Optical laminate

Abstract

Provided is an optical laminate, in which the ends of a polarizer are prevented from becoming built up. An optical laminate 1 comprises, in the following order: an optical film 109 including an adhesive layer; a polarizer 101 in which a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film; a first bonding layer 30a; a retardation plate 20; and a second bonding layer 30b. In the optical laminate 1, the optical film 109 including the adhesive layer and the polarizer 101 are in direct contact with each other. In the optical laminate 1, the polarizer 101 and the first bonding layer 30a are in direct contact with each other. A layer composed of the first bonding layer 30a, the retardation plate 20 and the second bonding layer 30b has an absorbance of 0.1 or more with respect to light having a wavelength of 340 nm.

Description

optical laminate

[0001] The present invention relates to an optical laminate.

[0002] An optical laminate including a polarizer made of a polyvinyl alcohol-based resin film is known. Patent Document 1 discloses an optical laminate including a structure for protecting the polarizer. Specifically, the optical laminate disclosed in Patent Document 1 includes a polarizer protective film for protecting the polarizer laminated on the polarizer.

[0003] Japanese Patent Application Laid-Open No. 2022-101448

[0004] The present inventors have found that an optical laminate having the above-described structure for protecting a polarizer causes a phenomenon in which the edge of the polarizer bulges in a high-temperature environment. There is a demand for an optical laminate that can suppress the occurrence of this phenomenon.

[0005] The present invention includes the following inventions: [Invention 1] An optical laminate comprising, in this order, an optical film including a pressure-sensitive adhesive layer, a polarizer in which a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film, a first attaching layer, a retardation plate, and a second attaching layer, wherein the pressure-sensitive adhesive layer side of the optical film is in direct contact with the polarizer, the polarizer is in direct contact with the first attaching layer, and a layer formed by the first attaching layer, the retardation plate, and the second attaching layer has an absorbance of 0.1 or more for light with a wavelength of 340 nm.

[0006] [Invention 2] The optical laminate according to [Invention 1], wherein the polarizer has a boron content of 0.5 mass % or more.

[0007] [Invention 3] The optical laminate according to [Invention 1] or [Invention 2], wherein the polarizer has a luminosity-corrected single transmittance of 41% or more, and a luminosity-corrected polarization degree of 99.5% or more.

[0008] [Invention 4] The optical laminate according to any one of [Invention 1] to [Invention 3], wherein the retardation plate is made of a liquid crystal cured layer.

[0009] [Invention 5] The optical laminate according to any one of [Invention 1] to [Invention 4], wherein the retardation plate is a λ / 4 retardation plate exhibiting reverse wavelength dispersion.

[0010] [Invention 6] The optical laminate according to any one of [Invention 1] to [Invention 5], wherein the first attaching layer is a pressure-sensitive adhesive layer.

[0011] [Invention 7] The optical laminate according to any one of [Invention 1] to [Invention 6], wherein the first attaching layer contains an ultraviolet absorber.

[0012] According to the optical laminate of the present invention, it is possible to prevent the edges of the polarizer from swelling up.

[0013] Fig. 1 is a cross-sectional view showing the layer structure of one embodiment of an optical laminate. Fig. 2 is a cross-sectional view showing the layer structure of another example of an optical laminate. Fig. 3 is an explanatory diagram illustrating microscopic Raman spectroscopy analysis of a polarizing plate according to this embodiment. Fig. 4 is a schematic diagram illustrating an evaluation sample for an edge swelling test. Fig. 5 is a graph showing an example of measurement results in the edge swelling test.

[0014] An embodiment of the optical laminate will be described below. Fig. 1 is a schematic cross-sectional view illustrating the layer configuration of an optical laminate 1 of this embodiment. Fig. 2 shows an optical laminate 2 including an image display element 40.

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. (1) Optical Laminate As shown in FIG. 1, the optical laminate 1 includes an optical film 109 including a pressure-sensitive adhesive layer, a polarizer 101, a first bonding layer 30a, a retardation plate 20, and a second bonding layer 30b, in this order. In FIG. 1, the optical film including a pressure-sensitive adhesive layer includes a surface protection film for protecting the surface of the polarizer 101. For example, the surface protection film is an optical film in which a pressure-sensitive adhesive layer is formed on the surface of a resin film for surface protection film. The optical film on which a pressure-sensitive adhesive layer is formed corresponds to the optical film including a pressure-sensitive adhesive layer. The surface protection film may be a self-adhesive optical film. In this case, the self-adhesive optical film corresponds to the optical film including a pressure-sensitive adhesive layer.

[0016] For example, the surface protection film is configured so that the entire pressure-sensitive adhesive layer can be peeled off from the polarizer 101. In this case, the optical laminate 1 is used in a state where the surface protection film is removed together with the pressure-sensitive adhesive layer.

[0017] For example, the surface protection film is configured so that the resin film for the surface protection film can be peeled off while the pressure-sensitive adhesive layer remains attached to the polarizer 101. In this case, the optical laminate 1 is used in a state in which the resin film for the surface protection film is removed and the pressure-sensitive adhesive layer is laminated on the polarizer 101. The pressure-sensitive adhesive layer laminated on the polarizer 101 after the resin film for the surface protection film is removed is used to bond the optical laminate 1 to a component disposed on the opposite side of the polarizer 101 from the retardation film 20. Therefore, the pressure-sensitive adhesive layer is different from a protective layer that may be laminated on a polarizer for the purpose of protecting the polarizer. Note that an example of the component disposed on the opposite side of the polarizer 101 from the retardation film 20 is a front panel.

[0018] In the optical laminate 1, the optical film 109 including a pressure-sensitive adhesive layer and the polarizer 101 are in direct contact with each other via the pressure-sensitive adhesive layer. Furthermore, in the optical laminate 1, the first bonding layer 30a is in direct contact with the surface of the polarizer 101 opposite to the surface that is in direct contact with the optical film 109 via the pressure-sensitive adhesive layer. That is, the optical laminate 1 does not include a protective film (hereinafter sometimes referred to as a "polarizer protective film") or protective layer that protects the polarizer 101. The polarizer protective film is used in the optical laminate in a state where it is laminated on the polarizer, and is different from the optical film 109 including a pressure-sensitive adhesive layer that is peeled off during use. Like the polarizer protective film, the protective layer is also used in the optical laminate in a state where it is laminated on the polarizer. As described above, the protective layer is different from the pressure-sensitive adhesive layer that remains laminated on the polarizer 101 after the resin film for the surface protective film is removed from the surface protective film. Thus, the polarizer protective film and the protective layer are different from the optical film 109 including a pressure-sensitive adhesive layer that is peeled off during use.

[0019] Here, a polarizer protective film that is not provided in the optical laminate 1 will be described. A thermoplastic resin film is used as the polarizer protective film. The polarizer protective film is laminated to the polarizer, for example, by the self-adhesive properties of the protective film. The polarizer protective film is laminated, for example, via an adhesive layer or a pressure-sensitive adhesive layer.

[0020] The protective layer not included in the optical laminate 1 will now be described. A polymer with a high crosslinking density is used as the protective layer. Another example of the protective layer is a water-soluble polymer with high hydrophilic interaction. The protective layer is laminated on the polarizer without an adhesive layer or pressure-sensitive adhesive layer.

[0021] The optical laminate 1 may include one or more other layers between the first bonding layer 30 a, the retardation film 20, and the second bonding layer 30 b. The other layers that the optical laminate 1 may include are excluding the polarizer protective film and the protective layer.

[0022] The retardation plate 20 includes, for example, a first liquid crystal cured layer 201, a third bonding layer 30c, and a second liquid crystal cured layer 202, in this order from the polarizer 101 side. For example, the retardation plate 20 is preferably a λ / 4 retardation plate exhibiting reverse wavelength dispersion, which will be described later.

[0023] As shown in Fig. 2, the optical laminate 2 includes a polarizer 101, a first bonding layer 30a, a retardation film 20, and a second bonding layer 30b on the viewing side of the image display element 40. The polarizer 101, the first bonding layer 30a, the retardation film 20, the second bonding layer 30b, and the image display element 40 are arranged in this order. The layers laminated on the viewing side of the image display element 40 can be the same as those in the optical laminate 1. The optical laminate 2 including the image display element 40 may further include an optical film 109 including a pressure-sensitive adhesive layer in direct contact with the polarizer 101, as in the optical laminate 1 shown in Fig. 1.

[0024] In the optical laminate 1, the thickness from the surface of the polarizer 101 on the optical film 109 side including the pressure-sensitive adhesive layer to the surface of the second bonding layer 30b opposite the retardation plate 20 is, for example, 20 μm or more and 50 μm or less. The upper limit of the above range is preferably 48 μm, more preferably 40 μm. The lower limit of the above range is preferably 25 μm, more preferably 28 μm. According to this embodiment, the thickness of the optical laminate can be reduced by not providing a protective film or protective layer that protects the polarizer 101. According to this embodiment, by employing an optically anisotropic layer described below as a layer that exhibits retardation, the thickness of the optical laminate can be reduced compared to when a retardation film is employed.

[0025] The phenomenon of the polarizer edge swelling in a high-temperature environment is thought to be caused by the difference between the shrinkage rate of the polarizer and the shrinkage rate of the protective film. Specifically, the edge swelling is thought to occur because the shrinkage rate of the polarizer is greater than that of the protective film. For example, when a protective film is disposed on the surface of the polarizer opposite the viewing side of the optical laminate, warping toward the polarizer side is likely to occur, and the edge swelling is likely to occur.

[0026] In this regard, the optical laminate of this embodiment does not include a protective film or protective layer for protecting the polarizer 101 (hereinafter, sometimes referred to as a "bare film"), and therefore can suppress the bulging of the end of the polarizer 101. In more detail, the optical laminate 1 of this embodiment has the polarizer 101, the first bonding layer 30a, and the retardation plate 20 laminated in this order. Furthermore, in the optical laminate 1 of this embodiment, the polarizer 101 and the first bonding layer 30a are in direct contact with each other. Therefore, the first bonding layer 30a can easily follow the contraction of the polarizer 101. This can suppress the bulging of the end of the polarizer 101.

[0027] Furthermore, the present inventors have confirmed that in an optical laminate bonded to an image display element, the longer the distance from the image display element to the polarizer, the more likely the edge swelling is to occur. In this regard, in the optical laminate of this embodiment, the thickness of the optical laminate can be reduced as described above, thereby shortening the distance from the image display element to the polarizer. This further suppresses the edge swelling.

[0028] In the optical laminate 1, the layer constituted by the first bonding layer 30a, the retardation film 20, and the second bonding layer 30b has an absorbance of, for example, 0.1 or more and 5 or less for light with a wavelength of 340 nm. The upper limit of the absorbance is preferably 4.5, more preferably 3.5, even more preferably 3.0, and particularly preferably 2.5. The lower limit of the absorbance is preferably 0.5, more preferably 1.0, and even more preferably 2.0.

[0029] If the optical laminate 1 has other layers between the first bonding layer 30a, the retardation film 20, and the second bonding layer 30b, it is preferable that the absorbance measured including those layers is within the above range.

[0030] Known optical laminates include those in which a protective film or protective layer that protects the polarizer contains an ultraviolet absorber, a light stabilizer, and the like. That is, the protective film or protective layer is used to impart weather resistance to the optical laminate. In contrast, the optical laminate of this embodiment does not include a protective film or protective layer that protects the polarizer 101, but the layer composed of the first bonding layer 30a, the retardation plate 20, and the second bonding layer 30b has an absorbance of 0.1 or more for light with a wavelength of 340 nm. This makes it difficult for the luminosity-corrected polarization degree Py in the optical laminate to decrease over time, so the optical laminate of this embodiment has excellent weather resistance despite being a bare film.

[0031] If the absorbance is 0.1 or less, deterioration due to ultraviolet light reflected by the image display element is likely to occur. In this regard, the optical laminate of this embodiment can suppress deterioration due to ultraviolet light even though it is a bare film. Therefore, it is possible to suppress a decrease in the luminous efficacy-corrected polarization index Py that may occur due to deterioration due to ultraviolet light.

[0032] In the optical laminate of this embodiment, which does not include a protective film or protective layer for protecting the polarizer 101, if the absorbance is 5 or more, thermal degradation becomes significant in a weather resistance test. In this regard, the optical laminate of this embodiment can suppress thermal degradation even though it is a bare film. Therefore, an increase in luminous efficiency-corrected single transmittance Ty and a decrease in luminous efficiency-corrected polarization degree Py that may occur due to thermal degradation can be suppressed.

[0033] It is preferable that at least one of the first bonding layer 30a, the retardation film 20, and the second bonding layer 30b has ultraviolet absorbing properties in the optical laminate 1. In particular, it is particularly preferable that the first bonding layer 30a has ultraviolet absorbing properties.

[0034] When at least one of the first bonding layer 30a, the retardation film 20, and the second bonding layer 30b has ultraviolet absorption properties, a decrease in the luminosity-corrected polarization degree Py in the optical laminate is easily suppressed.

[0035] In particular, when the first bonding layer 30a contains ultraviolet absorbing properties, ultraviolet rays can be absorbed by the layer disposed between the polarizer 101 and the retardation film 20, thereby suppressing deterioration of the retardation film 20.

[0036] The elements that constitute or can constitute the optical laminate 1 will be described in detail below. (2) Polarizer The polarizer 101 is an optical film (linear polarizer) that has the property of transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis when unpolarized light is incident. Specifically, the polarizer 101 is a polyvinyl alcohol-based resin film (hereinafter also referred to as a "PVA-based film") on which a dichroic dye is adsorbed and oriented.

[0037] The polyvinyl alcohol resin (hereinafter also referred to as "PVA resin") constituting the PVA film can be produced by saponifying a polyvinyl acetate resin. The polyvinyl acetate resin can be a copolymer of vinyl acetate and another monomer copolymerizable with vinyl acetate, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group. In this specification, "(meth)acrylic" refers to either acrylic or methacrylic. The "(meth)" in (meth)acrylate, etc., has the same meaning.

[0038] The saponification degree of the PVA-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The PVA-based resin may be modified; for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may also be used. The average polymerization degree of the PVA-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The average polymerization degree of the PVA-based resin can be determined in accordance with JIS K 6726 (1994). If the average polymerization degree is less than 1,000, it is difficult to obtain favorable polarizing performance, and if it exceeds 10,000, film processability may be poor.

[0039] The polarizer 101 is usually produced through a process of uniaxially stretching a PVA-based film, a process of dyeing the PVA-based film with a dichroic dye to adsorb the dichroic dye, a process of treating the PVA-based film with the adsorbed dichroic dye with a boric acid aqueous solution to crosslink the film, and a process of washing the film with water after the crosslinking treatment with the boric acid aqueous solution (hereinafter also referred to as boric acid treatment).

[0040] Uniaxial stretching of a PVA-based film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing, it may be performed before or during the boric acid treatment. Of course, uniaxial stretching can also be performed in multiple stages as shown here. Examples of uniaxial stretching include uniaxial stretching in the film transport direction between rolls with different peripheral speeds, uniaxial stretching in the film transport direction using a heated roll, and stretching in the width direction using a tenter. Uniaxial stretching may be performed by dry stretching in the air, or by wet stretching in which the PVA-based film is swollen using a solvent such as water. The stretching ratio is usually about 3 to 8 times.

[0041] Dyeing of a PVA-based film with a dichroic dye can be carried out, for example, by immersing the PVA-based film in an aqueous solution containing the dichroic dye. Specific examples of the dichroic dye include iodine and dichroic organic dyes. It is preferable to immerse the PVA-based film in water to swell it before dyeing.

[0042] When iodine is used as the dichroic dye, a method of dyeing a PVA-based film by immersing it in an aqueous solution containing iodine and potassium iodide is usually employed. The iodine content in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water, and the potassium iodide content is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. The immersion time in this aqueous solution (dyeing time) is usually about 20 to 1,800 seconds.

[0043] On the other hand, when a dichroic organic dye is used as the dichroic pigment, a method of dyeing a PVA-based film by immersing it in an aqueous solution containing a water-soluble dichroic organic dye is typically employed. The content of the dichroic organic dye in this aqueous solution is typically about 0.0001 to 10 parts by mass, and preferably 0.001 to 1 part by mass, per 100 parts by mass of water. This aqueous dye solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the aqueous dichroic organic dye solution used for dyeing is typically about 20 to 80°C. The immersion time in this aqueous solution (dyeing time) is typically about 10 to 1,800 seconds.

[0044] The boric acid treatment after dyeing with a dichroic dye can be carried out by immersing the dyed PVA-based film in a boric acid-containing aqueous solution. The content of boric acid in the boric acid-containing aqueous solution is typically about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is typically about 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is typically about 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is typically 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

[0045] The PVA-based film after the boric acid treatment is usually washed with water. The washing can be performed, for example, by immersing the boric acid-treated PVA-based film in water. The temperature of the water used in the washing is usually about 5 to 40°C. The immersion time is usually about 1 to 120 seconds.

[0046] After washing with water, the polarizer 101 is dried to obtain it. The drying can be performed using a hot air dryer or a far-infrared heater. The temperature for the drying is usually about 30 to 100°C, preferably 50 to 80°C. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. The drying reduces the moisture content in the polarizer 101 to a practical level. The moisture content is usually about 5 to 20% by mass, preferably 8 to 15% by mass, relative to the total mass of the polarizer 101. When the moisture content is 5% by mass or more, the polarizer 101 has sufficient flexibility, and therefore damage or breakage after drying can be suppressed. Furthermore, when the moisture content is 20% by mass or less, the polarizer 101 has sufficient thermal stability.

[0047] In this manner, the polarizer 101 can be produced in which the dichroic dye is adsorbed and aligned in the PVA-based film. The boron content of the polarizer 101 is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, even more preferably 2.5% by mass or more, and may be 3.5% by mass or more. When the boron content of the polarizer 101 is within the above range, polyvinyl alcohol molecular chains are likely to be crosslinked with boric acid, i.e., the polarizer 101 is likely to have a high degree of crosslinking. The high degree of crosslinking of the polarizer 101 can improve the weather resistance of the polarizer 101. This makes it easier to use the optical laminate 1 with the surface protection film as the optical film 109 including the pressure-sensitive adhesive layer removed. The boron content of the polarizer 101 is preferably 5.5% by mass or less, more preferably 5.0% by mass or less, and even more preferably 4.5% by mass or less. A boron content of 4.5% by mass or less can suppress shrinkage of the polarizer 101 caused by heating.

[0048] The "boric acid crosslinking index" of the polarizer 101 used in this embodiment is preferably high from the viewpoint of durability. The boric acid crosslinking index is preferably 0.5 or higher, more preferably 0.8 or higher, even more preferably 1.0 or higher, and even more preferably 1.2 or higher. In this specification, the "boric acid crosslinking index" refers to an index representing the degree to which polyvinyl alcohol molecular chains are crosslinked with boric acid in a polarizer made of a polyvinyl alcohol-based resin film or the like. The higher the boric acid crosslinking index, the more advanced the boric acid crosslinking between polyvinyl alcohol molecular chains in the polarizer. Having the boric acid crosslinking index of the polarizer 101 within this range allows iodine to be stably retained. As a result, it is easier to prevent a decrease in the polarization degree of the polarizer 101, and ultimately, the durability of the circular polarizing plate is improved. The boric acid crosslinking index can be adjusted by changing the manufacturing conditions of the polarizer, such as the content of boric acid in the boric acid-containing aqueous solution, the temperature of the boric acid-containing aqueous solution, and the temperature of the drying treatment.

[0049] The boric acid crosslinking index of the polarizer 101 can be determined by micro-Raman spectroscopy. In the micro-Raman spectroscopy, a laser Raman spectrophotometer (trade name: "NRS-5100", manufactured by JASCO Corporation) was used to measure the boric acid crosslinking index of the polarizer at a wave number of 780 cm. －１ Raman scattering intensity at wavenumber 850 cm －１ The Raman scattered light intensities at these wavenumbers were then calculated and divided by the Raman scattered light intensities at the wavenumber 780 cm －１ Raman scattering light intensity at wavenumber 850 cm －１ The boric acid crosslinking index can be calculated by measuring the Raman scattered light intensity at 1000 kJ / cm2.

[0050] 3 is an explanatory diagram illustrating microscopic Raman spectroscopy of the polarizing plate according to this embodiment. As shown in FIG. 3, in a laser Raman spectrophotometer, laser light is incident on the end face of the polarizer 101 so that the traveling direction of the laser light X and the absorption axis direction of the polarizer 101 are perpendicular to each other. Here, the laser light X is polarized in the thickness direction of the polarizer 101. The measurement position of the laser light is set to the center position in the thickness direction of the polarizer 101. It is preferable to process the cross section of the polarizing plate using a microtome before Raman spectroscopy. Wavenumber 780 cm －１ The Raman scattering light intensity at 850 cm / s is the Raman scattering light intensity attributable to the bond between polyvinyl alcohol and boron. －１ The Raman scattered light intensity in the above means the Raman scattered light intensity attributed to polyvinyl alcohol.

[0051] The various conditions used in the above-mentioned microscopic Raman spectroscopic analysis are as follows: Excitation wavelength: 532 nm Grating: 600 l / mm Slit width: 100 x 1000 μm Aperture: φ40 μm Objective lens: 100x Objective lens: 100x The luminosity-corrected polarization degree Py of the polarizer 101 is usually 95% or more, preferably 97% or more, more preferably 98% or more, even more preferably 98.7% or more, still more preferably 99.0% or more, particularly preferably 99.4% or more, and may even be 99.9% or more. Considering the optical laminate 1 in a state where the optical film 109 including the pressure-sensitive adhesive layer has been removed, it is preferably 99.5% or more, more preferably 99.91% or more. The luminosity-corrected polarization degree Py of the polarizer may be 99.99% or less. The luminosity-corrected degree of polarization Py can be calculated by using an integrating sphere spectrophotometer ("V7100" manufactured by JASCO Corporation) to perform luminosity correction on the obtained degree of polarization using a 2-degree field of view (C light source) according to "JIS Z 8701." Increasing the luminosity-corrected degree of polarization Py of the polarizer 101 is advantageous in improving the function of the circular polarizer as an anti-reflection film and the durability of the circular polarizer. If the luminosity-corrected degree of polarization Py of the polarizer 101 is less than 95%, it may not function as an anti-reflection film. The luminosity-corrected degree of polarization Py can be measured by the method described below.

[0052] Increasing the luminosity-corrected polarization degree Py of the polarizer is advantageous in terms of improving the function of the optical laminate as an antireflection film and the durability of the optical laminate. If the luminosity-corrected polarization degree Py of the polarizer is less than 95%, the polarizer may not function as an antireflection film.

[0053] The thickness of the polarizer is 15 μm or less, preferably 13 μm or less, and more preferably 10 μm or less. When the thickness of the polarizer is within this range, it is advantageous for thinning the optical laminate and can more effectively suppress the amount of change in retardation. The thickness of the polarizer is usually 2 μm or more, preferably 3 μm or more, and may be, for example, 5 μm or more.

[0054] The luminosity-corrected single transmittance Ty of the polarizer 101 is usually 40% or more, preferably 41% or more, and more preferably 42% or more. The luminosity-corrected single transmittance Ty of the polarizer 101 is usually 50% or less, and may be 48% or less, 46% or less, 44% or less, or 43% or less. If the luminosity-corrected single transmittance Ty is excessively high, the luminosity-corrected polarization degree Py may become too low, and the circular polarizer may not be able to function as an anti-reflection film. The luminosity-corrected single transmittance Ty can be measured by the method described below.

[0055] (3) Retardation Plate The retardation plate 20 includes a layer that exhibits retardation. The layer that exhibits retardation may be a retardation film formed by stretching a thermoplastic resin film or the like, or may be an optically anisotropic layer (hereinafter also referred to as a "retardation film") made of an oriented polymer of a polymerizable liquid crystal compound.

[0056] The thickness of the retardation plate 20 is, for example, 1 μm or more and 10 μm or less. The upper limit of the above range is preferably 8 μm, more preferably 6 μm. (3-1) Retardation Film It is preferable to coat a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as a "retardation film-forming composition") on a transparent substrate to form an optically anisotropic layer consisting of an oriented polymer of the polymerizable liquid crystal compound, in terms of enabling a thinner film and the ability to arbitrarily design wavelength dispersion characteristics. In addition, the retardation film-forming composition may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, an adhesion improver, and the like.

[0057] A retardation film is usually formed by applying a retardation film-forming composition onto an alignment film formed on a substrate and polymerizing the polymerizable liquid crystal compound contained in the retardation film-forming composition. The retardation film is usually a film in which the polymerizable liquid crystal compound is cured in an aligned state. In order to generate a retardation in the viewing plane, the retardation film needs to be a cured film in which the polymerizable group is polymerized in a state in which the polymerizable liquid crystal compound is aligned horizontally relative to the substrate surface. In this case, if the polymerizable liquid crystal compound is a rod-shaped liquid crystal, a positive A plate is sufficient, and if the polymerizable liquid crystal compound is a discotic liquid crystal, a negative A plate is sufficient.

[0058] The retardation film may include two or more different optically anisotropic layers. To achieve a high level of antireflection function, it is sufficient to have a λ / 4 plate function (i.e., a π / 2 retardation function) across the entire visible light range. Specifically, a reverse wavelength dispersion λ / 4 layer is preferred, or it is preferable to combine two or more retardation films with different orientations. For example, a retardation film having a λ / 2 plate function (i.e., a π retardation function) and a retardation film having a λ / 4 plate function (i.e., a π / 2 retardation function) may be combined. Furthermore, from the viewpoint of compensating for the antireflection function in oblique directions, it is preferable to further include a layer having anisotropy in the thickness direction (a positive C plate). Furthermore, each optically anisotropic layer may have a tilt orientation or may form a cholesteric orientation state.

[0059] When the retardation plate 20 is formed by bonding two or more types of retardation films having different orientations, they can be bonded via a third bonding layer 30c. The λ / 4 function over the entire visible light range preferably satisfies the optical characteristics shown in the following formula (1), where Re(λ) is the in-plane retardation value for light with a wavelength of λ nm, and more preferably satisfies the optical characteristics shown in the following formulas (1), (2), and (3).

[0060] 100nm<Re(550)<160nm (1) (wherein Re(550) represents an in-plane phase difference value (in-plane retardation) for light with a wavelength of 550nm.) Re(450) / Re(550)≦1.0 (2) 1.00≦Re(650) / Re(550) (3) (wherein Re(450) represents an in-plane phase difference value for light with a wavelength of 450nm, Re(550) represents an in-plane phase difference value for light with a wavelength of 550nm, and Re(650) represents an in-plane phase difference value for light with a wavelength of 650nm.) When "Re(450) / Re(550)" of a single retardation film exceeds 1.0, light leakage on the short wavelength side in an optical laminate including the retardation film increases. The value of "Re(450) / Re(550)" is preferably 0.7 or more and 1.0 or less, more preferably 0.80 or more and 0.95 or less, even more preferably 0.80 or more and 0.92 or less, and particularly preferably 0.82 or more and 0.88 or less. The value of "Re(450) / Re(550)" can be adjusted arbitrarily by adjusting the mixing ratio of the polymerizable liquid crystal compound, the lamination angle of the multiple retardation films, and the retardation value.

[0061] The in-plane retardation value of the retardation film can be adjusted by the thickness of the retardation film. Since the in-plane retardation value is determined by the following formula (4), a desired in-plane retardation value (Re(λ)) can be obtained by adjusting Δn(λ) and the thickness d. The thickness of the retardation film is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. The thickness of the retardation film can be measured using an interference film thickness meter, a laser microscope, or a stylus film thickness meter. Note that Δn(λ) depends on the molecular structure of the polymerizable liquid crystal compound described below.

[0062] Re(λ)=d×Δn(λ) (4) (In the formula, Re(λ) represents the in-plane retardation value at a wavelength of λ nm, d represents the thickness, and Δn(λ) represents the birefringence at a wavelength of λ nm.) The positive C plate is not particularly limited as long as it has anisotropy in the thickness direction, but if it does not have tilt orientation or cholesteric orientation, it has the optical characteristics represented by formula (5).

[0063] nx≈ny<nz (5) The in-plane retardation value Re(550) of the positive C plate at a wavelength of 550 nm is usually in the range of 0 to 10 nm, preferably in the range of 0 to 5 nm. Furthermore, the retardation value Rth(550) in the thickness direction at a wavelength of 550 nm is usually in the range of −170 nm or more and −10 nm or less, preferably −150 nm or more and −20 nm or less, and more preferably −100 nm or more and −40 nm or less. When the retardation value in the thickness direction is in this range, the anti-reflection properties from oblique directions can be further improved.

[0064] The polymerizable liquid crystal compound contained in the retardation film-forming composition refers to a liquid crystal compound having a polymerizable group, particularly a photopolymerizable group. Conventional polymerizable liquid crystal compounds can be used as the polymerizable liquid crystal compound. The photopolymerizable group refers to a group that can participate in a polymerization reaction by reactive species, such as active radicals or acids, generated from a photopolymerization initiator. Examples of the photopolymerizable group include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxiranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxiranyl groups, and oxetanyl groups are preferred, with acryloyloxy groups being more preferred. The liquid crystal property may be either thermotropic or lyotropic, but thermotropic liquid crystals are preferred due to the ability to precisely control the film thickness. Furthermore, the phase-ordered structure of the thermotropic liquid crystal may be either nematic or smectic. The polymerizable liquid crystal compound may be a rod-shaped liquid crystal or a discotic liquid crystal. The polymerizable liquid crystal compound may be used alone or in combination of two or more kinds.

[0065] As the polymerizable liquid crystal compound, from the viewpoint of exhibiting reverse wavelength dispersion, a liquid crystal having a T-shaped or H-shaped mesogenic structure that further has birefringence in a direction perpendicular to the molecular long axis direction is preferred, and from the viewpoint of obtaining stronger dispersion, a T-shaped liquid crystal is more preferred, and specific examples of the T-shaped liquid crystal structure include compounds represented by the following formula (I):

[0066]

[0067] In formula (I), Ar represents a divalent aromatic group which may have a substituent. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When the divalent group Ar contains two or more aromatic groups, the two or more aromatic groups may be bonded to each other via a divalent bonding group such as a single bond, -CO-O-, or -O-.

[0068] G １ and G ２ each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and a carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom.

[0069] L １ , L ２ , B １ and B ２ are each independently a single bond or a divalent linking group. k and l each independently represent an integer of 0 to 3, and satisfy the relationship 1≦k+l. Here, when 2≦k+l, B １ and B ２ , G １ and G ２ may be the same as or different from each other.

[0070] E １ and E ２ each independently represents an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and —CH ２ - may be substituted with -O-, -S-, or -COO-, and when there are a plurality of -O-, -S-, or -COO-, they are not adjacent to each other. １ and P ２ each independently represents a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

[0071] G１ and G ２ are each independently preferably a 1,4-phenylenediyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, or a 1,4-cyclohexanediyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a 1,4-phenylenediyl group substituted with a methyl group, an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group, and particularly preferably an unsubstituted 1,4-phenylenediyl group or an unsubstituted 1,4-trans-cyclohexanediyl group. １ and G ２ At least one of L is preferably a divalent alicyclic hydrocarbon group. １ or L ２ G binds to １ and G ２ It is more preferable that at least one of the groups is a divalent alicyclic hydrocarbon group.

[0072] L １ and L ２ are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, or —R ａ１ OR ａ２ -, -R ａ３ COOR ａ４ -, -R ａ５ OCOR ａ６ -, R ａ７ OC=OOR ａ８ -, -N=N-, -CR ｃ =CR ｄ - or -C≡C-, where R ａ１ ~R ａ８ each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms; R ｃ and R ｄ represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. １ and L ２ are each independently preferably a single bond, -OR ａ２－１ -, -CH ２ -, -CH ２ CH２ -, -COOR ａ４－１ - or OCOR ａ６－１ -, where R ａ２－１ , R ａ４－１ , R ａ６－１ are each independently a single bond, —CH ２ -, -CH ２ CH ２ - represents either １ and L ２ are each independently more preferably a single bond, —O—, or —CH ２ CH ２ -, -COO-, -COOCH ２ CH ２ - or OCO-.

[0073] B １ and B ２ are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, or —R ａ９ OR ａ１０ -, -R ａ１１ COOR ａ１２ -, -R ａ１３ OCOR ａ１４ - or R ａ１５ OC=OOR ａ１６ -, where R ａ９ ~R ａ１６ each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. １ and B ２ are each independently preferably a single bond, -OR ａ１０－１ -, -CH ２ -, -CH ２ CH ２ -, -COOR ａ１２－１ - or OCOR ａ１４－１ -, where R ａ１０－１ , R ａ１２－１ , R ａ１４－１ are each independently a single bond, —CH ２ -, -CH ２ CH ２ - represents either. １ and B ２ are each independently more preferably a single bond, —O—, or —CH ２ CH ２ -, -COO-, -COOCH２ CH ２ -, -OCO-, or OCOCH ２ CH ２ - is.

[0074] From the viewpoint of exhibiting reverse wavelength dispersion, k and l are preferably in the range of 2≦k+l≦6, preferably k+l=4, and more preferably k=2 and l=2. When k=2 and l=2, a symmetric structure is obtained, which is preferable.

[0075] E １ and E ２ are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms. １ or P ２ Examples of the polymerizable group represented by the formula (I) include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

[0076] Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring, with a benzene ring and a naphthalene ring being preferred. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferred, and a benzothiazole group is even more preferred. Furthermore, when Ar contains a nitrogen atom, it is preferred that the nitrogen atom has π electrons.

[0077] In formula (I), the total number N of π electrons contained in the divalent aromatic group represented by Ar π is preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. Also, it is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

[0078] Suitable examples of the aromatic group represented by Ar include the following groups:

[0079]

[0080] In formula (Ar-1) to formula (Ar-23), * represents a linking moiety, Z ０ , Z １ and Z ２ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N,N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms, or an N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

[0081] Q １ , Q ２ and Q ３ are each independently -CR ２′ R ３′ -, -S-, -NH-, -NR ２′ represents -, -CO- or O-, and R ２′ and R ３′ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0082] J １ , and J ２ each independently represents a carbon atom or a nitrogen atom. １ , Y ２ and Y ３ each independently represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group.

[0083] W １ and W ２ each independently represents a hydrogen atom, a cyano group, a methyl group, or a halogen atom, and m represents an integer of 0 to 6. １ , Y ２ and Y ３ Examples of the aromatic hydrocarbon group in the formula (I) include aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group, with a phenyl group and a naphthyl group being preferred, and a phenyl group being more preferred. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms and containing at least one heteroatom, such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group being preferred.

[0084] Y １ , Y ２ and Y ３ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

[0085] Z ０ , Z １ and Z ２ are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms; Z ０ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group; Z １ and Z ２ is more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

[0086] Q １ , Q ２ and Q ３ is -NH-, -S-, -NR ２′ -, -O- are preferred, and R ２′is preferably a hydrogen atom. Among these, —S—, —O—, and —NH— are particularly preferred. Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.

[0087] In formulae (Ar-16) to (Ar-23), Y １ is the nitrogen atom to which it is bonded and Z ０ and may form an aromatic heterocyclic group together. Examples of the aromatic heterocyclic group include those mentioned above as the aromatic heterocyclic ring that Ar may have, and examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. This aromatic heterocyclic group may have a substituent. １ is the nitrogen atom to which it is bonded and Z ０ and may be the above-mentioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group, such as a benzofuran ring, a benzothiazole ring, or a benzoxazole ring.

[0088] Among polymerizable liquid crystal compounds, compounds with a maximum absorption wavelength of 300 to 400 nm are preferred. When a polymerizable liquid crystal composition contains a photopolymerization initiator, there is a risk of polymerization and gelation of the polymerizable liquid crystal compound progressing during long-term storage. However, if the polymerizable liquid crystal compound has a maximum absorption wavelength of 300 to 400 nm, even if the composition is exposed to ultraviolet light during storage, the generation of reactive species from the photopolymerization initiator and the progression of polymerization and gelation of the polymerizable liquid crystal compound due to the reactive species can be effectively suppressed. This is advantageous in terms of long-term stability of the polymerizable liquid crystal composition, and the alignment and film thickness uniformity of the resulting retardation film can be improved. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured using a UV-visible spectrophotometer in a solvent. The solvent is a solvent capable of dissolving the polymerizable liquid crystal compound, such as chloroform.

[0089] Examples of the discotic polymerizable liquid crystal compound include a compound containing a group represented by formula (W) (hereinafter, also referred to as "polymerizable liquid crystal compound (W)").

[0090]

[0091] [In formula (W), R ４０ represents the following formulas (W-1) to (W-5).

[0092]

[0093] [In formulas (W-1) to (W-5), X ４０ and Z ４０ each independently represents an alkanediyl group having 1 to 12 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and a hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. ２ - may be replaced by -O- or -CO-. m2 represents an integer.] Examples of the rod-shaped polymerizable liquid crystal compound include compounds represented by formula (II), formula (III), formula (IV), formula (V), formula (VI) or formula (VII).

[0094] P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (II) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (III) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (IV) P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (V) P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (VI) P11-B11-E11-B12-A11-B13-A12-F11 (VII) [In formulas (II) to (VII), A11 to A14 each independently represent a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. Hydrogen atoms contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, or a nitro group, and hydrogen atoms contained in the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms may be substituted with a fluorine atom.]

[0095] B11 and B17 each independently represent —O—, —S—, —CO—O—, —O—CO—, —O—CO—O—, or —CO—NR １６ -, -NR １６ represents —CO—, —CO—, —CS—, or a single bond. １６ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0096] B12 to B16 each independently represent —C≡C—, —CH═CH—, or —CH ２ -CH ２ -, -O-, -S-, -C(=O)-, -C(=O)-O-, -OC(=O)-, -OC(=O)-O-, -CH=N-, -N=CH-, -N=N-, -C(=O)-NR １６ -, -NR １６ -C(=O)-, -OCH ２ -, -OCF ２ -, -CH ２ O-, -CF ２ represents O—, —CH═CH—C(═O)—O—, —O—C(═O)—CH═CH— or a single bond.

[0097] E11 and E12 each independently represent an alkanediyl group having 1 to 12 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and a hydrogen atom contained in the alkoxy group may be substituted with a halogen atom. ２ - may be replaced by -O- or -CO-.

[0098] F11 is a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxy group, a methylol group, a formyl group, a sulfo group (—SO ３ H), a carboxy group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and —CH composing the alkyl group and alkoxy group ２ - may be replaced by -O-.

[0099] P11 and P12 each independently represent a polymerizable group.] The content of the polymerizable liquid crystal compound in the retardation film-forming composition is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and even more preferably 90 to 95 parts by mass, relative to 100 parts by mass of the solid content of the retardation film-forming composition. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the alignment of the obtained retardation film. In this specification, the solid content of the polymerizable liquid crystal composition means all components of the polymerizable liquid crystal composition excluding volatile components such as organic solvents.

[0100] (3-2) Composition for Forming Retardation Film As described above, the composition for forming a retardation film contains a polymerizable liquid crystal compound. The composition for forming a retardation film may further contain reactive additives such as a solvent, a leveling agent, a polymerization initiator, a photosensitizer, a polymerization inhibitor, a crosslinking agent, and an adhesion agent, and it is preferable that the composition contains a solvent and a leveling agent from the viewpoint of processability.

[0101] The retardation film-forming composition may contain a solvent. Generally, polymerizable liquid crystal compounds have high viscosity, so that dissolving the composition in a solvent makes it easy to apply, and as a result, it often becomes easy to form a retardation film. The solvent is preferably one that can completely dissolve the polymerizable liquid crystal compound, and is also preferably a solvent that is inactive to the polymerization reaction of the polymerizable liquid crystal compound.

[0102] Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene, and nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more.

[0103] The content of the solvent is preferably 50 to 98% by mass relative to the total amount of the retardation film-forming composition. In other words, the content of the solids in the retardation film-forming composition is preferably 2 to 50% by mass, more preferably 5 to 30% by mass. When the content of the solids is 50% by mass or less, the viscosity of the retardation film-forming composition is low, and the thickness of the retardation film becomes approximately uniform, which tends to reduce the occurrence of unevenness in the retardation film. Furthermore, the content of the solids can be determined taking into consideration the thickness of the retardation film to be produced.

[0104] The retardation film-forming composition may contain a leveling agent. The leveling agent is an additive that adjusts the fluidity of the composition and has the function of making the film obtained by applying the composition flatter, and examples thereof include organically modified silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Among them, when horizontal alignment is desired, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferred, and when vertical alignment is desired, organically modified silicone-based leveling agents and perfluoroalkyl-based leveling agents are preferred.

[0105] When the retardation film-forming composition contains a leveling agent, the content thereof is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal compound, and the obtained retardation film tends to be smoother. When the content of the leveling agent relative to the polymerizable liquid crystal compound exceeds the above range, unevenness tends to occur in the obtained retardation film. The retardation film-forming composition may contain two or more types of leveling agents.

[0106] The retardation film-forming composition may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound or the like. As the polymerization initiator, a photopolymerization initiator that generates active radicals by the action of light is preferred, from the viewpoint that it is not dependent on the phase state of the thermotropic liquid crystal.

[0107] As the photopolymerization initiator, any known photopolymerization initiator can be used as long as it is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound.Specific examples include photopolymerization initiators that can generate active radicals or acids by the action of light, and among these, photopolymerization initiators that generate radicals by the action of light are preferred.The photopolymerization initiators can be used alone or in combination of two or more.

[0108] As the photopolymerization initiator, known photopolymerization initiators can be used. For example, photopolymerization initiators that generate active radicals include self-cleavage-type benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, and azo compounds, and hydrogen-abstraction-type benzophenone compounds, alkylphenone compounds, benzoin ether compounds, benzil ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, and triazine compounds. As photopolymerization initiators that generate acids, iodonium salts and sulfonium salts can be used. From the viewpoint of excellent reaction efficiency at low temperatures, self-cleavage type photopolymerization initiators are preferred, and acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are particularly preferred.

[0109] The content of the polymerization initiator in the retardation film-forming composition can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound, but is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, polymerization can be carried out without disturbing the alignment of the polymerizable liquid crystal compound.

[0110] The retardation film-forming composition may contain a sensitizer. The sensitizer is preferably a photosensitizer. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and alkoxy group-containing anthracenes (e.g., dibutoxyanthracene, etc.); phenothiazine, rubrene, etc.

[0111] When the retardation film-forming composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the retardation film-forming composition can be further accelerated. The amount of the sensitizer used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

[0112] From the viewpoint of stably progressing the polymerization reaction, the retardation film-forming composition may contain an antioxidant. The antioxidant can control the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound.

[0113] The antioxidant may be, for example, a primary antioxidant selected from a phenol-based antioxidant, an amine-based antioxidant, a quinone-based antioxidant, or a nitroso-based antioxidant, or a secondary antioxidant selected from a phosphorus-based antioxidant and a sulfur-based antioxidant.

[0114] When the retardation film-forming composition contains an antioxidant, the content of the antioxidant is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. The antioxidants can be used alone or in combination of two or more. When the content of the antioxidant is within the above range, polymerization can be carried out without disturbing the alignment of the polymerizable liquid crystal compound.

[0115] The retardation film-forming composition may contain a reactive additive. The reactive additive preferably has a carbon-carbon unsaturated bond, an active hydrogen reactive group, or a thiol group in its molecule. The "active hydrogen reactive group" referred to here includes a carboxyl group (-COOH), a hydroxyl group (-OH), an amino group (-NH ２ Representative examples of reactive groups include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, and a maleic anhydride group. The number of reactive groups possessed by the reactive additive is usually 1 to 20, and preferably 1 to 10.

[0116] (3-3) Substrate Examples of the substrate for forming the retardation film include glass substrates and film substrates, with film substrates being preferred, and long rolled films being more preferred in terms of continuous production. Examples of resins constituting the film substrate include linear polyolefins such as polyethylene and polypropylene; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid esters; polyacrylic acid esters; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide; and the like. Among these, from the viewpoint of transparency when used in optical film applications, a film substrate selected from triacetyl cellulose, cyclic olefin resins, polymethacrylic acid esters, and polyethylene terephthalate is more preferred.

[0117] Examples of commercially available cellulose ester substrates include "Fujitac Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (all manufactured by Konica Minolta Opto, Inc.). Examples of commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona (Germany)), "Arton" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (all manufactured by Zeon Corporation), and "Apel" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such cyclic olefin resins can be formed into a film by known means such as solvent casting or melt extrusion to form a substrate. Commercially available cyclic olefin resin substrates can also be used. Commercially available cyclic olefin resin substrates include "ESCINA" (registered trademark) and "SCA40" (registered trademark) (both manufactured by Sekisui Chemical Co., Ltd.), "ZEONORFILM" (registered trademark) (manufactured by Optes Co., Ltd.), and "ARTONFILM" (registered trademark) (manufactured by JSR Corporation).

[0118] The thickness of the substrate is preferably thin enough to allow practical handling, but if it is too thin, the strength decreases and processability tends to be poor. The thickness of the substrate is usually 5 μm to 300 μm, preferably 10 μm to 200 μm, and more preferably 10 to 50 μm. Furthermore, by peeling off the substrate and transferring the retardation film, a further thinning effect can be obtained.

[0119] (3-4) Alignment Film In this specification, the alignment film has an alignment regulating force that aligns the polymerizable liquid crystal compound in a desired direction.

[0120] The alignment film facilitates the alignment of the polymerizable liquid crystal compound. The alignment state of the liquid crystal, such as horizontal alignment, vertical alignment, hybrid alignment, or tilted alignment, varies depending on the properties of the alignment film and the polymerizable liquid crystal compound, and any combination thereof can be selected. For example, if the alignment film is made of a material that exerts horizontal alignment as an alignment control force, the polymerizable liquid crystal compound can form horizontal or hybrid alignment, while if the alignment film is made of a material that exerts vertical alignment, the polymerizable liquid crystal compound can form vertical or tilted alignment. The terms horizontal, vertical, and the like refer to the direction of the optical axis of the aligned polymerizable liquid crystal compound relative to the plane of the retardation film. For example, vertical alignment means that the optical axis of the aligned polymerizable liquid crystal compound is perpendicular to the plane of the retardation film. Here, vertical means 90°±20° relative to the plane of the retardation film.

[0121] When the alignment film is made of an alignment polymer, the alignment restraining force can be adjusted arbitrarily by the surface condition or rubbing conditions, and when it is made of a photoalignment polymer, the alignment restraining force can be adjusted arbitrarily by the polarized light irradiation conditions, etc. Furthermore, the liquid crystal alignment can also be controlled by selecting the physical properties of the polymerizable liquid crystal compound, such as the surface tension or liquid crystallinity.

[0122] The alignment film formed between the substrate and the retardation film is preferably insoluble in a solvent used when forming the retardation film on the alignment film, and has heat resistance in a heat treatment for removing the solvent and orienting the liquid crystal. Examples of the alignment film include an alignment film made of an orientable polymer, a photo-alignment film, a groove-alignment film, and a stretched film stretched in the alignment direction. When applied to a long rolled film, a photo-alignment film is preferred because the alignment direction can be easily controlled.

[0123] The thickness of the alignment film is usually in the range of 10 nm to 5000 nm, preferably in the range of 10 nm to 1000 nm, and more preferably in the range of 30 to 300 nm. Examples of alignment polymers used in rubbed alignment films include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule, and their hydrolyzates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Among these, polyvinyl alcohol is preferred. These alignment polymers may be used alone or in combination of two or more.

[0124] Rubbing methods include a method in which an oriented polymer film formed on the surface of a substrate by applying an oriented polymer composition to the substrate and annealing the composition is brought into contact with a rotating rubbing roll wrapped with a rubbing cloth.

[0125] The photo-alignment film is made of a polymer, oligomer, or monomer having a photoreactive group. The photo-alignment film can obtain an alignment control force by irradiating it with polarized light. The photo-alignment film is more preferable in that the direction of the alignment control force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0126] A photoreactive group refers to a group that exhibits liquid crystal alignment ability upon irradiation with light. Specifically, it is a group that undergoes a photoreaction that is the origin of liquid crystal alignment ability, such as molecular alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, which occurs upon irradiation with light. Among such photoreactive groups, those that undergo dimerization reaction or photocrosslinking reaction are preferred in terms of excellent alignment ability. As photoreactive groups capable of causing such reactions, those having an unsaturated bond, particularly a double bond, are preferred, and groups having at least one selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) are more preferred.

[0127] Examples of photoreactive groups having a C=C bond include vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups, and cinnamoyl groups. Chalcone groups and cinnamoyl groups are preferred from the viewpoints of easy control of reactivity and the development of alignment control force during photoalignment. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of photoreactive groups having an N=N bond include azobenzene groups, azonaphthalene groups, aromatic heterocyclic azo groups, bisazo groups, formazan groups, and groups having an azoxybenzene basic structure. Examples of photoreactive groups having a C=O bond include benzophenone groups, coumarin groups, anthraquinone groups, and maleimide groups. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

[0128] Polarized light irradiation can be performed by either irradiating the film surface directly with polarized light or by irradiating the film surface with polarized light from the substrate side and then transmitting the polarized light. It is particularly preferable that the polarized light be substantially parallel light. The wavelength of the polarized light to be irradiated should be in a wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) with a wavelength of 250 to 400 nm is particularly preferable. Examples of light sources used for polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF. High-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are more preferable. These lamps are preferred because of the high emission intensity of ultraviolet light with a wavelength of 313 nm. Polarized light can be irradiated by irradiating light from the light source through an appropriate polarizer. Examples of such polarizers include polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire-grid polarizers.

[0129] (4) Bonding Layer (4-1) First Bonding Layer The first bonding layer 30a is a pressure-sensitive adhesive layer or an adhesive layer, and is preferably a pressure-sensitive adhesive layer. The first bonding layer 30a bonds the polarizer 101 and the retardation film 20. That is, the first bonding layer 30a is in direct contact with the polarizer 101 and the retardation film 20.

[0130] The thickness of the first bonding layer 30a is, for example, 0.5 μm or more and 25 μm or less. The upper limit of the range is preferably 20 μm, more preferably 18 μm. The lower limit of the range is preferably 1 μm, more preferably 3 μm.

[0131] When the thickness of the first bonding layer 30a is within the above numerical range, the thickness of the first bonding layer 30a becomes relatively thin. The distance between the image display element 40 and the polarizer 101 becomes shorter, which makes it easier to prevent the end of the polarizer 101 from swelling up. The thickness of the first bonding layer 30a may be, for example, greater than 10 μm. However, in terms of further reducing the thickness, the thickness is preferably 10 μm or less, and particularly preferably 7 μm or less.

[0132] The first bonding layer 30a may have light selective absorption properties. That is, the first bonding layer 30a may contain a light absorber. A preferred light absorber is an ultraviolet absorber. (4-2) Second Bonding Layer The second bonding layer 30b is a pressure-sensitive adhesive layer or an adhesive layer, and is preferably a pressure-sensitive adhesive layer. The second bonding layer 30b bonds the optical laminate 1 to, for example, an image display element 40 or the like.

[0133] The thickness of the second bonding layer 30b is, for example, 5 μm or more and 30 μm or less. The upper limit of the range is preferably 25 μm, more preferably 20 μm. The lower limit of the range is preferably 10 μm.

[0134] The second bonding layer 30b may have photoselective absorption properties. That is, the second bonding layer 30b may contain a light absorber. A preferred light absorber is an ultraviolet absorber. (4-3) Third Bonding Layer The third bonding layer 30c is a pressure-sensitive adhesive layer or an adhesive layer, and is preferably an adhesive layer. More preferably, it is an adhesive layer formed by curing an active energy ray-curable adhesive, and even more preferably, it is an adhesive layer formed by curing an ultraviolet-curable adhesive. When the third bonding layer 30c is an adhesive layer, it is possible to prevent wrinkles from occurring in the cured liquid crystal layer when the circularly polarizing plate is bent or folded. The third bonding layer 30c bonds the first cured liquid crystal layer 201 and the second cured liquid crystal layer 202.

[0135] The retardation plate 20 may have light-selective absorption properties. For example, the third bonding layer 30c may contain a light absorber. A preferred light absorber is an ultraviolet absorber. The thickness of the third bonding layer 30c is, for example, 0.5 μm or more and 4.5 μm or less. The upper limit of the above range is preferably 3.5 μm, more preferably 2.5 μm. The lower limit of the above range is preferably 1 μm, more preferably 1.5 μm.

[0136] When the thickness of the third bonding layer 30c is 0.5 μm or more, it is possible to improve the adhesion to the first cured liquid crystal layer 201 and the second cured liquid crystal layer 202. When the thickness of the third bonding layer 30c is 4.5 μm or less, it is possible to easily suppress the bulging of the end portion of the polarizer 101.

[0137] (4-4) Pressure-sensitive Adhesive Layer As the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer, any conventionally known pressure-sensitive adhesive composition having excellent optical transparency can be used without particular limitation. For example, a pressure-sensitive adhesive composition having a base polymer such as an acrylic resin, a urethane resin, a silicone resin, or a polyvinyl ether resin can be used. Active energy ray-curable pressure-sensitive adhesive compositions, heat-curable pressure-sensitive adhesive compositions, etc. are also suitable. Among these, pressure-sensitive adhesive compositions having an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability, weather resistance, heat resistance, etc., are preferred. The pressure-sensitive adhesive composition may further contain a crosslinker, a silane compound, an antistatic agent, etc.

[0138] [(Meth)acrylic Resin] The (meth)acrylic resin contained in the pressure-sensitive adhesive composition is preferably a polymer (hereinafter also referred to as a "(meth)acrylic acid ester polymer") having as its main component (for example, 50 parts by mass or more per 100 parts by mass of the structural unit of the (meth)acrylic resin) a structural unit derived from a (meth)acrylic acid alkyl ester represented by the following formula (Ia) (hereinafter also referred to as a "structural unit (Ia)"):

[0139] In this specification, the term "(meth)acrylic resin" means either an acrylic resin or a methacrylic resin, and the "(meth)" in (meth)acrylate has the same meaning.

[0140]

[0141] [In the formula, R １０ represents a hydrogen atom or a methyl group, R ２０represents an alkyl group having 1 to 20 carbon atoms, and the alkyl group may have any of a linear, branched, or cyclic structure, and a hydrogen atom of the alkyl group may be substituted with an alkoxy group having 1 to 10 carbon atoms.] Examples of the (meth)acrylic acid ester represented by formula (Ia) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, i-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n Examples of alkoxy group-containing alkyl acrylates include 2-methoxyethyl (meth)acrylate and ethoxymethyl (meth)acrylate. Specific examples of alkoxy group-containing alkyl acrylates include 2-methoxyethyl (meth)acrylate and ethoxymethyl (meth)acrylate. Of these, n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate is preferred, and n-butyl (meth)acrylate is particularly preferred.

[0142] The (meth)acrylic acid ester polymer may contain a structural unit derived from a monomer other than the structural unit (Ia). The structural unit derived from the other monomer may be one type or two or more types. Examples of the other monomer that the (meth)acrylic acid ester polymer may contain include a monomer having a polar functional group, a monomer having an aromatic group, and an acrylamide-based monomer.

[0143] Examples of the monomer having a polar functional group include (meth)acrylates having a polar functional group, such as a hydroxy group, a carboxy group, an unsubstituted or substituted amino group substituted with an alkyl group having 1 to 6 carbon atoms, and a heterocyclic group such as an epoxy group.

[0144] The content of the structural units derived from the monomer having a polar functional group in the (meth)acrylic acid ester polymer is preferably 10 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, even more preferably 0.5 parts by mass or more and 5 parts by mass or less, and particularly preferably 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of all structural units of the (meth)acrylic acid ester polymer.

[0145] Examples of the monomer having an aromatic group include a (meth)acrylic acid ester having one (meth)acryloyl group and one or more aromatic rings (e.g., a benzene ring, a naphthalene ring, etc.) in the molecule, and having a phenyl group, a phenoxyethyl group, or a benzyl group. By including these structural units, it is possible to suppress the white spots that occur in polarizing plates in high-temperature and high-humidity environments.

[0146] The content of the structural units derived from the monomer having an aromatic group in the (meth)acrylic acid ester polymer is preferably 20 parts by mass or less, more preferably 4 parts by mass or more and 20 parts by mass or less, and even more preferably 4 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of all structural units of the (meth)acrylic acid ester polymer.

[0147] Examples of acrylamide monomers include N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, N-(2-methylpropoxymethyl)acrylamide, etc. By including these structural units, it is possible to suppress the bleed-out of additives such as antistatic agents, which will be described later.

[0148] Furthermore, structural units derived from monomers other than the structural unit (Ia) may include structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, structural units derived from monomers having multiple (meth)acryloyl groups in the molecule, and the like.

[0149] The weight-average molecular weight (hereinafter also simply referred to as "Mw") of the (meth)acrylic resin (1) is preferably 500,000 to 2,500,000. A weight-average molecular weight of 500,000 or more can improve the durability of the first pressure-sensitive adhesive layer in high-temperature, high-humidity environments. A weight-average molecular weight of 2,500,000 or less improves operability when applying a coating liquid containing the pressure-sensitive adhesive composition. The molecular weight distribution (Mw / Mn), expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (hereinafter also simply referred to as "Mn"), is usually 2 to 10. In this specification, "weight-average molecular weight" and "number-average molecular weight" are polystyrene-equivalent values ​​measured by gel permeation chromatography (GPC).

[0150] When the (meth)acrylic resin is dissolved in ethyl acetate to form a 20% by mass solution, the viscosity at 25°C is preferably 20 Pa·s or less, and more preferably 0.1 to 15 Pa·s. When the viscosity of the (meth)acrylic resin at 25°C is within this range, it contributes to improved durability and reworkability of a polarizing plate including a pressure-sensitive adhesive layer formed from the resin. The viscosity can be measured using a Brookfield viscometer.

[0151] The glass transition temperature (Tg) of the (meth)acrylic resin is, for example, −60 to 20° C., preferably −50 to 15° C., more preferably −45 to 10° C., and even more preferably −40 to 0° C. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

[0152] The (meth)acrylic resin may contain two or more types of (meth)acrylic acid ester polymers. Examples of such (meth)acrylic acid ester polymers include (meth)acrylic acid ester polymers having a relatively low molecular weight, such as those containing the structural unit (Ia) derived from the (meth)acrylic acid ester as a main component, and having a weight-average molecular weight in the range of 50,000 to 300,000.

[0153] (Meth)acrylic resins can usually be produced by known polymerization methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. In producing (meth)acrylic resins, polymerization is usually carried out in the presence of a polymerization initiator. The amount of polymerization initiator used is usually 0.001 to 5 parts by mass per 100 parts by mass of the total of all monomers constituting the (meth)acrylic resin. (Meth)acrylic resins can also be produced by a method of polymerization using active energy rays such as ultraviolet rays.

[0154] [Crosslinking Agent] The pressure-sensitive adhesive composition preferably contains a crosslinking agent. Examples of the crosslinking agent include conventional crosslinking agents (e.g., isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, peroxides, etc.), and isocyanate compounds are particularly preferred from the viewpoints of the pot life of the pressure-sensitive adhesive composition, crosslinking rate, and durability of the polarizing plate.

[0155] The isocyanate compound is a compound having at least two isocyanato groups (—NCO) in the molecule. Specific examples include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. Other examples include adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, as well as dimers and trimers of these isocyanate compounds. Two or more isocyanate compounds may be used in combination.

[0156] The proportion of the crosslinking agent relative to 100 parts by mass of the (meth)acrylic resin is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 1 part by mass.

[0157] [Silane Compound] The pressure-sensitive adhesive composition may further contain a silane compound. Examples of the silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0158] The silane compound may also contain an oligomer derived from the silane compound. The content of the silane compound in the pressure-sensitive adhesive composition is typically 0.01 to 10 parts by mass, and preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth)acrylic resin. When the content of the silane compound is 0.01 part by mass or more, the adhesion between the pressure-sensitive adhesive layer and the adherend tends to be improved, and when the content is 10 parts by mass or less, bleeding out of the silane compound from the pressure-sensitive adhesive layer tends to be suppressed.

[0159] [Antistatic Agent] The pressure-sensitive adhesive composition may further contain an antistatic agent. Examples of the antistatic agent include known agents, and ionic antistatic agents are preferred. Examples of the cationic component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of organic cations include pyridinium cation, imidazolium cation, ammonium cation, sulfonium cation, phosphonium cation, etc. Examples of inorganic cations include alkali metal cations such as lithium cation, potassium cation, sodium cation, and cesium cation, and alkaline earth metal cations such as magnesium cation and calcium cation. The anionic component constituting the ionic antistatic agent may be either an inorganic anion or an organic anion, but is preferably an anionic component containing a fluorine atom in terms of excellent antistatic performance. Examples of the anionic component containing a fluorine atom include hexafluorophosphate anion (PF ６ － ), bis(trifluoromethanesulfonyl)imide anion [(CF ３ SO ２ ) ２ N － ], bis(fluorosulfonyl)imide anion [(FSO ２ ) ２ N － ] anions and the like.

[0160] An ionic antistatic agent that is solid at room temperature is preferred in that it provides excellent stability over time of the antistatic performance of the PSA composition. The content of the antistatic agent is, for example, 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 1 to 7 parts by mass, relative to 100 parts by mass of the (meth)acrylic resin.

[0161] The pressure-sensitive adhesive composition may contain one or more additives such as an ultraviolet absorber, a solvent, a crosslinking catalyst, a tackifier, a plasticizer, etc. It is also useful to blend an ultraviolet-curable compound into the pressure-sensitive adhesive composition, form a pressure-sensitive adhesive layer, and then cure it by irradiating it with ultraviolet light to form a harder pressure-sensitive adhesive layer.

[0162] The pressure-sensitive adhesive layer can be formed, for example, by dissolving or dispersing the pressure-sensitive adhesive composition in a solvent to prepare a solvent-containing pressure-sensitive adhesive composition, which is then applied to the surface of the layer on which the pressure-sensitive adhesive layer is to be formed, and drying.

[0163] The thickness of the pressure-sensitive adhesive layer is usually 0.1 to 30 μm, preferably 3 to 30 μm, and more preferably 5 to 25 μm. (4-5) Adhesive Layer The adhesive layer can be formed from an adhesive composition.

[0164] Examples of adhesive compositions include aqueous adhesive compositions and curable adhesive compositions that cure upon heating or irradiation with active energy rays such as ultraviolet light, visible light, electron beams, and X-rays. Examples of aqueous adhesive compositions include those in which a polyvinyl alcohol resin or a urethane resin is dissolved in water as the main component, and those in which a polyvinyl alcohol resin or a urethane resin is dispersed in water as the main component. The aqueous adhesive composition may further contain a curable component or crosslinking agent such as a polyaldehyde, a melamine compound, a zirconia compound, a zinc compound, a glyoxal compound, or a water-soluble epoxy resin. Examples of aqueous adhesive compositions include the adhesive composition described in JP 2010-191389 A, the adhesive composition described in JP 2011-107686 A, the composition described in JP 2020-172088 A, and the composition described in JP 2005-208456 A.

[0165] The curable adhesive composition is preferably an active energy ray-curable adhesive composition that contains a curable (polymerizable) compound as a main component and is cured by irradiation with active energy rays. Examples of the active energy ray-curable adhesive composition include a cationic polymerization adhesive composition that contains a cationic polymerizable compound as the curable compound, a radical polymerization adhesive composition that contains a radical polymerizable compound as the curable compound, and a hybrid adhesive composition that contains both a cationic polymerizable compound and a radical polymerizable compound as the curable compound.

[0166] The cationically polymerizable compound is a compound or oligomer that undergoes a cationic polymerization reaction and hardens when exposed to active energy rays such as ultraviolet light, visible light, electron beams, or X-rays or when heated, and specific examples thereof include epoxy compounds, oxetane compounds, and vinyl compounds.

[0167] Examples of epoxy compounds include alicyclic epoxy compounds (compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule) such as 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate; aromatic epoxy compounds (compounds having an aromatic ring and an epoxy group in the molecule) such as diglycidyl ether of bisphenol A; and aliphatic epoxy compounds (compounds having at least one oxirane ring bonded to an aliphatic carbon atom in the molecule) such as 2-ethylhexyl glycidyl ether and 1,4-butanediol diglycidyl ether.

[0168] Examples of the oxetane compound include compounds having one or more oxetane rings in the molecule, such as 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane.

[0169] The cationic polymerization adhesive composition preferably contains a cationic polymerization initiator. The cationic polymerization initiator may be a thermal cationic polymerization initiator or a photo-induced cationic polymerization initiator. Examples of cationic polymerization initiators include aromatic diazonium salts such as benzenediazonium hexafluoroantimonate; aromatic iodonium salts such as diphenyliodonium tetrakis(pentafluorophenyl)borate; aromatic sulfonium salts such as triphenylsulfonium hexafluorophosphate; and iron-arene complexes such as xylene-cyclopentadienyliron(II) hexafluoroantimonate. The content of the cationic polymerization initiator is typically 0.1 to 10 parts by mass per 100 parts by mass of the cationic polymerizable compound. Two or more types of cationic polymerization initiators may be used.

[0170] Examples of the cationic polymerization adhesive composition include the cationic polymerization compositions described in JP 2016-126345 A, WO 2019 / 10315 A, and JP 2021-113969 A.

[0171] The radical polymerizable compound is a compound or oligomer that undergoes a radical polymerization reaction and hardens when exposed to active energy rays such as ultraviolet light, visible light, electron beams, or X-rays or when heated, and specific examples thereof include compounds having an ethylenically unsaturated bond. Examples of the compound having an ethylenically unsaturated bond include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule and vinyl compounds having one or more vinyl groups in the molecule.

[0172] Examples of the (meth)acrylic compound include (meth)acrylate monomers and (meth)acrylamide monomers each having at least one (meth)acryloyloxy group in the molecule, and (meth)acryl group-containing compounds such as (meth)acrylic oligomers obtained by reacting two or more functional group-containing compounds and each having at least two (meth)acryloyl groups in the molecule. In this specification, (meth)acryloyl means either acryloyl or methacryloyl.

[0173] The radical polymerization adhesive composition preferably contains a radical polymerization initiator. The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator. Examples of the radical polymerization initiator include acetophenone-based initiators such as acetophenone and 3-methylacetophenone; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; xanthone, fluorenone, and the like. The content of the radical polymerization initiator is typically 0.1 to 10 parts by mass per 100 parts by mass of the radical polymerizable compound. Two or more types of radical polymerization initiators may be contained.

[0174] Examples of radical polymerization adhesive compositions include the radical polymerizable compositions described in JP 2016-126345 A, JP 2016-153474 A, and WO 2017 / 183335 A.

[0175] The active energy ray-curable adhesive composition may contain additives such as an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow adjuster, a plasticizer, an antifoaming agent, an antistatic agent, a leveling agent, and a solvent, as needed.

[0176] The bonding of two layers with an adhesive layer can be carried out by applying an adhesive composition to at least one of the bonding surfaces selected from the bonding surfaces of each of the two layers, overlapping the two layers with the coating layer of the adhesive composition interposed therebetween, pressing them together from above and below using a bonding roll or the like, and then drying the adhesive layer, curing it by irradiating it with active energy rays, or curing it by heating.

[0177] Before forming the coating layer of the adhesive layer, at least one of the bonding surfaces of the two layers may be subjected to an easy-adhesion treatment such as saponification treatment, corona treatment, plasma treatment, primer treatment, anchor coating treatment, etc.

[0178] To form a coating layer of the adhesive composition, various coating methods can be used, such as a die coater, a comma coater, a gravure coater, a wire bar coater, or a doctor blade coater.

[0179] The light irradiation intensity when irradiating with active energy rays is determined depending on the composition of the active energy ray-curable adhesive composition and is not particularly limited, but is preferably 10 mW / cm ２ 1,000mW / cm or more ２ The irradiation intensity is preferably an intensity in a wavelength region effective for activating a photocationic polymerization initiator or a photoradical polymerization initiator. Irradiation is performed once or multiple times at such a light irradiation intensity, and the cumulative light amount is 10 mJ / cm or less. ２ It is preferable that the dose is 100 mJ / cm or more. ２ 1,000mJ / cm or more ２ It is more preferable to set the following:

[0180] The light source used to polymerize and cure the active energy ray-curable adhesive composition is not particularly limited, but examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0181] The thickness of the adhesive layer formed from the aqueous adhesive composition may be, for example, 5 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less, and may be 0.01 μm or more, and preferably 0.05 μm or more.

[0182] The thickness of the adhesive layer formed from the active energy ray-curable adhesive composition may be, for example, 10 μm or less, preferably 5 μm or less, and more preferably 3 μm or less, and may be 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1 μm or more.

[0183] (5) Surface Protective Film The surface protective film is provided on the surface of the polarizer 101 for the purpose of preventing the surface of the polarizer 101 from being soiled or scratched. The surface protective film may be a resin film for surface protective film on which the above-mentioned pressure-sensitive adhesive layer is formed, or may be a self-adhesive film formed alone. The thickness of the surface protective film can be, for example, 30 μm or more and 200 μm or less, preferably 30 μm or more and 150 μm or less, and more preferably 30 μm or more and 120 μm or less.

[0184] After the optical laminate 1 is bonded to an image display element such as a liquid crystal cell or other optical component, the surface protection film is peeled off and removed together with the adhesive layer contained in the surface protection film, or the resin film for the surface protection film is peeled off and removed while the adhesive layer remains on the surface of the polarizer.

[0185] The surface protection film may contain an antistatic agent. The antistatic agent may be contained in, for example, the pressure-sensitive adhesive layer. Instead of or in addition to containing an antistatic agent in the pressure-sensitive adhesive layer, an antistatic layer containing an antistatic agent may be provided on the surface of the resin film for surface protection film opposite to the surface on which the pressure-sensitive adhesive layer is laminated.

[0186] The antistatic agent may be an ionic compound. The ionic compound is a compound having an inorganic or organic cation and an inorganic or organic anion. Two or more types of ionic compounds may be used.

[0187] The adhesion strength of the surface protection film to the optical laminate 1 at a temperature of 23°C and a relative humidity of 55% is preferably 0.01 N / 25 mm or more, more preferably 0.03 N / 25 mm or more, and even more preferably 0.08 N / 25 mm or more, and is preferably 0.5 N / 25 mm or less, more preferably 0.4 N / 25 mm or less, and even more preferably 0.3 N / 25 mm or less.

[0188] The adhesion strength can be measured by the following procedure. A test piece is prepared by cutting the laminate with the surface protective film into a rectangle of an arbitrary size and laminating it to a glass substrate or the like. This evaluation sample is subjected to a 180° peel test at a moving speed of 300 mm / min in accordance with JIS K6854-2:1999 "Adhesives - Peel adhesion strength test method - Part 2: 180° peel", and the peel strength measured is taken as the adhesion strength.

[0189] When the surface protection film is a resin film for surface protection film having an adhesive layer provided thereon, the thickness of this adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more, and is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

[0190] Examples of resins constituting the resin film for surface protection films include polyolefin resins such as polyethylene resins and polypropylene resins; cyclic polyolefin resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; and (meth)acrylic resins. Among these, polyester resins such as polyethylene terephthalate are preferred. The resin film for surface protection films may have a single-layer structure or a multi-layer structure of two or more layers. The resin film for surface protection films may be a film that has been subjected to a stretching treatment such as uniaxial stretching or biaxial stretching.

[0191] The above-mentioned surface protection film can be obtained by forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive to the surface of a resin film for surface protection film, followed by drying, etc. A self-adhesive film that can be used as a surface protection film is a film that can adhere by itself and maintain its adhesion state without the need for a means for adhering a pressure-sensitive adhesive layer, etc. The self-adhesive film can be formed using, for example, a polypropylene-based resin, a polyethylene-based resin, etc.

[0192] (6) Image display device The image display device includes an optical laminate and an image display element (such as an organic EL display element). The optical laminate is disposed on the viewing side of the image display element. The optical laminate can be attached to the image display element using a pressure-sensitive adhesive layer.

[0193] The image display device is not particularly limited, and examples thereof include organic electroluminescence (organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, and electroluminescence display devices.

[0194] The image display device can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signs, measuring instruments or meters, office equipment, medical equipment, computing equipment, and the like.

[0195] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" in the examples mean % by mass and parts by mass, respectively.

[0196] <Measurement and Evaluation Methods> (1) Measurement of boron content of polarizer 0.2 g of polarizer was dissolved in 200 g of a 1.9 mass % mannitol aqueous solution. The resulting aqueous solution was titrated with a 1 mol / L NaOH aqueous solution, and the boron content (mass %) of the polarizer was calculated by comparing the amount of NaOH solution required for neutralization with a calibration curve. The results are shown in Table 5.

[0197] (2) Calculation of boric acid cross-linking index The cross section of the polarizing plate was processed using an ultramicrotome (trade name "LEICA Ultramicrotome EM UC7i" manufactured by LEICA Corporation). The cross section of the obtained polarizing plate was measured at the center position in the thickness direction of the polarizer using a laser Raman spectrophotometer (trade name "NRS-5100" manufactured by JASCO Corporation) under the following conditions at a wave number of 780 cm. －１ Raman scattering intensity at wavenumber 850 cm －１ The Raman scattered light intensities at these wavenumbers were then calculated and divided by the Raman scattered light intensities at the wavenumber 780 cm －１ Raman scattering light intensity at wavenumber 850 cm －１ The boric acid crosslinking index was calculated from the Raman scattered light intensity at 1000 kJ / cm2.

[0198] Excitation wavelength: 532 nm Grating: 600 l / mm Slit width: 100 x 1000 μm Aperture: φ40 μm Objective lens: 100x Objective lens: 100x (3) Measurement of moisture permeability of peelable film The moisture permeability was measured in accordance with JIS Z 0208. The temperature and humidity conditions were a temperature of 40°C and a relative humidity of 90% RH.

[0199] (4) Measurement of luminosity-corrected single transmittance and luminosity-corrected polarization The single transmittance and luminosity-corrected polarization of the optical laminate were measured using an integrating sphere spectrophotometer (V7100, manufactured by JASCO Corporation) by irradiating linearly polarized light from a prism onto the polarizer side of the optical laminate. MD transmittance and TD transmittance were determined in the wavelength range of 380 nm to 780 nm, and the single transmittance and polarization degree at each wavelength were calculated based on formulas (A) and (B). Furthermore, luminosity correction was performed using a 2-degree visual field (illuminant C) according to JIS Z8701 to determine the luminosity-corrected single transmittance (Ty) and luminosity-corrected polarization degree (Py). Note that "MD transmittance" refers to the transmittance when the direction of polarized light exiting a Glan-Thompson prism is parallel to the transmission axis of the polarizing plate sample. In formulas (A) and (B), "MD transmittance" is represented as "MD." Furthermore, the "TD transmittance" is the transmittance when the direction of the polarized light exiting the Glan-Thompson prism is perpendicular to the transmission axis of the polarizing plate sample, and in formulas (A) and (B), the "TD transmittance" is represented as "TD."

[0200] Single transmittance (%) = (MD + TD) / 2 Formula (A) Polarization degree (%) = {(MD - TD) / (MD + TD)} × 100 Formula (B) (5) Weather resistance test of optical laminate The optical laminate obtained in the examples was cut into a square measuring 30 mm x 30 mm. At this time, the cutting was performed so that the absorption axis of the polarizer and the sides of the square were parallel. The cut optical laminate was bonded to a 40 mm x 40 mm alkali-free glass (manufactured by Corning, product number: EAGLE XG (registered trademark)) via a pressure-sensitive adhesive layer (2) to prepare an evaluation sample. The luminous efficacy-corrected polarization degree Py was measured for each evaluation sample.

[0201] Next, the evaluation sample was placed on an aluminum plate (reflector) so that ultraviolet light was irradiated from the polarizer side, and then placed in a Sunshine Weather Meter (manufactured by Suga Test Instruments Co., Ltd.) for 240 hours under conditions of a black panel temperature of 63°C and a relative humidity of 50% to perform a weather resistance test. After the test, the luminosity-corrected polarization degree Py of the evaluation sample was measured. The absolute value ΔPy of the difference between the luminosity-corrected polarization degree Py before and after the test was calculated.

[0202] (6) Edge swelling test of optical laminate The optical laminate obtained in the examples was cut into a rectangle measuring 100 mm x 50 mm so that the absorption axis of the polarizer was parallel to the long side. The cut optical laminate was attached to a 0.7 mm thick alkali-free glass (manufactured by Corning, product number: EAGLE XG (registered trademark)) via an adhesive to prepare a sample for evaluation. A heat resistance test was performed in which the evaluation sample was stored in a dryer at a temperature of 105°C for 30 minutes, and the sample after the test was stored in an environment of 23°C and 55% humidity for 30 minutes, after which the "height difference of edge deformation" was measured.

[0203] "Height difference of edge deformation" Figure 4 shows an evaluation sample. For the measurement, a three-dimensional microscope "PLμ2300" manufactured by Sensofar was used in confocal mode to determine the deformation height over a width of 800 μm from the edge (A) of the center of the short side of the polarizing plate to the in-plane (A') toward the in-plane center (see Figure 4). The objective lens magnification during measurement was 20x. Figure 5 shows an example of the results of measuring the deformation height from the edge (A) of the polarizing plate toward the in-plane (A'). A negative value for the deformation height means that the optical laminate bonded to the alkali-free glass is deforming toward the alkali-free glass side. A positive value for the deformation height means that the optical laminate bonded to the alkali-free glass is deforming toward the opposite side from the alkali-free glass side. From the obtained results, the difference between the maximum and minimum values ​​of the deformation height was calculated as the "height difference of edge deformation."

[0204] The evaluation criteria for the edge swelling are as follows: ⊚ (Excellent): The difference in height of the edge deformation is less than 3 μm. ⊚ (Good): The difference in height of the edge deformation is 3 μm or more and less than 5 μm.

[0205] ◯ (Acceptable): The height difference of the end deformation is 5 μm or more and less than 7 μm. × (Not Acceptable): The height difference of the end deformation is 7 μm or more. (7) Measurement of absorbance of laminate A laminate was produced by laminating the first bonding layer 30a, the first cured liquid crystal layer 201, the third bonding layer 30c, the second cured liquid crystal layer 202, and the second bonding layer 30b. The laminate was bonded to glass via the second bonding layer 30b. A cycloolefin polymer (COP) film (ZF-14 manufactured by Zeon Corporation) was bonded to the first cured liquid crystal layer 201 via the first bonding layer 30a. In this way, a laminate for evaluation was produced.

[0206] The evaluation laminate was set in a spectrophotometer UV-2450 (manufactured by Shimadzu Corporation), and the absorbance was measured in the wavelength range of 300 to 800 nm in 1 nm steps using the double beam method. The absorbance at a wavelength of 340 nm of the prepared laminate is shown in Table 5. The absorbance at a wavelength of 340 nm of both the glass alone and the COP film alone was 0.

[0207] <Preparation of Components of Optical Laminate> (1) Preparation of Polarizer (1) A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2400, and a degree of saponification of 99% or more was uniaxially stretched to a draw ratio of 4.6 times on a heated roll, and while maintaining the tension, was immersed in a dye bath containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water at 28° C. for 60 seconds.

[0208] Next, the film was immersed in a boric acid aqueous solution 1 containing 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at 65°C for 110 seconds. Next, the film was immersed in a boric acid aqueous solution 2 containing 2.3 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at 68°C for 30 seconds. Thereafter, the film was washed with pure water at 10°C and dried to obtain a polarizer (1). The polarizer (1) had a thickness of 8 μm and a boron content of 3.2% by mass. The boric acid crosslinking index was 0.8.

[0209] (2) Preparation of Polarizer (2) A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2,400, and a degree of saponification of 99% or more was uniaxially stretched to a draw ratio of 4.6 times on a heated roll, and while maintaining the tension, was immersed in a dye bath containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water at 28° C. for 60 seconds.

[0210] Next, the film was immersed in a boric acid aqueous solution 1 containing 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at 65°C for 110 seconds. Next, the film was immersed in a boric acid aqueous solution 2 containing 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water at 68°C for 30 seconds. Thereafter, the film was washed with pure water at 10°C and dried to obtain a polarizer (2). The polarizer (2) had a thickness of 8 μm and a boron content of 4.3% by mass. The boric acid crosslinking index was 1.2.

[0211] (3) Preparation of Polarizer (3) Polarizer (3) was obtained in the same manner as polarizer (2), except that the stretching ratio was changed to 4.1, the temperature of boric acid aqueous solution 1 was changed to 64° C., and the temperature of boric acid aqueous solution 2 was changed to 67° C. The polarizer (3) had a thickness of 8 μm, a boron content of 4.3 mass%, and a boric acid crosslinking index of 1.1.

[0212] (4) Preparation of Release Film, Protective Film, and Surface Protective Film The following release films, protective films, and surface protective films were prepared. Release Film A: TD80UL, a triacetyl cellulose film manufactured by Fujifilm Corporation. It had a thickness of 80 μm and a moisture permeability of 502 g / m2·24 hr. Protective Film B: A COP film with a thickness of 23 μm. It did not absorb ultraviolet light. Surface Protective Film C: A 15 μm thick acrylic pressure-sensitive adhesive layer was formed on a 38 μm thick polyester resin film to prepare a 53 μm thick surface protective film C having a pressure-sensitive adhesive layer.

[0213] (5) Preparation of Linear Polarizing Plate (1) A peelable film A was attached to both sides of the prepared polarizer (1) via pure water using a roll laminator, and then the film was dried at 80°C for 3 minutes to obtain a linear polarizing plate (1) having the peelable film A on both sides of the polarizer (1).

[0214] The release films A on both sides of the linear polarizing plate (1) were peeled off and removed, and the luminous efficiency-corrected single transmittance measured for the polarizer (1) alone was 42.3%, and the luminous efficiency-corrected polarization degree was 99.99%. (6) Preparation of Linear Polarizing Plate (2) A linear polarizing plate (2) was prepared in the same manner as the linear polarizing plate (1), except that the polarizer (1) was changed to the polarizer (2).

[0215] The release films A on both sides of the linear polarizing plate (2) were peeled off and removed, and the luminous efficiency-corrected single transmittance measured for the polarizer (2) alone was 42.4%, and the luminous efficiency-corrected polarization degree was 99.98%. (7) Preparation of Linear Polarizing Plate (3) A protective film B was attached to one side of the prepared polarizer (3) via a water-based adhesive, and a release film A was attached to the opposite side of the protective film B via pure water using a roll laminator, followed by drying at 80°C for 3 minutes to obtain a linear polarizing plate (3). The linear polarizing plate (3) was obtained by laminating the release film A, the polarizer (3), an adhesive layer, and the protective film B in this order.

[0216] (8) Cured Liquid Crystal Layer A The following retardation film (Z1) was prepared as the second cured liquid crystal layer A. The following retardation film (Z2) was prepared as the first cured liquid crystal layer A.

[0217] [Preparation of Oriented Polymer Composition (1)] Water was added to commercially available polyvinyl alcohol (polyvinyl alcohol 1000 fully saponified type, manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was heated at 100°C for 1 hour to obtain an oriented polymer composition (1).

[0218] [Production of Polymerizable Liquid Crystal Compounds] Polymerizable liquid crystal compounds (A1) and (A2) having the structures shown below were prepared in the same manner as described in JP-A-2010-244038.

[0219] Polymerizable liquid crystal compound (A1): a compound represented by the following formula:

[0220]

[0221] Polymerizable liquid crystal compound (A2): a compound represented by the following formula:

[0222]

[0223] [Preparation of Retardation Layer-Forming Composition (Y1)] A polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF Japan), a leveling agent "BYK-361N" (manufactured by BYK-Chemie), and a photopolymerization initiator "Omnirad 907" (manufactured by IGM Resin B.V.) were added. Further, propylene glycol 1-monomethyl ether 2-acetate (PGME) was added, and the mixture was stirred at a temperature of 80°C for 1 hour to prepare a retardation layer-forming composition (Y1).

[0224]

[0225] Polymerizable liquid crystal compound LC242: a compound represented by the following formula

[0226]

[0227] [Preparation of retardation layer forming composition (Y2)] The polymerizable liquid crystal compound (A1) and the polymerizable liquid crystal compound (A2) were mixed in a mass ratio of 80:20 to obtain a mixture. To 100 parts of the obtained mixture, parts of a leveling agent "Megafac F-556" (manufactured by DIC Corporation), parts of a photopolymerization initiator "Omnirad 907" (manufactured by IGM Resin BV), and an ionic compound (B) were added. Furthermore, cyclopentanone was added, and the mixture was stirred at a temperature of 80 ° C. for 1 hour to prepare a retardation layer forming composition (Y2).

[0228]

[0229] Ionic compound (B): a compound represented by the following formula:

[0230]

[0231] [Preparation of Retardation Film (Z1)] An oriented polymer composition (1) was applied to a rectangular cut-out triacetyl cellulose film (TAC) (KC4UY, manufactured by Konica Minolta, Inc.), and after heating and drying, an oriented polymer film having a thickness of 100 nm was formed. The surface of the obtained oriented polymer film was subjected to a rubbing treatment at an angle of 15° from the longitudinal direction of the TAC, and a retardation layer-forming composition (Y1) was applied thereon using a bar coater. The obtained coating film was dried at 100°C for 1 minute and then cooled to room temperature to obtain a dried coating. Next, using a high-pressure mercury lamp ("Uniqure VB-15201BY-A" manufactured by Ushio Inc.), an exposure dose of 1000 mJ / cm was applied under a nitrogen atmosphere. ２ The dried coating was irradiated with ultraviolet light (365 nm standard) to form a retardation layer (X1) in which the polymerizable liquid crystal compound was cured in a state of being aligned horizontally relative to the substrate plane, thereby obtaining a retardation film (Z1) consisting of TAC / alignment film / retardation layer (X1) (horizontally aligned liquid crystal cured film). The thickness of the obtained retardation layer (X1) was measured using a laser microscope and found to be 1.0 μm. The in-plane retardation value was measured using a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. As a result, the in-plane retardation value at a wavelength of 550 nm was found to be Re(550) = 140 nm. Note that the retardation value of TAC at a wavelength of 550 nm is approximately 0, so there is no effect on the optical properties. The orientation angle was 15° relative to the longitudinal direction of the TAC.

[0232] [Preparation of Retardation Film (Z2)] A rectangular cut-out cycloolefin polymer (COP) (ZF14, manufactured by Zeon Corporation) was subjected to corona treatment using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.), and then an oriented polymer composition (1) was applied thereto. After heating and drying, an oriented polymer film having a thickness of 100 nm was formed. The surface of the obtained oriented polymer film was subjected to rubbing treatment at an angle of 75° from the longitudinal direction of the COP, and then a retardation layer-forming composition (Y2) was applied thereto using a bar coater. The obtained coating film was dried at 120 ° C. for 2 minutes, and then exposed to 1000 mJ / cm at 80 ° C. under a nitrogen atmosphere using a high-pressure mercury lamp ("Uniqure VB-15201BY-A" manufactured by Ushio Inc.). ２The dried coating was irradiated with ultraviolet light (365 nm standard) to form a cured retardation layer (X2) in a state in which the optical axis of the polymerizable liquid crystal compound was aligned horizontally relative to the substrate plane, thereby obtaining a retardation film (Z2) consisting of COP / alignment film / retardation layer (X2). The thickness of the obtained retardation layer (X2) was measured using a laser microscope and found to be 1.8 μm. The in-plane retardation value was measured using a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. As a result, the in-plane retardation value at a wavelength of 550 nm was found to be Re(550) = 270 nm. Note that the retardation value of the COP at a wavelength of 550 nm was approximately 0, so there was no effect on the optical properties. The orientation angle was 75° relative to the longitudinal direction of the COP.

[0233] (9) Preparation of active energy ray-curable adhesive A The following components were blended and mixed, and then degassed to prepare active energy ray-curable adhesive A.

[0234] [Cationically polymerizable compound] Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX Corporation) 30 parts by mass 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (trade name: OXT-221, manufactured by Toagosei Co., Ltd.) 13 parts by mass Bisphenol A type epoxy resin (trade name: EP-4100E, manufactured by ADEKA Corporation, viscosity 13 Pa s (temperature 25°C)) 45 parts by mass Aromatic-containing oxetane compound (trade name: TCM-104, manufactured by TRONLY) 12 parts by mass [Photocationic polymerization initiator] CPI-100P, manufactured by San-Apro Co., Ltd., 50% propylene carbonate solution 2.25 parts by mass (solid content) [Photosensitizing aid] 1,4-diethoxynaphthalene 1 part by mass (10) Preparation of Retardation Plate A with Substrate Layer Corona treatment was performed on the surface of the first liquid crystal cured layer A (½ wavelength retardation layer) on the substrate layer and the surface of the second liquid crystal cured layer A (¼ wavelength retardation layer) on the substrate layer. The corona-treated surfaces of these two retardation layers were bonded together using the active energy ray-curable adhesive A prepared above so that the angle between the slow axes of these two retardation layers was 60°. Thereafter, an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to irradiate the retardation plate A from the ¼ wavelength retardation layer side with an integrated light amount of 400 mJ / cm.２ The active energy ray-curable adhesive A was cured by ultraviolet irradiation with UV-B to form an adhesive layer. The lamination was performed using a laminator, and the active energy ray-curable adhesive A was applied so that the thickness of the adhesive layer after curing was 2 μm. This resulted in a retardation plate A with a substrate layer, in which the substrate layer, alignment layer, ½ wavelength retardation layer (first liquid crystal cured layer), adhesive layer (third laminating layer), ¼ wavelength retardation layer (second liquid crystal cured layer), alignment layer, and substrate layer were laminated in this order. The total thickness of the ½ wavelength retardation layer (first liquid crystal cured layer), adhesive layer (third laminating layer), and ¼ wavelength retardation layer (second liquid crystal cured layer) was 4.8 μm.

[0235] (11) Preparation of first liquid crystal cured layer B The following retardation film (Z) was prepared as the first liquid crystal cured layer B. [Preparation of composition (X) for forming a photo-alignment film] A photo-alignment material (weight average molecular weight: 50,000, m:n = 50:50) having the following structure was produced in accordance with the method described in JP 2021-196514 A. Two parts of the photo-alignment material and 98 parts of cyclopentanone (solvent) were mixed as components, and the resulting mixture was stirred at 80°C for one hour to prepare a composition (X) for forming a photo-alignment film.

[0236] Photoalignment material: Compound represented by the following formula

[0237]

[0238] [Production of polymerizable liquid crystal compounds] Polymerizable liquid crystal compound (A3) and polymerizable liquid crystal compound (A4) having the structures shown below were prepared. Polymerizable liquid crystal compound (A3) was prepared in the same manner as the method described in JP-A 2019-003177. Polymerizable liquid crystal compound (A4) was prepared in the same manner as the method described in JP-A 2009-173893.

[0239] Polymerizable liquid crystal compound (A3): a compound represented by the following formula:

[0240]

[0241] Polymerizable liquid crystal compound (A4): a compound represented by the following formula:

[0242]

[0243] A solution was obtained by dissolving 1 mg of polymerizable liquid crystal compound (A3) in 10 mL of chloroform. The obtained solution was placed in a measurement cell with an optical path length of 1 cm, and the measurement sample was placed in an ultraviolet-visible spectrophotometer (Shimadzu Corporation, "UV-2450") to measure the absorption spectrum. The wavelength at which the maximum absorbance was obtained was read from the obtained absorption spectrum, and the maximum absorption wavelength λmax in the wavelength range of 300 to 400 nm was 356 nm.

[0244] [Preparation of retardation layer-forming composition (Y)] The polymerizable liquid crystal compound (A3) and the polymerizable liquid crystal compound (A4) were mixed in a mass ratio of 90:10 to obtain a mixture. To 100 parts of the obtained mixture, 0.1 parts of a leveling agent "BYK-361N" (manufactured by BM Chemie) and 3 parts of a photopolymerization initiator "Irgacure OXE-03" (manufactured by BASF Japan Co., Ltd.) were added. Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solids concentration was 13%. This mixture was stirred at a temperature of 80 ° C. for 1 hour to prepare a retardation layer-forming composition (Y).

[0245]

[0246] [Preparation of Retardation Film (Z)] The photo-alignment film-forming composition (X) was applied to a biaxially stretched polyethylene terephthalate (PET) film (Diafoil, manufactured by Mitsubishi Plastics, Inc.) as a substrate C using a bar coater. The resulting coating film was dried at 120°C for 2 minutes and then cooled to room temperature to form a dry coating. Thereafter, a UV irradiation device (SPOT CURE SP-9, manufactured by Ushio Inc.) was used to irradiate the film with 100 mJ of polarized ultraviolet light (313 nm standard) to obtain a photo-alignment film D. The film thickness of the photo-alignment film D, measured using an ellipsometer M-220 manufactured by JASCO Corporation, was 100 nm.

[0247] The retardation layer-forming composition (Y) was applied onto the obtained photo-alignment film D using a bar coater to form a coating film. This coating film was dried by heating at 120°C for 2 minutes and then cooled to room temperature to obtain a dried film. Next, using a high-pressure mercury lamp ("Uniqure VB-15201BY-A" manufactured by Ushio Inc.), the exposure dose was 500 mJ / cm under a nitrogen atmosphere. ２The dried coating was irradiated with ultraviolet light of wavelength 365 nm (reference wavelength), forming a retardation layer in which the polymerizable liquid crystal compound was cured in a state of being aligned horizontally relative to the substrate surface, thereby obtaining a retardation film (Z) consisting of substrate C / photo-aligned film D / retardation layer (cured horizontally aligned liquid crystal film). The thickness of the retardation layer measured using a laser microscope LEXT OLS4100 manufactured by Olympus Corporation was 2.0 μm.

[0248] The liquid crystal side of the retardation film (Z) was subjected to corona treatment, and the film was attached to glass via a 25 μm pressure-sensitive adhesive manufactured by Lintec Corporation, and the PET film was peeled off and removed. The in-plane retardation values ​​were measured using a KOBRA-WR manufactured by Oji Scientific Instruments. The in-plane retardation values ​​for light with wavelengths of 450 nm, 550 nm, and 650 nm were calculated using Cauchy's dispersion formula obtained from the measurement results of the in-plane retardation values ​​for light with wavelengths of 448.2 nm, 498.6 nm, 548.4 nm, 587.3 nm, 628.7 nm, and 748.6 nm.

[0249] As a result, the in-plane retardation values ​​were Re(450)=122 nm, Re(550)=140 nm, and Re(650)=144 nm, and the relationship between the in-plane retardation values ​​at each wavelength was as follows:

[0250] Re(450) / Re(550)=0.87 Re(650) / Re(550)=1.03 (In the formulae, Re(450) represents the in-plane retardation value for light with a wavelength of 450 nm, Re(550) represents the in-plane retardation value for light with a wavelength of 550 nm, and Re(650) represents the in-plane retardation value for light with a wavelength of 650 nm.) (12) Preparation of Second Liquid Crystal Cured Layer B The following retardation film (1) was prepared as the second liquid crystal cured layer B.

[0251] The retardation layer-forming composition (1) was prepared by mixing a photopolymerizable nematic liquid crystal compound (RMM28B, manufactured by Merck) and a solvent so that the solid content was 1 to 1.5 g. The solvent used was a mixed solvent obtained by mixing methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) in a mass ratio (MEK:MIBK:CHN) of 35:30:35.

[0252] A polyethylene terephthalate (PET) film having a thickness of 38 μm was prepared as a substrate layer. A composition for forming a vertical alignment film was applied to one surface of the substrate layer to a thickness of 3 μm, and the applied amount was 200 mJ / cm ２ The liquid crystal was irradiated with ultraviolet light of 1000 kJ / cm to form a vertical alignment film.

[0253] The retardation layer-forming composition (1) was applied onto the vertical alignment film by die coating. The applied amount was 4 to 5 g (wet). The coating film was dried at a drying temperature of 75°C for 120 seconds. Thereafter, the coating film was irradiated with ultraviolet (UV) rays to polymerize the polymerizable liquid crystal compound.

[0254] In this way, a retardation film (1) was obtained in which a layer of a cured polymerizable liquid crystal compound (second liquid crystal cured layer B), a vertical alignment film, and a base layer were laminated in this order. The second liquid crystal cured layer B was a positive C plate. The total thickness of the second liquid crystal cured layer B and the alignment film was 4 μm.

[0255] (13) Preparation of Active Energy Ray-Curable Adhesive B The components shown below were mixed to prepare an active energy ray-curable adhesive B. 3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation): 70 parts by mass Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Corporation): 20 parts by mass 2-Ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation): 10 parts by mass Cationic polymerization initiator (trade name: CPI-100_50% solution, manufactured by San-Apro Co., Ltd.): 4.5 parts by mass (actual solid content 2.25 parts by mass) 1,4-diethoxynaphthalene: 2 parts by mass (14) Preparation of retardation plate B with substrate layer The first liquid crystal cured layer B and the second liquid crystal cured layer B were bonded with an active energy ray-curable adhesive B (thickness 1 μm) so that the liquid crystal cured layer surfaces (the surfaces opposite to the substrate film) became bonding surfaces. The active energy ray-curable adhesive B was cured by irradiating it with ultraviolet light to obtain a substrate layer-attached retardation plate B in which the substrate layer, alignment layer, first liquid crystal cured layer B, adhesive layer (third laminating layer), second liquid crystal cured layer B, alignment layer, and substrate layer were laminated in this order. The thickness of the retardation laminate including the first liquid crystal cured layer B, adhesive layer (third laminating layer), and second liquid crystal cured layer B was 7 μm. The substrate layer-attached retardation plate B has ultraviolet absorption properties.

[0256] (15) Preparation of Adhesive Layer The following adhesive layer was prepared. [Adhesive Layer (1A)] (1-1) Preparation of Acrylic Resin Solution (1A) A reaction vessel equipped with a cooling tube, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 100 parts of ethyl acetate, 99.0 parts of butyl acrylate, 0.5 parts of 2-hydroxyethyl acrylate, and 0.5 parts of acrylic acid. The air inside the vessel was purged with nitrogen gas to remove oxygen, and the internal temperature was raised to 55°C. Thereafter, the entire amount of a solution prepared by dissolving 0.12 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added. After the addition of the polymerization initiator, the temperature was maintained for 1 hour. Subsequently, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr while maintaining the internal temperature at 54-56°C. When the concentration of the (meth)acrylic resin reached 35% by mass, the addition of ethyl acetate was stopped, and the vessel was then maintained at this temperature for a further 6 hours from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, to prepare an acrylic resin solution (1A). The resulting acrylic resin had a weight average molecular weight Mw of 1.7 million and a molecular weight distribution Mw / Mn of 3.9. Mw and Mn were measured using a GPC system equipped with a TSKgel GMH column manufactured by Tosoh Corporation. ＨＲ Two ion exchangers (e.g., 100-1500-H(S)) were connected in series, and tetrahydrofuran was used as the eluent. Measurements were performed in terms of standard polystyrene under the following conditions: sample concentration 2 mg / mL, sample introduction amount 100 μL, temperature 40°C, and flow rate 1 mL / min.

[0257] (1-2) Preparation of adhesive composition (1A) (1-1) To 80 parts of the solid content of the acrylic resin solution (1A) obtained in (1-1), 20 parts (solid content) of bifunctional acrylate (obtained from Shin-Nakamura Chemical Co., Ltd.; product number "A-DOG"), 2.5 parts of a crosslinking agent (manufactured by Mitsui Chemicals: trade name "D-101E" (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass))) based on the active ingredient, 1.5 parts of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name "Irgacure 500"), 0.3 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added, and ethyl acetate was added to the solid content concentration of 13% to obtain an adhesive composition (1A).

[0258] A-DOG is a diacrylate of an acetal compound of hydroxypivalaldehyde and trimethylolpropane, and has the following structure:

[0259]

[0260] (1-3) Preparation of Pressure-Sensitive Adhesive Sheet (1A) The pressure-sensitive adhesive composition (1A) prepared in (1-2) above was applied to the release-treated surface of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRV (V04) (thickness: 38 μm)] using an applicator so that the thickness after drying would be 5 μm, and the coating was dried at 100°C for 1 minute to prepare a pressure-sensitive adhesive layer. Next, the surface of the resulting pressure-sensitive adhesive layer opposite the separator film was bonded to the release-treated surface of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRF (thickness: 38 μm)]. Subsequently, ultraviolet light was irradiated under the following conditions to prepare a pressure-sensitive adhesive sheet (1A) as the pressure-sensitive adhesive layer (1A).

[0261] <UV irradiation conditions> Fusion UV lamp system (manufactured by Fusion UV Systems) H bulb used, cumulative light intensity 250 mJ / cm ２[Adhesive Layer (1B)] (2-1) Preparation of Acrylic Resin (A-1) A reaction vessel equipped with a cooling tube, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 86.4 parts ethyl acetate as a solvent, 61.9 parts butyl acrylate, and 1.9 parts 2-hydroxyethyl acrylate. The air in the vessel was replaced with nitrogen gas to remove oxygen, and the internal temperature was raised to 60°C. Subsequently, a solution of 0.4 parts azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts ethyl acetate was added in its entirety. The resulting mixture was maintained at 60°C for 1 hour, and then, while maintaining the internal temperature at 50-70°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr. When the concentration of the acrylic resin reached 35%, the addition of ethyl acetate was stopped, and the mixture was maintained at this temperature for 12 hours from the start of the ethyl acetate addition. Finally, ethyl acetate was added to adjust the concentration of the acrylic resin to 20%, and an ethyl acetate solution of the acrylic resin was prepared. The resulting acrylic resin had a weight average molecular weight (Mw) of 600,000 in terms of polystyrene measured by GPC, and an Mw / Mn ratio of 7.0. This resin was designated acrylic resin (A-1). The glass transition temperature measured by DSC was −52.9° C.

[0262] An ethyl acetate solution of acrylic resin (A-1) (resin concentration: 20%) was mixed with 0.5 parts of a crosslinker (Coronate L, solids content 75%: manufactured by Tosoh), 0.5 parts of a silane compound (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.), and 3.7 parts of a compound (light-selective absorber) represented by the following formula (aa2), which is described as the light-selective absorbing compound (2) in Synthesis Example 2 described in paragraph

[0142] of JP 2019-007001 A, and 2-butanone was added to give a solids concentration of 14%, to obtain a pressure-sensitive adhesive composition (1). The amount of the crosslinker (Coronate L) is expressed in parts by mass as the active ingredient.

[0263]

[0264] The pressure-sensitive adhesive composition (1) prepared above was applied to the release-treated surface of a release-treated polyethylene terephthalate film (SP-PLR382050 manufactured by Lintec Corporation, hereinafter abbreviated as "separator") using an applicator so that the thickness of the pressure-sensitive adhesive layer after drying would be 5 μm, and the applied film was dried at 100° C. for 1 minute to prepare a pressure-sensitive adhesive layer. The resulting pressure-sensitive adhesive layer was designated pressure-sensitive adhesive layer (1B) (hereinafter also referred to as photoselective absorbing pressure-sensitive adhesive 1). As shown in Table 4, the content of the light-selective absorbing agent per unit area of ​​the photoselective absorbing pressure-sensitive adhesive 1 was 0.2 (g / m ２ ) was.

[0265]

[0266] The light-selective absorbing pressure-sensitive adhesive layer of this example is formed from a pressure-sensitive adhesive composition containing at least a (meth)acrylic resin and a light-selective absorbing compound. The pressure-sensitive adhesive composition preferably further contains a crosslinking agent.

[0267] The light-selective absorption compound is not particularly limited as long as it is a compound that selectively absorbs light with a wavelength of 340 nm. Examples of compounds that selectively absorb light with a wavelength of 340 nm include ultraviolet absorbers. The ultraviolet absorber is not particularly limited, but examples include organic ultraviolet absorbers such as oxybenzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid ester-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. More specific examples include 5-chloro-2-(3,5-di-sec-butyl-2-hydroxylphenyl)-2H-benzotriazole, (2-2H-benzotriazol-2-yl)-6-(straight-chain and side-chain dodecyl)-4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, and 2,4-benzyloxybenzophenone. These organic ultraviolet absorbers may be used alone or in combination of two or more.

[0268] The ultraviolet absorber may be a commercially available product. Examples of triazine-based ultraviolet absorbers include "Kemisorb 102" manufactured by Chemipro Chemical Co., Ltd., "ADK STAB LA46" and "ADK STAB LAF70" manufactured by ADEKA Corporation, and "TINUVIN 109," "TINUVIN 171," "TINUVIN 234," "TINUVIN 326," "TINUVIN 327," "TINUVIN 328," "TINUVIN 928," "TINUVIN 400," "TINUVIN 460," "TINUVIN 405," and "TINUVIN 477" manufactured by BASF Japan Ltd. Examples of benzotriazole-based ultraviolet absorbers include "ADK STAB LA31" and "ADK STAB LA36" manufactured by ADEKA CORPORATION; "SUMISORB 200," "SUMISORB 250," "SUMISORB 300," "SUMISORB 340," and "SUMISORB 350" manufactured by Sumika Chemtex Co., Ltd.; "Kemisorb 74," "Kemisorb 79," and "Kemisorb 279" manufactured by Chemipro Chemical Co., Ltd.; and "TINUVIN 99-2," "TINUVIN 900," and "TINUVIN 928" manufactured by BASF.

[0269] The ultraviolet absorber may also be an inorganic ultraviolet absorber. Examples of inorganic ultraviolet absorbers include titanium oxide, zinc oxide, indium oxide, tin oxide, talc, kaolin, calcium carbonate, titanium oxide-based composite oxides, zinc oxide-based composite oxides, ITO (tin-doped indium oxide), and ATO (antimony-doped tin oxide). Examples of titanium oxide-based composite oxides include zinc oxide doped with silica and alumina. These inorganic ultraviolet absorbers can be used alone or in combination of two or more. Furthermore, an organic ultraviolet absorber and an inorganic ultraviolet absorber may be used in combination.

[0270] The weight average molecular weight (Mw) of the (meth)acrylic resin for forming the pressure-sensitive adhesive layer is a weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC) under the following conditions.

[0271] [Measurement conditions] GPC measurement apparatus: HLC-8020 manufactured by Tosoh Corporation GPC column (passed in the following order): TSK guard column HXL-H, TSK gel GMHXL (x 2), TSK gel G2000HXL manufactured by Tosoh Corporation Measurement solvent: tetrahydrofuran Measurement temperature: 40 ° C. [Adhesive layer (1C)] The amount of the light-selective absorber was 4.8 parts, and the thickness of the adhesive layer after drying was 17 μm. Except for this, the adhesive layer (1C) (hereinafter also referred to as light-selective absorbing adhesive 2) was prepared in the same manner as the adhesive layer (1B). As shown in Table 4, the content of the light-selective absorber per unit area of ​​the light-selective absorbing adhesive 2 was 0.9 (g / m ２ ) was.

[0272] [Adhesive Layer (1D)] An adhesive layer (1B) (hereinafter also referred to as light-selective absorbing adhesive 3) was produced in the same manner as for the adhesive layer (1B), except that the blending amount of the light-selective absorber was 6.3 parts and the thickness of the adhesive layer after drying was 17 μm. As shown in Table 4, the content of the light-selective absorber per unit area of ​​the light-selective absorbing adhesive 3 was 1.2 (g / m ２ ) was.

[0273] [Adhesive Layer (2)] (3-1) Preparation of Acrylic Resin Solution (2) A reaction vessel equipped with a cooling tube, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 81.8 parts of ethyl acetate, 90.0 parts of butyl acrylate, 5.0 parts of methyl acrylate, and 5.0 parts of acrylic acid. The air in the vessel was replaced with nitrogen gas to remove oxygen, and the internal temperature was raised to 55 ° C. Subsequently, a solution of 0.15 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added in its entirety. After the addition of the polymerization initiator, the temperature was maintained for 1 hour, and then ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr while maintaining the internal temperature at 54-56 ° C. The addition of ethyl acetate was stopped when the concentration of the (meth)acrylic resin reached 35% by mass, and the temperature was maintained for a further 6 hours from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, thereby preparing acrylic resin solution 2. The resulting acrylic resin had a weight average molecular weight Mw of 1.6 million and a molecular weight distribution Mw / Mn of 4.5. Mw and Mn were measured using a GPC system equipped with a TSKgel GMH column manufactured by Tosoh Corporation. ＨＲ Two ion exchangers (e.g., 100-1500-H(S)) were connected in series, and tetrahydrofuran was used as the eluent. Measurements were performed in terms of standard polystyrene under the following conditions: sample concentration 2 mg / mL, sample introduction amount 100 μL, temperature 40°C, and flow rate 1 mL / min.

[0274] (3-2) Preparation of Pressure-Sensitive Adhesive Composition (2) To 100 parts of the solid content of the acrylic resin solution (2) obtained in (3-1), 0.15 parts on an active ingredient basis of (Mitsui Chemicals: trade name "D-101E" (an ethyl acetate solution of a trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass))) and 0.2 parts of a silane coupling agent (Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added, and ethyl acetate was further added to adjust the solid content concentration to 13%, thereby obtaining a pressure-sensitive adhesive composition (2).

[0275] (3-3) Preparation of Pressure-Sensitive Adhesive Sheet (2) The pressure-sensitive adhesive composition (2) prepared in (3-2) above was applied to the release-treated surface of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRV (V04) (thickness: 38 μm)] using an applicator so that the thickness after drying would be 15 μm, and the pressure-sensitive adhesive layer was prepared by drying for 1 minute at 100° C. Next, the surface of the obtained pressure-sensitive adhesive layer opposite the separator film was bonded to the release-treated surface of a release-treated polyethylene terephthalate film [manufactured by Mitsubishi Chemical: MRF (thickness: 38 μm)] to prepare a pressure-sensitive adhesive sheet (2) as the pressure-sensitive adhesive layer (2).

[0276] <Preparation of Optical Laminate> <Example 1> The substrate layer and alignment layer on the half-wave retardation layer side of the substrate layer-attached retardation plate A prepared above were peeled off to expose the half-wave retardation layer. The release film A on one side of the linear polarizer (1) prepared above was peeled off. The exposed half-wave retardation layer and the polarizer (1) exposed by peeling off the release film A of the linear polarizer (1) were bonded together using a pressure-sensitive adhesive layer (1A) as a first bonding layer. The half-wave retardation layer and the linear polarizer (1) were bonded together so that the angle between the slow axis of the half-wave retardation layer and the transmission axis of the polarizer (1) was 15°. Subsequently, the release film A on the other side was peeled off from the linear polarizer (1) to expose the polarizer (1). The exposed polarizer (1) was bonded to the pressure-sensitive adhesive layer of the surface protective film C. Next, the alignment layer and the base layer on the quarter-wave retardation layer side were peeled off, and the pressure-sensitive adhesive layer (2) serving as the second bonding layer was bonded to the exposed quarter-wave retardation layer to obtain an optical laminate (1). Each bonding surface was subjected to a corona treatment.

[0277] Example 2 An optical laminate (2) was obtained in the same manner as in Example 1, except that the linear polarizing plate (1) was replaced with the linear polarizing plate (2).

[0278] Example 3 An optical laminate (3) was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive layer (1B) was used as the first attaching layer instead of the pressure-sensitive adhesive layer (1A).

[0279] Example 4 An optical laminate (4) was obtained in the same manner as in Example 2, except that the pressure-sensitive adhesive layer (1B) was used as the first attaching layer instead of the pressure-sensitive adhesive layer (1A).

[0280] Example 5 An optical laminate (5) was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive layer (1C) was used as the first attaching layer instead of the pressure-sensitive adhesive layer (1A).

[0281] Example 6 An optical laminate (6) was obtained in the same manner as in Example 2, except that the pressure-sensitive adhesive layer (1C) was used as the first attaching layer instead of the pressure-sensitive adhesive layer (1A).

[0282] Example 7 An optical laminate (7) was obtained in the same manner as in Example 2, except that the pressure-sensitive adhesive layer (1D) was used as the first attaching layer instead of the pressure-sensitive adhesive layer (1A).

[0283] Example 8 The substrate layer (substrate C) on the first liquid crystal cured layer B side of the substrate layer-attached retardation plate B prepared above was peeled off to expose the alignment layer (photo-alignment film D). The release film A on one side of the linear polarizing plate (2) prepared above was peeled off. The exposed alignment layer (photo-alignment film D) and the polarizer (2) exposed by peeling off the release film A of the linear polarizing plate (2) were bonded together using a pressure-sensitive adhesive layer (1A) as a first bonding layer. The retardation plate B and the linear polarizing plate (2) were bonded together such that the angle between the slow axis of the first liquid crystal cured layer B and the transmission axis of the polarizer (2) was 45°. Subsequently, the release film A on the other side was peeled off from the linear polarizing plate (2) to expose the polarizer (2). The exposed polarizer (2) was bonded to the pressure-sensitive adhesive layer of the surface protective film C. Next, the substrate layer on the second liquid crystal cured layer B side was peeled off to expose the alignment layer (vertical alignment film), and the pressure-sensitive adhesive layer 2 was attached to the alignment layer to obtain an optical laminate 8. Each of the attachment surfaces was subjected to a corona treatment.

[0284] Comparative Example 1 The substrate layer and alignment layer on the half-wave retardation layer side of the substrate layer-attached retardation plate A prepared above were peeled off to expose the half-wave retardation layer. The exposed half-wave retardation layer was bonded to the protective film B side of the linear polarizer (3) using a pressure-sensitive adhesive layer (1A). The half-wave retardation layer and the linear polarizer (3) were bonded together so that the angle between the slow axis of the half-wave retardation layer and the transmission axis of the polarizer (3) was 15°. Next, the release film A of the linear polarizer (3) was peeled off to expose the polarizer (3). The exposed polarizer (3) was bonded to the pressure-sensitive adhesive layer of the surface protective film C. Next, the alignment layer and substrate layer on the quarter-wave retardation layer side were peeled off, and the pressure-sensitive adhesive layer (2), which is a second bonding layer, was bonded to the exposed quarter-wave retardation layer to obtain an optical laminate (9). Each bonding surface was subjected to a corona treatment.

[0285] For the obtained optical laminate, the surface protective film C was peeled off together with the pressure-sensitive adhesive layer thereof, and then the above-mentioned weather resistance test was performed. The results are shown in Table 5. For the obtained optical laminate, the surface protective film C was peeled off together with the pressure-sensitive adhesive layer thereof, and then the above-mentioned edge swelling test was performed. The results are shown in Table 6.

[0286]

[0287]

[0288] DESCRIPTION OF SYMBOLS 1... Optical laminate 101... Polarizer 20... Retardation plate 201... First liquid crystal cured layer 202... Second liquid crystal cured layer 30a... First bonding layer 30b... Second bonding layer 30c... Third bonding layer 40... Image display element 109... Optical film including pressure-sensitive adhesive layer

Claims

1. An optical laminate comprising, in this order, an optical film including an adhesive layer, a polarizer in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, a first bonding layer, a retardation plate, and a second bonding layer, wherein the adhesive layer side of the optical film is in direct contact with the polarizer, the polarizer is in direct contact with the first bonding layer, and the layer formed by the first bonding layer, the retardation plate, and the second bonding layer has an absorbance of 0.1 or more for light with a wavelength of 340 nm.

2. The optical laminate according to claim 1, wherein the boron content of the polarizer is 0.5 mass % or more.

3. An optical laminate according to claim 1 or 2, wherein the luminosity-corrected single transmittance of the polarizer is 41% or more, and the luminosity-corrected polarization degree of the polarizer is 99.5% or more.

4. The optical laminate according to claim 1 or 2, wherein the retardation plate is made of a liquid crystal cured layer.

5. The optical laminate according to claim 1 or 2, wherein the retardation plate is a λ / 4 retardation plate exhibiting reverse wavelength dispersion.

6. The optical laminate according to claim 1 or 2, wherein the first bonding layer is a pressure-sensitive adhesive layer.

7. The optical laminate according to claim 1 or 2, wherein the first bonding layer contains an ultraviolet absorbing agent.

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