Method for manufacturing an antistatic layer and method for manufacturing an optical laminate.

Abstract

This invention provides a method for manufacturing an antistatic layer suitable for application to image display devices used in harsh environments such as those found in automobiles. [Solution] The provided manufacturing method is a method for manufacturing an antistatic layer for use in an optical laminate, comprising: applying a coating liquid containing a conductive material, a binder resin, and a solvent to the surface of a substrate to form a coating film; and drying the coating film to satisfy the following conditions (1) and (2) to remove the solvent and form the antistatic layer. The conductive material is a single-walled carbon nanotube with a length of 3 μm or more and less than 300 μm. Condition (1): The drying temperature T of the coated film is 50°C or higher. Condition (2): The time Z from the start of applying the coating liquid to the surface of the substrate to the start of drying of the coating film is 0.01 seconds or more and 50 seconds or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an antistatic layer used in an optical laminate, and a method for manufacturing an optical laminate including the antistatic layer.

Background Art

[0002] Image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices, inorganic EL display devices) have become widespread. These image display devices have, for example, a laminated structure including an image display cell such as a liquid crystal cell, an EL light emitting element, and an optical laminate including an optical film such as a polarizing film. The optical laminate may include an adhesive sheet. The adhesive sheet can be used, for example, for joining films included in the optical laminate or for joining an image display cell and the optical laminate.

[0003] Static electricity may be generated during the manufacture or use of an image display device. During manufacture, static electricity is likely to be generated when the optical laminate is bonded to the image display cell. During use, static electricity is likely to be generated when a user touches the image display device. When the image display device is charged by static electricity, problems such as display defects may occur. Patent Document 1 discloses an optical laminate including a polarizing film and a conductive layer containing a conductive polymer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the inventors' research, the optical laminate described in Patent Document 1 has room for further improvement depending on the environment in which the image display device is used. The present invention aims to provide a method for manufacturing an antistatic layer suitable for application to image display devices used in harsh environments such as in automobiles. [Means for solving the problem]

[0006] [1] The manufacturing method according to an embodiment of the present invention (first manufacturing method) is: A method for manufacturing an antistatic layer used in an optical laminate, A coating solution containing a conductive material, a binder resin, and a solvent is applied to the surface of a substrate to form a coating film. The process includes drying the coating film under the following conditions (1) and (2) to remove the solvent and form the antistatic layer, The conductive material is a single-walled carbon nanotube with a length of 3 μm or more and less than 300 μm. Condition (1): The drying temperature T of the coated film is 50°C or higher. Condition (2): The time Z from the start of applying the coating liquid to the surface of the substrate to the start of drying of the coating film is 0.01 seconds or more and 50 seconds or less. [2] In the manufacturing method described in [1] above, the coating film may be dried in a manner that satisfies the following condition (3) in addition to the conditions (1) and (2). Condition (3): The drying time H of the coating film is 10 seconds or more and 150 seconds or less. [3] In the manufacturing method described in [1] or [2] above, the drying temperature T may be 130°C or less. [4] In the manufacturing method described in any of [1] to [3] above, the coating liquid may substantially contain no leveling agent, or it may contain a leveling agent in an amount of 8 parts by weight or less, based on 100 parts by weight of solids contained in the coating liquid. [5] In the manufacturing method described in any of [1] to [4] above, the coating liquid may substantially contain no leveling agent, or it may contain a leveling agent in an amount of 8 parts by weight or less, based on 100 parts by weight of solids contained in the coating liquid, and the coated film may be dried so as to satisfy the condition that the time Z is 15 seconds or less. [6] In the manufacturing method described in any of [1] to [5] above, the coating film having a thickness of 1 μm or more and 12 μm or less may be formed on the surface of the substrate. [7] In the manufacturing method described in any of [1] to [6] above, the substrate may be an optical film. [8] In the manufacturing method described in any of [1] to [7] above, the substrate may include a polarizing film. [9] In the manufacturing method described in any of [1] to [8] above, the formation of the coating film and the drying of the formed coating film may be carried out while transporting the strip-shaped substrate.

[10] In the manufacturing method described in any of [1] to [9] above, the antistatic layer having a thickness of 5 nm to 200 nm may be formed.

[11] In the manufacturing method described in any of [1] to

[10] above, 1.0 × 10 9 The antistatic layer having a surface resistivity of Ω / □ or less may be formed.

[12] In the manufacturing method described in any of [1] to

[11] above, the antistatic layer satisfying the following formula (I) may be formed. However, A and B in formula (I) are the surface resistivity (unit: Ω / □) of the antistatic layer before and after a weathering test (test condition: Z-IN1) as defined in German Industrial Standard DIN75220. -2 ≤ logB - logA ≤ 2 (I)

[13] A manufacturing method according to an embodiment of the present invention (second manufacturing method) is: A method for manufacturing an optical laminate comprising an optical film and an antistatic layer in this order, This includes forming the antistatic layer by the manufacturing method described in any of the above [1] to

[12] .

[14] In the manufacturing method described in

[13] above, the substrate may be an optical film, and the antistatic layer may be formed on the optical film.

[15] In the manufacturing method described in

[13] or

[14] above, the optical film may include a polarizing film.

[16] The manufacturing method according to an embodiment of the present invention (third manufacturing method) is: A method for manufacturing an optical laminate comprising an optical film, an antistatic layer, and an adhesive sheet in this order, This includes forming the antistatic layer by the manufacturing method described in any of the above [1] to

[12] .

[17] In the manufacturing method described in

[16] above, the substrate may be an optical film, and the antistatic layer may be formed on the optical film.

[18] In the manufacturing method described in

[16] or

[17] above, the optical film may include a polarizing film. [Effects of the Invention]

[0007] The present invention provides a method for manufacturing an antistatic layer suitable for application to image display devices used in harsh environments such as those found in automobiles. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of an optical laminate that can be manufactured by the optical laminate manufacturing method according to this embodiment. [Figure 2] This is a schematic cross-sectional view showing an example of an optical laminate that can be manufactured by the optical laminate manufacturing method according to this embodiment. [Figure 3] This is a schematic cross-sectional view showing an example of an optical laminate that can be manufactured by the optical laminate manufacturing method according to this embodiment. [Modes for carrying out the invention]

[0009] The present invention will be described in detail below. However, the present invention is not limited to the embodiments shown below. The present invention can be modified and implemented as necessary without departing from the spirit of the invention.

[0010] [Regarding terminology] In this specification, where the term "weight" appears, it may be interpreted as "mass," the SI unit commonly used to indicate weight. The reverse is also true.

[0011] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic," the expression "(meth)acrylate" means "acrylate and / or methacrylate," the expression "(meth)allyl" means "allyl and / or methallyl," and the expression "(meth)acrolein" means "acrolein and / or metacrolein."

[0012] ≪≪1. Method for Manufacturing an Antistatic Layer≫≫ The method for manufacturing an antistatic layer according to this embodiment (hereinafter also referred to as the "first manufacturing method") is a method for manufacturing an antistatic layer used in an optical laminate. In the first manufacturing method, a coating liquid containing a conductive material, a binder resin, and a solvent is applied to the surface of a substrate to form a coating film. The formed coating film is dried to satisfy the following conditions (1) and (2). Drying removes the solvent and forms an antistatic layer. The formed antistatic layer usually constitutes a laminate with the substrate until it is peeled off from the substrate. The conductive material used in the first manufacturing method is a single-walled carbon nanotube (CNT) with a length of 3 μm or more and less than 300 μm. The formed antistatic layer contains the above CNT and a binder resin. Condition (1): The drying temperature T of the coated film is 50°C or higher. Condition (2): The time Z from the start of coating the substrate surface with the coating liquid to the start of drying of the coating film is 0.01 seconds or more and 150 seconds or less.

[0013] According to the inventors' studies, using CNTs as a conductive material is considered more suitable for suppressing the degradation of the antistatic layer due to exposure to high-temperature environments compared to using conductive polymers. The high oxidation resistance of CNTs may contribute to the suppression of degradation. Furthermore, studies have shown that in-plane variations in surface resistivity of the formed antistatic layer, and changes in the resistance of the antistatic layer due to exposure to harsh environments such as automotive applications, can be factors in display defects of image display devices. It is presumed that using the above-mentioned specific CNTs as a conductive material and drying the coating film to satisfy conditions (1) and (2) contribute to suppressing the above-mentioned in-plane variations and changes in resistance. CNTs have strong shape anisotropy and are more prone to aggregation than conductive polymers. Using the above-mentioned specific CNTs and drying them to satisfy conditions (1) and (2) suppresses the aggregation of CNTs during coating of the coating liquid, drying of the coating film, and exposure of the formed antistatic layer to high-temperature environments, thereby potentially suppressing the above-mentioned changes in resistance. Furthermore, drying the material to satisfy condition (2) may suppress the in-plane variation described above.

[0014] The drying temperature T is the temperature of the atmosphere used to dry the coating film. When drying the coating film using a drying oven, the drying temperature T may be the set temperature of the drying oven.

[0015] The drying temperature T may be 55°C or higher, 60°C or higher, 65°C or higher, 70°C or higher, greater than 70°C, 72°C or higher, 75°C or higher, 77°C or higher, 80°C or higher, 82°C or higher, or even 85°C or higher. The upper limit of the drying temperature T is, for example, 130°C or lower, and may be 125°C or lower, 120°C or lower, 115°C or lower, 110°C or lower, 105°C or lower, 100°C or lower, or even 95°C or lower. Limiting the upper limit of the drying temperature T can, for example, contribute to suppressing curling of the substrate due to heat during drying. Limiting the upper limit is particularly suitable when using a film that is prone to curling due to heat (e.g., a polarizing film) as the substrate.

[0016] Time Z corresponds to the time from coating to drying. Time Z is defined as the time from the start of coating the substrate surface with the coating liquid to the start of drying of the coated film. The start of coating can be defined as the point at which coating begins to be applied to the substrate surface with a predetermined thickness. The point at which drying of the coated film begins can be defined as the point at which the coated film is placed in a drying atmosphere. For example, when the coated film is placed in a drying oven or passed through a drying oven to dry it, the start of drying can be defined as the point at which the coated film is placed in a drying oven set to a drying atmosphere, or the point at which the coated film enters a drying oven set to a drying atmosphere.

[0017] The lower limit of time Z may be 0.05 seconds or more, 0.1 seconds or more, 0.3 seconds or more, 0.5 seconds or more, 0.8 seconds or more, 1 second or more, 1.5 seconds or more, 2 seconds or more, 2.5 seconds or more, 3 seconds or more, 3.5 seconds or more, 4 seconds or more, 4.5 seconds or more, 5 seconds or more, 6 seconds or more, 7 seconds or more, 8 seconds or more, 9 seconds or more, and even 10 seconds or more. The upper limit of time Z may be 140 seconds or less, 130 seconds or less, 120 seconds or less, 110 seconds or less, 100 seconds or less, 90 seconds or less, 80 seconds or less, 70 seconds or less, 60 seconds or less, 50 seconds or less, 45 seconds or less, 40 seconds or less, 35 seconds or less, 30 seconds or less, 25 seconds or less, 20 seconds or less, 18 seconds or less, 15 seconds or less, 14 seconds or less, 13 seconds or less, 12 seconds or less, 11 seconds or less, and even 10 seconds or less.

[0018] The coating liquid can be applied by various coating methods. For example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, lip coating, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, and extrusion coating methods using die coaters are available. In coating methods such as gravure coating, where a coating to a predetermined thickness can be achieved simply by adhering the coating liquid to the surface of the substrate, the start of coating can be defined as the moment the coating liquid adheres to the surface of the substrate. In coating performed while the substrate is being transported, the start of coating may be defined as the moment the substrate passes the point where the coating liquid adheres. Furthermore, in coating methods that require not only applying a coating liquid to the surface of a substrate but also adjusting the coating thickness afterward in order to coat the substrate to a predetermined thickness, the start of coating can be defined as the point at which the adjustment of the coating thickness begins (for example, in bar coating or knife coating performed while the substrate is being transported, the point at which the coating liquid attached to the surface of the substrate passes through the gap, or in bar coating performed with the substrate fixed, the point at which the adjustment of the coating thickness by sliding the bar in contact with the coating liquid on the surface of the substrate begins).

[0019] The amount of coating solution applied may be adjusted, for example, by considering the solid content concentration of the coating solution and the desired thickness of the antistatic layer. However, according to the inventors' studies, the solid content concentration of the coating solution and the thickness of the coating film formed on the surface of the substrate may affect the in-plane variation of the surface resistivity in the formed antistatic layer and the change in resistance of the antistatic layer due to exposure to harsh environments.

[0020] The solid content concentration of the coating solution is, for example, 0.05% by weight or more and 5% by weight or less. The lower limit of the solid content concentration may be 0.08% by weight or more, 0.1% by weight or more, 0.15% by weight or more, 0.2% by weight or more, 0.25% by weight or more, and even 0.3% by weight or more. The upper limit of the solid content concentration may be 4.5% by weight or less, 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, 1.5% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.6% by weight or less, 0.5% by weight or less, and even 0.4% by weight or less. The solid content concentration may be 0.2% by weight or more and 2.5% by weight or less.

[0021] The thickness of the coating film formed on the surface of the substrate is, for example, 0.5 μm or more and 50 μm or less. The upper limit of the thickness may be 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 18 μm or less, 15 μm or less, 13 μm or less, 12 μm or less, 11 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, and even 5 μm or less. The lower limit of the thickness may be 0.8 μm or more, 1 μm or more, 1.2 μm or more, 1.4 μm or more, 1.5 μm or more, 1.7 μm or more, 1.9 μm or more, and even 2 μm or more. The thickness may be 1 μm or more and 12 μm or less; in other words, in the first manufacturing method, a coating film with a thickness of 1 μm or more and 12 μm or less may be formed on the surface of the substrate.

[0022] The drying time H of the coating film can be set arbitrarily, as long as the antistatic layer is ultimately formed after the removal of the solvent from the coating film. The drying time H is, for example, 10 seconds or more and 150 seconds or less. In the first manufacturing method, the coating film may be dried to satisfy the following condition (3) in addition to the above conditions (1) and (2). Condition (3): Drying temperature H of the coated film is 10 seconds or more and 150 seconds or less.

[0023] The drying time H can be defined as the time from when the coated film is placed in a drying atmosphere until it is removed from the drying atmosphere. For example, when drying a coated film in a drying oven, the drying time H can be defined as the time from when the coated film is placed in the drying oven set to a drying atmosphere until the dried coated film is removed from the drying oven. Alternatively, when drying a coated film by passing it through a drying oven, the drying time H can be defined as the time from when the coated film enters the drying oven set to a drying atmosphere until it exits the drying oven.

[0024] The product T·H (°C·seconds) of the drying temperature T and drying time H of the coated film may be 2500 or more, 3000 or more, 3500 or more, 4000 or more, 4500 or more, or even 5000 or more.

[0025] The coated film can be dried, for example, by a drying oven. However, the drying method is not limited as long as it satisfies the above conditions (1) to (3).

[0026] The temperature of the atmosphere in which the substrate and the coating film are placed from the start of coating the substrate surface with the coating liquid until the start of drying of the coating film is usually 50°C or lower, but may be 45°C or lower, 40°C or lower, 30°C or lower, or even 25°C or lower. The temperature of the atmosphere may also be room temperature (25±5°C).

[0027] In the first manufacturing method, the formation of the coating film and the drying of the formed coating film may be carried out while conveying a strip-shaped substrate. The strip-shaped substrate may be unwound from a roll. Alternatively, in the first manufacturing method, the formation and drying of the coating film may be carried out without conveying the substrate. For example, the formation and drying of the coating film may be carried out on a single-leaf substrate.

[0028] In the first manufacturing method, the surface of the substrate may be surface-treated before applying the coating liquid. In other words, the coating liquid may be applied to the surface of a substrate that has been surface-treated. Depending on the type of surface treatment, for example, plasma treatment or corona treatment is suitable for improving the adhesion of the antistatic layer to the substrate. Examples of surface treatments are plasma treatment and corona treatment. In the first manufacturing method, the coating liquid may be applied to the surface of the substrate without surface treatment. Surface treatment can be carried out by known methods.

[0029] ≪1-1. Coating Liquid≫ <1-1-a.CNT> The coating solution contains single-layer CNTs with a length of 3 μm or more and less than 300 μm. The upper limit of length may be 290 μm or less, 275 μm or less, 250 μm or less, 225 μm or less, 200 μm or less, 175 μm or less, 150 μm or less, 125 μm or less, 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, less than 10 μm, 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, and even 5 μm or less. The lower limit of length may be 3.5 μm or more, 4 μm or more, and even 4.5 μm or more. The length of carbon nanotubes (CNTs) can be determined by observation using an atomic force microscope (AFM) or a scanning electron microscope (SEM).

[0030] The diameter (outer diameter) of the CNT is, for example, 0.1 to 50 nm, but may also be 0.2 to 40 nm, 0.25 to 30 nm, 0.3 to 20 nm, 0.4 to 15 nm, or even 0.5 to 10 nm. The diameter may also be 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4.5 nm or less, 4 nm or less, 3.5 nm or less, 3 nm or less, 2.5 nm or less, or even 2 nm or less. The diameter of the CNT can be specified in accordance with the provisions of ISO / TS10868:2017.

[0031] The coating solution may contain single-layer carbon nanotubes (CNTs) with a length of 3 μm or more and less than 300 μm, and a diameter of 10 nm or less.

[0032] The amount of CNTs in the coating solution is, for example, 0.1 to 5 parts by weight, with the amount of solids in the coating solution being 100 parts by weight. The lower limit of the content may be 0.2 parts by weight or more, 0.4 parts by weight or more, 0.5 parts by weight or more, 0.7 parts by weight or more, or even 0.8 parts by weight or more. The upper limit of the content may be 4.5 parts by weight or less, 4 parts by weight or less, 3.5 parts by weight or less, 3 parts by weight or less, 2.5 parts by weight or less, 2 parts by weight or less, or even 1.5 parts by weight or less.

[0033] The coating solution may contain only the above-mentioned CNTs as the conductive material, or it may contain the above-mentioned CNTs and other conductive materials. Examples of other conductive materials include CNTs other than the above-mentioned CNTs, conductive polymers, composites of conductive polymers and dopants, conductive fine particles, carbon materials, ionic surfactants, and ionic compounds. Examples of carbon materials include carbon black such as acetylene black and Ketjenblack, natural graphite, and artificial graphite.

[0034] <1-1-b. Binder Resin> The coating solution contains a binder resin. The binder resin can contribute to improving the film-forming properties of the antistatic layer and to improving the adhesion and bonding (anchoring force) of the antistatic layer to the substrate.

[0035] Examples of binder resins include oxazoline group-containing polymers, polyurethane resins, polyester resins, acrylic resins, polyether resins, cellulose resins, polyvinyl alcohol resins, epoxy resins, polyvinylpyrrolidone, polystyrene resins, polyethylene glycol, and pentaerythritol. Preferably, the binder resin is an oxazoline group-containing polymer, a polyurethane resin, a polyester resin, or an acrylic resin, and particularly preferably a polyurethane resin and / or an acrylic resin. The coating liquid may contain one or more binder resins, or only one. The combination of two or more binder resins may be a combination of polyurethane resin and acrylic resin.

[0036] The binder resin content in the coating liquid is, for example, 1 part by weight or more, with the amount of solids in the coating liquid being 100 parts by weight, and may be 10 parts by weight or more, 25 parts by weight or more, 50 parts by weight or more, 60 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, 85 parts by weight or more, 90 parts by weight or more, 92 parts by weight or more, 94 parts by weight or more, 95 parts by weight or more, 96 parts by weight or more, 97 parts by weight or more, 98 parts by weight or more, and even 99 parts by weight or more. The upper limit of the content is, for example, 99.9 parts by weight or less, and may be 99.8 parts by weight or less, 99.7 parts by weight or less, 99.5 parts by weight or less, 99.4 parts by weight or less, and even 99.2 parts by weight or less.

[0037] The glass transition temperature (Tg) of the binder resin may be 0°C or higher, and may be 20°C or higher, 30°C or higher, 40°C or higher, 50°C or higher, 55°C or higher, or even 60°C or higher. The upper limit of Tg is, for example, 100°C or lower. In other words, the coating solution may contain a binder resin with a Tg of 0°C or higher. According to the inventors' studies, when using a binder resin, having the binder resin's Tg within the above range may contribute to suppressing the change in surface resistivity of the antistatic layer before and after the DIN test described later. It is presumed that the higher the binder resin's Tg, the more the thermal movement of the conductive material contained in the antistatic layer and the resulting aggregation and orientation are suppressed. Aggregation and orientation can improve the non-uniformity of the conductive material inside the antistatic layer and change the surface resistivity. The suppression of the change in surface resistivity based on the binder resin's Tg may be based on the suppression of the movement of the conductive material during the heating cycle of the DIN test. In this specification, the Tg of polymers refers to the Tg determined from Fox's formula based on the monomer component composition, unless otherwise specified. In this specification, the Tg of resins (including binder resins) refers to the Tg determined by differential scanning calorimetry (DSC), unless otherwise specified. The DSC measurement conditions are as follows: • Atmosphere gas: Nitrogen (50 mL / min) • Measurement temperature range: 0℃ → 100℃ • Heating rate: 10°C / min • Sample volume: Approximately 3 mg (For the sample container, for example, an aluminum Tzero pan can be used.)

[0038] When a coating liquid contains a binder with a Tg of 0°C or higher, the proportion of the binder resin with a Tg of 0°C or higher to the total amount of binder resin contained may be 50% by weight or more, and may be 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, 91% by weight or more, 92% by weight or more, 93% by weight or more, and even 94% by weight or more. The upper limit of this proportion is, for example, 100% by weight or less, and may be 99% by weight or less, 98% by weight or less, 97% by weight or less, 96% by weight or less, and even 95% by weight or less.

[0039] The coating solution may contain binder resins with a Tg of less than 0°C, especially if it contains two or more types of binder resins. For example, the coating solution may contain binder resins with a Tg of 0°C or higher and binder resins with a Tg of less than 0°C. The lower limit of the Tg for binder resins with a Tg of less than 0°C is, for example, -70°C or higher, and may be -60°C or higher, -50°C or higher, -45°C or higher, or even -40°C or higher. Depending on the composition of the coating solution, binder resins with a Tg of less than 0°C may contribute to improving the film-forming properties and the dispersibility of CNTs when forming an antistatic layer from the coated film. When a coating solution contains binder resins with a Tg of 0°C or higher and binder resins with a Tg of less than 0°C, the proportion of binder resins with a Tg of less than 0°C to the total amount of binder resins contained may be 50% by weight or less, and may be 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 6% by weight or less, or even 5% by weight or less. The lower limit of this proportion is, for example, 1% by weight or more, and may be 2% by weight or more, 3% by weight or more, 4% by weight or more, or even 5% by weight or more.

[0040] The coating solution may contain a single layer of CNTs with a length of 3 μm or more and less than 300 μm, and a binder resin with a Tg of 0°C or higher.

[0041] <1-1-c. Leveling agent> The coating liquid may contain a leveling agent. However, the amount of leveling agent in the coating liquid may be small. According to the inventors' studies, a small amount of leveling agent may be particularly suitable for suppressing the above-mentioned resistance change in the formed antistatic layer. The amount of leveling agent in the coating liquid may be, for example, 25 parts by weight or less, based on 100 parts by weight of solids contained in the coating liquid, and may also be 23 parts by weight or less, 20 parts by weight or less, 18 parts by weight or less, 15 parts by weight or less, 13 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, and even 0.1 parts by weight or less. The coating liquid may not contain a leveling agent substantially. The coating solution may be substantially free of leveling agents, or it may contain leveling agents in an amount of 8 parts by weight or less, based on 100 parts by weight of solids contained in the coating solution. In this specification, "substantially free of leveling agents" means that the above-mentioned content is less than 0.01 parts by weight.

[0042] According to the inventors' studies, shortening time Z may be particularly suitable for suppressing in-plane variation in the surface resistivity of the formed antistatic layer, especially when the leveling agent content in the coating liquid is small. From this perspective, in the first manufacturing method, the coating liquid may substantially contain no leveling agent, or it may contain a leveling agent in an amount of 8 parts by weight or less, based on 100 parts by weight of solids contained in the coating liquid, and the coated film may be dried to satisfy the condition that time Z is 15 seconds or less. In this case, the leveling agent content may be 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, and even 0.1 parts by weight or less. Time Z may be 14 seconds or less, 13 seconds or less, 12 seconds or less, 11 seconds or less, and even 10 seconds or less.

[0043] The coating solution may contain one or more leveling agents.

[0044] Examples of leveling agents include ester-based leveling agents, polyether-based leveling agents, fluorine-based leveling agents, silicone-based leveling agents, and acrylic-based leveling agents. Among these, ester-based leveling agents having ester bonds and polyether-based leveling agents having ether bonds are preferred because they readily interact with CNTs.

[0045] Examples of ester-based leveling agents include polyester-modified acrylic group-containing polydimethylsiloxane, polyester-modified polydimethylsiloxane, and polyester polyols.

[0046] Examples of polyether-based leveling agents include cellulose ether; pullulan; polyethylene glycol; silicone-modified polyethers such as polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, and polyether-modified acrylic group-containing polydimethylsiloxane; polyglycerin; alkyl ether derivatives such as polyether polyols, polyoxyethylene-polyoxypropylene condensates, polyoxyethylene alkylphenyl ethers, and lauryl alcohol alkoxylates; and alkyl ether sulfates.

[0047] Examples of fluorine-based leveling agents include perfluoropolyether-modified polydimethylsiloxane, perfluoropolyester-modified polydimethylsiloxane, perfluorobutanesulfonic acid, oligomers containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, perfluoroalkyl group-containing carboxylates, and perfluoroalkyl group- and phosphate group-containing phosphate esters.

[0048] Examples of silicone-based leveling agents include polysiloxanes, reactive polysiloxanes with the introduction of reactive groups such as amino groups, epoxy groups, hydroxyl groups, and carboxyl groups, and non-reactive polysiloxanes with the introduction of non-reactive groups such as alkyl groups, ester groups, aralkyl groups, phenyl groups, and polyether groups.

[0049] An example of an acrylic leveling agent is an acrylic copolymer composed of silicone and acrylic.

[0050] However, leveling agents other than those exemplified above can also be used.

[0051] <1-1-d. Solvent> Examples of solvents for the coating solution are water and organic solvents. The organic solvent may be water-soluble. The solvent may be a single solvent or a mixed solvent containing two or more solvents. An example of a mixed solvent is a solvent containing water and a water-soluble organic solvent. Examples of water-soluble organic solvents are alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol. The water-soluble organic solvent may also be isopropanol (IPA). According to the inventors' studies, combining a single layer of CNTs with a length of 3 μm or more and less than 300 μm with a single solvent may contribute to suppressing the above-mentioned resistance change of the antistatic layer. The single solvent is preferably water. Furthermore, studies suggest that the use of a single solvent, particularly water, may contribute to improving the uniformity of CNTs in the antistatic layer.

[0052] <1-1-e. Dispersant> The coating solution may contain a dispersant for CNTs. The dispersant is not particularly limited as long as it can improve the dispersibility of CNTs in the coating solution.

[0053] ≪1-2. Base material≫ The substrate is typically in the form of a film. The thickness of the film-like substrate is usually 5 to 200 μm, preferably about 5 to 100 μm.

[0054] Examples of constituent materials for the base material include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film; porous materials such as paper, cloth, and nonwoven fabric; nets, foamed sheets, metal foils, and laminates thereof.

[0055] The substrate may be a release film. This configuration is suitable for transferring an antistatic layer formed on the release film to other components. If transferred to an optical film, it is also possible to form an optical laminate containing the optical film and the antistatic layer. The surface of the substrate, which is a release film, may be subjected to various treatments such as release treatment as needed. Various release agents such as silicone-based, fluorine-based, long-chain alkyl-based, and fatty acid amide-based agents, as well as particles such as silica powder, can be used for the release treatment.

[0056] The substrate may be an optical film. This configuration is suitable for the direct formation of an optical laminate comprising an optical film and an antistatic layer.

[0057] The optical film includes, for example, at least one selected from the group consisting of polarizing films and phase difference films. The optical film may include a polarizing film. In other words, the substrate may include a polarizing film, or it may be a polarizing film. The optical film may be a laminated film including a polarizing film and / or a phase difference film. The optical film may include a glass film.

[0058] <1-2-a. Polarizing film> A polarizing film includes a polarizer. The polarizing film includes a polarizer and a protective film (transparent protective film) placed on at least one side of the polarizer. The protective film is usually placed in contact with the main surface of the polarizer. The polarizer may be placed between two protective films. The protective film may be placed on each of the two sides of the polarizer. The protective film may be a single layer or a laminate of two or more layers.

[0059] The polarizer is not particularly limited and includes, for example, hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and partially saponified ethylene-vinyl acetate copolymer films, on which dichroic substances such as iodine and dichroic dyes are adsorbed and then uniaxially stretched; and polyene-based oriented films such as dehydrated polyvinyl alcohol products and dehydrochlorinated polyvinyl chloride products. Typically, the polarizer consists of a polyvinyl alcohol-based film (polyvinyl alcohol-based films include partially saponified ethylene-vinyl acetate copolymer films) and a dichroic substance such as iodine.

[0060] The thickness of the polarizer is not particularly limited and may be, for example, 80 μm or less, but may also be 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the polarizer thickness is not particularly limited and may be, for example, 1 μm or more, but may also be 5 μm or more, 10 μm or more, or even 15 μm or more. Thin polarizers (for example, with a thickness of 20 μm or less) have suppressed dimensional changes and can contribute to improving the durability of the optical laminate, especially its durability at high temperatures.

[0061] As the material for the protective film, for example, a thermoplastic resin that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc., can be used. Specific examples of such thermoplastic resins include cellulose resins such as triacetylcellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material for the protective film may also be a thermosetting resin or an ultraviolet-curable resin such as (meth)acrylic, urethane, acrylic-urethane, epoxy, or silicone-based resin. If the polarizing film has two protective films, the materials of the two protective films may be the same or different. For example, a protective film made of a thermoplastic resin may be bonded to one main surface of the polarizer via an adhesive, and a protective film made of a thermosetting resin or an ultraviolet-curable resin may be bonded to the other main surface of the polarizer. The protective film may contain one or more additives. Examples of additives include UV absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0062] The moisture permeability of the protective film is not particularly limited, but is 200g / (m²). 2 It may be less than 50g / (m 2It may be less than or equal to (day). In this case, it is possible to suppress the intrusion of moisture from the air into the polarizing film and suppress changes in the moisture content of the polarizing film. This suppresses the occurrence of curling and dimensional changes in the polarizing film. In addition, when a protective film with moisture permeability limited to the above range is placed between an adhesive sheet and a polarizer, it can contribute to inhibiting the movement of radicals from the adhesive sheet at high temperatures. Examples of materials that form a protective film with low moisture permeability include polyester polymers, polycarbonate polymers, arylate polymers, amide polymers, olefin polymers, cyclic olefin polymers, (meth)acrylic polymers, and mixtures thereof.

[0063] The moisture permeability of protective films can be measured according to the moisture permeability test (cup method) of JIS Z0208:1976, using the following method. First, the protective film is cut to a diameter of 60 mm to prepare the sample. Next, the sample is placed in a moisture permeability cup containing approximately 15 g of calcium chloride. This moisture permeability cup is placed in a constant temperature chamber set to 40°C and 92% RH and left for 24 hours to perform the moisture permeability test. The moisture permeability of the protective film can be determined by measuring the increase in the weight of calcium chloride before and after the test.

[0064] The thickness of the protective film can be determined as appropriate, but generally it is around 10 to 200 μm, considering factors such as strength, workability (handling, etc.), and thinness.

[0065] The polarizer and protective film are typically bonded together via a water-based adhesive. Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl latex, water-based polyurethane, and water-based polyester. Other adhesives besides those mentioned above include UV-curing adhesives and electron beam-curing adhesives. Electron beam-curing adhesives for polarizers exhibit suitable adhesion to various protective films. The adhesive may also contain metal compound fillers.

[0066] In polarizing films, a phase difference film or the like can be formed on the polarizer instead of a protective film. Furthermore, another protective film, a phase difference film, or the like can be added on top of the protective film.

[0067] A polarizing film can be identified as a laminate containing polarizers, in which each layer is bonded to the others by an adhesive.

[0068] Regarding the protective film, a hard coat layer may be provided on the surface that is in contact with the polarizer and the surface facing it, and treatments for purposes such as anti-reflection, anti-sticking, diffusion, and anti-glare may be applied.

[0069] The polarizing film may also be a circularly polarizing film.

[0070] <1-2-b. Phase difference film> As the phase difference film, one obtained by stretching a polymer film or one obtained by oriented and immobilizing a liquid crystal material can be used. The phase difference film has birefringence in the in-plane direction and / or in the thickness direction, for example.

[0071] Examples of phase difference films include anti-reflective phase difference films (see Japanese Patent Publication No. 2012-133303

[0221] ,

[0222] ,

[0228] ), phase difference films for viewing angle compensation (see Japanese Patent Publication No. 2012-133303

[0225] ,

[0226] ), and tilt-oriented phase difference films for viewing angle compensation (see Japanese Patent Publication No. 2012-133303

[0227] ).

[0072] As for the phase difference film, any known phase difference film can be used, as long as it substantially possesses the above-mentioned functions, for example, the phase difference value, arrangement angle, three-dimensional birefringence, whether it is single-layer or multi-layer, etc.

[0073] The thickness of the phase difference film is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 1 to 9 μm, and particularly preferably 3 to 8 μm.

[0074] A phase difference film, for example, is composed of two layers: a quarter-wave plate and a half-wave plate, on which liquid crystal material is oriented and fixed.

[0075] The base material is not limited to the examples above.

[0076] ≪1-3. Antistatic layer≫ The formed antistatic layer will now be described. In the first manufacturing method, the antistatic layer described below may be formed.

[0077] The content of the above-mentioned CNTs (single-layer CNTs with a length of 3 μm or more and less than 300 μm) in the antistatic layer is, for example, 0.01 to 50.0 mg / m². 2 Therefore, 0.1~10.0 mg / m² 2 It is also possible that the above CNTs are present in the total solid content of the antistatic layer, for example, 0.1 to 5% by weight. The lower limit of the percentage may be 0.2% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 0.7% by weight or more, and even 0.8% by weight or more. The upper limit of the percentage may be 4.5% by weight or less, 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, and even 1.5% by weight or less. From the viewpoint of suppressing the loss of total light transmittance when an optical laminate containing an optical film is formed, it is preferable that the above percentage be small.

[0078] The proportion of binder resin in the total solid content of the antistatic layer is, for example, 1% by weight or more, and may be 10% by weight or more, 25% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, 92% by weight or more, 94% by weight or more, 95% by weight or more, 96% by weight or more, 97% by weight or more, 98% by weight or more, and even 99% by weight or more. The upper limit of the proportion is, for example, 99.9% by weight or less, and may be 99.8% by weight or less, 99.7% by weight or less, 99.5% by weight or less, 99.4% by weight or less, and even 99.2% by weight or less.

[0079] The proportion of the leveling agent in the total solid content contained in the antistatic layer is, for example, 25% by weight or less, 23% by weight or less, 20% by weight or less, 18% by weight or less, 15% by weight or less, 13% by weight or less, 11% by weight or less, 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.5% by weight or less, and further may be 0.1% by weight or less. The antistatic layer may not substantially contain a leveling agent. In this specification, that the antistatic layer does not substantially contain a leveling agent means that the above proportion is less than 0.01% by weight.

[0080] The thickness of the antistatic layer is, for example, 5 to 1500 nm, 1400 nm or less, 1300 nm or less, 1200 nm or less, 1100 nm or less, 1000 nm or less, 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 180 nm or less, 150 nm or less, 120 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 55 nm or less, 50 nm or less, 45 nm or less, 40 nm or less, 35 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, 19 nm or less, 18 nm or less, 17 nm or less, 16 nm or less, and further may be 15 nm or less. The thickness may be 6 nm or more, 7 nm or more, 8 nm or more, 9 nm or more, 10 nm or more, 11 nm or more, 12 nm or more, 13 nm or more, 14 nm or more, and further may be 15 nm or more. In the first manufacturing method, an antistatic layer having a thickness of 5 nm or more and 200 nm or less may be formed.

[0081] The surface resistivity of the antistatic layer is, for example, 1.0×10 9 Ω / sq or less, 9.0×10 8 Ω / sq or less, 8.0×10 8 Ω / sq or less, 7.0×10 8 Ω / sq or less, 6.0×10 8 Ω / sq or less, 5.0×10 8 Ω / sq or less, 4.0×10 8 Ω / sq or less, 3.0×10 8Ω / □ or less, 2.5×10 8 Ω / □ or less, 2.0×10 8 Ω / □ or less, 1.5×10 8 Ω / □ or less, 1.0×10 8 Ω / □ or less, 9.0×10 7 Ω / □ or less, 8.0×10 7 Ω / □ or less, 7.0×10 7 Ω / □ or less, 6.0×10 7 Ω / □ or less, 5.0×10 7 Ω / □ or less, 4.0×10 7 Ω / □ or less, 3.0×10 7 Ω / □ or less, 2.0×10 7 Ω / □ or less, and even 1.5 × 10 7 It may be less than or equal to Ω / □. The lower limit of surface resistivity is, for example, 1.0 × 10⁻⁶. 5 It is greater than or equal to Ω / □, and 2.0 × 10 5 Ω / □ or more, 3.0×10 5 Ω / □ or more, 4.0×10 5 Ω / □ or more, 5.0×10 5 Ω / □ or more, 6.0×10 5 Ω / □ or more, 7.0×10 5 Ω / □ or more, 8.0×10 5 Ω / □ or more, 9.0×10 5 Ω / □ or more, 1.0×10 6 Ω / □ or more, 2.0×10 6 Ω / □ or more, 3.0×10 6 Ω / □ or more, 4.0×10 6 Ω / □ or more, 5.0×10 6 Ω / □ or more, 6.0×10 6 Ω / □ or more, 7.0×10 6 Ω / □ or more, 8.0×10 6 Ω / □ or more, 9.0×10 6 Ω / □ or greater, and even 1.0 × 10 7 It may be Ω / □ or greater. In the first manufacturing method, 3.0 × 10 8 An antistatic layer having a surface resistivity of Ω / □ or less may be formed.

[0082] The antistatic layer may satisfy the following formula (I). In formula (I), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test condition: Z-IN1) specified in German industrial standard DIN75220, respectively. In the first manufacturing method, an antistatic layer satisfying the following formula (I) may be formed. -2 ≤ logB - logA ≤ 2 (I)

[0083] As described above, our inventors' studies have shown that changes in the resistance of the antistatic layer due to exposure to harsh environments such as those in automotive applications can be a cause of display failure in image display devices. The weather resistance test specified in DIN75220 (hereinafter referred to as the "DIN test") is a weather resistance test that takes the above-mentioned harsh environments into consideration. In antistatic layers that satisfy formula (I), the change in surface resistivity before and after the DIN test is suppressed.

[0084] In the DIN test, test condition Z-IN1 is a test for Indoor (Zone 1) and refers to a cycle test (Z) consisting of a 15-day dry climate cycle followed by a 10-day humid climate cycle. In the dry climate cycle, one cycle consists of (1) 8 hours of UV irradiation in an atmosphere of 80°C and 20% relative humidity, (2) 3.5 hours of standing in an atmosphere of 10°C and 60% relative humidity (without UV irradiation), (3) 8 hours of UV irradiation in an atmosphere of 80°C and 20% relative humidity, and (4) 3.5 hours of standing in an atmosphere of 10°C and 60% relative humidity (without UV irradiation). This cycle is repeated for 15 days. However, between (4) of one cycle and (1) of the next cycle, the sample is left at room temperature (23°C) for 1 hour. In the humid climate cycle, one cycle consists of (1) leaving the sample in an atmosphere of -10°C (without UV irradiation) for 5 hours, (2) irradiating the sample with UV light in an atmosphere of 80°C and 50% relative humidity for 12 hours, and (3) leaving the sample in an atmosphere of -10°C (without UV irradiation) for 6 hours. This cycle is repeated for 10 days. However, between (3) of one cycle and (1) of the next cycle, the sample is left at room temperature for 1 hour. Indoor (Zone 1) refers to the classification of automotive parts and materials in terms of their mounting location inside the vehicle, meaning interior parts and materials that are exposed to high temperatures but with lower sunlight irradiation intensity than exterior parts. The illuminance of the metal halide lamp used for UV irradiation is 830 W / m². 2 Let's assume that.

[0085] The lower limit of logB-logA in equation (I) may be -1.9 or greater, -1.8 or greater, -1.7 or greater, -1.6 or greater, -1.5 or greater, -1.4 or greater, -1.3 or greater, -1.2 or greater, -1.15 or greater, -1.1 or greater, -1.05 or greater, -1.0 or greater, -0.95 or greater, -0.9 or greater, -0.85 or greater, -0.8 or greater, -0.75 or greater, -0.7 or greater, -0.65 or greater, -0.6 or greater, -0.55 or greater, -0.5 or greater, -0.45 or greater, -0.4 or greater, -0.35 or greater, -0.3 or greater, -0.25 or greater, -0.2 or greater, -0.15 or greater, -0.1 or greater, and even -0.05 or greater. The upper limit of logB-logA may be 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.15 or less, 1.1 or less, 1.05 or less, 1.0 or less, 0.95 or less, 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.1 or less, and even 0.05 or less.

[0086] The ranges that the surface resistivity A (surface resistivity before DIN testing) and surface resistivity B (surface resistivity after DIN testing) of the antistatic layer can each take are the same as the range of surface resistivity that the antistatic layer can take as described above. However, surface resistivity B may be the same as surface resistivity A, or smaller than surface resistivity A. In other words, the relationship expressed by the formula: surface resistivity B ≤ surface resistivity A may hold between surface resistivity A and surface resistivity B.

[0087] The surface resistivity of the antistatic layer can be measured using a high-resistivity resistivity meter (for example, the HighResta series manufactured by Mitsubishi Chemical Analytec Co., Ltd.) in accordance with the method specified in Japanese Industrial Standard (JIS) K6911:1995. However, the surface resistivity measurement should be performed with an applied voltage of 10V, an application time of 10 seconds, and an ambient temperature of 25±3℃.

[0088] Solid components in the coating solution, such as carbon nanotubes (CNTs) and binder resins, are typically also present in the formed antistatic layer. Furthermore, their amounts are maintained unless they are components that are removed during drying by volatilization or decomposition.

[0089] The formed antistatic layer can be used in optical laminates.

[0090] ≪≪2. Method for Manufacturing Optical Laminates 1≫≫ The first method for manufacturing an optical laminate according to this embodiment (hereinafter referred to as the "second manufacturing method") is a method for manufacturing an optical laminate that includes an optical film and an antistatic layer in that order. In the second manufacturing method, the antistatic layer is formed by the first manufacturing method.

[0091] The second manufacturing method may be carried out, for example, by laminating an optical film onto an antistatic layer formed on a substrate by the first manufacturing method, or by transferring the antistatic layer formed on the substrate to the optical film. Alternatively, it may be carried out by forming an antistatic layer on the optical film which is the substrate. Examples of the substrate and optical film are as illustrated in the description of the first manufacturing method. The optical film may include a polarizing film, in which case an optical laminate including the polarizing film and the antistatic layer can be formed.

[0092] The second manufacturing method may be carried out by methods other than those exemplified above.

[0093] An example of an optical laminate that can be formed by the second manufacturing method is shown in Figure 1. The optical laminate 3(3A) in Figure 1 includes one layer each of an antistatic layer 1 and an optical film 4. The optical laminate 3A includes the optical film 4 and the antistatic layer 1 in this order. The optical laminate 3A has a structure in which the optical film 4 and the antistatic layer 1 are laminated in this order. The optical laminate 3A may be bonded to an object such as an image display panel via, for example, an adhesive sheet.

[0094] The optical film 4 in Figure 1 is in contact with the antistatic layer 1. However, other films and / or layers may be placed between the optical film 4 and the antistatic layer 1. Also, the optical film 4 in Figure 1 is formed over the entire surface of one main surface of the antistatic layer 1 when viewed in the lamination direction. However, the optical film 4 may be formed on a portion of one main surface of the antistatic layer 1 when viewed in the lamination direction. In this specification, "main surface" means the surface of the film or layer having the largest area.

[0095] The optical laminate 3 formed by the second manufacturing method may include other layers besides the optical film 4 and the antistatic layer 1. Examples of other layers include adhesive sheets and other optical films such as cover films and protective films. The other layers may also be layers included in known optical laminates.

[0096] ≪≪3. Method for Manufacturing Optical Laminates 2≫≫ The optical laminate manufacturing method 2 of this embodiment (hereinafter referred to as the "third manufacturing method") is a method for manufacturing an optical laminate that includes an optical film, an antistatic layer, and an adhesive sheet in that order. In the third manufacturing method, the antistatic layer is formed by the first manufacturing method.

[0097] The third manufacturing method may be carried out, for example, by the following method. The antistatic layer formed on the substrate by the first manufacturing method is transferred to an optical film, and an adhesive sheet is formed on the transferred antistatic layer. The formation of the adhesive sheet on the antistatic layer may also be performed by transferring a separately formed adhesive sheet. - An antistatic layer is formed on a substrate that is an optical film. An adhesive sheet is formed on the formed antistatic layer. The adhesive sheet may be formed on the antistatic layer by transferring a separately formed adhesive sheet.

[0098] More specifically, the third manufacturing method may be carried out, for example, by the following method. A first laminate consisting of an optical film and an antistatic layer is formed. Separately, a second laminate consisting of a substrate and an adhesive sheet is formed. An optical laminate is manufactured by bonding the adhesive sheet of the second laminate to the antistatic layer of the first laminate.

[0099] The third manufacturing method may be carried out by methods other than those exemplified above.

[0100] Examples of the substrate and optical film are as illustrated in the description of the first manufacturing method. The optical film may be a polarizing film, in which case an optical laminate can be manufactured that includes a polarizing film, an antistatic layer, and an adhesive sheet.

[0101] An example of an optical laminate that can be formed by the third manufacturing method is shown in Figure 2. The optical laminate 3 (3B) in Figure 2 includes one layer each of an antistatic layer 1, an optical film 4, and an adhesive sheet 5. The optical laminate 3B includes the optical film 4, the antistatic layer 1, and the adhesive sheet 5 in this order. The optical laminate 3B has a structure in which the optical film 4, the antistatic layer 1, and the adhesive sheet 5 are laminated in this order. The optical laminate 3B may be bonded to an object such as an image display panel via the adhesive sheet 5, for example.

[0102] The adhesive sheet 5 in Figure 2 is in contact with the antistatic layer 1. However, other films and / or layers may be placed between the adhesive sheet 5 and the antistatic layer 1. Also, the adhesive sheet 5 in Figure 2 is formed on the entire surface of one main surface of the antistatic layer 1 when viewed in the lamination direction. However, the adhesive sheet 5 may be formed on a part of one main surface of the antistatic layer 1 when viewed in the lamination direction.

[0103] The optical film 4 in Figure 2 is in contact with the antistatic layer 1. However, other films and / or layers may be placed between the optical film 4 and the antistatic layer 1. Also, the optical film 4 in Figure 2 is formed on the entire surface of one main surface of the antistatic layer 1 when viewed in the lamination direction. However, the optical film 4 may be formed on a part of one main surface of the antistatic layer 1 when viewed in the lamination direction.

[0104] The optical laminate 3 formed by the third manufacturing method may include layers other than the optical film 4, the antistatic layer 1, and the adhesive sheet 5. Examples of other layers include further adhesive sheets, other optical films such as cover films and protective films, and a release liner that protects the adhesive sheet 5. The other layers may also be layers included in known optical laminates.

[0105] An example of the optical film 4 is as illustrated in the description of the first manufacturing method.

[0106] ≪3-1. Adhesive Sheets≫ The adhesive sheet 5 is typically a layer formed from an adhesive composition (B) containing a polymer (A).

[0107] <3-1-a. Polymer (A)> Examples of polymer (A) include (meth)acrylic polymers, urethane polymers, silicone polymers, and rubber polymers. Polymer (A) is preferably a (meth)acrylic polymer. Adhesive composition (B) may contain a (meth)acrylic polymer as its main component; in other words, adhesive composition (B) may be an acrylic adhesive composition. In this specification, the main component means the component with the largest weight content in the composition. The content of the main component may be, for example, 50% by weight or more, 60% by weight or more, 70% by weight or more, 75% by weight or more, and even 80% by weight or more. In this specification, a (meth)acrylic polymer means a polymer having constituent units derived from (meth)acrylic monomers such as (meth)acrylate. The content of the constituent units in the (meth)acrylic polymer is, for example, 40% by weight or more, and may be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, and even 95% by weight or more. The (meth)acrylic polymer may consist only of constituent units derived from (meth)acrylic monomers. (Meth)acrylic means acrylic and methacrylic. (Meth)acrylate means acrylate and methacrylate.

[0108] Polymer (A) may have a polyether structure. The adhesive composition (B) may contain polymer (A) having a polyether structure as a main component. The polyether structure is a structure that includes at least two ether groups (-O-). The polyether structure may be linear or branched. An example of a polyether structure is a linear or branched alkyl group and at least two ether groups. Polymer (A) may have the polyether structure in the main chain or in the side chains, and it is preferable to have it in the side chains. Polymer (A) may be a (meth)acrylic polymer having a polyether structure in its side chains.

[0109] Polymer (A) may have constituent units having a polyether structure. In such constituent units, the polyether structure may be located in the main chain or in the side chains, and is preferably located in the side chains. Polymer (A) may also have constituent units derived from a (meth)acrylic monomer having a polyether structure in its side chains.

[0110] A polymer (A) having a polyether structure in its side chains may have, for example, a constituent unit derived from monomer A1 shown in the following formula (2). In other words, polymer (A) may have a constituent unit derived from monomer shown in the following formula (2). R in formula (2) 1 R is a hydrogen atom or a methyl group. 2 R is an alkyl group that may be linear or branched, and is preferably a linear alkyl group. The number of carbon atoms in the alkyl group may be 1 to 10, and more preferably 1 to 4. 2 Examples include methyl and ethyl groups. n is an integer from 1 to 15, preferably from 1 to 10, and more preferably from 1 to 5. When n is 1, monomer A1 contains two ether groups, including the "-O-" of the COO group. Monomer A1 is a type of (meth)acrylic monomer, more specifically, a type of (meth)acrylate monomer. R at the end of the side chain 2Focusing on the oxygen group, monomer A1 is also a type of alkoxy-containing (meth)acrylate monomer. The constituent units derived from monomer A1 have a polyether structure in their side chains.

[0111] [ka]

[0112] Examples of monomer A1 include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate, preferably 2-methoxyethyl acrylate (MEA). Constituent units derived from monomer A1 can contribute to a reduction in the surface resistivity of the adhesive sheet 5 formed from the adhesive composition (B).

[0113] The content of constituent units having a polyether structure in polymer (A) may be, for example, 0% by weight or more, and may be 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, and even 50% by weight or more. The upper limit of this content may be, for example, 100% by weight or less, and may be 90% by weight or less, 80% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, and even less than 60% by weight. Furthermore, the content of constituent units derived from monomer A1 in polymer (A) may be within the above range.

[0114] Polymer (A) does not necessarily have to have constituent units having a polyether structure.

[0115] Polymer (A) may have one or more constituent units derived from monomer A2. Monomer A2 may be copolymerizable with monomer A1. Polymer (A) may have both constituent units derived from monomer A1 and constituent units derived from monomer A2.

[0116] Examples of monomer A2 are (meth)acrylic monomers having an alkyl group with 1 to 30 carbon atoms in its side chain. The alkyl group may be linear or branched. Examples of such (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. These are n-octyl(meth)acrylate, isooctyl(meth)acrylate, n-nonyl(meth)acrylate, isononyl(meth)acrylate, n-decyl(meth)acrylate, isodecyl(meth)acrylate, n-dodecyl(meth)acrylate (lauryl(meth)acrylate), n-tridecyl(meth)acrylate, n-tetradecyl(meth)acrylate, pentadecyl(meth)acrylate, hexadecyl(meth)acrylate, heptadecyl(meth)acrylate, and octadecyl(meth)acrylate. The content of the constituent units derived from the above (meth)acrylic monomer in polymer (A) is, for example, 80% by weight or less, and may be 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, or even 5% by weight or less, or even 0% by weight (not having such constituent units).

[0117] Another example of monomer A2 is a hydroxyl group-containing monomer. The hydroxyl group-containing monomer may be a hydroxyl group-containing (meth)acrylic monomer. Examples of hydroxyl group-containing monomers are hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate, as well as (4-hydroxymethylcyclohexyl)-methyl acrylate. From the viewpoint of improving the durability of the adhesive sheet 5 formed from adhesive composition (B), 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred. The content of constituent units derived from hydroxyl group-containing monomers in polymer (A) is, for example, 0.1 to 5% by weight, and may be 3% by weight or less, or even 2% by weight or less. Polymer (A) does not need to contain constituent units derived from hydroxyl group-containing monomers.

[0118] Monomer A2 may be an aromatic ring-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, or an amide group-containing monomer.

[0119] The aromatic ring-containing monomer may be an aromatic ring-containing (meth)acrylic monomer. Examples of aromatic ring-containing monomers are phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, hydroxyethylated β-naphthol (meth)acrylate, and biphenyl (meth)acrylate. During the manufacture and / or use of an image display device containing the optical laminate 3C, birefringence may occur due to the displacement of the adhesive sheet. When birefringence occurs, problems such as light leakage and display unevenness may occur in the image display device. The inclusion of constituent units derived from aromatic ring-containing monomers is suitable for reducing the birefringence that may occur due to the displacement of the adhesive sheet.

[0120] The aromatic ring-containing monomer may also be monomer A3 shown in the following formula (3). R in formula (3) 3 R in formula (3) is either a hydrogen atom or a methyl group. 4 is a phenyl group which may have a hydrogen atom substituted, and is preferably a phenyl group. Substituents for the hydrogen atom are, for example, linear or branched alkyl groups having 1 to 10, and more preferably 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms. n is an integer from 1 to 15, preferably an integer from 1 to 10, and more preferably an integer from 1 to 5. When n is 1, monomer A3 is a type of (meth)acrylic monomer, and more specifically a type of (meth)acrylate monomer. Monomer A3 contains two ether groups, including the "-O-" of the COO group. In other words, the constituent units derived from monomer A3 are also constituent units having a polyether structure. The content of constituent units derived from monomer A3 in polymer (A) shall be included in the content of constituent units having a polyether structure.

[0121] [ka]

[0122] An example of monomer A3 is phenoxyethyl (meth)acrylate.

[0123] Polymer (A) having constituent units derived from monomer A3 can contribute to improving the durability of the optical laminate 3C. Furthermore, polymer (A) having constituent units derived from monomer A3 is suitable for suppressing displacement of the optical film 4 at the edges, even when the optical laminate 3C includes an optical film 4 that may shrink upon heating.

[0124] Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of amino group-containing monomers include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of amide group-containing monomers include acrylamide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylol-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, and mercaptoethyl(meth)acrylamide; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholin, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl group-containing lactam monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

[0125] Monomer A2 may be a polyfunctional monomer. Examples of polyfunctional monomers include polyfunctional acrylates such as hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, vinyl(meth)acrylate, epoxy acrylate, polyester acrylate and urethane acrylate; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate or dipentaerythritol hexa(meth)acrylate.

[0126] The total content of constituent units derived from aromatic ring-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, amide group-containing monomers, and polyfunctional monomers in polymer (A) is preferably 20% by weight or less, more preferably 15% by weight or less, even more preferably 10% by weight or less, and particularly preferably 8% by weight or less. If polymer (A) has such constituent units, the total content may be, for example, 0.01% by weight or more, 1% by weight or more, 2% by weight or more, or even 3% by weight or more. Polymer (A) does not have to have these constituent units. In particular, in polymer (A), the content of constituent units derived from carboxyl group-containing monomers may be less than 0.1% by weight, or even 0% by weight (i.e., polymer (A) may not have such constituent units).

[0127] Other examples of monomer A2 include nitrile group-containing (meth)acrylates such as acrylic acid and (meth)acrylonitrile; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphate group-containing monomers; alicyclic hydrocarbon group-containing (meth)acrylic acid esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0128] The total content of other constituent units derived from monomer A2 in polymer (A) is, for example, 30% by weight or less, may be 10% by weight or less, 5% by weight or less, and preferably 0% by weight (no such constituent units).

[0129] Polymer (A) may have constituent units derived from (meth)acrylic monomers having a glass transition temperature (Tgh) of -55°C or higher when homopolymerized, or constituent units derived from (meth)acrylic monomers having a Tgh of -40°C or higher, or constituent units derived from (meth)acrylic monomers having a Tgh of -30°C or higher, or constituent units derived from (meth)acrylic monomers having a Tgh of -10°C or higher. Examples of the above constituent units are constituent units derived from monomer A3 and constituent units derived from (meth)acrylic monomers having an alkyl group with 1 to 3 carbon atoms in the side chain. Polymer (A) may have at least one constituent unit selected from the group consisting of constituent units derived from monomer A3 and constituent units derived from (meth)acrylic monomers having an alkyl group with 1 to 3 carbon atoms in the side chain. Polymer (A) having the above constituent units can contribute to improving the durability of the optical laminate 3C.

[0130] Polymer (A) can be formed by polymerizing one or more of the above-mentioned monomers by known methods. Monomers and partial polymers of monomers may also be polymerized. Polymerization can be carried out by, for example, solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy ray polymerization. From the viewpoint of forming an adhesive sheet with excellent optical transparency, solution polymerization and active energy ray polymerization are preferred. Polymerization is preferably carried out while avoiding contact between the monomers and / or partial polymers and oxygen. For this purpose, polymerization can be carried out, for example, under an inert gas atmosphere such as nitrogen, or under conditions where oxygen is blocked by a resin film or the like. The polymer (A) to be formed may be in any form such as a random copolymer, block copolymer, or graft copolymer.

[0131] The polymerization system that forms polymer (A) may contain one or more polymerization initiators. The type of polymerization initiator can be selected depending on the polymerization reaction, and may be, for example, a thermal polymerization initiator or a photopolymerization initiator.

[0132] Solvents used in solution polymerization include, for example, esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. However, the solvent is not limited to the above examples. The solvent may be a mixture of two or more solvents.

[0133] Polymerization initiators used in solution polymerization include, for example, azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. Examples of peroxide polymerization initiators include dibenzoyl peroxide and t-butyl permaleate. Among these, the azo polymerization initiator disclosed in Japanese Patent Application Publication No. 2002-69411 is preferred. Examples of such azo polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, and 4,4'-azobis-4-cyanovaleric acid. However, the polymerization initiator is not limited to the above examples. The amount of azo polymerization initiator used is, for example, 0.05 to 0.5 parts by weight per 100 parts by weight of the total amount of monomer, and may also be 0.1 to 0.3 parts by weight.

[0134] The active energy rays used in active energy ray polymerization include, for example, ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet rays. Ultraviolet rays are preferred as the active energy rays. Polymerization by irradiation with ultraviolet rays is also called photopolymerization. The polymerization system for active energy ray polymerization typically includes a photopolymerization initiator. The polymerization conditions for active energy polymerization are not limited as long as polymer (A) is formed.

[0135] Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators. However, the photopolymerization initiators are not limited to the examples above.

[0136] Benzoin ether-based photopolymerization initiators include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Acetophenone-based photopolymerization initiators include, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Alpha-ketol-based photopolymerization initiators include, for example, 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Aromatic sulfonyl chloride-based photopolymerization initiators include, for example, 2-naphthalenesulfonyl chloride. Photoactive oxime-based photopolymerization initiators include, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Benzoin-based photopolymerization initiators include, for example, benzoin. Benzyl-based photopolymerization initiators include, for example, benzyl. Benzophenone-based photopolymerization initiators include, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Ketal-based photopolymerization initiators include, for example, benzyldimethylketal. Thioxanthone-based photopolymerization initiators include, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0137] The amount of photopolymerization initiator used is, for example, 0.01 to 1 part by weight per 100 parts by weight of the total amount of monomer, and may also be 0.05 to 0.5 parts by weight.

[0138] The weight-average molecular weight (Mw) of polymer (A) is, for example, 1 million to 3 million, preferably 1.8 million to 3 million. A weight-average molecular weight of 1 million to 3 million for polymer (A) tends to suppress cracking of the adhesive sheet, as well as the increase in viscosity and the occurrence of gelation. The weight-average molecular weight (Mw) of the polymer in this specification is a value (polystyrene equivalent) based on GPC (gel permeation chromatography) measurements.

[0139] The content of polymer (A) in adhesive composition (B) is, for example, 50% by weight or more in terms of solid content, and may be 60% by weight or more, 70% by weight or more, 75% by weight or more, or even 80% by weight or more. The upper limit of the content is, for example, 99% by weight or less, and may be 97% by weight or less, or even 95% by weight or less.

[0140] <3-1-b. Antistatic agents> The adhesive composition (B) may contain an antistatic agent. The antistatic agent can contribute to reducing the surface resistivity of the adhesive sheet 5. An example of an antistatic agent is an ionic compound such as a salt. The ionic compound may be an ionic liquid that is liquid at room temperature (25°C).

[0141] Examples of ionic compounds include inorganic cationic salts and organic cationic salts. An example of an inorganic cationic salt is an inorganic cation-anion salt. An example of a cation in an inorganic cationic salt is an alkali metal ion. Alkali metal ions include, for example, lithium ions, sodium ions, and potassium ions, and preferably lithium ions. The inorganic cationic salt may also be a lithium salt.

[0142] An example of anion contained in inorganic cation salts is Cl - , Br - , I- , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 - , CF3SO3 - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , (CN)2N - , C4F9SO3 - , C3F7COO - , (CF3SO2)(CF3CO)N - , -O3S(CF2)3SO3 - , and an anion represented by the following general formulas (a) to (d). (a) (C n F 2n+1 SO2)2N - (n is an integer from 1 to 10) (b) CF2(C m F 2m SO2)2N - (m is an integer from 1 to 10) (c) -O3S(CF2) l SO3 - (l is an integer from 1 to 10) (d) (C p F 2p+1 SO2)N - (C q F 2q+1 SO2) (p and q are independently integers from 1 to 10)

[0143] The anion contained in the inorganic cation salt is preferably a fluorine-containing anion, more preferably a fluorine-containing imide anion. Examples of the fluorine-containing imide anion are imide anions having a perfluoroalkyl group. More specific examples of the fluorine-containing imide anion are (CF3SO2)(CF3CO)N -Alternatively, it is an anion represented by the above general formula (a), (b), or (d), preferably (CF3SO2)2N - , (C2F5SO2)2N - (Perfluoroalkylsulfonyl)imides represented by general formula (a), more preferably (CF3SO2)2N - This is a bis(trifluoromethanesulfonyl)imide represented by . A preferred example of an inorganic cation salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0144] An example of an organic cationic salt is an organic cation-anionic salt. An example of a cation included in an organic cationic salt is an organic onium containing an organic group. An example of an onium included in an organic onium is nitrogen-containing onium, sulfur-containing onium, and phosphorus-containing onium, preferably nitrogen-containing onium and sulfur-containing onium. An example of nitrogen-containing onium is an ammonium cation, piperidinium cation, pyrrolidinium cation, pyridinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, pyrazolium cation, and pyrazolinium cation. An example of sulfur-containing onium is a sulfonium cation. An example of phosphorus-containing onium is a phosphonium cation. An example of an organic group included in an organic onium is an alkyl group, an alkoxyl group, and an alkenyl group. Specific examples of preferred organic oniums are tetraalkylammonium cations (e.g., tributylmethylammonium cation), alkylpiperidinium cations, and alkylpyrrolidinium cations.

[0145] The anions found in organic cationic salts are the same as those found in inorganic cationic salts. Preferred examples of organic cationic salts are 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI) and trimethylbutylammonium bis(trifluoromethanesulfonyl)imide.

[0146] The antistatic agent may be used in combination with an inorganic cationic salt and an organic cationic salt. The antistatic agent preferably contains an organic cationic salt.

[0147] The amount of antistatic agent in adhesive composition (B) is, for example, 0.5 parts by weight or more per 100 parts by weight of polymer (A), and may be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, or even 4 parts by weight or more. The upper limit of the amount is, for example, less than 30 parts by weight per 100 parts by weight of polymer (A), and may be 20 parts by weight or less, 15 parts by weight or less, 12 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, or even 6 parts by weight or less. By appropriately adjusting the amount of antistatic agent in adhesive composition (B), the durability of the adhesive sheet 5 can be further improved.

[0148] <3-1-c. Radical scavengers> The adhesive composition (B) may further contain a radical scavenger. Examples of radical scavengers include various antioxidants such as hindered phenols, hindered amines, phosphates, phenols, thioethers, and blends of these systems.

[0149] Examples of antioxidants include radical chain inhibitors and peroxide decomposers.

[0150] The antioxidant may be at least one selected from hindered phenols, hindered amines, and phosphates.

[0151] Hindered phenol antioxidants may have a structure in which a tert-butyl group is bonded to at least one carbon atom adjacent to the carbon atom on the aromatic ring to which the OH group of phenol is bonded. Examples of hindered phenol antioxidants include dibutylhydroxytoluene (BHT), as well as Irganox 1010, Irganox 1010FF, Irganox 1035, Irganox 1035FF, Irganox 1076, Irganox 1076FD, Irganox 1076DWJ, Irganox 1098, Irganox 1135, Irganox 1330, Irganox 1726, Irganox 1425WL, Irganox 1520L, Irganox 245, Irganox 245FF, Irganox 259, Irganox 3114, Irganox 565, and Irganox 295 (all trade names, manufactured by BASF).

[0152] Hindered amine antioxidants may have at least one hindered piperidine group in one molecule. Examples of hindered amine antioxidants are AdekaStab LA-63, AdekaStab LA-63P, AdekaStab LA-52, and AdekaStab LA-57 (all are trade names and manufactured by ADEKA).

[0153] Examples of phosphite antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, and phenyl diisodecyl phosphite; as well as ADEKA 2112, ADEKA 2112RG, ADEKA 1178, and ADEKA 3010 (all trade names, manufactured by ADEKA).

[0154] Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and polymeric phenolic antioxidants. Examples of monophenolic antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, and stearin-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. Examples of bisphenol antioxidants include 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane. Examples of high molecular weight phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0155] Examples of thioether-based antioxidants include AdekaStab AO-503 and AdekaStab AO-26 (both are trade names and manufactured by ADEKA).

[0156] The molecular weight of the radical scavenger (e.g., antioxidant) may be 1000 or less, 900 or less, 850 or less, 800 or less, 700 or less, 600 or less, 500 or less, 450 or less, or even 400 or less. The lower limit of the molecular weight is, for example, 100 or more. According to the inventors' studies, radical scavengers with molecular weights within the above range are particularly suitable for suppressing the amount of radicals generated in adhesive sheets formed from adhesive composition (B).

[0157] The radical scavenger (e.g., antioxidant) may be a liquid at 25°C.

[0158] The amount of radical scavenger in the adhesive composition (B) is, for example, 0.1 parts by weight or more per 100 parts by weight of polymer (A), and may be 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or even 0.5 parts by weight or more. The upper limit of the amount is, for example, 15 parts by weight or less per 100 parts by weight of polymer (A), and may be 10 parts by weight or less, 7 parts by weight or less, 5 parts by weight or less, less than 5 parts by weight, 4 parts by weight or less, 3 parts by weight or less, or even 2 parts by weight or less.

[0159] <3-1-d. Additives> The adhesive composition (B) may further contain materials other than those described above. Examples of such materials are additives. Examples of additives include crosslinking agents, silane coupling agents, colorants such as pigments and dyes, ultraviolet absorbers, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, rework improvers, softeners, polymerization inhibitors, rust inhibitors, inorganic fillers, organic fillers, powders, particles, and foils such as metal powders. The additives can be blended in total in an amount of, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 3 parts by weight or less, per 100 parts by weight of polymer (A).

[0160] Examples of crosslinking agents include organic crosslinking agents and polyfunctional metal chelates. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. Organic crosslinking agents and polyfunctional metal chelates can be used with either solvent-type or active energy ray-curing type adhesive compositions (B). When adhesive composition (B) is solvent-type, the crosslinking agent is preferably a peroxide crosslinking agent or an isocyanate crosslinking agent. A peroxide crosslinking agent and an isocyanate crosslinking agent may be used in combination. Adhesive composition (B) may contain an isocyanate crosslinking agent, may contain a peroxide crosslinking agent, or may contain both an isocyanate crosslinking agent and a peroxide crosslinking agent.

[0161] Examples of isocyanate crosslinking agents include aromatic isocyanate compounds such as tolylene diisocyanate, chlorphenyl diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, and polymethylene polyphenyl isocyanate; alicyclic isocyanate compounds such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and isophorone diisocyanate; and aliphatic isocyanate compounds such as butylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. The isocyanate crosslinking agent may be a compound obtained by adding the above isocyanate compound to a polyhydric alcohol compound such as trimethylolpropane (adduct); a compound obtained by adding the above isocyanate compound to a polyol such as polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and polyisoprene polyol; or a derivative of the above isocyanate compound such as isocyanurate. Specific examples of derivatives include trimethylolpropane / tolylene diisocyanate trimer adducts (e.g., Coronate L, manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate trimer adducts (e.g., Coronate HL, manufactured by Tosoh Corporation), and isocyanurate derivatives of hexamethylene diisocyanate (e.g., Coronate HX, manufactured by Tosoh Corporation).

[0162] If the adhesive composition (B) contains an isocyanate-based crosslinking agent, the amount of the agent is, for example, 0.1 to 10 parts by weight, 0.2 to 5 parts by weight, 0.25 to 3 parts by weight, 0.3 to 1 part by weight, or even 0.3 to 0.5 parts by weight, per 100 parts by weight of polymer (A).

[0163] Examples of peroxide-based crosslinking agents include di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, benzoyl peroxide, t-butylperoxyisobutyrate, and 1,1-di(t-hexylperoxy)cyclohexane. Benzoyl peroxide may also be used as a peroxide-based crosslinking agent due to its excellent crosslinking reaction efficiency.

[0164] If the adhesive composition (B) contains a peroxide-based crosslinking agent, the amount of the agent is, for example, 0.005 to 5 parts by weight per 100 parts by weight of polymer (A), and may also be 0.01 to 3 parts by weight, 0.05 to 2 parts by weight, 0.07 to 1 part by weight, 0.07 to 0.5 parts by weight, 0.07 to 0.3 parts by weight, or even 0.07 to 0.2 parts by weight.

[0165] Examples of silane coupling agents include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatetopropyltriethoxysilane.

[0166] If the adhesive composition (B) contains a silane coupling agent, the amount of the silane coupling agent is, for example, 5 parts by weight or less per 100 parts by weight of polymer (A), and may be 3 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, or even 0.05 parts by weight or less. The adhesive composition (B) does not have to contain a silane coupling agent.

[0167] The adhesive composition (B) can be, for example, an emulsion type, a solvent type (solution type), an active energy ray curing type (photocuring type), or a hot melt type. From the viewpoint of forming an adhesive sheet with excellent durability, the adhesive composition (B) may be a solvent type or an active energy ray curing type, or it may be a solvent type. The solvent type adhesive composition (B) does not need to contain a photocuring agent such as an ultraviolet curing agent.

[0168] The adhesive sheet 5 is formed from an adhesive composition (B). The adhesive sheet 5 includes, for example, a crosslinked (meth)acrylic polymer. The adhesive sheet 5 may be formed from the adhesive composition (B) by, for example, the following method.

[0169] The adhesive sheet 5 may be formed, for example, by applying the adhesive composition (B) to the substrate to form a coating film, and then drying the resulting coating film. This yields a second laminate consisting of the substrate and the adhesive sheet 5.

[0170] For example, a release film can be used as the base material. The adhesive sheet 5 formed on the release film can be transferred to, for example, an antistatic layer 1. Examples of base materials that can be used to form the adhesive sheet 5 are the same as those in the example of base material 12.

[0171] The release film can be used as a release film from the time the adhesive sheet 5 is transferred to the antistatic layer 1 until the adhesive sheet 5 is put into practical use. In this case, the process can be simplified.

[0172] Examples of materials that can be used to construct the release film include porous materials such as plastic film, paper, cloth, and nonwoven fabric, as well as appropriate thin sheets such as nets, foamed sheets, metal foils, and laminates thereof. However, plastic film is preferably used due to its excellent surface smoothness.

[0173] The plastic film is not particularly limited and includes, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, and the like.

[0174] The thickness of the release film is typically 5 to 200 μm, preferably about 5 to 100 μm. The release film may be treated with a release agent such as a silicone-based, fluorine-based, or long-chain alkyl-based release agent. The release film may also be treated with a release agent such as a fatty acid amide-based release agent or silica powder, or with an antifouling treatment, or with various antistatic treatments such as coating, mixing, or vapor deposition.

[0175] A solution containing the adhesive composition (B) (adhesive solution) may be applied to the substrate. The solid content concentration of the adhesive solution is, for example, 5 to 50% by weight, preferably 10 to 40% by weight. The adhesive solution may be prepared by appropriately adding the same solvent as the polymerization solvent or a different solvent to the adhesive composition (B), depending on the polymerization form of the (meth)acrylic polymer (A).

[0176] Various methods can be used to apply the adhesive composition (B) to the substrate. For example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and extrusion coating methods using a die coater are available. The amount of adhesive composition (B) applied can be appropriately adjusted according to the desired thickness of the adhesive sheet 5.

[0177] The coating hardens upon drying, forming the adhesive sheet 5. The drying temperature of the coating is, for example, 130°C or lower, preferably 125°C or lower, more preferably 120°C or lower, even more preferably 110°C or lower, and particularly preferably 100°C or lower. The drying temperature of the coating may be 60°C or higher, or 80°C or higher. A drying temperature of 60°C or higher can contribute to improving the cohesive strength of the adhesive sheet 5 by, for example, allowing the reaction of the isocyanate-based crosslinking agent to proceed smoothly. A drying temperature of 130°C or lower can contribute to improving the transparency of the adhesive sheet 5 by, for example, appropriately adjusting the reaction rate of the isocyanate-based crosslinking agent.

[0178] The drying time of the coated film can be appropriately adjusted according to the composition of the adhesive composition (B), preferably 30 to 300 seconds, more preferably 40 to 240 seconds, and particularly preferably 60 to 180 seconds.

[0179] The thickness of the adhesive sheet 5 is not particularly limited and may be 2 to 150 μm, 2 to 100 μm, or 5 to 50 μm. Appropriately adjusting the thickness of the adhesive sheet 5 can contribute to improving the adhesion between the adhesive sheet 5 and the antistatic layer 1. Furthermore, appropriately adjusting the thickness of the adhesive sheet 5 can contribute to suppressing the peeling of the adhesive sheet 5 from the adherend, such as glass and image display devices.

[0180] Figure 3 shows another example of an optical laminate that can be formed by the third manufacturing method. The optical laminate 3(3C) in Figure 3 has a structure in which an optical film 4, an antistatic layer 1, an adhesive sheet 5, and a release liner 6 are laminated in this order. After peeling off the release liner 6, the optical laminate 3C can be used by bonding it to an object such as an image display panel.

[0181] Examples of materials that can be used to construct the release liner 6 include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film; porous materials such as paper, cloth, and nonwoven fabric; nets, foamed sheets, metal foils, and suitable thin sheets such as laminates thereof. However, plastic films are preferably used due to their excellent surface smoothness.

[0182] The plastic film is not particularly limited as long as it is a film that can protect the adhesive sheet 5, and examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

[0183] The thickness of the release liner 6 is typically 5 to 200 μm, preferably about 5 to 100 μm. The release liner 6 may be subjected to various treatments as needed, such as mold release treatment, antifouling treatment, and antistatic treatment. For mold release treatment and antifouling treatment, various release agents such as silicone-based, fluorine-based, long-chain alkyl-based, and fatty acid amide-based agents, as well as particles such as silica powder, can be used. The antistatic treatment may be applied by coating, mixing, or vapor deposition. To improve the peelability of the adhesive sheet 5, it is particularly suitable to apply a release treatment to the surface of the release liner 6.

[0184] The release film used to form the adhesive sheet 5 may also be used as the release liner 6.

[0185] Optical laminates formed by the second or third manufacturing method can be distributed and stored, for example, as a wound body formed by winding a strip-shaped optical laminate, or as a single-wafer optical laminate. The optical laminate is suitable for use in image display devices, particularly automotive displays, used in environments where static electricity is particularly likely to occur. Examples of automotive displays include car navigation system panels, cluster panels, and mirror displays. A cluster panel is a panel that displays the vehicle's speed, engine RPM, etc. An image display device using an optical laminate formed by the second or third manufacturing method may be equipped with a touch sensing function. The touch sensing function may also be built into the image display panel of the image display device. The image display panel with a built-in touch sensing function may be a so-called in-cell type image display panel or an on-cell type image display panel.

[0186] The image display device using the optical laminate formed by the second or third manufacturing method may be an organic EL display or a liquid crystal display. However, the image display device is not limited to these examples. The image display device may be an electroluminescent (EL) display, a plasma display (PD), a field emission display (FED), etc. The image display device can be used for home appliance applications, automotive applications, public information display (PID) applications, etc., and may be an automotive display. [Examples]

[0187] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the examples shown below.

[0188] In this embodiment, an antistatic layer was formed on a polarizing film, and an optical laminate including the polarizing film and the antistatic layer was fabricated.

[0189] <Preparation of coating solution for forming an anti-static layer> (Coating liquid A1) A coating solution A1 with a solid content of 0.3% by weight was prepared by mixing 15 parts by weight of a solution containing single-walled carbon nanotubes (WNTs) and a binder resin (manufactured by Nagase ChemteX, product name: TS066-11-7) with 85 parts by weight of water. The binder resin was acrylic. The solid content ratio (by weight) of CNTs to binder resin in the prepared coating solution A1 was 1:99. The length of the CNTs was in the range of 5 μm to 200 μm, and the diameter was in the range of 2 nm to 8 nm.

[0190] (Coating liquid A2) A coating solution A2 with a solid content of 0.3% by weight was prepared by mixing 15 parts by weight of a solution containing single-walled carbon nanotubes (WNTs) and binder resin (manufactured by Nagase ChemteX, product name: TS066-11-7), 1.6 parts by weight of Sanyo Chemical Industries' Emulmin 240 (1% aqueous solution) as a polyether-based leveling agent, and 83.4 parts by weight of water. The solid content ratio (by weight) of CNTs, binder resin, and leveling agent in the prepared coating solution A2 was 1:94:5.

[0191] (Coating liquid A3) A solution containing single-walled carbon nanotubes and binder resin (manufactured by Nagase ChemteX Corporation, product name: TS066-11-7) was used as coating solution A3 (solid content concentration 2% by weight).

[0192] (Coating liquid A4) Coating solution A4 with a solid content of 1% by weight was prepared by mixing 50 parts by weight of a solution containing single-walled carbon nanotubes and binder resin (manufactured by Nagase ChemteX, product name: TS066-11-7) and 50 parts by weight of water.

[0193] (Coating liquid A5) A coating solution A5 with a solid content of 0.3% by weight was prepared by mixing 15 parts by weight of a solution containing single-walled carbon nanotubes (WNTs) and binder resin (manufactured by Nagase ChemteX, product name: TS066-11-7), 6.3 parts by weight of Sanyo Chemical Industries' Emulmin 240 (1% aqueous solution) as a polyether-based leveling agent, and 78.7 parts by weight of water. The solid content ratio (by weight) of CNTs, binder resin, and leveling agent in the prepared coating solution A5 was 1:79:20.

[0194] (Coating liquid A6) Coating solution A6 with a solid content of 0.1% by weight was prepared by mixing 5 parts by weight of a solution containing single-walled carbon nanotubes and binder resin (manufactured by Nagase ChemteX, product name: TS066-11-7) with 95 parts by weight of water.

[0195] (Coating liquid A7) A coating solution A7 with a solid content of 0.5% by weight was prepared by mixing 1.86 parts by weight of a solution containing multi-walled carbon nanotubes (manufactured by Mitsubishi Paper Mills, product name: YTM06), 1.4 parts by weight of Epocross WS700 (manufactured by Nippon Shokubai Co., Ltd.) as a binder resin containing oxazoline groups, and 96.7 parts by weight of water. The solid content ratio (by weight) of CNTs to binder resin in the prepared coating solution A7 was 2.5:97.5. The length of the CNTs was 0.8 μm and the diameter was 10 nm.

[0196] Table 1 summarizes the details for each coating solution.

[0197] [Table 1]

[0198] <Preparation of polarizing film> (Preparation of protective film A with a hard coat layer) A resin solution (DIC Corporation, trade name: Unidick 17-806, solids content: 80%) containing a UV-curable resin monomer or oligomer mainly composed of urethane acrylate dissolved in butyl acetate was prepared. Next, 5 parts by weight of a photopolymerization initiator (BASF Corporation, trade name: IRGACURE 907) and 0.1 parts by weight of a leveling agent (DIC Corporation, trade name: GRANDIC PC4100) were added to 100 parts by weight of the solids content of the resin solution. Next, cyclopentanone and propylene glycol monomethyl ether were added to the resin solution in a weight ratio of 45:55 to adjust the solids content of the resin solution to 36% by weight, thereby preparing a hard coat layer forming material. Next, the prepared forming material was applied to a transparent protective film containing triacetylcellulose (Konica Minolta Corporation TAC film, trade name "KC4UY", thickness 40 μm) to form a coating film. The thickness of the coating film was adjusted so that the hard coat layer obtained by the curing of the forming material was 7 μm thick. Next, the coating film was dried at 90°C for 1 minute, and then exposed to a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm². 2 The coating was irradiated with ultraviolet light. This hardened the coating, resulting in a protective film A (47 μm thick) with a hard coat layer (HC).

[0199] (Fabrication of polarizer A) A polyvinyl alcohol (PVA) film with an average degree of polymerization of 2400, a degree of saponification of 99.9 mol%, and a thickness of 45 μm was immersed in a swelling bath (water bath) at 20°C for 30 seconds to swell and stretched to 2.2 times its original size in the transport direction (swelling process). Next, the film was immersed in a dyeing bath at 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 per 100 parts by weight of water) for 30 seconds, adjusting the concentration so that the final iodine concentration of the polarizer obtained was 3.1% by weight, and stretched to 3.3 times its original size in the transport direction relative to the original PVA film (PVA film that had not been stretched at all in the transport direction) (dyeing process). Rollers with different peripheral speed ratios were used for stretching. Next, the stained PVA film was immersed for 28 seconds in a 40°C crosslinking bath (an aqueous solution with boric acid concentration of 3.5 wt%, potassium iodide concentration of 3.0 wt%, and zinc sulfate concentration of 3.6 wt%) to stretch it to 3.6 times its original size in the transport direction (crosslinking step). Next, the crosslinked PVA film was immersed for 60 seconds in a 64°C stretching bath (an aqueous solution with boric acid concentration of 4.5 wt%, potassium iodide concentration of 5.0 wt%, and zinc sulfate concentration of 5.0 wt%) to stretch it to 6.0 times its original size in the transport direction (stretching step). Next, it was immersed for 10 seconds in a 27°C washing bath (an aqueous solution with potassium iodide concentration of 2.3 wt%) (washing step), and the washed PVA film was dried at 40°C for 30 seconds to obtain a polarizer A with a thickness of 18 μm.

[0200] (Preparation of phase difference film A) In an autoclave equipped with a stirrer, condenser, nitrogen inlet tube, and thermometer, 48 parts by weight of hydroxypropyl methylcellulose (Shin-Etsu Chemical, Metroze 60SH-50), 15601 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate, 240 parts by weight of 3-ethyl-3-oxetanylmethyl acrylate, and 45 parts by weight of t-butyl peroxypivalate, a polymerization initiator, were placed. After 1 hour of nitrogen bubbling, the mixture was maintained at 49°C for 24 hours with stirring to allow radical suspension polymerization to proceed. Next, after cooling to room temperature, the particles of the fumarate ester resin produced by polymerization were centrifuged. The obtained particles were washed twice with distilled water and twice with methanol, and then dried under reduced pressure. Next, the particles were dissolved in a toluene / methyl ethyl ketone mixed solution (toluene / methyl ethyl ketone 50% by weight / 50% by weight) to obtain a 20% by weight solution. Furthermore, a dope was prepared by adding 5 parts by weight of tributyl trimellitate as a plasticizer to 100 parts by weight of fumarate ester resin. Next, the prepared dope was applied to the support film to a dry film thickness of 6.3 μm and dried at 140°C. A biaxially oriented polyester (polyethylene terephthalate / polyethylene isophthalate copolymer) film (75 μm thick, heat-treated) was used as the support. Next, the laminate obtained in this way was uniaxially stretched at a temperature of 140°C. The support film was peeled off the stretched laminate to obtain a phase difference film A (6 μm thick, Re(550) is 35 nm).

[0201] (Preparation of polarizing film A) A protective film A with HC was laminated to one main surface of polarizer A, and a phase difference film B (ZT12, cycloolefin film with a thickness of 17 μm, manufactured by Nippon Zeon Co., Ltd.) was laminated to the other main surface using a roll laminating machine. Lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing acetoacetyl group-containing PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetoacetylation 5 mol%) and methylolmelamine in a weight ratio of 3:1. Next, the entire structure was heated and dried in an oven, and then a photocurable adhesive composition was coated to a thickness of 1 μm on the phase difference film B side of the resulting laminated film. An MCD coater (manufactured by Fuji Machinery Co., Ltd.) was used for coating. The composition of the adhesive composition is as follows: • 20 parts by weight of unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (Daicel, Praxel FA1DDM) • Acryloylmorpholin (manufactured by Kojin) 20 parts by weight • Diethylacrylamide (manufactured by KJ Chemicals, DEAA) 3 parts by weight • Lauryl acrylate (manufactured by Kyoeisha Chemical, "Light Acrylate LA") 6.7 parts by weight Isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., ISTA) 27 parts by weight 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical, Light Acrylate 1,9ND-A) 10 parts by weight 13.3 parts by weight of a 34 / 66 molar ratio copolymer oligomer of butyl acrylate and methacrylate (manufactured by Toagosei, ARUFON UP-1190, molecular weight 1700) • As a photoinitiator, 3 parts by weight of Omnirad 907 (manufactured by IGM Resins BV) • As a photoinitiator, 3 parts by weight of diethylthioxanthone (manufactured by Nippon Kayaku, KAYACURE DETX-S)

[0202] Next, the phase difference film A prepared above was bonded to the coated adhesive composition using a roll laminating machine. The bonding was performed at 30°C. Then, visible light from a gallium-filled metal halide lamp was used as the active energy ray from the side of the phase difference film A (irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V-bulb, peak illuminance: 1600 mW / cm²). 2 Integrated irradiation dose of 1000 / mJ / cm² at wavelengths of 380-440nm 2 The adhesive composition was cured by irradiation with ) . Then, it was heat-dried at 70°C for 3 minutes to obtain polarizing film A.

[0203] <Formation of an anti-static layer and fabrication of an optical laminate using the same> An optical laminate having a laminated structure of an antistatic layer / polarizing film was fabricated by applying one of the above-prepared coating solutions to the exposed surface of the transparent protective film of the polarizing film A prepared above using a wire bar, and drying the formed coating film in a drying oven. Table 2 below shows the manufacturing conditions of the antistatic layer in the fabricated optical laminate and the thickness of the formed antistatic layer.

[0204] [Table 2]

[0205] [evaluation] The following evaluations were performed on the formed antistatic layer.

[0206] (In-plane variation of surface resistivity) The in-plane variation of surface resistivity was evaluated as follows: Surface resistivity was measured at each of six measurement points set on the exposed surface of the formed antistatic layer. The six measurement points were set randomly without overlap. Surface resistivity at each measurement point was measured using a Highresta MCP-HT800 (manufactured by Mitsubishi Chemical Analytec Co., Ltd.) in accordance with the method specified in JIS K6911:1995, under the conditions of applied voltage of 10V and application time of 10 seconds. The measurements were also performed in an environment of 25°C. Of the six measured values, the difference between the common logarithm of the maximum value and the common logarithm of the minimum value was calculated, and the in-plane variation of surface resistivity was evaluated according to the following evaluation criteria. A: Difference is 0.3 or less B: Difference greater than 0.3 and less than 1 C: Difference is 1 or greater but less than 1.5 D: Difference is 1.5 or greater

[0207] (Resistivity reliability) To assess the resistivity reliability of the antistatic layer, the change in surface resistivity before and after the DIN test was evaluated. Specifically, the surface resistivity A (before the DIN test) and surface resistivity B (after the DIN test) of the exposed surface of the antistatic layer were measured at each point in time before and after the DIN test, and the value of logB-logA was calculated. The closer the value of logB-logA is to zero, the higher the resistivity reliability can be judged. The DIN test was conducted in accordance with the weather resistance test (test conditions: Z-IN1) specified in DIN75220. Surface resistivity A and B were measured using a HighResta MCP-HT800 (manufactured by Mitsubishi Chemical Analytec Co., Ltd.) in accordance with the method specified in JIS K6911:1995, with an applied voltage of 10V, an application time of 10 seconds, and an ambient temperature of 25°C.

[0208] Separately from the above, the following evaluations were performed on the fabricated optical laminates containing polarizing films.

[0209] (Degree of curl) The degree of curling of the optical laminate was determined by cutting the fabricated optical laminate into a rectangle measuring 330 mm x 230 mm, placing it on a horizontal surface with the convex side facing down, and measuring the maximum amount of lift from the horizontal surface once it was stable. The amount of lift was measured perpendicular to the horizontal surface.

[0210] The evaluation results are shown in Table 3 below.

[0211] [Table 3]

[0212] As shown in Table 3, compared to the comparative example, the example was able to suppress in-plane variations in surface resistivity of the antistatic layer and improve resistivity reliability. [Industrial applicability]

[0213] The antistatic layer produced by the manufacturing method of the present invention is suitable for use in image display devices used in harsh environments such as in automobiles. [Explanation of symbols]

[0214] 1. Antistatic layer 3,3A,3B,3C optical laminate 4 Optical film 5 Adhesive sheets 6. Peel-off liner

Claims

1. A method for manufacturing an antistatic layer used in an optical laminate, A coating solution containing a conductive material, a binder resin, and a solvent is applied to the surface of a substrate to form a coating film. The process includes drying the coating film under the following conditions (1) and (2) to remove the solvent and form the antistatic layer, The conductive material is a single-walled carbon nanotube with a length of 3 μm or more and less than 300 μm. A method for manufacturing an antistatic layer. Condition (1): The drying temperature T of the coating film is 50°C or higher. Condition (2): The time Z from the start of applying the coating liquid to the surface of the substrate to the start of drying of the coating film is 0.01 seconds or more and 50 seconds or less.

2. The manufacturing method according to claim 1, wherein the coated film is dried in a manner that satisfies the following condition (3) in addition to the conditions (1) and (2) above. Condition (3): The drying time H of the coating film is 10 seconds or more and 150 seconds or less.

3. The manufacturing method according to claim 1, wherein the drying temperature T is 130°C or less.

4. The manufacturing method according to claim 1, wherein the coating liquid substantially does not contain a leveling agent, or contains a leveling agent in an amount of 8 parts by weight or less, based on the amount of solids contained in the coating liquid.

5. The coating liquid either substantially does not contain a leveling agent, or contains a leveling agent in an amount of 8 parts by weight or less, based on the amount of solids contained in the coating liquid per 100 parts by weight. The manufacturing method according to claim 1, wherein the coated film is dried so that the time Z satisfies the condition of 15 seconds or less.

6. The manufacturing method according to claim 1, wherein the coating film having a thickness of 1 μm or more and 12 μm or less is formed on the surface of the substrate.

7. The manufacturing method according to claim 1, wherein the substrate is an optical film.

8. The manufacturing method according to claim 1, wherein the substrate includes a polarizing film.

9. The manufacturing method according to claim 1, wherein the formation of the coating film and the drying of the formed coating film are carried out while conveying the strip-shaped substrate.

10. The manufacturing method according to claim 1, wherein the antistatic layer having a thickness of 5 nm or more and 200 nm or less is formed.

11. 1.0 x 10 9 The manufacturing method according to claim 1, wherein the antistatic layer having a surface resistivity of Ω / □ or less is formed.

12. The manufacturing method according to claim 1, wherein the antistatic layer satisfying the following formula (I) is formed. However, in formula (I), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test condition: Z-IN1) specified in German industrial standard DIN 75220, respectively. -2≦logB-logA≦2 (I)

13. A method for manufacturing an optical laminate comprising an optical film and an antistatic layer in this order, The method includes forming the antistatic layer by the manufacturing method described in any one of claims 1 to 12. A method for manufacturing optical laminates.

14. The substrate is an optical film, The manufacturing method according to claim 13, wherein the antistatic layer is formed on the optical film.

15. The manufacturing method according to claim 13, wherein the optical film includes a polarizing film.

16. A method for manufacturing an optical laminate comprising an optical film, an antistatic layer, and an adhesive sheet in this order, The method includes forming the antistatic layer by the manufacturing method described in any one of claims 1 to 12. A method for manufacturing optical laminates.

17. The substrate is an optical film, The manufacturing method according to claim 16, wherein the antistatic layer is formed on the optical film.

18. The manufacturing method according to claim 16, wherein the optical film includes a polarizing film.

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