Manufacturing method of alignment liquid crystal film

Abstract

This invention provides a method for manufacturing an aligned liquid crystal film that exhibits minimal changes in optical properties even after prolonged exposure to high temperatures. The method involves bonding the aligned liquid crystal layer and an optical layer in a roll-to-roll manner using an active energy line curing adhesive. The method includes a bonding step in which the aligned liquid crystal layer and the optical layer are bonded in a roll-to-roll manner using an active energy line curing adhesive. The curing shrinkage rate of the adhesive is 11% or less.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an aligned liquid crystal film having an aligned liquid crystal layer having an aligned liquid crystal compound aligned therewith. Prior Technology

[0002] As an optical film (optical anisotropic element) with functions such as optical compensation for liquid crystal displays and anti-reflection of external light in organic EL displays, liquid crystal films (aligned liquid crystal films) with an aligned liquid crystal layer in which liquid crystal compounds are aligned in a specific direction have been used. Compared with polymer-extended films, aligned liquid crystal films have a larger birefringence Δn, which is beneficial for the thinning and weight reduction of image display devices (more specifically, liquid crystal displays, organic EL displays, etc.). In image display devices, the aligned liquid crystal film is laminated to an organic EL panel or liquid crystal display panel as a multilayer formed by an adhesive or bonding agent and polarizing elements in a single volume (see, for example, Patent Document 1).

[0003] Liquid crystal compounds can be aligned in a specific direction by shear forces when coated onto a substrate or by the alignment confinement forces of alignment films. By aligning liquid crystal compounds, various aligned liquid crystal films with optical anisotropy can be obtained. For example, a horizontally aligned liquid crystal layer in which nematic liquid crystal molecules with positive refractive index anisotropy are aligned parallel to each other on a substrate surface can be used as a positive A-plate with refractive index anisotropy of nx > ny = nz.

[0004] When using thermotropic liquid crystals, a solution containing a liquid crystal compound (liquid crystal composition) is coated onto a substrate, and then heated to align the liquid crystal compound in the composition into a liquid crystal state. When the liquid crystal composition contains a photopolymerizable liquid crystal compound (liquid crystal monomer), after aligning the liquid crystal compound, the liquid crystal composition is hardened by light irradiation, thereby fixing the alignment state. [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2015-7700 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] As image display devices increasingly demand greater durability, the optical components that make up the image display device are required to exhibit minimal changes in optical characteristics (more specifically, delay, etc.) even when exposed to high temperatures for extended periods.

[0008] On the other hand, the optical properties of the alignment liquid crystal film can change under high-temperature conditions due to the influence of layers adjacent to the alignment liquid crystal layer. For example, when the alignment liquid crystal layer is bonded to an optical layer (more specifically, a polarizing element, a transparent film, or other alignment liquid crystal layers) via an adhesive layer, there is almost no delay change under high-temperature conditions. In contrast, when the alignment liquid crystal layer and the optical layer are bonded to each other using an active energy line curing adhesive, there is a tendency for the delay to increase under high-temperature conditions.

[0009] Furthermore, the researchers of the present invention have determined that the aforementioned trend of delayed increase under high temperature conditions becomes particularly significant when the alignment liquid crystal layer and the optical layer are bonded together in a roll-to-roll manner using an active energy line curing adhesive.

[0010] In view of this problem, the object of the present invention is to provide a method for manufacturing an alignment liquid crystal film that can produce an alignment liquid crystal film with minimal changes in optical properties even when exposed to high temperature environments for a long time, wherein the alignment liquid crystal layer and the optical layer are bonded together in a roll-to-roll manner using an active energy line curing adhesive. [Technical means to solve the problem]

[0011] The method for manufacturing the aligned liquid crystal film of the present invention comprises a method for manufacturing an aligned liquid crystal film having an aligned liquid crystal layer having an aligned liquid crystal compound aligned therewith, and includes a bonding step, namely, bonding the aligned liquid crystal layer and the optical layer in a roll-to-roll manner using an active energy line curing adhesive. The curing shrinkage rate of the aforementioned adhesive is 11% or less.

[0012] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the bonding step includes an irradiation step, which involves irradiating an active energy line onto a laminate formed by laminating the alignment liquid crystal layer and the optical layer with the adhesive before curing, while the laminate is under tension. For example, in the irradiation step, the active energy line is irradiated onto the laminate while it is under tension of 70 N / 1000 mm width to 550 N / 1000 mm width along the transport direction of the laminate.

[0013] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the bonding step includes a coating step, which involves coating at least one surface of the alignment liquid crystal layer and the optical layer with the adhesive before curing. In the coating step, for example, the adhesive at a temperature between 0°C and 45°C is coated onto the surface.

[0014] In one embodiment of the method for manufacturing the aligned liquid crystal film of the present invention, the bonding step includes an irradiation step, which involves irradiating an active energy line onto a laminate formed by laminating the aligned liquid crystal layer and the optical layer with the adhesive before curing, while the laminate is under tension. In the irradiation step, for example, the active energy line is irradiated onto the laminate under conditions of a cumulative light intensity of 450 mJ / cm² to 1200 mJ / cm².

[0015] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the adhesive before curing comprises an oligomer with a weight average molecular weight of 1000 or more. The content ratio of the oligomer with a weight average molecular weight of 1000 or more to the total amount of the adhesive before curing is, for example, 9.0% by weight or more and 20.0% by weight or less.

[0016] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the thickness of the layer containing the adhesive after the above-mentioned irradiation step is 0.1 μm or more and 3.0 μm or less.

[0017] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the liquid crystal compound is horizontally aligned in the alignment liquid crystal layer.

[0018] In one embodiment of the method for manufacturing the alignment liquid crystal film of the present invention, the birefringence Δn of the alignment liquid crystal layer after the above-mentioned bonding step is 0.03 or more.

[0019] In one embodiment of the method for manufacturing the aligned liquid crystal film of the present invention, the optical layer is a polarizing element, a transparent film, or other aligned liquid crystal layer. [Effects of the Invention]

[0020] The method for manufacturing an alignment liquid crystal film according to the present invention includes a bonding step of bonding the alignment liquid crystal layer and the optical layer in a roll-to-roll manner using an active energy line curing adhesive, and is able to manufacture an alignment liquid crystal film with minimal changes in optical properties even when exposed to high temperature environments for extended periods. Simple Explanation of the Diagram

[0021] Figure 1 is an explanatory diagram illustrating one example of the manufacturing method of the alignment liquid crystal film of the present invention. Figure 2 is a cross-sectional view of an example of an aligned liquid crystal film formed by laminating an aligned liquid crystal layer and an optical layer with an adhesive. Figures 3A, B, C, and D are cross-sectional views showing one example of the manufacturing method of the alignment liquid crystal film shown in Figure 2, divided into steps. Figure 4 is a cross-sectional view of an example of an aligned liquid crystal film formed by laminating an aligned liquid crystal layer and an optical layer with an adhesive. Figure 5 is a cross-sectional view showing an example of an aligned liquid crystal film having an adhesive layer. Figure 6 is a cross-sectional view of an example of an aligned liquid crystal film formed by laminating an aligned liquid crystal layer and an optical layer with an adhesive. Figure 7 is a cross-sectional view showing an example of the layer configuration of an image display device. Implementation

[0022] The preferred embodiments of the present invention will now be described. First, the terminology used in this specification will be explained. The thickness of the alignment liquid crystal layer, the thickness of the optical layer, and the thickness of the layer containing the adhesive after irradiation (curing) by the active energy line (hereinafter sometimes referred to simply as "adhesive layer") are obtained by observing a cross-section of the layer cut along the thickness direction using a transmission electron microscope (TEM), and by randomly selecting 10 measurement locations from the cross-sectional image and measuring the thickness at the selected 10 measurement locations to obtain the arithmetic mean of the 10 measured values.

[0023] The adhesive reaction rate (unit: %) is calculated using the formula {100 × (mass of all monomers in the adhesive used to form the adhesive layer - mass of residual monomers in the adhesive layer) / mass of all monomers in the adhesive used to form the adhesive layer}. The mass of residual monomers in the adhesive layer is determined by LC / MS (liquid chromatography-mass spectrometry). Unless otherwise specified in this specification, the mass of residual monomers in the adhesive layer is the value measured under the following conditions.

[0024] (Determination conditions for the mass of residual monomers in the adsorption layer) Apparatus: High-performance liquid chromatography-mass spectrometry (UltiMate3000 / TSQ QUANTUM ACCESS MAX manufactured by Thermo Fisher Scientific) Tube column: (L-column3 C18 manufactured by the Chemical Substance Evaluation and Research Institute) Flow rate: 1.0 mL / min Column temperature: 40℃ Mobile phase: Utilizing the solvent gradient of ammonium acetate aqueous solution / methanol mobile phase

[0025] The curing shrinkage rate (unit: %) of the adhesive is the volume change rate when the coating layer formed by the adhesive coating hardens to form an adhesive layer at an adhesive reaction rate of 99% or higher, calculated using the formula {100 × (volume of coating layer - volume of adhesive layer) / volume of coating layer}. The method for measuring the curing shrinkage rate is the same as or based on the method described in the examples below. Furthermore, detailed information on the method for measuring the curing shrinkage rate is described in Japanese Patent Application Publication No. 2013-104869, which is incorporated herein by reference.

[0026] Hereafter, the term "system" is sometimes used after the compound name to collectively refer to the compound and its derivatives. When "system" is used after the compound name to indicate a polymer, it means that the repeating unit of the polymer originates from the compound or its derivative. Sometimes acrylic acid and methacrylic acid are collectively referred to as "(meth)acrylic acid". Sometimes acrylates and methacrylates are collectively referred to as "(meth)acrylates". Sometimes acrylonitrile and methacrylic acid are collectively referred to as "(meth)acrylic acid".

[0027] <Manufacturing Method of Alignment Liquid Crystal Film> The method for manufacturing an aligned liquid crystal film according to this embodiment is a method for manufacturing an aligned liquid crystal film comprising an aligned liquid crystal layer in which a liquid crystal compound is aligned. It includes a bonding step, namely, bonding the aligned liquid crystal layer and an optical layer in a roll-to-roll manner using an active energy line curing adhesive. The curing shrinkage rate of the adhesive used in the bonding step is preferably 11% or less.

[0028] According to the method for manufacturing an alignment liquid crystal film of this embodiment, it includes a bonding step of bonding the alignment liquid crystal layer and the optical layer in a roll-to-roll manner using an active energy line curing adhesive, and it is possible to manufacture an alignment liquid crystal film with minimal changes in optical properties even when exposed to high-temperature environments for extended periods. The reason for this is presumably as follows.

[0029] Generally, when manufacturing film products from film materials using a roll-to-roll method, the film material is processed under tension along the transport direction in order to transport it. Therefore, film products manufactured using this method tend to exhibit anisotropic shrinkage stress between the length direction (the transport direction during manufacturing) and the width direction, and are prone to residual stress. Consequently, film products manufactured using this method tend to have optical properties (such as retardation) that easily change under high-temperature conditions. As mentioned above, this tendency is particularly pronounced when the alignment liquid crystal layer and the optical layer are bonded using an active energy line curing adhesive in a roll-to-roll manner.

[0030] In contrast, in this embodiment, an active energy line curing adhesive with a relatively small curing shrinkage rate is used as the adhesive when bonding the alignment liquid crystal layer and the optical layer in a roll-to-roll manner. Therefore, the generation of residual stress caused by the curing shrinkage of the adhesive is suppressed. As a result, it is possible to manufacture an alignment liquid crystal film with minimal changes in optical properties even when exposed to high temperatures for extended periods (hereinafter sometimes referred to as "excellent heat durability").

[0031] In this embodiment, to manufacture an alignment liquid crystal film with superior heat resistance, it is preferable to use an adhesive with a curing shrinkage rate of 10% or less, more preferably an adhesive with a curing shrinkage rate of 9% or less. The lower limit of the curing shrinkage rate of the adhesive is not particularly limited and can also be 0%. In this embodiment, to reduce manufacturing costs, the curing shrinkage rate of the adhesive is preferably 1% or more, more preferably 3% or more, and even more preferably 5% or more. The curing shrinkage rate of the adhesive can be adjusted, for example, by changing the formulation of the adhesive.

[0032] In this embodiment, in order to manufacture an alignment liquid crystal film with better heat resistance while reducing manufacturing costs, the curing shrinkage rate of the adhesive is preferably 1% to 10%, more preferably 1% to 9%, further preferably 3% to 9%, and even more preferably 5% to 9%.

[0033] In this embodiment, the bonding step includes, for example, a coating step and an irradiation step. In the coating step, an adhesive for curing is applied to at least one surface of the alignment liquid crystal layer and the optical layer. In the irradiation step, an active energy line is irradiated onto the laminate formed by stacking the alignment liquid crystal layer and the optical layer with the adhesive for curing while the laminate is under tension.

[0034] The following is a detailed description of this embodiment with reference to the drawings. Furthermore, for ease of understanding, Figures 1 to 7 are shown in a primarily schematic manner. For ease of drawing creation, the size, number, and shape of each component shown may sometimes differ from the actual components. Also, for ease of explanation, sometimes in the drawings described later, the same symbols are used to mark components identical to those described previously, and their descriptions are omitted.

[0035] Figure 1 is an explanatory diagram illustrating one example of the manufacturing method of the alignment liquid crystal film according to this embodiment. As shown in Figure 1, an adhesive is applied to the surface of the film 10 containing the alignment liquid crystal layer (more specifically, the surface of the alignment liquid crystal layer in the film 10 containing the alignment liquid crystal layer) being transported in a roll-to-roll manner by a coating apparatus 11 to form a coating layer 12 (coating step). Furthermore, in Figure 1, a die-dip coating machine is used as the coating apparatus 11, but in this invention, the coating apparatus is not limited, and a gravure coating machine, a reverse coating machine, a bar coating machine, or other coating apparatus can be used depending on the viscosity of the adhesive.

[0036] Subsequently, the film 13 containing the optical layer, which is guided by the guide roller 14 and transported between the first bonding roller 15 and the second bonding roller 16, and the film 10 containing the alignment liquid crystal layer are laminated through the coating layer 12 in the manner described above, to form a laminate 17. At this time, the laminate 17 is formed in a state where the optical layer in the film 13 containing the optical layer is in contact with the coating layer 12.

[0037] Subsequently, the laminate 17 is irradiated with active energy lines (more specifically, ultraviolet light, electron beam, etc.) using the active energy line irradiation device 18 (irradiation step). During the irradiation step, the adhesive in the coating layer 12 hardens, thereby forming an adhesive layer 19, and an aligned liquid crystal film 100 is obtained by bonding the film 10 containing the aligned liquid crystal layer and the film 13 containing the optical layer through the adhesive layer 19. Examples of light sources for the active energy lines include: low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, LEDs, black light lamps, chemical lamps, etc. The illuminance of the active energy line light source is, for example, 100 mW / cm² to 1000 mW / cm², preferably 400 mW / cm² to 800 mW / cm². The active energy line can irradiate the side of the film 10 containing the alignment liquid crystal layer, the side of the film 13 containing the optical layer, or both sides of the laminate 17, according to the transmittance of the active energy line of the film 10 containing the alignment liquid crystal layer and the film 13 containing the optical layer.

[0038] To manufacture an alignment liquid crystal film with superior heat resistance, the thickness of the adhesive layer 19 is preferably 3.0 μm or less, and more preferably 2.8 μm or less. Furthermore, to manufacture an alignment liquid crystal film with excellent adhesion reliability, the thickness of the adhesive layer 19 is preferably 0.1 μm or more, and more preferably 0.5 μm or more. To manufacture an alignment liquid crystal film with superior heat resistance while ensuring adhesion reliability, the thickness of the adhesive layer 19 is preferably 0.1 μm or more and 3.0 μm or less, and more preferably 0.5 μm or more and 2.8 μm or less. The thickness of the adhesive layer 19 can be adjusted by changing the thickness of the coating layer 12.

[0039] In the bonding step described with reference to FIG1, tension is applied to the film 10 containing the alignment liquid crystal layer, the film 13 containing the optical layer, and the laminate 17, for example, by means of an adjusting roller (not shown). The direction of tension is the transport direction for the film 10 containing the alignment liquid crystal layer, the film 13 containing the optical layer, and the laminate 17.

[0040] To manufacture an alignment liquid crystal film with superior heat resistance, it is preferable to irradiate the laminate 17 with active energy lines while applying a tension of 70 N / 1000 mm width to 550 N / 1000 mm width. Furthermore, to manufacture an alignment liquid crystal film with superior heat resistance while stably transporting the laminate 17, it is preferable to irradiate the laminate 17 with active energy lines while applying a tension of 77 N / 1000 mm width to 550 N / 1000 mm width.

[0041] In order to manufacture an alignment liquid crystal film with better heat resistance, it is preferable to irradiate the stack 17 with a cumulative light intensity of 450 mJ / cm² to 1200 mJ / cm², more preferably with a cumulative light intensity of 450 mJ / cm² to 1100 mJ / cm², even more preferably with a cumulative light intensity of 450 mJ / cm² to 800 mJ / cm², and even more preferably with a cumulative light intensity of 450 mJ / cm² to 600 mJ / cm².

[0042] In order to manufacture an alignment liquid crystal film with better heat resistance, the temperature of the adhesive to be coated in the coating step is preferably above 0°C and below 45°C, more preferably above 0°C and below 25°C, and even more preferably above 0°C and below 10°C.

[0043] In order to stably transport the film 10 containing the alignment liquid crystal layer, the film 13 containing the optical layer, and the laminate 17, the transport speed is preferably more than 1 m / min and less than 100 m / min, and more preferably more than 5 m / min and less than 50 m / min.

[0044] The time from the coating step, when the adhesive is applied to the film 10 containing the alignment liquid crystal layer, to the irradiation step, when the active energy line is irradiated onto the laminate 17, is, for example, 0 seconds to 300 seconds.

[0045] In order to manufacture an alignment liquid crystal film with better heat resistance while reducing manufacturing costs, it is preferable to satisfy the following condition 1, more preferably to satisfy the following condition 2, further preferably to satisfy the following condition 3, further preferably to satisfy the following condition 4, and most preferably to satisfy the following condition 5. Condition 1: The curing shrinkage rate of the adhesive is more than 1% and less than 9%, and during the irradiation step, the laminate 17 is irradiated with active energy lines while being subjected to a tension of more than 70 N / 1000 mm width and less than 550 N / 1000 mm width. Condition 2: Condition 1 above must be met, and the temperature of the adhesive to be coated during the coating step must be above 0°C and below 45°C. Condition 3: Condition 2 above is met, and during the irradiation step, the laminate 17 is irradiated with active energy lines at a cumulative light intensity of 450 mJ / cm² to 1200 mJ / cm². Condition 4: Condition 1 above must be met, and the temperature of the adhesive to be coated during the coating step must be between 0°C and 10°C. Condition 5: Condition 4 above is met, and during the irradiation step, the laminate 17 is irradiated with active energy lines at a cumulative light intensity of 450 mJ / cm² to 1200 mJ / cm².

[0046] The above description, with reference to FIG1, illustrates an example of a method for manufacturing an alignment liquid crystal film according to this embodiment, but the present invention is not limited to the above example. For example, in the above example, an adhesive is coated on the alignment liquid crystal layer, but in the present invention, an adhesive may be coated on the optical layer, or an adhesive may be coated on both the alignment liquid crystal layer and the optical layer.

[0047] Next, an example of the configuration of the alignment liquid crystal film obtained by the manufacturing method of this embodiment will be described.

[0048] Figure 2 is a cross-sectional view showing an example of an alignment liquid crystal film obtained by the manufacturing method of this embodiment. The alignment liquid crystal film 101 shown in Figure 2 includes: a support substrate 20, an alignment liquid crystal layer 21 deposited on the support substrate 20, and an optical layer 22 deposited on the alignment liquid crystal layer 21 via an adhesive layer 19.

[0049] Referring to Figures 1 and 3A-D, an example of a method for manufacturing the alignment liquid crystal film 101 shown in Figure 2 will be described. Figures 3A-D are cross-sectional views showing an example of a method for manufacturing the alignment liquid crystal film 101 shown in Figure 2, divided into steps.

[0050] First, a film 10 containing an alignment liquid crystal layer 21 is prepared on a support substrate 20 (Fig. 3A). The film 10 containing the alignment liquid crystal layer is obtained, for example, by coating a liquid crystal composition containing a liquid crystal compound onto the support substrate 20, aligning the liquid crystal compound in a specific direction, and then fixing the alignment state.

[0051] Subsequently, an adhesive is applied to the surface of the aligned liquid crystal layer 21 using the coating apparatus 11 (see Figure 1) to form a coating layer 12 (Figure 3B).

[0052] Subsequently, between the first bonding roller 15 and the second bonding roller 16 (see FIG1), a film 10 containing an alignment liquid crystal layer and a film 13 containing an optical layer having a support substrate 23 and an optical layer 22 are deposited via the coating layer 12 to form a laminate 17 (FIG. 3C). At this time, the laminate 17 is formed with the optical layer 22 in contact with the coating layer 12.

[0053] Next, the laminate 17 is irradiated with active energy lines using an active energy line irradiation device 18 (see Figure 1), causing the adhesive in the coating layer 12 to harden and forming an adhesive layer 19. Then, the support substrate 23 is peeled off from the optical layer 22. Through the above steps, the alignment liquid crystal film 101 shown in Figure 3D can be obtained. Furthermore, the support substrate 23 can be used directly as an alignment liquid crystal film without peeling it off, while the support substrate 23 is attached to the optical layer 22.

[0054] To manufacture an alignment liquid crystal film with superior heat resistance, the absolute value of the difference between the retardation of the alignment liquid crystal layer 21 in Figure 3A and the retardation of the alignment liquid crystal layer 21 in Figure 3D is preferably 3.2 nm or less. There is no particular limitation on the lower limit of the absolute value of the above difference, which can be 0 nm, but from the viewpoint of reducing manufacturing costs, the absolute value of the above difference is preferably 1.5 nm or more. The absolute value of the above difference can be adjusted, for example, by changing at least one of the following: the curing shrinkage rate of the adhesive, the temperature of the adhesive to be coated in the coating step, the tension applied to the laminate 17 in the irradiation step, and the cumulative light intensity of the active energy lines irradiating the laminate 17 in the irradiation step.

[0055] The alignment liquid crystal film 101 can be used directly as an optical component. In this case, the support substrate 20 constitutes a part of the alignment liquid crystal film 101. Alternatively, as shown in FIG. 4, the support substrate 20 can be peeled off from the alignment liquid crystal layer 21 using the alignment liquid crystal film 102. As shown in FIG. 5, an appropriate adhesive layer 30 can be deposited on the surface of the alignment liquid crystal layer 21 exposed by peeling off the support substrate 20 using the alignment liquid crystal film 103, or as shown in FIG. 6, an optical layer 41 can be deposited via an adhesive layer 40 using the alignment liquid crystal film 104.

[0056] There are no particular limitations on the adhesive constituting the adhesive layer 30. Adhesives based on polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluoropolymers, and rubber polymers can be appropriately selected. Particularly preferred are acrylic adhesives or rubber adhesives that exhibit excellent transparency, moderate wetting, coagulation, and adhesion, as well as excellent weather resistance or heat resistance. The thickness of the adhesive layer 30 can be appropriately set according to the type of substrate being adhered to, for example, from 5 μm to 500 μm.

[0057] The adhesive layer 30 is deposited on the alignment liquid crystal layer 21, for example, by attaching a pre-formed sheet adhesive to the surface of the alignment liquid crystal layer 21. Alternatively, after coating the alignment liquid crystal layer 21 with an adhesive composition, solvent drying, crosslinking, photocuring, etc., can be performed to form the adhesive layer 30. To improve the adhesion (holding force) between the alignment liquid crystal layer 21 and the adhesive layer 30, surface treatments such as corona treatment and plasma treatment can be performed on the surface of the alignment liquid crystal layer 21, or an easy-to-adhere layer can be formed before depositing the adhesive layer 30.

[0058] As shown in Figure 5, it is preferable to temporarily attach a release liner 31 to the surface of the adhesive layer 30. The release liner 31 protects the surface of the adhesive layer 30, for example, before the adhesive-coated alignment liquid crystal film 103 is bonded to the image display unit 50 (see Figure 7). As a constituent material of the release liner 31, a plastic film formed of acrylic, polyolefin, cyclic polyolefin, polyester, etc., can be suitably used. The thickness of the release liner 31 is, for example, 5 μm or more and 200 μm or less. It is preferable to perform a release treatment on the surface of the release liner 31. Examples of release agents used for the release treatment include silicone-based materials, fluorine-based materials, long-chain alkyl-based materials, and fatty acid amide-based materials.

[0059] When manufacturing the alignment liquid crystal film 104 shown in Figure 6, the alignment liquid crystal layer 21 and the optical layer 22 can be bonded together with an adhesive, and then the alignment liquid crystal layer 21 and the optical layer 41 can be bonded together with an adhesive. Alternatively, the alignment liquid crystal layer 21 and the optical layer 41 can be bonded together with an adhesive, and then the alignment liquid crystal layer 21 and the optical layer 22 can be bonded together with an adhesive. Furthermore, the alignment liquid crystal layer 21 and the optical layer 22, as well as the alignment liquid crystal layer 21 and the optical layer 41, can be bonded together simultaneously with an adhesive. An adhesive layer (not shown) can be further deposited on the optical layer 22 or the optical layer 41, and a release liner (not shown) can be temporarily adhered to the surface of the adhesive layer.

[0060] Next, the materials used in the manufacturing method of the alignment liquid crystal film of this embodiment will be described.

[0061] [Liquid Crystalline Composition] Examples of liquid crystal compounds included in liquid crystal compositions include rod-shaped liquid crystal compounds and disc-shaped liquid crystal compounds. Rod-shaped liquid crystal compounds are preferred because they are easily horizontally oriented by the alignment restraint force of the supporting substrate 20. Rod-shaped liquid crystal compounds can be polymers. For example, rod-shaped liquid crystal compounds can be liquid crystal polymers (more specifically, main-chain liquid crystal polymers, side-chain liquid crystal polymers, etc.), or polymers of polymerizable liquid crystal compounds. If the liquid crystal compound (monomer) exhibits liquid crystal properties before polymerization, it may not exhibit liquid crystal properties after polymerization.

[0062] The liquid crystal compound is preferably a thermotropic liquid crystal that exhibits liquid crystal properties upon heating. Thermotropic liquid crystals undergo phase transfer between a crystalline phase, a liquid crystal phase, and an isotropic phase with temperature changes. The liquid crystal compound contained in the liquid crystal composition can be any of nematic liquid crystals, smectic liquid crystals, and cholesteric liquid crystals. A chiral agent can also be added to a nematic liquid crystal to give it cholesteric orientation properties.

[0063] Examples of rod-shaped liquid crystal compounds exhibiting thermotropic properties include: methylimine compounds, oxoazo compounds, cyanobiphenyl compounds, cyanophenyl ester compounds, benzoate compounds, cyclohexanecarboxylic acid phenyl ester compounds, cyanophenylcyclohexane compounds, cyano-substituted phenylpyrimidine compounds, alkoxy-substituted phenylpyrimidine compounds, phenyldialkyl compounds, diphenylacetylene compounds, and alkenylcyclohexylbenzonitrile compounds.

[0064] Examples of polymerizable liquid crystal compounds include: polymerizable liquid crystal compounds in which the alignment state of rod-shaped liquid crystal compounds can be fixed using a polymer binder; and polymerizable liquid crystal compounds having polymerizable functional groups in which the alignment state of liquid crystal compounds can be fixed by polymerization. Among these, photopolymerizable liquid crystal compounds having photopolymerizable functional groups are preferred.

[0065] The photopolymerizable liquid crystal compound (liquid crystal monomer) has a liquid crystal primitive and at least one photopolymerizable functional group in one molecule. The temperature at which the liquid crystal monomer exhibits liquid crystal properties (liquid crystal phase transition temperature) is preferably 40°C to 200°C, more preferably 50°C to 150°C, and even more preferably 55°C to 100°C.

[0066] Examples of liquid crystal monomers that form liquid crystal primitives include: biphenyl, phenylbenzoate, phenylcyclohexyl, oxazophenyl, azophenyl, phenylpyrimidinyl, diphenylethynyl, diphenylbenzoate, bicyclohexyl, cyclohexylphenyl, and triphenyl, among other cyclic structures. The ends of these cyclic units can also be substituted with cyano, alkyl, alkoxy, or halogen groups.

[0067] Examples of photopolymerizable functional groups include (meth)acrylyl, epoxy, and vinyl ether groups. Among these, (meth)acrylyl is preferred. The liquid crystal monomer preferably has two or more photopolymerizable functional groups per molecule. By using a liquid crystal monomer containing two or more photopolymerizable functional groups, a cross-linking structure is introduced into the photocured liquid crystal layer, thus tending to improve the durability of the aligned liquid crystal film.

[0068] As the liquid crystal monomer, any suitable liquid crystal monomer can be used. For example, International Patent Publication No. 00 / 37585, US Patent No. 5211877, US Patent No. 4388453, International Patent Publication No. 93 / 22397, European Patent No. 0261712, German Patent No. 19504224, German Patent No. 4408171, British Patent No. 2280445, Japanese Patent Application Publication No. 2017-206460, International Patent Publication No. 2014 / 126113, International Patent Publication No. 2016 / 114348, International Patent Publication No. 2014 / 010325, and Japanese Patent Application Publication No. 2015-200877 can be used. Compounds described in Japanese Patent Application Publication No. 2010-31223, International Publication No. 2011 / 050896, Japanese Patent Application Publication No. 2011-207765, Japanese Patent Application Publication No. 2010-31223, Japanese Patent Application Publication No. 2010-270108, International Publication No. 2008 / 119427, Japanese Patent Application Publication No. 2008-107767, Japanese Patent Application Publication No. 2008-273925, International Publication No. 2016 / 125839, and Japanese Patent Application Publication No. 2008-273925 are used as liquid crystal monomers. By selecting the liquid crystal monomer, the birefringence performance and the wavelength dispersion of the delay can also be adjusted.

[0069] In addition to liquid crystal monomers, the liquid crystal composition may also contain compounds (alignment control agents) that control the alignment of liquid crystal monomers in a specific direction. For example, by including a side-chain type liquid crystal polymer in the liquid crystal composition, the liquid crystal compound (monomer) can be vertically aligned. Furthermore, by adding a chiral agent to the liquid crystal composition, the liquid crystal compound can be cholesterol-type aligned.

[0070] The liquid crystal composition may contain a photopolymerization initiator. In cases where liquid crystal monomers are cured by ultraviolet irradiation, to promote photocuring, the liquid crystal composition preferably contains a photoradical polymerization initiator (photoradical generator) that generates free radicals upon light irradiation. Depending on the type of liquid crystal monomer (the type of photopolymerizable functional group), a photocation generator or a photoanion generator may be used. The amount of photopolymerization initiator used is, for example, 0.01 parts by weight to 10 parts by weight relative to 100 parts by weight of the liquid crystal monomer. In addition to the photopolymerization initiator, sensitizers, etc., may also be used.

[0071] Liquid crystal compositions can be prepared by mixing liquid crystal monomers, various alignment control agents and polymerization initiators used as needed, with a solvent. As a solvent, there are no particular limitations as long as it can dissolve the liquid crystal monomers and does not corrode the supporting substrate 20 (or has low corrosivity). Examples include: halogenated hydrocarbon compounds such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and o-dichlorobenzene; phenolic compounds such as phenol and p-chlorophenol; aromatic hydrocarbon compounds such as benzene, toluene, xylene, methoxybenzene, and 1,2-dimethoxybenzene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone. Ketone solvents such as 2-pyrrolidone and N-methyl-2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; alcohol solvents such as butanol, glycerol, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, and 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile solvents such as acetonitrile and butyronitrile; ether solvents such as diethyl ether, dibutyl ether, and tetrahydrofuran; and cellosolve solvents such as ethyl cellosolve and butyl cellosolve. Mixtures of two or more solvents may also be used.

[0072] The concentration of solids in the liquid crystal composition is, for example, 5% by weight or more and 60% by weight or less. The liquid crystal composition may contain additives such as surfactants or leveling agents.

[0073] [Supporting Substrate] As for the support substrates 20 and 23, there are no particular limitations as long as they can be transported in a roll-to-roll manner. From the viewpoint of ease of transport, film substrates (more specifically, resin film substrates, etc.) are preferred. The support substrates 20 and 23 can be made of the same material or of different types of materials. There are no particular limitations on the thickness of the support substrates 20 and 23, for example, 1 μm or more and 500 μm or less. The thicknesses of the support substrates 20 and 23 can be the same or different. The support substrate 20 has a first main surface and a second main surface, and a liquid crystal composition is coated on the first main surface.

[0074] As for the resin material constituting the resin film substrate, there are no particular limitations as long as it is not soluble in the solvent of the liquid crystal composition and has heat resistance when heated to orient the liquid crystal composition. Examples include: polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; cyclic polyolefins such as norcamphene polymers; cellulose polymers such as diacetylcellulose and triacetylcellulose; acrylic polymers; styrene polymers; polycarbonate; polyamide; polyimide, etc.

[0075] The support substrate 20 may have an alignment capability that allows the liquid crystal compound to align in a specific direction. For example, by using an extended film as the support substrate 20, the liquid crystal compound can be horizontally aligned along its extension direction. The extension ratio of the extended film is only required to achieve the alignment capability, for example, 1.1 times to 5 times. The extended film may be a biaxial extended film. Even with a biaxial extended film, as long as a film with different extension ratios in the longitudinal and transverse directions is used, the liquid crystal compound can be aligned along the direction with the larger extension ratio. The extended film may also be a tilted extended film. By using a tilted extended film as the support substrate 20, the liquid crystal compound can be aligned along a direction that is not parallel to either the length or width direction of the support substrate 20.

[0076] The support substrate 20 may have an alignment film on its first main surface. The alignment film can be appropriately selected based on the type of liquid crystal compound or the material of the support substrate 20. As an alignment film used to horizontally align the liquid crystal compound in a specific direction, an alignment film obtained by rubbing a polyimide-based or polyvinyl alcohol-based alignment film can be suitable. Alternatively, a photoalignment film can also be used. Alternatively, an alignment film may not be provided, and the resin film serving as the support substrate 20 may be rubbed.

[0077] The support substrate 20 may have an alignment film for vertically aligning the liquid crystal compound. Examples of alignment agents used to form the vertically aligned alignment film (vertical alignment film) include: lecithin, stearic acid, hexadecyltrimethylammonium bromide, octadecylamine hydrochloride, monocarboxylic acid chromium complex, organosilanes (more specifically, silane coupling agents, siloxane compounds, etc.), perfluorodimethylcyclohexane, tetrafluoroethylene, polytetrafluoroethylene, etc.

[0078] [Alignment Liquid Crystal Layer] When the liquid crystal compound is a thermotropic liquid crystal, a liquid crystal composition is coated on the first main surface of the support substrate 20, and the liquid crystal compound is oriented in a liquid crystal state by heating.

[0079] The method for coating the liquid crystal composition on the support substrate 20 is not particularly limited, and methods such as spin coating, die coating, contact roller coating, gravure coating, reverse coating, spraying, Mayer rod coating, knife roller coating, and air knife coating can be used. A liquid crystal composition layer is formed on the support substrate 20 by removing the solvent after coating the liquid crystal composition. The thickness of the coating layer formed by coating the liquid crystal composition is preferably adjusted to be between 0.1 μm and 20 μm after solvent removal.

[0080] The liquid crystal composition layer formed on the support substrate 20 is heated to make it a liquid crystal phase, thereby orienting the liquid crystal compound to form an aligned liquid crystal layer 21. Specifically, the liquid crystal composition is coated on the support substrate 20, and then heated to above the N (nematic)-I (isotropic liquid phase) transition temperature of the liquid crystal composition to make the liquid crystal composition an isotropic liquid state. Then, it is slowly cooled as needed to make it exhibit a nematic phase. At this time, it is desirable to temporarily maintain the temperature of exhibiting a liquid crystal phase to allow the liquid crystal phase domain to grow into a single domain. Alternatively, the liquid crystal composition can be coated on the support substrate 20, and then the temperature can be maintained in the temperature range of exhibiting a nematic phase for a certain period of time to orient the liquid crystal compound in a specific direction.

[0081] The heating temperature for aligning the liquid crystal compound in a specific direction can be appropriately selected according to the type of liquid crystal composition, for example, between 40°C and 200°C. If the heating temperature is too low, the transfer to the liquid crystal phase tends to be insufficient; if the heating temperature is too high, alignment defects may increase. The heating time can be adjusted to ensure sufficient growth of the liquid crystal phase domain, for example, between 30 seconds and 30 minutes.

[0082] Preferably, after aligning the liquid crystal compound by heating, the liquid crystal is cooled to a temperature below the glass transition temperature. The cooling method is not particularly limited; for example, simply removing it from the heated atmosphere to room temperature is sufficient. Forced cooling such as air cooling or water cooling can also be used.

[0083] Photocuring is achieved by irradiating aligned photopolymerizable liquid crystal compounds with light, allowing the photopolymerizable liquid crystal compounds (liquid crystal monomers) to exhibit liquid crystal regularity. The irradiation light need only be sufficient to polymerize the photopolymerizable liquid crystal compounds; ultraviolet or visible light with wavelengths between 250 nm and 450 nm is typically used. When the liquid crystal composition contains a photopolymerization initiator, light with a wavelength to which the photopolymerization initiator is sensitive can be selected. As the irradiation light source, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, LEDs, black lights, chemical lamps, etc., can be used. To promote the photocuring reaction, irradiation is preferably carried out in an inert gas atmosphere such as nitrogen.

[0084] During the photocuring of the liquid crystal composition, the liquid crystal compound can be aligned in a specific direction by using polarized light in a specific direction. As described above, when the liquid crystal compound is aligned by the alignment restraint force of the support substrate 20, the irradiation light can also be unpolarized light (natural light).

[0085] The intensity of the irradiation light can be adjusted appropriately according to the composition of the liquid crystal composition or the amount of photopolymerization initiator added. The irradiation energy (cumulative light intensity) is, for example, 20 mJ / cm² to 10000 mJ / cm², preferably 50 mJ / cm² to 5000 mJ / cm², and even more preferably 100 mJ / cm² to 800 mJ / cm². To promote the photocuring reaction, light irradiation can be carried out under heating conditions.

[0086] The polymer formed by photocuring liquid crystal monomers under light irradiation is non-liquid crystal and does not undergo phase transition due to temperature changes. Therefore, liquid crystal layers photocured with liquid crystal monomers aligned in a specific direction are generally less prone to changes in molecular alignment. Furthermore, compared to films containing non-liquid crystal materials, aligned liquid crystal films have a much larger birefringence Δn, thus significantly reducing the thickness of optical anisotropic elements with the desired retardation. The thickness of the aligned liquid crystal layer 21 can be set according to the target retardation value, for example, 0.1 μm to 20 μm, preferably 0.2 μm to 10 μm, and even more preferably 0.5 μm to 7 μm.

[0087] The optical properties of the aligned liquid crystal layer 21 are not particularly limited. The in-plane retardation and thickness retardation of the aligned liquid crystal layer 21 can be appropriately set according to the application, etc. In the case where the liquid crystal compound is horizontally aligned in the aligned liquid crystal layer 21, the in-plane retardation of the aligned liquid crystal layer 21 is, for example, 20 nm or more and 1000 nm or less. In the case where the aligned liquid crystal layer 21 is a quarter-wavelength plate, the in-plane retardation is preferably 100 nm or more and 180 nm or less, and more preferably 120 nm or more and 150 nm or less. In the case where the aligned liquid crystal layer 21 is a half-wavelength plate, the in-plane retardation is preferably 200 nm or more and 340 nm or less, and more preferably 240 nm or more and 300 nm or less. In the case where the liquid crystal compound is vertically aligned in the aligned liquid crystal layer 21, the in-plane retardation of the aligned liquid crystal layer 21 is approximately 0 (for example, 5 nm or less, preferably 3 nm or less), and the absolute value of the thickness retardation is, for example, 30 nm or more and 500 nm or less.

[0088] When the liquid crystal compound in the aligned liquid crystal layer 21 is horizontally aligned, in order to reduce the thickness of the optical anisotropic element, it is preferable that the birefringence Δn of the aligned liquid crystal layer 21 after the bonding step is 0.03 or more. Furthermore, when the liquid crystal compound in the aligned liquid crystal layer 21 is horizontally aligned, in order to easily adjust the in-plane retardation of the aligned liquid crystal layer 21, it is preferable that the birefringence Δn of the aligned liquid crystal layer 21 after the bonding step is 0.5 or less. The birefringence Δn of the aligned liquid crystal layer 21 can be adjusted, for example, by changing the type of liquid crystal compound used to form the aligned liquid crystal layer 21.

[0089] [Optical layer] Optical layers 22 and 41 are not particularly limited. For example, optically isotropic or anisotropic optical films commonly used in general applications can be used as optical layers 22 and 41 without limitation. Specific examples of optical layers 22 and 41 include: transparent films (more specifically, retardation films, polarizing element protective films, etc.), functional films (more specifically, polarizing elements, viewing angle widening films, viewing angle limiting (privacy) films, brightness enhancement films, etc.). Optical layers 22 and 41 can be single layers or laminates. Optical layers 22 and 41 can be alignment liquid crystal layers (other alignment liquid crystal layers). Furthermore, optical layer 22 can be a polarizing plate with a transparent protective film laminated to one or both sides of the polarizing element. When a transparent protective film is provided on one side of the polarizing plate, the polarizing element can be laminated to the alignment liquid crystal layer 21, or the transparent protective film can be laminated to the alignment liquid crystal layer 21. Optical layer 22 and optical layer 41 can be made of the same material or of different materials. The thickness of optical layer 22 and optical layer 41 can be adjusted appropriately according to the required optical performance, for example, from 0.1 μm to 1000 μm, preferably from 0.1 μm to 100 μm. The thickness of optical layer 22 and optical layer 41 can be the same or different.

[0090] [Adhesive layer] The adhesives constituting adhesive layers 19 and 40 are not particularly limited as long as they are active energy line curing adhesives with low curing shrinkage (e.g., curing shrinkage of 11% or less) and optically transparent. Examples include epoxy resin adhesives, silicone resin adhesives, acrylic resin adhesives, polyurethane adhesives, polyamide adhesives, and polyether adhesives. Adhesive layers 19 and 40 can be composed of the same type of adhesive or of different types. The preferred range of the thickness of adhesive layer 40 is the same as the preferred range of the thickness of adhesive layer 19 described above. The thicknesses of adhesive layer 19 and adhesive layer 40 can be the same or different.

[0091] Active energy line curing adhesives are adhesives that can undergo free radical polymerization, cationic polymerization, or anionic polymerization by irradiation with active energy lines such as electron beams or ultraviolet light. Among them, based on the ability to cure at low energy, photoradical polymerizing adhesives, photocationic polymerizing adhesives, or hybrid adhesives that combine photocationic and photoradical polymerization are preferred.

[0092] Monomers for photoradical polymerizable adhesives may include compounds having a (meth)acrylic group or compounds having a vinyl group. Among these, compounds having a (meth)acrylic group are preferred. Examples of compounds having a (meth)acrylic group include: C1-20 chain alkyl esters of (meth)acrylate, alicyclic alkyl esters of (meth)acrylate, polycyclic alkyl esters of (meth)acrylate, and other alkyl esters of (meth)acrylate; hydroxyl-containing (meth)acrylates; glycidyl esters of (meth)acrylate, and other epoxy-containing (meth)acrylates. Photoradical polymerizable adhesives may contain nitrogen-containing monomers such as hydroxyethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, (meth)acrylamide, and (meth)acrylamide morpholine. Photoradical polymerizable adhesives may contain multifunctional monomers such as tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecanediethanol diacrylate, cyclic trimethylolpropane formal acrylate, dialkyldiol diacrylate, and polyethylene glycol diacrylate as crosslinking components.

[0093] Compounds having epoxy groups or oxobutyl groups can be listed as curing components in photocationic polymerizable adhesives. There are no particular limitations on the epoxy group content, as long as the compound has at least two epoxy groups within its molecule; various commonly known curable epoxy compounds can be used. Preferred epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring within their molecule (aromatic epoxy compounds), and compounds having at least two epoxy groups within their molecule, with at least one of them formed between two adjacent carbon atoms constituting an alicyclic ring (alicyclic epoxy compounds). Hybrid adhesives can also be prepared by containing free radical polymerizable compounds such as compounds having (meth)acrylic groups in the cationic polymerizable adhesive.

[0094] To obtain an adhesive with a low curing shrinkage rate, it is preferable to adjust the adhesive formulation in a way that reduces the number of bonds formed during curing. To reduce the number of bonds, it is preferable to use monomers with a higher molecular weight for each reactive functional group (e.g., (meth)acrylic acid esters). Examples of monomers with a higher molecular weight for each reactive functional group include alkyl (meth)acrylates (e.g., isostearyl acrylate) having alkyl groups with 10, 12, 14, 16, or 18 carbon atoms, and polyoxyethylene glycol diacrylates having 5, 7, or 9 or more ethyl groups per molecule.

[0095] Furthermore, when the adhesive before curing contains oligomers with a weight average molecular weight of 1000 or more, an adhesive with a lower curing shrinkage rate can be obtained. Examples of oligomers with a weight average molecular weight of 1000 or more (hereinafter sometimes referred to as "specific oligomers") include oligomers formed from monomers having (meth)acrylic groups (acrylic oligomers). Acrylic oligomers may also have cationic polymerizable functional groups (e.g., epoxy groups).

[0096] In order to manufacture an alignment liquid crystal film with better heat resistance while ensuring bonding reliability, the weight average molecular weight of the specific oligomer is preferably 1,000 to 10,000, more preferably 1,000 to 5,000, further preferably 1,000 to 3,000, and even more preferably 1,500 to 3,000.

[0097] In order to manufacture an alignment liquid crystal film with better heat resistance while ensuring bonding reliability, the content ratio of a specific oligomer relative to the total amount of adhesive before curing is preferably 9.0% to 20.0% by weight, more preferably 9.0% to 15.0% by weight, and even more preferably 9.4% to 14.2% by weight.

[0098] The weight-average molecular weight of a particular oligomer can be determined by gel permeation chromatography (GPC). Unless otherwise specified in this specification, the weight-average molecular weight of a particular oligomer is a converted value of standard polystyrene obtained under the following conditions.

[0099] (Conditions for molecular weight determination) GPC measuring device: HLC-8120GPC manufactured by Tosoh Corporation. Sample concentration: 2.0 g / L (tetrahydrofuran solution) Sample injection volume: 20 μL Tube Column: "TSKgel, SuperAWM-H+superAW4000+superAW2500" manufactured by Tosoh Corporation Tube string dimensions: 6.0 mm I.D. × 150 mm each Dissolution solution: Tetrahydrofuran Flow rate: 0.4 mL / min Detector: Differential refractometer (RI) Column temperature (measurement temperature): 40℃

[0100] Photocurable adhesives preferably contain a photopolymerization initiator. The photopolymerization initiator can be appropriately selected according to the type of reaction. For example, it is preferable to use a photoradical polymerization initiator that generates free radicals by light irradiation as the photopolymerization initiator in a photocationic polymerization adhesive. It is preferable to use a photocationic polymerization initiator (photoacid generator) that generates cationic species or Lewis acids by light irradiation as the photopolymerization initiator in a photocationic polymerization adhesive. It is preferable to use both a photocationic polymerization initiator and a photoradical polymerization initiator in a mixed adhesive.

[0101] The content of the photopolymerization initiator relative to 100 parts by weight of the monomer is, for example, 0.1 parts by weight to 10 parts by weight, preferably 0.5 parts by weight to 3 parts by weight. If necessary, a photosensitizer may also be formulated into the photocurable adhesive. The amount of photosensitizer used relative to 100 parts by weight of the monomer is, for example, 0.001 parts by weight to 10 parts by weight, preferably 0.01 parts by weight to 3 parts by weight.

[0102] Adhesives may contain appropriate additives as needed. Examples of additives include: silane coupling agents, titanium coupling agents, and other coupling agents; ethylene oxide adhesive accelerators; ultraviolet absorbers; deterioration inhibitors; dyes; processing aids; ion traps; antioxidants; adhesion promoters; fillers; plasticizers; leveling agents; foaming inhibitors; antistatic agents; heat stabilizers; and hydrolysis stabilizers.

[0103] [use] The alignment liquid crystal film obtained by the manufacturing method of this embodiment can be used, for example, as an optical film for displays for purposes such as improving visibility.

[0104] The alignment liquid crystal film obtained by the manufacturing method of this embodiment can be a circular polarizer on one side of the alignment liquid crystal layer 21, with a polarizer serving as an optical layer 22 bonded to it via an adhesive layer 19. The circular polarizer may also have two or more alignment liquid crystal layers.

[0105] A polarizing plate may consist of only one polarizing element, or, as described above, a transparent protective film may be laminated to one or both sides of the polarizing element. Examples of polarizing elements include: hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, which adsorb dichroic substances such as iodine or dichroic dyes and then undergo uniaxial extension; and polyene alignment films such as dehydrated polyvinyl alcohol products or dehydrochlorinated polyvinyl chloride products.

[0106] Among these, a preferred method for obtaining a polyvinyl alcohol (PVA) polarizing element is to adsorb iodine or dichroic dyes onto a polyvinyl alcohol film, such as a partially formalized polyvinyl alcohol film, and orient it in a specific direction. For example, a PVA polarizing element can be obtained by iodizing and stretching a polyvinyl alcohol film. Alternatively, a PVA resin layer can be formed on a resin substrate, and iodine staining and stretching can be performed in a laminated state.

[0107] In a circular polarizer, at least one aligned liquid crystal layer is preferably horizontally aligned with a liquid crystal compound. The circular polarizer is configured such that the alignment direction of the liquid crystal compound in the horizontally aligned liquid crystal layer is neither parallel nor orthogonal to the absorption axis direction of the polarizing element.

[0108] When the circular polarizer has only one alignment liquid crystal layer, for example, when the alignment liquid crystal layer 21 is a 1 / 4 wavelength plate, the angle between the absorption axis direction of the polarizer (which serves as the optical layer 22) and the alignment direction of the liquid crystal compound (generally the late phase axis direction) is set to 45°. The angle between the absorption axis direction of the polarizer and the alignment direction of the liquid crystal compound can be 35° to 55°, 40° to 50°, or 43° to 47°.

[0109] In a configuration formed by stacking a polarizing plate (optical layer 22) and a quarter-wavelength plate (aligned liquid crystal layer 21) with their optical axes forming an angle of 45°, an alignment liquid crystal layer with vertical alignment of the liquid crystal compound is further provided as an optical layer 41 (see Figure 6). By sequentially stacking the alignment liquid crystal layer 21 (serving as a quarter-wavelength plate) and the optical layer 41 (serving as a positive C-plate) on the polarizing plate, a circular polarizing plate that can block reflected light from external light from an inclined direction can be formed. A vertically aligned liquid crystal layer (positive C-plate) and a horizontally aligned liquid crystal layer (a quarter-wavelength plate serving as a positive A-plate) can be sequentially stacked on the polarizing plate.

[0110] In the case shown in Figure 6, where the aligned liquid crystal film 104 is a circular polarizer on a polarizer serving as optical layer 22, in which aligned liquid crystal layer 21 and aligned liquid crystal layer 41 are sequentially deposited, both aligned liquid crystal layer 21 and optical layer 41 can be horizontally aligned liquid crystal layers. In this case, it is preferable that the aligned liquid crystal layer 21 disposed near optical layer 22 is a 1 / 2 wavelength plate, and the optical layer 41 disposed away from optical layer 22 is a 1 / 4 wavelength plate. In this layer configuration, it is preferable that the angle between the late phase axis direction of the 1 / 2 wavelength plate and the absorption axis direction of the polarizer is 75°±5°, and the angle between the late phase axis direction of the 1 / 4 wavelength plate and the absorption axis direction of the polarizer is 15°±5°. This layer configuration allows the circular polarizer to function as a circular polarizer over a wide wavelength range of visible light, thus reducing the chromatic aberration of reflected light.

[0111] <Image display device> Figure 7 is a cross-sectional view showing an example of the layer configuration of an image display device. An alignment liquid crystal film having an alignment liquid crystal layer 21 (an alignment liquid crystal film obtained by the manufacturing method of this embodiment) is bonded to the surface of the image display unit 50 via an adhesive layer 30. The alignment liquid crystal film may have two or more alignment liquid crystal layers. Examples of image display units 50 include liquid crystal cells or organic EL cells.

[0112] As described above, the heat resistance of the alignment liquid crystal layer 21 of the alignment liquid crystal film obtained by the manufacturing method of this embodiment is improved. Therefore, even when the image display device 200 shown in FIG7 is exposed to a high temperature environment for a long time, the delay change of the alignment liquid crystal layer 21 is small, and thus the change in visibility is small, and the heat resistance is excellent. [Example]

[0113] The present invention will be described in more detail below by providing examples of the fabrication of alignment liquid crystal films, but the present invention is not limited to the following examples.

[0114] <Preparation of Adhesives A-1~A-7> UV-curing adhesives A-1 to A-7 were prepared by mixing the components shown in Table 1 according to the proportions shown in Table 1. Furthermore, in Table 1, all proportions are relative to the total amount of adhesive.

[0115] Furthermore, the meanings of the terms in Table 1 are as follows. HEAA: Hydroxyethyl acrylamide (manufactured by KJ Chemical Company, "HEAA (registered trademark)") ACMO: Acrylamide (manufactured by KJ Chemical Company, "ACMO (registered trademark)") M-5700: Acrylate monomer (Aronix M-5700 manufactured by Dong-A Synthetic Co., Ltd., a registered trademark) P2H-A: Phenoxy diethylene glycol acrylate (Light acrylate (registered trademark) P2H-A, manufactured by Kyoei Chemical Co., Ltd.) FA1DDM: Unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (Plaxel FA1DDM manufactured by Cadena Lu) ISTA: Isostearyl acrylate (ISTA manufactured by Osaka Organic Chemicals Co., Ltd.) LA: Lauryl acrylate (Light acrylate (registered trademark) LA, manufactured by Kyoei Chemical Co., Ltd.) M-220: Acrylate monomer (Aronix M-220 manufactured by Toa Synthetic Co., Ltd., a registered trademark) 1,9ND-A: 1,9-Nonadiol diacrylate (Light acrylate (registered trademark) 1,9ND-A, manufactured by Kyoei Chemical Co., Ltd.) 9EG-A: Polyoxyethylene glycol diacrylate ("Light acrylate (registered trademark) 9EG-A" manufactured by Kyoei Chemical Co., Ltd., with 9 ethyl groups per molecule) 14EG-A: Polyoxyethylene glycol diacrylate (Light acrylate (registered trademark) 14EG-A manufactured by Kyoei Chemical Co., Ltd., with 14 oxyethylated molecules per molecule) TMP-A: Trimethylolpropane triacrylate (Light acrylate (registered trademark) TMP-A, manufactured by Kyoesha Chemical Co., Ltd.) M-930: Acrylate monomer (Aronix M-930 manufactured by Dong-A Synthetic Co., Ltd., a registered trademark) UP-1190: Acrylic oligomer (ARUFON UP-1190 manufactured by Dong-A Synthetic Co., Ltd., weight average molecular weight: 1700) UG-4010: An epoxy-containing acrylic oligomer (manufactured by Dong-A Synthetic Co., Ltd., "ARUFON (registered trademark) UG-4010", weight average molecular weight: 2900) Omnirad 907: Photoradical polymerization initiator (Omnirad 907, manufactured by IGM Resins, a registered trademark) DETX-S: Photoradical polymerization initiator (manufactured by Nippon Kayaku Co., Ltd. as "KAYACURE (registered trademark) DETX-S") CPI-100P: Photocationic polymerization initiator (CPI-100P manufactured by San Apro Corporation).

[0116] Furthermore, the curing shrinkage rate values ​​in Table 1 were measured using a resin curing shrinkage stress measuring device (SENTEC's "EU201") under conditions without applied tension. Specifically, on the measuring platform of the device, each adhesive was coated with a 1.0 μm thickness at 25°C. Each adhesive was irradiated with ultraviolet light using a high-pressure mercury lamp with an illuminance of 10 mW / cm² and a cumulative light intensity of 600 mJ / cm². The curing shrinkage rate of each adhesive was then measured. Moreover, for any adhesive from A-1 to A-7, the adhesive reaction rate after the curing shrinkage rate was measured (the cured adhesive) was 99%.

[0117] [Table 1] The percentage of each component in the adhesive [by weight %] A-1 A-2 A-3 A-4 A-5 A-6 A-7 Free radical polymerization Monofunctional monomer HEAA 9.4 14.4 9.4 9.4 ACMO 28.3 18.9 18.9 14.4 M-5700 9.4 9.4 9.4 P2H-A 42.6 42.6 42.6 FA1DDM 47.2 18.9 9.4 ISTA 26.0 28.2 LA 9.4 14.2 Free radical polymerization Multifunctional monomers M-220 9.4 9.6 9.4 9.4 1,9ND-A 14.2 9.4 14.2 14.2 9EG-A 7.1 14EG-A 9.4 TMP-A 4.7 0.9 M-930 57.8 4.7 acrylic oligomers UP-1190 9.4 11.8 11.8 8.5 UG-4010 14.2 Photoradical polymerization initiator Omnirad 907 2.8 2.8 2.8 1.9 1.9 2.8 2.8 DETX-S 2.8 2.8 2.8 1.9 1.9 2.8 2.8 Photocationic polymerization initiator CPI-100P 1.9 Hardening shrinkage rate [%) 11 9 7 5 15 13 12

[0118] <Construction of L-1 laminate> A photopolymerizable liquid crystal compound exhibiting a nematic liquid crystal phase (Paliocolor LC242, manufactured by BASF) was dissolved in cyclopentanone to prepare a solution with a solid content of 30% by weight. A surfactant (BYK-360, manufactured by Big Chemie Japan) and a photopolymerization initiator (Omnirad 907, manufactured by IGM Resins) were added to this solution to prepare a liquid crystal composition. The amounts of surfactant and photopolymerization initiator added relative to 100 parts by weight of the photopolymerizable liquid crystal compound were set to 0.01 parts by weight and 3 parts by weight, respectively.

[0119] As the film substrate, a transversely extended film (ZeonoR Film (registered trademark) ZT12-50135 manufactured by Zeon Corporation, Japan, thickness: 52 μm, in-plane retardation: 50 nm) was used. The aforementioned liquid crystal composition was coated onto the surface of the film substrate using a rod coater to a thickness of 1.4 μm after heating. The substrate was then heated at 100°C for 3 minutes to orient the liquid crystal compound. Subsequently, the liquid crystal composition on the film substrate was cooled to room temperature (25°C), and then photocured by irradiating the liquid crystal composition with ultraviolet light at a cumulative intensity of 400 mJ / cm² in a nitrogen atmosphere, resulting in a laminate L-1 with a horizontally aligned liquid crystal layer formed on the film substrate.

[0120] The in-plane retardation of the aligned liquid crystal layer in the obtained laminate L-1 was measured. Specifically, firstly, a 15 μm thick acrylic adhesive sheet was bonded to the surface of the aligned liquid crystal layer in laminate L-1, and then the adhesive sheet was bonded to a glass plate to obtain a laminate attached to the glass plate. Next, the film substrate was peeled off from the laminate attached to the glass plate to obtain a test sample. Then, the in-plane retardation of the test sample (aligned liquid crystal layer) at a wavelength of 590 nm was measured using a phase difference meter (KOBRA 21-ADH manufactured by Oji Ketsugi Co., Ltd.). Hereinafter, the in-plane retardation measured here is recorded as Re1. Re1 is 140 nm.

[0121] <Fabrication of Alignment Liquid Crystal Film> [Example 1: Fabrication of Alignment Liquid Crystal Film] A film ("MCP-N(100)" manufactured by Dai Nippon Printing Co., Ltd., hereinafter referred to as "Laminated Body L-2") with a vertically aligned liquid crystal layer (thickness: 3 μm, in-plane retardation: 0 nm) as an optical layer was prepared on a substrate. Furthermore, laminated body L-1 was fabricated by the above method.

[0122] The adhesive A-1 (temperature: 25°C) was coated onto the surface of the alignment liquid crystal layer of the laminate L-1 with a thickness of 1.0 μm, forming a layer containing the cured adhesive A-1. Then, the alignment liquid crystal layer side of the laminate L-2 was bonded onto the coated layer containing adhesive A-1 to obtain the laminate L-3.

[0123] Subsequently, following a roll-to-roll bonding process, adhesive A-1 in laminate L-3 is photocured while tension is applied to laminate L-3. Specifically, under an atmosphere of 25°C, laminate L-3 is subjected to a tension of 538 N / 1000 mm in a direction orthogonal to the alignment direction of the horizontally aligned liquid crystal layer in laminate L-1. Ultraviolet light is then applied using a high-pressure mercury lamp with an illuminance of 600 mW / cm² and a cumulative light intensity of 600 mJ / cm² to photocur adhesive A-1. Ultraviolet irradiation is performed from the laminate L-2 side. Furthermore, the alignment direction of the horizontally aligned liquid crystal layer in laminate L-1 is the extension direction of the film substrate (laterally extended film) of laminate L-1. Therefore, in the roll-to-roll bonding step, the direction orthogonal in-plane to the alignment direction of the horizontally aligned liquid crystal layer is the transport direction of the laminate L-3.

[0124] Subsequently, the substrate of laminate L-2 was peeled off from laminate L-3 to obtain the alignment liquid crystal film of Example 1. For the alignment liquid crystal film of Example 1, the mass of residual monomers in the adhesive layer was measured by LC / MS, and the adhesive reaction rate was determined. In the alignment liquid crystal film of Example 1, the adhesive reaction rate was 99%. Furthermore, for the alignment liquid crystal films of Examples 2-14 and Comparative Examples 1-3 described later, the mass of residual monomers in the adhesive layer was also measured by LC / MS, and the adhesive reaction rate was determined. For any alignment liquid crystal film in Examples 2-14 and Comparative Examples 1-3, the adhesive reaction rate was 99%.

[0125] [Fabrication of alignment liquid crystal films in Examples 2-6 and Comparative Examples 1-3] The type of adhesive was changed as shown in Table 2 below. Otherwise, alignment liquid crystal films of Examples 2-4 and Comparative Examples 1-3 were prepared using the same method as in Example 1. Furthermore, the type of adhesive was changed as shown in Table 2 below, and the adhesive layer was coated in such a way that its thickness was the same as that described in Table 2 below. Otherwise, alignment liquid crystal films of Examples 5 and 6 were prepared using the same method as in Example 1.

[0126] [Fabrication of Alignment Liquid Crystal Films in Examples 7-9] The cumulative light intensity during photocuring of the adhesive was changed as shown in Table 3 below. Otherwise, alignment liquid crystal films of Examples 7 to 9 were prepared using the same method as in Example 1. Furthermore, for reference, the details of Example 1 described above are also recorded in Table 3.

[0127] [Fabrication of Alignment Liquid Crystal Films in Examples 10-12] The temperature of the adhesive during coating was changed as shown in Table 4 below. Otherwise, alignment liquid crystal films of Examples 10-12 were prepared using the same method as in Example 1. Furthermore, for reference, the details of Example 1 are also recorded in Table 4.

[0128] [Fabrication of Alignment Liquid Crystal Films in Examples 13 and 14] The tension applied to the laminate L-3 was modified as shown in Table 5 below. Otherwise, the alignment liquid crystal films of Examples 13 and 14 were fabricated using the same method as in Example 1. Furthermore, for reference, the details of Example 1 described above are also recorded in Table 5.

[0129] <Evaluation> [Followed by changes in delay before and after] An acrylic adhesive sheet with a thickness of 15 μm was bonded to the surface of the vertically aligned liquid crystal layer of the alignment liquid crystal film of the evaluation object (any of the alignment liquid crystal films of Examples 1-14 and Comparative Examples 1-3). The adhesive sheet was then bonded to a glass plate to obtain a laminate attached to the glass plate. Next, the film substrate was peeled off from the laminate attached to the glass plate to obtain an evaluation sample. Then, the in-plane retardation of the evaluation sample (horizontally aligned liquid crystal layer) at a wavelength of 590 nm was measured using a phase difference meter (KOBRA 21-ADH manufactured by Oji Keiseki Co., Ltd.). Hereinafter, the in-plane retardation measured here is recorded as Re2. Then, the retardation change before and after bonding (unit: nm) was calculated according to the formula "Retardation change before and after bonding = |Re2 - Re1|". Furthermore, |Re2 - Re1| represents the absolute value of the difference between Re2 and Re1. When the delay change before and after the joint is less than 3.2 nm, it is evaluated as "able to suppress the delay change before and after the joint". On the other hand, when the delay change before and after the joint exceeds 3.2 nm, it is evaluated as "unable to suppress the delay change before and after the joint".

[0130] Furthermore, for the alignment liquid crystal film of Example 1, according to the formula "birefringence Δn = Re2 / thickness of horizontal alignment liquid crystal layer", the birefringence Δn is calculated from Re2 and the thickness of the horizontal alignment liquid crystal layer. The result is that the birefringence Δn of the horizontal alignment liquid crystal layer is 0.10.

[0131] [Rate of delayed change before and after heating durability test] The evaluation sample used in the above evaluation of [the change in delay before and after] was placed in an air-circulating constant-temperature oven at 85°C for 120 hours. Then, the evaluation sample was removed from the oven, and the in-plane delay of the evaluation sample (horizontally aligned liquid crystal layer) at a wavelength of 590 nm was measured using a phase difference meter (KOBRA 21-ADH manufactured by Oji Measurement & Control Co., Ltd.). Hereinafter, the in-plane delay measured here is recorded as Re3. Then, the rate of change in delay before and after the heat durability test (unit: %) was calculated according to the formula: "Rate of change in delay before and after the heat durability test = 100 × |Re3 - Re2| / Re2". Furthermore, |Re3 - Re2| represents the absolute value of the difference between Re3 and Re2. When the rate of change in delay before and after the heat durability test is 3.5% or less, it is evaluated as "the optical properties can be suppressed even after prolonged exposure to a high-temperature environment". On the other hand, when the rate of delayed change before and after the heating durability test exceeds 3.5%, it is evaluated as "failing to suppress the change in optical properties when exposed to a high-temperature environment for a long time".

[0132] Furthermore, no interlayer delamination occurred in the evaluation samples after the heat durability test, ensuring the reliability of the bonding.

[0133] For each of the above embodiments and comparative examples, the delay changes before and after the connection and the delay change rate before and after the heating durability test, along with the manufacturing conditions, are shown in Tables 2 to 5. Furthermore, in Tables 2 to 5, "ΔRe" represents the delay change before and after the connection, and "Re change rate" represents the delay change rate before and after the heating durability test.

[0134] [Table 2] Adhesive Adhesive layer thickness [μm] ΔRe [nm] Rate of change of Re [%] type hardening shrinkage [%] Example 1 A-1 11 1.0 3.0 3.2 Example 2 A-2 9 1.0 2.5 3.0 Example 3 A-3 7 1.0 2.0 3.0 Example 4 A-4 5 1.0 1.8 3.0 Example 5 A-4 5 0.5 1.6 2.9 Example 6 A-4 5 2.8 2.3 3.2 Comparative Example 1 A-5 15 1.0 3.7 3.8 Comparative Example 2 A-6 13 1.0 3.4 3.7 Comparative Example 3 A-7 12 1.0 3.3 3.6

[0135] [Table 3] Adhesive Cumulative light [mJ / cm 2] ΔRe [nm] Rate of change of Re [%] type hardening shrinkage [%] Example 7 A-1 11 450 2.8 2.7 Example 1 A-1 11 600 3.0 3.2 Example 8 A-1 11 800 3.0 3.3 Example 9 A-1 11 1100 3.1 3.5

[0136] [Table 4] Adhesive Adhesive temperature [℃] ΔRe [nm] Rate of change of Re [%] type hardening shrinkage [%] Example 10 A-1 11 0 2.7 2.8 Example 11 A-1 11 10 2.8 2.9 Example 1 A-1 11 25 3.0 3.2 Example 12 A-1 11 45 3.1 3.3

[0137] [Table 5] Adhesive tension [N / 1000 mm width] ΔRe [nm] Rate of change of Re [%] type hardening shrinkage [%] Example 1 A-1 11 538 3.0 3.2 Example 13 A-1 11 231 2.9 3.1 Example 14 A-1 11 77 2.7 2.8

[0138] As shown in Tables 2-5, adhesives with a curing shrinkage rate of less than 11% were used in Examples 1-14. In Examples 1-14, the rate of change in retardation before and after the heat durability test was less than 3.5%. Therefore, the alignment liquid crystal films of Examples 1-14 successfully suppressed changes in optical properties even after prolonged exposure to high temperatures.

[0139] As shown in Table 2, in Comparative Examples 1-3, adhesives with a curing shrinkage rate exceeding 11% were used. In Comparative Examples 1-3, the rate of retardation change before and after the heat durability test exceeded 3.5%. Therefore, the alignment liquid crystal films of Comparative Examples 1-3 failed to suppress the changes in optical properties when exposed to high-temperature environments for extended periods.

[0140] The above results demonstrate that the method for manufacturing alignment liquid crystal films according to the present invention can produce alignment liquid crystal films with minimal changes in optical properties even when exposed to high-temperature environments for extended periods.

[0141] 10: Film containing alignment liquid crystal layer 11: Coating device 12: Coating layer 13: Film containing optical layer 14: Guide rollers 15: First bonding roller 16: Second bonding roller 17: Laminated body 18: Active Energy Line Irradiation Device 19: Adhesive layer 20: Supporting substrate 21: Alignment liquid crystal layer 22: Optical layer 23: Supporting substrate 30: Adhesive layer 31: Peeling the liner 40: Adhesive layer 41: Optical layer 50: Image display unit 100:Alignment liquid crystal film 101:Aligned liquid crystal film 102:Alignment liquid crystal film 103:Alignment liquid crystal film 104:Alignment liquid crystal film 200: Image display device

Claims

1. A method for manufacturing an aligned liquid crystal film, comprising an aligned liquid crystal layer having an aligned liquid crystal compound aligned therewith, and a bonding step wherein the aligned liquid crystal layer and an optical layer are bonded in a roll-to-roll manner using an active energy line curing adhesive, wherein the curing shrinkage rate of the adhesive is 11% or less, and the thickness of the layer containing the adhesive after the irradiation step is 0.1 μm or more and 1.0 μm or less.

2. The method for manufacturing an alignment liquid crystal film as claimed in claim 1, wherein the bonding step includes an irradiation step, in which active energy lines are irradiated onto a laminate formed by laminating the alignment liquid crystal layer and the optical layer with the adhesive before curing, under tension. In the irradiation step, the active energy lines are irradiated onto the laminate under tension of 70 N / 1000 mm or more and 550 N / 1000 mm or more along the transport direction of the laminate.

3. A method for manufacturing an alignment liquid crystal film as claimed in claim 1 or 2, wherein the bonding step includes a coating step, which involves coating at least one surface of the alignment liquid crystal layer and the optical layer with the adhesive before curing, wherein the adhesive at a temperature of 0°C to 45°C is coated on the surface in the coating step.

4. A method for manufacturing an alignment liquid crystal film as claimed in claim 1 or 2, wherein the bonding step includes an irradiation step, in which an active energy line is irradiated onto a laminate formed by laminating the alignment liquid crystal layer and the optical layer with the adhesive before curing, while the laminate is under tension, wherein the active energy line is irradiated onto the laminate under conditions of a cumulative light intensity of 450 mJ / cm2 or more and 1200 mJ / cm2 or less.

5. The method for manufacturing an alignment liquid crystal film as claimed in claim 1 or 2, wherein the adhesive prior to curing comprises an oligomer with a weight average molecular weight of 1000 or more.

6. The method for manufacturing the alignment liquid crystal film as claimed in claim 5, wherein the content ratio of the oligomer with a weight average molecular weight of 1000 or more to the total amount of the adhesive before curing is 9.0% by weight or more and 20.0% by weight or less.

7. A method for manufacturing an aligned liquid crystal film as claimed in claim 1 or 2, wherein the liquid crystal compound in the aligned liquid crystal layer is horizontally aligned.

8. The method for manufacturing an alignment liquid crystal film as claimed in claim 7, wherein the birefringence Δn of the alignment liquid crystal layer after the above-mentioned bonding step is 0.03 or more.

9. A method for manufacturing an alignment liquid crystal film as claimed in claim 1 or 2, wherein the optical layer is a polarizing element, a transparent film, or other alignment liquid crystal layer.

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