Optical laminate, image display panel, and image display device

Abstract

The optical laminate provided by this invention comprises an adhesive sheet, an antistatic layer, and an optical film. The antistatic layer satisfies the following formula (1). Wherein, A and B in formula (1) are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test conditions: Z-IN1) specified by German industrial standard DIN75220. The above optical laminate is suitable for use in image display devices used in harsh environments such as automotive applications. -2≤logB-logA≤2 (1).

Description

Technical Field

[0001] This invention relates to optical laminates, image display panels, and image display devices. Background Technology

[0002] Image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), have become widespread. These image display devices, for example, have a laminated structure comprising image display units such as liquid crystal cells and EL light-emitting elements, and an optical laminate including a polarizing film and an adhesive sheet. The adhesive sheet is mainly used for bonding between films contained in the optical laminate and for bonding the image display element to the optical laminate.

[0003] Image display devices sometimes generate static electricity during manufacturing or use. During manufacturing, static electricity is easily generated when the optical laminate is bonded to the image display unit via 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 defects may occur. Patent Document 1 discloses an optical laminate comprising a polarizing film and a conductive layer containing a conductive polymer.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2015-509615 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Based on the research of the inventors, the optical laminate of Patent Document 1 still has room for further improvement depending on the environment in which the image display device is used. The object of the present invention is to provide an optical laminate suitable for use in harsh environments such as automotive applications.

[0009] Problem Solving Methods

[0010] This invention provides an optical laminate comprising: an adhesive sheet, an antistatic layer, and an optical film.

[0011] The above-mentioned antistatic layer satisfies the following equation (1).

[0012] -2≤logB-logA≤2 (1)

[0013] In formula (1), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test conditions: Z-IN1) specified by German industrial standard DIN75220.

[0014] Furthermore, the present invention provides an optical laminate comprising, in sequence, an adhesive sheet, an antistatic layer, and an optical film.

[0015] The optical laminate satisfies the following equation (4).

[0016] -1≤logD-logC≤2 (4)

[0017] Wherein, C in the above formula (4) is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that is opposite to the antistatic layer.

[0018] In the above formula (4), D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that is opposite to the above antistatic layer, after passing the weather resistance test specified by German industrial standard DIN75220 (test conditions: Z-IN1).

[0019] Furthermore, the present invention provides an image display panel having the aforementioned optical laminate.

[0020] Furthermore, the present invention provides an image display device having the aforementioned image display panel.

[0021] The effects of the invention

[0022] According to the present invention, an optical laminate suitable for use in harsh environments such as automotive applications can be provided. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view schematically showing an example of an optical laminate of this embodiment.

[0024] Figure 2 This is a schematic diagram illustrating a test method for determining the curl diameter of a polarizing film.

[0025] Figure 3 This is a schematic diagram illustrating the bending moment M during the heating of the polarizing film.

[0026] Figure 4 This is a cross-sectional view schematically showing another example of the optical laminate of this embodiment.

[0027] Figure 5 This is a cross-sectional view schematically showing an example of an image display panel of this embodiment.

[0028] Figure 6 This is a cross-sectional view schematically illustrating another example of the image display panel of this embodiment.

[0029] Figure 7This is a cross-sectional view schematically illustrating another example of the image display panel of this embodiment. Detailed Implementation

[0030] The optical laminate of the first embodiment of the present invention comprises: an adhesive sheet, an antistatic layer, and an optical film.

[0031] The above-mentioned antistatic layer satisfies the following equation (1).

[0032] -2≤logB-logA≤2 (1)

[0033] In formula (1), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test conditions: Z-IN1) specified by German industrial standard DIN75220.

[0034] In a second aspect of the present invention, for example, in the optical laminate of the first aspect, the surface resistivity B of the antistatic layer is 1.0 × 10⁻⁶. 6 Ω / □ or higher and 3.0 × 10 8 Below Ω / □.

[0035] In a third aspect of the present invention, for example, in the optical laminate of the first or second aspect, the thickness of the antistatic layer is 5 nm or more and 100 nm or less.

[0036] In a fourth aspect of the present invention, for example, in an optical laminate of any one of the first to third aspects, the antistatic layer comprises carbon nanotubes.

[0037] In a fifth aspect of the present invention, for example, in the optical laminate of the fourth aspect, the length of the carbon nanotubes is 3 μm or more and 300 μm or less, and the diameter is 10 nm or less.

[0038] In a sixth aspect of the present invention, for example, in an optical laminate of any one of the first to fifth aspects, the antistatic layer comprises an adhesive resin.

[0039] In the seventh aspect of the present invention, for example, in the optical laminate of any one of the first to sixth aspects, the antistatic layer comprises an adhesive resin with a glass transition temperature of 0°C or higher.

[0040] In the eighth aspect of the present invention, for example, in the optical laminate of any one of the first to seventh aspects, the antistatic layer does not substantially contain a leveling agent.

[0041] In the ninth aspect of the present invention, for example, in the optical laminate of any one of the first to eighth aspects, the adhesive sheet is formed from an adhesive composition comprising polymer (A).

[0042] In the tenth aspect of the present invention, for example, in the optical laminate of the ninth aspect, the polymer (A) is a (meth)acrylic polymer.

[0043] In the eleventh aspect of the present invention, for example, in the optical laminate of the ninth or tenth aspect, the adhesive composition comprises the polymer (A) having a polyether structure as the main component.

[0044] In the 12th aspect of the present invention, for example, in the optical laminate of the 11th aspect, the polymer (A) has structural units derived from the monomers shown in the following formula (2).

[0045] [Chemical Formula 1]

[0046]

[0047] R in equation (2) 1 R is a hydrogen atom or a methyl group. 2 The alkyl group is an alkyl group, which may be a straight-chain alkyl group or a branched alkyl group, and n is an integer from 1 to 15.

[0048] In a 13th embodiment of the invention, for example, in an optical laminate of any one of embodiments 9 to 12, the adhesive composition further comprises an antistatic agent.

[0049] In the 14th aspect of the present invention, for example, in the optical laminate of the 13th aspect, the amount of the antistatic agent in the adhesive composition is less than 30 parts by weight relative to 100 parts by weight of the polymer (A).

[0050] In the 15th aspect of the present invention, for example, in the optical laminate of any one of the 1st to 14th aspects, the loss of total light transmittance caused by the antistatic layer is 1.0% or less.

[0051] In the 16th aspect of the present invention, for example, in the optical laminate of any one of the 1st to 15th aspects, the optical film includes a polarizing film.

[0052] In the 17th aspect of the present invention, for example, in the optical laminate of the 16th aspect, the curl diameter of the polarizing film evaluated by the following test method is 3 mm or more.

[0053] <Experimental Method>

[0054] A rectangular test piece, 10 mm wide and 50 mm long, was prepared by processing the polarizing film along the absorption axis of the polarizer. Next, one end of the test piece along its length was fixed to the surface of an evaluation sheet. Then, the entire piece was heated at 105°C for 12 hours, causing the test piece to curl from the other end along its length. The diameter of the cylindrical portion of the curled test piece was determined as the curling diameter.

[0055] In the 18th aspect of the present invention, for example, in the optical laminate of the 16th or 17th aspect, the absolute value of the bending moment M of the polarizing film during heating is less than 1 × 10⁻⁶. 9 .

[0056] In the 19th aspect of the present invention, for example, in the optical laminate of any one of the 1st to 18th aspects, the antistatic layer comprises carbon nanotubes and an adhesive resin with a glass transition temperature of 0°C or higher.

[0057] In the 20th aspect of the present invention, for example, in the optical laminate of the 19th aspect, the length of the carbon nanotube is 3 μm or more and 300 μm or less, and the diameter is 10 nm or less.

[0058] In the 21st embodiment of the present invention, for example, the optical laminate of any one of the 1st to 20th embodiments sequentially includes the above-mentioned adhesive sheet, the above-mentioned antistatic layer, and the above-mentioned optical film, and satisfies the following formula (4).

[0059] -1≤logD-logC≤2 (4)

[0060] Wherein, C in the above formula (4) is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that is opposite to the antistatic layer.

[0061] In the above formula (4), D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that has undergone the above weathering test, which is opposite to the antistatic layer.

[0062] The optical laminate of the 22nd embodiment of the present invention comprises, in sequence, an adhesive sheet, an antistatic layer, and an optical film, and satisfies the following formula (4).

[0063] -1≤logD-logC≤2 (4)

[0064] Wherein, C in the above formula (4) is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that is opposite to the antistatic layer.

[0065] In the above formula (4), D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the above optical laminate that is opposite to the above antistatic layer, after passing the weather resistance test specified by German industrial standard DIN75220 (test conditions: Z-IN1).

[0066] The image display panel of the 23rd embodiment of the present invention comprises an optical laminate of any one of the 1st to 22nd embodiments.

[0067] The image display device of the 24th embodiment of the present invention includes the image display panel of the 23rd embodiment.

[0068] The present invention will now be described in detail. However, the present invention is not limited to the embodiments shown below. The present invention can be implemented in any way without departing from its spirit.

[0069] [Optical laminate]

[0070] An example of the optical laminate of this embodiment is shown below. Figure 1 . Figure 1 The optical laminate 10 (10A) includes an adhesive sheet 1, an antistatic layer 2, and an optical film 3. The optical laminate 10A has a structure in which the adhesive sheet 1, the antistatic layer 2, and the optical film 3 are sequentially stacked. The stacking order of the layers in the optical laminate is not limited to... Figure 1 For example, the optical laminate 10A can be bonded to an object such as an image display panel via the adhesive sheet 1.

[0071] Figure 1 The adhesive sheet 1 is bonded to the antistatic layer 2. Other films and / or layers may be disposed between the adhesive sheet 1 and the antistatic layer 2. Furthermore, viewed from the lamination direction, Figure 1 The adhesive sheet 1 is formed integrally on one main surface of the antistatic layer 2. However, viewed from 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 of the film or layer with the largest area.

[0072] Figure 1 The optical film 3 is in contact with the antistatic layer 2. Other films and / or layers may be disposed between the optical film 3 and the antistatic layer 2. Furthermore, viewed from the stacking direction, Figure 1 The optical film 3 is formed integrally on another main surface of the antistatic layer 2. However, when viewed from the stacking direction, the optical film 3 may be formed on a portion of the other main surface of the antistatic layer 2.

[0073] Figure 1 The antistatic layer 2 is sandwiched between the adhesive sheet 1 and the optical film 3.

[0074] <Antistatic layer>

[0075] The antistatic layer 2 satisfies the following formula (1). In formula (1), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer 2 before and after the weathering test (test conditions: Z-IN1) specified by German industrial standard DIN75220.

[0076] -2≤logB-logA≤2 (1)

[0077] According to the research of the inventors, the resistance change of the antistatic layer 2 due to exposure to harsh environments such as automotive applications may be a cause of display defects. Furthermore, in image display devices incorporating touch sensors, the resistance change of the antistatic layer 2 may cause touch sensor malfunctions. The weathering test specified in DIN 75220 (hereinafter referred to as the "DIN test") is a weathering test that takes into account the aforementioned harsh environments. In the antistatic layer 2, the change in surface resistivity before and after the DIN test is suppressed. Therefore, the optical laminate 10 with the antistatic layer 2 is more suitable for suppressing display defects. It should be noted that the test condition Z-IN1 in the DIN test is an indoor (Zone 1) test, which refers to a cyclic test (Z) consisting of a 15-day dry climate cycle followed by a 10-day humid climate cycle. In the dry climate cycle, one cycle consists of (1) 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. This cycle is repeated for 15 days. Between (4) of one cycle and (1) of the next cycle, the sample is placed at room temperature (23°C) for 1 hour. In the humid climate cycle, one cycle consists of (1) placement in an atmosphere with a temperature of -10°C (without ultraviolet light) for 5 hours, (2) irradiation with ultraviolet light for 12 hours in an atmosphere with a temperature of 80°C and a relative humidity of 50%, and (3) placement in an atmosphere with a temperature of -10°C (without ultraviolet light) for 6 hours. This cycle is repeated for 10 days. Between (3) of one cycle and (1) of the next cycle, the components are placed at room temperature for 1 hour. Indoor (Zone 1) is a classification of the installation location of vehicle components and materials inside the vehicle, referring to interior components and materials that are exposed to high temperatures but are exposed to less intense sunlight than exterior components. The illuminance of the metal halide lamp used for ultraviolet irradiation is set to 830 W / m. 2 .

[0078] In equation (1), logB-logA can be greater than or equal to 1.7 and less than 1.7, greater than or equal to 1.5 and less than 1.5, greater than or equal to 1.3 and less than 1.3, greater than or equal to 1.2 and less than 1.2, greater than or equal to 1.1 and less than 1.1, greater than or equal to 1 and less than 1, greater than or equal to 0.9 and less than 0.9, greater than or equal to 0.8 and less than 0.8, greater than or equal to 0.7 and less than 0.7, greater than or equal to 0.6 and less than 0.6, and further can be greater than or equal to 0.5 and less than 0.5.

[0079] The value of logB-logA in equation (1) varies depending on the composition and formation method of the antistatic layer 2. Examples of composition include the type and content of conductive materials, as well as the type, content, and properties of materials other than conductive materials. Examples of materials other than conductive materials include adhesive resins and leveling agents. 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.

[0080] The surface resistivity B (surface resistivity after DIN test) of antistatic layer 2 is, for example, 1.0 × 10⁻⁶. 9 Ω / □ or less. It has 3.0 × 10 8 An antistatic layer 2 with a surface resistivity B of less than Ω / □ is particularly suitable for suppressing display defects in image display devices. The surface resistivity B can be 5.0 × 10⁻⁶. 8 Ω / □ or less, 2.0×10 8 Ω / □ or less, 1.0×10 8 Ω / □ or less, 9.0×10 7 Ω / □ or less, 8.0×10 7 Ω / □ or less, 7.0×10 7 Ω / □ or less, 6.0×10 7 Ω / □ or less, 5.0×10 7 Ω / □ or less, 4.0×10 7 Ω / □ or less, and further up to 3.0×10 7 Below Ω / □. The lower limit of surface resistivity B is, for example, 1.0 × 10⁻⁶. 6 Ω / □ or higher, can be 2.0×10 6 Ω / □ or more, 3.0×10 6 Ω / □ or higher, 4.0×10 6 Ω / □ or above, 5.0×10 6 Ω / □ or higher, 6.0×10 6 Ω / □ or above, 7.0×10 6 Ω / □ or above, 8.0×10 6 Ω / □ or above, 9.0×10 6Ω / □ or higher, and further up to 1.0 × 10 7 Ω / □ or higher. It has 2.0 × 10 6 Ω / □ or above, 5.0×10 6 Ω / □ or higher, further 1.0 × 10 7 An antistatic layer 2 with a surface resistivity B of Ω / □ or higher helps ensure the touch sensitivity of image display devices equipped with touch sensors or touch panels, especially in-cell image display devices described later. The surface resistivity B of the antistatic layer 2 can be 1.0 × 10⁻⁶. 6 Ω / □ or higher and 3.0 × 10 8 Ω / □ or less, 1.0×10 6 Ω / □ or higher and 1.0 × 10 8 Ω / □ or less, 1.0×10 6 Ω / □ or higher and 1.0 × 10 7 Ω / □ or less, and further up to 5.0 × 10 6 Ω / □ or higher and 1.0 × 10 7 Below Ω / □.

[0081] The example range for the selectable range of surface resistivity A (surface resistivity before DIN test) of antistatic layer 2 is the same as the example range for the selectable range of surface resistivity B. The surface resistivity A of antistatic layer 2 can be 1.0 × 10⁻⁶. 6 Ω / □ or higher and 3.0 × 10 8 For values ​​below Ω / □, 1.0 × 10 can also be used. 7 Ω / □ or higher and 1.0 × 10 8 Below Ω / □, it can be further reduced to 1.0 × 10 7 Ω / □ or higher and 5.0 × 10 7 Below Ω / □.

[0082] The antistatic layer 2 can be a layer whose surface resistivity is maintained or reduced through DIN testing. In other words, the relationship between surface resistivity A and surface resistivity B can be expressed by the equation: surface resistivity B ≤ surface resistivity A, or by the equation: surface resistivity B < surface resistivity A.

[0083] The surface resistivity A and B of the antistatic layer 2 can be determined by the following method. A laminate with the surface of the antistatic layer 2 exposed to the outside is prepared. An example of this laminate is a laminate containing an optical film 3 and the antistatic layer 2. Next, the surface resistivity of the exposed surface of the antistatic layer 2 in the prepared laminate is measured. The surface resistivity can be measured using a high-resistivity resistivity meter (for example, a Hiresta series manufactured by Mitsubishi Chemical Analytech Co., Ltd.) according to the method specified in Japanese Industrial Standard (JIS) K6911:1995. The surface resistivity A and B are measured under the conditions of an applied voltage of 10V, an application time of 10 seconds, and an ambient temperature of 25±3℃.

[0084] The antistatic layer 2 typically contains a conductive material. Examples of conductive materials include conductive polymers, composites of conductive polymers and dopants, conductive microparticles, carbon materials, ionic surfactants, and ionic compounds. Examples of carbon materials include acetylene black, Ketjen black, natural graphite, artificial graphite, and carbon nanotubes (CNTs). According to the researchers of the present invention, carbon materials are suitable as conductive materials contained in the antistatic layer 2, and CNTs are particularly suitable. In other words, the antistatic layer 2 can contain either carbon materials or CNTs. The reason for the suitability of carbon materials is that, compared to conductive polymers, composites of conductive polymers and dopants, they are less prone to degradation under the aforementioned harsh environments, typically less prone to oxidation. If the conductive material deteriorates, the surface resistivity of the antistatic layer 2 typically tends to increase. Furthermore, CNTs are particularly suitable among carbon materials because they help suppress aggregation and orientation under high temperature and high humidity conditions due to the high shape anisotropy of CNTs. The antistatic layer 2 can contain two or more conductive materials, or it can contain CNTs and other conductive materials (e.g., conductive polymers).

[0085] There are no limitations on the types of CNTs; they can be manufactured using various methods such as arc discharge, laser evaporation, and chemical vapor deposition (CVD). CNTs can be monolayer, bilayer, or multilayer CNTs, or mixtures of two or more of them. From the viewpoint of excellent conductivity, monolayer CNTs are particularly suitable.

[0086] The length of CNTs is, for example, 1~2000μm, or 1~1000μm, or even 1~500μm. The diameter (outer diameter) of CNTs is, for example, 0.1~50nm, or 0.2~40nm, 0.25~30nm, 0.3~20nm, 0.4~15nm, or even 0.5~10nm. The diameter of CNTs can be less than 9nm, less than 8nm, less than 7nm, less than 6nm, less than 5nm, less than 4.5nm, less than 4nm, less than 3.5nm, less than 3nm, less than 2.5nm, or even less than 2nm. From the viewpoint of dispersion in the antistatic layer 2, the length of the CNT can be less than 300 μm, and can be less than 300 μm, less than 275 μm, less than 250 μm, less than 225 μm, less than 200 μm, less than 175 μm, less than 150 μm, less than 125 μm, less than 100 μm, less than 90 μm, less than 80 μm, less than 70 μm, less than 60 μm, less than 50 μm, less than 40 μm, less than 30 μm, less than 25 μm, less than 20 μm, less than 15 μm, less than 10 μm, less than 10 μm, less than 9 μm, less than 8 μm, less than 7 μm, less than 6 μm, and further can be less than 5 μm. Furthermore, from the viewpoint of dispersion in the antistatic layer 2, the length of the CNT can be more than 3 μm and less than 300 μm, and the diameter can be less than 10 nm. The length of CNTs can be evaluated by observation using interatomic force microscopy (AFM) or scanning electron microscopy (SEM). The diameter of CNTs can be determined according to ISO / TS10868:2017.

[0087] The CNT content in the antistatic layer 2 is, for example, 0.01~50.0 mg / m³. 2 The dosage can range from 0.1 to 10.0 mg / m³. 2 The proportion of CNTs in the total solid components contained in the antistatic layer 2 is, for example, 0.01 to 90 wt%, and can be 0.01 to 50 wt%, 0.01 to 30 wt%, 0.05 to 25 wt%, 0.1 to 20 wt%, 0.15 to 15 wt%, 0.2 to 10 wt%, 0.25 to 7.5 wt%, 0.5 to 5 wt%, and more preferably 0.75 to 3 wt%. From the viewpoint of suppressing the loss of total light transmittance as an optical laminate 10, the above proportion is preferred to be small.

[0088] Known materials can be used in conductive polymers, composites of conductive polymers and dopants, conductive microparticles, ionic surfactants, and ionic compounds.

[0089] The antistatic layer 2 may contain one or more conductive materials.

[0090] The antistatic layer 2 may contain materials other than conductive materials. Examples of other materials include adhesive resin. In other words, the antistatic layer 2 may contain adhesive resin. The presence of adhesive resin can help improve the film-forming properties of the antistatic layer 2, as well as the adhesion and bonding (anchoring force) of the antistatic layer 2 to the optical film 3.

[0091] Examples of adhesive resins include those containing The adhesive resin includes azoline polymers, polyurethane resins, polyester resins, acrylic resins, polyether resins, cellulose resins, polyvinyl alcohol resins, epoxy resins, polyvinylpyrrolidone, polystyrene resins, polyethylene glycol, and pentaerythritol. The preferred adhesive resin contains... The adhesives used are zoline polymers, polyurethane resins, polyester resins, and acrylic resins, with polyurethane resins and / or acrylic resins being particularly preferred. The antistatic layer 2 may contain one or more adhesive resins, or only one. A combination of two or more adhesive resins may be a combination of polyurethane resin and acrylic resin. The adhesive content in the antistatic layer 2 is, for example, 1 to 99.99% by weight, and may be 50 to 99.99% by weight, 60 to 99.99% by weight, 70 to 99.99% by weight, 80 to 99.99% by weight, and further may be 90 to 99.99% by weight.

[0092] The glass transition temperature (Tg) of the adhesive resin can be above 0°C, or above 20°C, 30°C, 40°C, 50°C, 55°C, or even above 60°C. The upper limit of Tg is, for example, below 100°C. In other words, the antistatic layer 2 can contain an adhesive resin with a Tg of 0°C or higher. According to the researchers of the present invention, when using an adhesive resin, a Tg of the adhesive resin within the above-mentioned range can help suppress changes in the surface resistivity of the antistatic layer 2 before and after the DIN test. It can be presumed that the higher the Tg of the adhesive resin, the better it suppresses the movement of conductive materials contained in the antistatic layer 2 due to heat and the resulting aggregation and orientation. Aggregation and orientation can increase the non-uniformity of conductive materials within the antistatic layer 2, causing changes in surface resistivity. According to the researchers of the present invention, if the non-uniformity of CNTs increases, the surface resistivity tends to decrease. Suppression of changes in surface resistivity based on the Tg of the adhesive resin may be based on suppression of the movement of conductive materials during the heating cycle of the DIN test. Unless otherwise specified, the Tg of polymers in this specification refers to the Tg calculated using the Fox formula based on the composition of the monomer components. Unless otherwise specified, the Tg of resins (including adhesive resins) in this specification refers to the Tg determined by differential scanning calorimetry (DSC). The DSC measurement conditions are described below.

[0093] • Gas atmosphere: Nitrogen (50 mL / min)

[0094] • Measurement temperature range: 0℃→100℃

[0095] • Heating rate: 10℃ / minute

[0096] • Sample amount: Approximately 3 mg (for sample containers, an aluminum Tzero pan can be used).

[0097] When the antistatic layer 2 contains an adhesive with a Tg of 0°C or higher, the proportion of the adhesive resin with a Tg of 0°C or higher to the total adhesive resin contained therein can be 50% by weight or higher, and can be 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 further can be 94% by weight or higher. The upper limit of this proportion is, for example, 100% by weight or lower, and can be 99% by weight or lower, 98% by weight or lower, 97% by weight or lower, 96% by weight or lower, and further can be 95% by weight or lower.

[0098] For the antistatic layer 2, especially when it contains two or more adhesive resins, it may contain adhesive resins with a Tg below 0°C. For example, the antistatic layer 2 may contain adhesive resins with a Tg of 0°C or higher and adhesive resins with a Tg below 0°C. The lower limit of the Tg of the adhesive resin having a Tg below 0°C is, for example, -70°C or higher, and may be -60°C or higher, -50°C or higher, -45°C or higher, or even -40°C or higher. Depending on the composition of the antistatic layer 2, adhesive resins with a Tg below 0°C may sometimes help improve its film-forming properties and the dispersibility of CNTs in the antistatic layer 2 during film formation. When the antistatic layer 2 contains adhesive resin with a Tg of 0°C or higher and adhesive resin with a Tg of lower than 0°C, the proportion of adhesive resin with a Tg of lower than 0°C to the total adhesive resin contained therein can 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, and further can be 5% by weight or less. The lower limit of this proportion is, for example, 1% by weight or more, or 2% by weight or more, 3% by weight or more, 4% by weight or more, and further can be 5% by weight or more.

[0099] The antistatic layer 2 may contain a leveling agent. Preferably, the leveling agent content in the antistatic layer 2 is low. According to the research of the inventors, not adding a leveling agent to the coating liquid used to form the antistatic layer 2 can help reduce the absolute value of logB-logA in formula (1). The leveling agent may promote the movement of the conductive material contained in the antistatic layer 2 due to heat. The leveling agent content is less than 5% by weight, and can be 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.5% by weight or less, and further can be 0.1% by weight or less. The antistatic layer 2 may substantially not contain a leveling agent. In this specification, substantially not containing means a content of less than 0.01% by weight.

[0100] The inhomogeneity of the conductive material contained in the antistatic layer 2 affects the light transmittance of the optical laminate 10. According to the research of the inventors, if the inhomogeneity of the CNTs (conductive nanomaterials) as conductive material is increased, the light transmittance of the optical laminate 10 tends to decrease. From this perspective, the total loss of light transmittance of the optical laminate 10 caused by the antistatic layer 2 can be 1.0% or less. The total light transmittance loss can be 0.90% or less, 0.80% or less, 0.70% or less, 0.60% or less, 0.50% or less, 0.45% or less, 0.40% or less, 0.35% or less, 0.30% or less, 0.25% or less, 0.20% or less, 0.15% or less, and more preferably 0.10% or less. A low total light transmittance loss is preferred. Regarding the loss of total light transmittance, the total light transmittance T2 of the optical laminate 10 being evaluated can be measured, and the total light transmittance T1 of an optical laminate having the same structure except for the absence of the antistatic layer 2 can be measured, and the difference between the two (T1-T2) can be used. In this specification, total light transmittance refers to the transmittance of light in the wavelength range of 380 to 700 nm. Total light transmittance can be measured according to the provisions of Japanese Industrial Standard (hereinafter referred to as JIS) K7361-1:1997. A D65 light source is used in the measurement of total light transmittance. Furthermore, the light during measurement is incident from the optical film 3 side.

[0101] The thickness of the antistatic layer 2 is, for example, 5 to 1500 nm, and can be less than 1400 nm, less than 1300 nm, less than 1200 nm, less than 1100 nm, less than 1000 nm, less than 900 nm, less than 800 nm, less than 700 nm, less than 600 nm, less than 500 nm, less than 400 nm, less than 300 nm, less than 200 nm, less than 180 nm, less than 150 nm, less than 120 nm, less than 100 nm, less than 90 nm, less than 80 nm, less than 70 nm, less than 60 nm, less than 55 nm, less than 50 nm, less than 45 nm, and further less than 40 nm. The thickness can be more than 10 nm, more than 20 nm, more than 25 nm, more than 30 nm, more than 40 nm, and further more than 45 nm. It should be noted that, according to the research of the inventors, for antistatic layers 2 with the same composition and formation method, there is a tendency for the loss of the aforementioned total light transmittance to be smaller as the thickness of the layer 2 becomes smaller.

[0102] The antistatic layer 2 may contain CNTs and an adhesive resin with a Tg of 0°C or higher. In this case, the length of the CNTs is 3μm or more and 300μm or less, and the diameter can be 10nm or less.

[0103] <Adhesive Sheet>

[0104] Typically, adhesive sheet 1 is a layer formed from an adhesive composition (I) containing a polymer (A).

[0105] (Polymer(A))

[0106] Examples of polymer (A) include (meth)acrylic polymers, urethane polymers, silicone polymers, and rubber polymers. Polymer (A) is preferably a (meth)acrylic polymer. The adhesive composition (I) may contain a (meth)acrylic polymer as a main component; in other words, the adhesive composition (I) may be an acrylic adhesive composition. In this specification, the main component refers to the component with the highest content in the composition by weight. The content of the main component is, for example, 50% by weight or more, and may be 60% by weight or more, 70% by weight or more, 75% by weight or more, and further, 80% by weight or more. In this specification, a (meth)acrylic polymer refers to a polymer having structural units derived from (meth)acrylic monomers such as (meth)acrylates. The content of such structural units in the (meth)acrylic polymer is, for example, 40% by weight or more, and may be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, and further, 95% by weight or more. (Meth)acrylic polymers can also be composed solely of structural units derived from (meth)acrylic monomers. (Meth)acrylic acid refers to acrylic acid and methacrylic acid. (Meth)acrylates refer to acrylates and methacrylates.

[0107] Polymer (A) may have a polyether structure. The adhesive composition (I) may contain 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 optionally 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 be a (meth)acrylic polymer having a polyether structure in its side chains.

[0108] Polymer (A) may have structural units having a polyether structure. In this structural unit, the polyether structure may be located in the main chain or in the side chain, preferably in the side chain. Polymer (A) may have structural units derived from (meth)acrylic monomers having a polyether structure in the side chain.

[0109] The polymer (A) having a polyether structure in its side chain has, for example, structural units derived from monomer A1 as shown in formula (2) below. In other words, polymer (A) can have structural units derived from monomers shown in formula (2) below. R in formula (2) 1 It can be a hydrogen atom or a methyl group. R 2 It is optionally a straight-chain or branched alkyl group, preferably a straight-chain alkyl group. The alkyl group has 1 to 10 carbon atoms, and more preferably 1 to 4. R 2Examples include methyl and ethyl. n is an integer from 1 to 15, preferably from 1 to 10, and more preferably from 1 to 5. When n is 1, monomer A1 contains two ether groups, including the "-O-" of the COO group. Monomer A1 is a type of (meth)acrylic acid monomer, and more specifically, a type of (meth)acrylate monomer. From the R at the end of the side chain... 2 From the perspective of the O group, monomer A1 is also a type of alkoxy-containing (meth)acrylate monomer. The structural units derived from monomer A1 have a polyether structure in the side chain.

[0110] [Chemical Formula 2]

[0111]

[0112] Examples of monomer A1 are 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). The structural units derived from monomer A1 can help reduce the surface resistivity of the adhesive sheet 1 formed from the adhesive composition (I).

[0113] The content of the polyether-structured structural units in polymer (A) is, for example, 0% by weight or more, and can 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 more preferably 50% by weight or more. The upper limit of this content is, for example, 100% by weight or less, and can 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 more preferably less than 60% by weight. Furthermore, the content of the structural units derived from monomer A1 in polymer (A) can be within the above range.

[0114] Polymer (A) may also not have structural units with polyether structures.

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

[0116] Examples of monomer A2 are (meth)acrylic acid monomers having alkyl groups with 1 to 30 carbon atoms in the side chain. The alkyl group can be linear or branched. Examples of (meth)acrylate monomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, isohexyl methacrylate, isoheptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, n-decyl methacrylate, isodecyl methacrylate, n-dodecyl methacrylate (laurate methacrylate), n-tridecyl methacrylate, n-tetradecyl methacrylate, n-pentadecanyl methacrylate, n-hexadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, and octadecyl methacrylate. The content of the structural unit derived from the above-mentioned (meth)acrylic acid monomer in polymer (A) is, for example, 80% by weight or less, and may be 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, and may be 5% by weight or less, or may be 0% by weight (not having the structural unit).

[0117] Another example of monomer A2 is a hydroxyl-containing monomer. The hydroxyl-containing monomer can be a hydroxyl-containing (meth)acrylate monomer. Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylaurate (meth)acrylate, as well as methyl (4-hydroxymethylcyclohexyl)acrylate. From the viewpoint of improving the durability of the adhesive sheet 1 formed from the adhesive composition (I), 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred. The content of structural units derived from hydroxyl-containing monomers in the polymer (A) is, for example, 1 to 5% by weight, but can be 3% by weight or less, and more further, 2% by weight or less. The polymer (A) may also not have structural units derived from hydroxyl-containing monomers.

[0118] Monomer A2 can be an aromatic ring monomer, a carboxyl monomer, an amino monomer, or an amide monomer.

[0119] The aromatic ring monomer can be an aromatic ring-containing (meth)acrylate monomer. Examples of aromatic ring-containing monomers are phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, hydroxyethylated β-naphthol (meth)acrylate, and biphenyl (meth)acrylate. During the manufacture and / or use of an image display device comprising the optical laminate 10, birefringence may sometimes occur due to the misalignment of the adhesive sheet. If birefringence occurs, the image display device may experience problems such as light leakage and uneven display. The inclusion of structural units derived from aromatic ring monomers can help reduce birefringence that may occur due to the misalignment of the aforementioned adhesive sheet.

[0120] The aromatic ring-containing monomer can be monomer A3 as shown in formula (3). R in formula (3) 3 R is a hydrogen atom or a methyl group. In formula (3), R... 4 The hydrogen atom is optionally replaced by a phenyl group, preferably a phenyl group. The substituent for the hydrogen atom is, for example, a linear or branched alkyl group having 1 to 10 carbon atoms, further having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 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 A3 is a (meth)acrylate monomer, more specifically, a (meth)acrylate ester monomer. Monomer A3 contains two ether groups, including a "-O-" group of COO. In other words, the structural unit derived from monomer A3 is also a structural unit having a polyether structure. It should be noted that the content of the structural unit derived from monomer A3 in polymer (A) is included in the content of the structural unit having a polyether structure.

[0121] [Chemical Formula 3]

[0122]

[0123] An example of monomer A3 is phenoxyethyl (meth)acrylate.

[0124] Polymer (A) having structural units derived from monomer A3 can help improve the durability of optical laminate 10. In addition, even when optical laminate 10 includes an optical film 3 that can shrink by heating, polymer (A) having structural units derived from monomer A3 can help suppress the deviation of the optical film 3 at the ends.

[0125] Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of amino-containing monomers include N,N-dimethylaminoethyl (meth)acrylic acid and N,N-dimethylaminopropyl (meth)acrylic acid. 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, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, and mercaptoethyl(meth)acrylamide, etc.; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl lactam monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

[0126] Monomer A2 can be a multifunctional monomer. Examples of multifunctional monomers include hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate, as well as divinylbenzene. The most preferred multifunctional acrylates are 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

[0127] The total content of structural units derived from aromatic ring monomers, carboxyl monomers, amino monomers, amide monomers, and polyfunctional monomers in polymer (A) is preferably 20% by weight or less, more preferably 15% by weight or less, even more preferably 10% by weight or less, and particularly preferably 8% by weight or less. When polymer (A) contains such structural units, the total content is, for example, 0.01% by weight or more, and can be 1% by weight or more, 2% by weight or more, and even more preferably 3% by weight or more. Polymer (A) may also not contain these 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 (not containing such structural units).

[0128] Other examples of monomer A2 include nitrile-containing (meth)acrylates such as acrylic acid and (meth)acrylonitrile; epoxy-containing monomers such as glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate; sulfonic acid-containing monomers such as sodium vinyl sulfonate; phosphate-containing monomers; alicyclic hydrocarbon-containing (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0129] The total content of structural units from other monomers A2 in polymer (A) is, for example, 30% by weight or less, 10% by weight or less, and preferably 0% by weight (not having the structural unit).

[0130] Polymer (A) may have structural units derived from (meth)acrylic acid monomers with a glass transition temperature (Tgh) of -55°C or higher when forming a homopolymer, structural units derived from (meth)acrylic acid monomers with a Tgh of -40°C or higher, structural units derived from (meth)acrylic acid monomers with a Tgh of -30°C or higher, or structural units derived from (meth)acrylic acid monomers with a Tgh of -10°C or higher. Examples of the above structural units are structural units derived from monomer A3 and structural units derived from (meth)acrylic acid monomers having alkyl groups having 1 to 3 carbon atoms in the side chain. Polymer (A) may have at least one structural unit selected from structural units derived from monomer A3 and structural units derived from (meth)acrylic acid monomers having alkyl groups having 1 to 3 carbon atoms in the side chain. Polymer (A) having the above structural units can help improve the durability of the optical laminate 10.

[0131] Polymer (A) can be formed by polymerizing one or more of the aforementioned monomers using known methods. Monomers can be polymerized with portions of the monomer polymers. Polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy radiation polymerization. From the viewpoint of forming adhesive sheets with excellent optical transparency, solution polymerization and active energy radiation polymerization are preferred. Polymerization is preferably carried out under conditions that avoid contact between the monomers and / or portions of the polymer and oxygen; therefore, for example, polymerization can be carried out in an atmosphere of inactive gases such as nitrogen, or polymerization in an oxygen-isolated state such as through a resin film. The resulting polymer (A) can be any form, such as a random copolymer, block copolymer, or graft copolymer.

[0132] The polymerization system that forms polymer (A) may contain one or more polymerization initiators. The type of polymerization initiator can be selected according to the polymerization reaction, for example, it can be a thermal polymerization initiator or a photopolymerization initiator.

[0133] 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 examples listed above. A mixture of two or more solvents can be used.

[0134] The polymerization initiators used in solution polymerization include, for example, azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. Examples of peroxide polymerization initiators include benzoyl peroxide and tert-butyl maleate peroxide. Among these, the azo polymerization initiator disclosed in Japanese Patent Application Publication No. 2002-69411 is preferred. Examples of such azo polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, and 4,4'-azobis-4-cyanopentanoic acid. However, the polymerization initiator is not limited to the examples mentioned above. For example, the amount of azo polymerization initiator used is 0.05 to 0.5 parts by weight relative to 100 parts by weight of the total monomer, and can be 0.1 to 0.3 parts by weight.

[0135] The active energy rays used in active energy radiation polymerization include, for example, ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet radiation. Ultraviolet radiation is preferred. Polymerization based on ultraviolet irradiation is also called photopolymerization. Typically, the polymerization system of active energy radiation polymerization includes a photoinitiator. The polymerization conditions for active energy polymerization are not limited as long as polymer (A) can be formed.

[0136] Examples of photopolymerization initiators include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-keto alcohol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzoyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, and thioxanone photopolymerization initiators. However, photopolymerization initiators are not limited to the examples mentioned above.

[0137] 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-diphenylethane-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-(tert-butyl)dichloroacetophenone. Examples of α-ketool-based photopolymerization initiators include: 2-methyl-2-hydroxyphenylacetone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include: 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include: 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)oxime. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzoyl-based photopolymerization initiators include benzoyl. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of ketal-based photopolymerization initiators include benzoyldimethyl ketal. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0138] The amount of photopolymerization initiator relative to the total amount of monomers (100 parts by weight) is, for example, 0.01 to 1 part by weight, or 0.05 to 0.5 parts by weight.

[0139] The weight-average molecular weight (Mw) of polymer (A) is, for example, 1 million to 3 million, preferably 1.8 million to 3 million. By setting the weight-average molecular weight of polymer (A) to 1 million to 3 million, it has a tendency to suppress cracking of the adhesive sheet and to suppress the increase in viscosity and the occurrence of gelation. The weight-average molecular weight (Mw) of the polymer in this specification is a value determined based on GPC (gel permeation chromatography) (converted to polystyrene).

[0140] The content of polymer (A) in the adhesive composition (I), in terms of solids percentage, is, for example, 50% by weight or more, and can be 60% by weight or more, 70% by weight or more, 75% by weight or more, and more preferably 80% by weight or more. The upper limit of the content is, for example, 99% by weight or less, and can be 97% by weight or less, and more preferably 95% by weight or less.

[0141] (Antistatic agent)

[0142] The adhesive composition (I) may contain an antistatic agent. The antistatic agent helps reduce the surface resistivity of the adhesive sheet 1. Examples of antistatic agents are ionic compounds such as salts. The ionic compound may be an ionic liquid that is liquid at room temperature (25°C).

[0143] 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, with lithium ions being preferred. Inorganic cation salts can be lithium salts.

[0144] An example of anion contained in inorganic cation salts is Cl. - ,Br - I - AlCl4 - Al2Cl7 - BF4 - PF6 - ClO4 - NO3 - CH3COO - CF3COO - CH3SO3 - CF3SO3 - (CF3SO2)3C - AsF6 - SbF6 - NbF6 - TaF6 - (CN)2N - C4F9SO3 - C3F7COO - (CF3SO2)(CF3CO)N - -O3S(CF2)3SO3 - and the anions represented by the following general formulas (a) to (d).

[0145] (a) (C n F 2n+1 SO2)2N - (n is an integer from 1 to 10)

[0146] (b) CF2(C m F 2m SO2)2N - (m is an integer from 1 to 10)

[0147] (c) -O3S(CF2) l SO3 - (l is an integer from 1 to 10)

[0148] (d) (C p F 2p+1 SO2)N - (C q F 2q+1 SO2) (p and q are independent integers from 1 to 10)

[0149] The anion contained in the inorganic cation salt is preferably a fluorinated anion, more preferably a fluorinated imide anion. Examples of fluorinated imide anions are imide anions having a perfluoroalkyl group. More specific examples of fluorinated imide anions are (CF3SO2)(CF3CO)N. - The anion represented by the above general formula (a), (b) or (d) is preferably (CF3SO2)2N. - (C2F5SO2)2N - The (perfluoroalkyl sulfonyl)imide represented by general formula (a) is more preferably (CF3SO2)2N - The term refers to bis(trifluoromethanesulfonyl)imide. A preferred example of an inorganic cation salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0150] Examples of organic cationic salts are organic cation-anionic salts. Examples of cations contained in organic cationic salts are those containing organic groups. .organic Included Examples include nitrogen-containing Sulfur-containing Phosphorus Nitrogen-containing Sulfur-containing Nitrogen-containing Examples include ammonium cations and piperidine. cationic, pyrrolidine Cations, Pyridine Cations, cations with a pyrrolidine skeleton, cations with a pyrrole skeleton, imidazole Cations, Tetrahydropyrimidine Cations, dihydropyrimidines cationic, pyrazole Cationic, pyrazoline Cation. Contains sulfur. An example is the sulfonium cation. Containing phosphorus Examples are Cations. Organic. Examples of organic groups included are alkyl, alkoxy, and alkenyl groups. Preferred organic groups... Specific examples include tetraalkylammonium cations (e.g., tributylmethylammonium cations), alkylpiperidines cationic, alkylpyrrolidine cation.

[0151] Examples of anions contained in organic cationic salts are the same as those contained in inorganic cationic salts. A preferred example of an organic cationic salt is 1-ethyl-3-methylimidazolium. Bis(fluorosulfonyl)imide (EMI-FSI), trimethylbutylammonium bis(trifluoromethanesulfonyl)imide.

[0152] Antistatic agents can be used in combination with inorganic cationic salts and organic cationic salts. Preferably, antistatic agents contain organic cationic salts.

[0153] The amount of antistatic agent in the adhesive composition (I) relative to 100 parts by weight of polymer (A) is, for example, 0.5 parts by weight or more, and can be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, and more preferably 4 parts by weight or more. The upper limit of the amount relative to 100 parts by weight of polymer (A) is, for example, less than 30 parts by weight, and can be 20 parts by weight or less, 15 parts by weight or less, 12 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, and more preferably 6 parts by weight or less. By appropriately adjusting the amount of antistatic agent in the adhesive composition (I), the durability of the adhesive sheet 1 can be further improved.

[0154] The surface resistivity of adhesive sheet 1 can be 1.0 × 10⁻⁶. 13 For values ​​below Ω / □, the value can be 1.0 × 10⁻⁶. 12 Ω / □ or less, 1.0×10 11 Ω / □ or less, 1.0×10 10 Ω / □ or less, 1.0×10 9 Ω / □ or less, 8.0×10 8 Ω / □ or less, 5.0×10 8 Ω / □ or less, 3.0×10 8 Ω / □ or less, 2.0×10 8 Ω / □ or less, 1.0×10 8 Ω / □ or less, 8.0×10 7 Ω / □ or less, 5.0×10 7 Below Ω / □, it can be further increased to 2.0 × 10 7 Below Ω / □. The lower limit of surface resistivity is, for example, 1.0 × 10⁻⁶. 6 Ω / □ or higher, can be 1.0×10 7 Ω / □ or higher, further up to 1.0 × 10 8Ω / □ or higher. The adhesive sheet 1 may have a surface resistivity within the above range at a time point before the DIN test, or at a time point after the DIN test.

[0155] (Free radical scavenger)

[0156] The adhesive composition (I) may further include a free radical scavenger. Examples of free radical scavengers include various antioxidants such as hindered phenols, hindered amines, phosphites, phenols and thioethers, and mixtures of these systems.

[0157] Antioxidants include, for example, free radical chain inhibitors and peroxide decomposers.

[0158] Antioxidants can be at least one selected from hindered phenols, hindered amines, and phosphites.

[0159] Hindered phenolic antioxidants can have a structure in which at least one carbon atom adjacent to a carbon atom on an aromatic ring bonded to the OH group of the phenol is bonded with a tert-butyl group. Examples of hindered phenolic antioxidants are butylated hydroxytoluene (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).

[0160] Hindered amine antioxidants may have at least one hindered piperidine 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).

[0161] 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).

[0162] Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and high molecular weight phenolic antioxidants. Examples of monophenolic antioxidants include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and stearate β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Examples of bisphenol antioxidants include 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane. Examples of high molecular weight phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis(4'-hydroxy-3'-tert-butylphenyl)butyrate]ethylene glycol ester, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0163] Examples of thioether antioxidants are ADK STAB AO-503 and ADK STAB AO-26 (both trade names, manufactured by ADEKA).

[0164] The molecular weight of the free radical scavenger (e.g., antioxidant) can be 1000 or less, and can be 900 or less, 850 or less, 800 or less, 700 or less, 600 or less, 500 or less, 450 or less, and more preferably 400 or less. The lower limit of the molecular weight is, for example, 100 or more. According to the research of the inventors, free radical scavengers with molecular weights in the above range are particularly suitable for suppressing the amount of free radicals generated in adhesive sheets formed from the adhesive composition (I).

[0165] Free radical scavengers (such as antioxidants) can be liquid at 25°C.

[0166] The amount of free radical scavenger in the adhesive composition (I) relative to 100 parts by weight of polymer (A) is, for example, 0.1 parts by weight or more, and may be 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, and more preferably 0.5 parts by weight or more. The upper limit of the amount relative to 100 parts by weight of polymer (A) is, for example, 15 parts by weight or less, and may be 10 parts by weight or less, 7 parts by weight or less, 5 parts by weight or less, less than 5 parts by weight, 4 parts by weight or less, 3 parts by weight or less, and more preferably 2 parts by weight or less.

[0167] (additive)

[0168] The adhesive composition (I) may 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, reprocessability enhancers, softeners, polymerization inhibitors, rust inhibitors, inorganic fillers, organic fillers, powders, particles, and foils such as metal powders. The additives are formulated in a total amount, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 3 parts by weight or less, relative to 100 parts by weight of the polymer (A).

[0169] Examples of crosslinking agents include organic crosslinking agents and multifunctional metal chelates. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. Organic crosslinking agents and multifunctional metal chelates can also be used with any type of adhesive composition (I) in solvent-based and active energy radiation-cured types. When the adhesive composition (I) is solvent-based, peroxide crosslinking agents and isocyanate crosslinking agents are preferred. Peroxide crosslinking agents and isocyanate crosslinking agents can be used in combination. The adhesive composition (I) may contain isocyanate crosslinking agents, peroxide crosslinking agents, or both isocyanate crosslinking agents and peroxide crosslinking agents.

[0170] Examples of isocyanate crosslinking agents include aromatic isocyanate compounds such as toluene diisocyanate, chlorophenyl diisocyanate, diphenylmethane diisocyanate, phenyl dimethylene diisocyanate, and polymethylene polyphenyl isocyanate; alicyclic isocyanate compounds such as cyclopentene diisocyanate, cyclohexene diisocyanate, hydrogenated diphenylmethane diisocyanate, and isophorone diisocyanate; and aliphatic isocyanate compounds such as butene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate. Isocyanate crosslinking agents can be: compounds obtained by adding the above isocyanate compounds to polyols such as trimethylolpropane (adducts); compounds obtained by adding the above isocyanate compounds to polyols such as polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, and polyisoprene polyols; and derivatives of the above isocyanate compounds such as isocyanurates. Specific examples of derivatives include trimethylolpropane / toluene diisocyanate trimer adducts (e.g., Coronate L, manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate trimer adducts (e.g., Coronate HL, manufactured by Tosoh Corporation), and isocyanurates of hexamethylene diisocyanate (e.g., Coronate HX, manufactured by Tosoh Corporation).

[0171] When the adhesive composition (I) contains an isocyanate crosslinking agent, the amount of the agent relative to 100 parts by weight of the polymer (A) is, for example, 0.1 to 10 parts by weight, and may be 0.2 to 5 parts by weight, 0.25 to 3 parts by weight, 0.3 to 1 part by weight, or more preferably 0.3 to 0.5 parts by weight.

[0172] Examples of peroxide-based crosslinking agents include di(2-ethylhexyl) peroxide dicarbonate, di(4-tert-butylcyclohexyl) peroxide dicarbonate, disec-butyl peroxide dicarbonate, tert-butyl peroxynedecanoate, tert-hexyl peroxynepentanoate, dilauroyl peroxide, dioctanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, benzoyl peroxide, tert-butyl peroxyisobutyrate, and 1,1-di(tert-hexylperoxy)cyclohexane. Considering the superior crosslinking efficiency of peroxide-based crosslinking agents, benzoyl peroxide is a suitable candidate.

[0173] When the adhesive composition (I) contains a peroxide-based crosslinking agent, the amount of the agent relative to 100 parts by weight of the polymer (A) is, for example, 0.005 to 5 parts by weight, and may be 0.01 to 3 parts by weight, 0.05 to 2 parts by weight, 0.07 to 1 part by weight, 0.07 to 0.5 parts by weight, 0.07 to 0.3 parts by weight, and may further be 0.07 to 0.2 parts by weight.

[0174] Examples of silane coupling agents include epoxy-containing silane coupling agents such as 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; silane coupling agents containing (meth)acrylic acid groups such as 3-acryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltriethoxysilane; and silane coupling agents containing isocyanate groups such as 3-isocyanate-propyltriethoxysilane.

[0175] When the adhesive composition (I) contains a silane coupling agent, the amount of the agent relative to 100 parts by weight of the polymer (A) is, for example, 5 parts by weight or less, and may be 3 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, and more preferably 0.05 parts by weight or less. The adhesive composition (I) may not contain a silane coupling agent.

[0176] The adhesive composition (I) can be of various types, such as emulsion type, solvent type (solution type), active energy ray curable type (photocurable type), and hot melt type (hot melt type). From the viewpoint of forming an adhesive sheet with excellent durability, the adhesive composition (I) can be either solvent-based or active energy ray curable, or it can be solvent-based. Solvent-based adhesive compositions (I) may also not contain photocurable agents such as UV curing agents.

[0177] (Optical film)

[0178] Optical film 3 may include at least one selected from polarizing films and retardation films. Optical film 3 may include a polarizing film. Optical film 3 may be a laminated film including a polarizing film and / or a retardation film. Optical film 3 may be a glass film.

[0179] A polarizing film includes a polarizer. The polarizing film includes a polarizer and a protective film (transparent protective film) disposed on at least one side of the polarizer. The protective film is typically disposed in contact with the main surface of the polarizer. The polarizer may be disposed between two protective films. Protective films may also be disposed on both sides of the polarizer. The protective film may be a single layer or a stack of two or more layers.

[0180] There are no particular limitations on what constitutes a polarizer. Examples include: polarizers in which dichroic substances such as iodine and dichroic dyes are adsorbed onto hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, and then subjected to uniaxial stretching; and polyene-oriented films such as dehydrated polyvinyl alcohol products and dehydrochlorinated polyvinyl chloride products. Typically, a polarizer is formed from a polyvinyl alcohol film (which may contain partially saponified ethylene-vinyl acetate copolymer films) and dichroic substances such as iodine.

[0181] The thickness of the polarizer is not particularly limited; for example, it can be less than 80 μm, less than 50 μm, less than 30 μm, less than 25 μm, and further less than 20 μm. The lower limit of the polarizer's thickness is not particularly limited; for example, it can be greater than 1 μm, greater than 5 μm, greater than 10 μm, and further greater than 15 μm. Suppressing dimensional variations in thin polarizers (e.g., less than 20 μm thick) helps improve the durability of optical laminates, particularly their durability at high temperatures.

[0182] As materials 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 triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The protective film material can be thermosetting resins such as (meth)acrylic acid, urethane, acrylate urethane, epoxy, and silicone, or UV-curable resins. In the case where 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 bonded to one main surface of the polarizer via an adhesive, and a protective film made of thermosetting resin or UV-curable resin can be bonded to the other main surface of the polarizer. The protective film can contain one or more arbitrary additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0183] There is no particular limitation on the moisture permeability of the protective film; it can be up to 200 g / (m²). 2 ·day) or less, or 50g / (m 2The moisture content of the polarizing film is below 1000°C (days). In this case, it is possible to suppress the intrusion of moisture from the air into the interior of the polarizing film and to suppress changes in the moisture content of the polarizing film. As a result, it is possible to suppress the curling and dimensional changes of the polarizing film. In addition, when a protective film with low moisture permeability is disposed between the adhesive sheet 1 and the polarizing mirror, it is possible to help suppress the migration of free radicals from the adhesive sheet 1 at high temperatures. Examples of materials for forming a protective film with low moisture permeability include, for example, polyester polymers, polycarbonate polymers, aromatic ester polymers, amide polymers, olefin polymers, cyclic olefin polymers, (meth)acrylic polymers, and mixtures thereof.

[0184] The moisture permeability of the protective film can be determined according to the moisture permeability test (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 moisture permeability cup containing approximately 15g of calcium chloride. Place the moisture permeability cup in a thermostat set at 40°C and 92%RH for 24 hours to conduct the moisture permeability test. The moisture permeability of the protective film can be determined by measuring the increase in the weight of calcium chloride before and after the test.

[0185] The thickness of the protective film can be appropriately determined. Generally speaking, it is about 10~200μm, considering factors such as strength, operability, and thinness.

[0186] Polarizing lenses and protective films are typically bonded together using water-based adhesives. Examples of water-based adhesives include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, waterborne polyurethane, and waterborne polyester. Other adhesives besides those mentioned above include UV-curable adhesives and electron beam-curable adhesives. Electron beam-curable polarizer adhesives exhibit suitable adhesion to various protective films. The adhesive may contain metallic compound fillers.

[0187] In polarizing films, a phase retardation film can be formed on the polarizer to replace the protective film. Other protective films or phase retardation films can also be further applied to the protective film.

[0188] A polarizing film can be defined as a laminate containing a polarizing lens and whose layers are bonded together by an adhesive.

[0189] For the protective film, a hard coating can be applied to the surface opposite to the surface to which the polarizer is bonded, or treatments can be implemented for purposes such as anti-reflection, anti-adhesion, diffusion, and anti-glare.

[0190] The polarizing film can be a circularly polarizing film.

[0191] The curl diameter of the polarizing film evaluated by the following test method can be 3 mm or more, and can be 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 further can be 7.5 mm or more. A larger curl diameter means a polarizing film that is more able to suppress heat-induced curling. Furthermore, for the use of polarizing films with large curl diameters, for example, when an antistatic layer 2 is formed on the polarizing film, it is suitable to suppress curling while increasing the heating temperature during formation.

[0192] <Experimental Method>

[0193] Using the absorption axis of the polarizer as the longitudinal direction, a rectangular test piece 52 with a width of 10 mm and a length of 50 mm is prepared to be processed from the polarizing film 51. Next, one end 53a of the test piece 52 along its longitudinal direction is fixed to the surface of the evaluation piece 54 (see reference). Figure 2 (a) The upper surface of the test piece 52 is selected and fixed by means of heating and curling the other end 53b upwards. Adhesive tape 56 can be used for fixing, as long as the end 53a does not peel off from the evaluation piece 54 during the test; the fixing method is not limited. An example of adhesive tape 56 is polyimide tape. Next, the entire piece is heated at 105°C for 12 hours, causing the test piece 52 to curl from the other end 53b along its length. The inner diameter of the cylindrical portion 55 of the curled test piece 52 is determined as the curling diameter (see reference). Figure 2 (b)).

[0194] The degree of curling of the test piece 52 varies depending on the inherent thermal properties of the polarizing film 51. These inherent thermal properties vary according to the layer structure of the polarizing film 51, the composition, thickness, and other characteristics of each layer. An example of these inherent thermal properties is the bending moment M during heating, as described below.

[0195] The evaluation sheet 54 can be a sheet that will not be deformed by bending or other deformations that would hinder the evaluation of the curl diameter even after heating at 105°C for 12 hours. An example of the evaluation sheet 54 is a polystyrene sheet with a thickness of 5 mm.

[0196] The absolute value of the bending moment M of the polarizing film can be less than 1 × 10⁻⁶. 9 It can be 1×10 8 Below, 5×10 7 Below, 1×10 7 Below, 8×10 6 Below, 5×10 6 Below, 4×10 6 The following can be further extended to 3×10 6The following applies to the use of polarizing films with small bending moments M. For example, when an antistatic layer 2 is formed on the polarizing film, it is suitable to suppress curling while increasing the heating temperature during formation.

[0197] For the calculation method of bending moment M, refer to... Figure 3 Please provide an explanation. Figure 3 This is a cross-sectional view showing an example of polarizing film 51. Figure 3 The polarizing film 51 has a structure in which a polarizing lens 61 is sandwiched between a pair of transparent protective films 62 and 63. The polarizing lens 61 is made of PVA and has a thickness of 22 μm. The transparent protective film 62 is made of triacetyl cellulose (TAC) and has a thickness of 40 μm. The transparent protective film 63 is made of acrylic resin and has a thickness of 20 μm. The symbol 51C is an imaginary surface located at the center of the thickness direction in the polarizing film 51 (hereinafter referred to as the center surface 51C). The symbols 61C, 62C, and 63C are respectively imaginary surfaces located at the center of the thickness direction in each layer (hereinafter referred to as center surfaces 61C, 62C, and 63C).

[0198] For each layer contained in 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 polarizer is defined by the formula: EtαΔT. The expansion force P of the polarizer is defined by the formula: EtβΔT. E is the storage 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 between heating and room temperature (23°C) (unit:°C), and β is the rate of dimensional change of the polarizer due to heating (105°C and 500 hours) (unit: %). The storage modulus E is a value obtained through tensile testing. The tensile test is performed on a dumbbell-shaped test piece at a tensile speed of 300 mm / min. The E of the polarizer 61 is the value in the direction of the slow axis. The coefficient of thermal expansion α is a value obtained through thermomechanical analysis (TMA). TMA was performed under the following conditions: the measurement temperature was set to -40 to 85°C, the sample size was set to 5 mm in width, and the clamp spacing was set to 20 mm. Considering the heating temperature during the formation of the antistatic layer 2, ΔT was set to 67 (=90-23)°C. It should be noted that the polarizer 61 typically contracts along the slow axis due to heating, therefore β and the expansion force P 61 It is usually a negative value.

[0199] The dimensional change rate β of the polarizer can be determined by processing a polarizer with an adhesive layer into a size of 10cm × 10cm, attaching the test piece to a glass plate, and measuring the dimensional change of the test piece before and after a heating test in an oven maintained at 105°C for 500 hours. The direction of extension of one side of the test piece is defined as the direction of the absorption axis of the polarizer. The dimensional change rate β is expressed by the formula: Dimensional change rate β = (Wmin Calculated by -10) / 10×100(%). min It is the length of the shortest side of the test piece after the heating test. A polarizer with an adhesive layer can be prepared as described below.

[0200] * A monomer mixture containing 99 parts by weight of butyl acrylate and 1 part by weight of 4-hydroxybutyl acrylate was added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet, and cooler. Next, 0.1 parts by weight of 2,2'-azobisisobutyronitrile (2,2'-Azobisisobutyronitrile), acting as a polymerization initiator, and 100 parts by weight of ethyl acetate were added together with 100 parts by weight of the monomer mixture. The mixture was then slowly stirred, and nitrogen was introduced for nitrogen purging. The liquid temperature in the flask was maintained at approximately 55°C, and the polymerization reaction was carried out for 8 hours to prepare 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 components of the prepared solution, 0.03 parts by weight of trimethylolpropane / phenylenediamine diisocyanate adduct (e.g., Takenate D110N manufactured by Tosoh Corporation), 0.3 parts by weight of benzoyl peroxide, and 0.2 parts by weight of an epoxy-containing silane coupling agent (e.g., KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) were added to prepare an adhesive composition. The prepared adhesive composition was then dried at 155°C for 1 minute to form an adhesive layer with a thickness of 20 μm. A polarizing lens was bonded to the prepared adhesive layer to obtain a polarizing film with the adhesive layer.

[0201] Furthermore, for each layer included in the polarizing film 51, the distance d(d) from the center plane 51C of the polarizing film 51 to the center planes 61C, 62C, and 63C of each layer can be determined. 61 d 62 d 63 In this context, the unit of distance d is set to μm, and the direction from one principal surface 64A of the polarizing film 51 to the other principal surface 64B is set to negative, thereby determining the sign of distance d. Figure 3 In the example, the distance d 62 If negative, the distance d 61 d 63 It is positive. The bending moment M can be determined as the sum of the products of the expansion forces P and d exhibited by each layer constituting the polarizing film 51. Figure 3 In the example, the bending moment M=P 61 ×d 61 +P 62 ×d 62 +P 63 ×d 63 .

[0202] The polarizing film 51 typically has a multilayer structure including a polarizing lens. The bending moment M can be calculated similarly even when the layer structure and materials of each layer of the polarizing film 51 differ. It should be noted that the expansion force P generated by the hard coating is usually small and can be ignored in the calculation of the bending moment M.

[0203] As a retardation film, films obtained by stretching a polymer film or films that orient and immobilize liquid crystal materials can be used. Retardation films, for example, exhibit birefringence in the in-plane and / or thickness directions.

[0204] Examples of phase retardation films include: anti-reflection phase retardation films (see Japanese Patent Application Publication No. 2012-133303

[0221] ,

[0222] ,

[0228] ), phase retardation films for field-of-view compensation (see Japanese Patent Application Publication No. 2012-133303

[0225] ,

[0226] ), and tilt-oriented phase retardation films for field-of-view compensation (see Japanese Patent Application Publication No. 2012-133303

[0227] ).

[0205] As a phase retardation film, it is sufficient to have the above-mentioned functions. For example, there are no particular limitations on the phase difference value, configuration angle, three-dimensional birefringence, whether it is a single layer or a multilayer, and known phase retardation films can be used.

[0206] The thickness of the phase retardation film is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 1 to 9 μm, and particularly preferably 3 to 8 μm.

[0207] Phase retardation films, for example, consist of two layers of liquid crystal material after alignment and immobilization: a quarter-wavelength plate and a half-wavelength plate.

[0208] (Surface resistivity of optical laminates)

[0209] The optical laminate 10 may sequentially comprise an adhesive sheet 1, an antistatic layer 2, and an optical film 3, and satisfy the following equation (4). Wherein, C in equation (4) is the surface resistivity (unit: Ω / □) of the main surface 5 of the adhesive sheet 1 opposite to the antistatic layer 2 in the optical laminate 10. D in equation (4) is the surface resistivity (unit: Ω / □) of the main surface 5 of the adhesive sheet 1 opposite to the antistatic layer 2 in the optical laminate 10 after DIN testing (refer to [reference] for the main surface 5). Figure 1 ).

[0210] -1≤logD-logC≤2 (4)

[0211] According to the researchers' findings, changes in the resistance of the optical laminate 10 due to exposure to harsh environments such as automotive applications can also cause display malfunctions. Furthermore, in image display devices incorporating touch sensors, changes in the resistance of the optical laminate 10 can also cause malfunctions of the touch sensor.

[0212] The lower limit of logD-logC in equation (4) can be above -0.9, above -0.8, above -0.7, above -0.6, above -0.5, above -0.4, above -0.35, above -0.3, above -0.25, above -0.2, above -0.15, above -0.1, and further can be above -0.05. The upper limit of logD-logC is below 1.9, below 1.8, below 1.7, below 1.6, below 1.5, below 1.4, below 1.3, below 1.2, below 1.1, below 1.0, below 0.9, below 0.8, below 0.7, below 0.6, below 0.5, below 0.4, below 0.3, below 0.25, below 0.2, below 0.15, below 0.1, and further can be below 0.05.

[0213] The logD-logC in equation (4) varies depending on the composition of the adhesive sheet 1, the composition of the antistatic layer 2, and the formation method. Furthermore, if the optical laminate 10 includes an antistatic layer in addition to the antistatic layer 2, it will vary depending on the composition of that layer. Examples of the composition of the adhesive sheet 1 include the type and content of monomers used in its formation, and the type and content of additives such as antistatic agents included in the adhesive sheet 1. Examples of the composition of the antistatic layer 2 include the type and content of conductive materials, and the type, content, and properties of materials other than conductive materials. Examples of materials other than conductive materials include adhesive resins and leveling agents. Examples of the formation method of the antistatic layer 2 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 the formation conditions include the drying temperature of the coating liquid.

[0214] The surface resistivity C (surface resistivity before DIN test) of optical laminate 10 is, for example, 1.0 × 10⁻⁶. 12 For values ​​below Ω / □, the value can be 1.0 × 10⁻⁶. 11 Ω / □ or less, 7.0×10 10 Ω / □ or less, 5.0×10 10 Ω / □ or less, 3.0×10 10 Ω / □ or less, 1.0×10 10 Ω / □ or less, 7.0×10 9 Ω / □ or less, 5.0×10 9 Ω / □ or less, 3.0×109 Ω / □ or less, 1.0×10 9 Ω / □ or less, 9.0×10 8 Ω / □ or less, 8.0×10 8 Ω / □ or less, 7.0×10 8 Ω / □ or less, 6.0×10 8 Ω / □ or less, 5.0×10 8 Ω / □ or less, 4.0×10 8 Ω / □ or less, 3.0×10 8 Ω / □ or less, 2.0×10 8 Ω / □ or less, less than 2.0 × 10 8 Ω / □, 1.5×10 8 Ω / □ or less, 1.0×10 8 Ω / □ or less, 9.0×10 7 Ω / □ or less, 8.0×10 7 Below Ω / □, it can be further increased to 7.5 × 10 7 Below Ω / □. The lower limit of surface resistivity C is, for example, 1.0 × 10⁻⁶. 6 Ω / □ or higher, can be 5.0 × 10 6 Ω / □ or more, 1.0×10 7 Ω / □ or more, 2.0×10 7 Ω / □ or more, 3.0×10 7 Ω / □ or higher, 4.0×10 7 Ω / □ or above, 5.0×10 7 Ω / □ or higher, further up to 6.0 × 10 7 Ω / □ and above.

[0215] Examples of surface resistivity D (surface resistivity after DIN test) of optical laminate 10 in the optional range are the same as examples of surface resistivity C in the optional range.

[0216] Surface resistivity D can be the same as or greater than surface resistivity C. In other words, the relationship between surface resistivity D and surface resistivity C can be expressed by the equation: surface resistivity D ≥ surface resistivity C, or by the equation: surface resistivity D = surface resistivity C.

[0217] Surface resistivity C and D can be determined by measuring the surface resistivity of the main surface 5 of the adhesive sheet 1 in the optical laminate 10. The surface resistivity can be measured using a high-resistivity resistivity meter (for example, the Hiresta series manufactured by Mitsubishi Chemical Analytech) according to the method specified in JIS K6911:1995. The surface resistivity C and D are measured under the conditions of an applied voltage of 500V for 30 seconds and an ambient temperature of 25±3℃.

[0218] Considering that changes in the resistance of the optical laminate 10 due to exposure to harsh environments such as automotive applications could cause display malfunctions and touch sensor malfunctions, this embodiment discloses an optical laminate as shown below. That is, the optical laminate of this embodiment, which differs from the one described above, can be an optical laminate that sequentially includes an adhesive sheet, an antistatic layer, and an optical film, and satisfies the following formula (4).

[0219] -1≤logD-logC≤2 (4)

[0220] In formula (4), C is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that is opposite to the antistatic layer, and D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that is opposite to the antistatic layer, after passing the weather resistance test (test conditions: Z-IN1) specified by German industrial standard DIN75220.

[0221] [Fabrication of Optical Laminates]

[0222] The optical laminate 10 can be manufactured, for example, by fabricating a first laminate L1 formed of an optical film 3 and an antistatic layer 2, fabricating a second laminate L2 formed of a substrate and an adhesive sheet 1, and bonding the adhesive sheet 1 of the second laminate L2 to the antistatic layer 2 of the first laminate L1. However, the method of manufacturing the optical laminate 10 is not limited to this example.

[0223] (Preparation method of antistatic layer 2 and first laminate L1)

[0224] First, a solution or dispersion of the conductive material is prepared. Examples of solvents for the solution or dispersion include water and organic solvents. The organic solvent can be water-soluble. The solvent can be a single solvent or a mixture containing two or more solvents. Examples of mixed solvents include a solvent containing water and a water-soluble organic solvent. Examples of water-soluble organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, sec-pentanol, tert-pentanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol. Isopropanol (IPA) can also be a water-soluble organic solvent. According to the researchers of the present invention, combining the conductive material with a single solvent can help suppress the change in surface resistivity of the antistatic layer 2 before and after the DIN test. The single solvent is preferably water. In addition, according to research, the use of a single solvent, especially water, may help improve the uniformity of CNTs in the antistatic layer 2.

[0225] Next, a solution or dispersion of conductive material is applied as a coating liquid to the surface of the optical film 3. By drying the resulting coating film, an antistatic layer 2 is formed on the optical film 3. Thus, a first laminate L1 formed by the optical film 3 and the antistatic layer 2 is obtained. Heating can be used in combination during drying. The drying temperature when using heating in combination 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 more preferably 130°C or higher. The upper limit of the drying temperature is, for example, 160°C or lower. According to the researchers of the present invention, a drying temperature of 70°C or higher, preferably 80°C or higher, and more preferably 90°C or higher, can help suppress changes in the surface resistivity of the antistatic layer 2 before and after the DIN test. Furthermore, according to research, a drying temperature of 70°C or higher, preferably 80°C or higher, and more preferably 90°C or higher may help improve the uniformity of CNTs in the antistatic layer 2. On the other hand, if the drying temperature during the formation of the antistatic layer 2 becomes too high, curling of the optical laminate 2 may sometimes occur. To suppress curling, an upper limit for the drying temperature can be appropriately set. The upper limit will vary depending on the composition of the optical film 3, for example, below 160°C, and can be below 150°C, below 140°C, below 130°C, less than 130°C, below 125°C, below 120°C, below 115°C, and further below 110°C.

[0226] In considering the fabrication of the preferred antistatic layer 2, this embodiment discloses the manufacturing method shown below. Specifically, the manufacturing method of the antistatic layer 2 in this embodiment includes drying a coating film containing a conductive material and a single solvent (e.g., a solution or dispersion) to form the antistatic layer 2. Examples of preferred methods for the conductive material and the single solvent are described above. The coating film may, for example, be formed on the surface of a substrate. A release film may, for example, be used in the substrate. The antistatic layer 2 formed on the release film may, for example, be transferred onto an optical film. The substrate may be an optical film. The coating liquid may contain materials other than the conductive material, such as an adhesive resin. Examples of preferred methods for the adhesive resin are described above. The coating liquid may contain a leveling agent. Preferably, the content of the leveling agent in the coating liquid is low, as exemplified above in the description of the antistatic layer 2. The coating liquid may substantially not contain a leveling agent. Preferred examples of the drying temperature of the coating film are described above. The drying temperature may be 70°C or higher and lower than 130°C.

[0227] Furthermore, the method for manufacturing the antistatic layer 2 in this embodiment includes: drying a coating film containing a coating liquid containing a conductive material at a temperature of 70°C or higher and lower than 130°C to form the antistatic layer 2. The preferred drying temperature of the coating film is as described above. Examples of preferred methods regarding the conductive material are as described above. The coating film may, for example, be formed on the surface of a substrate. The substrate may, for example, be a release film. The antistatic layer 2 formed on the release film may, for example, be transferred onto an optical film. The substrate may be an optical film. The coating liquid may contain materials other than the conductive material, such as an adhesive resin. Examples of preferred methods regarding the adhesive resin are as described above. The coating liquid may contain a leveling agent. The leveling agent content in the coating liquid is preferably low, as exemplified above in the description of the antistatic layer 2. The coating liquid may substantially not contain a leveling agent. The solvent contained in the coating liquid may be a single solvent. Examples of preferred methods regarding a single solvent are as described above.

[0228] The method for manufacturing the optical laminate of this embodiment is a method for manufacturing an optical laminate comprising an adhesive sheet, an antistatic layer and an optical film. The method includes forming the antistatic layer by the method for manufacturing the antistatic layer 2 of this embodiment described above.

[0229] (Preparation of the second laminate L2)

[0230] Adhesive sheet 1 is formed from adhesive composition (I). Adhesive sheet 1 may, for example, comprise a crosslinked polymer of (meth)acrylic acid. Adhesive sheet 1 may be formed from adhesive composition (I) by the following method.

[0231] The adhesive sheet 1 can be formed, for example, by applying an adhesive composition (I) to a substrate to form a coated film; and drying the resulting coated film. Thus, a second laminate L2 formed from the substrate and the adhesive sheet 1 can be obtained.

[0232] As a substrate, a release film can be used, for example. The adhesive sheet 1 formed on the release film can be transferred onto the optical film, for example. The substrate can be an optical film.

[0233] For the release film, it can be used as a release film after the adhesive sheet 1 is transferred onto the antistatic layer 2 and before the adhesive sheet 1 is actually used. In this case, process simplification can be achieved.

[0234] Examples of materials that can be used as release films include porous materials such as plastic films, paper, cloth, and non-woven fabrics; suitable thin layers such as mesh, foam sheets, metal foils and their laminates; and plastic films are preferred from the viewpoint of excellent surface smoothness.

[0235] As for plastic films, there are no particular limitations. 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.

[0236] The thickness of the release film is typically 5–200 μm, preferably around 5–100 μm. Release treatment based on release agents such as organosilicon, fluorine, or long-chain alkyl compounds can be applied to the release film. Various antistatic treatments, such as coating, mixing, or vapor deposition, can also be applied to the release film using release agents based on fatty acid amides, silica powder, etc.

[0237] A solution (adhesive solution) containing adhesive composition (I) can be coated onto a substrate. The solid content concentration of the adhesive solution is, for example, 5 to 50% by weight, preferably 10 to 40% by weight. The adhesive solution can be prepared by appropriately adding the same solvent or a different solvent as the polymerization solvent to the adhesive composition (I) according to the polymerization method of the (meth)acrylic polymer (A).

[0238] Various methods can be used to coat the adhesive composition (I) onto the substrate, such as roller coating, contact roller coating, gravure coating, reverse coating, roller brush coating, spray coating, dip roller coating, bar coating, doctor blade coating, air knife coating, curtain coating, lip coating, and extrusion coating using a die coater. The coating amount of the adhesive composition (I) can be appropriately adjusted according to the thickness of the target adhesive sheet 1.

[0239] The coated film is cured by drying to form adhesive sheet 1. The drying temperature of the coated film is, for example, below 130°C, preferably below 125°C, more preferably below 120°C, further preferably below 110°C, and particularly preferably below 100°C. The drying temperature of the coated film can be above 60°C, or above 80°C. A drying temperature above 60°C, for example, can help improve the cohesiveness of adhesive sheet 1 by allowing the reaction of the isocyanate crosslinking agent to proceed smoothly. A drying temperature below 130°C, for example, can help improve the transparency of adhesive sheet 1 by appropriately adjusting the reaction rate of the isocyanate crosslinking agent.

[0240] The drying time of the coating film can be appropriately adjusted according to the composition of the adhesive composition (I), preferably 30 seconds to 300 seconds, more preferably 40 seconds to 240 seconds, and particularly preferably 60 seconds to 180 seconds.

[0241] 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. In addition, appropriately adjusting the thickness of the adhesive sheet 1 can help prevent the adhesive sheet 1 from peeling off from the adhered objects such as glass and image display devices.

[0242] Next, the adhesive sheet 1 of the second laminate L2 is bonded to the antistatic layer 2 of the first laminate L1. Thus, a laminate formed by the optical film 3, the antistatic layer 2, the adhesive sheet 1, and the substrate can be obtained.

[0243] Figure 4 This is a cross-sectional view schematically showing another example of the optical laminate of this embodiment. Figure 4 The optical laminate 10 (10B) has a laminated structure in which a release liner 4, an adhesive sheet 1, an antistatic layer 2, and an optical film 3 are sequentially stacked. The optical laminate 10B can be used by attaching it to, for example, an image display unit after the release liner 4 has been peeled off.

[0244] Examples of materials that can be used as the constituent material of the release liner 4 include: plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film; porous materials such as paper, cloth, and nonwoven fabric; and suitable thin layers such as mesh, foam sheets, metal foil, and their laminates. From the viewpoint of excellent surface smoothness, plastic film is preferred.

[0245] As for the plastic film, any film that can protect the adhesive sheet 1 is acceptable, without any particular limitation. 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.

[0246] The thickness of the release liner 4 is typically 5~200μm, preferably around 5~100μm. Various treatments, such as demolding, anti-fouling, and antistatic treatments, can be applied to the release liner 4 as needed. For demolding and anti-fouling treatments, various release agents such as organosilicon, fluorine, long-chain alkyl, and fatty acid amides, as well as silica powder and other particles, can be used. Antistatic treatment can be applied using coating, compounding, or vapor deposition methods. To improve the peelability of the adhesive sheet 1, it is particularly preferable to apply a release treatment to the surface of the release liner 4.

[0247] The release film used in the formation of adhesive sheet 1 can be used as release liner 4.

[0248] The optical laminate of this embodiment may have other layers and / or films besides those described above.

[0249] The optical laminate of this embodiment can be manufactured, for example, as a wound body formed by winding a strip of optical laminate, or as a monolithic optical laminate, thereby facilitating circulation and storage. The optical laminate of this embodiment is suitable for image display devices used in environments particularly prone to static electricity generation, especially automotive displays. Examples of automotive displays include car navigation system panels, car dashboard panels, and rearview mirror displays. A car dashboard panel displays information such as vehicle speed and engine RPM.

[0250] [Image Display Panel]

[0251] An example of the image display panel of this embodiment is shown below. Figure 5 . Figure 5 The image display panel 11 (11A) includes an optical laminate 10A and further includes an image display unit 30A. The optical laminate 10A is attached to the image display unit 30A via an adhesive sheet 1.

[0252] 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 respectively connected to the first transparent substrate 31 and the second transparent substrate 33. The adhesive sheet 1 is connected to the first transparent substrate 31.

[0253] The image forming layer 32 is, for example, a liquid crystal layer containing homogeneously oriented liquid crystal molecules in the absence of an electric field. Liquid crystal layers containing these liquid crystal molecules are suitable for IPS (In-Plane-Switching) systems. However, liquid crystal layers can also be used for TN (Twisted Nematic), STN (Super Twisted Nematic), π-type, VA (Vertical Alignment), and other similar systems. The image forming layer 32 can be an EL (Elastic Elastic Discharge) layer.

[0254] The thickness of the image forming layer 32 is, for example, 1.5 μm to 4 μm.

[0255] Materials used for the first transparent substrate 31 and the second transparent substrate 33 include, for example, glass and polymers. Polymers constituting the transparent substrates include, for example, polyethylene terephthalate, polycyclic olefins, and polycarbonate. The thickness of the transparent substrate made of glass is, for example, 0.1 mm to 1 mm. The thickness of the transparent substrate made of polymer is, for example, 10 μm to 200 μm.

[0256] The image display unit 30A may further include layers other than the image forming layer 32, the first transparent substrate 31, and the second transparent substrate 33. Examples of such other layers include color filters, easy-to-adhere layers, and hard coatings. The color filters, for example, are positioned closer to the visible side than the image forming layer 32, preferably between the first transparent substrate 31 and the adhesive sheet 1. The easy-to-adhere layers and hard coatings are, for example, disposed on the surfaces of the first transparent substrate 31 and / or the second transparent substrate 33.

[0257] The image display panel 11A may further include other components besides the optical laminate 10A and the image display unit 30A. For example, the image display panel 11A may further include a conductive structure (not shown) electrically connected to the side of the optical laminate 10A. By grounding the conductive structure, static electricity-induced charging of the optical laminate 10A can be easily suppressed. 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 of ​​the side of the optical laminate 10A covered by the conductive structure to the area of ​​the entire side of the optical laminate 10A is, for example, 1% or more, preferably 3% or more.

[0258] Materials used for the conductive structure include, for example, conductive pastes made of metals such as silver and gold; conductive adhesives; and other conductive materials. The conductive structure can be wiring extending from the side of the optical laminate 10A.

[0259] The image display panel 11A may further include other optical films besides the optical film 3. Examples of other optical films include polarizing films, reflective films, anti-transmission films, field-angle compensation films, brightness enhancement films, and other films used in image display devices. The image display panel 11A may include one or more other optical films.

[0260] When the other optical film is a polarizing film, this polarizing film can be bonded to the second transparent substrate 33 of the image display unit 30A. The polarizing film, as another optical film, can have the same configuration as the polarizing film, which is optical film 3. For the polarizing film, which is optical film 3, and the polarizing film, which is another optical film, the transmission axis (or absorption axis) of the polarizer can be orthogonal to each other. An adhesive sheet can be used for bonding with the second transparent substrate 33. This adhesive sheet can be adhesive sheet 1. The thickness of the adhesive sheet used for bonding with the second transparent substrate 33 is, for example, 1~100μm, 2~50μm, 2~40μm, and more preferably 5~35μm.

[0261] Another example of the image display panel of this embodiment is shown below. Figure 6 In addition to having a conductive layer 40 disposed between the optical laminate 10A and the image display unit 30A, Figure 6 The image display panel 11 (11B) has the same configuration as the image display panel 11A. However, in this embodiment, the image display panel may not include the conductive layer 40. The absence of the conductive layer 40 helps suppress the reflectivity of the image display panel, in other words, it helps improve the visual legibility of the image display device. In the image display panel 11A without the conductive layer 40, a conductive portion (the conductive structure described above) adjacent to the adhesive sheet 1 is preferably provided. Conductive silver paste can be used, for example, in the conductive portion.

[0262] The conductive layer 40 may contain, for example, a conductive agent. Known materials such as metal oxides and conductive polymers may be used as the conductive agent. The thickness of the conductive layer 40 is, for example, 5 nm to 180 nm. The surface resistivity of the conductive layer 40 is, for example, 1.0 × 10⁻⁶. 6 Ω / □~1.0×10 10 Ω / □, preferably 1.0 × 10 7 Ω / □~1.0×10 9 Ω / □.

[0263] The image display panel of this embodiment can have built-in touch sensing functionality. An example of an image display panel with built-in touch sensing functionality is shown below. Figure 7 . Figure 7The image display panel 11 (11C) has the same configuration as the image display panel 11A, except that the image display unit 30B further 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 in-cell image display panel, and the image display unit 30B is a so-called in-cell image display unit. However, the touch sensing electrode 35 may also be disposed closer to the visible side than the first transparent substrate 31. In other words, the image display panel 11C can be a so-called on-cell image display panel, and the image display unit 30B can be a so-called on-cell image display unit.

[0264] The touch sensing electrode unit 35 includes a touch sensor electrode 36 and a touch driving electrode 37. The touch sensor electrode 36 is a (receiving) electrode for detecting touch. The touch sensor electrode 36 and the touch driving electrode 37 can each be formed independently of various patterns. For example, when the image display unit 30B is flat, the touch sensor electrode 36 and the touch driving electrode 37 can be independently arranged along the X-axis and Y-axis directions, respectively, forming a pattern where they intersect at right angles. Figure 7 In the touch sensing electrode section 35, the touch sensor electrode 36 is positioned closer to the visible side than the touch driving electrode 37. The touch driving electrode 37 may also be positioned closer to the visible side than the touch sensor electrode 36. In the touch sensing electrode section 35, the touch sensor electrode 36 and the touch driving electrode 37 can be integrated.

[0265] Figure 7 The touch sensing electrode portion 35 is disposed between the image forming layer 32 and the first transparent substrate 31 (on the visible side of the image forming layer 32). However, the touch sensing electrode portion 35 may also be disposed between the image forming layer 32 and the second transparent substrate 33 (on the side of the image forming layer 32 closer to the lighting system).

[0266] 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.

[0267] The driving electrode (touch driving electrode 37, or an electrode formed by integrating touch sensor electrode 36 and touch driving electrode 37) in the touch sensing electrode section 35 can also serve as the common electrode for controlling the image forming layer 32.

[0268] The touch sensor electrode 36 (capacitive sensor), touch driving electrode 37, or electrodes formed by integrating them into the touch sensing electrode section 35 function as a transparent conductive layer. The material of the transparent conductive layer is not particularly limited, and examples 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. Specific examples of oxides include indium oxide, tin oxide, titanium oxide, cadmium oxide, and mixtures thereof. The material of the transparent conductive layer can be a metal compound such as copper iodide. The preferred material of the transparent conductive layer is indium oxide (ITO) containing tin oxide, tin oxide containing antimony, etc., and ITO is particularly preferred. When the material of the transparent conductive layer is ITO, it is preferable that the indium oxide content in the transparent conductive layer is 80-99% by weight, and the tin oxide content is 1-20% by weight.

[0269] The electrodes constituting the touch sensing electrode section 35 (touch sensor electrode 36, touch driving electrode 37, or electrodes formed by integrating them) can be formed in the form of a transparent electrode pattern between the first transparent substrate 31 and the second transparent substrate 33 using conventional methods. The transparent electrode pattern is electrically connected, for example, to leads formed at the ends of the transparent substrates. These leads are connected, for example, to a controller IC. The shape of the transparent electrode pattern can be any shape, such as a comb shape, stripe shape, or diamond shape, depending on the application. The thickness of the transparent electrode pattern is, for example, 10 nm to 100 nm. The width of the transparent electrode pattern is, for example, 0.1 mm to 5 mm.

[0270] [Implementation of the Image Display Device]

[0271] The image display device of this embodiment includes, for example, an image display panel 11A and an illumination system. It should be noted that an image display panel 11B or an image display panel 11C may also be used instead of the image display panel 11A. In the image display device, the image display panel 11A is, for example, positioned closer to the viewing side than the illumination system. The illumination system, for example, has a backlight or a reflector, which illuminates the image display panel 11A.

[0272] The image display device in 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 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 used as an automotive display.

[0273] Example

[0274] The present invention will be further described in detail below through embodiments. The present invention is not limited to the embodiments shown below.

[0275] [Fabrication of the first laminate L1 formed by the antistatic layer and polarizing film]

[0276] <Preparation of coating solution for forming antistatic layer>

[0277] (Applying solutions A1~A6)

[0278] 0.05 parts by weight of CNTs (manufactured by OCSiAL, TUBALL 01RW02, monolayer) with an average length of 5 μm and a diameter of approximately 1.6 nm, 0.6 parts by weight of dispersant (manufactured by BASF, trade name: Pluronic F-108, HLB: 24 or higher), 30 parts by weight of ethanol, and 70 parts by weight of pure water were added to a glass beaker. The mixture was dispersed using an ultrasonic homogenizer at 50 W and 30 kHz for 30 minutes, yielding a CNT dispersion with a solid content of 1.0% by weight. Next, the obtained CNT dispersion, adhesive resin, and leveling agent (added as needed) were mixed according to the solid content weight ratios shown in Table 1 below. The mixture was then diluted with pure water or a mixture of pure water and isopropanol (IPA) (volume ratio 1:1) to achieve a solid content of 2% by weight, preparing coating solutions A1 to A6. The CNTs had a length between 3 μm and 300 μm. The adhesive resins used were Jurymer FC-80 from Toa Synthetic (listed as acrylic acid in Table 1, 30% solids by weight, Tg 50°C) or Superflex 650 from Daiichi Kogyo Pharmaceutical (listed as urethane in Table 1, 26% solids by weight, Tg -15°C). The leveling agent used was Emulmin 240 from Sanyo Chemical Industry, a polyether-based leveling agent. For coating liquid A7, the types of adhesive resin and leveling agent were the same.

[0279] (Applying solution A7)

[0280] 0.08 parts by weight of CNTs (Zeon Nanotechnology, ZEONANO SG101, monolayer) with an average length of 300 μm and a diameter of approximately 4 nm, 0.7 parts by weight of dispersant (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 added to a glass beaker. The mixture was dispersed using an ultrasonic homogenizer at 50 W and 30 kHz for 30 minutes, yielding a CNT dispersion with a solid content of 1.0% by weight. Next, the obtained CNT dispersion, adhesive resin, and leveling agent were mixed according to the solid content weight ratios shown in Table 1 below, and then diluted with pure water to achieve a solid content of 2% by weight, thus preparing coating solution A7.

[0281] (Applying solution A8)

[0282] The mixture contains 14.3 parts by weight of a thiophene polymer liquid (PEDOT / PSS-NH4), 1 part by weight of adhesive resin solution A (Superflex 210 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., containing urethane resin, with a solid content of 35% by weight), and adhesive resin solution B (EPOCROS WS-70 manufactured by Nippon Shokubai Co., Ltd., containing... A coating solution A8 with a solid content of 1.5% by weight was obtained by mixing 4 parts by weight of an acrylic resin with a solid content of 25% by weight, triethylene glycol, and water. The thiophene polymer-containing liquid was prepared by neutralizing an aqueous dispersion (manufactured by Heraeus, Clevios P) containing poly(3,4-ethylenedioxythiophene) (PEDOT) and sodium polystyrene sulfonate (PSS) with ammonia water to achieve a solid content of 1% by weight. Triethylene glycol was mixed in such a way that the content in coating solution A8 reached 3% by weight. Coating solution A8 contained 0.14% by weight of thiophene polymer, 0.36% by weight of urethane resin binder, and 1.0% by weight of acrylic resin binder.

[0283] (Applying solution A9~A11)

[0284] As the adhesive resin, Jurymer FC-80 (listed as acrylic acid in Table 1, solid content 30% by weight, Tg 50℃) manufactured by Toa Synthetic and Superflex 650 (listed as urethane in Table 1, solid content 26% by weight, Tg -15℃) manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd. were mixed together. In addition, coating solutions A9 to A11 were prepared in the same manner as coating solutions A1 to A6. The mixing ratio of Jurymer FC-80 and Superflex 650 was adjusted to achieve the solid content ratio shown in Table 1 below.

[0285] The results for each topical solution are summarized in Table 1.

[0286]

[0287] <Fabrication of Polarizing Film>

[0288] (Making of protective film A with a hard coating)

[0289] A resin solution (DIC, trade name: UNIDIC 17-806, solids concentration: 80%) containing a UV-curable resin monomer or oligomer with urethane acrylate as the main component was prepared by dissolving it in butyl acetate. Next, 5 parts by weight of a photopolymerization initiator (BASF, trade name: IRGACURE907) and 0.1 parts by weight of a leveling agent (DIC, trade name: GRANDIC PC4100) were added relative to 100 parts by weight of the solids in the resin solution. Then, cyclopentanone and propylene glycol monomethyl ether were added to the resin solution at a weight ratio of 45:55 to adjust the solids concentration of the resin solution to 36% by weight, thus preparing a hard coating forming material. The prepared forming material was then coated onto a transparent protective film containing triacetyl cellulose (KONICA MINOLTA TAC film, trade name "KC4UY", thickness: 40 μm) to form a coating film. The coating thickness was adjusted to achieve a hard coating thickness of 7 μm obtained by curing the forming material. Next, the coating was dried at 90°C for 1 minute and then further irradiated with a high-pressure mercury lamp with a cumulative light intensity of 300 mJ / cm². 2 The ultraviolet light was then applied. The coating cured, resulting in a protective film A (47 μm thick) with a hard coating layer (HC).

[0290] (Making polarizer A)

[0291] A polyvinyl alcohol (PVA) film with an average degree of polymerization of 2400, a saponification degree of 99.9 mol%, and a thickness of 45 μm was immersed in a swelling bath (water bath) at 20°C for 30 seconds to swell, and then stretched to 2.2 times its original length along the transport direction (swelling process). Next, in a dyeing bath at 30°C (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a 1:7 weight ratio relative to 100 parts by weight of water), the concentration was adjusted to achieve an iodine concentration of 3.1 wt% for the final polarizer, and the film was immersed for 30 seconds for dyeing. Simultaneously, the film was stretched to 3.3 times its original length along the transport direction (dyeing process) based on the original PVA film (a completely unstretched PVA film along the transport direction). Rollers with different circumferential speeds were used for stretching. Next, the dyed PVA film was immersed in a crosslinking bath at 40°C (an aqueous solution of 3.5 wt% boric acid, 3.0 wt% potassium iodide, and 3.6 wt% zinc sulfate) for 28 seconds, and stretched to 3.6 times its original thickness along the transport direction (crosslinking process). Then, the crosslinked PVA film was immersed in a stretching bath at 64°C (an aqueous solution of 4.5 wt% boric acid, 5.0 wt% potassium iodide, and 5.0 wt% zinc sulfate) for 60 seconds, and stretched to 6.0 times its original thickness along the transport direction (stretching process). Next, it was immersed in a cleaning bath at 27°C (an aqueous solution of 2.3 wt% potassium iodide) for 10 seconds (cleaning process), and the cleaned PVA film was dried at 40°C for 30 seconds to obtain a polarizer A with a thickness of 18 μm.

[0292] (Making polarizer B)

[0293] Using rollers with different circumferential speeds, an 80 μm thick PVA film was dyed in an iodine aqueous solution (0.3 wt%) at 30°C for 1 minute and stretched to 3.0 times its original thickness along the transport direction. Next, it was immersed in an aqueous solution of 4 wt% boric acid and 10 wt% potassium iodide at 60°C for 0.5 minutes and stretched to 6.0 times its original thickness along the transport direction. After rinsing in an aqueous solution of 1.5 wt% potassium iodide at 30°C for 10 seconds, it was dried at 50°C for 4 minutes to obtain a 28 μm thick polarizer B.

[0294] (Making of polarizer C)

[0295] Using rollers with different circumferential speeds, a 60 μm thick PVA film was dyed in an iodine aqueous solution (0.3 wt%) at 30 °C for 1 minute and stretched to 3.0 times its original thickness along the transport direction. Next, it was immersed in an aqueous solution of 4 wt% boric acid and 10 wt% potassium iodide at 60 °C for 0.5 minutes and stretched to 6.0 times its original thickness along the transport direction. After rinsing in an aqueous solution of 1.5 wt% potassium iodide at 30 °C for 10 seconds, it was dried at 50 °C for 4 minutes to obtain a 22 μm thick polarizer C.

[0296] (Fabrication of phase retardation film A)

[0297] In a high-pressure autoclave equipped with a stirrer, cooling pipe, nitrogen inlet pipe, and thermometer, 48 parts by weight of hydroxypropyl methylcellulose (Shin-Etsu Chemical, Metalose 60SH-50), 1560 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate, 240 parts by weight of 3-ethyl-3-oxetanebutyl methyl acrylate, and 45 parts by weight of tert-butyl peroxypentanoate as a polymerization initiator were placed. After bubbling with nitrogen for 1 hour, the mixture was stirred and kept at 49°C for 24 hours for free radical suspension polymerization. The mixture was then cooled to room temperature, and the resulting fumarate resin particles were centrifuged. The particles were washed twice with distilled water and twice with methanol, and then dried under reduced pressure. The particles were then dissolved in a toluene / methyl ethyl ketone mixture (50% by weight / 50% by weight) to prepare a 20% by weight solution. Furthermore, a coating solution (dope) was prepared by adding 5 parts by weight of tributyl trimellitate as a plasticizer, relative to 100 parts by weight of fumarate resin. The prepared coating solution was then coated onto a support film to achieve a dried film thickness of 6.3 μm, and dried at 140°C. The support was a biaxially stretched polyester (polyethylene terephthalate / polyethylene isophthalate copolymer) film (75 μm thick, heat-treated). The resulting laminate was then uniaxially stretched at 140°C. The support film was peeled off from the stretched laminate to obtain a phase retardation film A (6 μm thick, Re(550) of 35 nm).

[0298] (Fabrication of polarizing film A)

[0299] Using a roller laminator, a protective film A with HC was laminated to one main surface of a polarizer A, and a phase retardation film B (a 17 μm thick cyclic olefin film, ZT12, manufactured by Zeon, Japan) was laminated to the other main surface. The lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing acetylacetyl PVA (average degree of polymerization 1200, degree of saponification 98.5 mol%, degree of acetylacetylation 5 mol%) and hydroxymethyl melamine in a 3:1 weight ratio. After drying the entire assembly in an oven, a photocurable adhesive composition was applied to the phase retardation film B side of the resulting laminated film to a thickness of 1 μm. The coating was performed using an MCD coating machine (manufactured by Fuji Machinery). The composition of the adhesive composition is described below.

[0300] • 20 parts by weight of ε-cyclohexanolide modified with unsaturated fatty acid hydroxyalkyl esters (Daicel preparation, Placcel FA1DDM)

[0301] Acryloylmorpholine (Xingren Manufacturing) 20 parts by weight

[0302] · Diethylacrylamide (manufactured by KJ Chemicals, DEAA) 3 parts by weight

[0303] • 6.7 parts by weight of lauryl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., "Light Acrylate LA").

[0304] • Isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., ISTA) 27 parts by weight

[0305] · 1,9-Nonadiol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Light Acrylate 1,9ND-A) 10 parts by weight

[0306] • 13.3 parts by weight of butyl acrylate and methacrylate 34 / 66 molar ratio copolymer oligomer (Toa Synthetic, ARUFONUP-1190, molecular weight 1700)

[0307] • As a photoinitiator, 3 parts by weight of Omnirad 907 (manufactured by IGM Resins BV)

[0308] • As a photoinitiator, 3 parts by weight of diethylthioxanone (manufactured by Nippon Kayaku Co., Ltd., KAYACURE DETX-S)

[0309] Next, the retardation film A prepared above is bonded to the coated adhesive composition using a roller laminator. The bonding is performed at 30°C. Then, visible light is irradiated from one side of the retardation film A using a gallium-encapsulated metal halide lamp as the light source (irradiation device: Fusion UV Systems, Inc. Light HAMMER10, lamp type: V-type, peak illuminance: 1600 mW / cm²). 2 The cumulative irradiation dose at wavelengths of 380~440nm is 1000 / mJ / cm. 2 The adhesive composition was cured using active energy rays. Then, it was heat-dried at 70°C for 3 minutes to obtain polarizing film A. The polarizing film A obtained by the above method has a curl diameter of 6.0 mm and a bending moment M of 3.0 × 10⁻⁶ mm. 6 .

[0310] (Fabrication of polarizing film B)

[0311] Using a roller laminator, a protective film A containing HC was laminated to one main surface of a polarizer A, and a transparent protective film (manufactured by Nippon Shokubai, 30 μm thick) made of a modified acrylic polymer with an lactone ring structure was laminated to the other main surface. The lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing 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. The entire assembly was then dried in an oven to obtain polarizing film B. The polarizing film B obtained by the above method had a curl diameter of 6.0 mm and a bending moment M of 2.0 × 10⁻⁶ mm. 6 .

[0312] (Fabrication of polarizing film C)

[0313] A transparent protective film containing triacetyl cellulose (Fujifilm TAC film, trade name "TG40UL", thickness 40 μm), was laminated onto one main surface of polarizer A using a roller laminator. A transparent protective film (Nippon Shokubai, thickness 30 μm), formed from a modified acrylic polymer with an lactone ring structure, was laminated onto the other main surface. The lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing 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. The entire assembly was then dried in an oven to obtain polarizing film C. The polarizing film C obtained by the above method had a curl diameter of 3.0 mm and a bending moment M of 3.5 × 10⁻⁶ mm. 6 .

[0314] (Fabrication of polarizing film D)

[0315] Using a roller laminator, a protective film A containing HC was laminated onto one main surface of a polarizer B, while a transparent protective film (manufactured by Nippon Shokubai, 30 μm thick) made of a modified acrylic polymer with an lactone ring structure was laminated onto the other main surface. The lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing 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. The entire assembly was then dried in an oven to obtain polarizing film D. The polarizing film D obtained by the above method had a curl diameter of 7.8 mm and a bending moment M of 3.0 × 10⁻⁶ mm. 6 .

[0316] (Fabrication of polarizing film E)

[0317] A transparent protective film containing triacetyl cellulose (Fujifilm TAC film, trade name "TG40UL", thickness 40 μm), was laminated onto one main surface of polarizer C using a roller laminator. A transparent protective film (Nippon Shokubai, thickness 20 μm), formed from a modified acrylic polymer with an lactone ring structure, was laminated onto the other main surface. The lamination was performed at 30°C using an adhesive. The adhesive used was an aqueous solution containing 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. The entire assembly was then dried in an oven to obtain polarizing film E. The polarizing film E obtained by the above method had a curl diameter of 2.5 mm and a bending moment M of 8.0 × 10⁻⁶ mm. 6 .

[0318] <Creation of the first layer L1>

[0319] For the exposed surface of the transparent protective film in each of the polarizing films prepared above, any of the coating solutions prepared above are applied, and the resulting coated film is dried at a given temperature for 1 minute, thereby producing the first laminates L1-1 to L1-21 with an antistatic layer / polarizing film laminate structure. Table 2 below shows the manufacturing conditions and thickness of the antistatic layer of each of the first laminates L1.

[0320]

[0321] [Evaluation of the surface resistivity of the antistatic layer]

[0322] For each first-layer laminate L1 fabricated, the surface resistivity of the antistatic layer was evaluated before and after the DIN test. The DIN test was conducted according to the weathering test (test conditions: Z-IN1) specified in DIN 75220. For surface resistivity, the test was conducted at various time points before and after the DIN test using a Hiresta MCP-HT800 (manufactured by Mitsubishi Chemical Analytech) according to the method specified in JIS K6911:1995, with an applied voltage of 10V and an application time of 10 seconds. The surface resistivity was evaluated at 25°C. The evaluation results are shown in Table 3 below.

[0323]

[0324] [Fabrication of the second laminate L2 formed by the substrate and adhesive sheet]

[0325] Preparation of (meth)acrylic acid polymers

[0326] 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 to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet, and cooler. Next, 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 to each 100 parts by weight of the monomer mixture. The mixture was stirred slowly, and nitrogen was introduced into the flask for nitrogen purging. The liquid temperature in the flask was maintained at approximately 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of a (meth)acrylic acid polymer with a weight-average molecular weight (Mw) of 2 million.

[0327] The weight-average molecular weight (Mw) of (meth)acrylic acid polymers was determined by GPC (gel permeation chromatography). The determination conditions for GPC are shown below.

[0328] ·Analysis device: Made by Tosoh Corporation, HLC-8120GPC

[0329] ·Pillar: Made by Tosoh Corporation, G7000HXL+GMHXL+GMHXL

[0330] • Column dimensions: 7.8mm Φ x 30cm each, total 90cm

[0331] Column temperature: 40℃

[0332] • Flow rate: 0.8 mL / min

[0333] Injection volume: 100μL

[0334] • Eluent: Tetrahydrofuran

[0335] • Detector: Differential refractive index detector (RI)

[0336] Standard sample: polystyrene

[0337] <Fabrication of the adhesive sheet and the second laminate L2>

[0338] In addition to 100 parts by weight of the solid component of the (meth)acrylic acid polymer solution prepared above, 0.3 parts by weight of a crosslinking agent (manufactured by Tosoh Corporation, trade name: Coronate 2770) and 8 parts by weight of 1-ethyl-3-methylimidazolium as an antistatic agent are further added. A solution of a (meth)acrylic adhesive composition was prepared using bis(fluorosulfonyl)imide (EMI-FSI) (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., trade name: Elexcel AS110) and 0.5 parts by weight of an antioxidant (manufactured by BASF, trade name: Irganox 1010). The prepared solution was then coated onto one side of a release film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38). The release film used was a polyethylene terephthalate film surface-treated with a silicone-based release agent. The coated film was dried at 155°C for 1 minute, thereby obtaining a second laminate L2-1 with an adhesive sheet formed on the surface of the release film. The thickness of the formed adhesive sheet was 20 μm. Furthermore, by setting the amount of an antistatic agent to 6 parts by weight, a second laminate L2-2 with an adhesive sheet formed on the surface of the release film was obtained in the same manner as described above. For each fabricated second laminate L2, the surface resistivity of the adhesive sheet was evaluated, and the result for laminate L2-1 was 2.0 × 10⁻⁶. 8 Ω / □, the laminate L2-2 is 2.0×10 9 Ω / □. The surface resistivity of the adhesive sheet was measured in the same manner as that of the antistatic layer (applied voltage 10V, applied time 10 seconds, ambient temperature 25°C). The surface resistivity of the adhesive sheet remained essentially unchanged before and after the DIN test.

[0339] [Fabrication of Optical Laminates]

[0340] The adhesive sheets of each of the second laminates L2 fabricated above were bonded to the antistatic layer of each of the first laminates L1 to obtain an optical laminate in which a polarizing film, an antistatic layer, an adhesive sheet, and a release film are sequentially stacked. Optical laminates fabricated using the first laminates L1-1 to L1-15 and L1-19 to L1-21 were designated as Examples 1 to 15 and Examples 16 to 18, respectively. Optical laminates fabricated using the first laminates L1-16 to L1-18 were designated as Comparative Examples 1 to 3, respectively. For each optical laminate of Examples 1 to 18 and Comparative Examples 1 to 3, the following evaluations were performed before and after the DIN test. Furthermore, for each fabricated optical laminate (before the DIN test), curling and the loss of total light transmittance caused by the antistatic layer were evaluated. The loss of total light transmittance was assessed using the method described above.

[0341] (curly)

[0342] The degree of curling in the fabricated optical laminates was evaluated by visual inspection. The evaluation criteria are as follows.

[0343] A: Curl is suppressed, which is good.

[0344] B: Slightly curled, but no problem with use.

[0345] C: Curl can be observed, but there are no problems with its use.

[0346] D: Severe curling may cause problems during use.

[0347] (ESD test)

[0348] After the release film is peeled from the optical laminate of the evaluation object, it is then bonded to the optical laminate via an adhesive sheet. Figure 7 The visible side of the embedded image display panel (liquid crystal panel) is shown. Next, a 10mm wide strip of silver paste is applied to the side portion of the polarizing film and connected to an external ground electrode. The silver paste is applied to cover the side portion of the polarizing film, the antistatic layer, and the adhesive sheet. Next, the image display panel is placed on a backlight device, and an electrostatic discharge gun is used to apply a voltage of 9kV to the polarizing film surface on the visible side to check for any abnormalities in the display function. The evaluation criteria are as follows.

[0349] A: No abnormalities were observed in the screen, and the display function is normal.

[0350] B: The screen displays abnormalities such as horizontal lines or flickering, but the display function recovers automatically.

[0351] C: The screen displays abnormalities such as horizontal lines or flickering, and the display function has not been restored.

[0352] (TSP test)

[0353] After the release film is peeled from the optical laminate of the evaluation object, it is then bonded to the optical laminate via an adhesive sheet. Figure 7 The image shows the viewable side of an embedded image display panel (liquid crystal panel). Next, the lead-out wiring of the image display device, which is bonded to the optical laminate, located around the transparent electrode pattern, is connected to a controller IC to create an image display device with built-in touch sensing functionality. The input display of this touch sensor-based device is visually observed to confirm the absence of malfunctions.

[0354] A: No error.

[0355] D: Incorrect action

[0356] (Surface resistivity C, D)

[0357] The surface resistivity C (before DIN test) and surface resistivity D (after DIN test) of the main surface 5 of the adhesive sheet 1 in the optical laminate were measured using the above method. Using a Hiresta MCP-HT800 (manufactured by Mitsubishi Chemical Analytech) and a J-type U-shaped probe (MCP-JB03), the surface resistivity C and D were measured under the conditions of an applied voltage of 500V, an application time of 30 seconds, and an ambient temperature of 25°C, according to the method specified in JIS K6911:1995.

[0358] The evaluation results are shown in Table 4 below.

[0359]

[0360] As shown in Table 4, in each optical laminate of the embodiments, compared with each optical laminate of the comparative examples, the electrical characteristics after the DIN test environment are more suitable for use as an image display device. For 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 absolute value of logB-logA is greater than 1. Furthermore, in Example 1 where the drying temperature during the formation of the antistatic layer is 70°C, and in Examples 6 and 7 where the solvent of 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.

[0361] As shown in Table 4, when the drying temperature during the formation of the antistatic layer reaches 130°C or higher (Examples 4-5), the degree of curling will be stronger if a polarizing film with a smaller curling diameter is used.

[0362] Industrial applicability

[0363] The optical laminate of the present invention is suitable for use in image display devices in environments such as the interior of vehicles, where static electricity is easily generated due to the presence of other electronic devices in the surrounding environment, and where high temperature and humidity are easily reached.

Claims

1. An optical laminate comprising: an adhesive sheet, an antistatic layer, and an optical film. The antistatic layer satisfies the following equation (1), -2≤logB-logA≤2 (1) in, In the formula (1), A and B are the surface resistivity (unit: Ω / □) of the antistatic layer before and after the weathering test (test conditions: Z-IN1) specified by German industrial standard DIN75220.

2. The optical laminate according to claim 1, wherein, The surface resistivity B of the antistatic layer is 1.0 × 10⁻⁶. 6 Ω / □ or higher and 3.0 × 10 8 Below Ω / □.

3. The optical laminate according to claim 1, wherein, The thickness of the antistatic layer is greater than 5nm and less than 100nm.

4. The optical laminate according to claim 1, wherein, The antistatic layer contains carbon nanotubes.

5. The optical laminate according to claim 4, wherein, The carbon nanotubes have a length of 3 μm or more and 300 μm or less, and a diameter of 10 nm or less.

6. The optical laminate according to claim 1, wherein, The antistatic layer contains an adhesive resin.

7. The optical laminate according to claim 1, wherein, The antistatic layer contains an adhesive resin with a glass transition temperature of 0°C or higher.

8. The optical laminate according to claim 1, wherein, The antistatic layer does not actually contain leveling agents.

9. The optical laminate according to claim 1, wherein, The adhesive sheet is formed from an adhesive composition comprising a polymer (A).

10. The optical laminate according to claim 9, wherein, The polymer (A) is a (meth)acrylic acid polymer.

11. The optical laminate according to claim 9, wherein, The adhesive composition comprises the polymer (A) having a polyether structure as the main component.

12. The optical laminate according to claim 11, wherein, The polymer (A) has structural units derived from the monomers shown in the following formula (2). R in equation (2) 1 R is a hydrogen atom or a methyl group. 2 The alkyl group is an alkyl group, which may be a straight-chain alkyl group or a branched alkyl group, and n is an integer from 1 to 15.

13. The optical laminate according to claim 9, wherein, The adhesive composition further comprises an antistatic agent.

14. The optical laminate according to claim 13, wherein, In the adhesive composition, the amount of the antistatic agent is less than 30 parts by weight relative to 100 parts by weight of the polymer (A).

15. The optical laminate according to claim 1, wherein, The loss of total light transmittance caused by the antistatic layer is less than 1.0%.

16. The optical laminate according to claim 1, wherein, The optical film includes a polarizing film.

17. The optical laminate according to claim 16, wherein, The polarizing film, evaluated by the following test method, has a curl diameter of 3 mm or more. <Experimental Method> Prepare a rectangular test piece with a width of 10 mm and a length of 50 mm by processing the polarizing film with the absorption axis of the polarizer as the length direction. Then, fix one end of the test piece along the length direction to the surface of the evaluation piece. Next, heat the whole piece at 105°C for 12 hours. Starting from the other end along the length direction of the test piece, curl the test piece. Calculate the diameter of the cylindrical portion of the test piece formed by curling as the curling diameter.

18. The optical laminate according to claim 16, wherein, The absolute value of the bending moment M of the polarizing film during heating is less than 1×10. 9 .

19. The optical laminate according to claim 1, wherein, The antistatic layer comprises carbon nanotubes and an adhesive resin with a glass transition temperature above 0°C.

20. The optical laminate according to claim 19, wherein, The carbon nanotubes have a length of 3 μm or more and 300 μm or less, and a diameter of 10 nm or less.

21. The optical laminate according to claim 1, comprising, in sequence, the adhesive sheet, the antistatic layer, and the optical film. The optical laminate satisfies the following equation (4), -1≤logD-logC≤2 (4) in, In equation (4), C represents the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that is opposite to the antistatic layer. In Equation (4), D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that has undergone the weathering test, which is opposite to the antistatic layer.

22. An optical laminate, comprising sequentially an adhesive sheet, an antistatic layer, and an optical film, The optical laminate satisfies the following equation (4), -1≤logD-logC≤2 (4) in, In equation (4), C represents the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that is opposite to the antistatic layer. In the formula (4), D is the surface resistivity (unit: Ω / □) of the main surface of the adhesive sheet in the optical laminate that is opposite to the antistatic layer, after passing the weather resistance test specified in German industrial standard DIN75220 (test conditions: Z-IN1).

23. An image display panel comprising the optical laminate according to any one of claims 1 to 22.

24. An image display device comprising the image display panel of claim 23.

Images