TW202601246A - Optical laminates, image display panels, and image display devices - Google Patents

Abstract

The optical laminate provided by this invention comprises an adhesive sheet, an antistatic layer, and an optical film. The antistatic layer contains conductive particles. The antistatic layer satisfies the following equation (1). In equation (1), D is the product of the particle area ratio P (%) and the total current value Q (nA) of the antistatic layer as evaluated by atomic force microscopy (P×0.01)×Q. E is the product of the particle area ratio P (%) and the total current value (nA) of the antistatic layer as evaluated by atomic force microscopy after undergoing the weathering resistance test (test condition: Z-IN1) specified in German industrial standard DIN75220 (test condition: Z-IN1) (P×0.01)×Q. This optical laminate is suitable for use in image display devices in harsh environments such as automotive applications. 0.01≦E/D≦300　　　　(1)

Description

Optical laminates, image display panels, and image display devices

This invention relates to optical laminates, image display panels, and image display devices.

Image display devices, represented by liquid crystal displays (LCDs) and electroluminescent (EL) displays (such as organic EL displays and inorganic EL displays), are widespread. These image display devices, for example, have image display units such as liquid crystal cells and EL light-emitting elements, and a laminated structure comprising an optical laminate containing a polarizing film and an adhesive sheet. The adhesive sheet is mainly used for bonding between the thin films contained in the optical laminate or for bonding the image display unit to the optical laminate.

Static electricity can sometimes be generated during the manufacturing or use of image display devices. During manufacturing, static electricity is easily generated when the optical multilayer is bonded to the image display unit using an adhesive sheet. During use, static electricity is easily generated when the user touches the image display device. If the image display device becomes charged due to static electricity, display problems may occur. Patent 1 discloses an optical multilayer having a polarizing film and a conductive layer containing a conductive polymer. [Prior Art Documents] [Patent Documents]

Patent Document 1: Japanese Patent Publication No. 2015-509615

Problem to be Solved by the Invention: Based on the inventors' review, the optical layer of Patent 1 has room for further improvement due to the different environments in which image display devices are used. The purpose of this invention is to provide an optical layer suitable for use in image display devices in harsh environments such as automotive applications.

Means for solving the problem: The inventors discovered that display defects are prone to occur in applications such as vehicle-mounted applications exposed to harsh environments, and based on this, the inventors completed the present invention.

[1] The optical laminate of the present invention comprises an adhesive sheet, an antistatic layer and an optical thin film; and the aforementioned antistatic layer contains conductive particles; and the aforementioned antistatic layer satisfies the following formula (1); 0.01≦E/D≦300 (1) However, D in the aforementioned formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the aforementioned antistatic layer as evaluated by atomic force microscopy (P×0.01)×Q; E in the aforementioned formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the antistatic layer as evaluated by atomic force microscopy after undergoing the weather resistance test (test condition: Z-IN1) specified by German industrial standard DIN75220. (P×0.01)×Q. [2] In the optical laminate as described in [1] above, the thickness of the aforementioned antistatic layer can also be 5 nm or more and 100 nm or less. [3] In the optical laminate as described in [1] or [2] above, the aforementioned conductive particles can also include carbon nanotubes. [4] In the optical laminate as described in [3] above, the length of the aforementioned carbon nanotubes can also be 3 µm or more and 300 µm or less, and the diameter can also be 10 nm or less. [5] In any of the optical laminates described in [1] to [4] above, the aforementioned antistatic layer may also contain a binder resin. [6] In any of the optical laminates described in [1] to [5] above, the aforementioned antistatic layer may also contain a binder resin with a glass transition temperature of 0°C or higher. [7] In the optical laminates described in [5] or [6] above, the proportion of the aforementioned binder resin with a glass transition temperature of 0°C or higher in all the aforementioned binder resins contained in the aforementioned antistatic layer may also be 50% by weight or more. [8] In any of the optical laminates described in [1] to [7] above, the aforementioned antistatic layer may also substantially not contain a leveling agent. [9] In any of the optical laminates described in [1] to [8] above, the aforementioned adhesive sheet may also be formed from an adhesive composition containing polymer (A). [10] In the optical laminate described in [9] above, the aforementioned polymer (A) may also be a (meth)acrylic polymer. [11] In the optical laminate described in [9] or [10] above, the aforementioned adhesive composition may also contain the aforementioned polymer (A) having a polyether structure as a main component. [12] In the optical laminate described in any of [9] to [11] above, the aforementioned polymer (A) may also have structural units derived from the monomer shown in the following formula (2); [Formula 1] In formula (2), ^R1 is a hydrogen atom or a methyl group, ^R2 is an alkyl group that may be linear or branched, and n is an integer from 1 to 15. [13] In any of the optical laminates described in [9] to [12] above, the aforementioned adhesive composition may further include an antistatic agent. [14] In the optical laminate described in [13] above, in the aforementioned adhesive composition, the amount of the aforementioned antistatic agent may be less than 30 parts by weight relative to 100 parts by weight of the aforementioned polymer (A). [15] In any of the optical laminates described in [1] to [14] above, the loss of total light transmittance caused by the aforementioned antistatic layer may be less than 1.0%. [16] In any of the optical laminates described in [1] to [15] above, the aforementioned optical thin film may also include a polarizing thin film. [17] In the optical laminate described in [16] above, the bending diameter of the aforementioned polarizing thin film, as evaluated by the following test method, may also be 3 mm or more; <Test Method> Prepare a test piece, wherein the test piece is made with the absorption axis of the polarizing element as the long side direction, and the aforementioned optical thin film is processed into a rectangle with a width of 10 mm and a length of 50 mm; then, fix one end of the aforementioned test piece in the long side direction to the surface of the evaluation sheet; then, heat the whole body at 105°C for 12 hours, so that the aforementioned test piece is bent from the other end of the aforementioned test piece in the long side direction; determine the diameter of the cylindrical portion formed by the bending of the aforementioned test piece as the aforementioned bending diameter. [18] In the optical laminate as described in [16] or [17] above, the absolute value of the bending moment M of the aforementioned polarizing film when heated may also be less than 1× ^10⁹ . [19] In the optical laminate as described in any of [1] to [18] above, the aforementioned conductive particles may also include carbon nanotubes; and the aforementioned antistatic layer may also include a binder resin with a glass transition temperature of 0°C or higher. [20] In the optical laminate as described in [19] above, the length of the aforementioned carbon nanotubes may also be 3µm or more and 300µm or less, and the diameter may also be 10nm or less. [21] The image display panel of the present invention has an optical laminate as described in any of [1] to [20] above. [22] The image display device of the present invention has an image display panel as described above [21].

The invention provides an optical layer suitable for use in image display devices in harsh environments such as automotive applications.

The present invention will now be described in detail. However, the present invention is not limited to the embodiments shown below. The present invention may be modified and implemented in any way without departing from the spirit of the present invention.

[Regarding terminology] In this manual, when "weight" is used, it can be replaced with "mass," the SI unit commonly used to express weight. The reverse is also true.

In this manual, when "(meth)acrylic acid" is mentioned, it means "acrylic acid and/or methacrylic acid"; when "(meth)acrylate" is mentioned, it means "acrylate and/or methacrylate"; when "(meth)acryl" is mentioned, it means "acryl and/or methacryl"; when "(meth)acrylaldehyde" is mentioned, it means "acrylaldehyde and/or methacrolein".

≪≪1. Optical Multilayer Assembly≫≫ FIG. 1 shows an example of an optical multilayer assembly according to an embodiment of the present invention. The optical multilayer assembly 10 (10A) of FIG. 1 includes an adhesive sheet 1, an antistatic layer 2, and an optical thin film 3. The optical multilayer assembly 10A has a structure in which the adhesive sheet 1, the antistatic layer 2, and the optical thin film 3 are sequentially laminated. However, the lamination order of the layers in the optical multilayer assembly 10 is not limited to the example of FIG. 1. The optical multilayer assembly 10 can be bonded to an object such as an image display panel through the adhesive sheet 1.

In Figure 1, the adhesive sheet 1 is attached to the antistatic layer 2. However, other thin films and/or layers may also be disposed between the adhesive sheet 1 and the antistatic layer 2. Furthermore, when viewed in the lamination direction, the adhesive sheet 1 in Figure 1 is formed entirely on one main surface of the antistatic layer 2. However, when viewed in the lamination direction, the adhesive sheet 1 may also be formed on a portion of one main surface of the antistatic layer 2. In this specification, "main surface" refers to the surface with the largest area in the thin film or layer.

The optical thin film 3 in Figure 1 is in contact with the antistatic layer 2. However, other thin films and/or layers may also be disposed between the optical thin film 3 and the antistatic layer 2. Furthermore, when viewed in the lamination direction, the optical thin film 3 in Figure 1 is formed on the entire other main surface of the antistatic layer 2. However, when viewed in the lamination direction, the optical thin film 3 may also be formed on a portion of the other main surface of the antistatic layer 2.

The antistatic layer 2 in Figure 1 is sandwiched between the adhesive sheet 1 and the optical film 3.

≪1-1. Antistatic Layer≫ The antistatic layer 2 contains conductive particles (conductive fillers). The antistatic layer 2 satisfies the following formula (1). However, D in formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the antistatic layer 2 as evaluated by atomic force microscopy (P×0.01)×Q. Also, E in formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the antistatic layer 2 as evaluated by atomic force microscopy (hereinafter referred to as "AFM") after undergoing the weathering test (test condition: Z-IN1) specified in German industrial standard DIN75220. (P×0.01)×Q. 0.01≦E/D≦300　　　　(1)

The antistatic layer 2 can help suppress display defects caused by static electricity. However, according to the inventors' research, the state of the conductive particles in the antistatic layer 2, which contains conductive particles, may change significantly when exposed to harsh environments such as automotive applications. Although the antistatic layer 2 can be designed to withstand harsh environments, there are limits to its performance if the changes in state are significant. For example, the electrical properties of the antistatic layer 2 may be insufficient at both the time points before and after exposure to harsh environments. The weathering resistance test specified in DIN 75220 (hereinafter referred to as the "DIN test") is a weathering resistance test that takes into account the aforementioned harsh environments. In the case of antistatic layer 2, the changes in the state of conductive particles in antistatic layer 2 before and after the DIN test are limited.

The test condition Z-IN1 in the DIN test is an indoor test (Zone 1), which 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, the following operation constitutes one cycle and is repeated within 15 days: (1) irradiation with ultraviolet light for 8 hours in an atmosphere with a temperature of 80°C and a relative humidity of 20%; (2) placement in an atmosphere with a temperature of 10°C and a relative humidity of 60% (without ultraviolet light) for 3.5 hours; (3) irradiation with ultraviolet light for 8 hours in an atmosphere with a temperature of 80°C and a relative humidity of 20%; and (4) placement in an atmosphere with a temperature of 10°C and a relative humidity of 60% (without ultraviolet light) for 3.5 hours. However, between (4) of one cycle and (1) of the next cycle, the operation of placing at room temperature (23°C) for 1 hour is performed. In the humid climate cycle, the following operations constitute one cycle and are repeated over 10 days: (1) placing in a gas environment at -10°C (without UV radiation) for 5 hours; (2) irradiating with UV radiation in a gas environment at 80°C and 50% relative humidity for 12 hours; and (3) placing in a gas environment at -10°C (without UV radiation) for 6 hours. However, between (3) of one cycle and (1) of the next cycle, the operation of placing at room temperature for 1 hour is performed. The term "interior" (Zone 1) refers to the location of automotive parts and materials within the vehicle, specifically those exposed to higher temperatures but receiving less sunlight than the exterior. The illuminance of metal halogen lamps used for ultraviolet irradiation is set at 830 W/ ^m² .

Furthermore, based on our research, we believe that representing the state of conductive particles by the product of the particle area ratio and the total current value in the antistatic layer 2 is suitable for demonstrating the charge suppression capability of the antistatic layer 2. To improve charge suppression capability, we hypothesize that the following configuration is suitable: while ensuring the electrostatic pathway is maintained through appropriate contact between conductive particles, from a broader perspective, the pathways formed by the conductive particles in the antistatic layer 2 will spread throughout the layer with good dispersion. The particle area ratio and the total current value may each reflect the degree of dispersion of the conductive particles in the antistatic layer 2 and the degree of contact between the conductive particles contained in the antistatic layer 2.

The particle area ratio and total current value are characteristics of the antistatic layer 2 evaluated by AFM. The evaluation using AFM can be performed using the following procedures and test conditions. [Preparation of Test Specimen] First, the antistatic layer 2 of the evaluation object is cut into a square area with a side length of 20µm that can contain the test area, and then fixed to the surface of an AFM disk of appropriate size to make a test specimen. The AFM disk should preferably be selected with the fixing surface of the antistatic layer 2 already gold-coated. In addition, as long as the above-mentioned test area with the antistatic layer 2 is exposed when fixed to the AFM disk, other layers or sheets can also be bonded to the cut antistatic layer 2 and the fixed antistatic layer 2. The AFM disc can be fixed using conductive tape, such as adhesive tape containing carbon particles in the adhesive. One example of such adhesive tape is "Conductive Carbon Double-Sided Tape" manufactured by Nisshin EM Co., Ltd. From the perspective of suppressing the tape's own charge and preventing its influence on the measurement, the use of conductive tape is recommended. The antistatic layer 2 is fixed to the AFM disc 72, for example, by attaching it to the disc using a conductive tape 74 with double-sided adhesive properties (see Figures 2A, 2B, and 2C). Figure 2A is a top view schematically showing an example of a test sample 71 with the antistatic layer 2 fixed thereon. Figure 2B is a cross-sectional view showing section 2B-2B of the test sample 71 in Figure 2A. Figure 2C is a cross-sectional view of the test sample 71 shown in Figure 2A, section 2C-2C. In the examples shown in Figures 2A-2C, three antistatic layers 2 (73A, 73B, 73C) are fixed to the AFM disk 72. Multiple antistatic layers 2 can be fixed as described, and at least one antistatic layer 2 can also be used as a reference. The reference can be used, for example, to confirm the reproducibility of the test data. Next, to ensure electrical conductivity between the fixed antistatic layers 2 and the AFM disk 72, a metal paste 75, such as silver (Ag) paste, is applied. The application of the metal paste 75 ensures electrical conductivity between the AFM disk 72 and the antistatic layer 2 of the evaluation object, and is carried out in a manner that does not obstruct the AFM's measurement of the measurement area of the antistatic layer 2. In the examples of Figures 2A-2C, the metal paste 75 is applied in the following manner: covering both ends of the long side of the antistatic layers 73A, 73B, and 73C respectively and connecting them to the AFM disk 72, while exposing the measurement areas in each of the antistatic layers 73A, 73B, and 73C. [Measurement and Measurement Conditions] The prepared test sample was installed in an AFM measurement apparatus, such as the Hitachi High-Tech Co. AFM5300E, which is designed for electrical measurements under high vacuum. Next, the gas environment in which the test sample was placed was set to a high vacuum with a pressure less than ^10⁻⁴ Pa. After the high vacuum stabilized, AFM measurement was performed on the measurement area under the following measurement conditions. However, the AFM measurement was performed with a potential difference applied between the front end of the cantilever and the test sample, and the measurement area was distributed in two dimensions by the current flowing through the cantilever. The pixel size in the two-dimensional distribution image was set to 78 nm square. By using AFM measurement with an applied potential difference, the parts of the measurement area where current flows easily and those that do not can be identified. We believe that in the antistatic layer 2, the current mainly flows in the areas where conductive particles are present. A current threshold can be set for each pixel constituting the 2D distribution image. The distribution image is then binarized into a first pixel with current flowing above the threshold and a second pixel with current flowing only below the threshold. The ratio of the total area occupied by all first pixels in the measurement area ( ^400µm² ) is calculated and identified as the particle area ratio P (unit: %). Furthermore, the sum of the current values of all pixels in the 2D distribution image can be identified as the total current value Q (unit: nA). However, pixels with measured negative current values are considered measurement noise and therefore their current values are not added to the sum. The data processing for the AFM measurement can also be performed using the data analysis software included with the AFM measurement device. (Measurement Conditions) Measurement Mode: AFM Mode Cantilever: Electrical Measurement Applicant (e.g., Hitachi High-Tech SI-DF40-R with rhodium coating on the back and front) Measurement Area: 20µm × 20µm square Measurement Temperature: Room temperature (25±5℃) Applied Potential Difference: 0.3V IV Amp: Nano Amp Current Threshold: 0.1nA Number of Pixels in the 2D Distribution Image (Number of Measurement Points in the Measurement Area): 256 × 256 points (Total 65536 points)

The E/D in formula (1) can also be less than 275, less than 250, less than 225, less than 200, less than 180, less than 160, less than 150, less than 130, less than 110, less than 100, less than 90, less than 85, less than 80, less than 75, less than 70, less than 65, less than 60, less than 55, less than 50, less than 45, less than 40, less than 35, less than 30, less than 25, less than 20, less than 18, less than 16, less than 15, less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, and even less than 4.5. The lower limit of E/D can also be above 0.05, above 0.1, above 0.5, above 1, above 1, above 1.1, above 1.2, above 1.3, above 1.4, above 1.5, above 1.6, above 1.7, above 1.8, above 1.9, or even above 2.

The E/D ratio in equation (1) may vary depending on the composition and formation method of the antistatic layer 2. Examples of composition include the type and content of conductive particles, and the type, content, and characteristics of materials other than conductive particles. Examples of materials other than conductive particles include binder resin and leveling agent. Examples of formation methods include the composition and formation conditions of the coating liquid used to form the antistatic layer 2. Examples of the composition of the coating liquid include the type of solvent. Examples of formation conditions include the drying temperature of the coating liquid.

The D of antistatic layer 2 (the product of the particle area ratio P (%) of antistatic layer 2 before undergoing the DIN test and the total current value Q (nA) (P×0.01)×Q) can be, for example, 1.0× ^10³ nA or higher, or 1.5× ^10³ nA or higher, 2.0× ^10³ nA or higher, 2.5× ^10³ nA or higher, 3.0× ^10³ nA or higher, 3.5× ^10³ nA or higher, 4.0× ^10³ nA or higher, 4.5× ^10³ nA or higher, 5.0× ^10³ nA or higher, 5.5× ^10³ nA or higher, 6.0× ^10³ nA or higher, 6.5× ^10³ nA or higher, 7.0×10³ nA or higher, 7.5× ^10³ nA or higher, 8.0× ^10³ nA or higher, etc. ³ nA or higher, 8.5×10 ³ nA or higher, 9.0×10 ³ nA or higher, 9.5×10 ³ nA or higher, 1.0×10 ⁴ nA or higher, 1.1×10 ⁴ nA or higher, 1.2×10 ⁴ nA or higher, 1.3×10 ⁴ nA or higher, 1.4×10 ⁴ nA or higher, 1.5×10 ⁴ nA or higher, 1.6×10 ⁴ nA or higher, 1.7×10 ⁴ nA or higher, 1.8×10 ⁴ nA or higher, 1.9×10 ⁴ nA or higher, and even 2.0×10 ⁴ nA or higher. The upper limit of D can be, for example, below 1.0 × ^10⁵ nA, or below 9.0 × ^10⁴ nA, below 8.0 × ^10⁴ nA, below 7.0 × ^10⁴ nA, below 6.0 × ^10⁴ nA, below 5.0 × ^10⁴ nA, below 4.0 × ^10⁴ nA, below 3.0 × ^10⁴ nA, or even below 2.5 × ^10⁴ nA.

The E value of the antistatic layer 2 (the product of the particle area ratio P (%) of the antistatic layer 2 after undergoing the DIN test and the total current value Q (nA) (P×0.01)×Q) can be, for example, 1.0× ^10³ nA or higher, or 5.0× ^10³ nA or higher, 7.0× ^10³ nA or higher, 9.0× ^10³ nA or higher, 1.0× ^10⁴ nA or higher, 2.0× ^10⁴ nA or higher, 3.0× ^10⁴ nA or higher, 4.0× ^10⁴ nA or higher, 5.0× ^10⁴ nA or higher, 5.5×10⁴ nA or higher, 6.0× ^10⁴ nA or higher, 6.5× ^10⁴ nA or higher, 7.0× ^10⁴ nA or higher, 7.5× ^10⁴ nA or higher, 7.5×10⁴ nA or higher ^. The upper limit of E is, for example, 5.0 × ^10⁵ nA or less, or 4.0 × ^10⁵ nA or less, 3.0 × ^10⁵ nA or less, 2.0 × ^10⁵ nA or less, 1.0 × ^{10⁵ nA} or less, or even 9.0 × ^10⁴ nA or less.

The antistatic layer 2 can be a layer in which the product of particle area fraction and total current value is maintained or increased in the DIN test. In other words, the relationship between E and D can be expressed by the formula: E≧D, or by the formula: E＞D.

The antistatic layer 2 contains conductive particles. These conductive particles can also be carbon particles. Examples of carbon particles include carbon blacks such as acetylene black and Ketjen black, natural graphite, artificial graphite, and carbon nanotubes (CNTs). Based on the inventors' research, carbon particles, especially CNTs, are preferable as conductive particles in the antistatic layer 2. In other words, the antistatic layer 2 can contain either carbon particles or CNTs. We believe carbon particles, especially CNTs, are ideal because they are less prone to degradation under the aforementioned harsh environments compared to conductive polymers or composites of conductive polymers and dopants; typically, they are less prone to degradation due to oxidation. If the conductive material contained in the antistatic layer 2 deteriorates, the antistatic capability of the antistatic layer 2 will generally decrease. Furthermore, the fact that CNTs are particularly desirable among carbon particles may be because the high degree of anisotropy in the shape of CNTs helps to suppress excessive aggregation or orientation under high temperature and humidity. The antistatic layer 2 may also contain two or more types of conductive particles. Additionally, the antistatic layer 2 may also contain conductive particles (e.g., CNTs) and other conductive materials (e.g., conductive polymers). Examples of other conductive materials include conductive polymers, complexes of conductive polymers and dopants, ionic surfactants, and ionic compounds.

There are no limitations on the type of CNTs. CNTs can be manufactured using various methods such as arc discharge, laser evaporation, and chemical vapor deposition (CVD). CNTs can be any of the following: monolayer CNTs, binary CNTs, and multilayer CNTs, or a mixture of two or more of these. From the viewpoint of excellent conductivity, monolayer CNTs are particularly suitable.

The length of CNTs can be, for example, 1~2000µm, or 1~1000µm, or even 1~500µm. The diameter (outer diameter) of CNTs can be, for example, 0.1~50nm, or even 0.2~40nm, 0.25~30nm, 0.3~20nm, 0.4~15nm, or even 0.5~10nm. From the perspective of dispersion in the antistatic layer 2, the length of CNTs can be less than 300µm, or less than 300µm, 275µm, 250µm, 225µm, 200µm, 175µm, 150µm, 125µm, 100µm, 90µm, 80µm, 70µm, 60µm, 50µm, 40µm, 30µm, 25µm, 20µm, 15µm, 10µm, and even less than 5µm. Furthermore, from the perspective of dispersion in the antistatic layer 2, the length of CNTs can be more than 3µm and less than 300µm, and the diameter can be less than 10nm. The length of CNTs can be assessed by observation using AFM or scanning electron microscopy (SEM). The diameter of CNTs can be determined according to the specifications of ISO/TS10868:2017.

The CNT content in the antistatic layer 2 is, for example, 0.01~50.0 mg/ ^m² , or 0.1~10.0 mg/ ^m² . The percentage of CNTs in the total solid content of the antistatic layer 2 is, for example, 0.01~90% by weight, or 0.01~50% by weight, 0.01~30% by weight, 0.05~25% by weight, 0.1~20% by weight, 0.15~15% by weight, 0.2~10% by weight, 0.25~7.5% by weight, 0.5~5% by weight, or even 0.75~3% by weight. From the perspective of suppressing the loss of total light transmittance in the optical laminate 10, the smaller the above percentage, the better.

The antistatic layer 2 may contain one or more types of conductive particles.

The antistatic layer 2 may also contain materials other than conductive particles. Examples of other materials include binder resins. In other words, the antistatic layer 2 may also contain binder resins. The presence of binder resins can help improve the film-forming properties of the antistatic layer 2 or improve the adhesion and bonding (anchoring force) of the antistatic layer 2 to the optical thin film 3.

Examples of adhesive resins include: acezoline-containing polymers, polyurethane resins, polyester resins, acrylic resins, polyether resins, cellulose resins, polyvinyl alcohol resins, epoxy resins, polyvinylpyrrolidone, polystyrene resins, polyethylene glycol, and neopentyl tertrol. The adhesive resin is preferably an acezoline-containing polymer, polyurethane resin, polyester resin, or acrylic resin, and particularly preferably a polyurethane resin and/or an acrylic resin. The antistatic layer 2 may contain one or more adhesive resins, or may contain only one. The combination of two or more adhesive resins can also be a combination of polyurethane resin and acrylic resin. The content of the adhesive in the antistatic layer 2 is, for example, 1~99.99% by weight, or 50~99.99% by weight, 60~99.99% by weight, 70~99.99% by weight, 80~99.99% by weight, or even 90~99.99% by weight.

The glass transition temperature (Tg) of the binder resin can be above 0°C, or above 20°C, 30°C, 40°C, 50°C, or 55°C, and even above 60°C. The upper limit of Tg is, for example, below 100°C. In other words, the antistatic layer 2 can also contain a binder resin with a Tg of 0°C or higher. According to the inventors' review, when using a binder resin, a Tg within the above-mentioned range can help suppress the change in the state of conductive particles in the antistatic layer 2 before and after the DIN test. We hypothesize that the higher the Tg of the binder resin, the better it can suppress the movement of conductive particles contained in the antistatic layer 2 due to heat and the resulting excessive aggregation or orientation. Unless otherwise specified, the Tg values for polymers in this manual refer to the Tg obtained from the Fox formula based on the composition of the monomer components. Unless otherwise specified, the Tg values for resins (including binder resins) in this manual refer to the Tg obtained by differential scanning calorimetry (DSC). The DSC measurement conditions are as follows: • Ambient gas: Nitrogen (50 mL/min) • Measurement temperature range: 0℃→100℃ • Heating rate: 10℃/min • Sample volume: Approximately 3 mg (a sample container such as an aluminum Tzero plate can be used).

When the antistatic layer 2 contains an adhesive resin with a Tg of 0°C or higher, the percentage of the adhesive resin with a Tg of 0°C or higher in the total adhesive resin content can be 50% by weight or higher, or 55% by weight or higher, 60% by weight or higher, 65% by weight or higher, 70% by weight or higher, 75% by weight or higher, 80% by weight or higher, 85% by weight or higher, 90% by weight or higher, 91% by weight or higher, 92% by weight or higher, 93% by weight or higher, and even 94% by weight or higher. The upper limit of this percentage is, for example, 100% by weight or lower, or 99% by weight or lower, 98% by weight or lower, 97% by weight or lower, 96% by weight or lower, and even 95% by weight or lower.

The antistatic layer 2, especially when containing two or more binder resins, may also contain binder resins with a Tg below 0°C. For example, the antistatic layer 2 may also contain binder resins with a Tg above 0°C and binder resins with a Tg below 0°C. The lower limit of the Tg of the binder resin with a Tg below 0°C is, for example, above -50°C, above -45°C, or even above -40°C. Depending on the composition of the antistatic layer 2, the binder resin with a Tg below 0°C may help improve its film-forming properties or improve the dispersibility of CNTs during the film formation of the antistatic layer 2. When the antistatic layer 2 comprises adhesive resins with a Tg of 0°C or higher and adhesive resins with a Tg of 0°C or lower, the proportion of the adhesive resins with a Tg of 0°C or lower in the total amount of adhesive resins may be 50% by weight or less, or 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 may be, for example, 1% by weight or more, or 2% by weight or more, 3% by weight or more, 4% by weight or more, or even 5% by weight or more.

The antistatic layer 2 may contain a leveling agent. However, the content of the leveling agent in the antistatic layer 2 should be low. According to the inventors' review, not adding a leveling agent to the coating solution used to form the antistatic layer 2 helps to suppress changes in the state of conductive particles in the antistatic layer 2 before and after the DIN test. The leveling agent may promote the movement of conductive particles contained in the antistatic layer 2 due to heat. The content of the leveling agent can also be less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, and even less than 0.1% by weight. The antistatic layer 2 may also be substantially free of leveling agent. In this specification, "substantially free" means a content of less than 0.01% by weight.

The conductive particles contained in the antistatic layer 2 may affect the light transmittance of the optical laminate 10. According to the inventors' research, when the content of conductive particles is the same, the lower the dispersion of the conductive particles, the more likely the light transmittance of the optical laminate 10 will decrease. From this point of view, the loss of total light transmittance of the optical laminate 10 due to the antistatic layer 2 can also be less than 1.0%. The loss of total optical transmittance can be below 0.90%, 0.80%, 0.70%, 0.60%, 0.50%, 0.45%, 0.40%, 0.35%, 0.30%, 0.25%, 0.20%, 0.15%, or 0.12%, and can even be below 0.10%. Lower total optical transmittance loss is better. The loss of total optical transmittance can be determined by measuring the total optical transmittance T2 of the optical laminate 10 being evaluated and the total optical transmittance T1 of an optical laminate with the same composition except for the absence of the antistatic layer 2, and then identifying the difference between the two (T1-T2). In this manual, total optical transmittance refers to the transmittance of light in the wavelength range of 380~700nm. Total optical transmittance can be measured according to the Japanese Industrial Standard (hereinafter referred to as JIS) K7361-1:1997. However, the total optical transmittance is measured using a D65 light source. Furthermore, the light used for measurement is incident from three sides of the optical thin film.

The thickness of the antistatic layer 2 can be, for example, 5~1500nm, or below 1400nm, 1300nm, 1200nm, 1100nm, 1000nm, 900nm, 800nm, 700nm, 600nm, 500nm, 400nm, 300nm, 200nm, 180nm, 150nm, 120nm, 100nm, 90nm, 80nm, 70nm, 60nm, 55nm, 50nm, 45nm, 40nm, or even below 35nm. The thickness can also be above 10nm, above 20nm, greater than 20nm, above 25nm, or even above 30nm. Furthermore, according to the inventors' research, for antistatic layers 2 with the same composition and formation method, there is a tendency that the smaller the thickness, the smaller the loss of the above-mentioned total light transmittance.

The surface resistivity of the antistatic layer 2 after DIN testing is, for example, below 1.0 × ^10⁹ Ω/□. The surface resistivity after DIN testing can also be below 5.0 × ^10⁸ Ω/□, below 2.0 × ^10⁸ Ω/□, below 1.0 × ^10⁸ Ω/□, below 9.0 × ^10⁷ Ω/□, below 8.0 × ^10⁷ Ω/□, below 7.0 × ^10⁷ Ω/□, below 6.0 × ^10⁷ Ω/□, below 5.0 × ^10⁷ Ω/□, below 4.0 × ^10⁷ Ω/□, and even below 3.0 × ^10⁷ Ω/□. The lower limit of the surface resistivity is, for example, 1.0× ^10⁶ Ω/□ or higher, and may also be 2.0× ^10⁶ Ω/□ or higher, 3.0× ^10⁶ Ω/□ or higher, 4.0× ^10⁶ Ω/□ or higher, 5.0× ^10⁶ Ω/□ or higher, 6.0× ^10⁶ Ω/□ or higher, 7.0× ^10⁶ Ω/□ or higher, 8.0× ^10⁶ Ω/□ or higher, 9.0× ^10⁶ Ω/□ or higher, and may even be 1.0× ^10⁷ Ω/□ or higher.

The range of surface resistivity that can be used for the antistatic layer 2 before the DIN test is the same as the range of surface resistivity that can be used after the DIN test. The surface resistivity A after the DIN test can be 1.0× ^10⁶ Ω/□ or higher and 3.0× ^10⁸ Ω/□ or lower, or 1.0× ^10⁷ Ω/□ or higher and 1.0× ^10⁸ Ω/□ or lower, or even 1.0× ^10⁷ Ω/□ or higher and 5.0× ^10⁷ Ω/□ or lower.

The surface resistivity of the antistatic layer 2 can be determined by the following method. Prepare a laminate with the surface of the antistatic layer 2 exposed to the outside. An example of this laminate is a laminate comprising an optical thin film 3 and the antistatic layer 2. Next, measure the surface resistivity of the exposed surface of the antistatic layer 2 in the prepared laminate. The surface resistivity can be measured using a high-resistivity resistivity meter (for example, the Hiresta series manufactured by Mitsubishi Chemical Analytech Co., Ltd.), following the method specified in Japanese Industrial Standard (JIS) K6911:1995. The surface resistivity measurement is performed at 25±3°C.

The antistatic layer 2 may also contain CNTs and an adhesive resin with a Tg of 0°C or higher. In this case, the length of the CNTs may be 3µm or more and 300µm or less, and the diameter may be 10nm or less.

≪1-2. Adhesive Sheet≫ Adhesive sheet 1 is typically a layer formed of an adhesive composition (I) containing a polymer (A).

<1-2-a. Polymer (A)> Examples of polymer (A) are (meth)acrylate polymers, carbamate polymers, polysiloxane polymers, and rubber polymers. Polymer (A) is preferably a (meth)acrylate polymer. Adhesive composition (I) may also contain a (meth)acrylate polymer as a main component; in other words, adhesive composition (I) may also be an acrylic adhesive composition. In this specification, the main component means the component with the highest content by weight in the composition. The content of the main component may be, for example, 50% by weight or more, or 60% by weight or more, 70% by weight or more, 75% by weight or more, or even 80% by weight or more. In this specification, a (meth)acrylate polymer means a polymer having structural units derived from (meth)acrylate monomers such as (meth)acrylates. The content of the structural unit in the (meth)acrylic polymer is, for example, 40% by weight or more, or 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 also be composed solely of structural units derived from (meth)acrylic monomers.

Polymer (A) may also have a polyether structure. Adhesive composition (I) may also include polymer (A) having a polyether structure as a main component. A polyether structure is a structure containing at least two ether groups (-O-). The polyether structure may be linear or branched. An example of a polyether structure includes an alkyl group that may be linear or branched and at least two ether groups. Polymer (A) may have a polyether structure in its main chain or in its side chains, preferably in its side chains. Polymer (A) may also be a (meth)acrylic polymer having a polyether structure in its side chains.

Polymer (A) may also have structural units with polyether structures. In such structural units, the polyether structure may be located on the main chain or on the side chain, preferably on the side chain. Polymer (A) may also have structural units derived from (meth)acrylic monomers with polyether structures on the side chains.

Polymer (A) having a polyether structure in its side chains, for example, has a structural unit derived from monomer A1 as shown in formula (2) below. In other words, polymer (A) may also have a structural unit derived from monomer as shown in formula (2) below. ^R1 in formula (2) is a hydrogen atom or a methyl group. ^R2 is an alkyl group that may be linear or branched, preferably a linear alkyl group. The number of carbon atoms in the alkyl group may be 1 to 10, more preferably 1 to 4. Examples of ^R2 are methyl and ethyl. n is an integer from 1 to 15, preferably an integer from 1 to 10, more preferably an integer from 1 to 5. When n is 1, monomer A1 contains a "-O-" of a COO group and contains 2 ether groups. Monomer A1 is one of the (meth)acrylate monomers, and more specifically, one of the (meth)acrylate monomers. When focusing on the ^R2O group at the end of the side chain, monomer A1 is also a type of alkoxy (meth)acrylate monomer. The structural unit derived from monomer A1 has a polyether structure in the side chain.

[Chemical Formula 2]

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). Structural units derived from monomer A1 can help reduce the surface resistivity of the adhesive sheet 1 formed from the adhesive composition (I).

The content of polyether structural units in polymer (A) may be 0% by weight or more, or 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 may even be 50% by weight or more. The upper limit of this content is, for example, 100% by weight or less, or 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 may even be less than 60% by weight. Furthermore, the content of structural units derived from monomer A1 in polymer (A) may also be within the above range.

Polymer (A) may also not have structural units with polyether structures.

Polymer (A) may also have one or more structural units derived from monomer A2. Monomer A2 may also be copolymerized with monomer A1. Polymer (A) may also have both structural units derived from monomer A1 and structural units derived from monomer A2.

Examples of monomer A2 are (meth)acrylate monomers having alkyl groups with 1 to 30 carbon atoms in the side chain. The alkyl groups can be linear or branched. Examples of such (meth)acrylate monomers include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, dibutyl methacrylate, terbutyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, isohexyl methacrylate, isoheptyl methacrylate, and methacrylate. 2-Ethylhexyl acrylate, 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) (laurate), n-tetrazol (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecanyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, and n-octadecyl (meth)acrylate. The content of structural units derived from the above-mentioned (meth)acrylate monomers 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, and may even be 5% by weight or less, or may be 0% by weight (or may not contain the structural unit).

Another example of monomer A2 is a hydroxyl-containing monomer. Hydroxyl-containing monomers can also be hydroxyl-containing (meth)acrylate monomers. Examples of hydroxyl-containing monomers include: hydroxyalkyl esters of (meth)acrylate such as 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, and 12-hydroxylauryl methacrylate, as well as (4-hydroxymethylcyclohexyl)-methacrylate. From the viewpoint of improving the durability of the adhesive sheet 1 formed from adhesive composition (I), 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, and preferably 4-hydroxybutyl methacrylate are preferred. The content of structural units derived from hydroxyl-containing monomers in polymer (A) is, for example, 1 to 5% by weight, or less than 3% by weight, or even less than 2% by weight. Polymer (A) may also not have structural units derived from hydroxyl-containing monomers.

Monomer A2 can also be an aromatic ring monomer, a carboxyl monomer, an amino monomer, or a amide monomer.

The aromatic ring monomer can also be an aromatic ring (meth)acrylate monomer. Examples of aromatic ring monomers include: phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxy diethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, hydroxyethylated β-naphthol (meth)acrylate, and biphenyl (meth)acrylate. When manufacturing and/or using an image display device comprising optical laminate 10, birefringence can occur due to adhesive sheet misalignment. If birefringence occurs, problems such as light leakage or uneven display may arise in the image display device. The presence of structural units derived from aromatic ring monomers can help reduce birefringence caused by the aforementioned adhesive sheet misalignment.

The aromatic ring monomer can also be monomer A3 as shown in formula (3). ^R3 in formula (3) is a hydrogen atom or a methyl group. ^R4 in formula (3) is a phenyl group that can be replaced by a hydrogen atom, preferably a phenyl group. The substituents for the hydrogen atom are, for example, linear or branched alkyl groups having 1 to 10 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)acrylate monomer, and more specifically, a type of (meth)acrylate monomer. Monomer A3 contains the "-O-" of the COO group and contains two ether groups. In other words, the structural unit derived from monomer A3 is also a structural unit with a polyether structure. Furthermore, the content of structural units derived from monomer A3 in polymer (A) is included in the content of structural units with polyether structures.

[Chemical Formula 3]

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

Polymer (A) having structural units derived from monomer A3 can help improve the durability of optical laminate 10. Furthermore, polymer (A) having structural units derived from monomer A3 can still help suppress the offset of optical film 3 at its ends even when optical laminate 10 includes optical film 3 that may shrink due to heating.

Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of amine-containing monomers include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of amide-containing monomers include (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-hydroxymethyl (meth)acrylamide, N-hydroxymethyl-N-propane (meth)acrylamide, and aminomethyl (meth)acrylamide. Acrylamide monomers such as acrylamide, aminoethyl (meth)acrylamide, methyl (meth)acrylamide and ethyl (meth)acrylamide; N-acrylyl heterocyclic monomers such as N-(meth)acrylamide molfolin, N-(meth)acrylamide piperidine and N-(meth)acrylamide pyrrolidine; and N-vinylpyrrolidone and N-vinyl-ε-caprolactam monomers containing N-vinyl lactone.

Monomer A2 can also be a multifunctional monomer. Examples of multifunctional monomers include: hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl tetraethylene di(meth)acrylate, neopentyl tetraethylene tri(meth)acrylate, dinepentyl tetraethylene hexa(meth)acrylate, tetrahydroxymethylmethane tri(meth)acrylate, allyl (meth)acrylate, ethylene (meth)acrylate, epoxy acrylates, polyester acrylates, and carbamate acrylates, as well as divinylbenzene. Multifunctional acrylates are preferably 1,6-hexanediol diacrylate and dinepentyl tetraethylene hexa(meth)acrylate.

The total content of structural units derived from aromatic ring monomers, carboxyl monomers, amine monomers, amide monomers, and polyfunctional monomers in polymer (A) should preferably be 20% by weight or less, more preferably 15% by weight or less, more preferably 10% by weight or less, and especially preferably 8% by weight or less. When polymer (A) contains such structural units, the total content may be, for example, 0.01% by weight or more, 1% by weight or more, 2% by weight or more, and more preferably 3% by weight or more. Polymer (A) may also not contain such structural units. In particular, the content of structural units derived from carboxyl monomers in polymer (A) may be less than 0.1% by weight or may be 0% by weight (or may not contain such structural units).

Other examples of monomer A2 include: acrylic acid; cyanoacrylates such as (meth)acrylonitrile; epoxy-containing monomers such as (meth)acrylate and (meth)acrylate methoxypropyl ester; sulfonic acid monomers such as sodium vinylsulfonate; phosphate-containing monomers; (meth)acrylates with alicyclic hydrocarbon groups such as (meth)acrylate cyclopentyl ester, (meth)acrylate cyclohexyl ester, and (meth)acrylate isocamphenyl ester; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; alkenes or dienes such as ethylene, propylene, butadiene, isoprene, and isobutene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

The total content of structural units derived from other monomers A2 in polymer (A) is, for example, less than 30% by weight, less than 10% by weight, and preferably less than 0% by weight (not having the structural unit).

Polymer (A) may have structural units derived from (meth)acrylic monomers with a glass transition temperature (Tgh) above -55°C when forming the homopolymer, structural units derived from (meth)acrylic monomers with a Tgh above -40°C, structural units derived from (meth)acrylic monomers with a Tgh above -30°C, or structural units derived from (meth)acrylic monomers with a Tgh above -10°C. Examples of the above structural units are structural units derived from monomer A3 and structural units derived from (meth)acrylic monomers with 1 to 3 carbon alkyl groups on the side chain. Polymer (A) may also have at least one structural unit selected from the group consisting of structural units derived from monomer A3 and structural units derived from (meth)acrylic monomers with 1 to 3 carbon atoms in their side chains. Polymer (A) having the above-mentioned structural units may help improve the durability of optical laminate 10.

Polymer (A) can be formed by polymerizing one or more of the aforementioned monomers using known methods. It can also be formed by polymerizing monomers with a portion of the polymer. Polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy line polymerization. From the viewpoint of forming adhesive sheets with excellent optical transparency, solution polymerization and active energy line polymerization are preferable. Polymerization should avoid contact between the monomers and/or a portion of the polymer and oxygen; therefore, polymerization can be carried out, for example, in an inert gas environment such as nitrogen, or in a state where oxygen is blocked by a resin film, etc. The resulting polymer (A) can be any of the following: random copolymer, block copolymer, graft copolymer, etc.

The polymerization system that forms polymer (A) may also contain one or more polymerization initiators. The type of polymerization initiator may be selected according to the polymerization reaction, and may be, for example, a thermal polymerization initiator or a photopolymerization initiator.

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 also be a mixture of two or more solvents.

The polymerization initiators used in solution polymerization include, for example, azo-based polymerization initiators, peroxide-based polymerization initiators, and redox-based polymerization initiators. Examples of peroxide-based polymerization initiators include dibenzoxyl peroxide and tributyl maleate peroxide. Among these, the azo-based polymerization initiator disclosed in Japanese Patent Application Publication No. 2002-69411 is particularly suitable. Examples of such azo-based polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, and 4,4'-azobis-4-cyanopentanoic acid. However, the polymerization initiator is not limited to the examples above. The amount of azo polymerization initiator used is, for example, 0.05 to 0.5 parts by weight relative to 100 parts by weight of the total monomer, or 0.1 to 0.3 parts by weight.

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

Examples of photopolymerization initiators include: benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, diphenyl ketone-based photopolymerization initiators, ketal-based photopolymerization initiators, and 9-oxosulfuron-methyl-2-ethylhexylene ... It is a photopolymerization initiator. However, photopolymerization initiators are not limited to the above examples.

Examples of benzoin ether-based photopolymerization initiators include: benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethyl-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include: 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(tri-butyl)dichloroacetophenone. Examples of α-ketool-based photopolymerization initiators include: 2-methyl-2-hydroxyphenylacetone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylprop-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Photoactive oxime photopolymerization initiators include, for example, 1-benzyl-1,1-propanedione-2-(orthoethoxycarbonyl)-oxime. Benzoin-based photopolymerization initiators include, for example, benzoin. Benzyl-based photopolymerization initiators include, for example, benzyl. Diphenyl ketone-based photopolymerization initiators include, for example, diphenyl ketone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxydiphenyl ketone, polyvinyl diphenyl ketone, and α-hydroxycyclohexylphenyl ketone. Ketone-based photopolymerization initiators include, for example, benzyl dimethyl ketone. 9-Oxysulfuron Photopolymerization initiators, for example, include 9-oxosulfuron. 2-Chloro-9-oxysulfur 2-Methyl-9-oxosulfur 2,4-Dimethyl-9-oxosulfur Isopropyl 9-oxosulfur 2,4-Diisopropyl-9-oxosulfuron Dodecyl 9-oxosulfur .

The amount of photopolymerization initiator used is, for example, 0.01 to 1 part by weight relative to 100 parts by weight of the total amount of monomers, or 0.05 to 0.5 parts by weight.

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) can suppress cracking of the adhesive sheet and inhibit the tendency for viscosity to increase or gel. The weight-average molecular weight (Mw) of the polymer in this specification is a value determined by GPC (Gel Permeation Chromatography) (converted from polystyrene).

The content of polymer (A) in the adhesive composition (I), in terms of solid content, is, for example, 50% by weight or more, or 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, or 97% by weight or less, or even 95% by weight or less.

<1-2-b. Antistatic Agent> The adhesive composition (I) may also contain an antistatic agent. The antistatic agent helps to reduce the surface resistivity of the adhesive sheet 1. Examples of antistatic agents are ionic compounds such as salts. Ionic compounds may also be ionic liquids that are liquid at room temperature (25°C).

Examples of ionic compounds are inorganic cation salts and organic cation salts. Examples of inorganic cation salts are inorganic cation-anion salts. Examples of cations contained in inorganic cation salts are alkali metal ions. Alkali metal ions include, for example, lithium ions, sodium ions, and potassium ions, preferably lithium ions. Inorganic cation salts can also be lithium salts.

Examples of anions contained in inorganic cation salts include: 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 anions represented by the following general formulas ( a ) to ( d ) . (a) (C  n F2n + 1 </sub>SO 2 ) 2 N - (n is an integer from 1 to 10) (b) CF 2 (C  m  F2m SO 2) 2 N - (m is an integer from 1 to 10) (c) -O 3 S(CF 2 ) lSO  3  - (l is an integer from 1 to 10) (d) (C p  F  2p  + 1</sub>SO2)N - (C q F2q + 1 </sub>SO2 ) (p and q are independent integers from 1 to 10)

The anions contained in inorganic cation salts should preferably be fluorinated anions, and more preferably fluoroimid anions. Examples of fluoroimid anions are imid anions with perfluoroalkyl groups. More specific examples of fluoroimid anions are ( _CF3SO2 )( _CF3CO ) ^N- , or anions represented by the above general formulas (a), (b), or (d ⁾ , preferably ( _CF3SO2 ) _2N- , ( _C2F5SO2 ) _{2N- ,} ^etc. , which are ( _{perfluoroalkylsulfonyl )} imids represented by general formula (a) _, and more preferably ^bis (trifluoromethanesulfonyl)imids represented by ( _CF3SO2 ) _{2N- .} An ideal example of an inorganic cation salt is lithium bis(trifluoromethanesulfonyl) aceimine (LiTFSI).

Organic cation salts are organic cation-anion salts. Examples of cations contained in organic cation salts are organic onions containing an organic group. Examples of onions contained in organic onions are nitrogen-containing onions, sulfur-containing onions, and phosphorus-containing onions, preferably nitrogen-containing onions and sulfur-containing onions. Examples of nitrogen-containing onions include: ammonium cations, piperidinium cations, pyrrolidineonium cations, pyridinium cations, cations with a dihydropyrrole skeleton, cations with a pyrrole skeleton, imidazodium cations, tetrahydropyrimidineonium cations, dihydropyrimidineonium cations, pyrazolium cations, and pyrazolineonium cations. Examples of sulfur-containing onions include strontium cations. Examples of phosphorus-containing onions include phosphonium cations. Examples of organic groups in organic onions include alkyl, alkoxy, and alkenyl groups. Ideal examples of organonium are tetraalkylammonium cations (e.g., tributylmethylammonium cations), alkylpiperidineonium cations, alkylpyrrolidineonium cations, etc.

The anions contained in organic cation salts are the same as those contained in inorganic cation salts. Ideal examples of organic cation salts include 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imidine (EMI-FSI) and trimethylbutylammonium bis(trifluoromethanesulfonyl)imidine.

Antistatic agents can also be used in combination with inorganic and organic cation salts. Antistatic agents should preferably contain organic cation salts.

In the adhesive composition (I), the amount of antistatic agent mixed with 100 parts by weight of polymer (A) is, for example, 0.5 parts by weight or more, or 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 mixing amount relative to 100 parts by weight of polymer (A) is, for example, less than 30 parts by weight, or less than 20 parts by weight, less than 15 parts by weight, less than 12 parts by weight, less than 10 parts by weight, less than 9 parts by weight, less than 8 parts by weight, less than 7 parts by weight, or even less than 6 parts by weight. By appropriately adjusting the mixing amount of antistatic agent in the adhesive composition (I), the durability of the adhesive sheet 1 can be further improved.

<1-2-c. Free radical scavengers> Adhesive components (I) may also contain free radical scavengers. Examples of free radical scavengers are various antioxidants such as hindered phenolic, hindered amine, phosphite, phenolic and thioether systems, and admixtures of these systems.

Types of antioxidants include free radical chain inhibitors and peroxide decomposers.

Antioxidants may also be selected from at least one of the hindered phenolic, hindered amine, and phosphite systems.

Hindered phenolic antioxidants may also have the following structure: at least one carbon atom adjacent to the carbon atom of the aromatic ring with an OH group bonded to phenol is bonded with a tertiary butyl group. Examples of hindered phenolic antioxidants include: butylhydroxytoluene (BHT); and 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).

Hindered amine antioxidants may also have at least one hindered piperidinium group in one molecule. Examples of hindered amine antioxidants are ADK STAB LA-63, ADK STAB LA-63P, ADK STAB LA-52 and ADK STAB LA-57 (all trade names, manufactured by ADEKA).

Examples of phosphite antioxidants include: triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite; as well as ADK STAB 2112, ADK STAB 2112RG, ADK STAB 1178, and ADK STAB 3010 (all trade names, manufactured by ADEKA).

Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and high molecular weight phenolic antioxidants. Examples of monophenolic antioxidants include 2,6-di-tertiary butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tertiary butyl-4-ethylphenol, and stearyl-β-(3,5-di-tertiary butyl-4-hydroxyphenyl)propionate. Examples of bisphenol antioxidants include: 2,2'-methylenebis(4-methyl-6-tertiary-butyrolactone), 2,2'-methylenebis(4-ethyl-6-tertiary-butyrolactone), 4,4'-thiobis(3-methyl-6-tertiary-butyrolactone), 4,4'-butylenebis(3-methyl-6-tertiary-butyrolactone), and 3,9-bis[1,1-dimethyl-2-[β-(3-tertiary-butyl-4-hydroxy-5-methylphenyl)propoxy]ethyl]2,4,8,10-tetraoxozoispiro[5,5]undecane. Examples of high molecular weight phenolic antioxidants include: 1,1,3-tris(2-methyl-4-hydroxy-5-tritertiary butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tritertiary butyl-4-hydroxybenzyl)benzene, tetra-[methylene-3-(3',5'-di-tritertiary butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tritertiary butylphenyl)butyrate]diol ester, 1,3,5-tris(3',5'-di-tritertiary butyl-4'-hydroxybenzyl)-S-tris(2,4,6-(1H,3H,5H)trione, and tocopherol.

Examples of thioether-based antioxidants include ADK STAB AO-503 and ADK STAB AO-26 (both trade names, manufactured by ADEKA).

The molecular weight of free radical scavengers (e.g., antioxidants) can be below 1000, or below 900, 850, 800, 700, 600, 500, 450, and even below 400. The lower limit of the molecular weight is, for example, above 100. According to the inventors' research, free radical scavengers with molecular weights within the above range are particularly suitable for inhibiting the generation of free radicals in adhesive sheets formed by the adhesive composition (I).

Free radical scavengers (such as antioxidants) can also be in liquid form at 25°C.

In the adhesive composition (I), the amount of free radical scavenger mixed with 100 parts by weight of polymer (A) is, for example, 0.1 parts by weight or more, or 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 mixing amount with 100 parts by weight of polymer (A) is, for example, 15 parts by weight or less, or 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.

<1-2-d. Additives> The adhesive composition (I) may also 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, refining agents, softeners, polymerization inhibitors, rust inhibitors, inorganic fillers, organic fillers, metal powders, and other powders, particles, and foils. The additives may be mixed in a total of, for example, less than 10 parts by weight, preferably less than 5 parts by weight, and more preferably less than 3 parts by weight, relative to 100 parts by weight of polymer (A).

Examples of crosslinking agents include organic crosslinking agents and multifunctional metal chelates. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Organic crosslinking agents and multifunctional metal chelates can also be used with any type of adhesive composition (I) in solvent-based and active energy line-curing types. When adhesive composition (I) is solvent-based, the crosslinking agent should preferably be a peroxide-based crosslinking agent or an isocyanate-based crosslinking agent. Peroxide-based crosslinking agents and isocyanate-based crosslinking agents can also be used together. The adhesive composition (I) may contain an isocyanate crosslinker, a peroxide crosslinker, or both an isocyanate crosslinker and a peroxide crosslinker.

Examples of isocyanate crosslinking agents include: aromatic isocyanate compounds such as toluene diisocyanate, chlorophenyl diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, and polymethylene polyphenyl isocyanate; alicyclic isocyanate compounds such as pentoamyl diisocyanate, pentohexyl diisocyanate, hydrogenated diphenylmethane diisocyanate, and isoflavone diisocyanate; and aliphatic isocyanate compounds such as pentobutyl diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. The isocyanate crosslinking agent can also be: a compound formed by adding the above-mentioned isocyanate compound to a polyol compound such as trihydroxypropane (adduct); a compound formed by reacting the above-mentioned isocyanate compound with polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and polyisoprene polyol; or a derivative of the above-mentioned isocyanate compound such as a trimerocyanate. Specific examples of derivatives are: trihydroxypropane/toluene diisocyanate trimer adduct (e.g., Coronate L manufactured by Tosoh), trihydroxypropane/hexamethylene diisocyanate trimer adduct (e.g., Coronate HL manufactured by Tosoh), and a trimerocyanate of hexamethylene diisocyanate (e.g., Coronate HX manufactured by Tosoh).

When the adhesive composition (I) contains an isocyanate-based crosslinker, the amount of the isocyanate-based crosslinker mixed with 100 parts by weight of polymer (A) is, for example, 0.1 to 10 parts by weight, or 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.

Examples of peroxide-based crosslinkers include: di(2-ethylhexyl)peroxydicarbonate, di(4-trimethylbutylcyclohexyl)peroxydicarbonate, di-dibutyl peroxydicarbonate, tributyl neodecanoate peroxide, trihexyl peroxytrimethylacetate, tributyl peroxytrimethylacetate, dilauryl peroxide, di-n-octyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, benzoyl peroxide, tributyl peroxyisobutyrate, and 1,1-di(trimethylhexylperoxy)cyclohexane. Considering the excellent crosslinking efficiency, benzoyl peroxide can also be used as a peroxide-based crosslinker.

When the adhesive composition (I) contains a peroxide-based crosslinker, the amount of the peroxide-based crosslinker mixed with 100 parts by weight of polymer (A) is, for example, 0.005 to 5 parts by weight, or 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.

Examples of silane coupling agents include: 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 2-(3-4-epoxycyclohexyl)ethyltrimethoxysilane, and other epoxy-containing silane coupling agents; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3 -Triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane and other silane coupling agents containing amino groups; 3-propenyloxypropyltrimethoxysilane, 3-methpropenyloxypropyltriethoxysilane and other silane coupling agents containing (meth)propenyl groups; 3-isocyanate propyltriethoxysilane and other silane coupling agents containing isocyanate groups.

When the adhesive composition (I) contains a silane coupling agent, the amount of silane coupling agent mixed with 100 parts by weight of polymer (A) is, for example, 5 parts by weight or less, or 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, and even 0.05 parts by weight or less. The adhesive composition (I) may also be free of silane coupling agent.

The types of adhesive composition (I) include, for example, latex type, solvent type (solution type), active energy line curing type (photocuring type), and thermosetting type (thermosetting type). From the viewpoint of forming adhesive sheets with excellent durability, adhesive composition (I) can be solvent type or active energy line curing type, or it can be solvent type. Solvent type adhesive composition (I) may also not contain photocuring agents such as UV curing agents.

<1-2-e. Surface Resistivity> The surface resistivity of the adhesive sheet 1 may be less than 1.0×10 ¹³ Ω/□, or less than 1.0×10 ¹² Ω/□, less than 1.0×10 ¹¹ Ω/□, less than 1.0×10 ¹⁰ Ω/□, less than 1.0×10 ⁹ Ω/□, less than 8.0×10 ⁸ Ω/□, less than 5.0×10 ⁸ Ω/□, less than 3.0×10 ⁸ Ω/□, less than 2.0×10 ⁸ Ω/□, less than 1.0×10 ⁸ Ω/□, less than 8.0×10 ⁷ Ω/□, less than 5.0×10 ⁷ Ω/□, and even less than 2.0×10 ⁷ Ω/□. The lower limit of the surface resistivity is, for example, 1.0 × ^10⁶ Ω/□ or higher, or 1.0 × ^10⁷ Ω/□ or higher, or even 1.0 × ^10⁸ Ω/□ or higher. The adhesive sheet 1 can have a surface resistivity within the above range at a time point before the DIN test, and can also have a surface resistivity within the above range at a time point after the DIN test.

≪1-3. Optical Thin Film≫ The optical thin film 3 may include, for example, at least one selected from the group consisting of polarizing thin films and retardation thin films. The optical thin film 3 may also include a polarizing thin film. The optical thin film 3 may also be a laminated thin film including a polarizing thin film and/or a retardation thin film. The optical thin film 3 may also include a glass thin film.

<1-3-a. Polarizing Film> A polarizing film includes a polarizing element. A polarizing film includes a polarizing element and a protective film (transparent protective film) disposed on at least one side of the polarizing element. The protective film is typically disposed in contact with the main surface of the polarizing element. The polarizing element may also be disposed between two protective films. The protective film may also be disposed on both sides of the polarizing element. The protective film may be a single layer or a laminate of two or more layers.

Regarding polarizing elements, there are no particular limitations. Examples include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formaldehyde-modified PVA films, and partially saponified ethylene-vinyl acetate copolymer films, which are obtained by adsorbing dichroic substances such as iodine and dichroic dyes and then uniaxially extending them; and polyene-based oriented films such as dehydrated PVA products and dehydrochlorinated polyvinyl chloride products. Polarizing elements are typically composed of PVA films (including partially saponified ethylene/vinyl acetate copolymer films) and dichroic substances such as iodine.

There is no particular limitation on the thickness of the polarizing element; for example, it can be less than 80µm, or less than 50µm, 30µm, or 25µm, or even less than 20µm. There is also no particular limitation on the lower limit of the polarizing element's thickness; for example, it can be greater than 1µm, or greater than 5µm, 10µm, or even greater than 15µm. Suppressing dimensional variations in thin polarizing elements (e.g., less than 20µm thick) can help improve the durability of optical laminates, especially their durability at high temperatures.

Regarding the material for the protective film, thermoplastic resins with excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy can be used. Specific examples of such thermoplastic resins include: cellulose resins such as triacetate cellulose, polyester resins, polyether ether resins, polyether ether resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylate resins, cyclic polyolefin resins (norphine resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The protective film can also be made of thermosetting resins or UV-curing resins such as (meth)acrylic, carbamate, acrylate, epoxy, and polysiloxane. When the polarizing film has two protective films, the materials of the two protective films can be the same or different. For example, a protective film made of thermoplastic resin can be laminated to one main surface of the polarizer with an adhesive, and a protective film made of thermosetting or UV-curing resin can be laminated to the other main surface of the polarizer. The protective film may also contain one or more additives. Additives include, for example, UV absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

The moisture permeability of the protective film is not particularly limited, and can be below 200 g/( ^m² ·day) or below 50 g/( ^m² ·day). This inhibits the intrusion of moisture from the air into the polarizing film, thus suppressing changes in the moisture content of the polarizing film. This, in turn, prevents the polarizing film from warping or changing in size. Furthermore, when a protective film with moisture permeability limited to the above range is disposed between the adhesive sheet 1 and the polarizing element, it helps to prevent free radicals from migrating from the adhesive sheet 1 at high temperatures. Materials used to form a protective film with low moisture permeability include, for example, polyester polymers, polycarbonate polymers, aryl ester polymers, amide polymers, olefin polymers, cyclic olefin polymers, (meth)acrylic polymers, and mixtures thereof.

The moisture permeability of the protective film can be determined according to the moisture permeability test (permeability cup method) in JIS Z0208:1976, using the following method: First, cut the protective film into 60mm diameter pieces to prepare the test sample. Next, place the test sample in a permeability cup containing approximately 15g of calcium chloride. Place the permeability cup in a constant temperature chamber set at 40°C and 92%RH for 24 hours to conduct the moisture permeability test. By measuring the increase in the weight of calcium chloride before and after the test, the moisture permeability of the protective film can be determined.

The thickness of the protective film can be appropriately determined, but generally it is around 10~200μm, depending on factors such as strength, operability, and film properties.

Polarizing components and protective films are typically bonded together using water-based adhesives. 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 polarizing plates exhibit suitable adhesion to various protective films. Adhesives may also contain metallic compound fillers.

In polarizing films, phase retardation films or the like can be formed on the polarizing element to replace the protective film. Further operations such as setting other protective films or phase retardation films can also be performed on the protective film.

A polarizing film can be specifically defined as a laminate containing a polarizing element and wherein the layers therein are bonded together by an adhesive.

Regarding the protective film, a hard coating can be applied to the surface opposite to the surface that is in contact with the polarizer, or treatments can be performed for purposes such as anti-reflection, anti-adhesion, diffusion, and anti-glare.

Polarizing films can also be circularly polarized films.

The curl diameter of the polarizing film, evaluated by the following test method, can be 3 mm or more, or 4 mm or more, 5 mm or more, 5.5 mm or more, 6 mm or more, 6.5 mm or more, 7 mm or more, and even 7.5 mm or more. The larger the curl diameter, the better the polarizing film suppresses curling caused by heat. Furthermore, the use of polarizing films with large curl diameters, for example, when forming an antistatic layer 2 on the polarizing film, is suitable for suppressing curling while increasing the heating temperature during formation. <Test Method> Prepare a test piece 52, which is a rectangle with the absorption axis of the polarizing element as its long side, and the polarizing film 51 is processed into a rectangle with a width of 10 mm and a length of 50 mm. Next, one end 53a of the test piece 52 along its long side is fixed to the surface of the evaluation sheet 54 (see Figure 3(a)). To ensure that the other end 53b of the test piece 52 curls upwards due to heating, the fixing is performed on the upper surface of the test piece 52 during fixing. Adhesive tape 56 can be used for fixing, but the fixing method is not limited as long as end 53a does not peel off from the evaluation sheet 54 during the test. An example of adhesive tape 56 is polyimide tape. Next, the entire assembly is heated to 105°C for 12 hours, causing the test piece 52 to curl from the other end 53b along its long side. The inner diameter of the cylindrical portion 55 formed by the curling of the test piece 52 is determined as the curling diameter (see Figure 3(b)).

The degree of curling of the test piece 52 may vary depending on the inherent thermal properties of the polarizing film 51. The inherent thermal properties of the polarizing film 51 vary depending on the layer structure of the polarizing film 51, the composition, thickness, and arrangement of each layer of the polarizing film 51. One example of the inherent thermal properties is the bending moment M during heating, as described below.

The evaluation sheet 54 can be a sheet that, even when heated to 105°C for 12 hours, will not undergo bending or other deformation that would hinder the evaluation of the curl diameter. One example of the evaluation sheet 54 is a 5mm thick polystyrene sheet.

The absolute value of the bending moment M of the polarizing film can be less than 1× ^10⁹ , or less than 1× ^10⁸ , 5× ^10⁷ , 1× ^10⁷ , 8× ^10⁶ , 5× ^10⁶ , 4× ^10⁶ , and even less than 3× ^10⁶ . The use of polarizing films with small bending moments M is suitable, for example, when forming an antistatic layer 2 on a polarizing film, as it helps to suppress curling while increasing the heating temperature during formation.

The calculation method for the bending moment M will be explained with reference to Figure 4. Figure 4 is a cross-sectional view showing an example of the polarizing film 51. The polarizing film 51 in Figure 4 has a structure in which the polarizing element 61 is clamped by a pair of transparent protective films 62 and 63. The polarizing element 61 is made of PVA and has a thickness of 22µm. The transparent protective film 62 is made of triacetate cellulose (TAC) and has a thickness of 40µm. The transparent protective film 63 is made of acrylic resin and has a thickness of 20µm. Symbol 51C is an imaginary surface located at the center in the thickness direction of the polarizing film 51 (hereinafter referred to as center surface 51C). Symbols 61C, 62C, and 63C are respectively imaginary surfaces located at the center in the thickness direction of each layer (hereinafter referred to as center surfaces 61C, 62C, and 63C).

For each layer of the polarizing film 51, the expansion forces P ( _P61 , _P62 , _P63 ) during heating can be determined. The expansion force P of the layers other than the polarizing element is defined by the formula: EtαΔT. The expansion force P of the polarizing element is defined by: EtβΔT. E is the storage elastic modulus E of each layer at 23°C (unit: MPa), t is the thickness of each layer (unit: µm), α is the coefficient of thermal expansion of each layer (unit: /°C), ΔT is the temperature difference from the room temperature (23°C) during heating (unit:°C), and β is the dimensional change rate of the polarizing element due to heating (105°C and 500 hours) (unit: %). The storage modulus of elasticity E is a value obtained through a tensile test. The tensile test is performed on a dumbbell-shaped test piece at a tensile speed of 300 mm/min. The value of E for the polarizer 61 is set to the slow axis direction. The coefficient of thermal expansion α is a value obtained through thermomechanical analysis (TMA). TMA is performed with the measurement temperature set to -40~85℃, the sample size set to 5 mm wide, and the fixture spacing set to 20 mm. ΔT is set to 67 (=90-23)℃, taking into account the heating temperature during the formation of the antistatic layer 2. In addition, the polarizer 61 usually shrinks in the slow axis direction due to heating, so β and the expansion force P ₆₁ are usually negative values.

The dimensional change rate β of the polarizer can be determined by the dimensional change of the test piece before and after a heating test. This heating test involves processing the polarizer with the adhesive layer into a 10cm × 10cm test piece, attaching the test piece to a glass plate, and placing it in an oven maintained at 105°C for 500 hours. However, the direction of one side of the test piece is set to the absorption axis direction of the polarizer. The dimensional change rate β is calculated using the formula: Dimensional Change Rate β = (W _min - 10) / 10 × 100 (%). W _min is the length of the shortest side of the test piece after the heating test. The polarizer with the adhesive layer can be prepared as follows. * In a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet, and cooler, a monomer mixture containing 99 parts by weight of butyl acrylate and 1 part by weight of 4-hydroxybutyl acrylate was added. Next, relative to 100 parts by weight of the monomer mixture, 0.1 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-azobisisobutyronitrile) as a polymerization initiator and 100 parts by weight of ethyl acetate were added. Then, while slowly stirring the mixture, nitrogen was introduced for nitrogen replacement, and the liquid temperature in the flask was maintained at approximately 55°C for 8 hours to allow the polymerization reaction to proceed, thus preparing a solution of the acrylic polymer. The weight-average molecular weight of the acrylic polymer was set to approximately 1.8 million. Next, relative to 100 parts by weight of the solid component of the prepared solution, 0.03 parts by weight of trihydroxypropyl propane/diisocyanate adduct (e.g., TAKENATE D110N manufactured by Tosoh), 0.3 parts by weight of benzoyl peroxide, and 0.2 parts by weight of epoxy-containing silane coupling agent (e.g., KBM-403 manufactured by Shin-Etsu Chemical Industry Co., Ltd.) were mixed in to prepare an adhesive composition. Then, the prepared adhesive composition coating was dried at 155°C for 1 minute to prepare an adhesive layer with a thickness of 20µm. The polarizing element was then bonded to the prepared adhesive layer to obtain a polarizing film with the adhesive layer attached.

Furthermore, for each layer contained in the polarizing film 51, the distances d ( _d61 , _d62 , _d63 ) from the center plane 51C of the polarizing film 51 to the center planes 61C, 62C, and 63C of each layer can be determined. However, the unit of distance d is set to µm, and the direction 65 from one principal plane 64A of the polarizing film 51 to the other principal plane 64B is set as negative to define the sign of distance d. In the example of Figure 4, distance _d62 is negative, and distances _d61 and _d63 are positive. The bending moment M can be determined as the sum of the products of the expansion forces P and d of each layer constituting the polarizing film 51. In the example of Figure 4, the bending moment M = P ₆₁ × d ₆₁ + P ₆₂ × d ₆₂ + P ₆₃ × d ₆₃ .

The polarizing film 51 typically has a multi-layered structure containing polarizing elements. The bending moment M can be calculated similarly even when the layered structure of the polarizing film 51 or the materials constituting each layer are different. Furthermore, the expansion force P generated in the hard coating layer is usually very small and can therefore be ignored in the calculation of the bending moment M.

<1-3-b. Phase Refraction Thin Film> Regarding phase retardation thin films, those obtained by stretching polymer films or those for which liquid crystal materials have been oriented and immobilized can be used. Phase retardation thin films, for example, have birefringence in the in-plane and/or thickness directions.

Regarding phase retardation films, examples include anti-reflection phase retardation films (see Japanese Patent Application Publication No. 2012-133303 [0221], [0222], [0228]), view angle compensation phase retardation films (see Japanese Patent Application Publication No. 2012-133303 [0225], [0226]), and view angle compensation tilt-oriented phase retardation films (see Japanese Patent Application Publication No. 2012-133303 [0227]).

Regarding phase retardation films, if they substantially possess the aforementioned functions, there are no particular restrictions on aspects such as phase difference value, configuration angle, 3D birefringence, single layer or multiple layers, and known phase retardation films can be used.

The thickness of the phase retardation film should preferably be less than 20µm, more preferably less than 10µm, even more preferably 1~9µm, and especially preferably 3~8µm.

Phase retardation films, for example, are composed of two layers of liquid crystal material, namely a 1/4 wavelength plate and a 1/2 wavelength plate, which are oriented and immobilized.

≪1-4. Method for Manufacturing Optical Multilayers≫ The optical multilayer 10 can be manufactured, for example, by: manufacturing a first multilayer L1 consisting of an optical thin film 3 and an antistatic layer 2; manufacturing a second multilayer L2 consisting of a substrate and an adhesive sheet 1; and bonding the adhesive sheet 1 of the second multilayer L2 to the antistatic layer 2 of the first multilayer L1. However, the method for manufacturing the optical multilayer 10 is not limited to this example.

<1-4-a. Preparation of Antistatic Layer 2 and First Deposition L1> First, a solution or dispersion of conductive particles is prepared. Examples of solvents for the solution or dispersion are water and organic solvents. The organic solvent may also be water-soluble. The solvent may be a single solvent or a mixture containing two or more solvents. Examples of mixed solvents are solvents containing water and water-soluble organic solvents. Examples of water-soluble organic solvents include: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, dibutanol, tert-butanol, n-pentanol, isopentanol, dipentanol, tert-pentanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, etc. Water-soluble organic solvents may also be isopropanol (IPA). According to the inventors' review, combining conductive particles with a single solvent helps to suppress changes in the state of the conductive particles in the antistatic layer 2 before and after the DIN test. Water is the preferred single solvent.

Next, a solution or dispersion of conductive particles is applied as a coating liquid to the surface of the optical thin film 3. By drying the resulting coating film, an antistatic layer 2 is formed on the optical thin film 3. This yields a first laminate L1 consisting of the optical thin film 3 and the antistatic layer 2. Heating can also be used during drying. The drying temperature when heating is used can be, for example, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, 90°C or higher, 95°C or higher, 100°C or higher, 110°C or higher, 120°C or higher, and even 130°C or higher. The upper limit of the drying temperature is, for example, 160°C or lower. Based on the inventors' review, setting a drying temperature above 70°C, preferably above 80°C, and more preferably above 90°C, can help suppress changes in the state of conductive particles in the antistatic layer 2 before and after the DIN test. On the other hand, if the drying temperature during the formation of the antistatic layer 2 becomes too high, the optical laminate 2 may easily curl. To suppress curling, an upper limit for the drying temperature can also be appropriately set. This may vary depending on the composition of the optical thin film 3, but the upper limit is, for example, below 160°C, or below 150°C, below 140°C, below 130°C, below 130°C, below 125°C, below 120°C, below 115°C, and even below 110°C.

With regard to the fabrication of the ideal antistatic layer 2, this embodiment discloses the manufacturing method shown below. That is, the manufacturing method of the antistatic layer 2 in this embodiment includes the following steps: drying a coating film containing conductive particles and a single solvent, such as a solution or dispersion, to form the antistatic layer 2. The ideal state of the conductive particles and the single solvent is, for example, as described above. The coating film can be formed on the surface of a substrate, for example. The substrate can be, for example, a release film. The antistatic layer 2 formed on the release film can, for example, be transferred onto an optical film. The substrate can also be an optical film. The coating liquid can also contain other materials besides conductive particles, such as binder resins. The ideal state of the binder resin is as described above. The coating liquid may contain a leveling agent. However, the leveling agent content in the coating liquid should be low, as exemplified in the description of antistatic layer 2. The coating liquid may also be substantially free of leveling agent. The ideal drying temperature of the coating film is as described above. The drying temperature may also be above 70°C and below 130°C.

Furthermore, the manufacturing method of the antistatic layer 2 of this embodiment includes the following steps: drying a coating film containing a coating liquid with conductive particles at a temperature above 70°C and below 130°C to form the antistatic layer 2. The ideal drying temperature of the coating film is as described above. An example of the ideal state of the conductive particles is as described above. The coating film may be formed on the surface of a substrate, for example. The substrate may be, for example, a release film. The antistatic layer 2 formed on the release film may be transferred, for example, onto an optical film. The substrate may also be an optical film. The coating liquid may also contain other materials besides conductive particles, such as binder resin. An example of the ideal state of the binder resin is as described above. The coating liquid may contain a leveling agent. However, the content of leveling agent in the coating solution should be low, as exemplified in the previous description of antistatic layer 2. The coating solution may also be substantially free of leveling agent. The solvent contained in the coating solution may also be a single solvent. An ideal example of a single solvent is as described above.

The method for manufacturing the optical laminate of this embodiment is a method for manufacturing an optical laminate having an adhesive sheet, an antistatic layer and an optical thin film. The manufacturing method includes forming the antistatic layer by the manufacturing method of the antistatic layer 2 of this embodiment.

<1-4-b. Method for manufacturing the second laminate L2> The adhesive sheet 1 is formed from an adhesive composition (I). The adhesive sheet 1 may contain, for example, a crosslinked polymer of (meth)acrylate. The adhesive sheet 1 is formed from the adhesive composition (I) by the following method.

The adhesive sheet 1 can be formed, for example, by applying an adhesive composition (I) onto a substrate to form a coating film; and drying the resulting coating film. In this way, a second laminate L2 consisting of a substrate and the adhesive sheet 1 can be obtained.

Regarding the substrate, a release film, for example, can be used. The adhesive sheet 1 formed on the release film can, for example, be transferred onto an optical film. The substrate can also be an optical film.

The release film can be used as a peeling film after the adhesive sheet 1 is transferred to the antistatic layer 2, until the adhesive sheet 1 is ready for actual use. At this time, the process can be simplified.

Regarding the constituent materials of release films, examples include: plastic films; porous materials such as paper, cloth, and non-woven fabrics; suitable sheet materials such as meshes, foam sheets, metal foils, and laminates thereof. From the perspective of excellent surface smoothness, plastic films are suitable for use.

Regarding plastic films, there are no specific limitations, but 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.

The thickness of the release film is typically 5–200 µm, preferably around 5–100 µm. The release film undergoes release treatment using release agents such as polysiloxane, fluorine, or long-chain alkyl compounds. The release film can also undergo release treatment or antifouling treatment using fatty acid amide-based release agents, silica powder, etc., or various antistatic treatments such as coating, kneading, or vapor deposition.

A solution containing adhesive component (I) (adhesive solution) can also be applied to the substrate. The solid content concentration of the adhesive solution is, for example, 5-50% by weight, preferably 10-40% by weight. The adhesive solution can also be prepared by appropriately adding the same or different solvents as the polymerization solvent to the adhesive component (I) depending on the polymerization form of the (meth)acrylic polymer (A).

Various methods can be used to apply the adhesive composition (I) to the substrate, such as roller coating, contact roller coating, gravure coating, reverse coating, roller brushing, spraying, dip roller coating, rod coating, scraper coating, air knife coating, curtain coating, lip coating, and extrusion coating using a molding machine. The amount of adhesive composition (I) applied can be appropriately adjusted according to the thickness of the target adhesive sheet 1.

The coating film is hardened by drying, forming adhesive sheet 1. The drying temperature of the coating film is, for example, below 130°C, preferably below 125°C, more preferably below 120°C, even more preferably below 110°C, and especially preferably below 100°C. The drying temperature of the coating film can be above 60°C or above 80°C. Regarding drying temperatures above 60°C, for example, by ensuring the smooth reaction of the isocyanate-based crosslinker, the cohesive force of adhesive sheet 1 can be improved. Regarding drying temperatures below 130°C, for example, by appropriately adjusting the reaction rate of the isocyanate-based crosslinker, the transparency of adhesive sheet 1 can be improved.

The drying time of the coating film can be adjusted appropriately according to the composition of the adhesive component (I), preferably 30 seconds to 300 seconds, more preferably 40 seconds to 240 seconds, and especially preferably 60 seconds to 180 seconds.

The thickness of the adhesive sheet 1 is not particularly limited and can be 2~150µm, 2~100µm, or 5~50µm. Appropriately adjusting the thickness of the adhesive sheet 1 can help improve the adhesion between the adhesive sheet 1 and the antistatic layer 2. Furthermore, appropriately adjusting the thickness of the adhesive sheet 1 can help prevent the adhesive sheet 1 from peeling off from the glass, image display device, or other adhered objects.

<1-4-c. Bonding of the first laminate L1 and the second laminate L2> Next, the adhesive sheet 1 of the second laminate L2 is bonded to the antistatic layer 2 of the first laminate L1. Thereby, a laminate consisting of an optical film 3, an antistatic layer 2, an adhesive sheet 1, and a substrate can be obtained.

≪1-5. Another Embodiment≫ Figure 5 is a cross-sectional view, schematically showing another example of the optical laminate of this embodiment. The optical laminate 10 (10B) of Figure 5 has a laminated structure in which a peelable backing material 4, an adhesive sheet 1, an antistatic layer 2, and an optical thin film 3 are sequentially laminated. The optical laminate 10B can be used, for example, attached to an image display unit after the backing material 4 is peeled off.

Regarding the materials used to peel off the lining 4, examples include: plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film; porous materials such as paper, cloth, and non-woven fabric; suitable sheets such as meshes, foam sheets, metal foils, and laminates thereof. From the perspective of excellent surface smoothness, plastic films are suitable for use.

Regarding plastic films, there are no particular limitations if they are films that can protect the adhesive sheet 1. 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-ethyl acetate copolymer film, etc.

The thickness of the peeling lining 4 is typically 5~200µm, preferably around 5~100µm. The peeling lining 4 can also undergo various treatments as needed, such as mold release treatment, anti-fouling treatment, and antistatic treatment. Mold release treatment and anti-fouling treatment can utilize various mold release agents such as polysiloxane, fluorine, long-chain alkyl, and fatty acid amide-based agents, or particles such as silica powder. Antistatic treatment can be of any type: coating, kneading, or vapor deposition. Applying a peeling treatment to the surface of the peeling lining 4 is particularly suitable for improving the peelability of the adhesive sheet 1.

The release film used to form the adhesive sheet 1 can also be used as the peeling liner 4.

The optical multilayer of this embodiment may also have other layers and/or thin films besides those mentioned above.

The optical laminate of this embodiment can be circulated and stored, for example, in the form of a wound body formed by winding a strip of optical laminate, or in the form of a monolithic optical laminate. The optical laminate of this embodiment is suitable for use in image display devices, especially automotive displays, in environments where static electricity is particularly prone to occur. Examples of automotive displays include car navigation panels, instrument panels, and mirror displays. An instrument panel displays information such as vehicle speed or engine RPM.

≪≪2. Image Display Panel≫≫ FIG6 shows an example of an image display panel according to an embodiment of the present invention. The image display panel 11 (11A) of FIG6 has an optical laminate 10A and further has an image display unit 30A. The optical laminate 10A is attached to the image display unit 30A by means of an adhesive sheet 1.

The image display unit 30A includes an image forming layer 32, a first transparent substrate 31, and a second transparent substrate 33. The image forming layer 32 is disposed between the first transparent substrate 31 and the second transparent substrate 33, and is in contact with both the first transparent substrate 31 and the second transparent substrate 33. The adhesive sheet 1 is in contact with the first transparent substrate 31.

The image forming layer 32 may be, for example, a liquid crystal layer containing liquid crystal molecules aligned along the plane in the absence of an electric field. The liquid crystal layer containing these liquid crystal molecules is suitable for IPS (In-Plane Switching) technology. However, the liquid crystal layer can also be used for TN (Twisted Nematic), STN (Super Twisted Nematic), π-type, VA (Vertical Alignment), etc. The image forming layer 32 may also be an EL (Elastic Elastic Gravity) emitting layer.

The thickness of the image forming layer 32 is, for example, 1.5µm to 4µm.

The materials used for the first transparent substrate 31 and the second transparent substrate 33 may include, for example, glass and polymers. Examples of polymers constituting the transparent substrates include polyethylene terephthalate, polycyclic aromatic hydrocarbons, and polycarbonate. The thickness of the transparent substrate made of glass may be, for example, 0.1 mm to 1 mm. The thickness of the transparent substrate made of polymer may be, for example, 10 µm to 200 µm.

The image display unit 30A may also include layers other than the image forming layer 32, the first transparent substrate 31, and the second transparent substrate 33. Examples of these other layers include, for instance, a color filter, an easy-adhesion layer, and a hard coating layer. The color filter, for example, is disposed on the viewing side of the image forming layer 32, preferably between the first transparent substrate 31 and the adhesive sheet 1. The easy-adhesion layer and the hard coating layer, for example, are disposed on the surfaces of the first transparent substrate 31 and/or the second transparent substrate 33.

The image display panel 11A may also include other components besides the optical laminate 10A and the image display unit 30A. For example, the image display panel 11A may also include a conductive structure (not shown) electrically connected to the side of the optical laminate 10A. By connecting the conductive structure to ground, it is easy to suppress the optical laminate 10A from becoming charged due to electrostatics. The conductive structure may cover the entire side of the optical laminate 10A or only partially cover the side of the optical laminate 10A. The ratio of the area covered by the conductive structure on the side of the optical laminate 10A to the total area of the side of the optical laminate 10A is, for example, 1% or more, preferably 3% or more.

For example, the materials used in the conductive structure include: conductive pastes made of metals such as silver and gold; conductive adhesives; and other conductive materials. The conductive structure can also be a wiring extending from the side of the optical laminate 10A.

The image display panel 11A may also be equipped with other optical films besides optical film 3. Examples of other optical films include polarizing films, reflective films, anti-transmission films, viewing angle compensation films, and brightness enhancement films, which can be used in image display devices. The image display panel 11A may also have one or more other optical films.

When the other optical thin film is a polarizing thin film, it can also be bonded to the second transparent substrate 33 of the image display unit 30A. The polarizing thin film, as another optical thin film, can also have the same structure as the polarizing thin film belonging to optical thin film 3. In the polarizing thin film as optical thin film 3 and the polarizing thin film as another optical thin film, the transmission axis (or absorption axis) of the polarizing element can also be orthogonal to each other. When bonding with the second transparent substrate 33, an adhesive sheet can be used. The adhesive sheet can also be adhesive sheet 1. The thickness of the adhesive sheet used to bond with the second transparent substrate 33 is, for example, 1~100µm, 2~50µm, 2~40µm, or even 5~35µm.

Figure 7 shows another example of the image display panel of this embodiment. The image display panel 11 (11B) of Figure 7 has the same configuration as the image display panel 11A, except that it is further provided with a conductive layer 40 disposed between the optical laminate 10A and the image display unit 30A. However, the image display panel of this embodiment may also be without the conductive layer 40. The absence of the conductive layer 40 helps to suppress the reflectivity of the image display panel, in other words, it helps to improve the visibility of the image display device. In the image display panel 11A without the conductive layer 40, a conductive portion (the aforementioned conductive structure) adjacent to the adhesive sheet 1 is preferably provided. The conductive portion can use, for example, conductive silver paste.

The conductive layer 40 may include a conductive agent, for example. The conductive agent may be a known material such as a metal oxide or a conductive polymer. The thickness of the conductive layer 40 may be, for example, 5 nm to 180 nm. The surface resistivity of the conductive layer 40 may be, for example, 1.0 × ^10⁶ Ω/□ to 1.0 × ^10¹⁰ Ω/□, preferably 1.0 × ^10⁷ Ω/□ to 1.0 × ^10⁹ Ω/□.

The image display panel of this embodiment can also have built-in touch sensing functionality. Figure 8 shows an example of an image display panel with built-in touch sensing functionality. The image display panel 11 (11C) in Figure 8 has the same structure as the image display panel 11A, except that the image display unit 30B includes a touch sensing electrode 35. The touch sensing electrode 35 is disposed between the first transparent substrate 31 and the second transparent substrate 33. The touch sensing electrode 35 has the functions of a touch sensor and touch driving. The image display panel 11C is a so-called built-in image display panel, and the image display unit 30B is a so-called built-in image display unit. However, the touch sensing electrode 35 can also be positioned on the viewing side further away from the first transparent substrate 31. In other words, the image display panel 11C can be a so-called top-mounted image display panel, and the image display unit 30B can also be a so-called top-mounted image display unit.

The touch sensing electrode unit 35 includes a touch sensor electrode 36 and a touch driving electrode 37. The touch sensor electrode 36 refers to the touch detection (receiving) electrode. The touch sensor electrode 36 and the touch driving electrode 37 can each be formed independently using various patterns. For example, when the image display unit 30B is flat, the touch sensor electrode 36 and the touch driving electrode 37 can each be independently arranged in the X-axis direction and the Y-axis direction, forming patterns that intersect at right angles. In Figure 8, in the touch sensing electrode section 35, the touch sensor electrode 36 is positioned further towards the viewing side than the touch driver electrode 37. The touch driver electrode 37 can also be positioned further towards the viewing side than the touch sensor electrode 36. In the touch sensing electrode section 35, the touch sensor electrode 36 and the touch driver electrode 37 can also be integrated.

The touch sensing electrode 35 in Figure 8 is disposed between the image forming layer 32 and the first transparent substrate 31 (more towards the viewing side than the image forming layer 32). However, the touch sensing electrode 35 can also be disposed between the image forming layer 32 and the second transparent substrate 33 (more towards the lighting system side than the image forming layer 32).

In the touch sensing electrode section 35, the touch sensor electrode 36 and the touch driving electrode 37 may not be connected to each other. For example, the touch sensor electrode 36 may be disposed between the image forming layer 32 and the first transparent substrate 31, and the touch driving electrode 37 may be disposed between the image forming layer 32 and the second transparent substrate 33.

The driving electrode in the touch sensing electrode section 35 (touch driving electrode 37, or an electrode formed by integrating touch sensor electrode 36 and touch driving electrode 37) can also serve as the common electrode for controlling the image forming layer 32.

The touch sensor electrode 36 (capacitive sensor), touch drive electrode 37, or an integrated electrode constituting the touch sensing electrode portion 35 function as a transparent conductive layer. The material of the transparent conductive layer is not particularly limited, and can include metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, and tungsten, as well as their alloys. The material of the transparent conductive layer can also be oxides of metals such as indium, tin, zinc, gallium, antimony, zirconium, and cadmium. Specifically, oxides include indium oxide, tin oxide, titanium oxide, cadmium oxide, and mixtures thereof. The transparent conductive layer can also be made of metal compounds such as copper iodide. The preferred materials for the transparent conductive layer are indium oxide (ITO) containing tin oxide or tin oxide containing antimony, with ITO being particularly preferred. When the transparent conductive layer is made of ITO, the indium oxide content should be 80-99% by weight, and the tin oxide content should be 1-20% by weight.

The electrodes constituting the touch sensing electrode portion 35 (touch sensor electrode 36, touch drive electrode 37, or electrodes integrated therein) can be formed between the first transparent substrate 31 and the second transparent substrate 33 using conventional methods to form a transparent electrode pattern. The transparent electrode pattern is, for example, electrically connected to a wire wound formed at the end of the transparent substrate. The wire wound is, for example, connected to a controller IC. Regarding the shape of the transparent electrode pattern, any shape such as comb-shaped, striped, or diamond-shaped can be used depending on the application. The thickness of the transparent electrode pattern is, for example, 10nm to 100nm. The width of the transparent electrode pattern is, for example, 0.1mm to 5mm.

≪≪3. Image Display Device≫≫ An image display device of the present invention, for example, includes an image display panel 11A and a lighting system. Alternatively, an image display panel 11B or an image display panel 11C may be used instead of the image display panel 11A. In the image display device, the image display panel 11A is, for example, positioned further from the viewing side than the lighting system. The lighting system, for example, has a backlight or a reflector that illuminates the image display panel 11A.

The image display device of this embodiment can be an organic EL display or a liquid crystal display. However, the image display device is not limited to this example. The image display device can also be an electroluminescent (EL) display, a plasma display (PD), a field emission display (FED), etc. The image display device can be used for home appliances, automotive applications, public information displays (PIDs), etc., and can also be an automotive display.

Examples The present invention will be further described in detail below by way of examples. The present invention is not limited to the examples shown below.

[Preparation of the first layer L1 consisting of an antistatic layer and a polarizing film] <Preparation of the coating solution for forming the antistatic layer> (Coating solution A1) Coating solution A1 with a solid content of 0.5% by weight was prepared by mixing 25 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7) and 75 parts by weight of water. The binder resin is acrylic and has a Tg of 50°C. The solid content ratio of CNTs to binder resin in the above solution is 1:99 (by weight). The length of the CNTs is in the range of 5µm to 200µm, and the diameter of the CNTs is in the range of 2nm to 8nm.

(Applying solution A2) Applying solution A2 with a solid content of 0.5% by weight is prepared by mixing 25 parts by weight of a solution containing CNT and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7) and 75 parts by weight of isopropyl alcohol (IPA).

(Applying solution A3) Applying solution A3 with a solid content of 0.5% by weight is prepared by mixing 25 parts by weight of a solution containing CNT and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7), 37.5 parts by weight of water and 37.5 parts by weight of IPA.

(Coating Solution A4) Coating solution A4 with a solid content of 0.5% by weight was prepared by mixing 25 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7), 2.6 parts by weight of EMULMIN 240 (1% aqueous solution) manufactured by Sanyo Chemical Industries Co., Ltd. as a polyether leveling agent, and 72.3 parts by weight of water. The solid content ratio of CNTs, binder resin and leveling agent in the prepared coating solution A4 is 1:94:5 (by weight).

(Coating Solution A5) Coating solution A5 with a solid content of 0.5% by weight was prepared by mixing 25 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7), 9.0 parts by weight of EMULMIN 240 (1% aqueous solution) manufactured by Sanyo Chemical Industries Co., Ltd. as a polyether leveling agent, and 66 parts by weight of water. The solid content ratio of CNTs, binder resin and leveling agent in the prepared coating solution A5 is 1:84:15 (by weight).

(Coating Solution A6) Coating solution A6 with a solid content of 0.5% by weight is prepared by mixing 15.2 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-3-3), 9.0 parts by weight of EMULMIN 240 (1% aqueous solution) manufactured by Sanyo Chemical Industries Co., Ltd. as a polyether leveling agent, and 75.8 parts by weight of water. The binder resin is polyurethane-based and has a Tg of -15°C. The length of the CNTs is in the range of 5µm to 200µm, and the diameter of the CNTs is in the range of 2nm to 8nm. The solid components of CNT, binder resin and leveling agent in the prepared coating liquid A6 are in the ratio of 1:84:15 (by weight).

(Coating Solution A7) 0.08 parts by weight of CNTs (manufactured by Zeon Nano Technology, ZEONANO SG101) with an average length of 300µm and a diameter of approximately 4nm, 0.7 parts by weight of dispersant (manufactured by BASF, product name: Pluronic F-108, HLB: 24 or higher), 30 parts by weight of ethanol, and 70 parts by weight of pure water were placed in a glass beaker and dispersed using an ultrasonic homogenizer at 50W and 30kHz for 30 minutes to obtain a CNT dispersion with a solid content of 1.0% by weight. Next, the obtained CNT dispersion, binder resin, and leveling agent were mixed in a solid content ratio of 8:77:15 (by weight), and the mixture was diluted with pure water to prepare coating solution A7 with a solid content of 2% by weight. The binder resin used is SUPERFLEX 650 (polyurethane, 26% by weight, Tg -15℃) manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd. The leveling agent used is EMULMIN 240 (1% aqueous solution) manufactured by Sanyo Chemical Co., Ltd., a polyether-based leveling agent.

(Applying Solution A8) Applying solution A8 is prepared by mixing 25 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7), 0.47 parts by weight of a solution containing a different binder resin (manufactured by Nagase ChemteX Co., product name: TS066-1-5), and 74.5 parts by weight of water, resulting in a solid content concentration of 0.5% by weight. The binder resin contained in TS066-1-5 is a polyurethane-based resin with a Tg of -15°C. The solid component ratio of CNT, binder resin (Tg=50℃) and binder resin (Tg=-15℃) in the prepared coating solution A8 is 1:94:5 (by weight).

(Coating Solution A9) Coating solution A9 with a solid content of 0.5% by weight is prepared by mixing 25 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-11-7), 2.3 parts by weight of a solution containing a different binder resin (manufactured by Nagase ChemteX Co., product name: TS066-1-5), and 72.6 parts by weight of water. The solid content ratio of CNTs, binder resin (Tg=50℃), and binder resin (Tg=-15℃) in the prepared coating solution A9 is 1:79:20 (by weight).

(Coating Solution A10) Coating solution A10 with a solid content of 0.5% by weight was prepared by mixing 15.2 parts by weight of a solution containing CNTs and binder resin (manufactured by Nagase ChemteX Co., product name: TS066-3-3) and 84.8 parts by weight of water. The solid content ratio of CNTs to binder resin in the prepared coating solution A10 is 1:99 (by weight).

The various topical solutions are summarized in Table 1.

[Table 1]

<Preparation of Polarizing Film> (Preparation of Protective Film A with Hard Coating) Prepare a resin solution (manufactured by DIC Corporation, trade name: UNIDIC 17-806, solid content concentration: 80%) containing a UV-curable resin monomer or oligomer with carbamate acrylate as the main component dissolved in butyl acetate. Next, relative to 100 parts by weight of the solid content of the resin solution, add 5 parts by weight of photopolymerization initiator (manufactured by BASF Corporation, trade name: IRGACURE907) and 0.1 parts by weight of leveling agent (manufactured by DIC Corporation, trade name: GRANDIC PC4100). Next, cyclopentanone and propylene glycol monomethyl ether were added to the resin solution at a weight ratio of 45:55 to adjust the solid content of the resin solution to 36% by weight, thus preparing a hard coating forming material. The prepared forming material was then applied to a transparent protective film containing triacetate cellulose (TAC film manufactured by Konica Minolta, trade name "KC4UY", thickness 40µm) to form a coating. The thickness of the coating was adjusted so that the hard coating obtained by curing the forming material would be 7µm. The coating was then dried at 90°C for 1 minute and irradiated with ultraviolet light at a cumulative intensity of 300mJ/ ^cm² using a high-pressure mercury lamp. This allows the coating to harden, resulting in a protective film A (47µm thick) with a hardened coating (HC).

(Fabrication of Polarizing Component A) A polyvinyl alcohol (PVA) film with an average degree of polymerization of 2400, a saponification degree of 99.9 moles, and a thickness of 45 µm is immersed in a swelling bath (water bath) at 20°C for 30 seconds to swell, while simultaneously extending it 2.2 times in the conveying direction (swelling step). Next, the film is immersed in a dyeing bath at 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a 1:7 weight ratio relative to 100 parts by weight of water) for 30 seconds while adjusting the concentration to achieve an iodine concentration of 3.1% by weight in the final polarizing component, while simultaneously extending it 3.3 times in the conveying direction based on the original PVA film (a PVA film that has not been extended in the conveying direction) (dyeing step). The extension is performed using rollers with different peripheral speeds. Next, the dyed PVA film was immersed in a crosslinking bath at 40°C (an aqueous solution of boric acid, potassium iodide, and zinc sulfate at 3.5 wt%, 3.0 wt%, and 3.6 wt%) for 28 seconds, and then stretched 3.6 times in the transport direction based on the original PVA film (crosslinking step). Then, the crosslinked PVA film was immersed in a stretching bath at 64°C (an aqueous solution of boric acid, potassium iodide, and zinc sulfate at 5.0 wt%) for 60 seconds, and then stretched 6.0 times in the transport direction based on the original PVA film (stretching step). Next, the PVA film was immersed in a 27°C washing bath (an aqueous solution with a potassium iodide concentration of 2.3% by weight) for 10 seconds (washing step), and then dried at 40°C for 30 seconds to obtain a polarizing element A with a thickness of 18µm.

(Fabrication of Polarizing Component B) Using rollers with different periodic speed ratios, an 80µm thick PVA film was dyed in an iodine aqueous solution (0.3 wt%) at 30°C for 1 minute while being stretched 3.0 times in the conveying direction. Next, it was immersed in an aqueous solution at 60°C with a boric acid concentration of 4% wt% and a potassium iodide concentration of 10% wt% for 0.5 minutes, and stretched 6.0 times in the conveying direction based on the original PVA film. Then, it was washed by immersion in an aqueous solution at 30°C with a potassium iodide concentration of 1.5% wt% for 10 seconds, and dried at 50°C for 4 minutes to obtain a 28µm thick polarizing component B.

(Fabrication of Polarizing Component C) Using rollers with different periodic speed ratios, a 60µm thick PVA film was dyed in an iodine aqueous solution (0.3 wt%) at 30°C for 1 minute while being stretched 3.0 times in the conveying direction. Next, it was immersed in an aqueous solution at 60°C with a boric acid concentration of 4% wt% and a potassium iodide concentration of 10% wt% for 0.5 minutes, and stretched 6.0 times in the conveying direction using the original PVA film as a reference. Then, it was washed by immersion in an aqueous solution at 30°C with a potassium iodide concentration of 1.5% wt% for 10 seconds, and dried at 50°C for 4 minutes to obtain a 22µm thick polarizing component C.

(Preparation of Phase Difference Thin Film A) In a high-pressure reactor equipped with a stirrer, coolant, nitrogen inlet pipe, and thermometer, 48 parts by weight of hydroxypropyl methylcellulose (Shin-Etsu Chemical, METOLOSE 60SH-50), 15601 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate, 240 parts by weight of methyl 3-ethyl-3-oxocyclobutane acrylate, and 45 parts by weight of trimethylolpropene peroxide (tributyl acetate) as a polymerization initiator were placed. After nitrogen foaming for 1 hour, the mixture was stirred and maintained at 49°C for 24 hours to allow free radical suspension polymerization. Subsequently, after cooling to room temperature, the fumarate-based resin particles generated by polymerization were centrifuged and separated. The obtained particles were washed twice with distilled water and twice with methanol, followed by depressurized drying. Next, the particles were dissolved in a toluene-methyl ethyl ketone mixed solution (50% by weight toluene/50% by weight methyl ethyl ketone) to prepare a solution with a concentration of 20% by weight. Furthermore, 5 parts by weight of tributyl trimellitate were added as a plasticizer to 100 parts by weight of fumarate-based resin to prepare a coating (dope). The prepared coating was then applied to a support film to achieve a dried film thickness of 6.3 µm and dried at 140°C. The support system used a biaxially stretched polyester (polyethylene terephthalate/polyethylene terephthalate copolymer) film (75 µm thick, heat-treated). Next, the laminate obtained in the above manner is uniaxially stretched at a temperature of 140°C. The support film is peeled off from the stretched laminate to obtain the phase difference film A (thickness 6µm, Re(550) 35nm).

(Preparation of Polarizing Film A) Using a roller laminator, a protective film A with HC is laminated onto one main surface of the polarizer A, and a phase retardation film B (ZEON ZT12, 17µm thick cycloolefin film, manufactured in Japan) is laminated onto the other main surface. The lamination is performed using an adhesive at 30°C. The adhesive is an aqueous solution containing acetylated PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetylation 5 mol%) and hydroxymethyl melamine in a 3:1 weight ratio. After drying the entire assembly in an oven, a photocurable adhesive composition is applied to the phase retardation film B side of the resulting laminated film to a thickness of 1µm. The application was performed using an MCD coating machine (manufactured by Fuji Machinery). The composition of the agent is as described below. • 20 parts by weight of ε-caprolactone modified with hydroxyalkyl unsaturated fatty acids (DAICL, Placcel FA1DDM) • 20 parts by weight of acrylamide (Kojin) • 3 parts by weight of diethylacrylamide (KJ Chemicals Corporation, DEAA) • 6.7 parts by weight of lauryl acrylate (Kyoei Chemicals, LIGHT ACRYLATE LA) • 27 parts by weight of isostearyl acrylate (Osaka Organic Chemical Industry, ISTA) • 10 parts by weight of 1,9-nonanediol diacrylate (Kyoei Chemicals, LIGHT ACRYLATE 1,9ND-A) • 13.3 parts by weight of 34/66 molar ratio copolymer oligomer of butyl acrylate and methacrylate (Toa Synthetic, ARUFON UP-1190, molecular weight 1700) • Omnirad as a photoinitiator 907 (manufactured by IGM Resins BV) 3 parts by weight - Diethyl-9-oxosulfur as a photoinitiator (KAYACURE DETX-S manufactured by Nippon Kayaku) 3 parts by weight

Next, the phase retardation film A prepared above was bonded to the pre-coated adhesive composition using a roller laminator. The bonding was performed at 30°C. Then, visible light (irradiation device: Light HAMMER10, Fusion UV Systems, Inc.; bulb: V-type bulb; peak illuminance: 1600 mW/ ^cm² ; cumulative irradiance 380~440 nm: 1000 mJ/ ^cm² ) was irradiated from the phase retardation film A as the active energy line to harden the adhesive composition. Finally, it was heat-dried at 70°C for 3 minutes to obtain the polarizing film A. The bending diameter of the polarizing film A obtained by the above method is 6.0 mm, and the bending moment M is 3.0 × ^10⁶ .

(Preparation of Polarizing Film B) Using a roller laminator, a protective film A with HC was laminated onto one main surface of the polarizing element A, and a transparent protective film (manufactured by Nippon Shokubai, 30µm thick) composed of a modified acrylic polymer with a lactone ring structure was laminated onto the other main surface. The lamination was performed using an adhesive at 30°C. The adhesive was an aqueous solution containing acetoacetyl PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetoacetylation 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1. The entire assembly was then dried in an oven to obtain polarizing film B. The bending diameter of polarizing film B obtained by the above method was 6.0 mm, and the bending moment M was 2.0 × ^10⁶ .

(Preparation of Polarizing Film C) Using a roller laminator, a transparent protective film containing triacetate cellulose (FUJIFILM TAC film, trade name "TG40UL", thickness 40µm) was laminated onto one main surface of the polarizing element A, and a transparent protective film composed of a modified acrylic polymer with a lactone ring structure (Nippon Shokubai, thickness 30µm) was laminated onto the other main surface. The lamination was performed using an adhesive at 30°C. The adhesive was an aqueous solution containing acetoacetyl PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetoacetylation 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1. The entire assembly was then dried in an oven to obtain polarizing film C. The bending diameter of the polarizing film C obtained by the above method is 3.0 mm, and the bending moment M is 3.5 × ^10⁶ .

(Preparation of Polarizing Film D) Using a roller laminator, a protective film A with HC was laminated onto one main surface of the polarizing element B, and a transparent protective film (manufactured by Nippon Shokubai, 30µm thick) composed of a modified acrylic polymer with a lactone ring structure was laminated onto the other main surface. The lamination was performed using an adhesive at 30°C. The adhesive was an aqueous solution containing acetoacetyl PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetoacetylation 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1. The entire assembly was then dried in an oven to obtain the polarizing film D. The polarizing film D, obtained by the above method, has a curl diameter of 7.8 mm and a bending moment M of 3.0 × ^10⁶ .

(Preparation of Polarizing Film E) Using a roller laminator, a transparent protective film containing triacetate cellulose (FUJIFILM TAC film, trade name "TG40UL", thickness 40µm) was laminated onto one main surface of the polarizing element C, and a transparent protective film composed of a modified acrylic polymer with a lactone ring structure (Nippon Shokubai, thickness 20µm) was laminated onto the other main surface. The lamination was performed using an adhesive at 30°C. The adhesive used was an aqueous solution containing acetoacetyl PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetoacetylation 5 mol%) and hydroxymethyl melamine in a weight ratio of 3:1. The entire assembly was then dried in an oven to obtain the polarizing film E. The bending diameter of the polarizing film E obtained by the above method is 2.5 mm, and the bending moment M is 8.0 × ^10⁶ .

<Fabrication of the First Laminate L1> Apply any of the prepared coating solutions to the exposed surfaces of the transparent protective films in each of the polarizing films prepared above, and allow the resulting coating film to dry at a predetermined temperature for 1 minute, thereby producing the first laminates L1-1 to L1-20 with an antistatic layer/polarizing film laminate structure. The manufacturing conditions and thickness of the antistatic layer of each of the first laminates L1 produced are listed in Table 2 below.

[Table 2]

[Evaluation of Antistatic Layer Characteristics] For each first laminate L1 produced, the product of the particle area ratio P (%) and the total current value Q (nA) before and after the DIN test was evaluated using the method described above: (P×0.01)×Q. The first laminate L1 was cut into rectangles of 5mm×30mm and fixed onto the AFM disc. When fixing the first laminate L1 to the mounting surface of the AFM disc, a double-sided conductive tape (manufactured by Nisshin EM Co., Ltd., trade name: Conductive Carbon Double-Sided Tape) was used. The conductive tape used consisted of a non-woven fabric substrate and an adhesive containing carbon powder as a conductive filler. Silver paste (Dortite D-550, manufactured by Fujikura Chemicals Co., Ltd.) was used for the metal paste application. The silver paste was applied in a solution of ethyl acetate and allowed to dry at room temperature for 30 minutes. After drying, the silver paste was used to verify the presence of a conductive path from the AFM disk to the antistatic layer in the measurement area. The AFM measuring device used was an AFM5300E manufactured by Hitachi High-Tech Co. The cantilever was a Hitachi High-Tech SI-DF40-R with rhodium coating on the back and front. The data from the AFM measurements were processed using the data analysis software included with the AFM measuring device. The evaluation was performed at 25°C. The evaluation results are shown in Table 3 below.

[Table 3]

[Preparation of the second laminate L2, consisting of a substrate and an adhesive sheet] <Preparation of (meth)acrylic polymer> In a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and cooler, a monomer mixture containing 67 parts by weight of 2-methoxyethyl acrylate (MEA), 22 parts by weight of n-butyl acrylate (BA), 10 parts by weight of phenoxyethyl acrylate (PEA), and 1 part by weight of 4-hydroxybutyl acrylate (HBA) was added. Next, relative to 100 parts by weight of the monomer mixture, 0.1 parts by weight of 2,2'-azobisisobutyronitrile (AIBN; manufactured by KISHIDA Chemical Co., Ltd.) as a polymerization initiator and 100 parts by weight of ethyl acetate were added together. While slowly stirring the mixture, nitrogen was introduced into the flask for nitrogen replacement. The liquid temperature in the flask was maintained at around 55°C for 8 hours to allow the polymerization reaction to proceed, thereby preparing a solution of (meth)acrylic acid polymer with a weight average molecular weight (Mw) of 2 million.

The weight-average molecular weight (Mw) of (meth)acrylic acid polymers was determined using GPC (gel osmosis chromatography). The determination conditions for GPC are shown below: • Analytical apparatus: Tosoh HLC-8120GPC • Column: Tosoh G7000HXL+GMHXL+GMHXL • Column dimensions: 7.8mm φ × 30cm (total 90cm) • Column temperature: 40℃ • Flow rate: 0.8mL/min • Injection volume: 100µL • Solution: Tetrahydrofuran • Detector: Differential refractometer (RI) • Standard sample: Polystyrene

<Preparation of Adhesive Sheet and Second Lamination L2> To the solid component of the above-prepared (meth)acrylic polymer solution, 0.3 parts by weight of a crosslinking agent (Tosoh Corporation, product name: Coronate 2770), 8 parts by weight of 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imidamine (EMI-FSI) (Daiichi Kogyo Pharmaceutical Co., Ltd., trade name: Elexcel AS110) as an antistatic agent, and 0.5 parts by weight of an antioxidant (BASF Corporation, trade name: Irganox 1010) were further mixed to prepare a solution of (meth)acrylic adhesive composition. Next, the prepared solution was applied to one side of a release film (Mitsubishi Polyester Film, MRF38). The release film used was a polyethylene terephthalate film surface-treated with a polysiloxane-based release agent. The coating film was dried at 155°C for 1 minute to obtain a second laminate L2-1 with an adhesive sheet on the surface of the release film. The thickness of the adhesive sheet was 20µm. Furthermore, except that the amount of antistatic agent added was set to 6 parts by weight, a second laminate L2-2 with an adhesive sheet on the surface of the release film was obtained in the same manner as described above. The surface resistivity of the adhesive sheets was evaluated for each of the fabricated second-stage laminates L2. The results for laminate L2-1 were 2.0 × ^10⁸ Ω/□, and for laminate L2-2 were 2.0 × ^10⁹ Ω/□. The surface resistivity of the adhesive sheets was measured in the same manner as that of the antistatic layer. The surface resistivity of the adhesive sheets remained almost unchanged before and after the DIN test.

[Fabrication of Optical Laminate] The adhesive sheet of the second laminate L2 fabricated above is bonded to the antistatic layer of the first laminate L1 to produce an optical laminate in which a polarizing film, an antistatic layer, an adhesive sheet, and a release film are sequentially laminated. Optical laminates fabricated using laminates L1-1 to L1-18 are examples 1 to 18. Optical laminates fabricated using laminates L1-19 and L1-20 are examples 1 and 2.

[Evaluation of Optical Laminates] ESD and TSP tests were performed on each manufactured optical laminate (before and after DIN testing). Furthermore, for each manufactured optical laminate (before DIN testing), the loss of total light transmittance and warping characteristics caused by the antistatic layer were evaluated.

(ESD Test) After peeling the release film from the optical laminate of the evaluation object, it is attached to the viewing side of the built-in image display panel (liquid crystal panel) with the configuration shown in Figure 8 using the adhesive sheet provided by the optical laminate. Next, a 10mm wide silver paste is applied to the side surface of the polarizing film and connected to an external ground electrode. The silver paste is applied by covering the polarizing film, the antistatic layer, and the side surface of the adhesive sheet. Then, the image display panel is placed on the backlight device, and an electrostatic discharge gun is fired at the polarizing film surface on the viewing side with a voltage of 9kV to check whether the display function is abnormal. The evaluation criteria are as follows: A: No abnormalities were observed on the screen, and the display function is normal. B: Horizontal lines or intermittent appearances occurred on the screen, but the display function automatically recovered. C: Horizontal lines or intermittent appearances occurred on the screen, and the display function could not be restored.

(TSP Test) After peeling the release film from the optical laminate of the evaluation object, it is bonded to the viewing side of the built-in image display panel (liquid crystal panel) with the configuration shown in Figure 8 through the adhesive sheet provided by the optical laminate. Next, the winding wiring around the transparent electrode pattern of the image display device with the bonded optical laminate is connected to the controller IC to create an image display device with built-in touch sensing function. The input display of the touch sensor to the device is visually observed to confirm whether there is a fault. A: No fault. D: Fault present.

(Loss of total light transmittance) The loss of total light transmittance is achieved by the method described above.

(Curling Characteristics) The degree of curling of each optical laminate was evaluated by visual observation. The evaluation criteria are as follows: A: Curling is well suppressed. B: Some curling, but no problem in use. C: Curling is observed, but no problem in use. D: Severe curling, which may cause problems in use.

The evaluation results are listed in Table 4 below.

[Table 4]

As shown in Table 4, in comparative examples 1 and 2 (E/D > 300) where the product of particle area ratio and total current value in the antistatic layer changes significantly due to the DIN test, the result of the ESD test before the DIN test is B, while the result of the TSP test after the DIN test is D. In the embodiments, in example 1 where the drying temperature during the formation of the antistatic layer is 70°C, in examples 6 and 7 where the solvent of the antistatic layer coating solution is 100% IPA or a mixture of IPA and water, and in examples 10 and 11 where a leveling agent is added to the antistatic layer coating solution, the E/D is greater than 10. Furthermore, in Embodiment 19, where the binder resin contains only resins with a Tg below 0°C, its E/D ratio is greater than 80. Moreover, in Embodiment 1, where the drying temperature during the formation of the antistatic layer is 70°C, and in Embodiments 6 and 7, where the solvent for the antistatic layer coating solution is 100% IPA or a mixture of IPA and water, the absolute value of the change in total light transmittance is 0.27% or more.

As shown in Table 4, if the drying temperature during the formation of the antistatic layer reaches 130°C or higher (Examples 4-5), and the smaller the diameter of the polarizing film used, the stronger the degree of curling.

Industrial Applicability: The optical multilayer of this invention is suitable for use in image display devices in environments such as vehicle interiors, where static electricity is easily generated due to the presence of other electronic devices, and where high temperature and humidity are easily reached.

1: Adhesive sheet; 2, 73A, 73B, 73C: Antistatic layer; 2B-2B, 2C-2C: Wire; 3: Optical thin film; 4: Peel-off liner; 10, 10A, 10B: Optical laminate; 11, 11A, 11B, 11C: Image display panel; 30A, 30B: Image display unit; 31: First transparent substrate; 32: Image forming layer; 33: Second transparent substrate; 35: Touch sensing electrode; 36: Touch sensor electrode. 7: Touch drive electrode 40: Conductive layer 51: Polarizing film 51C, 61C, 62C, 63C: Center surface 52: Test piece 53a: End 53b: Other end 54: Evaluation sheet 55: Cylindrical part 56: Adhesive tape 61: Polarizing element 62, 63: Transparent protective film 64A: One main surface 64B: Another main surface 71: Test sample 72: AFM disk 74: Conductive tape 75: Metal paste d ₆₁ , d ₆₂ , d ₆₃ : Distance P ₆₁ , P ₆₂ , P ₆₃ : Expansion force

Figure 1 is a cross-sectional view schematically showing an example of an optical laminate of this embodiment. Figure 2A is a top view schematically showing a test sample used for evaluating the particle area ratio and total current value in an antistatic layer. Figure 2B is a cross-sectional view schematically showing a test sample used for evaluating the particle area ratio and total current value in an antistatic layer. Figure 2C is a cross-sectional view schematically showing a test sample used for evaluating the particle area ratio and total current value in an antistatic layer. Figure 3 is a schematic diagram illustrating the test method for the bending diameter of a polarizing film. Figure 4 is a schematic diagram illustrating the bending moment M of a polarizing film during heating. Figure 5 is a cross-sectional view illustrating another example of the optical laminate of this embodiment. Figure 6 is a cross-sectional view illustrating an example of the image display panel of this embodiment. Figure 7 is a cross-sectional view illustrating another example of the image display panel of this embodiment. Figure 8 is a cross-sectional view illustrating another example of the image display panel of this embodiment.

1: Adhesive sheet

2: Antistatic layer

3: Optical Thin Films

10,10A: Optical laminates

Claims (22)

An optical laminate comprising an adhesive sheet, an antistatic layer, and an optical thin film; wherein the aforementioned antistatic layer contains conductive particles; and wherein the aforementioned antistatic layer satisfies the following formula (1); 0.01≦E/D≦300　　　　(1) However, D in the aforementioned formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the aforementioned antistatic layer as evaluated by atomic force microscopy (P×0.01)×Q; E in the aforementioned formula (1) is the product of the particle area ratio P (%) and the total current value Q (nA) of the antistatic layer as evaluated by atomic force microscopy after undergoing the weather resistance test specified by German industrial standard DIN75220 (test condition: Z-IN1) (P×0.01)×Q. For example, in the optical multilayer of claim 1, the thickness of the aforementioned antistatic layer is 5 nm or more and 100 nm or less. The optical laminate of claim 1, wherein the aforementioned conductive particles comprise carbon nanotubes. For example, in the optical laminate of claim 3, the aforementioned carbon nanotubes have a length of 3µm or more and 300µm or less, and a diameter of 10nm or less. The optical laminate of claim 1, wherein the aforementioned antistatic layer comprises an adhesive resin. The optical laminate of claim 1, wherein the aforementioned antistatic layer comprises an adhesive resin having a glass transition temperature of 0°C or higher. For example, in the optical laminate of claim 5, the glass transition temperature is above 0°C and the proportion of the aforementioned adhesive resin in all the aforementioned adhesive resin contained in the aforementioned antistatic layer is 50% by weight or more. The optical laminate of claim 1, wherein the aforementioned antistatic layer does not actually contain a leveling agent. As in claim 1, the optical laminate wherein the aforementioned adhesive sheet is formed from an adhesive composition containing polymer (A). For example, in the optical laminate of claim 9, the aforementioned polymer (A) is a (meth)acrylic polymer. As in claim 9, the optical laminate contains the aforementioned adhesive composition comprising the aforementioned polymer (A) having a polyether structure as the main component. The optical laminate of claim 11, wherein the aforementioned polymer (A) has structural units derived from the monomer shown in formula (2); [Chemical Formula 1] In formula (2), ^R1 is a hydrogen atom or a methyl group, ^R2 is an alkyl group that can be linear or branched, and n is an integer from 1 to 15. For example, in the optical laminate of claim 9, the aforementioned adhesive composition further includes an antistatic agent. For example, in the optical laminate of claim 13, the amount of the antistatic agent in the aforementioned adhesive composition is less than 30 parts by weight relative to 100 parts by weight of the aforementioned polymer (A). For example, in the optical laminate of claim 1, the loss of total light transmittance due to the aforementioned antistatic layer is less than 1.0%. The optical laminate of claim 1, wherein the aforementioned optical thin film includes a polarizing thin film. For example, in the optical laminate of claim 16, the bending diameter of the aforementioned polarizing film is 3 mm or more as evaluated by the following test method: <Test Method> Prepare a test piece, which is a rectangle with the absorption axis of the polarizing element as the long side direction, and the aforementioned optical film is processed into a rectangle with a width of 10 mm and a length of 50 mm; then, fix one end of the long side direction of the aforementioned test piece to the surface of the evaluation sheet; then, heat the whole body at 105°C for 12 hours, so that the aforementioned test piece is bent from the other end of the long side direction of the aforementioned test piece; determine the diameter of the cylindrical portion formed by the bending of the aforementioned test piece as the aforementioned bending diameter. For example, in the optical laminate of claim 16, the absolute value of the bending moment M of the aforementioned polarizing film when heated is less than 1× ^10⁹ . The optical laminate of claim 1, wherein the aforementioned conductive particles comprise carbon nanotubes; and the aforementioned antistatic layer comprises a binder resin with a glass transition temperature of 0°C or higher. For example, in the optical laminate of claim 19, the aforementioned carbon nanotubes have a length of 3µm or more and 300µm or less, and a diameter of 10nm or less. An image display panel having an optical layer as described in any of claims 1 to 20. An image display device having an image display panel as claimed in claim 21.