Optical stack

Abstract

The present invention provides an optical laminate that can suppress the disappearance of dichroic dyes from linear polarizers and suppress the reduction in visibility due to unevenness. [Solution] The optical laminate comprises a first protective layer, a linear polarizer, an adhesive layer, and a phase difference layer laminate in this order. The adhesive layer has a storage modulus of 0.2 to 1.0 MPa at 25°C and a thickness of 2 to 25 μm. The phase difference layer laminate comprises a first liquid crystal phase difference layer, an adhesive layer having a thickness of 20 to 200 nm, and a second liquid crystal phase difference layer, in this order from the adhesive layer side.

Description

[Technical Field]

[0001] This invention relates to an optical laminate. [Background technology]

[0002] Conventionally, OLEDs have used circular polarizers with multiple liquid crystal phase difference layers to prevent external light reflection, and in response to the demand for thinner designs, circular polarizers with a protective layer for the linear polarizer on only one side (the viewing side) are also known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-046029 [Patent Document 2] Japanese Patent Publication No. 2023-068424 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, when a protective layer is applied to only one side of a linear polarizer, exposure to high temperature and high humidity conditions can cause dichroic dyes such as iodine to be lost from the linear polarizer, or unevenness to occur, resulting in insufficient visibility.

[0005] The present invention has been made in view of the above problems, and aims to provide an optical laminate that has a protective layer on only one side of the linear polarizer, while suppressing the disappearance of dichroic dye from the linear polarizer in high temperature and high humidity environments, and suppressing the reduction in visibility due to unevenness. [Means for solving the problem]

[0006] [1] comprising a first protective layer, a linear polarizer, an adhesive layer, and a phase difference layer laminate in this order, The adhesive layer has a storage modulus of 0.2 to 1.0 MPa at 25°C and a thickness of 2 to 25 μm. The phase difference layer laminate is an optical laminate having a first liquid crystal phase difference layer, an adhesive layer having a thickness of 20 to 200 nm, and a second liquid crystal phase difference layer, in this order from the adhesive layer side. [2] The optical laminate according to [1], wherein the parameter X, which is the product of the saturated moisture content (mass%) and thickness (μm) of the adhesive layer at 25°C and 80% relative humidity, is between 3 and 23. [3] The optical laminate according to [1] or [2], wherein the adhesive layer has a thickness of 2 to 15 μm. [4] The optical laminate according to any one of [1] to [3], wherein the adhesive layer has a thickness of 2 to 10 μm. [5] The optical laminate according to any one of [1] to [4], wherein the adhesive layer is a water-based adhesive layer. [6] The optical laminate according to any one of [1] to [5], wherein the adhesive layer has a thickness of 25 to 150 nm. [7] When the in-plane phase difference value of the phase difference layer laminate with respect to light of wavelength λnm is Re(λ), the optical laminate according to any one of the following equations (1) and (2) is satisfied. 80nm ≤ Re(450) ≤ 130nm (1) Re(450) / Re(550)≦1.00 (2) [Effects of the Invention]

[0007] According to the present invention, an optical laminate is provided that can suppress the disappearance of dichroic dye from a linear polarizer and suppress the reduction in visibility due to unevenness. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic cross-sectional view showing one embodiment of a phase difference layer laminate 300 and an optical laminate 400 according to one embodiment. [Modes for carrying out the invention]

[0009] (Optical laminate (circular polarizer) 400) As shown in Figure 1, the optical laminate 400 according to this embodiment comprises a first protective layer 180, a linear polarizer 220, an adhesive layer 150, and a phase difference layer laminate 300 in this order, and can function as a circular polarizer.

[0010] (Linear polarizer 220) A linear polarizer has the function of selectively transmitting linearly polarized light in a certain direction from unpolarized light rays such as natural light. Examples of linear polarizers include films (hereinafter also called "polarizers") that are uniaxially stretched while impregnated with dichroic dyes such as iodine or organic dichroic dyes in a polymer such as PVA, and optically anisotropic layers (hereinafter also called "polarizing films") that are formed by aligning dichroic dyes and polymerizable liquid crystal compounds.

[0011] The polarization performance of a linear polarizer can be measured using a spectrophotometer. For example, the transmittance in the transmission axis direction (perpendicular to orientation) (T1) and the transmittance in the absorption axis direction (orientation direction) (T2) in the visible light wavelength range of 380 nm to 780 nm can be measured using the double-beam method with a spectrophotometer equipped with a prism polarizer. The polarization performance in the visible light range can be calculated by using the following equations (Equation 1) and (Equation 2) to calculate the single transmittance and polarization degree at each wavelength, and then performing luminous efficiency correction using a 2-degree field of view (C light source) as defined in JIS Z 8701 to calculate the luminous efficiency-corrected single transmittance (Ty) and luminous efficiency-corrected polarization degree (Py). Similarly, L can be calculated from the measured transmittance using the color matching function of the C light source. * a * b * Chromaticity a in the (CIE) color system * and b * By calculating this, the hue of a single linear polarizer (single hue), the hue of linear polarizers arranged in parallel (parallel hue), and the hue of linear polarizers arranged orthogonally (orthogonal hue) can be obtained. * and b * The closer the value is to 0, the more neutral the hue is considered to be. Single element transmittance (%) = (T1 + T2) / 2 ... (Equation 1) Polarization degree (%) = (T1-T2) / (T1+T2)×100 ... (Equation 2)

[0012] The luminous efficiency correction polarization degree Py of a linear polarizer is usually 80% or higher, preferably 90% or higher, more preferably 95% or higher, even more preferably 98% or higher, particularly preferably 99% or higher, and may even be 99.9% or higher. Increasing the luminous efficiency correction polarization degree Py of a linear polarizer is advantageous in enhancing the anti-reflective function of the optical laminate. If the luminous efficiency correction polarization degree Py is less than 80%, the anti-reflective function may not be achieved when used as an anti-reflective film.

[0013] The luminous efficiency correction single transmittance Ty of a linear polarizer improves clarity when displaying white as it increases. However, as can be seen from the relationship between (Equation 1) and (Equation 2), there is a problem that the polarization degree decreases if the single transmittance is too high. Therefore, it is preferable that it is between 30% and 60%, more preferably between 35% and 55%, even more preferably between 38% and 50%, even more preferably between 40% and 45%, and most preferably between 41% and 43%. If the luminous efficiency correction single transmittance Ty is excessively high, the luminous efficiency correction polarization degree Py becomes too low, which may result in insufficient anti-reflective function when used as an anti-reflective film.

[0014] <Polarizer> A film produced by uniaxially stretching a polymer such as polyvinyl alcohol resin film (PVA) impregnated with dichroic dyes such as iodine or organic dichroic dyes can typically be manufactured by following these steps: uniaxial stretching of the polyvinyl alcohol resin film; a step of dyeing the polyvinyl alcohol resin film with a dichroic dye such as iodine to adsorb the dichroic dye; a step of treating the polyvinyl alcohol resin film on which the dichroic dye has been adsorbed with a crosslinking agent such as a boric acid aqueous solution; and a step of washing with water after treatment with the crosslinking agent such as a boric acid aqueous solution.

[0015] The thickness of the polarizer is usually 30 μm or less, preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness is usually 1 μm or more, and may be, for example, 5 μm or more.

[0016] Uniaxial stretching of polyvinyl alcohol-based resin films can be performed before, simultaneously with, or after dyeing with dichroic dyes. When uniaxial stretching is performed after dyeing, it may be performed before or during boric acid treatment. Of course, uniaxial stretching can also be performed in multiple stages as shown here. Uniaxial stretching methods include stretching uniaxially in the film transport direction between rolls with different peripheral speeds, stretching uniaxially in the film transport direction using a heated roll, or stretching in the width direction using a tenter. Uniaxial stretching may also be performed by dry stretching in the atmosphere, or by wet stretching using a solvent such as water to swell the polyvinyl alcohol-based resin film before stretching. The stretching ratio is usually around 3 to 8 times. Alternatively, an aqueous solution containing polyvinyl alcohol may be applied to a thermoplastic resin film, followed by a drying treatment, and then stretched together with the thermoplastic resin film using the above method.

[0017] Dyeing of polyvinyl alcohol-based resin films with dichroic dyes can be carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. Specifically, iodine or dichroic organic dyes can be used as dichroic dyes. It is preferable to immerse the polyvinyl alcohol-based resin film in water to swell it before the dyeing treatment.

[0018] When iodine is used as a dichroic dye, a method of dyeing is usually employed in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing iodine and potassium iodide. 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 (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.

[0019] On the other hand, when using a dichroic organic dye as the dichroic pigment, a method is usually employed in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a water-soluble dichroic organic dye. The content of the dichroic organic dye in this aqueous solution is usually about 0.0001 to 10 parts by mass, preferably 0.001 to 1 part by mass, per 100 parts by mass of water. This dye aqueous solution may also contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dichroic organic dye aqueous solution used for dyeing is usually about 20 to 80°C. The immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

[0020] The boric acid treatment after dyeing with a dichroic dye can be carried out by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The boric acid content in the boric acid-containing aqueous solution is usually 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, it is preferable that the boric acid-containing aqueous solution contains potassium iodide. The potassium iodide content in the boric acid-containing aqueous solution is usually 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 usually 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 usually 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

[0021] Polyvinyl alcohol-based resin films treated with boric acid are typically washed with water. This washing can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The water temperature during washing is usually around 5 to 40°C, and the immersion time is usually around 1 to 120 seconds.

[0022] After washing with water, the polarizer is dried to obtain a polarizer. The drying process can be carried out using a hot air dryer or a far-infrared heater. The drying temperature is usually around 30 to 100°C, preferably 50 to 80°C. The drying time is usually around 60 to 600 seconds, preferably 120 to 600 seconds. The drying process reduces the moisture content in the polarizer to a practical level. The moisture content is usually around 5 to 20% by mass of the total mass of the polarizer, preferably 8 to 15% by mass. If the moisture content is 5% by mass or more, the polarizer has sufficient flexibility, thus preventing damage or breakage after drying. If the moisture content is 20% by mass or less, the polarizer has sufficient thermal stability.

[0023] As described above, a polarizer can be manufactured in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film.

[0024] <Polarizing film> A polarizing film, i.e., an optically anisotropic layer made of a polymerizable liquid crystal compound containing a dichroic dye, can be suitably used in flexible display applications, for example, because its hue can be arbitrarily controlled, it can be made significantly thinner, and it is non-shrinkable due to the absence of thermal stretching relaxation.

[0025] A polarizing film is formed by applying a polarizing film-forming composition to an alignment film formed on a substrate as needed, and then orienting the dichroic dye contained in the polarizing film-forming composition. The polarizing film is a film with a thickness of 0.1 μm to 5 μm, more preferably 0.3 μm to 4 μm, and even more preferably 0.5 μm to 3 μm. If the film thickness is thinner than this range, the required light absorption may not be obtained, and if the film thickness is thicker than this range, the orientation-regulating force of the alignment film decreases, and orientation defects tend to occur. The polarizing film-forming composition may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an adhesion improver.

[0026] In an optically anisotropic layer in which a dichroic dye and a polymerizable liquid crystal compound are horizontally oriented with respect to the substrate surface, the ratio (dichroic ratio) of the absorbance A1(λ) in the orientation direction to the absorbance A2(λ) in the direction perpendicular to the orientation plane with respect to light of wavelength λnm is preferably 7 or higher, more preferably 20 or higher, and even more preferably 40 or higher. The higher this value, the better the absorption selectivity of the polarizer. Depending on the type of dichroic dye, in the case of a liquid crystal cured film cured in the nematic liquid crystal phase state, it is about 5 to 10.

[0027] By mixing two or more dichroic dyes with different absorption wavelengths, polarizing films of various hues can be created, resulting in polarizing films that absorb across the entire visible light spectrum. Such polarizing films with specific absorption characteristics can be applied to a wide range of uses.

[0028] <Polarizing film; polymerizable liquid crystal compound> A polymerizable liquid crystal compound is a compound that has polymerizable groups and liquid crystal properties (hereinafter also referred to as polymerizable liquid crystal). A polymerizable group is a group that participates in the polymerization reaction, and it is preferable that it be a photopolymerizable group. Here, a photopolymerizable group is a group that can participate in the polymerization reaction by active radicals or acids generated from a photopolymerization initiator, which will be described later. Examples of polymerizable groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are preferred, and methacryloyloxy groups or acryloyloxy groups are more preferred. The liquid crystal properties may be thermotropic liquid crystal or lyotropic liquid crystal, but when mixed with a dichroic dye, which will be described later, thermotropic liquid crystal is preferred. A polymerizable liquid crystal compound may be a monomer or a polymer obtained by polymerizing dimers or more.

[0029] When the polymerizable liquid crystal compound is a thermotropic liquid crystal, it may be a thermotropic liquid crystal compound exhibiting a nematic liquid crystal phase, or a thermotropic liquid crystal compound exhibiting a smectic liquid crystal phase. From the viewpoint of being able to exhibit high dichroism, the liquid crystal state exhibited by the polymerizable liquid crystal compound is preferably a smectic phase, and from the viewpoint of performance improvement, a higher-order smectic phase is more preferable. Among these, higher-order smectic liquid crystal compounds that form smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase, or smectic L phase are more preferable, and higher-order smectic liquid crystal compounds that form smectic B phase, smectic F phase, or smectic I phase are even more preferable. When the liquid crystal phase formed by the polymerizable liquid crystal is one of these higher-order smectic phases, a polarizing film with higher polarization performance can be manufactured. Furthermore, polarizing films with such high polarization performance yield Bragg peaks originating from higher-order structures such as the hexatic phase and crystalline phase in X-ray diffraction measurements. These Bragg peaks originate from the periodic structure of molecular orientation, and films with a periodic interval of 3 to 6 Å can be obtained. From the viewpoint of obtaining even higher polarization characteristics, it is preferable that the polarizing film of the present invention contains a polymer of polymerizable liquid crystal in which the polymerizable liquid crystal is oriented in the smectic phase.

[0030] As the polymerizable liquid crystal compound, one type may be used alone, or two or more types may be used in combination. The polymerizable liquid crystal composition containing other compounds, as described later, may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound, as long as the effects of the present invention are not impaired. However, from the viewpoint of obtaining a polarizing film with a high degree of orientation order, the ratio of the polymerizable liquid crystal compound to the total mass of all polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0031] The polymerizable liquid crystal compound content in the polarizing film-forming composition of the present invention is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and even more preferably 70 to 99% by mass, relative to the solid content of the polymerizable liquid crystal composition. When the polymerizable liquid crystal compound content is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In this specification, solid content refers to the total amount of components excluding the solvent from the polymerizable liquid crystal composition.

[0032] <Polarizing film; dichroic dye> Dichroic dyes are dyes that have different absorbances along the long axis and short axis of the molecule. Dichroic dyes preferably have the property of absorbing visible light, and more preferably have an absorption maximum wavelength (λMAX) in the range of 380 to 680 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, with azo dyes being preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbenazo dyes, with bisazo dyes and trisazo dyes being preferred. Dichroic dyes may be used individually or in combination, but to obtain absorption across the entire visible light range, it is preferable to combine two or more dichroic dyes, and more preferably to combine three or more dichroic dyes.

[0033] Examples of azo dyes include the compound represented by formula (I) (hereinafter sometimes referred to as "compound (I)"). T1-A1(-N=N-A2)pN=N-A3-T2(I) [In formula (I), A1, A2, and A3 independently represent an optionally substituted 1,4-phenylene group, an optionally substituted naphthalene-1,4-diyl group, an optionally substituted phenyl benzoate group, an optionally substituted 4,4'-stilbenylene group, or an optionally substituted divalent heterocyclic group, where T1 and T2 are electron-withdrawing or electron-emitting groups located substantially 180° to the azo bond plane. p represents an integer from 0 to 4. When p is 2 or greater, each A2 may be identical or different from the others. The -N=N- bond may be replaced by -C=C-, -COO-, -NHCO-, or -N=CH- bond in the range showing absorption in the visible region.]

[0034] The content of dichroic dyes (total amount if multiple types are included) is typically 1 to 60 parts by mass, preferably 1 to 40 parts by mass, and more preferably 1 to 20 parts by mass, per 100 parts by mass of polymerizable liquid crystal compound, from the viewpoint of obtaining good light absorption characteristics. If the content of dichroic dyes is less than this range, light absorption will be insufficient and sufficient polarization performance cannot be obtained, and if it is more than this range, it may inhibit the orientation of liquid crystal molecules.

[0035] (1st protective layer 180) The first protective layer 180 has the function of protecting the visible surface of the linear polarizer 220, which is opposite to the phase difference layer laminate 300. The first protective layer 180 is laminated onto the linear polarizer 220 via an adhesive layer or bonding agent layer as needed. Alternatively, the first protective layer 180 may be directly laminated to the linear polarizer 220. Here, "directly laminated" includes a configuration in which the first protective layer is laminated to the linear polarizer by its self-adhesion. To improve adhesion with the linear polarizer, the first protective layer may be surface-treated (e.g., corona treatment, etc.), and a thin layer such as a primer layer (also called an easy-adhesion layer) may be formed on it. There are no particular limitations on the materials of the adhesive layer and tack layer that may be interposed between the first protective layer 180 and the linear polarizer 220. Examples of adhesives include cured products of curable compositions containing cationic polymerizable compounds and / or radical polymerizable compounds, and water-based adhesives as described in detail in the section on adhesive layer 40. Examples of tacks include acrylic tacks, urethane tacks, and silicone tacks.

[0036] As the first protective layer, for example, a resin film with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and stretchability can be used. The resin film may also be a thermoplastic resin film. Specific examples of such resins include cellulosic resins such as triacetylcellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins having cyclo and norbornene structures (also called norbornene resins); (meth)acrylic resins such as polymethyl methacrylate; polyarylate resins; polystyrene resins; polyvinyl alcohol resins; and mixtures thereof. Protective films of such materials are readily available on the market. In this specification, (meth)acrylic means either acrylic or methacrylic.

[0037] The thickness of the thermoplastic resin film is preferably 0.1 μm to 60 μm, more preferably 0.5 μm to 50 μm, and even more preferably 1 μm to 40 μm.

[0038] The thermoplastic resin film may be subjected to surface treatments such as hard coating, anti-reflective coating, anti-sticking coating, and anti-glare coating, as needed. Furthermore, the thermoplastic resin film may be subjected to treatments to improve visibility when viewed through polarized sunglasses (typically, by providing (elliptical) polarization functionality or providing ultra-high phase difference), as needed. By applying such treatments, excellent visibility can be achieved even when viewing the display screen through polarized lenses such as polarized sunglasses. Therefore, polarizing plates with a phase difference layer can be suitably applied to image display devices that may be used outdoors.

[0039] A thermoplastic resin film can be produced by stretching a film containing the above-mentioned thermoplastic resin. Stretching methods include uniaxial stretching and biaxial stretching. Stretching directions include the machine flow direction (MD) of the unstretched film, a direction perpendicular to it (TD), and a direction oblique to the machine flow direction (MD). Biaxial stretching may be simultaneous biaxial stretching, where the film is stretched in two directions simultaneously, or sequential biaxial stretching, where the film is stretched in one direction first, and then in another. Stretching can be performed, for example, by using two or more nip rolls with a high peripheral speed on the exit side to stretch the film longitudinally (machine flow direction: MD), or by gripping both ends of the unstretched film with chucks and spreading it in a direction perpendicular to the machine flow direction (TD). In this process, the phase difference value and wavelength dispersion can be controlled by adjusting the film thickness or the stretching ratio. Furthermore, the wavelength dispersion value can be controlled by adding a wavelength dispersion modifier to the resin.

[0040] The above thermoplastic resin film may contain any suitable additives depending on the purpose. Examples of additives include: antioxidants such as hindered phenol, phosphorus, and sulfur-based antioxidants; stabilizers such as light stabilizers, ultraviolet absorbers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; near-infrared absorbers; flame retardants such as tris(dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic and inorganic fillers; resin modifiers; plasticizers; lubricants; and phase difference reducing agents. The types, combinations, and amounts of additives contained can be appropriately set according to the purpose and desired properties.

[0041] Furthermore, a coating layer (surface treatment layer) can be provided on the outer surface of the thermoplastic resin film to impart desired surface optical properties or other characteristics. Specific examples of surface treatment layers include hard coat layers, anti-glare layers, anti-reflective layers, anti-static layers, and anti-fouling layers. The method for forming the surface treatment layer is not particularly limited, and known methods can be used. The surface treatment layer may be formed on one side of the thermoplastic resin film or on both sides.

[0042] [Hard coat layer] The hard coat layer has the function of increasing the surface hardness of the thermoplastic resin film and is provided for purposes such as preventing surface scratches. Preferably, the hard coat layer has a pencil hardness of H or a harder value as measured by the pencil hardness test specified in JIS K 5600-5-4:1999 "General test methods for paints - Part 5: Mechanical properties of coatings - Section 4: Scratch hardness (pencil method)" (measured by placing an optical film with a hard coat layer on a glass plate).

[0043] The materials used to form the hard coat layer generally harden with heat or light. Examples include organic hard coat materials such as organic silicones, melamines, epoxys, (meth)acrylics, and urethane (meth)acrylates, and inorganic hard coat materials such as silicon dioxide. Among these, urethane (meth)acrylate or polyfunctional (meth)acrylate hard coat materials are preferred because they have good adhesion to thermoplastic resin films and excellent productivity. In this specification, (meth)acrylate means either acrylate or methacrylate.

[0044] The hard coat layer may contain various fillers as desired, for the purpose of adjusting the refractive index, improving the flexural modulus, stabilizing the volume shrinkage rate, and further improving heat resistance, antistatic properties, anti-glare properties, etc. The hard coat layer may also contain additives such as antioxidants, UV absorbers, light stabilizers, antistatic agents, leveling agents, and defoamers.

[0045] The hard coat layer may contain additives to further improve its strength. The additives are not limited to inorganic fine particles, organic fine particles, or mixtures thereof. While a thicker hard coat layer is preferable for hardness, if it is too thick, it becomes prone to cracking when cut, so it may be 1 μm to 20 μm or 2 μm to 10 μm. The thickness of the hard coat layer is preferably 3 μm to 7 μm.

[0046] The anti-glare layer is a layer having a fine uneven surface, and is preferably formed using the hard coat material described above.

[0047] An anti-glare layer having a fine uneven surface can be formed by: 1) forming a coating film containing fine particles on a stretched film to create an uneven surface based on those fine particles; or 2) forming a coating film containing or not containing fine particles on a stretched film, and then pressing it against a mold (such as a roll) with an uneven surface to transfer the uneven shape (also known as the embossing method).

[0048] An anti-reflective layer is a layer that reduces the reflection of ambient light from the surface of a thermoplastic resin film for those observing the film, and typically has a reflectivity of 1.5% or less for visible light. Such an anti-reflective layer is typically formed by laminating a high refractive index layer with a high refractive index and a low refractive index layer with a low refractive index, or by using the method or materials described in Japanese Patent Application Publication No. 2021-6929. By adjusting the refractive indices and the thickness of each layer, the reflected light from each layer can be weakened by each other, resulting in an excellent anti-reflective function.

[0049] As will be described in detail later, it is preferable to manufacture an anti-reflective layer consisting of a high refractive index layer and a low refractive index layer using a coating composition capable of forming both the high refractive index layer and the low refractive index layer, as this process is extremely simple. Here is an example of a coating composition capable of forming both the high refractive index layer and the low refractive index layer. Such a coating composition is liquid and contains a suitable curable resin and, if necessary, additives. A coating composition capable of forming a high refractive index layer (a composition for forming a high refractive index layer) is, for example, obtained by dissolving a curable resin such as urethane acrylate and a photopolymerization initiator (photopolymerization initiator) such as acetophenone, benzophenone, benzyldimethylketal, α-hydroxyalkylphenone, α-aminoalkylphenone, or thioxanthone in a solvent such as methyl ethyl ketone or methyl isobutyl ketone. To improve coatability, a leveling agent, preferably a fluorine-based leveling agent, may be included. Furthermore, as a coating-type composition capable of forming a low refractive index layer (composition for forming a low refractive index layer), silica particles are dispersed in a solution obtained by dissolving a photopolymerization initiator (photopolymerization initiator) such as acetophenone-based, benzophenone-based, benzyldimethylketal-based, α-hydroxyalkylphenone-based, α-aminoalkylphenone-based, or thioxanthone-based in a solvent such as 1-methoxy-2-propyl acetate or methyl isobutyl in a binder resin such as polyethylene glycol diacrylate or pentaerythritol (tri / tetra)acrylate as a curable resin. To further improve coatability, a fluorine-based leveling agent may be included. Note that the coating-type compositions capable of forming high refractive index layers and low refractive index layers listed here are merely examples, and it is preferable to optimize the high refractive index layer-forming composition and the low refractive index layer-forming composition, respectively, according to the characteristics of the anti-reflective layer to be formed.

[0050] The anti-reflective layer may, for example, include a low refractive index layer. Alternatively, it may be a multilayer structure further comprising a high refractive index layer and / or a medium refractive index layer between the thermoplastic resin film and the low refractive index layer.

[0051] A low refractive index layer can be formed by applying a coating solution containing a light-transmitting resin such as a cured product of the aforementioned curable resin or a metal alkoxide polymer, and inorganic particles, and then curing the coating layer as needed. Examples of inorganic particles include low refractive index particles such as LiF (refractive index 1.4), MgF (refractive index 1.4), 3NaF·AlF (refractive index 1.4), AlF (refractive index 1.4), and Na3AlF6 (refractive index 1.33), as well as hollow silica particles.

[0052] An antistatic layer is provided on the surface of a thermoplastic resin film to impart conductivity and suppress the effects of static electricity. For example, to form the antistatic layer, a method can be employed in which a resin composition containing a conductive substance (antistatic agent) is applied to the thermoplastic resin film. For instance, by including an antistatic agent in the hard coat material used to form the hard coat layer described above, an antistatic hard coat layer can be formed.

[0053] The antifouling layer is provided to impart water repellency, oil repellency, sweat resistance, and antifouling properties. A suitable material for forming the antifouling layer is a fluorine-containing organic compound. Examples of fluorine-containing organic compounds include fluorocarbons, perfluorosilanes, and polymer compounds thereof. Depending on the material to be formed, methods such as physical vapor deposition (typically vapor deposition and sputtering), chemical vapor deposition, and wet coating can be used for forming the antifouling layer. The average thickness of the antifouling layer is usually about 1 to 50 nm, preferably 3 to 35 nm.

[0054] If the first protective layer is a thermoplastic resin layer or a resin layer such as the cured resin layer described later, the linear polarizer and the first protective layer may be in direct contact without an adhesive layer or bonding agent in between.

[0055] For example, a thermoplastic resin layer as a first protective layer can be laminated onto a linear polarizer by applying a composition containing a thermoplastic resin onto a support substrate, drying it as necessary, and bonding the resulting thermoplastic resin layer with the support substrate to a linear polarizer via an adhesive layer or bonding agent as necessary, and then peeling off the support substrate (first method). For example, if the first protective layer is a thermoplastic resin layer, it is also possible to form the thermoplastic resin layer by directly applying the above composition to the surface of the linear polarizer and drying it as necessary. In this case, the linear polarizer and the first protective layer are in direct contact without an adhesive layer or bonding agent (second method). However, if the composition contains a solvent, the first method is preferred because it is easier to stably form a thermoplastic resin layer with a sufficiently reduced solvent content.

[0056] The first protective layer may be a cured resin layer containing a cured product of a curable resin. Examples of curable resins include thermosetting resins and active energy curing resins, such as (meth)acrylic resins, epoxy resins, oxetane resins, urethane resins, (meth)acrylic urethane resins, and melamine resins. A cured resin layer containing a cured product of a curable resin can be formed by applying a composition containing a curable resin onto a support substrate, drying it as necessary, and then applying heat or irradiating it with active energy rays such as visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams. The resulting cured resin layer with a support substrate can be laminated onto a linear polarizer as the first protective layer by bonding the support substrate to a linear polarizer via an adhesive layer as necessary, and then peeling off the support substrate.

[0057] (Adhesive layer 150) The adhesive layer 150 bonds the linear polarizer 220 to the first liquid crystal phase difference layer 30. The adhesive is also called a pressure-sensitive adhesive. The adhesive layer 150 is in direct contact with the linear polarizer 220, or, if the linear polarizer 220 has an alignment film on the side facing the first liquid crystal phase difference layer 30, it is in direct contact with the alignment film of the linear polarizer 220. Therefore, no layer such as the thermoplastic resin film exemplified in the section on the first protective layer 180 is interposed between the linear polarizer 220 and the first liquid crystal phase difference layer 30.

[0058] The adhesive layer 150 is in direct contact with the first liquid crystal phase difference layer 30, or, if the first liquid crystal phase difference layer 30 has an alignment film on the side facing the linear polarizer 220, it is in direct contact with the alignment film of the first liquid crystal phase difference layer 30. Therefore, no layer such as the thermoplastic resin film exemplified in the section on the first protective layer 180 is interposed between the adhesive layer 150 and the first liquid crystal phase difference layer 30.

[0059] The thickness of the adhesive layer 150 is 2 to 25 μm, and may be 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less. From the viewpoint of suppressing the disappearance of dichroic dyes such as iodine from the linear polarizer due to water contained in the adhesive layer, a smaller thickness of the adhesive layer 150 is preferable. Also, from the viewpoint of adhesion, a thickness of 3 μm or more of the adhesive layer 150 is preferable.

[0060] The adhesive layer 150 has a storage modulus of 0.2 to 1.0 MPa at 25°C. The storage modulus may be 0.9 MPa or less, 0.8 MPa or less, 0.7 MPa or less, 0.3 MPa or more, 0.4 MPa or more, or 0.5 MPa or more. The storage modulus can be adjusted by the type and amount of crosslinking agent in the adhesive layer forming composition described later. If the storage modulus is too high, it tends to crack easily when bent.

[0061] (Adhesive layer parameter X) Parameter X, which is the product of the saturated moisture content (mass%) and thickness (μm) of the adhesive layer 150 at 25°C and 80% relative humidity, is preferably 3 to 23, and more preferably 3 to 18. Parameter X is an indicator of the amount of water contained in the adhesive layer. Since water tends to promote the movement of dichroic dyes such as iodine within the linear polarizer, satisfying the above range for parameter X makes it easier to further reduce the loss of dichroic dyes such as iodine from the linear polarizer. Parameter X may be 15 or less, 12 or less, 10 or less, or 7 or less. If parameter X is too large, there is too much moisture, which tends to lead to greater iodine loss. If the parameter is too small, the adhesive becomes hard due to a high crosslinking density when the saturated moisture content is low, and when it becomes thin, the adhesive itself is more prone to fracture, which tends to prevent sufficient adhesion. Detailed methods for measuring the saturated moisture content will be described later. The typical saturated moisture content (mass%) of an adhesive layer at 25°C and 80% relative humidity is 0.2 to 1.5 mass%. The saturated moisture content of the adhesive layer can be adjusted by the amount and type of crosslinking components.

[0062] As the adhesive layer forming composition for forming such an adhesive layer, any conventionally known adhesive layer forming composition with excellent optical transparency can be used without particular limitation. For example, an adhesive layer forming composition having a base polymer such as an acrylic resin, urethane resin, silicone resin, or polyvinyl ether resin can be used. Alternatively, an active energy ray curable adhesive layer forming composition or a thermosetting adhesive layer forming composition may also be used. Among these, an adhesive layer forming composition using an acrylic resin as the base polymer, which has excellent transparency, adhesive strength, re-peelability, weather resistance, and heat resistance, is preferred.

[0063] The adhesive layer-forming composition may further contain a crosslinking agent, a silane compound, an antistatic agent, and the like.

[0064] [(meth)acrylic resin] The (meth)acrylic resin contained in the composition for forming the adhesive layer is preferably a polymer having a structural unit derived from an alkyl (meth)acrylate represented by the following formula (I) (hereinafter also referred to as "structural unit (I)") as a main component (for example, contained in an amount of 50 parts by mass or more based on 100 parts by mass of the structural units of the (meth)acrylic resin) (hereinafter also referred to as "(meth)acrylate polymer").

[0065] In this specification, the (meth)acrylic resin means either an acrylic resin or a methacrylic resin, and "(meth)" such as (meth)acrylate also has the same meaning. [Chemical formula] [In the formula, R 10 represents a hydrogen atom or a methyl group, and R 20 represents an alkyl group having 1 to 20 carbon atoms. The alkyl group may have any of a linear, branched or cyclic structure, and the hydrogen atom of the alkyl group may be replaced by an alkoxy group having 1 to 10 carbon atoms.]

[0066] Examples of (meth)acrylic acid esters represented by formula (I) 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 include octyl (meth)acrylate, i-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n- and i-nonyl (meth)acrylate, n-decyl (meth)acrylate, i-decyl (meth)acrylate, n-dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobolonyl (meth)acrylate, stearyl (meth)acrylate, and t-butyl (meth)acrylate. Specific examples of alkoxy group-containing alkyl acrylates include 2-methoxyethyl (meth)acrylate and ethoxymethyl (meth)acrylate. Among these, it is preferable to include n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, and particularly preferable to include n-butyl (meth)acrylate.

[0067] (Meth)acrylic acid ester polymers may contain structural units derived from monomers other than structural unit (I). The structural units derived from other monomers may be one type or two or more types. Other monomers that (meth)acrylic acid ester polymers may contain include monomers having polar functional groups, monomers having aromatic groups, and acrylamide monomers.

[0068] Examples of monomers having polar functional groups include (meth)acrylates having polar functional groups. Examples of polar functional groups include hydroxyl groups, carboxyl groups, substituted amino groups or unsubstituted amino groups substituted with alkyl groups having 1 to 6 carbon atoms, and heterocyclic groups such as epoxy groups.

[0069] The content of structural units derived from monomers having polar functional groups 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, per 100 parts by mass of the total structural units of the (meth)acrylic acid ester polymer.

[0070] Examples of monomers containing aromatic groups include (meth)acrylic acid esters that have one (meth)acryloyl group and one or more aromatic rings (e.g., a benzene ring, a naphthalene ring, etc.) in the molecule, and that contain a phenyl group, a phenoxyethyl group, or a benzyl group. By including these structural units, it is possible to suppress the whitening phenomenon of polarizing plates that occurs in high temperature and high humidity environments.

[0071] The content of structural units derived from monomers having aromatic groups in the (meth)acrylic acid 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, per 100 parts by mass of the total structural units of the (meth)acrylic acid polymer.

[0072] Examples of acrylamide monomers include N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, and N-(2-methylpropoxymethyl)acrylamide. By including these structural units, the bleed-out of additives such as antistatic agents, which will be discussed later, can be suppressed.

[0073] Furthermore, structural units derived from monomers other than structural unit (I) may include structural units derived from styrene monomers, structural units derived from vinyl monomers, structural units derived from monomers having multiple (meth)acryloyl groups in the molecule, and so on.

[0074] 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. If the weight-average molecular weight is 500,000 or more, the durability of the adhesive layer in high-temperature, high-humidity environments can be improved. If the weight-average molecular weight is 2,500,000 or less, the operability when applying the coating liquid containing the adhesive layer forming composition is improved. 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).

[0075] The (meth)acrylic resin, when dissolved in ethyl acetate to form a 20% by mass solution, preferably has a viscosity of 20 Pa·s or less at 25°C, and more preferably between 0.1 and 15 Pa·s. When the viscosity of the (meth)acrylic resin at 25°C is within the above range, it contributes to improved durability and reworkability of the polarizing plate containing the adhesive layer formed by the resin. The viscosity can be measured using a Brookfield viscometer.

[0076] The glass transition temperature (Tg) of (meth)acrylic resins 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 differential scanning calorimeter (DSC).

[0077] (Meth)acrylic resins may contain two or more (meth)acrylic acid ester polymers. Examples of such (meth)acrylic acid ester polymers include relatively low molecular weight (meth)acrylic acid ester polymers whose main component is structural unit (I) derived from the (meth)acrylic acid ester, and whose weight-average molecular weight is in the range of 50,000 to 300,000.

[0078] (Meth)acrylic resins can usually be produced by known polymerization methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. In the production of (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 amount of all monomers constituting the (meth)acrylic resin. (Meth)acrylic resins can also be produced by polymerization using active energy rays such as ultraviolet light.

[0079] [Crosslinking agent] The adhesive layer-forming composition preferably contains a crosslinking agent. Examples of crosslinking agents 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 viewpoint of the pot life of the adhesive layer-forming composition, the crosslinking rate, and the durability of the polarizing plate.

[0080] Isocyanate compounds are compounds having at least two isocyanate groups (-NCO) in their molecule. Specifically, examples include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. Adduct compounds obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolprone, as well as dimers and trimers of these isocyanate compounds, are also examples. Two or more isocyanate compounds may be combined.

[0081] The proportion of the crosslinking agent 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, per 100 parts by mass of (meth)acrylic resin.

[0082] [Silane compounds] The adhesive layer-forming composition may further contain a silane compound.

[0083] Examples of silane compounds 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.

[0084] Furthermore, the silane compound may contain oligomers derived from the above-mentioned silane compound.

[0085] The silane compound content in the adhesive layer-forming composition is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, per 100 parts by mass of (meth)acrylic resin. When the silane compound content is 0.01 parts by mass or more, the adhesion between the adhesive layer and the adherend tends to improve, and when the content is 10 parts by mass or less, the bleed-out of the silane compound from the adhesive layer tends to be suppressed. A silane coupling agent is suitable as the silane compound, and known silane coupling agents can be used.

[0086] <Antistatic agent> The adhesive layer-forming composition may further contain an antistatic agent. Known antistatic agents are examples, with ionic antistatic agents being preferred. Examples of cationic components constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of organic cations include pyridinium cations, imidazolium cations, ammonium cations, sulfonium cations, and phosphonium cations. Examples of inorganic cations include alkali metal cations such as lithium cations, potassium cations, sodium cations, and cesium cations, and alkaline earth metal cations such as magnesium cations and calcium cations. The anionic component constituting the ionic antistatic agent may be either an inorganic anion or an organic anion, but an anionic component containing a fluorine atom is preferred due to its superior antistatic performance. An example of an anionic component containing a fluorine atom is the hexafluorophosphate anion (PF6). - ), bis(trifluoromethanesulfonyl)imide anion [(CF3SO2)2N - ], bis(fluorosulfonyl)imide anion [(FSO2)2N - Examples include anions.

[0087] Ionic antistatic agents that are solid at room temperature are preferred because they offer excellent long-term stability of the antistatic performance of the adhesive layer-forming composition.

[0088] The amount of 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, per 100 parts by mass of (meth)acrylic resin.

[0089] The adhesive layer-forming composition may contain one or more additives such as UV absorbers, solvents, crosslinking catalysts, tackifiers, and plasticizers. Furthermore, it is also useful to incorporate UV-curable compounds into the adhesive layer-forming composition, and then cure the formed adhesive layer by irradiating it with UV light to obtain a harder adhesive layer.

[0090] The adhesive layer can be formed, for example, by dissolving or dispersing the adhesive layer-forming composition in a solvent to obtain a solvent-containing adhesive layer-forming composition, and then applying this to the surface of the layer on which the adhesive layer is to be provided and drying it.

[0091] (Phase difference layered laminate 300) The phase difference layer laminate 300 has, in order from the linear polarizer 220 side, a first liquid crystal phase difference layer 30, an adhesive layer 40, and a second liquid crystal phase difference layer 50.

[0092] (First liquid crystal phase difference layer 30 and second liquid crystal phase difference layer 50) The liquid crystal phase difference layer is a cured layer of oriented polymerizable liquid crystal compounds, which exhibits a phase difference.

[0093] The liquid crystal phase difference layer is not limited to any layer that generates a phase difference in any direction. It may be a phase difference layer that generates a phase difference in the plane, such as a positive A plate and a negative A plate, or a layer that generates a phase difference in the thickness direction, such as a positive C plate and a negative C plate. Furthermore, the positive A and negative A plates may each be λ / 4 plates or λ / 2 plates. In addition, the liquid crystal phase difference layer may be tilt-oriented or form a cholesteric-oriented state.

[0094] The first liquid crystal phase difference layer 30 and the second liquid crystal phase difference layer 50 may each be a single-layer liquid crystal phase difference layer or a laminate of multiple liquid crystal phase difference layers. Preferably, the angle θ between the slow phase axis of the first liquid crystal phase difference layer 30 and the transmission axis of the linear polarizer 220 is 10° to 20° or -10° to -20°. This has the effect of effectively suppressing the reflection of ambient light by the metal electrodes when the optical laminate is used in an OLED display device.

[0095] Each liquid crystal phase difference layer may be positive wavelength dispersive or negative wavelength dispersive.

[0096] When the in-plane phase difference value of the phase difference layer laminate 300 with respect to light of wavelength λnm is Re(λ), it is preferable that the following relationships (1) and (2) are satisfied. 80nm ≤ Re(450) ≤ 130nm (1) Re(450) / Re(550)≦1.00 (2) [In equations (1) and (2), Re(450) represents the in-plane phase difference value in nm for light with a wavelength of 450 nm. Re(550) represents the in-plane phase difference value in nm for light with a wavelength of 550 nm.

[0097] In this invention, the in-plane phase difference value of the phase difference layer laminate 300 is measured as a value measured in the state of the optical laminate 400. If the first protective layer 180 included in the optical laminate 400 has a phase difference, it is necessary to cancel out that phase difference value and measure the value in the optical laminate 400 to obtain the in-plane phase difference value of the phase difference layer laminate 300. The above in-plane phase difference value can be measured using an in-plane phase difference measuring device such as the KOBRA-WR manufactured by Oji Instruments Co., Ltd.

[0098] A liquid crystal phase difference layer is typically formed by applying a liquid crystal phase difference layer-forming composition containing a polymerizable liquid crystal compound onto an alignment film formed on a substrate, and then polymerizing and curing the polymerizable liquid crystal compound in an oriented state.

[0099] The thickness of the liquid crystal phase difference layer is typically 10 μm or less, preferably 5 μm or less, and more preferably 0.3 μm to 3 μm.

[0100] To achieve a high level of anti-reflective properties, it is preferable that the liquid crystal phase difference layer has a λ / 4 plate function (i.e., a π / 2 phase difference function) across the entire visible light spectrum. Specifically, an inverse wavelength-dispersive λ / 4 layer is preferred, or a combination of two or more liquid crystal phase difference layers with different orientations is preferred. For example, a combination of a liquid crystal phase difference layer having a λ / 2 plate function (i.e., a π phase difference function) and a liquid crystal phase difference layer having a λ / 4 plate function (i.e., a π / 2 phase difference function) may be used.

[0101] Furthermore, from the viewpoint of compensating for the anti-reflective function in oblique directions, it is preferable to include a layer having anisotropy in the thickness direction (positive C plate). In addition, each liquid crystal phase difference layer may have an optical anisotropy layer that is tilt-oriented or may form a cholesteric-oriented state.

[0102] (Combination of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer) The first and second liquid crystal phase difference layers may be the same liquid crystal phase difference layer, or they may be different types of combinations.

[0103] For example, one of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer may be an inverse wavelength dispersion λ / 4 plate, and the other of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer may be a positive C plate.

[0104] Furthermore, one of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer may be a positive wavelength dispersive λ / 2 plate, and the other of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer may be a positive wavelength dispersive λ / 4 plate.

[0105] Below, we will describe, as an example of a liquid crystal phase difference layer, a laminate of inverse wavelength dispersion λ / 4 plate, positive wavelength dispersion λ / 4 plate, and positive wavelength dispersion λ / 2 plate, as well as a positive C plate.

[0106] (Reverse wavelength dispersion λ / 4 plate (R)) The inverse wavelength dispersion λ / 4 plate preferably satisfies the optical properties shown in the following equations (R1) and (R2), where Re(λ) is the in-plane phase difference with respect to light of wavelength λnm across the entire visible light spectrum, and it is preferable that it satisfies the optical properties shown in the following equations (R1), (R2), and (R3).

[0107] 100nm <Re(550)<160nm …(R1) (In the formula, Re(550) represents the in-plane phase difference value (in-plane retardation) for light with a wavelength of 550 nm.) Re(450) / Re(550)≦1.0 …(R2) 1.00≦Re(650) / Re(550) …(R3) (In the formula, Re(450) represents the in-plane phase difference value (in nm) for light with a wavelength of 450 nm, Re(550) represents the in-plane phase difference value (in nm) for light with a wavelength of 550 nm, and Re(650) represents the in-plane phase difference value (in nm) for light with a wavelength of 650 nm.) When the "Re(450) / Re(550)" ratio of the liquid crystal phase difference layer exceeds 1.0, the light loss on the short-wavelength side increases in the elliptic polarizer equipped with the liquid crystal phase difference layer. Preferably, it is 0.7 to 1.0, more preferably 0.80 to 0.95, even more preferably 0.80 to 0.92, and particularly preferably 0.82 to 0.88.

[0108] The "Re(450) / Re(550)" value can be arbitrarily adjusted by adjusting the mixing ratio of polymerizable liquid crystal compounds, as well as the stacking angles and phase difference values ​​of multiple optical anisotropic layers.

[0109] The in-plane phase difference value of the liquid crystal phase difference layer can be adjusted by the thickness of the liquid crystal phase difference layer. Since the in-plane phase difference value is determined by the following formula (4), to obtain a desired in-plane phase difference value (Re(λ)), it is necessary to adjust Δn(λ) and the film thickness d. The thickness of the liquid crystal phase difference layer is preferably 0.5 μm to 5 μm, and more preferably 1 μm to 3 μm. The thickness of the liquid crystal phase difference layer can be measured by an interferometer, laser microscope, or stylus-type film thickness gauge. Note that Δn(λ) depends on the molecular structure of the polymerizable liquid crystal compound, which will be described later.

[0110] Re(λ) = d × Δn(λ) …(4) (In the formula, Re(λ) represents the in-plane phase difference value (nm) at wavelength λnm, d represents the film thickness, and Δn(λ) represents the birefringence at wavelength λnm.)

[0111] A liquid crystal phase difference layer is typically formed by applying a liquid crystal phase difference layer forming composition to an alignment film formed on a substrate, and polymerizing the polymerizable liquid crystal compounds contained in the liquid crystal phase difference layer composition in an oriented state. The liquid crystal phase difference layer forming composition may further contain a solvent, a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an adhesion improver.

[0112] <Polymerizable liquid crystal compound for forming inverse wavelength dispersion λ / 4 plates> Polymerizable liquid crystal compounds refer to liquid crystal compounds having polymerizable groups, particularly photopolymerizable groups. Conventionally known polymerizable liquid crystal compounds can be used as polymerizable liquid crystal compounds for forming inverse wavelength dispersion λ / 4 plates. A photopolymerizable group is a group that can participate in the polymerization reaction by reaction-active species generated from a photopolymerization initiator, such as active radicals or acids. Examples of photopolymerizable groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are preferred, with acryloyloxy groups being more preferred. The liquid crystal properties can be either thermotropic or lyotropic, but thermotropic liquid crystals are preferred because they allow for precise control of film thickness. Furthermore, the phase order structure in thermotropic liquid crystals can be either nematic or smectic. Furthermore, the liquid crystal may be in the form of a rod or a disc. The polymerizable liquid crystal compound can be used alone or in combination of two or more types.

[0113] As polymerizable liquid crystal compounds, liquid crystals having a T-shaped or H-shaped mesogenic structure with further birefringence in the direction perpendicular to the long axis of the molecule are preferred from the viewpoint of exhibiting inverse wavelength dispersion, and T-shaped liquid crystals are more preferred from the viewpoint of obtaining stronger dispersion. Specifically, the structure of a T-shaped liquid crystal is, for example, the following formula (I):

[0114] [ka] Examples of compounds represented by [the formula shown] are given.

[0115] In formula (I), Ar represents a divalent aromatic group which may have substituents. Preferably, the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, or a sulfur atom. If the divalent group Ar contains two or more aromatic groups, the two or more aromatic groups may be linked to each other by single bonds, divalent bonding groups such as -CO-O-, and -O-.

[0116] G 1 and G 2 Each of these independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atoms contained in the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with halogen atoms, C1-C4 alkyl groups, C1-C4 fluoroalkyl groups, C1-C4 alkoxy groups, cyano groups, or nitro groups, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with oxygen atoms, sulfur atoms, or nitrogen atoms.

[0117] L 1 , L 2 、 B 1 and B 2 Each of these is independently a single bond or a divalent linking group.

[0118] k and l each represent integers from 0 to 3 independently, satisfying the relationship 1 ≤ k + l. Here, if 2 ≤ k + l, then B 1 and B 2 , G 1 and G 2 These elements may be identical to each other, or they may be different.

[0119] E 1 and E 2Each of these independently represents an alkanediyl group having 1 to 17 carbon atoms, where the hydrogen atoms in the alkanediyl group may be substituted with halogen atoms, and the -CH2- groups in the alkanediyl group may be substituted with -O-, -S-, or -COO-, and if there are multiple -O-, -S-, or -COO- groups, they are not adjacent to each other. 1 and P 2 Each of these independently represents a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

[0120] G 1 and G 2 Each of these is 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 methyl-substituted 1,4-phenylenediyl 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-cyclohexandiyl group.

[0121] Also, there are multiple G 1 and G 2 Preferably, at least one of them is a divalent alicyclic hydrocarbon group, and L 1 or L 2 G that joins 1 and G 2 It is more preferable that at least one of these is a divalent alicyclic hydrocarbon group.

[0122] L 1 and L 2 Each of these is independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 Ure a2 -, -R a3 COOR a4 -, -R a5 OCOR a6 -, -Ra7 OC=OOR a8 -, -N=N-, -CR c =CR d -, or -C≡C-. Here, R a1 ~R a8 Each of these independently represents a single bond or an alkylene group with 1 to 4 carbon atoms, R c and R d L represents an alkyl group with 1 to 4 carbon atoms or a hydrogen atom. 1 and L 2 Each is independently, more preferably a single bond, -OR a2-1 -, -CH2-, -CH2CH2-, -COOR a4-1 -, or -OCOR a6-1 - is the case here R a2-1 , R a4-1 , R a6-1 Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and L 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, or -OCO-.

[0123] B 1 and B 2 Each of these is independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 Ure a10 -, -R a11 COOR a12 -, -R a13 OCOR a14 -, or -R a15 OC=OOR a16 - is the case here R a9 ~R a16 Each of these independently represents a single bond or an alkylene group with 1 to 4 carbon atoms. 1 and B 2 Each is independently, more preferably a single bond, -OR a10-1 -, -CH2-, -CH2CH2-, -COOR a12-1 -, or -OCOR a14-1 - is the case here R a10-1 , R a12-1 , R a14-1Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and B 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, -OCO-, or -OCOCH2CH2-.

[0124] From the viewpoint of exhibiting inverse 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. A symmetric structure is preferred when k = 2 and l = 2.

[0125] E 1 and E 2 Each of these groups is independently preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

[0126] P 1 or P 2 Examples of polymerizable groups represented by include epoxy groups, vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are preferred, with acryloyloxy groups being more preferred.

[0127] Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc., and a benzene ring and a naphthalene ring are preferred. Examples of the aromatic heterocyclic ring 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, etc. Among them, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazole ring. Further, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

[0128] 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, still more preferably 14 or more, and particularly preferably 16 or more. Also, it is preferably 30 or less, more preferably 26 or less, still more preferably 24 or less.

[0129] Examples of the aromatic group represented by Ar preferably include the following groups.

[0130]

Chemical formula

[0131] In formulas (Ar-1) to (Ar-23), the * mark represents a connecting part, and Z 0 , Z 1 and Z 2Each 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.

[0132] Q 1 and Q 2 each independently represents —CR 2’ R 3’ —, —S—, —NH—, —NR 2’ —, —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.

[0133] J 1 and J 2 each independently represents a carbon atom or a nitrogen atom.

[0134] Y 1 and Y 2 each independently represents an optionally substituted aromatic hydrocarbon group or an aromatic heterocyclic group.

[0135] 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.

[0136] Y 1 and Y 2Examples of aromatic hydrocarbon groups in this context include C6-C20 aromatic hydrocarbon groups such as phenyl, naphthyl, anthuryl, phenanthuryl, and biphenyl groups, with phenyl and naphthyl groups being preferred and phenyl groups being more preferred. Examples of aromatic heterocyclic groups include C4-C20 aromatic heterocyclic groups containing at least one heteroatom such as a nitrogen atom, oxygen atom, or sulfur atom, such as furyl, pyrrolyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups, with furyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups being preferred.

[0137] Y 1 , and Y 2 Each of these may independently be a substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. A polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. A polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

[0138] Z 0 , Z 1 and Z 2 Each of these is preferably independently a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a cyano group, a nitro group, or a C1-C12 alkoxy group, Z 0 A hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group are more preferably Z 1 and Z 2 Hydrogen atoms, fluorine atoms, chlorine atoms, methyl groups, and cyano groups are more preferred.

[0139] Q 1 , and Q 2 -NH-, -S-, -NR 2’ -, -O- is preferred, R 2’ A hydrogen atom is preferred. Among these, -S-, -O-, and -NH- are particularly preferred.

[0140] Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.

[0141] In equations (Ar-16) to (Ar-23), Y 1 This is the nitrogen atom and Z to which it is bonded. 0 It may also form an aromatic heterocyclic group. Examples of aromatic heterocyclic groups that Ar may have include those mentioned above, such as a pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have substituents. Also, Y 1 This is the nitrogen atom and Z to which it is bonded. 0 In addition, the aforementioned substituted polycyclic aromatic hydrocarbon groups or polycyclic aromatic heterocyclic groups may also be used. Examples include benzofuran rings, benzothiazole rings, and benzoxazole rings.

[0142] Among polymerizable liquid crystal compounds, compounds with a maximum absorption wavelength of 300-400 nm are preferred. When a polymerizable liquid crystal composition contains a photopolymerization initiator, the polymerization reaction and gelation of the polymerizable liquid crystal compound may proceed during long-term storage. However, if the maximum absorption wavelength of the polymerizable liquid crystal compound is 300-400 nm, even if exposed to ultraviolet light during storage, the generation of reactive species from the photopolymerization initiator and the progression of the polymerization reaction and gelation of the polymerizable liquid crystal compound by these reactive species can be effectively suppressed. Therefore, this is advantageous in terms of the long-term stability of the polymerizable liquid crystal composition and can improve the orientation and uniformity of the film thickness of the resulting liquid crystal cured film. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured using an ultraviolet-visible spectrophotometer in a solvent. The solvent is a solvent that can dissolve the polymerizable liquid crystal compound, and examples include chloroform.

[0143] The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal 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, per 100 parts by mass of the solid content of the polymerizable liquid crystal composition. A content of the polymerizable liquid crystal compound within the above range is advantageous from the viewpoint of the orientation of the resulting liquid crystal cured film. In this specification, the solid content of the polymerizable liquid crystal composition refers to all components of the polymerizable liquid crystal composition excluding volatile components such as organic solvents.

[0144] [Laminate containing positive wavelength dispersive λ / 2 plate and positive wavelength dispersive λ / 4 plate] One method for achieving anti-reflective properties is to use a laminate combining a positive wavelength-dispersive λ / 2 plate and a positive wavelength-dispersive λ / 4 plate. For example, one example of a laminate is obtained by combining a layer having optical properties represented by equations (QL1), (QL3), and (QL4) with a layer having optical properties represented by equations (QL2), (QL3), and (QL4) in a specific slow axis relationship.

[0145] 100nm <Re(550)<160nm (QL1) 200nm <Re(550)<320nm (QL2) Re(450) / Re(550)≧1.00 (QL3) 1.00 ≥ Re(650) / Re(550) (QL4)

[0146] Well-known methods for combining the above configurations can be found in Japanese Patent Publication No. 2015-163935 and WO2013 / 137464. From the viewpoint of viewing angle compensation, it is preferable to use a λ / 2 layer containing a polymer of a disc-shaped polymerizable liquid crystal compound and a λ / 4 layer containing a polymer of a rod-shaped polymerizable liquid crystal compound.

[0147] With respect to the transmission axis of the linear polarizer, the slow axis of the positive wavelength dispersive λ / 2 layer is, for example, 10° to 20°, preferably 12° to 18°, and more preferably about 15°, and the slow axis of the positive wavelength dispersive λ / 4 layer is, for example, 70° or more and 80° or less, more preferably 72° or more and 78° or less, and even more preferably about 75°. In another embodiment, with respect to the transmission axis of the linear polarizer, the slow axis of the positive wavelength-dispersive λ / 2 layer is, for example, -10° to -20°, preferably -12° to -18°, more preferably about -15°, and the slow axis of the positive wavelength-dispersive λ / 4 layer is, for example, -70° to -80°, more preferably -72° to -78°, and even more preferably about -75°. In yet another embodiment, with respect to the transmission axis of the linear polarizer, the slow axis of the positive wavelength dispersive λ / 2 layer is 70° to 80°, preferably 72° to 78°, more preferably about 75°, and the slow axis of the positive wavelength dispersive λ / 4 layer is, for example, 10° to 20°, more preferably 12° to 18°, and even more preferably about 15°. In yet another embodiment, with respect to the transmission axis of the linear polarizer, the slow axis of the positive wavelength dispersive λ / 2 layer is -70° to -80°, preferably -72° to -78°, more preferably about -75°, and the slow axis of the positive wavelength dispersive λ / 4 layer is, for example, -10° to -20°, more preferably -12° to -18°, and even more preferably about -15°.

[0148] Examples of disc-shaped polymerizable liquid crystal compounds include compounds containing a group represented by formula (W) (hereinafter sometimes referred to as polymerizable liquid crystal compound (C)). [ka] [In formula (W), R 40 This represents the following equations (W-1) to (W-5).

[0149] [ka]

[0150] X 40 and Z 40 m2 represents an alkanediyl group having 1 to 12 carbon atoms, and the hydrogen atoms in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, or the hydrogen atoms in the alkoxy group may be substituted with a halogen atom. Furthermore, the -CH2- constituting the alkanediyl group may be replaced with -O- or -CO-. Also, m2 is an integer from 1 to 20.

[0151] Examples of rod-shaped polymerizable liquid crystal compounds include those represented by formulas (I), (II), (III), (IV), (V), or (VI). P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (I) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (II) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (III) P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (IV) P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (V) P11-B11-E11-B12-A11-B13-A12-F11 (VI) A11 represents a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. The hydrogen atoms in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted with halogen atoms, C1-C6 alkyl groups, C1-C6 alkoxy groups, cyano groups, or nitro groups, and the hydrogen atoms in the C1-C6 alkyl groups and the C1-C6 alkoxy groups may be substituted with fluorine atoms.

[0152] B11 is -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO-NR 16 -, -NR16 -CO-, -CO-, -CS-, or single bond. 16 This represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0153] B12 and B13 are independently -C≡C-, -CH=CH-, -CH2-CH2-, -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)-, -OCH2-, -OCF2-, -CH2O-, -CF2O-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, or a single bond.

[0154] E11 represents an alkanediyl group having 1 to 12 carbon atoms. The hydrogen atoms in the alkanediyl group may be substituted with an alkoxy group having 1 to 5 carbon atoms, and the hydrogen atoms in the alkoxy group may be substituted with a halogen atom. Furthermore, the -CH2- group constituting the alkanediyl group may be replaced with -O- or -CO-.

[0155] The number of carbon atoms in the aromatic hydrocarbon group and alicyclic hydrocarbon group of A11 is preferably in the range of 3 to 18, more preferably in the range of 5 to 12, and particularly preferably 5 or 6. As A11, cyclohexane-1,4-diyl group and 1,4-phenylene group are preferred.

[0156] As E11, a linear alkanediyl group having 1 to 12 carbon atoms is preferred. The -CH2- group constituting the alkanediyl group may be replaced with -O-.

[0157] Specifically, examples include linear alkanediyl groups having 1 to 12 carbon atoms, such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, and dodecane-1,12-diyl group; and -CH2-CH2-O-CH2-CH2-, -CH2-CH2-O-CH2-CH2-O-CH2-CH2-, and -CH2-CH2-O-CH2-CH2-O-CH2-CH2-.

[0158] For B11, -O-, -S-, -CO-O-, and -O-CO- are preferred, with -CO-O- being the most preferred among them.

[0159] For B12 and B13, independently, -O-, -S-, -C(=O)-, -C(=O)-O-, -OC(=O)-, and -OC(=O)-O- are preferred, with -O- or -OC(=O)-O- being more preferred.

[0160] As for the polymerizable group represented by P11, radical polymerizable groups or cationic polymerizable groups are preferred in terms of high polymerization reactivity, particularly photopolymerization reactivity, and are easy to handle, as well as the liquid crystal compound itself is easy to manufacture. Therefore, the polymerizable group is preferably a group represented by the following formulas (P-11) to (P-15).

[0161] [ka] [In formulas (P-11) to (P-15), R 17 ~R 21 Each of these independently represents an alkyl group or hydrogen atom having 1 to 6 carbon atoms.

[0162] Specific examples of the groups represented by equations (P-11) to (P-15) include the groups represented by equations (P-16) to (P-20) below.

[0163] [ka]

[0164] P11 is preferably a group represented by formulas (P-14) to (P-20), and more preferably a vinyl group, a p-stilbene group, an epoxy group, or an oxetanyl group.

[0165] It is even more preferable that the group represented by P11-B11- is an acryloyloxy group or a methacryloyloxy group.

[0166] (In the formula, A12 to A14 are each independently synonymous with A11, B14 to B16 are each independently synonymous with B12, B17 is synonymous with B11, and E12 is synonymous with E11. F11 represents 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 hydroxyl group, a methylol group, a formyl group, a sulfo group (-SO3H), a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or a halogen atom, and the alkyl group and alkoxy group are composed of -CH 2 - may be replaced with -O-.

[0167] [Other configurations] The first and second liquid crystal phase difference layers may be laminates in which at least one liquid crystal phase difference layer is tilt-oriented or cholesterically oriented, in addition to the above-mentioned configuration of a combination of a positive wavelength dispersive λ / 2 layer and a positive wavelength dispersive λ / 4 layer. Examples of well-known configurations include those described in WO2021 / 060378, WO2021 / 132616, and WO2021 / 132624.

[0168] <Positive C-plate> Positive C plates are not particularly limited as long as they have anisotropy in the thickness direction, but if they are not tilt-oriented or cholesteric-oriented, they have optical properties represented by equation (PC3). nx≒ny <nz (PC3)

[0169] The in-plane phase difference value Re(550) of the positive C plate at a wavelength of 550 nm is typically in the range of 0 to 10 nm, preferably in the range of 0 to 5 nm. Furthermore, the phase difference value Rth(550) in the thickness direction at a wavelength of 550 nm is typically in the range of -170 nm to -10 nm, preferably in the range of -150 nm to -20 nm, and more preferably in the range of -100 nm to -40 nm. If the phase difference value in the thickness direction is within this range, the anti-reflection characteristics from oblique directions can be further improved.

[0170] The thickness of the positive C plate is usually 10 μm or less, preferably 5 μm or less, and more preferably 0.3 μm to 3 μm.

[0171] The positive C plate is preferably a coating layer formed by polymerizing one or more polymerizable liquid crystal compounds. More preferably, it is a rod-shaped polymerizable liquid crystal compound.

[0172] Examples of rod-shaped polymerizable liquid crystals include compounds represented by formulas (I), (II), (III), (IV), (V), or (VI). P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (I) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (II) P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (III) P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (IV) P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (V) P11-B11-E11-B12-A11-B13-A12-F11 (VI) (In the formula, A12 to A14 are each independently synonymous with A11, B14 to B16 are each independently synonymous with B12, B17 is synonymous with B11, and E12 is synonymous with E11. F11 represents a hydrogen atom, a C1-C13 alkyl group, a C1-C13 alkoxy group, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxyl group, a methylol group, a formyl group, a sulfo group (-SO3H), a carboxyl group, a C1-C10 alkoxycarbonyl group, or a halogen atom, and the -CH2- constituting the alkyl group and alkoxy group may be replaced with -O-.)

[0173] The content of the polymerizable liquid crystal compound in the liquid crystal phase difference layer 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, per 100 parts by mass of the solid content of the liquid crystal phase difference layer forming composition. A content of polymerizable liquid crystal compound within the above range is advantageous from the viewpoint of the orientation of the resulting liquid crystal phase difference layer. In this specification, the solid content of the liquid crystal phase difference layer forming composition refers to all components of the polymerizable liquid crystal composition excluding volatile components such as organic solvents.

[0174] <Composition for forming liquid crystal retardation layer> A liquid crystal phase difference layer is typically formed by applying a liquid crystal phase difference layer-forming composition containing a polymerizable liquid crystal compound onto an alignment film formed as needed on a substrate, and then polymerizing and curing the polymerizable liquid crystal compound in an oriented state.

[0175] [Orientation film and composition for forming orientation film] The alignment film has an orientation-regulating force that causes polymerizable liquid crystal compounds to be liquid crystal oriented in a desired direction.

[0176] Alignment films facilitate the liquid crystal alignment of polymerizable liquid crystal compounds. The state of liquid crystal alignment, such as horizontal alignment, vertical alignment, hybrid alignment, and tilted alignment, changes depending on the properties of the alignment film and the polymerizable liquid crystal compound, and any combination can be arbitrarily selected. For example, if the alignment film is a material that exhibits horizontal alignment as an alignment restricting force, the polymerizable liquid crystal compound can form horizontal alignment or hybrid alignment. If the material exhibits vertical alignment, the polymerizable liquid crystal compound can form vertical alignment or tilted alignment. Expressions such as horizontal and vertical refer to the direction of the optical axis of the oriented polymerizable liquid crystal compound with respect to the optical anisotropy layer plane. For example, vertical alignment means that the optical axis of the oriented polymerizable liquid crystal compound is perpendicular to the optical anisotropy layer plane. Here, perpendicular means 90° ± 20° with respect to the optical anisotropy layer plane.

[0177] The orientation-regulating force can be arbitrarily adjusted by surface conditions and rubbing conditions if the orientation film is formed from an orientation-oriented polymer, and by polarization irradiation conditions, etc., if it is formed from a photo-oriented polymer. Furthermore, liquid crystal orientation can also be controlled by selecting physical properties such as surface tension and liquid crystalline properties of the polymerizable liquid crystal compound.

[0178] The alignment film formed between the substrate and the optically anisotropic layer is preferably insoluble in the solvent used to form the optically anisotropic layer on the alignment film, and also has heat resistance for solvent removal and heat treatment for liquid crystal alignment. Examples of alignment films include alignment films made of aligning polymers, photo-alignment films, groove alignment films, and stretched films stretched in the orientation direction. When applied to long roll-shaped films, photo-alignment films are preferred because the orientation direction can be easily controlled.

[0179] The thickness of the orientation film is typically 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 nm to 300 nm.

[0180] Examples of oriented polymers used in rubbing orientation films include polyamides and gelatins having amide bonds in their molecules, polyimides having imide bonds in their molecules and their hydrolysates 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 oriented polymers may be used individually or in combination of two or more.

[0181] One method of rubbing involves wrapping a rubbing cloth around a rotating rubbing roll and bringing the film of the oriented polymer, formed on the surface of the substrate by applying an oriented polymer composition to the substrate and annealing it, into contact with the roll.

[0182] Photo-alignment films consist of polymers, oligomers, or monomers having photoreactive groups. An orientation-regulating force can be obtained by irradiating the photo-alignment film with polarized light. Photo-alignment films are preferable because the direction of the orientation-regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0183] A photoreactive group is a group that generates liquid crystal alignment ability upon irradiation with light. Specifically, it is a group that generates a photoreaction that is the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization, dimerization, photocrosslinking, or photodegradation, upon irradiation with light. Among these photoreactive groups, those that cause dimerization or photocrosslinking are preferred in terms of their excellent orientation properties. As photoreactive groups that can generate such reactions, those having unsaturated bonds, especially double bonds, are preferred, and more preferably groups having at least one selected from the group consisting of carbon-carbon double bonds (C=C bonds), carbon-nitrogen double bonds (C=N bonds), nitrogen-nitrogen double bonds (N=N bonds), and carbon-oxygen double bonds (C=O bonds).

[0184] 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 viewpoint of ease of controlling reactivity and the expression of orientation-regulating power during photo-orientation. 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, and formazan groups, as well as those with azoxybenzene as their 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.

[0185] Polarized light can be irradiated either by directly irradiating the film surface with polarized light, or by irradiating the substrate with polarized light and allowing it to pass through. Furthermore, it is particularly preferable that the polarized light be substantially parallel. The wavelength of the irradiated polarized light should be in a wavelength range in which the photoreactive groups of the polymer or monomer having photoreactive groups can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 to 400 nm is particularly preferred. Examples of light sources used for this 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, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being more preferred. These lamps are preferred because they have a high emission intensity of ultraviolet light at a wavelength of 313 nm. Polarized light can be irradiated by passing the light from the light source through a suitable polarizer. Such polarizers can include polarizing filters, polarizing prisms such as Grant-Thomson and Grant-Taylor, and wire grid type polarizers.

[0186] The alignment film forming composition may contain a leveling agent as needed. As the leveling agent, a silicone-based leveling agent and / or a fluorine-based leveling agent, as described in the section on the liquid crystal phase difference layer later, can be used. The leveling agent is usually preferably contained in the solid content of the alignment film forming composition at 0.001 to 3% by mass, more preferably 0.01 to 3% by mass, and even more preferably 0.1 to 3% by mass.

[0187] (Composition for forming liquid crystal retardation layer) The content of polymerizable liquid crystal compounds in the liquid crystal phase difference layer 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, per 100 parts by mass of solid content of the liquid crystal phase difference layer forming composition. A content of polymerizable liquid crystal compounds within the above range is advantageous from the viewpoint of the orientation of the resulting liquid crystal phase difference layer. In this specification, the solid content of the liquid crystal phase difference layer forming composition refers to all components of the liquid crystal phase difference layer forming composition excluding volatile components such as organic solvents.

[0188] In addition to the polymerizable liquid crystal compound, the composition for forming a liquid crystal phase difference layer may further contain reactive additives such as solvents, leveling agents, polymerization initiators, photosensitizers, polymerization inhibitors, crosslinking agents, and adhesives.

[0189] <Solvent> Compositions for forming liquid crystal phase difference layers may contain solvents. Generally, polymerizable liquid crystal compounds have high viscosity, so dissolving them in a solvent makes application easier, and as a result, it is often easier to form the liquid crystal phase difference layer. The solvent is preferably one that can completely dissolve the polymerizable liquid crystal compound, and is also preferably an inert solvent in the polymerization reaction of the polymerizable liquid crystal compound.

[0190] Examples of solvents include alcoholic 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 individually or in combination of two or more.

[0191] The solvent content is preferably 50 to 98% by mass relative to the total amount of the liquid crystal phase difference layer forming composition. In other words, the solid content in the liquid crystal phase difference layer forming composition is preferably 2 to 50% by mass, and more preferably 5 to 30% by mass. When the solid content is 50% by mass or less, the viscosity of the liquid crystal phase difference layer forming composition decreases, resulting in a more uniform thickness of the liquid crystal phase difference layer, which tends to reduce unevenness in the liquid crystal phase difference layer. Furthermore, the solid content can be determined considering the thickness of the optical anisotropy layer to be manufactured.

[0192] <Leveling agent> The liquid crystal phase difference layer forming composition may contain a leveling agent. A leveling agent is an additive that adjusts the fluidity of the composition and makes the film obtained by coating the composition flatter. Examples include silicone-based leveling agents, acrylic-based leveling agents, and fluorine-based leveling agents. Among these, silicone-based leveling agents and fluorine-based leveling agents are preferred because they have excellent function in reducing the tension of the film surface obtained by coating the composition.

[0193] Examples of silicone-based leveling agents include leveling agents having a polyorganosiloxane skeleton.

[0194] Examples of groups bonded to silicon atoms in polyorganosiloxanes (silicon atoms that form siloxane bonds) include hydrocarbon groups. Silicone-based leveling agents may have two hydrocarbon groups bonded to a silicon atom. There are no limitations on the groups bonded to the silicon atom, but alkyl groups and aryl groups having 1 to 10 carbon atoms are preferred, more preferably methyl groups and phenyl groups, and even more preferably methyl groups. The group bonded to the silicon atom may be one type or two or more types. Furthermore, the number of repeating siloxane units (degree of polymerization) is not particularly limited, but is preferably 2 to 10,000, more preferably 3 to 5,000, and even more preferably 5 to 1,000.

[0195] Commercially available silicone leveling agents can be used, such as SH710 (manufactured by Toray Dow Corning Co., Ltd.), BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325, BYK-330, BYK -331, BYK-333, BYK-337, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-370, BYK-377, BYK-378, BYK-3455, BYK-UV3510 (all manufactured by Big Chemie Japan Co., Ltd.), KF-945, KF-6015, KF-60 Examples include 20 (manufactured by Shin-Etsu Chemical Co., Ltd.), TEGORad2300, TEGORad2200N, TEGORad2011 (manufactured by Degussa), and BYK-UV3500, BYK-UV3505, BYK-3510, BYK-UV3530, BYK-UV3570, BYK-UV3575, BYK-UV3576 (all manufactured by BIC Chemie Japan Co., Ltd.), KP-422, KP-416, KP-418, KP-410, KP-411, KP-412, KP-413, KP-423, KP-414, KP-415, KP-420, KP-983 (all manufactured by Shin-Etsu Chemical Co., Ltd.), which have radical polymerizable groups such as (meth)acryloyl groups added to the polyether chain.

[0196] The content of the silicone-based leveling agent in the liquid crystal phase difference layer forming composition is preferably 0.001 to 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and even more preferably 0.1 to 1.5 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound.

[0197] Fluorine-based leveling agents are not particularly limited, but examples include leveling agents having a fluoroaliphatic hydrocarbon skeleton. The above-mentioned fluoroaliphatic hydrocarbon skeleton is not particularly limited, but examples include fluoromethane, fluoroethane, fluoropropane, fluoroisopropane, fluorobutane, fluoroisobutane, fluorot-butane, fluoropentane, fluorohexane, and other fluoroalkanes having 1 to 10 carbon atoms. The fluoroaliphatic hydrocarbon skeleton only needs to have at least some of its hydrogen atoms replaced by fluorine atoms, but it may also be a perfluoroaliphatic hydrocarbon skeleton in which all of its hydrogen atoms are replaced by fluorine atoms.

[0198] Furthermore, the above-mentioned fluoroaliphatic hydrocarbon skeleton may form a polyfluoroalkylene ether skeleton, which is a repeating unit via ether bonds. The fluoroaliphatic hydrocarbon group used as the repeating unit is not particularly limited, but examples include fluoroC1-4 alkylene groups such as fluoromethylene, fluoroethylene, fluoropropylene, and fluoroisopropylene. The above-mentioned fluoroaliphatic hydrocarbon group may be one type or two or more types. The number of repeating units (degree of polymerization) of the fluoroalkylene ether units is not particularly limited, but is preferably 10 to 10,000, more preferably 30 to 5,000, and even more preferably 50 to 1,000.

[0199] As examples of the fluorine-based leveling agent, commercially available products can be used. For example, Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-471, F-477, F-479, F-482, F-483, F-281, F-253, F-251, F-114, F-510, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561, F-562, F-563, F-565, F-568, F-569, F-570, F-572, F-574, F-575, F-576, R-40, R-41, R-94, RS-56, RS-72-K, RS-75, RS-76-E, RS-76-NS, RS-78, RS-90, DS-21 (DIC Corporation); Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40 and SA-100 (AGC Seimi Chemical Co., Ltd.); E1830, E5844 (Daikin Fine Chemical Research Institute Co., Ltd.); F-Top EF301, F-Top EF303, F-Top EF351 and F-Top EF352 (Mitsubishi Materials Electronic Chemicals Co., Ltd.) can be mentioned.

[0200] The content of the fluorine-based leveling agent in the composition for forming a liquid crystal retardation layer is preferably 0.001 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 1.5 parts by mass, and still more preferably 0.1 parts by mass to 1.5 parts by mass with respect to 100 parts by mass of the above polymerizable liquid crystal compound.

[0201] When the composition for forming a liquid crystal retardation layer contains various leveling agents, it is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass with respect to 100 parts by mass of the content of the polymerizable liquid crystal compound. Note that the composition for forming an optically anisotropic layer may contain two or more leveling agents.

[0202] <Polymerization initiator> The composition for forming a liquid crystal retardation layer 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. From the viewpoint of not depending on the phase state of a thermotropic liquid crystal, a photopolymerization initiator that generates active radicals by the action of light is preferable as the polymerization initiator.

[0203] As long as the photopolymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound, known photopolymerization initiators can be used. Specifically, photopolymerization initiators capable of generating active radicals or an acid by the action of light can be mentioned. Among them, photopolymerization initiators that generate radicals by the action of light are preferable. The photopolymerization initiator can be used alone or in combination of two or more.

[0204] As the photopolymerization initiator, known photopolymerization initiators can be used. For example, as the photopolymerization initiator that generates active radicals, self-cleaving benzoin-based compounds, acetophenone-based compounds, hydroxyacetophenone-based compounds, α-aminoacetophenone-based compounds, oxime ester-based compounds, acylphosphine oxide-based compounds, azo-based compounds, etc. can be used, and hydrogen abstraction-type benzophenone-based compounds, alkylphenone-based compounds, benzoin ether-based compounds, benzyl ketal-based compounds, dibenzosuberone-based compounds, anthraquinone-based compounds, xanthone-based compounds, thioxanthone-based compounds, halogenoacetophenone-based compounds, dialkoxyacetophenone-based compounds, halogenobisimidazole-based compounds, halogenotriazine-based compounds, triazine-based compounds, etc. can be used. As the photopolymerization initiator that generates an acid, iodonium salts and sulfonium salts, etc. can be used. From the viewpoint of excellent reaction efficiency at low temperatures, self-cleaving photopolymerization initiators are preferable, and particularly acetophenone-based compounds, hydroxyacetophenone-based compounds, α-aminoacetophenone-based compounds, and oxime ester-based compounds are preferable.

[0205] The content of the polymerization initiator in the liquid crystal phase difference layer forming composition can be appropriately adjusted depending on the type and amount of 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, per 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 orientation of the polymerizable liquid crystal compound.

[0206] <Sensitizer> The liquid crystal phase difference layer forming composition may contain a sensitizer. Photosensitizers are preferred as sensitizers. Examples of such sensitizers include xanthone compounds such as xanthones and thioxanthones (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and alkoxy group-containing anthracene (e.g., dibutoxyanthracene, etc.); phenothiazines and rubrene, etc.

[0207] When a liquid crystal phase difference layer forming composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the liquid crystal phase difference layer forming composition can be further promoted. The amount of such 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, per 100 parts by mass of the polymerizable liquid crystal compound.

[0208] <Antioxidant> From the viewpoint of ensuring stable polymerization reactions, the liquid crystal phase difference layer forming composition may contain an antioxidant. The antioxidant allows for control over the degree of polymerization of the polymerizable liquid crystal compound.

[0209] The antioxidant may be, for example, a primary antioxidant selected from phenolic antioxidants, amine antioxidants, quinone antioxidants, and nitroso antioxidants, or a secondary antioxidant selected from phosphorus antioxidants and sulfur antioxidants.

[0210] When the liquid crystal phase difference layer forming composition contains an antioxidant, the antioxidant content 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, per 100 parts by mass of the polymerizable liquid crystal compound. The antioxidant can be used alone or in combination of two or more types. When the antioxidant content is within the above range, polymerization can be carried out without disrupting the orientation of the polymerizable liquid crystal compound.

[0211] <Reactive additives> The liquid crystal phase difference layer forming composition may contain reactive additives. Preferred reactive additives have carbon-carbon unsaturated bonds, active hydrogen reactive groups, or thiol groups within their molecules. Here, "active hydrogen reactive group" refers to a group that reacts to active hydrogen groups such as carboxyl groups (-COOH), hydroxyl groups (-OH), and amino groups (-NH2). Typical examples include glycidyl groups, oxazoline groups, carbodiimide groups, aziridine groups, imide groups, isocyanate groups, thioisocyanate groups, and maleic anhydride groups. The number of reactive groups in a reactive additive is typically 1 to 20, preferably 1 to 10.

[0212] (Adhesive layer 40) The adhesive layer 40 is positioned between the first liquid crystal phase difference layer 30 and the second liquid crystal phase difference layer 50, bonding them together. The adhesive layer 40 may be in direct contact with the first liquid crystal phase difference layer 30 and / or the second liquid crystal phase difference layer 50. If at least one of the first liquid crystal phase difference layer 30 and the second liquid crystal phase difference layer 50 is formed on an alignment film, the adhesive layer 40 may be in contact with the alignment film. The thickness of the adhesive layer 40 is 20 to 200 nm. The thickness of the adhesive layer may be 25 nm or more, 30 nm or more, or 35 nm or more. The thickness of the adhesive layer 40 may be 160 nm or less, 150 nm or less, 130 nm or less, 120 nm or less, or 100 nm or less.

[0213] The material of the adhesive layer 40 is not particularly limited and may be a cationic polymerizable adhesive or a radical polymerizable adhesive, but from the viewpoint of satisfying the thickness of the adhesive layer 40 described above, it is preferable to use a water-based adhesive layer.

[0214] The adhesive layer 40, which is a water-based adhesive layer, can be formed by drying the water-based adhesive composition. The water-based adhesive composition is an aqueous solution obtained by dissolving an adhesive resin in water, and from the viewpoint of making a thin adhesive, the solid content concentration of the water-based adhesive composition is preferably 0.5 to 20% by mass, and more preferably 1% to 15% by mass. The water-based adhesive composition may contain crosslinking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine compounds, methylol compounds, isocyanate compounds, amine compounds, and polyvalent metal salts.

[0215] Examples of resins for the water-based adhesive layer 40 include urethane resin and polyvinyl alcohol (PVA) resin, with PVA resin being preferred. When a polyvinyl alcohol-based resin is used as the resin for the adhesive layer 40, the polyvinyl alcohol-based resin may be a polyvinyl alcohol resin such as partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, or a modified polyvinyl alcohol-based resin. Examples of modified polyvinyl alcohol-based resins include carboxyl group-modified polyvinyl alcohol-based resins and acetoacetyl group-modified polyvinyl alcohol-based resins.

[0216] The average degree of polymerization of the polyvinyl alcohol resin (preferably acetoacetyl-modified polyvinyl alcohol resin) is preferably 100 to 5500, and more preferably 500 to 4500, from the viewpoint of adhesion.

[0217] The degree of saponification of polyvinyl alcohol-based resins (preferably acetoacetyl-modified polyvinyl alcohol-based resins) is typically 80 mol% to 100 mol%, and preferably 85 mol% or more.

[0218] In the acetoacetyl group-modified polyvinyl alcohol-based resin, the degree of modification (amount of modification) by the acetoacetyl group is usually 0.1 mol% to 40 mol%, preferably 0.5 mol% to 20 mol% from the viewpoint of adhesion.

[0219] Among them, the resin of the adhesive layer 40 is preferably a polyvinyl alcohol-based resin, and more preferably an acetoacetyl group-modified polyvinyl alcohol-based resin. That is, as the adhesive layer 40, a dried product and / or a cured product layer of an aqueous adhesive composition containing a polyvinyl alcohol-based resin is preferable.

[0220] In order to obtain such an adhesive layer with a thickness, for example, an adhesive solution such as an aqueous adhesive solution is applied to one surface of either the first liquid crystal retardation layer 30 or the second liquid crystal retardation layer 50 to form a liquid film, and the other of the first liquid crystal retardation layer 30 or the second liquid crystal retardation layer 50 is laminated on the liquid film, and then the laminate is heated or the like to dry the solvent such as water in the liquid film to form a thin adhesive layer 40. After the drying process, ultraviolet rays or electron beams can be irradiated as necessary.

[0221] At this time, by reducing the concentration of the resin contained in the adhesive solution to be applied, an adhesive layer with a thickness of 20 to 200 nm can be formed even if a liquid film on the order of μm such as about 20 μm is formed.

[0222] In addition, when the thicknesses of the first liquid crystal retardation layer 30 and the second liquid crystal retardation layer 50 are small, it is easy to dry the liquid film. Therefore, it is preferable that the thicknesses of both the first liquid crystal retardation layer 30 and the second liquid crystal retardation layer 50 are 10 μm or less, preferably 5 μm or less, and more preferably 0.3 μm or more and 3 μm or less.

[0223] (In-plane average refractive index of the first and second liquid crystal retardation layers and the adhesive layer) The in-plane average refractive index of the first and second liquid crystal retardation layers may be 1.45 to 1.65, preferably 1.50 to 1.60, and more preferably 1.53 to 1.58. The in-plane average refractive index of the adhesive layer is 1.45 to 1.60, more preferably 1.48 to 1.57, and even more preferably 1.51 to 1.54.

[0224] (outer adhesive layer) The optical laminate 400 may have an outer adhesive layer 500 on the side opposite to the adhesive layer 40 with respect to the second liquid crystal phase difference layer 50. There are no particular limitations on the material or thickness of the outer adhesive layer 500; for example, various known adhesives such as acrylic adhesives, urethane adhesives, and silicone adhesives can be used. The thickness of the outer adhesive layer can be 1 μm or more and 100 μm or less, and preferably 5 μm or more and 50 μm or less.

[0225] (Mechanism of action) This embodiment offers the following advantages. Specifically, even when a protective layer is present on only one side of the linear polarizer, this embodiment can suppress the disappearance of the dichroic dye from the linear polarizer in high-temperature, high-humidity environments, and can provide an optical laminate in which the reduction in visibility due to unevenness is suppressed. The reason for this is unknown, but the following mechanism is considered.

[0226] Since the adhesive layer 150 has a relatively high storage modulus, the crosslinking density is high, which hinders the movement of dichroic dyes such as iodine from the linear polarizer to the phase difference layer laminate in high-temperature environments. Furthermore, because the adhesive layer 150 has a relatively thin thickness, the amount of water contained in the adhesive layer is reduced, which suppresses the detachment of dichroic dyes such as iodine from the linear polarizer in high-temperature environments.

[0227] Furthermore, since the thickness of the adhesive layer 40 is appropriate at 20-200 nm, interference between the first liquid crystal phase difference layer 30 and the second liquid crystal phase difference layer 50 occurs in the ultraviolet region, suppressing the visibility of interference unevenness in visible light. In addition, because the thickness of the adhesive layer 40 is not too thin, adhesion unevenness due to minute air bubbles caused by poor adhesion is also suppressed, which is thought to improve visibility.

[0228] Furthermore, if the phase difference layer laminate satisfies equations (1) and (2) above, it has the effect of effectively suppressing the reflection of ambient light by electrodes in the OLED across the entire visible light spectrum.

[0229] <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 positioned on the viewing side of the image display element (image display cell). The optical laminate can be bonded to the image display element using an adhesive layer.

[0230] The image display device is not particularly limited and examples include organic electroluminescent (organic EL) display devices, inorganic electroluminescent (inorganic EL) display devices, liquid crystal display devices, and electroluminescent display devices.

[0231] Image display devices can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signs, measuring instruments or gauges, office equipment, medical equipment, computer equipment, etc. [Examples]

[0232] The present invention will be described more specifically 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 mass percent and parts by mass, respectively.

[0233] <Measuring Thickness> The layer thickness was measured using a contact-type film thickness measuring device (Nikon Corporation "MS-5C"). The thickness of the polarizer and alignment film was measured using a scanning white light interference microscope (Hitachi High-Tech Science Corporation "VS1000"). The thickness of the water-based adhesive layer was measured using an AFM (Shimadzu Corporation "SPM9700HT") on a cross-section obtained by cross-sectional processing of the phase difference layer using a microtome.

[0234] <Measuring Phase Difference Values> The phase difference values ​​of the first liquid crystal phase difference layer and the second liquid crystal phase difference layer were measured using a phase difference measuring device (KOBRA-WR, manufactured by Oji Instruments Co., Ltd.). The phase difference values ​​of the phase difference layer were measured using a phase difference measuring device (KOBRA-PR, manufactured by Oji Instruments Co., Ltd.) after peeling the separator film 2 from the optical laminate and bonding it to the glass. The in-plane phase difference values ​​for light at wavelengths of 450 nm, 550 nm, and 650 nm were determined from Cauchy's dispersion formula obtained from the measurement results of the in-plane phase difference values ​​for light at wavelengths of 448.2 nm, 498.6 nm, 548.4 nm, 587.3 nm, 628.7 nm, and 748.6 nm.

[0235] <Preparation of water-based adhesive composition> At room temperature, the following compositional liquids A and B were mixed in a mass ratio of 1:1 and stirred for 30 minutes to prepare a water-based adhesive composition for forming a water-based adhesive layer. Composition Solution A: An acetoacetyl-modified polyvinyl alcohol resin (Mitsubishi Chemical Corporation, "Gosenol Z200") with a saponification degree of 99.2 mol% was dissolved in water (distilled water) to prepare an aqueous PVA solution with a solid content of 8% by mass. The prepared 8% by mass PVA solution and a 40% aqueous glyoxal solution were mixed in a mass ratio of 3.0:0.7, and the mixture was further adjusted so that the total solid content was 3 parts per 100 parts of water to prepare Composition Solution A. Composition Solution B: An acetoacetyl-modified polyvinyl alcohol resin (Mitsubishi Chemical Corporation, "Gosenol Z200") with a saponification degree of 99.2 mol% was dissolved in water (distilled water) to prepare an aqueous PVA solution with a solid content of 8% by mass. The prepared 8% by mass PVA solution and zinc chloride were mixed in a mass ratio of 3.0:0.09, and the total solid content was further adjusted to 3 parts per 100 parts of water to prepare Composition Solution B. The in-plane mean refractive index of the dried and cured product of the water-based adhesive composition was 1.52.

[0236] <Preparation of the laminated layer (1)> (Preparation of acrylic resin solution (1)) A reaction vessel equipped with a condenser, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 100 parts ethyl acetate, 99.0 parts butyl acrylate, 0.5 parts 2-hydroxyethyl acrylate, and 0.5 parts acrylic acid. The internal temperature was raised to 55°C while replacing the air in the apparatus with nitrogen gas to eliminate oxygen. Subsequently, the entirety of a solution prepared by dissolving 0.12 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was added. After adding the polymerization initiator, the temperature was maintained at this level for 1 hour. Then, while maintaining the internal temperature at 54-56°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr. When the concentration of the (meth)acrylic resin reached 35% by mass, the addition of ethyl acetate was stopped, and the temperature was maintained at this level for another 6 hours from the start of ethyl acetate addition. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, and acrylic resin solution (1) was prepared. The obtained 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 "TSKgel GMH" manufactured by Tosoh Corporation as the column in the GPC instrument. HR Two "-H(S)" units were connected in series, and tetrahydrofuran was used as the eluate. The measurement was performed under the following conditions: sample concentration of 2 mg / mL, sample introduction volume of 100 μL, temperature of 40°C, and flow rate of 1 mL / min, in terms of standard polystyrene equivalent.

[0237] (Preparation of adhesive layer forming composition (1)) To 80 parts of the solid content of the acrylic resin solution (1) obtained above, 20 parts (solid content) of difunctional acrylate (obtained from Shin Nakamura Chemical Industry Co., Ltd.; product number "A-DOG"), 2.5 parts on an active ingredient basis of a crosslinking agent (manufactured by Tosoh Corporation: product name "Coronate L" (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass))), 1.5 parts of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: product name "Irgacure 500"), and 0.3 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: product name "KBM-403") were added, and then ethyl acetate was added to bring the solid content concentration to 13% to obtain a composition (1) for forming an adhesive layer. A-DOG is a diacrylate of an acetal compound of hydroxypivalaldehyde and trimethylolpropane and has the structure of the following formula. [Chemical formula]

[0238] (Preparation of Adhesive Sheet (1)) The composition (1) for forming an adhesive layer prepared above was applied to the release-treated surface of a separate film 1 made of a polyethylene terephthalate film subjected to a release treatment ["PLZ-383030" obtained from Lintec Corporation] using an applicator so that the thickness after drying would be 5 μm, and dried at 100°C for 1 minute to produce a bonding layer (1). Next, the surface of the obtained bonding layer (1) opposite to the separator film was bonded to the release-treated surface of a separate film 2 made of a polyethylene terephthalate film subjected to a release treatment ["PLR-381031" obtained from Lintec Corporation]. Subsequently, ultraviolet rays were irradiated under the following conditions to produce an adhesive sheet (1) composed of separator film 1 / bonding layer (1) / separator film 2. The storage elastic modulus of the bonding layer (1) at 25°C was 0.6 MPa, and the refractive index with respect to light having a wavelength of 589 nm was 1.48. The saturation moisture content of the bonding layer (1) was 1.1%. <UV Irradiation Conditions> · Using a Fusion UV lamp system (manufactured by Fusion UV Systems) and an H bulb · Integrated light quantity: 250 mJ / cm 2

[0239] (Preparation of Bonding Layer (2)) (Preparation of Adhesive Sheet (2)) An adhesive sheet (2) was obtained in the same manner as the method for preparing the adhesive sheet (1), except that a bonding layer (2) was prepared by applying using an applicator so that the thickness after drying would be 15 μm.

[0240] (Preparation of Bonding Layer (3)) (Preparation of Acrylic Resin Solution (2)) A reaction vessel equipped with a condenser, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 81.8 parts ethyl acetate, 90.0 parts butyl acrylate, 5.0 parts methyl acrylate, and 5.0 parts acrylic acid. The internal temperature was raised to 55°C while replacing the air in the apparatus with nitrogen gas to eliminate oxygen. Subsequently, the entirety of a solution prepared by dissolving 0.15 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was added. After adding the polymerization initiator, the temperature was maintained at this level for 1 hour. Then, while maintaining the internal temperature at 54-56°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr. When the concentration of the (meth)acrylic resin reached 35% by mass, the addition of ethyl acetate was stopped, and the temperature was maintained at this level for another 6 hours from the start of ethyl acetate addition. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, and acrylic resin solution (2) was prepared. The obtained 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 "TSKgel GMH" manufactured by Tosoh Corporation as the column in the GPC instrument. HR Two "-H(S)" units were connected in series, tetrahydrofuran was used as the eluate, and measurements were taken using standard polystyrene equivalents under the following conditions: sample concentration of 2 mg / mL, sample introduction volume of 100 μL, temperature of 40°C, and flow rate of 1 mL / min.

[0241] (Preparation of the adhesive layer forming composition (2)) To 100 parts of the solid content of the acrylic resin solution (2) obtained above, 0.15 parts on an active ingredient basis of a crosslinking agent (manufactured by Tosoh Corporation: trade name "Coronate L" (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass)) and 0.2 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added, and then ethyl acetate was added to bring the solid content concentration to 13% to obtain a composition (2) for forming an adhesive layer.

[0242] (Preparation of adhesive sheet (3)) The adhesive layer-forming composition (2) prepared above was applied using an applicator to the release-treated surface of a separator film 1 (PLR-382190, obtained from Lintec Corporation) made of release-treated polyethylene terephthalate film, so that the thickness after drying was 25 μm, and dried at 100°C for 1 minute to produce a laminated layer (3). Next, the surface of the obtained laminated layer (3) opposite to the separator film was laminated to the release-treated surface of a separator film 2 (PET-251130, obtained from Lintec Corporation) made of release-treated polyethylene terephthalate film, to produce an adhesive sheet (3) consisting of separator film 1 / laminated layer (3) / separator film 2. The storage modulus of the laminated layer (3) at a temperature of 25°C was 0.1 MPa, and the refractive index for light at a wavelength of 589 nm was 1.48. The saturated moisture content of the laminated layer (3) was 1.0%.

[0243] <Preparation of the laminated layer (4)> (Preparation of adhesive sheet (4)) The adhesive sheet (4) was obtained in the same manner as the adhesive sheet (3), except that it was applied using an applicator to create a bonding layer (4) with a thickness of 15 μm after drying.

[0244] <Preparation of the laminated layer (5)> (Preparation of acrylic resin solution (3)) A reaction vessel equipped with a condenser, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 91 parts ethyl acetate, 43 parts 2-ethylhexyl acrylate, 55 parts butyl acrylate, and 2.0 parts 2-hydroxyethyl acrylate. The internal temperature was raised to 55°C while replacing the air in the apparatus with nitrogen gas to eliminate oxygen. Subsequently, the entirety of a solution prepared by dissolving 0.14 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was added. After adding the polymerization initiator, the temperature was maintained at this level for 1 hour. Then, while maintaining the internal temperature at 54-56°C, ethyl acetate was continuously added to the reaction vessel. When the concentration of the (meth)acrylic resin reached 35% by mass, the addition of ethyl acetate was stopped, and the temperature was maintained at this level for another 10 hours from the start of ethyl acetate addition. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, and acrylic resin solution (3) was prepared. The obtained acrylic resin had a weight-average molecular weight (Mw) of 1.1 million and a molecular weight distribution (Mw / Mn) of 4.8. Mw and Mn were measured using "TSKgel GMH" manufactured by Tosoh Corporation as the column in the GPC instrument. HR Two "-H(S)" units were connected in series, tetrahydrofuran was used as the eluate, and measurements were taken using standard polystyrene equivalents under the following conditions: sample concentration of 2 mg / mL, sample introduction volume of 100 μL, temperature of 40°C, and flow rate of 1 mL / min.

[0245] (Preparation of the adhesive layer forming composition (3)) To 100 parts of the solid content of the acrylic resin solution (3) obtained above, 0.3 parts on an active ingredient basis of a crosslinking agent (manufactured by Tosoh Corporation: trade name "Coronate L" (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass)) and 0.25 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added, and then ethyl acetate was added to bring the solid content concentration to 15% to obtain a composition (3) for forming an adhesive layer.

[0246] (Preparation of adhesive sheet (5)) The adhesive layer-forming composition (3) prepared above was applied using an applicator to the release-treated surface of a separator film made of polyethylene terephthalate film with a release treatment [POGW-502190 obtained from Lintec Corporation] to a thickness of 25 μm after drying, and dried at 100°C for 1 minute to produce a laminated layer (5). Next, the laminated layer (5) was laminated to the release-treated surface of a separator film made of polyethylene terephthalate film with a release treatment on the opposite side of the separator film [PLR-381031 obtained from Lintec Corporation] to produce an adhesive sheet (5) consisting of separator film 1 / laminated layer (5) / separator film 2. The storage modulus of the laminated layer (5) at a temperature of 25°C was 0.06 MPa. The saturated moisture content of the laminated layer (5) was 0.5%.

[0247] <Creation of the laminated layer (6)> (Preparation of acrylic resin solution (4)) A reaction vessel equipped with a condenser, nitrogen inlet tube, thermometer, and stirrer was charged with a mixed solution of 81.8 parts ethyl acetate, 98.0 parts butyl acrylate, and 2.0 parts acrylic acid. The internal temperature was raised to 55°C while replacing the air in the apparatus with nitrogen gas to eliminate oxygen. Subsequently, the entirety of a solution prepared by dissolving 0.14 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was added. After adding the polymerization initiator, the temperature was maintained at this level for 1 hour. Then, while maintaining the internal temperature at 54-56°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts / hr. When the concentration of the (meth)acrylic resin reached 35% by mass, the addition of ethyl acetate was stopped, and the temperature was maintained at this level for another 12 hours from the start of ethyl acetate addition. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by mass, and acrylic resin solution (4) was prepared. The obtained acrylic resin had a weight-average molecular weight (Mw) of 1.8 million and a molecular weight distribution (Mw / Mn) of 4.2. Mw and Mn were measured using "TSKgel GMH" manufactured by Tosoh Corporation as the column in the GPC instrument. HRTwo "-H(S)" were connected in series and arranged, and tetrahydrofuran was used as the eluent. The measurement was carried out in terms of standard polystyrene conversion under the conditions of a sample concentration of 2 mg / mL, a sample introduction volume of 100 μL, a temperature of 40 °C, and a flow rate of 1 mL / min.

[0248] (Preparation of the composition (4) for forming the adhesive layer) Based on 80 parts of the solid content of the acrylic resin solution (4) obtained above, 20 parts (solid content) of a bifunctional acrylate (obtained from Shin-Nakamura Chemical Co., Ltd.; product number "A-DOG"), 3.0 parts of a crosslinking agent (manufactured by Tosoh Corporation: trade name "Coronate L" (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 photoinitiator (manufactured by Ciba Specialty Chemicals: trade name "Irgacure 500"), and 0.5 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added. Further, ethyl acetate was added so that the solid content concentration became 13% to obtain the composition (4) for forming the adhesive layer.

[0249] (Preparation of the adhesive sheet (6)) The composition (4) for forming the adhesive layer prepared above was applied to the release-treated surface of a separate film made of a polyethylene terephthalate film with a release treatment (obtained from Lintec Corporation's "PLR-382150") using an applicator so that the dried thickness became 25 μm, and dried at 100 °C for 1 minute to produce the bonding layer (6). Next, the surface of the obtained bonding layer (6) opposite to the separator film was bonded to the release-treated surface of a separate film made of a polyethylene terephthalate film with a release treatment (obtained from Lintec Corporation's "PLZ-381130"). Subsequently, ultraviolet rays were irradiated under the following conditions to produce an adhesive sheet (6) composed of separator film 1 / bonding layer (6) / separator film 2. The storage elastic modulus of the bonding layer (6) at 25 °C was 0.8 MPa. The saturated moisture content of the bonding layer (6) was 0.8%. <UV irradiation conditions> ·Using a D valve of the Fusion UV lamp system (manufactured by Fusion UV Systems) • Total luminous intensity: 1500 mJ / cm² 2

[0250] (Fabrication of linear polarizers) A polyvinyl alcohol film with 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 stretching ratio of 4.5 times on a hot roll, and while maintaining tension, was immersed for 60 seconds in a 28°C staining bath containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water. Next, the polarizer was immersed for 110 seconds in a 64°C 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. Then, it was immersed for 30 seconds in a 67°C 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. After that, it was washed with pure water at 10°C and dried to obtain a linear polarizer. The thickness of the polarizer was 8 μm and the boron content was 4.3% by mass.

[0251] <Fabrication of polarizing plate (1)> The aqueous adhesive composition obtained above was applied to one side of the linear polarizer obtained above, and a cyclic polyolefin resin film with a hard coat (HC) layer (COP film) was laminated onto it. A TAC film was laminated to the other side of the polarizer via water, and after drying at 80°C for 5 minutes, the TAC film was peeled off to obtain a polarizer having a protective film on one side of the linear polarizer. The layer structure of the polarizer is COP film / aqueous adhesive layer / linear polarizer.

[0252] <Fabrication of the first and second liquid crystal phase difference layers> (Preparation of the 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 heated at 100°C for 1 hour to obtain an oriented polymer composition (1).

[0253] (Preparation of photo-oriented polymer composition (1)) A photo-oriented material with the following structure (weight-average molecular weight: 50,000, m:n=50:50) was manufactured according to the method described in Japanese Patent Application Publication No. 2021-196514. Two parts of the photo-oriented material and 98 parts of propylene glycol monomethyl ether (PGME, solvent) were mixed as components, and the resulting mixture was stirred at 80°C for 1 hour to prepare a photo-oriented polymer composition (1). Photoalignable materials: [ka]

[0254] (Manufacturing of polymerizable liquid crystal compounds) Polymerizable liquid crystal compounds (A1) and (A2), having the structures shown below, were prepared, respectively. Polymerizable liquid crystal compounds (A1) and (A2) were prepared in the same manner as described in Japanese Patent Application Publication No. 2010-244038.

[0255] Polymerizable liquid crystal compound (A1): [ka]

[0256] Polymerizable liquid crystal compound (A2): [ka]

[0257] (Preparation of liquid crystal phase difference layer formation composition (Y1)) Polymerizable liquid crystal compound (A1) and 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 the leveling agent "Megafac F-556" (manufactured by DIC Corporation), the photopolymerization initiator "Omnirad907" (manufactured by IGM Resin BV Corporation), and an ionic compound (B) were added. Furthermore, propylene glycol monomethyl ether acetate (PEGMEA) was added, and this mixture was stirred at a temperature of 80°C for 1 hour to prepare a liquid crystal phase difference layer forming composition (Y1). The amounts of each component added are shown in Table 1 below.

[0258] [Table 1]

[0259] Ionic compounds (B): [ka]

[0260] (Preparation of liquid crystal phase difference layer formation composition (Y2)) The polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF Japan), the leveling agent "BYK-361N" (manufactured by BYK-Chemie), and the photopolymerization initiator "Omnirad907" (manufactured by IGM Resin BV) were added. Furthermore, propylene glycol monomethyl ether acetate (PEGMEA) was added, and this mixture was stirred at 80°C for 1 hour to prepare a liquid crystal phase difference layer forming composition (Y2). The amounts of each component added are shown in Table 2 below.

[0261] [Table 2]

[0262] Polymerizable liquid crystal compound LC242: [ka]

[0263] <Fabrication of the first liquid crystal phase difference layer film (Z1)> Rectangular cut triacetylcellulose film (TAC) (thickness 40 μm, temperature 40°C, relative humidity 90% RH, moisture permeability 950 g / m²) 2An oriented polymer composition (1) was applied to the TAC (Turn Aqueous Control Center) for 24 hours to form an oriented polymer film with a thickness of 100 nm after heating and drying. The surface of the obtained oriented polymer film was rubbed from the longitudinal direction of the TAC at an angle of -15° to the slow axis of the first liquid phase difference layer (X1) to be formed below, and then a liquid phase difference layer forming composition (Y1) was applied using a bar coater. The obtained coated film was dried at 100°C for 1 minute and then cooled to room temperature to obtain a dried film. Next, a high-pressure mercury lamp (UniCure VB-15201BY-A, manufactured by Ushio Inc.) was used to expose the film to a nitrogen atmosphere at an exposure dose of 1000 mJ / cm². 2 By irradiating the dried film with ultraviolet light (based on 365 nm), a first liquid crystal phase difference layer (X1) was formed in which the polymerizable liquid crystal compound was cured in a state where it was oriented horizontally with respect to the substrate plane, and a phase difference film (Z1) consisting of TAC / alignment film / first liquid crystal phase difference layer (X1) (horizontally oriented liquid crystal cured film) was obtained. The thickness of the obtained first liquid crystal phase difference layer (X1) was measured with a laser microscope and found to be 1.8 μm. The in-plane phase difference value was measured using a KOBRA-WR manufactured by Oji Instruments Co., Ltd. As a result, the in-plane phase difference value at a wavelength of 550 nm was Re(550) = 236 nm, the in-plane phase difference value at a wavelength of 450 nm was Re(450) = 256 nm, and the in-plane phase difference value at a wavelength of 650 nm was Re(650) = 231 nm. Note that the phase difference value of TAC at a wavelength of 550 nm is approximately 0, so it does not affect the optical properties. The orientation angle was -15° with respect to the longitudinal direction of the TAC. The first liquid crystal phase difference layer (X1) was a positive wavelength dispersion λ / 2 layer. The in-plane average refractive index of the first liquid crystal phase difference layer (X1) was 1.54.

[0264] <Fabrication of the second liquid crystal phase difference layer film (Z2)> Rectangular cut triacetylcellulose film (TAC) (thickness 40 μm, temperature 40°C, relative humidity 90% RH, moisture permeability 950 g / m²) 2A photo-aligning polymer composition (1) was applied to the TAC (24hr). The resulting coating was dried at 120°C for 2 minutes, then cooled to room temperature to form a dry film. Furthermore, using a UV irradiation device, polarized ultraviolet light of 100 mJ (based on 313 nm) was continuously irradiated so that the slow axis of the resulting second liquid crystal phase difference layer (X2) was 75° relative to the longitudinal direction of the TAC, forming a 100 nm photo-alignment film. On this, a liquid crystal phase difference layer forming composition (Y2) was applied using a bar coater. The resulting coating was dried at 100°C for 1 minute, then cooled to room temperature to obtain a dry film. Next, using a high-pressure mercury lamp, exposure at 1000 mJ / cm² was applied under a nitrogen atmosphere. 2 By continuously irradiating the dried film with ultraviolet light (based on 365 nm), a second liquid crystal phase difference layer (X2) was formed in which the polymerizable liquid crystal compound was cured in a state where it was oriented horizontally with respect to the substrate plane, and a phase difference film (Z2) consisting of TAC / alignment film / second liquid crystal phase difference layer (X2) (horizontally oriented liquid crystal cured film) was obtained. The thickness of the obtained second liquid crystal phase difference layer (X2) was measured with a laser microscope and found to be 1.0 μm. The in-plane phase difference value was measured using a KOBRA-WR manufactured by Oji Instruments Co., Ltd. As a result, the in-plane phase difference value at a wavelength of 550 nm was Re(550) = 115 nm, the in-plane phase difference value at a wavelength of 450 nm was Re(450) = 130 nm, and the in-plane phase difference value at a wavelength of 650 nm was Re(650) = 111 nm. Note that the phase difference value of TAC at a wavelength of 550 nm is approximately 0, so it does not affect the optical properties. The orientation angle was 75° with respect to the longitudinal direction of the TAC. The second liquid crystal phase difference layer (X2) was a positive wavelength dispersion λ / 4 layer. The in-plane mean refractive index of the second liquid crystal phase difference layer (X2) was 1.54.

[0265] <Fabrication of Phase Difference Layered Stack 1> The first liquid crystal phase difference layer (X1) of the first liquid crystal phase difference layer film (Z1) and the second liquid crystal phase difference layer (X2) of the second liquid crystal phase difference layer film (Z2) are each supplied with 28 kJ / m³ 2Corona treatment was performed under the specified conditions. A coating of the aqueous adhesive composition obtained above was formed on the first liquid crystal phase difference layer (X1) of the first liquid crystal phase difference layer film (Z1) so that the thickness of the aqueous adhesive layer after drying was an arbitrary thickness (0.01 to 0.25 μm). Subsequently, the second liquid crystal phase difference layer (X2) of the second liquid crystal phase difference layer film (Z2) was laminated on the coating of the aqueous adhesive composition, and dried for 3 minutes in an atmospheric atmosphere at a temperature of 90°C to obtain a phase difference layer laminate 1 in which TAC / alignment film / first liquid crystal phase difference layer (X1) / aqueous adhesive layer / second liquid crystal phase difference layer (X2) / alignment film / TAC was laminated in this order. The phase difference film (Z1) and the phase difference film (Z2) were laminated so that their longitudinal directions were aligned. Viewed from the phase difference film (Z2) side in the thickness direction, the slow phase axis of the first liquid crystal phase difference layer (X1) of the phase difference film (Z1) is tilted at 15° with respect to the longitudinal direction of the phase difference laminate 1, and the slow phase axis of the second liquid crystal phase difference layer (X2) of the phase difference film (Z2) is tilted at 75°, resulting in an angle of 60° between the slow phase axes.

[0266] (Examples 1-3, Comparative Examples 2,3) The separator film 1 is peeled off from the adhesive sheet (1), and 28 kJ / m² is applied to the surface of the adhesive layer (1). 2 Corona treatment was performed under the following conditions. Then, the laminated layer (1) side was bonded to the polarizer surface of the polarizer plate (1) to obtain a polarizer plate (1) with laminated layer (1). The separator film 2 of the obtained polarizer plate (1) with laminated layer (1) was peeled off, and 28 kJ / m was applied to the other side of the laminated layer (1). 2 Corona treatment was performed under the following conditions. After drying, the thickness of the water-based adhesive layer was 0.04, 0.10, 0.15, 0.01, and 0.25 μm in order from Example 1. After peeling off the TAC / alignment film on the first liquid crystal phase difference layer (X1) side of each phase difference layer laminate 1, 28 kJ / m³ was applied to the first liquid crystal phase difference layer (X1). 2Corona treatment was performed under the following conditions. The first liquid crystal phase difference layer (X1) of the phase difference layer laminate 1 and the laminated layer (1) surface of the polarizing plate (1) with the previously obtained laminated layer (1) were bonded together such that the absorption axis of the polarizing plate (1) was 90° with respect to the longitudinal direction of the phase difference layer (1), that is, the transmission axis of the polarizing plate coincided with the longitudinal direction of the phase difference layer laminate. The alignment film / TAC on the second liquid crystal phase difference layer (X2) side of the resulting laminate was peeled off, the separator film 1 was peeled off from the adhesive sheet (3), and the laminated layer (3) side was bonded to the second liquid crystal phase difference layer (X2), thereby obtaining an optical laminate in which the COP film / water-based adhesive layer / linear polarizer / laminated layer (1) / first liquid crystal phase difference layer (X1) / water-based adhesive layer / second liquid crystal phase difference layer (X2) / laminated layer (3) / separator film 2 were laminated in this order. Table 1 shows the details of the thickness of the water-based adhesive layer after drying, formed on the TAC surface of the phase difference layer (1) and the polarizing plate (1) in each example.

[0267] (Example 4) An optical laminate was obtained in the same manner as in Example 1, except that adhesive sheet (2) was used instead of adhesive sheet (1).

[0268] (Example 5) An optical laminate was obtained in the same manner as in Example 1, except that adhesive sheet (6) was used instead of adhesive sheet (1).

[0269] (Comparative Example 1) The TAC / alignment film on the first liquid crystal phase difference layer (X1) side of the phase difference layer laminate 1, which was fabricated so that the thickness of the water-based adhesive layer after drying was 0.04 μm, was peeled off, and 28 kJ / m³ was applied to the first liquid crystal phase difference layer (X1) surface. 2Corona treatment was performed under the following conditions. A water-based adhesive coating was formed on the first liquid crystal phase difference layer (X1) so that the thickness of the water-based adhesive layer after drying was 0.04 μm. Subsequently, the linear polarizer (1) side of the polarizing plate (1) was laminated onto the water-based adhesive coating so that its absorption axis was 90° with respect to the longitudinal direction of the phase difference layer 1, that is, so that the transmission axis of the polarizing plate coincided with the longitudinal direction of the phase difference layer laminate, and it was dried for 3 minutes in an atmospheric atmosphere at a temperature of 90°C. The alignment film / TAC on the second liquid crystal phase difference layer (X2) side of the obtained polarizing plate (1) attached phase difference layer laminate 1 was peeled off, the separator film 1 was peeled off from the adhesive sheet (3), and the side with the bonding layer (3) was bonded to the second liquid crystal phase difference layer (X2), thereby obtaining an optical laminate in which the COP film / water-based adhesive layer / linear polarizer / water-based adhesive layer / first liquid crystal phase difference layer (X1) / water-based adhesive layer / second liquid crystal phase difference layer (X2) / bonding layer (3) / separator film 2 were laminated in this order.

[0270] (Comparative Example 4) An optical laminate was obtained in the same manner as in Example 1, except that adhesive sheet (3) was used instead of adhesive sheet (1).

[0271] (Comparative Example 5) An optical laminate was obtained in the same manner as in Example 1, except that adhesive sheet (4) was used instead of adhesive sheet (1).

[0272] (Comparative Example 6) An optical laminate was obtained in the same manner as in Example 1, except that adhesive sheet (5) was used instead of adhesive sheet (1).

[0273] (Comparative Example 7) An optical laminate was obtained in the same manner as in Example 1, except that the phase difference layer laminate 2 shown below was used instead of the phase difference layer laminate 1. <Phase difference layered laminate 2> (Preparation of adhesive A (active energy ray curing adhesive)) The following components were combined and mixed, then degassed to prepare adhesive A as an active energy ray curing adhesive. [Cationically polymerizable compounds] ·3',4'-Epoxycyclohexylmethyl3,4-Epoxycyclohexanecarb Silate (product name: CEL2021P, manufactured by Daicel Corporation): 70 parts by mass • Neopentyl glycol diglycidyl ether (product name: EX-211, Nagase Chemte) (Manufactured by KS Corporation): 20 parts by mass • 2-Ethylhexylglycidyl ether (Product name: EX-121, Nagase ChemteX) (Manufactured by [Company Name]): 10 parts by mass [Photocationic polymerization initiator] • Cationic polymerization initiator (Product name: CPI-100P 50% solution propylene carbonate solution, manufactured by Sunapro Co., Ltd.) : 4.5 parts by mass (actual solid content 2.25 parts by mass) [Photosensitizer] • 1,4-Diethoxynaphthalene: 2 parts by mass (Lamination of phase difference layered laminate 2) The first liquid crystal phase difference layer (X1) of the first liquid crystal phase difference layer film (Z1) and the second liquid crystal phase difference layer (X2) of the second liquid crystal phase difference layer film (Z2) are each supplied with 28 kJ / m³ 2 The coronavirus treatment was performed under these conditions. The liquid crystal phase difference layers of the first liquid crystal phase difference layer film (Z1) and the second liquid crystal phase difference layer film (Z2) were bonded together using a laminator via adhesive A to obtain a laminate. From the second liquid crystal phase difference layer film (Z2) side of the obtained laminate, an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to apply an integrated light intensity of 300 mJ / cm². 2 Adhesive A was cured by UVB irradiation to form adhesive layer A (thickness: 2 μm).

[0274] <Phase difference value of phase difference laminate> In each example and comparative example, the Re(450) and Re(550) of the phase difference layer laminate were measured. The Re(450) was 112 nm, and the Re(450) / Re(550) was 0.80.

[0275] <Rating> (Evaluation of unevenness in optical laminates) The optical laminate was cut to a size of 150 mm x 150 mm. The cut optical laminate was attached to an aluminum reflector to obtain a test specimen for observing interference unevenness. The test specimen for observing interference unevenness was placed on a stand so that it made an angle of 45° with respect to the floor, with the floor being 0°. Linear polarizers were placed between the three-wavelength fluorescent lamp (as the light source) and the test specimen for observing interference unevenness, and between the test specimen and the observer, so that their transmission axes were perpendicular to each other (crossed nicols). The light from the three-wavelength fluorescent lamp was shone onto the test specimen for observing interference unevenness from the 90° direction (above the test specimen). When the observer observed the test specimen from the 0° direction, the test specimen was rotated so that it could be observed and evaluated from various directions. AA: No interference unevenness is visible at all. A: Interference unevenness is hardly visible. B: Interference unevenness is visible, but it is weaker than C. C: Interference irregularities are visible. D: Uneven adhesion is visible.

[0276] (Durability evaluation of optical laminates: Iodine discoloration) The separator film 2 was peeled off from the optical laminate, and the optical laminate was bonded to an organic EL display element via the exposed bonding layer (3) to fabricate an organic EL display device. The color and appearance of the optical laminate were observed after the organic EL display device was stored for 19 hours under conditions of 85°C and 85% RH. However, color loss at the edges was evaluated only for the edges parallel to the absorption axis direction of the polarizer. A: Discoloration at the edges (less than 55 μm) B: Discoloration at the edges (55μm or more and less than 60μm) C: Discoloration at the edges (60μm or more and less than 70μm) D: Discoloration at the edges (70μm or more)

[0277] (End face evaluation by hole punching) A 10mm diameter hole was punched into the optical laminate using a hole punching machine. The edge surfaces around the holes were observed under a microscope to evaluate the edge surface quality. A: There is almost no glue chipping on the edges around the holes. B: Slight glue chipping is visible on a portion of the edge around the hole. C: Significant glue chipping is visible on a portion of the edge around the hole. D: Significant glue chipping is visible across the entire edge surface around the hole. A lower storage modulus of the adhesive layer makes it more prone to chipping, and when the storage modulus of the adhesive layer is the same, a thicker adhesive layer tends to be more prone to chipping.

[0278] <Measurement of the saturated moisture content of adhesive sheets> The adhesive layers of the adhesive sheets (1) to (6) prepared as described above were stored under the following storage conditions (1), and then under the following storage conditions (2). The mass of the adhesive layer after each storage condition was measured using the IGA Sorp moisture absorption / desorption analyzer (manufactured by Hiden Isochema), and the saturated moisture content of the adhesive layer at a temperature of 25°C and a relative humidity of 80% RH was determined based on the following formula. The results are shown in Table 3. Storage conditions (1): Temperature 25°C, dry atmosphere, storage time 24 hours Storage conditions (2): Temperature 25°C, relative humidity 80%RH, storage time 15hr Saturated moisture content [%] = [(Mass after storage condition (2)) - (Mass after storage condition (1))] (Mass after storage conditions (1))

[0279] <Measurement of Storage Modulus> The storage modulus of the adhesive layer at 25°C was measured using a viscoelasticity measuring device (MCR-301, Anton Paar). The adhesive layer was removed from the adhesive sheet, stacked in layers to a thickness of 1 mm, and cut into 8 mm diameter pieces. The stage / adhesive layer / measuring system was set up in this order in the device, and measurements were taken in the temperature range of -22°C to 85°C under conditions of frequency 1.0 Hz, deformation 1%, load 1 N, and heating rate 10°C / min to determine the storage modulus of the adhesive layer at 25°C.

[0280] Table 3 shows the storage modulus, saturated moisture content, and thickness of the laminated layers (1) to (6). Tables 4 and 5 show the conditions and results.

[0281] [Table 3]

[0282] [Table 4]

[0283] [Table 5] [Explanation of Symbols]

[0284] 30...First liquid crystal phase difference layer, 40...Adhesive layer, 50...Second liquid crystal phase difference layer, 150...Adhesive layer, 180...First protective layer, 220...Linear polarizer, 300...Phase difference layer laminate, 400...Optical laminate (circular polarizer).

Claims

1. The first protective layer, linear polarizer, adhesive layer, and phase difference layer laminate are provided in this order. The adhesive layer has a storage modulus of 0.2 to 1.0 MPa at 25°C and a thickness of 2 to 25 μm. The phase difference layer laminate is an optical laminate having a first liquid crystal phase difference layer, an adhesive layer having a thickness of 20 to 200 nm, and a second liquid crystal phase difference layer, in this order from the adhesive layer side.

2. The optical laminate according to claim 1, wherein the parameter X, which is the product of the saturated moisture content (mass%) and thickness (μm) of the adhesive layer at 25°C and 80% relative humidity, is between 3 and 23.

3. The optical laminate according to claim 1 or 2, wherein the adhesive layer has a thickness of 2 to 15 μm.

4. The optical laminate according to claim 1 or 2, wherein the adhesive layer has a thickness of 2 to 10 μm.

5. The optical laminate according to claim 1 or 2, wherein the adhesive layer is a water-based adhesive layer.

6. The optical laminate according to claim 1 or 2, wherein the adhesive layer has a thickness of 25 to 150 nm.

7. The optical laminate according to claim 1 or 2, wherein when the in-plane phase difference value of the phase difference layer laminate with respect to light of wavelength λ nm is Re(λ), the relationship between the following equations (1) and (2) is satisfied. 80 nm ≤ Re(450) ≤ 130 nm (1) Re(450) / Re(550)≦1.00 (2)

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