Optically anisotropic layered body and circularly polarizing plate comprising same

Abstract

To provide an optically anisotropic laminate and a circularly polarizing plate which do not cause white turbidity unevenness even when observed under strong light.SOLUTION: An optically anisotropic layered body comprising a first liquid crystal retardation film in which a polymerizable liquid crystal compound is oriented, a stickable-curable adhesive layer 1, and a second liquid crystal retardation film in which a polymerizable liquid crystal compound is oriented adjacently in this order, wherein an angle formed by a liquid crystal molecule orientation direction of a surface of the first liquid crystal retardation film in contact with the stickable-curable adhesive layer 1 and a liquid crystal molecule orientation direction of a surface of the second liquid crystal retardation film in contact with the stickable-curable adhesive layer 1 is 0 ± 10 °, and a thickness of each of the first liquid crystal retardation film and the second liquid crystal retardation film is 0.1 to 3 μm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an optically anisotropic laminate and a circularly polarizing plate including the optically anisotropic laminate. [Background technology]

[0002] Flat panel display devices use components including various optical films such as polarizing plates and retardation plates. Known examples of such optical films include optical films prepared by applying a composition containing a polymerizable liquid crystal compound to a substrate and polymerizing the polymerizable liquid crystal compound in an aligned state. For example, Patent Document 1 discloses a circular polarizing plate in which a first retardation layer and a second retardation layer, each of which contains one or more aligned polymerizable liquid crystal compounds, are laminated such that the alignment directions of the liquid crystal molecules form a specific angle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 003416 Summary of the Invention [Problem to be solved by the invention]

[0004] The circular polarizing plate disclosed in Patent Document 1 achieves a neutral reflected color even when used under strong light by laminating two retardation layers at a specific angle. However, the present inventors have discovered that when such a circular polarizing plate is observed under strong light, slight cloudy unevenness may be visible. Such cloudy unevenness not only causes an appearance defect in the optical film, but can also cause reduced visibility when used in the display of various image display devices.

[0005] An object of the present invention is to provide an optically anisotropic laminate and a circularly polarizing plate that do not develop cloudy unevenness even when observed under strong light. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, the present invention includes the following aspects. [1] An optically anisotropic laminate comprising a first liquid crystal retardation film in which a polymerizable liquid crystal compound is aligned, a pressure-sensitive adhesive layer 1, and a second liquid crystal retardation film in which a polymerizable liquid crystal compound is aligned, arranged adjacent to each other in this order, an angle formed by a liquid crystal molecular alignment direction of a first liquid crystal retardation film surface in contact with the adhesive layer 1 and a liquid crystal molecular alignment direction of a second liquid crystal retardation film surface in contact with the adhesive layer 1 is 0±10°; An optically anisotropic laminate, wherein the thickness of each of the first liquid crystal retardation film and the second liquid crystal retardation film is 0.1 to 3 μm. [2] The optically anisotropic laminate according to [1] above, wherein at least one of the first liquid crystal retardation film and the second liquid crystal retardation film is aligned by a photoalignment film. [3] The optically anisotropic laminate according to [1] or [2] above, wherein the adhesive layer 1 is an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound. [4] The optically anisotropic laminate according to any one of the above [1] to [3], wherein the adhesive layer 1 has a thickness of 0.1 to 3 μm. [5] The optically anisotropic laminate according to any one of the above [1] to [4], wherein the adhesive layer 1 has an in-plane average refractive index of 1.50 to 1.65 at a wavelength of 589 nm. [6] The optically anisotropic laminate according to any one of the above [1] to [5], further comprising a third liquid crystal retardation film on the surface of the second liquid crystal retardation film opposite to the adhesive layer 1 via an adhesive layer 2. [7] The optically anisotropic laminate according to [6] above, wherein the adhesive layer 2 is an adhesive layer. [8] A circularly polarizing plate comprising a polarizing plate on the side opposite to the adhesive layer 1 of the first liquid crystal retardation film of the optically anisotropic laminate according to any one of [1] to [7], via an adhesive layer 3. [9] The circularly polarizing plate according to the above [8], wherein the adhesive layer 3 is an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound.

[10] The circularly polarizing plate according to the above [8] or [9], wherein the thickness of the adhesive layer 3 is 0.1 to 3 μm.

[11] The circularly polarizing plate according to any one of the above [8] to

[10] , wherein the adhesive layer 3 has an average in-plane refractive index at a wavelength of 589 nm of 1.45 to 1.60.

[12] The circularly polarizing plate according to any one of [8] to

[11] above, further comprising a protective film on the pressure-sensitive adhesive layer 3 side of the polarizing plate, the protective film having an in-plane refractive index of 1.45 to 1.55.

[13] The circularly polarizing plate according to any one of the above [8] to

[12] , wherein the angle formed by the slow axis of the first liquid crystal retardation film with respect to the transmission axis of the polarizing plate is 15±5°. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an optically anisotropic laminate and a circularly polarizing plate that do not develop cloudy unevenness even when observed under strong light. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0009] <Optical anisotropic laminate> The optically anisotropic laminate of the present invention comprises a first liquid crystal retardation film formed by aligning a polymerizable liquid crystal compound, a pressure-sensitive adhesive layer 1, and a second liquid crystal retardation film formed by aligning a polymerizable liquid crystal compound, arranged adjacent to each other in this order. In the optically anisotropic laminate of the present invention, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film surface in contact with the pressure-sensitive adhesive layer 1 and the liquid crystal molecular alignment direction of the second liquid crystal retardation film surface in contact with the pressure-sensitive adhesive layer 1 is 0±10°. Since the liquid crystal molecular alignment directions of the film surfaces of the first liquid crystal retardation film and the second liquid crystal retardation film in contact with the pressure-sensitive adhesive layer 1 are the same or nearly the same, the first liquid crystal retardation film and the second liquid crystal retardation film can be combined to obtain a desired in-plane retardation value and can suppress cloudy unevenness. In the present invention, the "liquid crystal molecular alignment direction on the liquid crystal retardation film surface" refers to the direction of liquid crystal molecular alignment observed on the film surface that is the outermost surface of each retardation film in contact with the adhesive layer 1. The liquid crystal molecular alignment direction can be controlled, for example, by the alignment direction imparted to the alignment film. The liquid crystal molecular alignment direction can be measured, for example, using a retardation measurement device, and generally, the direction is parallel or perpendicular to the slow axis. Furthermore, the liquid crystal molecular alignment on the adhesive layer 1 side of the helically aligned liquid crystal retardation film can be measured, for example, by analyzing the results of measuring the angle dependence of polarized ATR-IR or polarized reflectance. In detail, it can be determined according to the method described in the Examples below.

[0010] In one embodiment of the present invention, the angle formed by the liquid crystal molecular alignment direction of the first liquid crystal retardation film surface in contact with the adhesive layer 1 and the liquid crystal molecular alignment direction of the second liquid crystal retardation film surface in contact with the adhesive layer 1 is 0±10°, preferably 0±7°, more preferably 0±5°, and still more preferably 0±3°. When the first liquid crystal retardation film and the second liquid crystal retardation film are laminated at an angle within the above range, the above effect can be further enhanced.

[0011] The thickness of the first liquid crystal retardation film and the second liquid crystal retardation film is each 0.1 to 3 μm. When the thickness of the first liquid crystal retardation film and the second liquid crystal retardation film is within the above range, an optically anisotropic laminate without opaque unevenness can be obtained when observed under strong light. This is thought to be because, although not necessarily limited to the following reasons, in a liquid crystal retardation film whose thickness is controlled within the above range, the alignment control force is sufficiently exerted, enhancing the alignment of the polymerizable liquid crystal compound constituting the liquid crystal retardation film and reducing the occurrence of alignment defects. To further enhance the above effects, in the present invention, the thickness of the first liquid crystal retardation film and the second liquid crystal retardation film is each more preferably 0.1 to 2.5 μm, even more preferably 0.3 to 2.5 μm, and particularly preferably 0.5 to 2 μm. The thickness of each liquid crystal retardation film can be measured using a laser microscope, a film thickness meter, or the like. The same applies to the measurement of the thickness of each layer, such as the adhesive layer and protective film, constituting the optically anisotropic laminate or circular polarizer.

[0012] In the present invention, the in-plane average refractive index at a wavelength of 589 nm of the first liquid crystal retardation film and the second liquid crystal retardation film can be appropriately determined depending on the in-plane average refractive index of the adhesive layer 1 adjacent thereto, the optical properties required of the optically anisotropic laminate, the configuration of the polarizing plate laminated with the optically anisotropic laminate, etc. In one embodiment of the present invention, for example, it is preferably 1.45 to 1.65, more preferably 1.50 to 1.60. When the in-plane average refractive indexes of the first and second liquid crystal retardation films are each within the above ranges, it is easy to control the refractive index difference between each layer in relation to the adhesive layer 1 located therebetween, and light reflection at the interface between the liquid crystal retardation film and the adhesive layer 1 can be suppressed.

[0013] In this specification, the in-plane average refractive index of the liquid crystal retardation film is a refractive index at a wavelength of 589 nm, and the in-plane average refractive index (589 nm) in the state of the liquid crystal retardation film can be measured using an ellipsometer M-220 manufactured by JASCO Corporation or the like. Specifically, it can be measured, for example, according to the method described in the examples below. The in-plane average refractive index of the pressure-sensitive adhesive layer 1, protective film, etc. described below can also be measured in the same manner.

[0014] In the present invention, the in-plane average refractive index at a wavelength of 589 nm of the adhesive layer 1 located between the first liquid crystal retardation film and the second liquid crystal retardation film can be appropriately determined depending on the in-plane average refractive indexes of the adjacent first and second liquid crystal retardation films, the optical properties required of the optically anisotropic laminate, the configuration of the polarizing plate laminated with the optically anisotropic laminate, etc., but is preferably 1.50 to 1.65. When the in-plane average refractive index of the adhesive layer 1 is within the above range, it becomes easy to control the refractive index difference between the adhesive layer 1 and the first liquid crystal retardation film and the refractive index difference between the adhesive layer 1 and the second liquid crystal retardation film. By reducing these refractive index differences, light reflection in the optically anisotropic laminate can be suppressed, and when the laminate is incorporated into an image display device and black display is performed, reflection of external light between the layers can be effectively suppressed. From this viewpoint, the average in-plane refractive index at a wavelength of 589 nm of the pressure-sensitive adhesive layer 1 is more preferably 1.52 or more, even more preferably 1.55 or more, for example, 1.57 or more, and is more preferably 1.63 or less, even more preferably 1.60 or less.

[0015] The thickness of the adhesive layer 1 is preferably 0.1 to 3 μm. The thickness of the adhesive layer 1 can be a factor affecting interference unevenness in an optically anisotropic laminate. For example, the thicker the adhesive layer 1, the greater the effect of suppressing interference unevenness in a laminate consisting of a first liquid crystal retardation film, the adhesive layer 1, and a second liquid crystal retardation film. Therefore, a thicker adhesive layer 1 may be advantageous from the perspective of interference unevenness. However, in the present invention, for example, by controlling the in-plane average refractive index of the adhesive layer 1 and the in-plane average refractive indexes of the first liquid crystal retardation film and the second liquid crystal retardation film within the above-mentioned ranges, an optically anisotropic laminate having an excellent effect of suppressing interference unevenness can be obtained even with a thin adhesive layer 1. Therefore, the thickness of the adhesive layer 1 is, for example, more preferably 0.1 to 2.5 μm, even more preferably 0.3 to 2.5 μm, and particularly preferably 0.5 to 2 μm.

[0016] In one embodiment of the present invention, the difference (absolute value difference: |n1-n2|) between the in-plane average refractive index of the adhesive layer 1 (hereinafter also referred to as "refractive index n1") and the in-plane average refractive index of the first liquid crystal retardation film (hereinafter also referred to as "refractive index n2") is preferably 0.12 or less, more preferably 0.10 or less, and may be, for example, 0.08 or less, 0.05 or less, or 0.03 or less. When the difference between the refractive index n1 of the adhesive layer 1 and the refractive index n2 of the first liquid crystal retardation film is equal to or less than the above-mentioned upper limit, an even greater effect of suppressing light reflection at the interface between these two layers can be expected. From the viewpoint of suppressing light reflection and obtaining an excellent reflection suppression effect when incorporated into a display device, the smaller the difference, the better, and ideally it is 0.

[0017] In one embodiment of the present invention, the difference (absolute value difference: |n1-n3|) between the in-plane average refractive index n1 of the adhesive layer 1 and the in-plane average refractive index of the second liquid crystal retardation film (hereinafter also referred to as "refractive index n3") is preferably 0.12 or less, more preferably 0.10 or less, and may be, for example, 0.08 or less, 0.05 or less, or 0.03 or less. When the difference between the refractive index n1 of the adhesive layer 1 and the refractive index n3 of the second liquid crystal retardation film is equal to or less than the above-mentioned upper limit, an even greater effect of suppressing light reflection at the interface between these two layers can be expected. From the viewpoint of suppressing light reflection and obtaining an excellent reflection suppression effect when incorporated into a display device, the smaller the difference, the better, and ideally it is 0.

[0018] In one embodiment of the present invention, it is preferable that the refractive index difference between the adhesive layer 1 and the first liquid crystal retardation film (hereinafter also referred to as "refractive index difference Δn1") and the refractive index difference between the adhesive layer 1 and the second liquid crystal retardation film (hereinafter also referred to as "refractive index difference Δn2") are both not more than the above-mentioned upper limits. When these refractive index differences are both not more than the above-mentioned upper limits, mutual interference between light reflection at the interface between the adhesive layer 1 and the first liquid crystal retardation film and light reflection at the interface between the adhesive layer 1 and the second liquid crystal retardation film is unlikely to occur, thereby improving the anti-reflection effect when incorporated into a display device. In one embodiment of the present invention, the difference between the refractive index difference Δn1 and the refractive index difference Δn2 (absolute value difference: |Δn1-Δn2|) is preferably not more than 0.05, more preferably not more than 0.03.

[0019] The refractive indexes n1, n2, and n3, as well as the difference therebetween, can be controlled by appropriately selecting the compositions of the first liquid crystal retardation film, the second liquid crystal retardation film, and the adhesive layer 1, particularly the types of compounds constituting each of these layers, their combinations, etc. In particular, by adjusting the refractive index of the adhesive layer 1, which does not have optical absorption anisotropy, to approximate the in-plane average refractive index of the first liquid crystal retardation film and the second liquid crystal retardation film, it is possible to effectively suppress light reflection occurring at the interface between the first liquid crystal retardation film and the adhesive layer 1 and the interface between the adhesive layer 1 and the second liquid crystal retardation film, while ensuring the high optical properties required of a retardation film.

[0020] In the present invention, the first liquid crystal retardation film and the second liquid crystal retardation film are each a liquid crystal cured film formed by aligning a polymerizable liquid crystal compound. The first liquid crystal retardation film and the second liquid crystal retardation film are not particularly limited in configuration, as long as they can be laminated so that the mutual alignment directions are within the above-mentioned specific angle range, and can be appropriately determined depending on the desired optical properties, etc. The first liquid crystal retardation film and the second liquid crystal retardation film may be, for example, a film formed by fixing a rod-shaped polymerizable liquid crystal compound oriented horizontally to the film surface, a film formed by fixing a discotic polymerizable liquid crystal compound oriented vertically to the film surface, or a film formed by fixing a rod-shaped polymerizable liquid crystal compound helically oriented along a helical axis extending in the thickness direction of the retardation film. The first liquid crystal retardation film and the second liquid crystal retardation film may be the same or different. The above-mentioned state "formed by fixing a polymerizable liquid crystal compound" means a state in which the alignment of the polymerizable liquid crystal compound is maintained. In this specification, when simply referring to a "liquid crystal retardation film", unless otherwise specified, the "liquid crystal retardation film" includes both the first liquid crystal retardation film and the second liquid crystal retardation film.

[0021] A film formed by fixing rod-shaped polymerizable liquid crystal compounds aligned horizontally relative to the film surface (hereinafter also referred to as a "horizontally aligned rod-shaped liquid crystal cured retardation film") is obtained by aligning the rod-shaped polymerizable liquid crystal compounds so that their long axes are parallel to the in-plane direction of the liquid crystal retardation film. Here, "parallel" does not require strict parallelism, but means that the angle between the long axis of the rod-shaped polymerizable liquid crystal compound and the in-plane direction of the liquid crystal retardation film is in the range of 0 to 10°.

[0022] When the first liquid crystal retardation film and / or the second liquid crystal retardation film are horizontally aligned rod-shaped liquid crystal cured retardation films, they are each represented by the following formula (1): 100 nm ≦ Re(550) ≦ 180 nm (1) (wherein Re(λ) represents the in-plane retardation value of the retardation film at a wavelength of λ nm) The film may satisfy the following formula. When the in-plane retardation Re(550) of the horizontally aligned rod-like liquid crystal cured retardation film is within the range of formula (1), the retardation film functions as a quarter-wave plate, and when a circular polarizer including the retardation film is applied to an organic EL display device or the like, the effect of improving the front reflection hue (the effect of suppressing coloration) is likely to be enhanced. A more preferred range for the in-plane retardation value is 120 nm≦Re(550)≦170 nm, and even more preferably 130 nm≦Re(550)≦150 nm.

[0023] The polymerizable liquid crystal compound forming the horizontally aligned rod-shaped liquid crystal cured retardation film can be appropriately selected from polymerizable liquid crystal compounds known in the art.Specific examples include the compounds described in JP-A-2010-31223, JP-A-2019-003177, JP-A-2009-173893, etc., and can be produced according to the methods described in these documents.

[0024] A film (hereinafter also referred to as "diskous polymerizable liquid crystal retardation film") formed by fixing a discotic polymerizable liquid crystal compound aligned perpendicular to the film surface can be obtained by aligning the discotic plane of the discotic polymerizable liquid crystal compound perpendicular to the thickness direction of the liquid crystal retardation film. "Parallel" here does not require strict parallelism, but means that the angle between the discotic plane of the discotic polymerizable liquid crystal compound and the thickness direction of the liquid crystal retardation film is in the range of 0 to 10°.

[0025] The polymerizable liquid crystal compound forming the discotic liquid crystal cured retardation film can be appropriately selected from polymerizable liquid crystal compounds known in the art.Specific examples include the compounds described in JP-A-2007-108732 and JP-A-2010-244038, and can be produced according to the methods described in these documents.

[0026] A film formed by fixing rod-shaped polymerizable liquid crystal compounds twisted along a helical axis extending in the thickness direction of the retardation film can be obtained by fixing a chiral nematic phase having a so-called helical structure. Here, the twisted alignment of the rod-shaped polymerizable liquid crystal compounds means that the rod-shaped polymerizable liquid crystal compounds are twisted from one main surface to the other main surface of the liquid crystal retardation film around the thickness direction of the liquid crystal retardation film. Accordingly, the alignment direction (in-plane slow axis direction) of the rod-shaped polymerizable liquid crystal compounds varies depending on the position in the thickness direction of the liquid crystal retardation film. In the present invention, the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film both refer to the alignment direction of the liquid crystal compounds on the outermost surface on the side in contact with the adhesive layer 1. In the twisted alignment, the long axis of the rod-shaped polymerizable liquid crystal compounds is arranged parallel to the retardation film surface. The term "parallel" as used herein does not necessarily mean that the molecules are strictly parallel, but rather means that the angle between the long axis of the rod-shaped polymerizable liquid crystal compound and the in-plane direction of the liquid crystal retardation film is in the range of 0 to 10°.

[0027] The twist angle of the rod-shaped polymerizable liquid crystal compound (the twist angle of the alignment direction of the liquid crystal compound) is not particularly limited and may be, for example, more than 0° and not more than 360°, preferably within the range of 75±30°, and more preferably within the range of 75±20°. The twist angle can be measured and calculated, for example, using a polarization measuring device (polarimeter) and analysis software for the device.

[0028] When the first liquid crystal retardation film and / or the second liquid crystal retardation film is a film formed by fixing the twisted rod-like polymerizable liquid crystal compound, the value of the product Δnd of the refractive index anisotropy Δn of the liquid crystal retardation film at a wavelength of 550 nm and the thickness d of the liquid crystal retardation film is preferably 100 to 180 nm, more preferably 110 to 170 nm. Δnd can be measured and calculated, for example, using a polarization measuring device (polarimeter) that can be used to measure the twist angle, and analysis software for the device.

[0029] The polymerizable liquid crystal compound forming the film by fixing the twisted aligned rod-like polymerizable liquid crystal compound can be appropriately selected from polymerizable liquid crystal compounds known in the art.Specific examples include the compounds described in JP-A-11-513019 and JP-A-2005-289980, and can be produced according to the methods described in these documents.

[0030] The combination of the first liquid crystal retardation film and the second liquid crystal retardation film is not particularly limited as long as the alignment directions of the two films are stacked within the above-mentioned specific angle range and the desired optical properties are obtained. Examples of combinations of the first liquid crystal retardation film and the second liquid crystal retardation film include, in the order of the first liquid crystal retardation film and the second liquid crystal retardation film, a horizontally aligned rod-shaped cured liquid crystal retardation film-a horizontally aligned rod-shaped cured liquid crystal retardation film, a discotic cured liquid crystal retardation film-a horizontally aligned rod-shaped cured liquid crystal retardation film, and a discotic cured liquid crystal retardation film-a film in which a rod-shaped polymerizable liquid crystal compound is fixed and twisted along a helical axis extending in the thickness direction of the retardation film. By stacking the first liquid crystal cured retardation film and the second liquid crystal retardation film in an appropriate combination so that the alignment directions of their liquid crystal molecules satisfy the above-mentioned specific relationship, an optically anisotropic laminate having excellent reflection hue can be obtained when incorporated into a display device and displayed in black.

[0031] In the present invention, the first liquid crystal retardation film and the second liquid crystal retardation film are configured to include a liquid crystal cured film formed by aligning a polymerizable liquid crystal compound, and may be a single layer formed from the liquid crystal cured film, or may be composed of a layer formed from the liquid crystal cured film and an alignment film for forming the liquid crystal cured film. When the liquid crystal retardation film is composed of the liquid crystal cured film and an alignment film, the surface in contact with the adhesive layer 1 may be the liquid crystal cured film side or the alignment film side. When the liquid crystal retardation film is composed of the liquid crystal cured film and an alignment film, the in-plane average refractive index of the liquid crystal retardation film is a value measured with these two layers (films) combined together.

[0032] The liquid crystal retardation film can be obtained, for example, by a method including polymerizing a polymerizable liquid crystal composition for forming a retardation film (hereinafter also referred to as a "composition for forming a retardation film") containing the above-mentioned polymerizable liquid crystal compound while maintaining a desired alignment state of the polymerizable liquid crystal compound. The composition for forming a retardation film can contain additives such as a polymerization initiator, a solvent, and a leveling agent in addition to the polymerizable liquid crystal compound.

[0033] The content of the polymerizable liquid crystal compound in the retardation film-forming composition can be appropriately determined depending on the optical properties of the desired optically anisotropic laminate, the type of polymerizable liquid crystal compound used, and other factors. It is preferably 40 to 99.9% by mass, more preferably 60 to 99.9% by mass, and even more preferably 70 to 99% by mass, based on the solid content of the retardation film-forming composition. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be enhanced. In this specification, the solid content refers to the total amount of components excluding the solvent from the retardation film-forming composition. Hereinafter, when the solid content is referred to in this specification, it similarly refers to the components excluding volatile components such as the solvent from the target composition.

[0034] The retardation film-forming composition may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound or the like. As the polymerization initiator, a photopolymerization initiator that generates an active radical or an acid by the action of light is preferred, since it can initiate a polymerization reaction under lower temperature conditions, and a photopolymerization initiator that generates a radical by the action of light is more preferred. The polymerization initiator may be used alone or in combination of two or more kinds.

[0035] As the photopolymerization initiator, known photopolymerization initiators can be used. For example, photopolymerization initiators that generate active radicals include self-cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators. Examples of the self-cleaving photopolymerization initiator that can be used include self-cleaving benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, and azo compounds. Examples of the hydrogen abstraction photopolymerization initiator that can be used include hydrogen abstraction benzophenone compounds, benzoin ether compounds, benzil ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, and triazine compounds.

[0036] As the photopolymerization initiator that generates an acid, an iodonium salt, a sulfonium salt, or the like can be used.

[0037] Among these, a reaction at low temperature is preferred, and from the viewpoint of reaction efficiency at low temperature, a self-cleaving photopolymerization initiator is preferred, and an acetophenone-based compound, a hydroxyacetophenone-based compound, an α-aminoacetophenone-based compound, or an oxime ester-based compound is particularly preferred.

[0038] Specific examples of the photopolymerization initiator include the following: benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; hydroxyacetophenone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one; α-aminoacetophenone compounds such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one; Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime); acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone; Dialkoxyacetophenone compounds such as diethoxyacetophenone; 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine Triazine compounds such as riazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine. The photopolymerization initiator may be appropriately selected in relation to the polymerizable liquid crystal compound that forms the retardation film from the photopolymerization initiator, for example.

[0039] Alternatively, commercially available photopolymerization initiators may be used. Examples of commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, and OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, and Esacure KIP160 (manufactured by IDM Resins). BV); Seikuol (registered trademark) BZ, Z, and BEE (Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100 and UVI-6992 (Dow Chemical Co., Ltd.); Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arcles NCI-831, Adeka Arcles NCI-930 (ADEKA Corporation); TAZ-A and TAZ-PP (Nihon SiberHegner Co., Ltd.); and TAZ-104 (Sanwa Chemical Co., Ltd.).

[0040] The content of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, even more preferably 0.5 to 10 parts by mass, and particularly preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, the polymerization reaction can be carried out without significantly disturbing the alignment of the polymerizable liquid crystal compound.

[0041] The solvent may be appropriately selected depending on the solubility of the polymerizable liquid crystal compound to be used, and is preferably a solvent that can completely dissolve the above components and is inactive to the polymerization reaction.

[0042] Specific examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate, and ethyl lactate; and acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone. Examples of suitable solvents include ketone solvents, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, chlorine-containing solvents such as chloroform and chlorobenzene, amide solvents such as N,N-dimethylacetamide and N,N-dimethylformamide, sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane, carbonate solvents such as ethylene carbonate and propylene carbonate, and pyrrolidone solvents such as N-methylpyrrolidone. These solvents may be used alone or in combination of two or more.

[0043] The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 1000 parts by mass, and even more preferably 180 to 800 parts by mass, relative to 100 parts by mass of the solid content of the retardation film-forming composition.

[0044] The retardation film-forming composition may contain a leveling agent. The leveling agent adjusts the fluidity of the retardation film-forming composition and functions to make the coating film obtained by applying the composition flatter. Specific examples include surfactants. The leveling agent is preferably at least one selected from the group consisting of leveling agents containing a polyacrylate compound as a main component and leveling agents containing a fluorine atom-containing compound as a main component. The leveling agents can be used alone or in combination of two or more.

[0045] Examples of leveling agents containing polyacrylate compounds as their main components include BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK-361N, BYK-380, BYK-381, and BYK-392 (BYK Chemie).

[0046] Examples of leveling agents containing a fluorine atom-containing compound as a main component include 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, and F-556 (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, Inc.); F-top EF301, F-top EF303, F-top EF351, and F-top EF352 (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

[0047] When the composition for forming a retardation film contains a leveling agent, the content thereof is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily aligned, unevenness is less likely to occur, and a smoother retardation film tends to be obtained.

[0048] The retardation film-forming composition may contain additives other than the leveling agent. Examples of the additives include ionic compounds, polymerizable non-liquid crystal compounds, photosensitizers, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the retardation film-forming composition contains other additives, the content of the additives is preferably more than 0% and not more than 20% by mass, more preferably more than 0% and not more than 10% by mass, based on the solid content of the polarizing film-forming composition.

[0049] The composition for forming a retardation film can be produced by a conventionally known method for preparing a liquid crystal composition, and can usually be prepared by mixing and stirring a polymerizable liquid crystal compound, and, if necessary, a polymerization initiator, a solvent, the above-mentioned additives, etc.

[0050] In one embodiment of the present invention, the liquid crystal retardation film is aligned by an alignment film, and in this case, the liquid crystal retardation film may include an alignment film. The alignment films for forming the first liquid crystal retardation film and the second liquid crystal retardation film have an alignment control force that aligns the polymerizable liquid crystal compound in a desired direction, and a precisely aligned liquid crystal retardation film can be easily obtained by applying a retardation film-forming composition onto the alignment film. The alignment film preferably has solvent resistance that prevents the retardation film-forming composition from dissolving when applied, and also has heat resistance to remove the solvent and to align the polymerizable liquid crystal compound through heat treatment.

[0051] When an alignment film is included, it is preferable that the alignment film does not significantly affect the refractive index of the liquid crystal retardation film. For example, by controlling the in-plane refractive index at a wavelength of 589 nm, thickness, etc. of the alignment film, an alignment film that is less likely to affect the refractive index of the liquid crystal retardation film can be formed. Furthermore, after forming a liquid crystal retardation film using an alignment film, the alignment film can be peeled off and only the retardation film can be laminated with other layers to obtain an optical laminate that does not include an alignment film. In one embodiment of the present invention, neither the first liquid crystal retardation film nor the second liquid crystal retardation film includes an alignment film.

[0052] Examples of the alignment film include an alignment film containing an orientable polymer, a photo-alignment film, a groove alignment film having a concave-convex pattern or a plurality of grooves on the surface, a stretched film stretched in the alignment direction, etc. These various alignment films can be appropriately selected from those conventionally known in the art according to the desired alignment control force.

[0053] In one embodiment of the present invention, when the first liquid crystal retardation film and / or the second liquid crystal retardation film are formed using an alignment film, it is preferable that at least one of them is a photo-alignment film, from the viewpoints of easily improving alignment precision and adhesion with a liquid crystal cured film formed from a polymerizable liquid crystal composition. That is, a liquid crystal cured film may be formed on the photo-alignment film. The photo-alignment film is also advantageous in that the direction of the alignment restraint force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0054] Photo-alignment films are typically obtained by applying a composition containing a polymer, oligomer, or monomer having a photoreactive group and a solvent (hereinafter also referred to as a "photo-alignment film-forming composition") to a substrate or the like and then irradiating the coated surface with polarized light (preferably polarized UV). The photoreactive group refers to a group that exhibits liquid crystal alignment ability upon irradiation with light. Specific examples include groups that are involved in photoreactions that induce molecular alignment upon irradiation or that are the origin of liquid crystal alignment ability, such as isomerization, dimerization, photocrosslinking, or photodecomposition. Among these, groups that participate in dimerization or photocrosslinking are preferred because of their excellent alignment properties. As the photoreactive group, groups having an unsaturated bond, particularly a double bond, are preferred, and groups having at least one bond selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) are particularly preferred.

[0055] Specific examples of such alignment films include photoalignment films such as those described in JP 2021-196514 A and WO 2018 / 003416 A.

[0056] The thickness of the alignment film is usually 10 to 5000 nm, preferably 10 to 1000 nm, more preferably 10 to 500 nm, still more preferably 10 to 300 nm, and particularly preferably 30 to 300 nm. When the thickness of the alignment film is within the above range, the alignment film can exhibit good adhesion at the interface with a cured material layer formed from a polymerizable liquid crystal compound on the alignment film, while exhibiting alignment regularity, and can form a liquid crystal retardation film with high alignment order.

[0057] The liquid crystal retardation film can be produced by, for example, forming a coating film of a retardation film-forming composition, removing the solvent from the coating; raising the temperature to a temperature at which the polymerizable liquid crystal compound undergoes a phase transition to a liquid phase or higher, and then lowering the temperature to cause the polymerizable liquid crystal compound to undergo a phase transition to a liquid crystal phase; and polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal phase; It can be produced by a method comprising:

[0058] The formation of a coating film of the retardation film-forming composition can be carried out, for example, by applying the composition onto a substrate or an alignment film. The substrate can be a layer constituting the optically anisotropic laminate of the present invention, but in one embodiment of the present invention, it is preferable that it is finally peeled off. As the substrate, a resin film substrate or the like conventionally known in the field of optical films can be used. Examples of resins constituting such resin films include polyolefin-based resins such as polyethylene and polypropylene; cycloolefin-based resins such as norbornene-based polymers; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; poly(meth)acrylic acid-based resins such as (meth)acrylic acid and polymethyl(meth)acrylate; cellulose ester-based resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate-based resins; polystyrene-based resins; polyarylate-based resins; polysulfone-based resins; polyethersulfone-based resins; polyamide-based resins; polyimide-based resins; polyether ketone-based resins; polyphenylene sulfide-based resins; polyphenylene oxide-based resins, and mixtures thereof. These may be used alone or in combination of two or more. Such resins can be formed into a film by known means such as solvent casting or melt extrusion to form a resin film substrate. Commercially available products may also be used as the film substrate or the resin constituting the film substrate.

[0059] The film substrate may be subjected to a surface treatment such as corona treatment or plasma treatment, and may also be subjected to a release treatment if the substrate is to be peeled off later. The thickness of the substrate is not particularly limited and may be appropriately selected within a practical range. For example, it may be about 5 to 300 μm.

[0060] The method for applying the retardation film-forming composition is not particularly limited, and known methods such as application methods such as spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods, and printing methods such as flexography can be used.

[0061] When the retardation film-forming composition contains a solvent, the solvent is usually removed from the applied composition. Examples of methods for removing the solvent include natural drying, forced air drying, heat drying, and reduced-pressure drying. The dried film is preferably dried so that the residual solvent in the retardation film is 1% by weight or less relative to the total mass of the retardation film. The amount of residual solvent can be determined by peeling the retardation film from the substrate, weighing it, immersing the retardation film in a solvent that dissolves the retardation film, such as tetrahydrofuran, irradiating it with ultrasound for about 10 minutes to extract the dissolved components, and then analyzing the solution by gas chromatography. The drying conditions, such as the drying temperature and drying time, can be appropriately determined depending on the composition of the retardation film-forming composition, the materials of the substrate and alignment film, and the like.

[0062] The polymerizable liquid crystal compound in the coating film is usually oriented to form a liquid crystal phase by heating it to a temperature at which it transitions to a liquid crystal state or a solution state or higher, and then cooling it to a temperature at which the liquid crystal aligns.

[0063] The temperature at which the polymerizable liquid crystal compound in the coating film is oriented can be determined in advance by observing the texture of a composition containing the polymerizable liquid crystal compound. Alternatively, the solvent removal and liquid crystal orientation may be performed simultaneously. The temperature at this time varies depending on the type of solvent to be removed and the type of polymerizable liquid crystal compound used, but is preferably in the range of 50 to 200°C, more preferably 80 to 130°C.

[0064] The retardation film is formed as a cured layer of the liquid crystal composition by polymerizing and curing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the polymerizable liquid crystal compound. Photopolymerization is a preferred polymerization method. In photopolymerization, the light irradiated onto the dried film is appropriately selected depending on the type of polymerizable liquid crystal compound contained in the dried film (particularly the type of polymerizable group possessed by the polymerizable liquid crystal compound), the type and amount of polymerization initiator, etc.

[0065] Examples of light sources for actinic rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0066] The ultraviolet irradiation intensity is appropriately determined depending on the composition of the retardation film-forming composition and is not particularly limited, but is usually 10 to 3,000 mW / cm 2 The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the polymerization initiator. The light irradiation time is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiating once or multiple times with such ultraviolet irradiation intensity, the cumulative light amount is 10 to 3,000 mJ / cm. 2 , preferably 50 to 2,000 mJ / cm 2 , more preferably 100 to 1,000 mJ / cm 2 is.

[0067] In the optically anisotropic laminate of the present invention, the adhesive layer 1 is a layer capable of bonding the first liquid crystal retardation film and the second liquid crystal retardation film, and can be formed from, for example, a known adhesive. Examples of adhesives that can form the adhesive layer 1 include pressure-sensitive adhesives whose main component is a resin such as a (meth)acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin, as well as active energy ray-curable adhesives, water-based adhesives, organic solvent-based adhesives, and solventless adhesives.

[0068] The adhesive may be an active energy ray-curable adhesive, a thermosetting adhesive, or the like. The (meth)acrylic resin (base polymer) used in the adhesive forming the adhesive layer 1 may be, for example, a polymer or copolymer containing one or more (meth)acrylic acid esters as monomer components, such as butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isobornyl (meth)acrylate. The (meth)acrylic resin may also be a copolymer of a polar monomer. Examples of polar monomers include monomers having a carboxylic acid group, a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, and glycidyl (meth)acrylate.

[0069] In one embodiment of the present invention, the structural units derived from (meth)acrylic acid esters in the (meth)acrylic resin constituting the PSA preferably account for 80 to 100 mass %, more preferably 85 mass % or more, and even more preferably 90 mass % or more of the total mass of all structural units constituting the (meth)acrylic resin. Furthermore, when the (meth)acrylic resin contains structural units derived from polar monomers, the structural units derived from the polar monomers preferably account for 0.1 to 10 mass %, more preferably 0.5 mass % or more, even more preferably 1 mass % or more, and even more preferably 8 mass % or less of the total mass of all structural units constituting the (meth)acrylic resin.

[0070] The weight-average molecular weight (hereinafter also simply referred to as "Mw") of the (meth)acrylic resin is preferably 500,000 to 2,500,000. When the weight-average molecular weight is 500,000 or more, the durability of the pressure-sensitive adhesive layer can be improved in high-temperature, high-humidity environments. When the weight-average molecular weight is 2,500,000 or less, the operability when applying the pressure-sensitive adhesive is improved. The molecular weight distribution (Mw / Mn), which is 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, the weight-average molecular weight and number-average molecular weight are polystyrene-equivalent values ​​measured by gel permeation chromatography (GPC).

[0071] The pressure-sensitive adhesive may contain only the acrylic resin, or may contain a crosslinking agent in combination. Examples of crosslinking agents include divalent or higher metal ions that form metal carboxylates with carboxyl groups; polyamine compounds that form amide bonds with carboxyl groups; polyepoxy compounds or polyols that form ester bonds with carboxyl groups; and polyisocyanate compounds that form amide bonds with carboxyl groups. Among these, polyisocyanate compounds are preferred from the standpoints of crosslinking speed, durability, etc.

[0072] When a crosslinking agent is contained, the proportion thereof is, for example, 0.01 to 10 parts by mass, preferably 0.1 to 3 parts by mass, and more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the base polymer.

[0073] The pressure-sensitive adhesive may further contain a silane compound, if necessary. The inclusion of a silane compound can enhance the adhesion between the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive and the layer to be laminated. 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. These compounds may be used alone or in combination of two or more.

[0074] When a silane compound is contained, the content thereof in the adhesive is usually 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass, per 100 parts by mass of the base polymer.

[0075] In this specification, an active energy ray-curable pressure-sensitive adhesive refers to a pressure-sensitive adhesive that has the property of being cured when irradiated with active energy rays such as ultraviolet rays or electron beams, that has adhesiveness even before being irradiated with active energy rays and can be adhered to an adherend such as a film, and that has the property of being cured by irradiation with active energy rays and allowing adjustment of adhesion strength, etc. The active energy ray-curable pressure-sensitive adhesive is preferably an ultraviolet ray-curable pressure-sensitive adhesive.

[0076] The active energy ray-curable pressure-sensitive adhesive generally contains an energy ray-polymerizable compound in addition to a base polymer such as the (meth)acrylic resin and a crosslinking agent as described above, and may further contain a photopolymerization initiator, a photosensitizer, etc., as necessary.

[0077] Examples of the active energy ray-polymerizable compound include (meth)acrylic compounds such as (meth)acrylate monomers having at least one (meth)acryloyloxy group in the molecule; and (meth)acryloyloxy group-containing compounds such as (meth)acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyloxy groups in the molecule.

[0078] The PSA may further contain conventional components commonly used as components constituting PSA, such as resins other than the base polymer, tackifiers, fillers (metal powders and other inorganic powders, etc.), antioxidants, UV absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, and other additives.

[0079] In one embodiment of the present invention, the pressure-sensitive adhesive layer 1 may be composed of a reaction product of a pressure-sensitive adhesive containing a base polymer such as the (meth)acrylic resin, a crosslinking agent, and a silane compound as described above. Such a pressure-sensitive adhesive layer 1 can be formed by applying, for example, an organic solvent diluted solution of a pressure-sensitive adhesive containing the above components to a surface on which the pressure-sensitive adhesive layer is to be formed, and drying the applied solution.

[0080] In one embodiment of the present invention, the pressure-sensitive adhesive layer 1 may be a layer formed from an active energy ray-curable pressure-sensitive adhesive. When the pressure-sensitive adhesive layer is formed from an active energy ray-curable pressure-sensitive adhesive, for example, an organic solvent diluted solution of the pressure-sensitive adhesive comprising the components described above is applied to a surface on which the pressure-sensitive adhesive layer is to be formed, and the adhesive layer is dried to form a pressure-sensitive adhesive layer, which can be irradiated with active energy rays to form a cured product layer having a desired degree of curing.

[0081] In the optical laminate of the present invention, the storage modulus of the adhesive layer 1 at a temperature of 23°C is preferably 0.05 MPa or more, more preferably 0.08 MPa or more, even more preferably 0.1 MPa or more, and preferably 0.5 MPa or less, more preferably 0.3 MPa or less, and even more preferably 0.2 MPa or less. Furthermore, the storage modulus of the adhesive layer 1 at a temperature of 80°C is preferably 0.01 MPa or more, more preferably 0.03 MPa or more, even more preferably 0.05 MPa or more, and preferably 0.5 MPa or less, more preferably 0.2 MPa or less, and even more preferably 0.15 MPa or less. When the storage modulus of the adhesive layer 1 is within the above range, misalignment is less likely to occur between the layers bonded via the adhesive layer 1. The storage modulus of the adhesive layer 1 can be controlled within a desired range by, for example, the composition of the adhesive forming the adhesive layer 1. The storage modulus of the pressure-sensitive adhesive layer 1 can be measured using a viscoelasticity measuring device. In detail, it can be measured by the method described in the examples below, for example.

[0082] In one embodiment of the present invention, the adhesive layer 1 is preferably an active energy ray-curable adhesive from the viewpoint of the preferable in-plane average refractive index. Active energy ray-curable adhesives are adhesives that cure upon exposure to active energy rays such as ultraviolet rays. Examples of active energy ray-curable adhesives include cationic polymerization adhesives containing a cationic polymerizable compound as the curable compound, radical polymerization adhesives containing a radical polymerizable compound as the curable compound, and hybrid adhesives containing both a cationic polymerizable compound and a radical polymerizable compound. Among these, cationic polymerization active energy ray-curable adhesives containing a cationic polymerizable compound and a photocationic polymerization initiator, and radical polymerization active energy ray-curable adhesives containing a radical polymerizable compound and a photoradical polymerization initiator are preferred. Specific examples of cationic polymerizable compounds include epoxy compounds having one or more epoxy groups in the molecule, oxetane compounds having one or more oxetane rings in the molecule, and vinyl compounds. Specific examples of radical polymerizable compounds include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, vinyl compounds, and the like. The adhesive may contain one or more cationic polymerizable compounds and / or one or more radical polymerizable compounds.

[0083] The cationically polymerizable compound that is the main component of the cationically polymerizable adhesive refers to a compound or oligomer that undergoes a cationic polymerization reaction and hardens when exposed to active energy rays such as ultraviolet light, visible light, electron beams, or X-rays or when heated, and examples of such compounds include epoxy compounds, oxetane compounds, and vinyl compounds. Of these, the preferred cationically polymerizable compound is an epoxy compound.

[0084] An epoxy compound is a compound having one or more, preferably two or more, epoxy groups in the molecule. One type of epoxy compound may be used alone, or two or more types may be used in combination. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. From the viewpoints of weather resistance, curing speed, and adhesiveness, it is preferable that the epoxy compound contains an alicyclic epoxy compound or an aliphatic epoxy compound.

[0085] Alicyclic epoxy compounds are compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule, such as alicyclic epoxy compounds having an epoxycyclopentane structure or an epoxycyclohexane structure. Specific examples include 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, ethylene bis(3,4-epoxycyclohexanecarboxylate), bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, diethylene glycol bis(3,4-epoxycyclohexylmethyl) ether), ethylene glycol bis(3,4-epoxycyclohexyl methyl ether), 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]heneicosane, 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane, 4-vinylcyclohexene dioxide, limonene dioxide, bis(2,3-epoxycyclopentyl)ether, dicyclopentadiene dioxide, etc.

[0086] Aromatic epoxy compounds are compounds having an aromatic ring and an epoxy group in the molecule. Specific examples include bisphenol-type epoxy compounds or oligomers thereof, such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; novolac-type epoxy resins, such as phenol novolac epoxy resin, cresol novolac epoxy resin, and hydroxybenzaldehyde phenol novolac epoxy resin; polyfunctional epoxy compounds, such as glycidyl ether of 2,2',4,4'-tetrahydroxydiphenylmethane and glycidyl ether of 2,2',4,4'-tetrahydroxybenzophenone; and polyfunctional epoxy resins, such as epoxidized polyvinylphenol.

[0087] The hydrogenated epoxy compound is a glycidyl ether of a polyol having an alicyclic ring, and may be a glycidyl ether of a nuclear-hydrogenated polyhydroxy compound obtained by selectively hydrogenating the aromatic ring of an aromatic polyol in the presence of a catalyst under pressure. Specific examples of aromatic polyols include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; novolac-type resins such as phenol novolac resin, cresol novolac resin, and hydroxybenzaldehyde phenol novolac resin; and polyfunctional compounds such as tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, and polyvinylphenol. A glycidyl ether can be obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol, for example, a diglycidyl ether of hydrogenated bisphenol A.

[0088] Aliphatic epoxy compounds are compounds that have at least one oxirane ring (three-membered cyclic ether) bonded to an aliphatic carbon atom in the molecule. Examples include monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; bifunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether; trifunctional or higher epoxy compounds such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; and epoxy compounds that have one epoxy group directly bonded to an alicyclic ring and an oxirane ring bonded to an aliphatic carbon atom, such as 4-vinylcyclohexene dioxide and limonene dioxide. Among these, bifunctional epoxy compounds (also known as aliphatic diepoxy compounds) that have two oxirane rings bonded to an aliphatic carbon atom in the molecule are preferred.

[0089] Oxetane compounds, a type of cationically polymerizable compound, are compounds containing one or more oxetane rings (oxetanyl groups) in the molecule. Specific examples include 3-ethyl-3-hydroxymethyloxetane (also known as oxetane alcohol), 2-ethylhexyloxetane, 1,4-bis[{(3-ethyloxetan-3-yl)methoxy}methyl]benzene (also known as xylylene bisoxetane), 3-ethyl-3[{(3-ethyloxetan-3-yl)methoxy}methyl]oxetane, 3-ethyl-3-(phenoxymethyl)oxetane, and 3-(cyclohexyloxy)methyl-3-ethyloxetane. Oxetane compounds may be used as the main component of the cationically polymerizable compound or in combination with an epoxy compound. The use of an oxetane compound in combination can improve the curing speed and adhesive properties of adhesives.

[0090] Examples of vinyl compounds that can be cationic polymerizable compounds include aliphatic or alicyclic vinyl ether compounds. Specific examples thereof include vinyl ethers of alkyl or alkenyl alcohols having 5 to 20 carbon atoms, such as n-amyl vinyl ether, i-amyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, and oleyl vinyl ether; hydroxyl group-containing vinyl ethers, such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, and 4-hydroxybutyl vinyl ether; vinyl ethers of monoalcohols having an aliphatic or aromatic ring, such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, and benzyl vinyl ether; glycerol monovinyl ether, 1,4-butanediol monovinyl ether, 1,4-butanediol divinyl ether, and 1,6-hexanediol divinyl ether. Examples of suitable vinyl compounds include mono- and polyvinyl ethers of polyhydric alcohols such as 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane divinyl ether, 1,4-dihydroxymethylcyclohexane monovinyl ether, and 1,4-dihydroxymethylcyclohexane divinyl ether; polyalkylene glycol mono- and divinyl ethers such as diethylene glycol divinyl ether, triethylene glycol divinyl ether, and diethylene glycol monobutyl monovinyl ether; and other vinyl ethers such as glycidyl vinyl ether and ethylene glycol vinyl ether methacrylate. Vinyl compounds may be used as the main component of the cationically polymerizable compound, or may be used in combination with an epoxy compound, or an epoxy compound and an oxetane compound. The use of vinyl compounds in combination can improve the adhesive's curing speed and reduce its viscosity.

[0091] The cationically polymerizable adhesive may further contain other cationically polymerizable compounds in addition to those mentioned above, such as a cyclic lactone compound, a cyclic acetal compound, a cyclic thioether compound, or a spiroorthoester compound.

[0092] In one embodiment of the present invention, when the adhesive contains a cationically polymerizable compound, it is preferable that the adhesive contains an epoxy compound as the cationically polymerizable compound. In this case, the content of the epoxy compounds (the total content when two or more types are contained) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, relative to 100% by mass of the total amount of the cationically polymerizable compounds.

[0093] When the total amount of curable compounds contained in an adhesive (including hybrid types) containing a cationically polymerizable compound is taken as 100% by mass, the content of the cationically polymerizable compounds (the total content when two or more types are contained) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The cationically polymerizable adhesive may further contain a polymer component (such as a thermoplastic resin).

[0094] When the adhesive contains a cationic polymerizable compound, it preferably contains a cationic photopolymerization initiator. The cationic photopolymerization initiator generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, or electron beams, thereby initiating the polymerization reaction of the cationic curable compound. Because the cationic photopolymerization initiator acts catalytically under light, it exhibits excellent storage stability and workability even when mixed with the cationic photocurable compound. Examples of compounds that generate cationic species or Lewis acids upon irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, and iron-arene complexes.

[0095] The aromatic iodonium salt is a compound having a diaryliodonium cation, and a typical example of the cation is a diphenyliodonium cation. The aromatic sulfonium salt is a compound having a triarylsulfonium cation, and a typical example of the cation is a triphenylsulfonium cation or a 4,4'-bis(diphenylsulfonio)diphenylsulfide cation. The aromatic diazonium salt is a compound having a diazonium cation, and a typical example of the cation is a benzenediazonium cation. The iron-arene complex is typically a cyclopentadienyliron(II) arene cation complex salt.

[0096] The cations shown above are paired with anions (negative ions) to form cationic photopolymerization initiators. Examples of anions that form cationic photopolymerization initiators include special phosphorus anions [(Rf) n PF 6-n ] - , hexafluorophosphate anion PF6 - , hexafluoroantimonate anion SbF6 - , pentafluorohydroxyantimonate anion SbF5(OH) - , hexafluoroarsenate anion AsF6 - , tetrafluoroborate anion BF4 - , tetrakis(pentafluorophenyl)borate anion B(C6F5)4 - Among them, from the viewpoint of the curing property of the cationic polymerizable compound and the safety of the resulting adhesive layer, a special phosphorus-based anion [(Rf) n PF 6-n ] - , hexafluorophosphate anion PF6 - It is preferable that:

[0097] The cationic photopolymerization initiator may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are preferred because they have ultraviolet absorption properties even in the wavelength region around 300 nm, and therefore can form an adhesive layer with excellent curability, mechanical strength, and adhesive strength.

[0098] The content of the cationic photopolymerization initiator in the adhesive is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of the solid content of the curable compound. When the content of the cationic photopolymerization initiator is within the above range, the cationic polymerizable compound can be sufficiently cured, and the resulting adhesive layer can be imparted with high mechanical strength and adhesive strength.

[0099] A hybrid curable composition can also be produced by incorporating a radically polymerizable compound into a cationically polymerizable adhesive. The combined use of a radically polymerizable compound is expected to increase the hardness and mechanical strength of the adhesive layer, and furthermore, makes it easier to adjust the viscosity and curing speed of the adhesive.

[0100] The radical polymerizable compound, which is the main component of radical polymerization adhesives, refers to a compound or oligomer that undergoes a radical polymerization reaction and hardens when exposed to active energy rays such as ultraviolet light, visible light, electron beams, or X-rays, or when heated. Specific examples include compounds having an ethylenically unsaturated bond. Examples of compounds having an ethylenically unsaturated bond include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, as well as vinyl compounds such as styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone. Among these, the preferred radical polymerizable compound is a (meth)acrylic compound.

[0101] A (meth)acrylic compound is a compound having at least one (meth)acryloyloxy group in the molecule, and may be a monomer, oligomer, or polymer. Examples of (meth)acrylic compounds include (meth)acrylate compounds such as monofunctional (meth)acrylate compounds and polyfunctional (meth)acrylate compounds; urethane (meth)acrylate compounds such as polyfunctional urethane (meth)acrylate compounds; epoxy (meth)acrylate compounds such as polyfunctional epoxy (meth)acrylate compounds; carboxyl group-modified epoxy (meth)acrylate compounds, polyester (meth)acrylate compounds, and the like. One (meth)acrylic compound may be used alone, or two or more may be used in combination. In this specification, "(meth)acrylate" means "acrylate" or "methacrylate," and similarly, "(meth)acryloyl" and the like mean "acryloyl" or "methacryloyl."

[0102] Examples of the (meth)acrylate compound include a monofunctional (meth)acrylate compound having one (meth)acryloyloxy group in the molecule, and a polyfunctional (meth)acrylate compound having two or more (meth)acryloyloxy groups in the molecule.

[0103] An example of a monofunctional (meth)acrylate monomer is alkyl(meth)acrylate. In the alkyl(meth)acrylate, when the alkyl group has three or more carbon atoms, the alkyl(meth)acrylate may be linear or branched. Specific examples of alkyl(meth)acrylate include methyl(meth)acrylate, ethyl(meth)acrylate, isopropyl(meth)acrylate, butyl(meth)acrylate, isobutyl(meth)acrylate, t-butyl(meth)acrylate, and 2-ethylhexyl(meth)acrylate. Also, aralkyl (meth)acrylates such as benzyl (meth)acrylate; (meth)acrylates of terpene alcohols such as isobornyl (meth)acrylate; (meth)acrylates having a tetrahydrofurfuryl structure such as tetrahydrofurfuryl (meth)acrylate; (meth)acrylates having a cycloalkyl group in the alkyl group moiety such as cyclohexyl (meth)acrylate, cyclohexylmethyl methacrylate, dicyclopentanyl acrylate, dicyclopentenyl (meth)acrylate, and 1,4-cyclohexanedimethanol monoacrylate. (Meth)acrylates having a group; aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate; and (meth)acrylates having an ether bond in the alkyl moiety such as 2-phenoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and phenoxypolyethylene glycol (meth)acrylate can also be used as monofunctional (meth)acrylate monomers.

[0104] Examples of bifunctional (meth)acrylate monomers include alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and dipropylene glycol. Polyoxyalkylene glycol di(meth)acrylates such as di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate; di(meth)acrylates of halogen-substituted alkylene glycols such as tetrafluoroethylene glycol di(meth)acrylate; trimethylolpropane di(meth)acrylate, ditrimethylolpropane di(meth)acrylate di(meth)acrylates of aliphatic polyols such as pentaerythritol di(meth)acrylate; di(meth)acrylates of hydrogenated dicyclopentadiene or tricyclodecane dialkanol such as hydrogenated dicyclopentadienyl di(meth)acrylate and tricyclodecane dimethanol di(meth)acrylate; di(meth)acrylates of dioxane glycol or dioxane dialkanol such as 1,3-dioxane-2,5-diyl di(meth)acrylate (also known as dioxane glycol di(meth)acrylate); bisphenol A esters Di(meth)acrylates of alkylene oxide adducts of bisphenol A or bisphenol F, such as ethylene oxide adduct diacrylate and bisphenol F ethylene oxide adduct diacrylate; epoxy di(meth)acrylates of bisphenol A or bisphenol F, such as acrylic acid adduct of bisphenol A diglycidyl ether and acrylic acid adduct of bisphenol F diglycidyl ether; silicone di(meth)acrylate; di(meth)acrylate of hydroxypivalic acid neopentyl glycol ester;Examples include 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane; 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane; di(meth)acrylate of 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane; tris(hydroxyethyl)isocyanurate di(meth)acrylate; and fluorene skeleton-containing bifunctional (meth)acrylate.

[0105] The trifunctional (meth)acrylate monomer is a monomer having three (meth)acryloyloxy groups in the molecule, and examples thereof include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, reaction products of pentaerythritol tri(meth)acrylate and acid anhydride, caprolactone-modified trimethylolpropane tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, tri(meth)acrylate, ethylene oxide-modified pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified pentaerythritol tri(meth)acrylate, isocyanurate tri(meth)acrylate, a reaction product of caprolactone-modified pentaerythritol tri(meth)acrylate with an acid anhydride, a reaction product of ethylene oxide-modified pentaerythritol tri(meth)acrylate with an acid anhydride, and a reaction product of propylene oxide-modified pentaerythritol tri(meth)acrylate with an acid anhydride.

[0106] The tetrafunctional (meth)acrylate monomer is a monomer having four (meth)acryloyloxy groups in the molecule, and examples thereof include ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth)acrylate, caprolactone-modified tripentaerythritol tetra(meth)acrylate, ethylene oxide-modified pentaerythritol tetra(meth)acrylate, ethylene oxide-modified tripentaerythritol tetra(meth)acrylate, propylene oxide-modified pentaerythritol tetra(meth)acrylate, and propylene oxide-modified tripentaerythritol tetra(meth)acrylate.

[0107] Examples of the pentafunctional (meth)acrylate monomer include dipentaerythritol penta(meth)acrylate, tripentaerythritol penta(meth)acrylate, a reaction product of dipentaerythritol penta(meth)acrylate with an acid anhydride, caprolactone-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified tripentaerythritol penta(meth)acrylate, ethylene oxide-modified dipentaerythritol penta(meth)acrylate, and ethylene oxide-modified tripentaerythritol penta(meth)acrylate. Examples of the dipentaerythritol penta(meth)acrylate include dipentaerythritol penta(meth)acrylate, propylene oxide-modified dipentaerythritol penta(meth)acrylate, propylene oxide-modified tripentaerythritol penta(meth)acrylate, a reaction product of caprolactone-modified dipentaerythritol penta(meth)acrylate with an acid anhydride, a reaction product of ethylene oxide-modified dipentaerythritol penta(meth)acrylate with an acid anhydride, and a reaction product of propylene oxide-modified dipentaerythritol penta(meth)acrylate with an acid anhydride.

[0108] Examples of hexafunctional (meth)acrylate monomers include dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified tripentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified tripentaerythritol hexa(meth)acrylate, propylene oxide-modified dipentaerythritol hexa(meth)acrylate, and propylene oxide-modified tripentaerythritol hexa(meth)acrylate.

[0109] Examples of the heptafunctional (meth)acrylate monomer include tripentaerythritol hepta(meth)acrylate, a reaction product of tripentaerythritol hepta(meth)acrylate and an acid anhydride, caprolactone-modified tripentaerythritol hepta(meth)acrylate, a reaction product of caprolactone-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride, ethylene oxide-modified tripentaerythritol hepta(meth)acrylate, a reaction product of ethylene oxide-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride, propylene oxide-modified tripentaerythritol hepta(meth)acrylate, and a reaction product of propylene oxide-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride.

[0110] The octafunctional (meth)acrylate monomer is a monomer having eight (meth)acryloyloxy groups in the molecule, and examples thereof include tripentaerythritol octa(meth)acrylate, caprolactone-modified tripentaerythritol octa(meth)acrylate, ethylene oxide-modified tripentaerythritol octa(meth)acrylate, and propylene oxide-modified tripentaerythritol octa(meth)acrylate.

[0111] When a polyfunctional (meth)acrylate compound is used, the crosslink density of the adhesive layer can be adjusted by controlling the molecular weight between crosslinks and the number of crosslinks of the compound. More specifically, the smaller the molecular weight between crosslinks, the higher the crosslink density, and the more the number of crosslinks, the denser the crosslink density. This improves adhesion.

[0112] The urethane (meth)acrylate compound generally refers to a reaction product of an isocyanate compound, a polyol compound, and a (meth)acrylate compound, and is preferably a polyfunctional urethane (meth)acrylate compound having two or more (meth)acryloyloxy groups in the molecule. The polyfunctional urethane (meth)acrylate compound can form a crosslinked structure, thereby improving the adhesion of the adhesive layer and imparting appropriate toughness. The number of functional groups in the polyfunctional urethane (meth)acrylate compound is preferably 2 to 5.

[0113] Examples of epoxy (meth)acrylate compounds include polyfunctional epoxy (meth)acrylates that can be obtained by an addition reaction between polyglycidyl ether and (meth)acrylic acid and have at least two (meth)acryloyloxy groups in the molecule. Examples of polyester (meth)acrylate compounds include compounds that have an ester bond and at least two (meth)acryloyl groups (typically (meth)acryloyloxy groups) in the molecule.

[0114] In one embodiment of the present invention, when the adhesive contains a radical polymerizable compound, it is preferable that the radical polymerizable compound contains a (meth)acrylate compound. In this case, the content of the (meth)acrylate compound (the total content when two or more types are contained) is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, relative to 100% by mass of the total amount of the radical polymerizable compounds.

[0115] In one embodiment of the present invention, when the adhesive contains a radically polymerizable compound, it is preferable that the radically polymerizable compound contains a polyfunctional (meth)acrylate compound. In this case, the content of the polyfunctional (meth)acrylate compound is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 60% by mass or more, relative to 100% by mass of the total amount of the radically polymerizable compounds. For example, it may be 80% by mass or more, or 100% by mass or more. When the content of the polyfunctional (meth)acrylate compound is within the above range, it is easy to control the refractive index of the adhesive layer within the desired range.

[0116] When the adhesive contains a radical polymerizable compound, it preferably contains a photoradical polymerization initiator. The photoradical polymerization initiator initiates the polymerization reaction of the radical curable compound when irradiated with active energy rays such as visible light, ultraviolet light, X-rays, or electron beams. The photoradical polymerization initiator may be used alone or in combination of two or more.

[0117] Specific examples of the photoradical polymerization initiator include acetophenone-based initiators such as acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; and 2,2-dimethylbenzophenone. Alkylphenone initiators such as 1,2-diphenylethan-1-one and 1-hydroxycyclohexylphenyl ketone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; acylphosphine oxide initiators such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; and others such as xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone.

[0118] The content of the photoradical polymerization initiator in the adhesive is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of the solid content of the curable compound. When the content of the photoradical polymerization initiator is within the above range, polymerization initiation ability can be fully exerted, and curability can be improved.

[0119] The adhesive may contain additives such as a cationic polymerization accelerator, a photosensitizer, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow adjuster, a plasticizer, an antifoaming agent, an antistatic agent, and a leveling agent, as needed.

[0120] In the present invention, the adhesive may contain an organic solvent, for example, to adjust the viscosity to a level suitable for the coating method to be used, or may be substantially solvent-free (solvent-free). Note that "substantially solvent-free" does not exclude cases where solvent is inevitably mixed in.

[0121] The solvent may be any solvent capable of dissolving each component of the adhesive, and examples thereof include those exemplified above as solvents usable in the retardation film-forming composition. The solvents may be used alone or in combination of two or more.

[0122] The type and content of the solvent are appropriately selected depending on the type and content of the components constituting the adhesive layer, the shape, the application method, the thickness of the adhesive layer, etc. When a solvent is included, the amount thereof is, for example, preferably 3 to 1000 parts by mass, more preferably 5 to 100 parts by mass, and even more preferably 7 to 50 parts by mass per 100 parts by mass of the solid content of the adhesive.

[0123] The adhesive layer can be obtained, for example, by applying an adhesive to the surface on which the adhesive layer is to be formed, and irradiating the coating with active energy rays to cure the adhesive. The method for applying and curing the adhesive is not particularly limited and can be appropriately selected from conventionally known general methods for forming an adhesive layer. For example, the same methods and conditions as those exemplified above can be used as the method for applying and curing the composition for forming a retardation film.

[0124] In one embodiment of the present invention, the adhesive layer 1 is preferably an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound, more preferably an ultraviolet-curable adhesive layer containing a (meth)acrylic compound. When the adhesive layer 1 is configured to contain such a component, it becomes easier to control the refractive index of the adhesive layer 1 within the above-mentioned specific range, and the effect of suppressing light reflection at the interface with the adjacent liquid crystal retardation film can be enhanced. In particular, when the adhesive layer is an ultraviolet-curable adhesive layer containing a (meth)acrylic compound, in addition to the light reflection suppression effect, the effect of suppressing interference unevenness in the optically anisotropic laminate can be enhanced.

[0125] In one embodiment of the present invention, the optically anisotropic laminate may include a third liquid crystal retardation film on the surface of the second liquid crystal retardation film opposite to the adhesive layer 1, via an adhesive layer 2. When the third liquid crystal retardation film is included, the third liquid crystal retardation film is preferably laminated adjacent to the surface of the second liquid crystal retardation film opposite to the adhesive layer 1, via the adhesive layer 2.

[0126] The in-plane average refractive index of the third liquid crystal retardation film at a wavelength of 589 nm can be appropriately determined depending on the in-plane average refractive index of the adhesive layer 2 adjacent thereto, the in-plane average refractive index of the first liquid crystal retardation film and the second liquid crystal retardation film, the optical properties required of the optically anisotropic laminate, etc. In one embodiment of the present invention, for example, it is preferably 1.45 to 1.65, more preferably 1.50 to 1.60. When the in-plane average refractive index of the third liquid crystal retardation film is within the above range, it is easy to control the refractive index difference in relation to the adhesive layer 2, and light reflection at the interface between the third liquid crystal retardation film and the adhesive layer 2 can be suppressed.

[0127] The in-plane average refractive index of the adhesive layer 2 at a wavelength of 589 nm can be appropriately determined depending on the in-plane average refractive index of the adjacent third liquid crystal retardation film, the optical properties required of the optically anisotropic laminate, the in-plane average refractive index of the second liquid crystal retardation film, etc., but is preferably 1.40 to 1.65. When the in-plane average refractive index of the adhesive layer 2 is within the above range, it becomes easier to control the refractive index difference between the adhesive layer 2 and the third liquid crystal retardation film. Controlling the refractive index difference can suppress light reflection in the optically anisotropic laminate, and can effectively suppress reflection between the layers of external light taken in when the laminate is incorporated into an image display device and set to black display. From this perspective, the in-plane average refractive index of the adhesive layer 2 at a wavelength of 589 nm is more preferably 1.43 or more, even more preferably 1.45 or more, for example 1.47 or more, or more preferably 1.60 or less, even more preferably 1.54 or less, for example 1.50 or less.

[0128] In one embodiment of the present invention, the difference (absolute value difference: |n4-n5|) between the in-plane average refractive index of the adhesive layer 2 (hereinafter also referred to as "refractive index n4") and the in-plane average refractive index of the third liquid crystal retardation film (hereinafter also referred to as "refractive index n5") is preferably 0.15 or less, more preferably 0.12 or less, and even more preferably 0.10 or less. When the difference between the refractive index n4 of the adhesive layer 2 and the refractive index n5 of the third liquid crystal retardation film is equal to or less than the above-mentioned upper limit, the effect of suppressing light reflection at the interface between these two layers can be improved. From the viewpoint of suppressing light reflection and obtaining an excellent reflection suppression effect when incorporated into a display device, the smaller the difference, the more preferable.

[0129] In one embodiment of the present invention, the difference (absolute value difference: |n4-n3|) between the in-plane average refractive index n4 of the adhesive layer 2 and the in-plane average refractive index of the second liquid crystal retardation film (hereinafter also referred to as "refractive index n3") is preferably 0.15 or less, more preferably 0.12 or less, and even more preferably 0.10 or less. When the difference between the refractive index n4 of the adhesive layer 2 and the refractive index n3 of the second liquid crystal retardation film is equal to or less than the above-mentioned upper limit, the effect of suppressing light reflection at the interface between these two layers can be improved. From the viewpoint of suppressing light reflection and obtaining an excellent reflection suppression effect when incorporated into a display device, the smaller the difference, the more preferable.

[0130] The refractive indexes n4 and n5, and the difference between them, can be controlled by appropriately selecting the compositions of the third liquid crystal retardation film and the adhesive layer 2, particularly the types of compounds constituting each of these layers, their combinations, etc. In particular, by adjusting the refractive index of the adhesive layer 2, which does not have light absorption anisotropy, to approximate the in-plane average refractive index of the third liquid crystal retardation film, it is possible to effectively suppress light reflection occurring at the interface between the third liquid crystal retardation film and the adhesive layer 2 while ensuring high optical properties required of a retardation film.

[0131] The thickness of the third liquid crystal retardation film can be appropriately determined depending on the type of the third liquid crystal retardation film, the optical properties required for the optically anisotropic laminate, etc. In one embodiment of the present invention, the thickness may be, for example, 0.1 to 3 μm, preferably 0.1 to 2.5 μm, more preferably 0.3 to 2.5 μm, and even more preferably 0.5 to 2 μm. When the thickness of the third liquid crystal retardation film is within the above range, the occurrence of cloudy unevenness in the third liquid crystal retardation film is easily suppressed.

[0132] The thickness of the adhesive layer 2 is preferably 0.5 to 10 μm. The thicker the adhesive layer 2, the higher the effect of suppressing interference unevenness in the laminate tends to be. Therefore, from the viewpoint of interference unevenness, it is advantageous for the adhesive layer 2 to be thicker, and for example, the thickness is more preferably 0.5 to 8 μm, and even more preferably 0.5 to 5 μm.

[0133] When a third liquid crystal retardation film is included, the liquid crystal molecular alignment direction of the third liquid crystal retardation film is usually determined according to the optical properties required for the optically anisotropic laminate in relation to the first liquid crystal retardation film and the second liquid crystal retardation film. For example, when the first liquid crystal retardation film and the second liquid crystal retardation film are both horizontally aligned rod-shaped liquid crystal cured retardation films functioning as a quarter-wave plate, and the third liquid crystal retardation film includes a horizontally aligned rod-shaped liquid crystal cured retardation film functioning as a quarter-wave plate, an optically anisotropic laminate having a retardation function can be obtained by laminating them so that the liquid crystal molecular alignment direction of the third liquid crystal retardation film is at an angle of 60±5° with respect to the liquid crystal molecular alignment of the first liquid crystal retardation film or the second liquid crystal retardation film.

[0134] The third liquid crystal retardation film is preferably a cured liquid crystal film formed by aligning a polymerizable liquid crystal compound. The third liquid crystal retardation film may be a cured liquid crystal film such as those exemplified above for the first liquid crystal retardation film and the second liquid crystal retardation film. The third liquid crystal retardation film can be appropriately selected in relation to the first liquid crystal retardation film and the second liquid crystal retardation film depending on the optical properties desired for the optically anisotropic laminate. The third liquid crystal retardation film may also be, for example, a film formed by immobilizing a rod-shaped polymerizable liquid crystal compound aligned perpendicular to the film surface. Such a liquid crystal retardation film can be obtained by orienting the rod-shaped polymerizable liquid crystal compound so that its long axis is perpendicular to the in-plane direction of the liquid crystal retardation film. The polymerizable liquid crystal compound forming the vertically aligned rod-shaped cured liquid crystal retardation film can be appropriately selected from polymerizable liquid crystal compounds known in the art. Specific examples include compounds described in International Publication No. 2018 / 003416 and the like, and can be produced according to the methods described in these documents.

[0135] The third liquid crystal retardation film may be formed of a liquid crystal cured film alone or may be formed to include an alignment film. When the alignment film is included, the alignment film may be the same as those exemplified above as those included in the first liquid crystal retardation film, etc., and may be appropriately selected depending on the configuration of the third liquid crystal retardation film, etc.

[0136] Examples of the pressure-sensitive adhesive layer 2 include layers formed from pressure-sensitive adhesives, active energy ray-curable adhesives, water-based adhesives, organic solvent-based adhesives, and solventless adhesives, each of which contains as a main component a resin such as a (meth)acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinyl ether-based resin, as described above with respect to the pressure-sensitive adhesive layer 1. Among these, pressure-sensitive adhesives or active energy ray-curable adhesives are preferred from the viewpoints of transparency, adhesive strength, removability, weather resistance, heat resistance, and the like, and layers formed from pressure-sensitive adhesives are more preferred.

[0137] <Circular polarizer> In one embodiment of the present invention, the optically anisotropic laminate may include a polarizing plate on the surface of the first liquid crystal retardation film opposite to the adhesive layer 1, with the adhesive layer 3 interposed therebetween. The polarizing plate here generally refers to a film that transmits light vibrating in the transmission axis direction but blocks polarized light vibrating perpendicularly thereto, thereby functioning as a polarizing film that extracts linearly polarized light from incident natural light. By including such a polarizing plate, the optically anisotropic laminate functions as a circular polarizing plate. Therefore, the present invention also relates to a circular polarizing plate that includes a polarizing plate on the surface of the first liquid crystal retardation film opposite to the adhesive layer 1, with the adhesive layer 3 interposed therebetween. When a polarizing plate is included, it is preferable that the polarizing plate be laminated adjacent to the surface of the first liquid crystal retardation film opposite to the adhesive layer 1, with the adhesive layer 3 interposed therebetween.

[0138] In the present invention, the in-plane average refractive index at a wavelength of 589 nm of the adhesive layer 3 located between the first liquid crystal retardation film and the polarizing plate can be appropriately determined depending on the in-plane average refractive index of the adjacent layer, the optical properties required of the optically anisotropic laminate, the configuration of the polarizing plate to be laminated, etc., but is preferably 1.45 to 1.60. When the in-plane average refractive index of the adhesive layer 3 is within the above range, it becomes easier to control the refractive index difference between the adhesive layer 3 and the first liquid crystal retardation film and the refractive index difference between the adhesive layer 3 and the polarizing plate. By reducing these refractive index differences, light reflection in the optically anisotropic laminate can be suppressed, and when the laminate is incorporated into an image display device and a black display is set, reflection between the layers of external light taken in can be effectively suppressed. In particular, it is preferable to control the in-plane average refractive index at a wavelength of 589 nm of the adhesive layer 3 to be within a range between the refractive index of the layer adjacent to the polarizing plate side of the adhesive layer (e.g., a polarizer protective film described below) and the refractive index of the first liquid crystal cured film. It is more preferable to control the refractive index within this range closer to the refractive index of the layer adjacent to the polarizing plate side of the adhesive layer. By controlling the refractive index within such a range, the above-mentioned light reflection suppression effect can be excellent and the effect of suppressing interference unevenness can also be enhanced. From this viewpoint, the in-plane average refractive index at a wavelength of 589 nm of the pressure-sensitive adhesive layer 3 is more preferably 1.58 or less, even more preferably 1.55 or less, for example, may be 1.55 or less, more preferably 1.51 or less, even more preferably 1.50 or less.

[0139] In one embodiment of the present invention, the difference (absolute value difference: |n6-n7|) between the in-plane average refractive index of the adhesive layer 3 (hereinafter also referred to as "refractive index n6") and the in-plane average refractive index of the polarizing plate (hereinafter also referred to as "refractive index n7") is preferably 0.10 or less, more preferably 0.09 or less, and in some cases, for example, may be 0.03 or less, and ideally is 0. When the difference between the refractive index n6 of the adhesive layer 3 and the refractive index n6 of the polarizing plate is equal to or less than the above-mentioned upper limit, the effect of suppressing light reflection at the interface between these two layers can be improved. Note that, when the polarizing plate is a multilayered layer, the in-plane average refractive index of the polarizing plate means the in-plane average refractive index of the layer located on the adhesive layer 3 side. That is, when the polarizing plate includes a polarizer and a protective film as described below, and when the protective film is located on the adhesive layer 3 side, it is preferable that the in-plane average refractive index of the protective film satisfies the above-mentioned relationship.

[0140] In one embodiment of the present invention, the difference (absolute value difference: |n6-n2|) between the in-plane average refractive index n6 of the adhesive layer 3 and the in-plane average refractive index n2 of the first liquid crystal retardation film is preferably 0.10 or less, more preferably 0.08 or less, and usually 0.01 or more. When the difference between the refractive index n6 of the adhesive layer 3 and the refractive index n2 of the first liquid crystal retardation film is not more than the above-mentioned upper limit, the effect of suppressing light reflection at the interface between these two layers can be improved. In particular, the refractive indices n6, n7, and n2 satisfy the following relationship: n7≦n6 <n2 When the above relationship of refractive index difference is satisfied and the above relationship of refractive index difference is satisfied, the effect of the present invention is more likely to be obtained.

[0141] In one embodiment of the present invention, the polarizing plate has an in-plane average refractive index at a wavelength of 589 nm of, for example, preferably 1.45 to 1.55, more preferably 1.45 to 1.55. When the in-plane average refractive index of the polarizing plate is within the above range, it is easy to control the refractive index difference in relation to the adhesive layer 3, and light reflection at the interface between the polarizing plate and the adhesive layer 3 can be suppressed.

[0142] The refractive indexes n6, n7, n2, and the difference therebetween can be controlled by appropriately selecting the composition of the pressure-sensitive adhesive layer 3, the configuration of the polarizing plate, particularly the types of compounds constituting each of these layers, their combinations, etc. In particular, by adjusting the refractive index of the pressure-sensitive adhesive layer 3, which does not have light absorption anisotropy, to approximate the in-plane average refractive index of a protective film included in the polarizing plate, for example, it is possible to effectively suppress the occurrence of light reflection and interference unevenness in the circular polarizing plate while ensuring the high optical properties required for a polarizing plate or a retardation film.

[0143] Examples of adhesives constituting the adhesive layer 3 include pressure-sensitive adhesives capable of forming the adhesive layers 1 and 2, active energy ray-curable adhesives, water-based adhesives, organic solvent-based adhesives, and solventless adhesives. Among these, from the viewpoints of making it easier to control the refractive index of the adhesive layer 3 within the above-mentioned specific range and enhancing the effect of suppressing light reflection at the interfaces between the adjacent polarizing plate and liquid crystal retardation film, an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound is preferred, and an ultraviolet-curable adhesive layer containing a (meth)acrylic compound is more preferred. In particular, when the adhesive layer is an ultraviolet-curable adhesive layer containing a (meth)acrylic compound, in addition to the light reflection suppression effect, the effect of suppressing interference unevenness in the optically anisotropic laminate can be enhanced.

[0144] The thickness of the adhesive layer 3 is preferably 0.1 to 3 μm. The thicker the adhesive layer 3, the greater the effect of suppressing interference unevenness in the laminate tends to be. Therefore, from the viewpoint of interference unevenness, it is advantageous for the adhesive layer 3 to be thicker. On the other hand, in the present invention, for example, by controlling the in-plane average refractive index of the adhesive layer 3 within the above-mentioned range, it is possible to obtain an optically anisotropic laminate that is excellent in the effect of suppressing interference unevenness even with a thin adhesive layer 3, and also to obtain an optically anisotropic laminate that is more excellent in terms of light reflection effect. Therefore, in one embodiment of the present invention, the thickness of the adhesive layer 3 is preferably 0.1 to 3 μm, more preferably 0.1 to 2.5 μm, even more preferably 0.3 to 2.5 μm, and particularly preferably 0.5 to 2 μm.

[0145] The polarizing plate is, for example, a film having a polarizing function, and examples thereof include a stretched film having adsorbed thereon a dye having absorption anisotropy, and a film including a film coated with a dye having absorption anisotropy as a polarizer. Examples of dyes having absorption anisotropy include dichroic dyes. Films known in the art having such a polarizing function can be appropriately selected and used. Specific examples include the polarizing films described in International Publication No. 2018 / 03416 and the like, which can be produced according to the methods described in these documents.

[0146] In one embodiment of the present invention, the polarizing plate preferably has a protective film on at least one surface of the polarizer, and more preferably has a protective film on the surface of the polarizer facing the adhesive layer 3. In this case, the in-plane average refractive index of the protective film at a wavelength of 589 nm is, for example, preferably 1.45 to 1.55, more preferably 1.45 to 1.52. When the in-plane average refractive index of the protective film is within the above range, it is easy to control the refractive index difference in relation to the adhesive layer 3, and light reflection at the interface between the protective film and the adhesive layer 3 can be suppressed.

[0147] The protective film can be, for example, a resin film substrate conventionally known in the field of optical films. By selecting the type of resin, the refractive index of the protective film can be controlled within an appropriate range in relation to the pressure-sensitive adhesive layer 3. In the present invention, the resin film is preferably a transparent resin film, since it is usually incorporated into a display device as one of the constituent layers of a polarizing plate. A transparent resin film means a resin film that is transparent enough to transmit light, particularly visible light, and transparency refers to a property in which the transmittance for light rays with wavelengths of 380 to 780 nm is 80% or more. Examples of resins constituting such resin films include polyolefin-based resins such as polyethylene and polypropylene; cycloolefin-based resins such as norbornene-based polymers; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; poly(meth)acrylic acid-based resins such as (meth)acrylic acid and polymethyl(meth)acrylate; cellulose ester-based resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate-based resins; polystyrene-based resins; polyarylate-based resins; polysulfone-based resins; polyethersulfone-based resins; polyamide-based resins; polyimide-based resins; polyether ketone-based resins; polyphenylene sulfide-based resins; polyphenylene oxide-based resins, and mixtures thereof. These may be used alone or in combination of two or more. Such resins can be formed into a film by known means such as solvent casting or melt extrusion to form a resin film substrate. Commercially available products may also be used as the film substrate or the resin constituting the film substrate.

[0148] The protective film is preferably a cellulose ester resin film, a cycloolefin resin film, a polyester resin film, or a poly(meth)acrylic acid resin film, more preferably a cellulose ester resin film or a cycloolefin resin film. These resin films are easy to control the refractive index difference in relation to the adhesive layer having the specific refractive index, and can more effectively suppress light reflection at the interface between the resin film and the adhesive layer. The protective film may be subjected to a surface treatment.

[0149] The thickness of the protective film is not particularly limited and is, for example, 5 to 100 μm, and preferably 10 to 50 μm. When the thickness of the protective film is within the above range, it is possible to obtain a circular polarizing plate that not only functions as a protective film but also is less likely to cause light reflection in relation to the adhesive layer 3 and is excellent in the reflection suppression effect during black display.

[0150] When a polarizing plate is laminated on a laminate including a first liquid crystal cured film, it is preferable to laminate the polarizing plate so that the angle between the transmission axis of the polarizing plate (polarizer) and the slow axis (optical axis) of the first liquid crystal retardation film is 15±5°. By laminating the polarizing plate so that the angle between the slow axis (optical axis) of the first liquid crystal retardation film and the transmission axis of the polarizing plate (polarizer) is set in this way, it is possible to obtain the function of a circular polarizing plate.

[0151] The optically anisotropic laminate and circular polarizing plate of the present invention are unlikely to cause cloudy unevenness or interference unevenness and have excellent light reflection suppression properties, so that high optical performance can be expected. Therefore, the optically anisotropic laminate and circular polarizing plate of the present invention are suitable as components of various display devices. A display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (e.g., field emission displays (FEDs) and surface field emission displays (SEDs)), electronic paper (display devices using electronic ink or electrophoretic elements), plasma display devices, projection display devices (e.g., grating light valve (GLV) display devices and display devices having digital micromirror devices (DMDs)), and piezoelectric ceramic displays. Liquid crystal display devices include transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, and reflective liquid crystal display devices. The present invention includes any of various display devices, such as direct-view liquid crystal display devices and projection-type liquid crystal display devices. These display devices may be display devices that display two-dimensional images or stereoscopic display devices that display three-dimensional images. In particular, the optically anisotropic laminate and circular polarizer of the present invention can be suitably used in organic electroluminescence (EL) display devices and inorganic electroluminescence (EL) display devices, and can also be suitably used in liquid crystal display devices and touch panel display devices. These display devices can exhibit good image display characteristics because the optically anisotropic laminate and circular polarizer of the present invention have excellent reflective appearance effects and high visibility. [Example]

[0152] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, "%" and "parts" mean "% by mass" and "parts by mass" unless otherwise specified.

[0153] 1.Measuring methods for various physical properties (1) Refractive index of adhesive layer The prepared adhesive was applied to one side of a stretched norbornene resin film ("ZEONORFILM" manufactured by Nippon Zeon Co., Ltd.) using a bar coater (manufactured by Daiichi Rika Co., Ltd.) so that the thickness after ultraviolet irradiation would be approximately 30 μm. An ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to apply an integrated light dose of 600 mJ / cm.2 The norbornene-based resin film was peeled off from the cured product, and the refractive index (589 nm) of the cured product layer was measured at 25°C using a multi-wavelength Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.).

[0154] (2) Refractive index of the adhesive layer After peeling the separator film from the adhesive layers 1 and 2 formed on the separator film, the refractive index (589 nm) of the adhesive layers 1 and 2 was measured using a multi-wavelength Abbe refractometer ("DR-M2" manufactured by Atago Co., Ltd.) in an environment of 25°C.

[0155] (3) Refractive index of the retardation film The refractive index of the retardation film was measured by measuring the in-plane average refractive index (589 nm) using an ellipsometer M-220 manufactured by JASCO Corporation in a state where the film was attached to glass via an adhesive.

[0156] (5) Measurement of storage modulus of adhesive layer The storage modulus of the adhesive layer at temperatures of 23°C and 80°C was measured using a viscoelasticity measuring device (MCR-301, Anton Paar). After cutting the adhesive sheet into a piece 30 mm wide x 30 mm long, the separator was peeled off, and multiple sheets were stacked to a thickness of 200 μm and attached to a measurement stage. After adhering to a parallel plate with a diameter of 25 mm, measurements were carried out in a temperature range of 20°C to 85°C under conditions of a frequency of 1.0 Hz, a deformation of 1%, and a heating rate of 10°C / min, and the storage modulus G' at temperatures of 23°C and 80°C was determined.

[0157] 2. Preparation of retardation film (1) Preparation of retardation film 1 (i) Preparation of composition for forming alignment film 1 Alignment material 1 (weight average molecular weight: 50,000, m:n = 50:50) represented by the following chemical formula was prepared in accordance with the method described in JP 2021-196514 A. Two parts by mass of this alignment material 1 was mixed with 98 parts by mass of cyclopentanone (solvent), and the resulting mixture was stirred at 80°C for one hour to prepare a composition for forming alignment film 1.

[0158] Oriented material 1: TIFF2026005756000001.tif58121

[0159] (ii) Preparation of polymerizable liquid crystal compound (A1) and polymerizable liquid crystal compound (A2) Polymerizable liquid crystal compound (A1) and polymerizable liquid crystal compound (A2) represented by the following chemical formula were prepared. The polymerizable liquid crystal compound (A1) was prepared in the same manner as the method described in JP-A-2019-003177, and the polymerizable liquid crystal compound (A2) was prepared in the same manner as the method described in JP-A-2009-173893.

[0160] Polymerizable liquid crystal compound (A1): TIFF2026005756000002.tif46150 Polymerizable liquid crystal compound (A2): TIFF2026005756000003.tif17124

[0161] A solution was obtained by dissolving 1 mg of polymerizable liquid crystal compound (A1) in 10 mL of chloroform. The obtained solution was placed in a measurement cell with an optical path length of 1 cm to prepare a measurement sample. This measurement sample was then set in an ultraviolet-visible spectrophotometer (Shimadzu Corporation, "UV-2450") to measure the absorption spectrum. The wavelength at which the maximum absorbance was obtained was read from the obtained absorption spectrum, and the maximum absorption wavelength λ in the wavelength range of 300 to 400 nm was found to be 1. max was 356 nm.

[0162] (iii) Preparation of retardation film-forming composition 1 A polymerizable liquid crystal compound (A1) and a polymerizable liquid crystal compound (A2) were mixed in a mass ratio of 90:10 to obtain a mixture. To 100 parts by mass of the obtained mixture, 0.1 parts by mass of a leveling agent (BM Chemie's "BYK-361N") and 6 parts by mass of a photopolymerization initiator (BASF Japan's "IRG369") were added. Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solids concentration became 13% by mass. The mixture was stirred at 80°C for 1 hour to prepare a retardation film-forming composition 1.

[0163] (iv) Preparation of film with retardation film 1 The composition for forming the alignment film 1 obtained above was applied to a biaxially stretched polyethylene terephthalate (PET) film ("Diafoil" manufactured by Mitsubishi Plastics, Inc.) as the substrate A using a bar coater to obtain a coating film, and the obtained coating film was dried at 120°C for 2 minutes and then cooled to room temperature to form a dry coating. Thereafter, using a UV irradiation device ("SPOT CURE SP-9" manufactured by Ushio Inc.), an integrated light dose of 100 mJ / cm2 at a wavelength of 313 nm was applied to this dry coating. 2 The film was irradiated with polarized ultraviolet light so as to obtain an alignment film 1. The thickness of this alignment film 1 was measured using an ellipsometer ("M-220" manufactured by Nippon Bunkosha) and was found to be 100 nm.

[0164] The retardation film-forming composition 1 obtained above was applied onto the obtained alignment film 1 using a bar coater to form a coating film. This coating film was heated and dried at 120°C for 2 minutes, and then cooled to room temperature to obtain a dried film. Next, a high-pressure mercury lamp ("Uniquer VB-15201BY-A" manufactured by Ushio Inc.) was used to dry the film under a nitrogen atmosphere at 365 nm, with an integrated light amount (exposure amount) of 500 mJ / cm. 2The dried film was irradiated with ultraviolet light so that a retardation film 1 was formed on the alignment film 1, thereby obtaining a film with the retardation film 1. The retardation film 1 constituting the film with the retardation film 1 is a retardation film in which the polymerizable liquid crystal compound is cured in a state where it is aligned horizontally relative to the plane of the substrate. The layer structure of the film with the retardation film 1 is substrate A / alignment film 1 / retardation film 1. The film thickness of the retardation film 1 measured using a laser microscope (Olympus "LEXT OLS4100") was 2.0 μm.

[0165] The retardation film-coated film obtained above was subjected to corona treatment on the side of the retardation film, and then laminated to a glass plate via adhesive sheet 1. Substrate A / alignment film 1 was peeled off and removed to obtain a measurement sample with a retardation film 1 / adhesive sheet 1 / glass plate configuration. The in-plane retardation values ​​of this measurement sample were measured using a retardation measurement device (Oji Scientific Instruments, "KOBRA-WR"). The in-plane retardation values ​​for light with wavelengths of 450 nm, 550 nm, and 650 nm were calculated using Cauchy's dispersion formula from the in-plane retardation measurements for light with wavelengths of 448.2 nm, 498.6 nm, 548.4 nm, 587.3 nm, 628.7 nm, and 748.6 nm. The in-plane retardation Re(450) at a wavelength of 450 nm was 122 nm, the in-plane retardation Re(550) at a wavelength of 550 nm was 140 nm, and the in-plane retardation Re(650) at a wavelength of 650 nm was 144 nm. The relationship between the in-plane retardation at each wavelength was as follows: Re(450) / Re(550)=0.87 Re(650) / Re(550)=1.03 [In the formula, Re(450) represents the in-plane retardation value for light with a wavelength of 450 nm, Re(550) represents the in-plane retardation value for light with a wavelength of 550 nm, and Re(650) represents the in-plane retardation value for light with a wavelength of 650 nm.]

[0166] (2) Preparation of retardation film 2 A film with a retardation film 2 was produced in the same manner as in the production of the retardation film 1, except that the retardation film-forming composition 1 was applied so that the thickness after ultraviolet light irradiation would be 4.2 μm. The retardation values ​​of the retardation film 2 obtained were measured in the same manner as in the measurement of the retardation value of the retardation film 1, and found to be Re(550)=284 nm and Rth(550)=142 nm. Furthermore, the retardation values ​​at wavelengths of 450 nm and 650 nm were measured, and found to be Re(450)=247 nm and Re(650)=290 nm. The relationship between the in-plane retardation values ​​at each wavelength was as follows: Re(450) / Re(550)=0.87 Re(650) / Re(550)=1.02 [In the formula, Re(450) represents the in-plane retardation value for light with a wavelength of 450 nm, Re(550) represents the in-plane retardation value for light with a wavelength of 550 nm, and Re(650) represents the in-plane retardation value for light with a wavelength of 650 nm.]

[0167] (3) Preparation of Retardation Film 3 and Retardation Film 4 (i) Preparation of composition for forming alignment film 2 Water was added to commercially available polyvinyl alcohol (polyvinyl alcohol 1000 fully saponified type, manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was heated at 100° C. for 1 hour to obtain a composition for forming the alignment film 2.

[0168] (ii) Preparation of polymerizable liquid crystal compound (A3) and polymerizable liquid crystal compound (A4) Polymerizable liquid crystal compounds (A3) and (A4) having the structures shown below were prepared in the same manner as described in JP-A-2010-244038.

[0169] Polymerizable liquid crystal compound (A3): TIFF2026005756000004.tif99150

[0170] Polymerizable liquid crystal compound (A4): TIFF2026005756000005.tif92150

[0171] (iii) Preparation of retardation film-forming composition 2 A mixture was obtained by mixing polymerizable liquid crystal compound (A3) and polymerizable liquid crystal compound (A4) in a mass ratio of 80:20. To 100 parts by mass of the resulting mixture, a leveling agent "Megafac F-556" (manufactured by DIC Corporation), a photopolymerization initiator "Omnirad907" (manufactured by IGM Resin BV), and an ionic compound (B) were added. Furthermore, propylene glycol monomethyl ether acetate (PEGMEA) was added, and the mixture was stirred at a temperature of 80°C for 1 hour to prepare a retardation film-forming composition 2. The amounts of each component added are shown in Table 1 below.

[0172] [Table 1]

[0173] Ionic compounds (B): TIFF2026005756000007.tif52150

[0174] (iv) Preparation of retardation film-forming composition 3 To the polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF Japan Ltd.), a leveling agent "BYK-361N" (manufactured by BYK-Chemie) and a photopolymerization initiator "Omnirad907" (manufactured by IGM Resin BV) were added. Further, propylene glycol monomethyl ether acetate (PEGMEA) was added, and the mixture was stirred at a temperature of 80°C for 1 hour to prepare retardation film-forming composition 3. The amount of each component added is as shown in Table 2 below.

[0175] [Table 2]

[0176] Polymerizable liquid crystal compound LC242: TIFF2026005756000009.tif27150

[0177] (v) Preparation of film with retardation film 3 The composition for forming the alignment film 2 was applied to a triacetyl cellulose film (TAC) (KC4UY, manufactured by Konica Minolta, Inc.) cut into a rectangle as the substrate B, to form a coating film having a thickness of 100 nm after heat drying. The surface of the obtained coating film was subjected to a rubbing treatment, and the composition for forming the retardation film 2 was applied thereon using a bar coater. The obtained coating film was dried at 100°C for 1 minute and then cooled to room temperature to obtain a dried film. Next, a high-pressure mercury lamp (Uniqure VB-15201BY-A, manufactured by Ushio Inc.) was used to expose the film to light at a dose of 1000 mJ / cm under a nitrogen atmosphere. 2 The dried film was irradiated with ultraviolet light (365 nm standard) to form a retardation film 3 in which the polymerizable liquid crystal compound was cured in a state of being aligned horizontally relative to the substrate plane, and a film with a retardation film 3 was obtained, consisting of substrate B / alignment film 2 / retardation film 3 (horizontally aligned liquid crystal cured film). The thickness of the obtained retardation film 3 was measured using a laser microscope and found to be 1.0 μm. The in-plane retardation value was measured using a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. As a result, the in-plane retardation value at a wavelength of 550 nm was Re(550) = 135 nm, and the in-plane retardation value at a wavelength of 450 nm was Re(450) = 146 nm. Note that the retardation value of substrate B (TAC) at a wavelength of 550 nm was approximately 0, so this did not affect the optical properties.

[0178] (vi) Preparation of film with retardation film 4 The composition for forming the alignment film 1 was applied to a triacetyl cellulose film (TAC) (KC4UY, manufactured by Konica Minolta, Inc.) cut into a rectangle as the substrate B. The resulting coating film was dried at 120°C for 2 minutes and then cooled to room temperature to form a dry film. Furthermore, using a UV irradiation device, 100 mJ of polarized ultraviolet light (313 nm standard) was continuously irradiated to form a 100 nm alignment film 1. On top of this, the composition 3 for forming the retardation film was applied using a bar coater. The resulting coating film was dried at 100°C for 1 minute and then cooled to room temperature to obtain a dry film. Next, using a high-pressure mercury lamp, the film was exposed to light at an exposure dose of 1000 mJ / cm under a nitrogen atmosphere. 2The dried film was continuously irradiated with ultraviolet light (365 nm standard) to form a retardation film 4 in which the polymerizable liquid crystal compound was cured in a state of being aligned horizontally relative to the substrate plane, resulting in a film with a retardation film 4 consisting of substrate B / alignment film 1 / retardation film 3. The thickness of the obtained retardation film 4 was measured using a laser microscope and found to be 1.0 μm. The in-plane retardation value was measured using a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. The in-plane retardation value at a wavelength of 550 nm was Re(550) = 142 nm, and the in-plane retardation value at a wavelength of 450 nm was Re(450) = 153.4 nm. Note that the retardation value of substrate B (TAC) at a wavelength of 550 nm was approximately 0, so there was no effect on the optical properties.

[0179] 3. Adhesive Preparation (i) Preparation of Adhesive 1 The following components were blended and mixed, and then degassed to prepare adhesive 1. [Cationic polymerizable compounds] 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation): 70 parts by mass Neopentyl glycol diglycidyl ether (product name: EX-211, manufactured by Nagase ChemteX Corporation): 20 parts by mass 2-Ethylhexyl glycidyl ether (product name: EX-121, manufactured by Nagase ChemteX Corporation): 10 parts by mass [Cationic photopolymerization initiator] Cationic polymerization initiator (product name: CPI-100P_50% solution propylene carbonate solution, manufactured by San-Apro Co., Ltd.): 4.5 parts by mass (actual solid content: 2.25 parts by mass) [Photosensitizer] 1,4-diethoxynaphthalene: 2 parts by mass

[0180] The refractive index of Adhesive 1 for light with a wavelength of 589 nm at a temperature of 23° C. was 1.51.

[0181] (ii) Preparation of Adhesive 2 The following components were blended and mixed, and then degassed to prepare adhesive 2. [Cationic polymerizable compounds] Neopentyl glycol diglycidyl ether (product name: EX-211L, manufactured by Nagase ChemteX Corporation): 30 parts by mass 3-Ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (trade name: OXT-221, manufactured by Toagosei Co., Ltd.): 13 parts by mass Bisphenol A epoxy resin (product name: EP-4100E, ADEKA Corporation, viscosity 13 Pa·s (temperature 25°C)): 45 parts by weight ·Aromatic-containing oxetane compound (product name: TCM-104, manufactured by TRONLY): 12 parts by mass [Cationic photopolymerization initiator] CPI-100P, manufactured by San-Apro Co., Ltd., 50% propylene carbonate solution: 2.25 parts by weight (solid content) [Photosensitizer] 1,4-diethoxynaphthalene: 1 part by mass

[0182] The refractive index of adhesive 2 for light with a wavelength of 589 nm at a temperature of 23° C. was 1.54.

[0183] (iii) Preparation of Adhesive 3 The following components were blended and mixed, and then degassed to prepare adhesive 3. [Radical polymerizable compounds] 1,6-Hexanediol diacrylate (product name: A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.): 20 parts by mass Phenoxy polyethylene glycol acrylate (product name: AMP-20GY, manufactured by Shin-Nakamura Chemical Co., Ltd.): 80 parts by mass [Photoradical polymerization initiator] Radical polymerization initiator (product name: Omnirad819, manufactured by IGM RESINS BV): 3.0 parts by mass

[0184] The refractive index of adhesive 3 for light with a wavelength of 589 nm at a temperature of 23° C. was 1.53.

[0185] (iv) Preparation of Adhesive 4 The following components were blended and mixed, and then degassed to prepare adhesive 4. [Radical polymerizable compounds] 1,6-Hexanediol diacrylate (product name: A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.): 40 parts by mass Fluorene-based bifunctional acrylate monomer (product name: OGSOL EA-0200, manufactured by Osaka Gas Chemicals Co., Ltd.): 80 parts by mass [Photoradical polymerization initiator] Radical polymerization initiator (product name: Omnirad819, manufactured by IGM RESINS BV): 3.0 parts by mass

[0186] The refractive index of adhesive 4 for light with a wavelength of 589 nm at a temperature of 23° C. was 1.58.

[0187] (v) Preparation of Adhesive 5 The following components were blended and mixed, and then degassed to prepare adhesive 5. [Radical polymerizable compounds] 1,6-Hexanediol diacrylate (product name: A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.): 40 parts by mass Fluorene-based bifunctional acrylate monomer (product name: OGSOL EA-0200, manufactured by Osaka Gas Chemicals Co., Ltd.): 80 parts by mass [Photoradical polymerization initiator] Radical polymerization initiator (product name: Omnirad819, manufactured by IGM RESINS BV): 3.0 parts by mass

[0188] The refractive index of adhesive 5 for light with a wavelength of 589 nm at a temperature of 23° C. was 1.62.

[0189] 4. Fabrication of Linear Polarizers (1) Preparation of polarizer A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2400, and a degree of saponification of 99% or more was uniaxially stretched to a stretching ratio of 4.5 times on a heated roll, and while maintaining tension, was immersed for 60 seconds in a dye bath at 28°C containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water.

[0190] The film was then 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. The film was then 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. The film was then washed with 10°C pure water and dried to obtain a polarizer. The polarizer had a thickness of 8 μm and a boron content of 4.3% by mass.

[0191] (2) Preparation of water-based adhesive An aqueous polyvinyl alcohol solution was prepared by dissolving 3 parts by mass of carboxyl-modified polyvinyl alcohol ("KL-318" manufactured by Kuraray Co., Ltd.) in 100 parts by mass of water. A water-soluble polyamide epoxy resin ("Sumirez Resin 650(30)" manufactured by Taoka Chemical Co., Ltd., solids concentration 30% by mass) was mixed with the resulting aqueous solution in a ratio of 1.5 parts by mass per 100 parts by mass of water to obtain an aqueous adhesive.

[0192] (3) Preparation of linear polarizer A hard coat (HC) layer-attached cyclic polyolefin resin film (HC-COP) as the first protective film and a triacetyl cellulose (TAC) film as the second protective film were laminated to both sides of the polarizer prepared above using a roll laminator via the aqueous adhesive obtained above. After lamination, the film was dried at 80°C for 3 minutes. The resulting roll was cut into a rectangle with the longitudinal direction aligned with the absorption axis of the PVA, yielding a linear polarizing plate 10 in which protective films were laminated on both sides of the polarizer. The linear polarizing plate 10 had a layer structure of first protective film / adhesive layer / polarizer / adhesive layer / second protective film. The second protective film had an in-plane average refractive index of 1.49 for light with a wavelength of 589 nm. The refractive index of the second protective film was measured in a 25° C. environment using a multi-wavelength Abbe refractometer ("DR-M2" manufactured by Atago Co., Ltd.).

[0193] 5. Preparation of adhesive layer (1) Preparation of adhesive layer 1 (acrylic adhesive layer) (i) Preparation of acrylic resin solution 1 A reaction vessel equipped with a condenser, nitrogen inlet, 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 air inside the vessel was purged with nitrogen gas to remove oxygen, and the internal temperature was raised to 55°C. A solution of 0.12 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was then added in its entirety. After the addition of the polymerization initiator, the temperature was maintained for 1 hour. Ethyl acetate was then continuously added to the reaction vessel at a rate of 17.3 parts / hour while maintaining the internal temperature at 54-56°C. The addition of ethyl acetate was stopped when the (meth)acrylic resin concentration reached 35% by mass, and the mixture was maintained at this temperature for a further 6 hours. Finally, ethyl acetate was added to adjust the (meth)acrylic resin concentration to 20% by mass, preparing Acrylic Resin Solution 1. The resulting acrylic resin had a weight average molecular weight Mw of 1.7 million and a molecular weight distribution Mw / Mn of 3.9. Mw and Mn were measured using a GPC system with a TSKgel GMH column manufactured by Tosoh Corporation. HR Two "-H(S)" tubes were connected in series, and tetrahydrofuran was used as the eluent. Measurements were performed in terms of standard polystyrene under the following conditions: sample concentration 2 mg / mL, sample introduction volume 100 μL, temperature 40°C, and flow rate 1 mL / min.

[0194] (ii) Preparation of Pressure-Sensitive Adhesive Composition 1 Based on 80 parts of the solid content of the acrylic resin solution 1 obtained above, 20 parts (solid content) of a bifunctional acrylate (obtained from Shin-Nakamura Chemical Co., Ltd.; product number "A-DOG"), 2.5 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 0.3 parts 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 an adhesive composition 1. A-DOG is a diacrylate of an acetal compound of hydroxypivalaldehyde and trimethylolpropane and has the structure of the following formula.

[0195] TIFF2026005756000010.tif33150

[0196] (iii) Preparation of the adhesive layer 1 The adhesive composition 1 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 "PLZ-383030") using an applicator so that the thickness after drying was 5 μm, and dried at 100 °C for 1 minute to prepare an adhesive layer (adhesive sheet). Next, the surface of the obtained adhesive layer on the side 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 "PLR-381031"). Subsequently, ultraviolet rays were irradiated under the following conditions to prepare the adhesive layer 1. The storage elastic modulus of the obtained adhesive layer at a temperature of 23 °C was 0.13 MPa, the storage elastic modulus at a temperature of 80 °C was 0.054 MPa, and the refractive index with respect to light with a wavelength of 589 nm was 1.48.

[0197] <UV irradiation conditions> · Using a Fusion UV lamp system (manufactured by Fusion UV Systems) and an H bulb · Integrated light quantity of UVA in the UV wavelength region: 250 mJ / cm2 (Measurement equipment: Measurements taken using FusionUV's UV Power Puck II)

[0198] (1) Preparation of adhesive layer 2 (acrylic adhesive layer) (i) Preparation of acrylic resin solution 2 A reaction vessel equipped with a condenser, nitrogen inlet, thermometer, and stirrer was charged with a mixture of 81.8 parts ethyl acetate, 90.0 parts butyl acrylate, 5.0 parts methyl acrylate, and 5.0 parts acrylic acid. The air in the vessel was purged with nitrogen gas to remove oxygen, and the internal temperature was raised to 55°C. A solution of 0.15 parts azobisisobutyronitrile (polymerization initiator) in 10 parts ethyl acetate was then added in its entirety. After the addition of the polymerization initiator, the temperature was maintained for 1 hour. Ethyl acetate was then continuously added to the reaction vessel at a rate of 17.3 parts / hour while maintaining the internal temperature at 54-56°C. When the (meth)acrylic resin concentration reached 35% by mass, the ethyl acetate addition was stopped. The temperature was maintained for 6 hours after the start of the ethyl acetate addition. Finally, ethyl acetate was added to adjust the (meth)acrylic resin concentration to 20% by mass, preparing Acrylic Resin Solution 2. The resulting acrylic resin had a weight average molecular weight Mw of 1.6 million and a molecular weight distribution Mw / Mn of 4.5. Mw and Mn were measured using a GPC system with a TSKgel GMH column manufactured by Tosoh Corporation. HR Two "-H(S)" tubes were connected in series, and tetrahydrofuran was used as the eluent. Measurements were performed in terms of standard polystyrene under the following conditions: sample concentration 2 mg / mL, sample introduction volume 100 μL, temperature 40°C, and flow rate 1 mL / min.

[0199] (ii) Preparation of Pressure-Sensitive Adhesive 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" (an ethyl acetate solution of a trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75% by mass)) and 0.2 parts of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KBM-403") were added, and ethyl acetate was further added to bring the solid content concentration to 13%, thereby obtaining adhesive composition 2.

[0200] (iii) Preparation of adhesive layer 2 The pressure-sensitive adhesive composition 2 prepared above was applied using an applicator to the release-treated surface of a release-treated polyethylene terephthalate film ("PLR-382190" available from Lintec Corporation) to a thickness after drying shown in Table 3, and the applied coating was dried at 100°C for 1 minute to produce a pressure-sensitive adhesive layer. The surface of the resulting pressure-sensitive adhesive layer opposite the separator film was then bonded to the release-treated surface of a release-treated polyethylene terephthalate film ("PET-251130" available from Lintec Corporation), followed by irradiation with ultraviolet light under the same conditions as those used to prepare pressure-sensitive adhesive layer 1, to produce pressure-sensitive adhesive layer 2. The resulting pressure-sensitive adhesive layer 2 had a storage modulus of 0.026 MPa at 23°C, a storage modulus of 0.019 MPa at 80°C, and a refractive index of 1.48 for light with a wavelength of 589 nm.

[0201] 6. Fabrication of Circular Polarizers (1) Example 1 The surface of the second protective film (TAC) of the linear polarizer obtained above was subjected to corona treatment on the retardation film 1 side of the first liquid crystal retardation film using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) under conditions of an output of 0.3 kW and a treatment speed of 3 m / min, and the film with retardation film 1 was adjusted to form a 15° angle with the transmission axis of the PVA of the linear polarizer, and then laminated to obtain a first liquid crystal retardation film-attached laminate. Thereafter, the substrate A / alignment film 1 was peeled from the obtained first liquid crystal retardation film-attached laminate, and the peeled surface was subjected to corona treatment under the same conditions as above. As a second liquid crystal retardation film, the film with retardation film 1 was corona treated on the retardation film 1 side in the same manner as above, and the film with retardation film 1 was adjusted to form a 15° angle with the transmission axis of the PVA, and then laminated to obtain a second liquid crystal retardation film-attached laminate. Furthermore, the substrate A was peeled off from the obtained second liquid crystal retardation film-attached laminate, and the peeled surface was subjected to corona treatment under the same conditions as above. As a third liquid crystal retardation film, the retardation film 1-attached film, which had been subjected to corona treatment on the surface facing the retardation film 1 as above, was adjusted so that the slow axis of the film was at an angle of 75° to the transmission axis of PVA, and was then laminated via the adhesive layer 1, thereby obtaining a third liquid crystal retardation film-attached laminate consisting of linear polarizer / adhesive layer 1 / retardation film 1 / adhesive layer 1 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0202] (2) Example 2 A third liquid crystal retardation film-attached laminate consisting of linear polarizer / adhesive layer 1 / retardation film 1 ...alignment film 1 / substrate A was obtained using the same steps as in Example 1, except that in the process of obtaining a second liquid crystal retardation film-attached laminate, adhesive 1 was used instead of adhesive layer 1, and the surface from which substrate A / alignment film 1 had been peeled off from the first liquid crystal retardation film-attached laminate was bonded to the second liquid crystal retardation film. The adhesive 1 was applied to the corona-treated surface of the retardation film 1-attached film using a bar coater so that the thickness after UV curing would be 2 μm. After peeling the substrate A / alignment film 1 from the first liquid crystal retardation film-attached laminate, the adhesive 1 was adhered to the corona-treated surface, and then the adhesive 1 was applied to the corona-treated surface using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) with an integrated light dose of 600 mJ / cm . 2 The film was cured by irradiating it with ultraviolet light from the linear polarizer side under the condition of UV-B. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0203] (3) Example 3 A third liquid crystal retardation film-attached laminate consisting of a linear polarizer / adhesive layer 1 / retardation film 1 / adhesive layer 2 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 2, except that adhesive 2 was used instead of adhesive 1 in Example 2. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0204] (4) Example 4 A third liquid crystal retardation film-attached laminate consisting of a linear polarizer / adhesive layer 1 / retardation film 1 / adhesive layer 3 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 2, except that adhesive 3 was used instead of adhesive 1 in Example 2. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0205] (5) Example 5 A third liquid crystal retardation film-attached laminate consisting of a linear polarizer / adhesive layer 1 / retardation film 1 / adhesive layer 4 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 2, except that adhesive 4 was used instead of adhesive 1 in Example 2. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0206] (6) Example 6 A third liquid crystal retardation film-attached laminate consisting of a linear polarizer / adhesive layer 1 / alignment film 1 / adhesive layer 5 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 2, except that adhesive 5 was used instead of adhesive 1 in Example 2. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0207] (7) Example 7 A third liquid crystal retardation film-attached laminate consisting of linear polarizer / adhesive layer 3 / retardation film 1 / adhesive layer 4 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 5, except that adhesive layer 3 was used instead of adhesive layer 1 used to bond the linear polarizer and the first liquid crystal retardation film in Example 5. The adhesive 3 was applied to the corona-treated retardation film 1-side surface of the film with the retardation film 1 using a bar coater so that the thickness after UV curing would be 2 μm. After bonding to the second protective film (TAC) surface of the linear polarizer, the adhesive 3 was applied to the retardation film 1-side surface of the film with the corona-treated retardation film 1 using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) with an integrated light dose of 600 mJ / cm . 2 The film was cured by irradiating it with ultraviolet light from the linear polarizer side under the condition of UV-B. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0208] (8) Example 8 A third liquid crystal retardation film-attached laminate consisting of linear polarizer / adhesive layer 1 / retardation film 1 / adhesive layer 4 / retardation film 1 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A was obtained in the same manner as in Example 5, except that adhesive layer 1 was used instead of adhesive layer 1 used to bond the linear polarizer and the first liquid crystal retardation film in Example 5. The adhesive 1 was applied to the corona-treated retardation film 1-side surface of the film with the retardation film 1 using a bar coater so that the thickness after UV curing would be 2 μm. After bonding to the second protective film (TAC) surface of the linear polarizer, the adhesive 1 was applied to the retardation film 1-side surface of the film with the corona-treated retardation film 1 using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) with an integrated light dose of 600 mJ / cm . 2 The film was cured by irradiating it with ultraviolet light from the linear polarizer side under the condition of UV-B. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0209] (9) Example 9 A third liquid crystal retarder laminate consisting of a linear polarizer / adhesive layer 1 / retardation film 3 / adhesive 4 / retardation film 4 / pressure-sensitive adhesive layer 1 / retardation film 4 / alignment film 2 / substrate B was obtained in the same manner as in Example 8, except that a film with retardation film 3 was used instead of a film with retardation film 1 as the first liquid crystal retarder film of Example 8, and a film with retardation film 4 was used instead of a film with retardation film 1 as the second liquid crystal retarder film and the third liquid crystal retarder film. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0210] (10) Comparative Example 1 The first liquid crystal retardation film was formed by laminating the first liquid crystal retardation film-attached laminate to the second protective film (TAC) surface of the linear polarizer obtained above via an adhesive layer 1. The surface of the first liquid crystal retardation film (facing the retardation film 2) was corona-treated under the same conditions as above, with the slow axis of the retardation film 2 adjusted to an angle of 15° relative to the transmission axis of the PVA in the linear polarizer. Substrate A / alignment film 1 was then peeled from the resulting first liquid crystal retardation film-attached laminate, and the peeled surface was corona-treated under the same conditions as above. The third liquid crystal retardation film (facing the retardation film 1) was corona-treated on the surface facing the retardation film 1, with the slow axis adjusted to an angle of 75° relative to the absorption axis of the PVA. This resulted in a third liquid crystal retardation film-attached laminate consisting of linear polarizer / adhesive layer 1 / retardation film 2 / adhesive layer 1 / retardation film 1 / alignment film 1 / substrate A. In the obtained laminate, the angle formed between the liquid crystal molecular alignment direction of the first liquid crystal retardation film and the liquid crystal molecular alignment direction of the second liquid crystal retardation film was 0°.

[0211] Table 3 shows the configuration of each circular polarizer in the above examples and comparative examples.

[0212] [Table 3]

[0213] 7. Evaluation (1) Fabrication of organic EL display devices Substrate A or substrate B was peeled off from the laminate with the third liquid crystal retardation film obtained in Examples 1 to 9 and Comparative Example 1, and the surface from which the substrate A or B was peeled off was subjected to a corona treatment once at an output of 0.3 kW and a treatment speed of 3 m / min using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) Next, pressure-sensitive adhesive layer 2 was attached to the corona-treated surface, and the surface of pressure-sensitive adhesive layer 2 was further attached to an organic EL display element to produce an organic EL display device.

[0214] (2) Cloudy unevenness The organic EL display device fabricated as described above was set to black display and placed on a flat table with the display surface facing up. The angle of incidence of the fluorescent light source was set to 45° and the observation angle was set to 90°, with the table at 0°. The appearance was observed at these angles. The observation results were evaluated based on the following criteria. The results are shown in Table 4. A: It showed a good appearance with a tight black display. B: There was a slight whitish tint to the black display. C: Compared to A, it displayed a clearly whitish black color.

[0215] (3) Interference unevenness The organic EL display device fabricated as described above was set to black display and placed on a flat table with the display surface facing up. The angle of incidence of the fluorescent light source was set to 45 degrees and the observation angle was set to 135 degrees, with the table at 0°. The appearance was observed at these angles. The observation results were evaluated based on the following criteria. The results are shown in Table 4. A: No unevenness was visible. B: Slight coloring (interference unevenness) was observed in the black display. C: Coloring (interference unevenness) was observed in the black display.

[0216] (4) Reflectance measurement The organic EL display device fabricated above was set to black display, and the reflectance was measured using a spectrophotometer (CM2600d, Konica Minolta, Inc.). The measurement was performed in SCI mode using a mask with an opening diameter of 8.0 mm when light entered the integrating sphere from the evaluation sample. The reflectance of the center of the measurement sample was measured. The observation results were evaluated based on the following criteria. The results are shown in Table 4. A: Less than 5.00% B: 5.00% or more and less than 5.05% C: 5.05% or more

[0217] (5) Observation of reflected color The organic EL display device fabricated above was set to black display and placed on a flat table with the display surface facing up. The incident angle of the fluorescent light source was set to 45° and the observation angle was set to 90°, with the table at 0°. The color of the image viewed at these angles was observed. The observation results were evaluated based on the following criteria. The results are shown in Table 4. A: No color change was observed on the black display. B: A slight color change was noticed in the appearance of the black display. C: The black display looked more colorful.

[0218] [Table 4]

Claims

1. An optically anisotropic laminate comprising a first liquid crystal retardation film in which a polymerizable liquid crystal compound is aligned, a pressure-sensitive adhesive layer 1, and a second liquid crystal retardation film in which a polymerizable liquid crystal compound is aligned, arranged adjacent to each other in this order, an angle formed by a liquid crystal molecular alignment direction of a first liquid crystal retardation film surface in contact with the adhesive layer 1 and a liquid crystal molecular alignment direction of a second liquid crystal retardation film surface in contact with the adhesive layer 1 is 0±10°; The optically anisotropic laminate comprises a first liquid crystal retardation film and a second liquid crystal retardation film each having a thickness of 0.1 to 3 μm.

2. 2. The optically anisotropic laminate according to claim 1, wherein at least one of the first liquid crystal retardation film and the second liquid crystal retardation film is aligned by a photoalignment film.

3. 2. The optically anisotropic laminate according to claim 1, wherein the adhesive layer 1 is an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound.

4. 2. The optically anisotropic laminate according to claim 1, wherein the adhesive layer 1 has a thickness of 0.1 to 3 μm.

5. 2. The optically anisotropic laminate according to claim 1, wherein the adhesive layer 1 has an in-plane average refractive index of 1.50 to 1.65 at a wavelength of 589 nm.

6. 2. The optically anisotropic laminate according to claim 1, further comprising a third liquid crystal retardation film on the surface of the second liquid crystal retardation film opposite to the adhesive layer 1 via an adhesive layer 2.

7. 7. The optically anisotropic laminate according to claim 6, wherein the adhesive layer 2 is a pressure-sensitive adhesive layer.

8. A circularly polarizing plate comprising a polarizing plate on the surface of the first liquid crystal retardation film of the optically anisotropic laminate according to claim 1 opposite to the adhesive layer 1 via an adhesive layer 3 .

9. 9. The circularly polarizing plate according to claim 8, wherein the adhesive layer 3 is an ultraviolet-curable adhesive layer containing an epoxy compound or a (meth)acrylic compound.

10. 9. The circularly polarizing plate according to claim 8, wherein the adhesive layer has a thickness of 0.1 to 3 μm.

11. 9. The circularly polarizing plate according to claim 8, wherein the adhesive layer 3 has an in-plane average refractive index at a wavelength of 589 nm of 1.45 to 1.

60.

12. 9. The circularly polarizing plate according to claim 8, further comprising a protective film on the pressure-sensitive adhesive layer 3 side of the polarizing plate, the protective film having an in-plane refractive index of 1.45 to 1.

55.

13. 9. The circularly polarizing plate according to claim 8, wherein the angle between the transmission axis of the polarizing plate and the slow axis of the first liquid crystal retardation film is 15±5°.

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