or curved, the deterioration of the surface resistance value during deformation is relatively reduced, and a transparent conductive laminated sheet or the like with a high degree of installation freedom can be realized. And by using the transparent conductive laminated sheet, even when installed on an uneven surface, a curved surface, a stepped portion, or a bent portion, electrodes, dimming panels, displays, touch panels, etc. that exhibit low surface resistance and excellent conductivity can be realized. [Embodiments for Carrying Out the Invention]

[0023] Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are examples for explaining the present invention, and the present invention is not limited thereto. That is, the present invention can be arbitrarily modified and implemented within the scope not departing from its gist. In this specification, for example, the numerical range notation such as "1 to 100" includes both the lower limit value "1" and the upper limit value "100". The same applies to the notation of other numerical ranges.

[0024] (Transparent Conductive Laminated Sheet) The transparent conductive laminated sheet of this embodiment comprises a base sheet and a transparent conductive layer provided on at least one side of the base sheet. The base sheet is a biaxially oriented sheet of polystyrene resin, the biaxially oriented sheet has a glass transition temperature Tg of 85°C or higher, the biaxially oriented sheet has thermal shrinkage stress in the MD direction and TD direction within the range of 0.40 MPa to 1.50 MPa, and the conductive layer contains a conductive polymer, the conductive polymer containing poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS). The transparent conductive laminated sheet of this embodiment exhibits excellent conductivity even in its sheet form, and even when installed on uneven surfaces, curved surfaces, steps, or bends, deterioration of surface resistance is suppressed, allowing it to maintain relatively high conductivity. For example, it can suppress or prevent electrostatic discharge damage to electronic components.

[0025] <Base sheet> The base sheet is a support member that supports the conductive layer. In this embodiment, a biaxially oriented sheet of polystyrene resin is used as the base sheet. Since the biaxially oriented sheet of polystyrene resin has excellent shape conformability and tensile elongation, using it as the base sheet can improve the shape conformability and tensile elongation when installing the laminated sheet on uneven surfaces, curved surfaces, steps, or bends. Furthermore, since the biaxially oriented sheet of polystyrene resin also has excellent transparency, using it as the base sheet can impart high total light transmittance and low haze to the laminated sheet obtained after molding.

[0026] The polystyrene resin used herein refers to a resin having styrene monomer units. Polystyrene resins may also contain monomer units other than styrene monomer units (hereinafter sometimes simply referred to as "other monomer units"). That is, a polystyrene resin may be a styrene homopolymer containing only styrene monomer units as monomer units, or a styrene copolymer containing styrene monomer units and other monomer units as monomer units. Here, the content of styrene monomer units in the polystyrene resin is preferably 10% by mass or more, and preferably 100% by mass or less, relative to the total of styrene monomer units and other monomer units. The styrene monomer content may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, relative to the total mass of the polystyrene resin, and may be 95% by mass or less, 92% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less. Since polystyrene resin has relatively high transparency and rigidity, using it as a base film for laminated sheets can provide desirable transparency and strength.

[0027] Examples of styrene monomer units include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, ethylstyrene, and pt-butylstyrene. Among these, styrene is preferred.

[0028] Other monomer units that polystyrene resins may contain include, for example, (meth)acrylic monomer units such as (meth)acrylic acid, maleic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate; conjugated diolefin monomer units such as butadiene and isoprene; and unsaturated nitriles such as acrylonitrile and methacrylonitrile. Examples of monomer units include, but are not limited to, amide monomer units such as (meth)acrylamide and n-methylolmethacrylamide; and polyfunctional vinyl monomer units such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, diallyl phthalate, trimethylolpropane triacrylate, glycerin diallyl ether, polyethylene glycol dimethacrylate, and polyethylene glycol diacrylate. These can be used individually or in any combination and ratio of two or more types.

[0029] Specific examples of polystyrene resins include, but are not limited to, styrene homopolymers (also called general-purpose polystyrene (GPPS)), (meth)acrylic acid-styrene copolymers, and acrylonitrile-styrene copolymers (AS). Furthermore, various styrene-butadiene copolymers, such as styrene-butadiene block copolymer (SBC), alkyl (meth)acrylate-styrene copolymer (MS), alkyl (meth)acrylate-butadiene-styrene copolymer (MBS), and acrylonitrile-butadiene-styrene copolymer (ABS), are also examples of polystyrene resins, but are not limited to these. These can be used individually or in any combination and ratio of two or more types.

[0030] The styrene unit content in the (meth)acrylic acid-styrene copolymer can be appropriately set according to the desired performance and is not particularly limited, but may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, and may be 95% by mass or less, 92% by mass or less, or 90% by mass or less, based on the total mass of the (meth)acrylic acid-styrene copolymer. On the other hand, the (meth)acrylic acid unit content in the (meth)acrylic acid-styrene copolymer may be 5% by mass or more, 8% by mass or more, or 10% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total mass of the (meth)acrylic acid-styrene copolymer.

[0031] The styrene unit content in the acrylonitrile-styrene copolymer (AS) can be appropriately set according to the desired performance and is not particularly limited, but may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, and may be 95% by mass or less, 92% by mass or less, or 90% by mass or less, based on the total mass of the acrylonitrile-styrene copolymer. On the other hand, the acrylonitrile unit content in the acrylonitrile-styrene copolymer may be 5% by mass or more, 8% by mass or more, or 10% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total mass of the acrylonitrile-styrene copolymer.

[0032] The styrene unit content in the styrene-butadiene copolymer can be set appropriately according to the desired performance and is not particularly limited, but may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, and may be 95% by mass or less, 92% by mass or less, or 90% by mass or less, based on the total mass of the styrene-butadiene copolymer. On the other hand, the butadiene unit content in the styrene-butadiene copolymer may be 5% by mass or more, 8% by mass or more, or 10% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total mass of the styrene-butadiene copolymer.

[0033] The styrene-butadiene copolymer may consist only of styrene units and butadiene units, or it may further contain other monomer units in addition to the styrene units and butadiene units.

[0034] If the styrene-butadiene copolymer consists only of styrene units and butadiene units, the styrene-butadiene copolymer may be a block copolymer having a block of styrene units and a block of butadiene units. If the styrene-butadiene copolymer further contains other monomer units, the styrene-butadiene copolymer may be a copolymer containing styrene units, butadiene units and alkyl (meth)acrylate units (e.g., methyl (meth)acrylate) (sometimes referred to as "MBS"), or a copolymer containing styrene units, butadiene units and acrylonitrile units (hereinafter also referred to as "ABS"). In one embodiment, the styrene-butadiene copolymer may be at least one selected from the group consisting of SBC, MBS, and ABS.

[0035] Styrene-butadiene block copolymer (SBC) is a block copolymer containing styrene units and butadiene units. An SBC may contain styrene blocks and butadiene blocks, and may also contain styrene-butadiene blocks. For example, an SBC may have a linear molecular structure produced by living anionic polymerization using styrene and butadiene as monomers. Note that high-impact polystyrene (HIPS) is a styrene-butadiene graft copolymer and therefore does not fall under the category of SBC in this embodiment.

[0036] SBC may have a block A consisting of styrene units and a block B consisting of butadiene units. SBC may be an AB isomer formed by the bonding of block A and block B, an ABA isomer formed by the bonding of a first block A, block B and a second block B, or a BAB isomer formed by the bonding of a first block B, block A and a second block B. Furthermore, SBC may further contain a block C formed by the bonding of block A and block B, for example, an ABC isomer formed by the bonding of block A, block B and block C.

[0037] The styrene unit content in SBC can be set appropriately according to the desired performance and is not particularly limited, but may be 70% by mass or more, 75% by mass or more, or 80% by mass or more, and may be 95% by mass or less, 92% by mass or less, or 90% by mass or less, based on the total mass of SBC. The butadiene unit content in SBC may be 5% by mass or more, 8% by mass or more, or 10% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total mass of SBC.

[0038] The styrene unit content in MBS can be set appropriately according to the desired performance and is not particularly limited, but may be 30% by mass or more, 35% by mass or more, or 40% by mass or more, or 60% by mass or less, 55% by mass or less, or 50% by mass or less, based on the total mass of MBS. The butadiene unit content in MBS may be 3% by mass or more, 5% by mass or more, or 7% by mass or more, or 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of MBS. The methyl (meth)acrylate unit content in MBS may be 15% by mass or more, 20% by mass or more, or 25% by mass or more, or 50% by mass or less, 45% by mass or less, or 40% by mass or less, based on the total mass of MBS.

[0039] The styrene unit content in ABS can be set appropriately according to the desired performance and is not particularly limited, but may be 10% by mass or more and 50% by mass or less based on the total mass of ABS. The butadiene unit content in ABS may be 5% by mass or more and 30% by mass or less based on the total mass of ABS. The acrylonitrile unit content in ABS may be 5% by mass or more and 30% by mass or less based on the total mass of ABS.

[0040] Furthermore, each monomer unit constituting the polystyrene resin may be derived from biomass, and the polystyrene resin itself may be derived from biomass. In addition, some or all of the above styrene units may be derived from biomass. For example, some or all of the monomer units contained in the styrene-butadiene copolymer may be recycled monomer units, and the styrene-butadiene copolymer itself may be a recycled block copolymer. For example, some or all of the above styrene units may be derived from biomass.

[0041] Polystyrene resins can be used in combination of two or more types. For example, (1) an alloy of GPPS and SBC, (2) an alloy of GPPS and MS, (3) an alloy of GPPS and MBS, (4) an alloy of GPPS and ABS, (5) an alloy of SBC and MS, (6) an alloy of SBC and MBS, (7) an alloy of SBC and ABS, (8) an alloy of MS and MBS, (9) an alloy of MS and ABS, (10) an alloy of MBS and ABS, (11) an alloy of GPPS, SBC and MS, (12) an alloy of GPPS, SBC and MBS, (13) an alloy of GPPS, SBC and ABS, (14) an alloy of GPPS, MS and MBS, (15) an alloy of GPP (16) an alloy of S, MS, and ABS, (17) an alloy of GPPS, MBS, and ABS, (18) an alloy of SBC, MS, and MBS, (19) an alloy of SBC, MBS, and ABS, (20) an alloy of GPPS, SBC, MS, and MBS, (21) an alloy of GPPS, SBC, MS, and ABS, (22) an alloy of GPPS, SBC, MBS, and ABS, (23) an alloy of GPPS, MS, MBS, and ABS, (24) an alloy of SBC, MS, MBS, and ABS, (25) an alloy of GPPS, SBC, MS, MBS, and ABS.

[0042] The weight-average molecular weight (Mw) of polystyrene-based resins, measured by the SEC method, is not particularly limited and can be set appropriately according to the desired performance. For example, it may be 50,000 or more, 100,000 or more, or 150,000 or more, and may be 450,000 or less, 400,000 or less, or 350,000 or less. The weight-average molecular weight (Mw) can also be measured using gel permeation chromatography (GPC). For example, it can be determined using tetrahydrofuran as the eluent and polystyrene as the standard substance.

[0043] The glass transition temperature (Tg) of the polystyrene resin used here is preferably 85°C or higher. By using a polystyrene resin with a relatively high glass transition temperature (Tg) in this way, process tolerance during molding can be increased, and high heat resistance can be imparted after molding. The glass transition temperature (Tg) of the polystyrene resin is more preferably 87°C or higher, and even more preferably 90°C or higher. The upper limit is not particularly limited, but may be 120°C or lower. In this specification, the glass transition temperature (Tg) refers to the value obtained from a DSC curve measured using a differential scanning calorimetry device (DSC vesta (manufactured by Rigaku Corporation)) in accordance with JIS K7121, under the conditions of a temperature range of 30 to 200°C and a heating rate of 10°C / min.

[0044] The base sheet may further contain other resin components (such as thermosetting resins or thermoplastic resins) in addition to the polystyrene resin described above. For example, the base sheet may further contain high-impact polystyrene resin (HIPS). In this case, the content of the high-impact polystyrene resin may be set appropriately according to the desired performance and is not particularly limited, but from the viewpoint of moldability and thermal stability, it may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, or 5.0% by mass or less, 3.0% by mass or less, or 1.0% by mass or less, based on the total mass of the base sheet. The other resin components can be included, for example, in the resin composition prepared when the base sheet is formed.

[0045] Furthermore, the base sheet may contain, in addition to the polystyrene resin and other resin components mentioned above, additives known in the industry. Examples include, but are not limited to, these additives: mold release agents such as higher fatty acids having 10 to 25 carbon atoms, higher fatty acid amides, higher fatty acid metal salts, polysiloxanes, and fluororesins; gelation inhibitors (e.g., polyoxyethylene alkyl ethers (POE)); colorants such as dyes and pigments; organic fillers; inorganic fillers; reinforcing fibers; antioxidants; heat stabilizers; light stabilizers; ultraviolet absorbers; flame retardants; antistatic agents; surfactants; rust inhibitors; defoamers; fluorescent agents; lubricants; plasticizers; and colorants. Each of these additives can be used individually or in combination of two or more. The content of these additives is not particularly limited and can be set appropriately according to the desired performance, but from the viewpoint of moldability and thermal stability, it may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, based on the total mass of the base sheet, and may be 5.0% by mass or less, 3.0% by mass or less, or 1.0% by mass or less. These additives can be included, for example, in the resin composition prepared when the base sheet is formed.

[0046] The base sheet used in this embodiment is a biaxially oriented polystyrene resin sheet (BOPS) obtained by biaxially stretching the polystyrene resin described above. By using such a biaxially oriented polystyrene resin sheet, the shape-following ability and tensile elongation to uneven surfaces, curved surfaces, steps, and bends during molding are improved, and molding can be performed at relatively high temperatures, thereby increasing the process tolerance during molding. Furthermore, it is possible to realize a transparent conductive laminate sheet with excellent strength and toughness (tensile modulus of elasticity and tensile elongation at break), and relatively high heat resistance can be provided.

[0047] A biaxially oriented sheet can be obtained, for example, by melt-kneading a resin composition containing the polystyrene resin and other optional components mentioned above using an extruder, extruding it into a sheet from a die (e.g., a T-die), then pressurizing and heating the melt-extruded film as needed, and stretching the resulting unstretched sheet sequentially or simultaneously in the biaxial direction. The preparation of the resin composition can be carried out according to conventional methods and is not particularly limited. Each of the above-mentioned components can be manufactured and processed by known methods such as kneading, melt-kneading, granulation, extrusion molding, pressing, or injection molding. When performing melt-kneading, commonly used single-screw or twin-screw extruders and various kneaders can be used. When supplying each component to these melt-kneading devices, each component may be dry-blended beforehand using a mixing device such as a tumbler or Henschel mixer.

[0048] Typically, an unstretched sheet is stretched preferably in the MD direction (Machine Direction; longitudinal direction) to obtain a uniaxially oriented sheet, and then further stretched in the TD direction (Transverse Direction; transverse direction) to obtain a biaxially oriented sheet. The stretching temperature at this time can be set appropriately according to the type and composition of the resin composition used, the desired performance of the biaxially oriented sheet, etc., and is not particularly limited, but for example it may be 90°C or higher or 100°C or higher, or 150°C or lower or 140°C or lower. At this time, simultaneous biaxial stretching can be performed instead of sequential stretching. Furthermore, after the stretching process, it is preferable to perform heat treatment (heat setting) for 1 to 600 seconds at, for example, 100 to 240°C, as needed. During heat setting, methods known in the industry, such as contact heat treatment and non-contact heat treatment, can be used, and the type is not particularly limited. For example, heat setting can be performed using known equipment such as non-contact heaters, ovens, blow devices, heat rolls, cooling rolls, heat presses, and double belt heat presses. At this time, if necessary, a release film or porous film known in the industry can be placed on the surface of the unstretched sheet and subjected to heat and pressure treatment.

[0049] In the stretching process, the stretching ratios in the MD direction and the TD direction when biaxial stretching may be set appropriately according to the desired performance, etc., and are not particularly limited. However, from the viewpoint of strength, toughness (tensile modulus and tensile elongation at break), transparency, etc., they may be 1.8 times or more, 2.0 times or more, or 2.2 times or more, respectively, and may be 3.2 times or less, 3.1 times or less, or 3.0 times or less, relative to the unstretched sheet. The stretching ratios in the MD direction and the TD direction may be the same or different. In addition, the total stretching ratio in the MD direction * TD direction (stretching ratio expressed as m × n, where the stretching ratio in the MD direction is m and the stretching ratio in the TD direction is n) may be 3.5 times or more, or 4.0 times or more, and may be 10.0 times or less, or 8.0 times or less.

[0050] The thickness of the biaxially oriented sheet may be set appropriately according to the desired performance, etc., and is not particularly limited, but may be 80 μm or more, 85 μm or more, 90 μm or more, or 95 μm or more from the viewpoint of strength, toughness (tensile modulus and tensile elongation at break), transparency, etc., and may be 150 μm or less, 140 μm or less, 130 μm or less, or 120 μm or less from the viewpoint of excellent transparency. In this specification, the thickness of the unoriented sheet, the biaxially oriented sheet, and the laminated sheet described later each refer to the average value of five randomly selected locations.

[0051] The glass transition temperature (Tg) of the biaxially oriented sheet is preferably 85°C or higher. By using a biaxially oriented sheet with a relatively high glass transition temperature (Tg), the process tolerance during molding can be increased, and high heat resistance can be imparted after molding. The glass transition temperature (Tg) of the biaxially oriented sheet is more preferably 87°C or higher, and even more preferably 90°C or higher. The upper limit is not particularly limited, but may be 120°C or lower. In this specification, the glass transition temperature (Tg) refers to the value obtained from a DSC curve measured using a differential scanning calorimetry device (DSC vesta (manufactured by Rigaku Corporation)) in accordance with JIS K7121, under the conditions of a temperature range of 30 to 200°C and a heating rate of 10°C / min.

[0052] The total light transmittance of the biaxially oriented sheet can be set appropriately according to the desired performance, etc., and is not particularly limited, but is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the total light transmittance is preferably 99% or less, more preferably 95% or less, and even more preferably 93% or less. In this specification, the total light transmittance of the biaxially oriented sheet is the value measured in accordance with JIS K7136 under the CIE standard light source D65. Detailed measurement conditions shall be the same as those described in the examples.

[0053] The haze of a biaxially oriented sheet may be set appropriately according to the desired performance, etc., and is not particularly limited. When transparency is required, the haze of the biaxially oriented sheet may be 15% or less, 12% or less, 10% or less, 8% or less, or 5% or less, and may be 0.1% or more. In this specification, the haze of the biaxially oriented sheet is a value measured in accordance with JIS K7136. Detailed measurement conditions shall be the same as those described in the examples.

[0054] The thermal shrinkage stress of the biaxially oriented sheet can be set appropriately according to the desired performance, etc., and is not particularly limited, but from the viewpoint of formability, toughness (tensile modulus and tensile elongation at break), heat resistance, etc., it is preferable that the thermal shrinkage stress in the MD direction and TD direction are within the range of 0.40 MPa to 1.50 MPa, respectively. The lower limit of the thermal shrinkage stress may be 0.42 MPa or more, 0.44 MPa or more, or 0.46 MPa or more. The upper limit of the thermal shrinkage stress may be 1.30 MPa or less, 1.20 MPa or less, 1.10 MPa or less, or 1.00 MPa or less. The thermal shrinkage stress in the MD direction and the thermal shrinkage stress in the TD direction may be the same or different. In this specification, the thermal shrinkage stress of the biaxially oriented sheet is the value measured by the method described in the examples.

[0055] <Conductive layer> A conductive layer is provided on at least one side of the base sheet described above. Here, in this specification, "provided on at least one side of the base sheet" means that the conductive layer is provided on only one surface of the base sheet, on only the other surface (back surface) of the base sheet, and on both surfaces (front and back surfaces) of the base sheet. Furthermore, it means that not only the conductive layer is directly placed on the base sheet, but also the conductive layer is provided on a configuration in which any layer (e.g., a primer layer, an adhesive layer, etc.) is interposed between the base sheet and the conductive layer, causing the base sheet and the conductive layer to be spaced apart.

[0056] The conductive layer is a layer that imparts conductivity. In this embodiment, a layer containing a conductive polymer is used as the conductive layer. Since the conductive layer containing a conductive polymer has excellent shape conformability and tensile elongation, using it as a conductive layer can improve shape conformability and tensile elongation to uneven surfaces, curved surfaces, steps, and bends during molding. Furthermore, it is possible to realize a transparent conductive laminate sheet that exhibits excellent conductivity with low surface resistance even when installed on uneven surfaces, curved surfaces, steps, or bends.

[0057] The conductive polymer used here is preferably poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS). Poly(3,4-ethylenedioxythiophene) (PEDOT) is a polythiophene-based conductive polymer whose main chain is composed of a π-conjugated system, and is preferred from the viewpoint of conductivity, transparency, heat resistance, etc. Polystyrene sulfonic acid (PSS) is a so-called polyanion and a polymer electrolyte, and it coordinates to PEDOT and functions as a dopant to form a conductive complex and improve conductivity. In one embodiment, PEDOT / PSS can also be used as a water-dispersible polythiophene derivative as a conductive polymer solution obtained by mixing or polymerizing 3,4-ethylenedioxythiophene (EDOT), which is a conductive polymer monomer, and polystyrene sulfonic acid (PSS), which is a polymer electrolyte and a water-soluble polymer. By using PEDOT / PSS as the conductive polymer, shape conformability and tensile elongation are enhanced. As described above, shape conformability and tensile elongation can be improved when molding uneven surfaces, curved surfaces, stepped sections, or bent sections. Furthermore, deterioration of surface resistance can be suppressed even when installed on uneven surfaces, curved surfaces, stepped sections, or bent sections. In addition, it has excellent conductivity, transparency, and heat resistance, and is also water-dispersible, resulting in excellent film-forming properties when forming a conductive layer.

[0058] The conductive layer may contain other conductive polymers or polyanions other than the PEDOT / PSS described above. Other conductive polymers that can be used in combination include, but are not limited to, polypyrroles, polyacetylenes, polyphenylenes, polyphenylenevinylenes, polyanilines, polyacenes, polythiophenevinylenes, and copolymers thereof. These can be used individually or in any combination and ratio of two or more. Other polyanions that can be used in combination include, but are not limited to, polymers having sulfonic acid groups such as polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacrylate sulfonic acid, poly(2-acrylamide-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polysulfoethyl methacrylate, poly(4-sulfobutyl methacrylate), and polymethacrylateoxybenzene sulfonic acid, as well as polymers having carboxylic acid groups such as polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacrylate carboxylic acid, poly(2-acrylamide-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, and polyacrylic acid. These can be used individually or in any combination and ratio of two or more.

[0059] The conductive polymer PEDOT / PSS mentioned above is well known in the industry and can be appropriately prepared according to conventional methods. In addition, various commercially available products are on the market, such as Clevios® and PH1000 from Heraeus, Baytron® from HC Starck, SELFTRON® from Tosoh Corporation, Sepulzida® from Shin-Etsu Polymer Co., Ltd., and Orgacon S-300 from Agfa Materials Japan Ltd., and any commercially available product can be used as PEDOT / PSS in this embodiment.

[0060] When preparing water-dispersible polythiophene derivatives, water is usually used as the dispersion medium. In this case, the conductivity tends to improve when a water-soluble solvent is used in combination as the dispersion medium. Examples of such water-soluble solvents include: alcohols such as methanol, ethanol, and isopropanol; polar solvents such as N-methyl-2-pyrrolidone, N-methylacetamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylene phosphortriamide, N-vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide; phenols such as cresol, phenol, and xylenol; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, glycerin, diglycerin, D-glucose, D-glucitol, and isoprene. Examples of polyhydric aliphatic alcohols include glycols, butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and neopentyl glycol; carbonate compounds such as ethylene carbonate and propylene carbonate; ether compounds such as dioxane and diethyl ether; linear ethers such as dialkyl ethers, propylene glycol dialkyl ethers, polyethylene glycol dialkyl ethers, and polypropylene glycol dialkyl ethers; heterocyclic compounds such as 3-methyl-2-oxazolidinone; and nitrile compounds such as acetonitrile, glutalodinitrile, methoxyacetonitrile, propionitrile, and benzonitrile. However, the list is not particularly limited to these. These can be used individually or in any combination and ratio of two or more. Among these, alcohols such as methanol, ethanol, and isopropanol, and polyhydric aliphatic alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol are preferred.The content of the water-soluble solvent can be set appropriately according to the desired performance and is not particularly limited, but may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more, based on the water-dispersible polythiophene derivative as a conductive polymer solution, or 5.0% by mass or less, 3.0% by mass or less, or 1.0% by mass or less. These water-soluble solvents can be included, for example, when preparing the conductive polymer solution.

[0061] Furthermore, when preparing water-dispersible polythiophene derivatives, pH adjusters may be added to adjust the pH and mitigate acidity. Examples of such pH adjusters include, but are not limited to, sodium hydroxide, aliphatic amines such as ethanolamine, imidazoles such as imidazole, pyridines, and metal alkoxides. These can be used individually or in any combination and ratio of two or more. The content of the pH adjuster may be set appropriately according to the desired performance and is not particularly limited, but may be 0.01% by mass or more, 0.03% by mass or more, or 0.05% by mass or more, based on the water-dispersible polythiophene derivative as a conductive polymer solution, and may be 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less. These water-soluble solvents can be included, for example, when preparing the conductive polymer solution.

[0062] Furthermore, the preparation of the water-dispersible polythiophene derivative may include, but is not limited to, any known additives in the industry. Examples include, but are not limited to, colorants such as dyes and pigments; organic fillers; inorganic fillers; reinforcing fibers; antioxidants; ultraviolet absorbers; surfactants; and defoamers. Each of these additives can be used individually or in combination of two or more. The content of these additives can be set appropriately according to the desired performance and is not particularly limited, but may be 0.01% by mass or more, 0.03% by mass or more, or 0.05% by mass or more, based on the water-dispersible polythiophene derivative as a conductive polymer solution, and may be 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less. These additives can be included, for example, when preparing the conductive polymer solution.

[0063] The method for forming the conductive layer can be carried out according to conventional methods and is not particularly limited. Typically, a conductive polymer dispersion is applied to the aforementioned substrate sheet by coating methods such as gravure coaters, roll coaters, curtain flow coaters, spin coaters, bar coaters, reverse coaters, kiss coaters, fountain coaters, rod coaters, air doctor coaters, knife coaters, blade coaters, cast coaters, and screen coaters; spraying methods such as air spraying, airless spraying, and rotor dampening; and immersion methods such as dipping. If necessary, a drying treatment is performed at a drying temperature of, for example, 40 to 80°C to obtain the conductive layer.

[0064] Furthermore, when forming a conductive layer on a substrate sheet, surface treatment of the substrate sheet surface may be performed in accordance with conventional methods to improve adhesion and other aspects. Such surface treatments can be those known in the industry and are not particularly limited, but examples include corona discharge treatment, plasma treatment, and flame treatment.

[0065] The thickness of the conductive layer may be appropriately set according to desired performance and the like, and is not particularly limited. However, from the viewpoints of conductivity, strength, toughness (tensile elastic modulus and tensile elongation at break), transparency, etc., it may be 100 nm or more, 150 nm or more, 200 nm or more, and from the viewpoint of excellent transparency, it may be 700 nm or less, 600 nm or less, 500 nm, or 400 nm or less. In this specification, the thickness of the conductive layer means the average value of five randomly extracted locations.

[0066] From the viewpoint of enhancing the conductivity of the transparent conductive laminated sheet, the surface resistance value of the conductive layer is 1.0×10 1 Ω or more and less than 1.0×10 4 Ω. In one aspect, the surface resistance value of the conductive layer may be 3.0×10 1 Ω or more, or 5.0×10 1 Ω or more, and may also be less than 1.0×10[[ID=1】 3 Ω, less than 5.0×10 2 Ω, or less than 3.0×10 2 Ω. In this specification, the surface resistance value means a value measured by the four-probe method using probes with a 5.0 mm interval in accordance with JIS K7194. The detailed measurement conditions shall conform to the method described in the examples.

[0067] <Laminated Sheet> Since the transparent conductive laminated sheet of this embodiment employs a base material sheet excellent in formability, heat resistance, and toughness and a conductive layer excellent in the above-described shape followability and tensile elongation, as described above, not only is it excellent in conductivity in the form of a sheet, but also when installed on an uneven surface, a curved surface, a stepped portion, or a bent portion, the deterioration of the conductivity (deterioration of the surface resistance value) of the transparent conductive laminated sheet due to its deformation is suppressed.

[0068] More specifically, it is preferable that the increase in the surface resistance of the conductive layer is 8.0 times or less before and after stretching the conductive laminated sheet by 50% at a temperature of 100°C and a speed of 50 mm / min. In one embodiment, the increase in the surface resistance of the conductive layer may be 7.5 times or less, 7.0 times or less, 6.5 times or less, or 6.0 times or less. The lower limit of the increase in the surface resistance of the conductive layer is not particularly limited, but may be 1.0 times or more. In this specification, the upper limit of the surface resistance is measured by the method described in the examples.

[0069] The total light transmittance of the transparent conductive laminate sheet may be set appropriately according to the desired performance, etc., and is not particularly limited. When transparency is required, the total light transmittance of the transparent conductive laminate sheet may be 70% or more, 75% or more, 80% or more, or 85% or more, and may be 99% or less, more preferably 95% or less, and even more preferably 90% or less. In this specification, the total light transmittance of the transparent conductive laminate sheet is the value measured in accordance with JIS K7136 under the CIE standard light source D65. Detailed measurement conditions shall be the same as those described in the examples.

[0070] The haze of the transparent conductive laminate sheet may be set appropriately according to the desired performance, etc., and is not particularly limited. When transparency is required, the haze of the transparent conductive laminate sheet may be 15% or less, 12% or less, 10% or less, 8% or less, or 5% or less, and may be 0.1% or more. In this specification, the haze of the biaxially oriented sheet is the value measured in accordance with JIS K7136. Detailed measurement conditions shall be the same as those described in the examples.

[0071] (Electrodes, dimming panels, displays, touch panels, etc.) The transparent conductive laminated sheet described above can be used, for example, to manufacture transparent electrodes for various display panels, dimmable panels, transparent touch panels, solar panels, and the like. The transparent conductive laminated sheet of this embodiment has excellent moldability, toughness, heat resistance, shape conformability, and tensile elongation, so it can be deformed into a shape that conforms to uneven surfaces, curved surfaces, steps, or bends by applying known molding techniques such as vacuum forming, pressure forming, press forming, and in-mold forming, and can exhibit excellent conductivity even after such deformation. These molding techniques may be known methods (for example, the methods described in "Plastic Processing Technology Handbook" edited by the Society of Polymer Science, Japan, Nikkan Kogyo Shimbun (1995)) and are not particularly limited. [Examples]

[0072] The features of the present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited in any way by these. That is, the materials, amounts used, proportions, processing content, processing procedures, etc., shown in the following examples can be changed as appropriate, as long as they do not depart from the spirit of the present invention. Furthermore, the various manufacturing conditions and evaluation result values ​​in the following examples have meaning as preferred upper or lower limits in embodiments of the present invention, and the preferred numerical range may be defined by a combination of the above upper or lower limits and the values ​​of the following examples or the values ​​of the examples themselves.

[0073] (Preparation Example 1) Production of BOPS-1, a biaxially oriented sheet of polystyrene resin Using pellets of styrene homopolymer (GPPS, manufactured by Toyo Styrene Co., Ltd., model number: HRM63, weight-average molecular weight (Mw): 260,000), an unstretched sheet of Preparation Example 1, with a thickness of 0.5 mm and a width of 170 mm x 170 mm, was prepared using a hot press machine (manufactured by Tester Industries Co., Ltd., SA-303). Subsequently, the obtained unstretched sheet was preheated using a batch-type biaxial stretcher (SDR-507D, manufactured by EVER Sokki Co., Ltd.), and biaxially stretched at a stretching temperature of 125°C with stretching ratios of 2.6 times in the MD direction and 2.6 times in the TD direction to obtain a biaxially oriented sheet of Preparation Example 1 having a thickness of 0.10 mm (biaxially oriented polystyrene resin sheet BOPS-1).

[0074] (Preparation Example 2) Production of BOPS-2, a biaxially oriented polystyrene resin sheet Except for changing the stretching temperature during biaxial stretching to 120°C, a biaxially oriented sheet of Preparation Example 2 with a thickness of 0.10 mm was obtained in the same manner as Preparation Example 1 (Biaxially oriented polystyrene resin sheet BOPS-1).

[0075] (Preparation Example 3) Production of BOPS-3, a biaxially oriented polystyrene resin sheet Except for using an alkyl ester (meth)acrylate-styrene copolymer (MS, manufactured by Toyo Styrene Co., Ltd., Toyo MS, model number: MS-750) instead of GPPS, and changing the stretching temperature during biaxial stretching to 135°C, a biaxially oriented sheet of Preparation Example 3 with a thickness of 0.10 mm was obtained in the same manner as Preparation Example 1 (Biaxially oriented polystyrene resin sheet BOPS-3).

[0076] (Comparative preparation example 1) Production of BOPS-4, a biaxially oriented sheet of polystyrene resin. Except for changing the stretching temperature during biaxial stretching to 135°C, a biaxially oriented sheet of comparative preparation example 1 with a thickness of 0.10 mm was obtained in the same manner as in preparation example 1 (biaxially oriented polystyrene resin sheet BOPS-4).

[0077] (Examples 1-3) The biaxially oriented sheets BOPS-1, 2, and 3 from Preparation Examples 1 to 3 were cut into A4 size sheets measuring 210 mm in width and 297 mm in length to prepare the base sheets for Examples 1 to 3. Subsequently, the surface of each base sheet was corona-treated, and a conductive polymer solution containing poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), prepared according to the transparent conductive coating layer described in Japanese Patent Application Publication No. 2005-313342, was applied to the surface of each base sheet after corona treatment using a bar coater (SA-203, manufactured by Tester Industries Co., Ltd.). The solution was then dried in an oven at 70°C for 5 minutes to produce a conductive layer with a thickness of 350 nm, thereby obtaining the transparent conductive laminated sheets for Examples 1 to 3.

[0078] (Comparative Example 1) A transparent conductive laminated sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that the biaxially oriented sheet BOPS-4 of Comparative Preparation Example 1 was used instead of the biaxially oriented sheet BOPS-1 of Preparation Example 1.

[0079] (Comparative Example 2) For comparative verification, a commercially available electrostatic discharge film (Dai Nippon Package Co., Ltd., Daiclea® Daiclea DC-150), which has an organic conductive film PEDOT / PSS on a stretched PET film (Tg: 75℃), was used as the transparent conductive laminate sheet for Comparative Example 2.

[0080] (Comparative Example 3) A transparent conductive laminate sheet of Comparative Example 3 was obtained in the same manner as in Example 1, except that a conductive ink (silver nanowire aqueous conductive ink, manufactured by NanoCintech, product name: Condective Ink, WCI-TSD) was used to create a conductive layer with a thickness of 350 μm instead of a conductive polymer solution containing PEDOT / PSS.

[0081] (Comparative Example 4) A transparent conductive laminated sheet of Comparative Example 4 was obtained in the same manner as in Example 1, except that the preparation of the conductive layer was omitted.

[0082] The base sheet and transparent conductive laminate sheet obtained as described above were evaluated for their performance as follows.

[0083] <Glass transition temperature Tg> In accordance with JIS K7121, the DSC curves of samples taken from biaxially stretched sheets were measured using a differential scanning calorimetry system (DSC vesta (manufactured by Rigaku Corporation)) in the temperature range of 30 to 200°C under a heating rate of 10°C / min, and the glass transition temperature (Tg) was determined.

[0084] <Thermal shrinkage stress> <Thermal contraction stress> Samples for measurement were prepared by cutting the base sheet into strips measuring 20 mm wide x 150 mm long. The samples were held at both ends with chucks and heated in a 130°C oil bath. The load (in N) applied to the chucks as the molecular orientation was relaxed by thermal motion and the sheet underwent thermal shrinkage was measured using a thermal shrinkage stress measuring device (Tester Industries Co., Ltd., TP-501). The maximum load was measured across the sample cross-sectional area (in mm²). 2 The thermal shrinkage stress (unit: MPa) was calculated by dividing by ). Note that the thermal shrinkage stress is an indicator of the degree of molecular orientation of the biaxially oriented sheet.

[0085] <HAZE> The haze (%) of each laminated sheet was measured using a haze meter NDH5000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136:2000. A smaller haze value indicates higher transparency. Note that haze represents the degree of cloudiness, including both the surface and the interior of the sheet.

[0086] <Total light transmittance> The total light transmittance (%) of each laminated sheet was measured under the CIE standard light source D65, in accordance with JIS K7136:2000, using a haze meter NDH5000 (manufactured by Nippon Denshoku Industries Co., Ltd.). A higher total light transmittance indicates higher transparency. Here, a total light transmittance of 70% or more was marked with ○ (Good), and a total light transmittance of less than 70% was marked with × (Bad).

[0087] <Moldability> Using a vacuum pressure molding machine (FVS-500, manufactured by Wakisaka Engineering Co., Ltd.), each laminated sheet was molded into a semicircular shape using a semicircular mold with a radius of curvature R=35mm. The radius of curvature Rm of the molded product after molding was measured and graded as follows: ○ (Good) if Rm = 35mm or more and 38mm or less, △ (not Good) if Rm = 39mm or more and 50mm or less, and × (Bad) if Rm = more than 51mm or if molding was not possible due to cracking or tearing.

[0088] <Surface resistance value> Using a NSK Analytec MCP-T700, which conforms to JIS K7194 and is equipped with ESP probes spaced 5.0 mm apart, the surface resistance of the conductive layer surface of the laminated sheet was measured using the four-probe method.

[0089] <Surface resistance value after molding> The laminated sheet was cut into 30mm x 100mm sections and subjected to uniaxial stretching (stretching ratio: 1.5x (50% stretch), temperature: 100°C, preheating time: 3 minutes, tensile speed: 50mm / min) using a tensile testing machine (Shimadzu Corporation, Autograph AGS-X) to obtain a uniaxially stretched laminated sheet. This uniaxially stretched laminated sheet was used as a sample for a deformation (stretching) model test in in-mold molding, and the surface resistance of the conductive layer surface was measured in the same manner as described above.

[0090] <Increase in surface resistance> The surface resistance ratio was calculated by dividing the surface resistance value after uniaxial stretching by the surface resistance value of the laminated sheet (before uniaxial stretching).

[0091] [Table 1] [Industrial applicability]

[0092] The transparent conductive laminated sheet of the present invention exhibits excellent conductivity even in its sheet form, and maintains relatively high conductivity even when installed on uneven surfaces, curved surfaces, steps, or bends, as it suppresses deterioration of surface resistance. Therefore, it can be widely and effectively used in various applications where conductivity is required, and is particularly effective as a transparent electrode for various display panels, dimming panels, transparent touch panels, solar panels, etc.

Claims

1. The device comprises a base sheet and a transparent conductive layer provided on at least one side of the base sheet. The aforementioned base sheet has a biaxially oriented sheet of polystyrene resin, The biaxially stretched sheet has a glass transition temperature Tg of 85°C or higher. The biaxially stretched sheet has thermal shrinkage stresses in the MD direction and TD direction that are within the range of 0.40 MPa to 1.50 MPa, respectively. The conductive layer contains a conductive polymer, The conductive polymer contains poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS), Transparent conductive laminated sheet.

2. The total light transmittance (CIE standard light source D65), measured in accordance with JIS K7136, is 70% or higher. The transparent conductive laminated sheet according to claim 1.

3. Haze values ​​of 15% or less The transparent conductive laminated sheet according to claim 1.

4. The polystyrene resin comprises one or more selected from the group consisting of styrene homopolymer, (meth)acrylic acid-styrene copolymer, acrylonitrile-styrene copolymer (AS), styrene-butadiene block copolymer (SBC), (meth)acrylate-styrene copolymer (MS), (meth)acrylic acid-butadiene-styrene copolymer (MBS), and acrylonitrile-butadiene-styrene copolymer (ABS). The transparent conductive laminated sheet according to claim 1.

5. The biaxially stretched sheet has stretch ratios in the MD direction and the TD direction that are within the range of 1.8 times to 3.2 times, respectively. The transparent conductive laminated sheet according to claim 1.

6. The biaxially oriented sheet has a thickness of 80 μm or more and 150 μm or less. The transparent conductive laminated sheet according to claim 1.

7. The conductive layer is 1.0 × 10 1 Ω or more 1.0×10 4 It has a surface resistance value of less than Ω. The transparent conductive laminated sheet according to claim 1.

8. The increase in the surface resistance of the conductive layer is 8.0 times or less before and after stretching the transparent conductive laminate sheet by 50% at a temperature of 100°C and a speed of 50 mm / min. The transparent conductive laminated sheet according to claim 1.

9. A transparent conductive laminated sheet according to any one of claims 1 to 8, electrode.

10. A transparent conductive laminated sheet according to any one of claims 1 to 8, Dimming panel.

11. A transparent conductive laminated sheet according to any one of claims 1 to 8, display.

12. A transparent conductive laminated sheet according to any one of claims 1 to 8, Touch panel.

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