Method for manufacturing an oriented liquid crystal film

Abstract

The oriented liquid crystal film (101) of the present application has a liquid crystal layer (1) in which liquid crystal molecules are oriented. In one embodiment, in the oriented liquid crystal layer, the liquid crystal molecules are oriented in parallel. The oriented liquid crystal layer can include a photocured product of a photopolymerizable liquid crystal compound. In the method of manufacturing the oriented liquid crystal film, surface treatment is performed in which an organic solvent is brought into contact with the surface of the oriented liquid crystal layer. After the surface treatment, the organic solvent can be removed by heating. The oriented liquid crystal layer (1) after the surface treatment can be attached to an optical layer (4) via an adhesive.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing a liquid crystal film in which liquid crystal molecules are oriented. BACKGROUND

[0002] As an optical film having a function of optically compensating a liquid crystal display device, preventing reflection of external light of an organic EL element, and the like, a liquid crystal film in which a liquid crystal compound is oriented in a prescribed direction (an oriented liquid crystal film) is used. The oriented liquid crystal film has a large birefringence compared to a stretched film of a polymer, and is thus advantageous in terms of thinness and lightness. In an image display device, the oriented liquid crystal film is attached to an organic EL panel, a liquid crystal display panel, as a polarizing plate which is layered with a polarizer integrally via an adhesive (a pressure-sensitive adhesive) or an adhesive agent (for example, Patent Document 1).

[0003] A liquid crystal compound can be oriented in a prescribed direction by a shearing force at the time of coating on a substrate, an orientation restricting force of an orientation film, and the like, and an oriented liquid crystal film having various optical anisotropies can be obtained. For example, a parallel orientation (horizontal orientation) liquid crystal layer in which nematic liquid crystal molecules having a positive refractive index anisotropy are oriented in parallel with the substrate surface can be used as a positive A plate having a refractive index anisotropy of nx>ny=nz.

[0004] In the case of using a thermotropic liquid crystal, a solution (a liquid crystalline composition) containing a liquid crystal compound is coated on a substrate, and the liquid crystal molecules are oriented by heating in such a manner that the compound contained in the composition becomes a liquid crystal state. In the case where the liquid crystalline composition contains a liquid crystal compound (a liquid crystal monomer) having photopolymerizability, after the liquid crystal molecules are oriented, the liquid crystal monomer is cured by irradiation with light, and thus the oriented state is fixed.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-7700 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] For an image display device such as a liquid crystal display device or an organic EL display device, higher durability is required, and it is required that an optical member constituting the image display device has a small change in optical characteristics even when exposed to a high-temperature environment for a long time. In the above-described Patent Document 1, it is described that by controlling an orientation parameter of a liquid crystal compound, a change in phase retardation of an oriented liquid crystal film under a high-temperature environment can be reduced.

[0010] The optical properties of an alignment liquid crystal film sometimes change in a high temperature environment, not only due to the influence of the alignment state of the liquid crystal, but also due to the influence of a layer disposed adjacent to the liquid crystal layer. For example, in the case where an alignment liquid crystal layer is attached to a polarizer via an adhesive layer (a pressure-sensitive adhesive layer), almost no retardation change occurs in a high temperature environment, whereas a sample in which an alignment liquid crystal layer is attached to a polarizer via an ultraviolet-curable adhesive exhibits a tendency to have a retardation increase in a high temperature environment.

[0011] In view of the above problem, an object of the present application is to provide an alignment liquid crystal film which has a small change in optical properties even when exposed to a high temperature environment for a long time, and which has excellent heat durability.

[0012] Means for solving the problem

[0013] The alignment liquid crystal film has an alignment liquid crystal layer in which liquid crystal molecules are aligned in a prescribed direction. The alignment liquid crystal layer is formed, for example, by the steps of: applying a liquid crystalline composition containing a photopolymerizable liquid crystal monomer onto a support substrate, heating the liquid crystalline composition on the support substrate to align the liquid crystal monomers in a liquid crystal state, and polymerizing or crosslinking the liquid crystal monomers by light irradiation.

[0014] In one embodiment of the present application, surface treatment is performed in which an organic solvent is brought into contact with the surface of the alignment liquid crystal layer. In the surface treatment, for example, an organic solvent which has solubility with respect to the photopolymerizable liquid crystal monomer and which is insoluble or hardly soluble with respect to the photocured product of the photopolymerizable liquid crystal monomer is used. A small amount of a resin component can be contained in the liquid used in the surface treatment.

[0015] Heating can be performed after the surface treatment to remove the organic solvent from the surface of the alignment liquid crystal layer. The heating temperature is, for example, 40 to 150°C.

[0016] Further, the alignment liquid crystal layer after the surface treatment can be attached to an optical layer via an adhesive. As the optical layer, a polarizer, a transparent film, an alignment liquid crystal layer, and the like can be exemplified. The adhesive used in the attachment of the alignment liquid crystal layer to the optical layer can be an active energy ray-curable adhesive.

[0017] Effects of the Invention

[0018] The alignment liquid crystal film of the present application has excellent heat durability, and has a small change in retardation even when exposed to a high temperature environment for a long time. Therefore, it is suitable as an optical member for an image display device such as a liquid crystal display device or an organic EL display device. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a cross-sectional view of an alignment liquid crystal film having a liquid crystal layer on a support substrate.

[0020] Figure 2is a cross-sectional view of an oriented liquid crystal film in which an optical layer is laminated on the surface of a liquid crystal layer.

[0021] Figure 3 is a cross-sectional view of an oriented liquid crystal film in which an optical layer is laminated on the surface of a liquid crystal layer.

[0022] Figure 4 is a cross-sectional view of an oriented liquid crystal film provided with an adhesive layer.

[0023] Figure 5 is a cross-sectional view of an oriented liquid crystal film in which an optical layer is laminated on the surface of a liquid crystal layer.

[0024] Figure 6 is a cross-sectional view showing a lamination example of an image display device. DETAILED DESCRIPTION

[0025] The oriented liquid crystal film includes a liquid crystal layer in which liquid crystal molecules are oriented. Figure 1 is a cross-sectional view showing the configuration of an oriented liquid crystal film according to one embodiment. The oriented liquid crystal film 101 is provided with an oriented liquid crystal layer 1 on a support substrate 8. The oriented liquid crystal layer 1 is formed by applying a liquid crystalline composition containing a liquid crystal compound on the support substrate 8, orienting the liquid crystal compound in a prescribed direction, and then fixing the oriented state.

[0026] <LIQUID CRYSTALLINE COMPOSITION>

[0027] As the liquid crystal compound, rod-like liquid crystal compounds and disc-like liquid crystal compounds, etc. can be exemplified. From the viewpoint that the liquid crystal compound is easily oriented in parallel by the orientation restricting force of the support substrate, the liquid crystal compound is preferably a rod-like liquid crystal compound. The rod-like liquid crystal compound can be a main chain type liquid crystal or a side chain type liquid crystal. The rod-like liquid crystal compound can be a liquid crystal polymer or a polymer of a polymerizable liquid crystal compound. As long as the liquid crystal compound (monomer) before polymerization exhibits liquid crystallinity, the liquid crystal compound can not exhibit liquid crystallinity after polymerization.

[0028] The liquid crystal compound is preferably a thermotropic liquid crystal which exhibits liquid crystallinity by heating. The thermotropic liquid crystal undergoes phase transition of crystalline phase, liquid crystal phase, isotropic phase with temperature change. The liquid crystal compound contained in the liquid crystalline composition can be any one of nematic liquid crystal, smectic liquid crystal, and cholesteric liquid crystal. A chiral agent can be added to the nematic liquid crystal to impart cholesteric orientation property.

[0029] As the rod-like liquid crystal compound exhibiting thermotropism, azomethine compounds, oxoazo compounds, cyanobiphenyl compounds, cyanophenyl ester compounds, benzoate compounds, cyclohexane carboxylic acid phenyl ester compounds, cyanophenyl cyclohexane compounds, cyano-substituted phenyl pyrimidine compounds, alkoxy-substituted phenyl pyrimidine compounds, phenyl dioxane compounds, diphenyl acetylene compounds, alkenyl cyclohexyl benzonitrile compounds, etc. can be exemplified.

[0030] As the polymerizable liquid crystal compound, for example, a polymerizable liquid crystal compound which can be used with a polymer binder to fix the alignment state of a rod-like liquid crystal compound, a polymerizable liquid crystal compound having a polymerizable functional group which can fix the alignment state of a liquid crystal compound by polymerization, and the like can be exemplified. Among them, a photopolymerizable liquid crystal compound having a photopolymerizable functional group is preferred.

[0031] The photopolymerizable liquid crystal compound (liquid crystal monomer) has a mesogenic group and at least one photopolymerizable functional group in one molecule. The temperature at which the liquid crystal monomer exhibits liquid crystallinity (liquid crystal phase transition temperature) is preferably 40 to 200°C, more preferably 50 to 150°C, and further preferably 55 to 100°C.

[0032] As the mesogenic group of the liquid crystal monomer, a cyclic structure such as a biphenyl group, a phenyl benzoate group, a phenylcyclohexane group, an oxazobenzene group, an azomethine group, an azobenzene group, a phenylpyrimidine group, a diphenyl acetylene group, a diphenyl benzoate group, a bicyclohexane group, a cyclohexylphenyl group, a terphenyl group, and the like can be exemplified. The terminal of these cyclic units can have a cyano group, an alkyl group, an alkoxy group, a halogen group, or the like as a substituent.

[0033] As the photopolymerizable functional group, a (meth)acryloyl group, an epoxy group, a vinyl ether group, and the like can be exemplified. Among them, a (meth)acryloyl group is preferred. The photopolymerizable liquid crystal monomer is preferably one having two or more photopolymerizable functional groups in one molecule. By using a liquid crystal monomer containing two or more photopolymerizable functional groups, a crosslinked structure is introduced into the liquid crystal layer after photocuring, and thus there is a tendency that the durability of the aligned liquid crystal film is improved.

[0034] As the photopolymerizable liquid crystal monomer, any appropriate liquid crystal monomer can be used. For example, the compounds described in International Publication No. 00 / 37585, U.S. Patent No. 5211877, U.S. Patent No. 4388453, International Publication No. 93 / 22397, European Patent No. 0261712, German Patent No. 19504224, German Patent No. 4408171, British Patent No. 2280445, Japanese Patent Application Laid-Open No. 2017-206460, International Publication No. 2014 / 126113, International Publication No. 2016 / 114348, International Publication No. 2014 / 010325, Japanese Patent Application Laid-Open No. 2015-200877, Japanese Patent Application Laid-Open No. 2010-31223, International Publication No. 2011 / 050896, Japanese Patent Application Laid-Open No. 2011-207765, Japanese Patent Application Laid-Open No. 2010-31223, Japanese Patent Application Laid-Open No. 2010-270108, International Publication No. 2008 / 119427, Japanese Patent Application Laid-Open No. 2008-107767, Japanese Patent Application Laid-Open No. 2008-273925, International Publication No. 2016 / 125839, Japanese Patent Application Laid-Open No. 2008-273925, and the like can be exemplified. By selecting the liquid crystal monomer, the appearance of birefringence and the wavelength dispersion of the retardation can be adjusted.

[0035] In addition to the liquid crystal monomer, a compound that controls the orientation of the liquid crystal monomer in a predetermined direction can be contained in the liquid crystal composition. For example, by containing a side chain type liquid crystal polymer in the liquid crystal composition, the liquid crystal compound (monomer) can be vertically oriented. In addition, by adding a chiral agent to the liquid crystal composition, the liquid crystal compound can be oriented in a cholesteric type.

[0036] The liquid crystal composition can contain a photopolymerization initiator. In the case where the liquid crystal monomer is cured by ultraviolet irradiation, in order to promote photocuring, the liquid crystal composition preferably contains a photopolymerization initiator (a photoradical generator) that generates radicals by light irradiation. Depending on the kind of the liquid crystal monomer (the kind of the photopolymerizable functional group), a photocation generator or a photanion generator can be used. The amount of the photopolymerization initiator used is about 0.01 to 10 parts by weight with respect to 100 parts by weight of the liquid crystal monomer. In addition to the photopolymerization initiator, a sensitizer or the like can be used.

[0037] The liquid crystalline composition can be prepared by mixing the liquid crystal monomer and, as necessary, various alignment control agents, polymerization initiators, and the like with a solvent. The solvent is not particularly limited as long as it can dissolve the liquid crystal monomer and does not erode the substrate (or is low in erodibility), and examples thereof include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and o-dichlorobenzene; phenols such as phenol and p-chlorophenol; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, and 1,2-dimethoxybenzene; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, and N-methyl-2-pyrrolidone; ester-based solvents such as ethyl acetate and butyl acetate; alcohol-based solvents such as t-butyl alcohol, glycerol, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, and 2-methyl-2,4-pentanediol; amide-based solvents such as dimethylformamide and dimethylacetamide; nitrile-based solvents such as acetonitrile and butyronitrile; ether-based solvents such as diethyl ether, dibutyl ether, and tetrahydrofuran; and ethyl cellosolve and butyl cellosolve. A mixed solvent of two or more solvents can be used.

[0038] The solid content concentration of the liquid crystalline composition is usually about 5 to 60% by weight. The liquid crystalline composition can contain additives such as a surfactant and a leveling agent.

[0039] <Supporting substrate>

[0040] As the supporting substrate 8 on which the liquid crystalline composition is applied, a glass plate, a metal plate, a metal belt, a resin film substrate, or the like can be used. The supporting substrate has a first main surface and a second main surface, and the liquid crystalline composition is applied on the first main surface.

[0041] By using a film substrate as the supporting substrate 8, the application of the liquid crystalline composition on the substrate, the photocuring of the liquid crystal monomer, and the subsequent heating treatment can be performed in a roll-to-roll manner, and thus the productivity of the aligned liquid crystal film can be improved. The resin material constituting the film substrate is not particularly limited as long as it is not dissolved in the solvent of the liquid crystalline composition and has heat resistance at the time of heating for aligning the liquid crystalline composition, and examples thereof include polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; cyclic polyolefins such as norbornene-based polymers; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; acrylic polymers; styrene-based polymers; polycarbonates; polyamides; and polyimides.

[0042] The support substrate 8 can have an alignment capability for aligning liquid crystal molecules in a prescribed direction. For example, by using a stretched film as the support substrate, liquid crystal molecules can be aligned in parallel along the direction of stretching thereof. The stretching ratio of the stretched film can be, for example, about 1.1 to 5 times, as long as it is a degree that the alignment capability can be exerted. The stretched film can be a biaxially stretched film. Even if it is a biaxially stretched film, if the stretching ratio in the longitudinal direction is different from that in the lateral direction, liquid crystal molecules can be aligned in the direction of the larger stretching ratio. The stretched film can be an obliquely stretched film. By using a stretched film as the support substrate 8, liquid crystal molecules can be aligned in a direction that is not parallel to neither the longitudinal direction nor the lateral direction of the support substrate.

[0043] The support substrate 8 can have an alignment film on the first main surface. The alignment film can be appropriately selected depending on the kind of the liquid crystal compound, the material of the substrate, and the like. As the alignment film for aligning liquid crystal molecules in parallel in a prescribed direction, it is preferable to use one obtained by rubbing treatment of a polyimide-based or polyvinyl alcohol-based alignment film. Alternatively, an optical alignment film can be used. The rubbing treatment can be performed on the resin film as the support substrate without providing the alignment film.

[0044] The support substrate 8 can have an alignment film for vertically aligning liquid crystal molecules. As the alignment agent for forming a vertical alignment property (vertical alignment film), lecithin, stearic acid, cetyltrimethylammonium bromide, octadecylamine hydrochloride, an alkaline chromium carboxylate complex, an organic silane such as a silane coupling agent or a siloxane compound, perfluorodimethylcyclohexane, tetrafluoroethylene, polytetrafluoroethylene, and the like can be exemplified.

[0045] Formation of an aligned liquid crystal layer on a support substrate

[0046] In the case where the liquid crystal compound is a thermotropic liquid crystal, the liquid crystalline composition is applied to the first main surface of the support substrate 8, and the liquid crystal compound is aligned in a liquid crystal state by heating.

[0047] The method of applying the liquid crystalline composition to the support substrate 8 is not particularly limited, and spin coating, die coating, roll coating, gravure coating, reverse coating, spray coating, wire bar coating, knife-over-roll coating, air-knife coating, and the like can be used. After the solution is applied, a liquid crystalline composition layer is formed on the support substrate by removing the solvent. The application thickness is preferably adjusted so that the thickness of the liquid crystalline composition layer after the solvent is dried (the thickness of the aligned liquid crystal film) becomes about 0.1 to 20 μm.

[0048] The liquid crystal compound is oriented by heating the liquid crystal composition layer formed on the support substrate to become a liquid crystal phase. Specifically, after the liquid crystal composition is applied to the support substrate, the liquid crystal composition is heated to a temperature above the N (nematic) -I (isotropic liquid) transition temperature of the liquid crystal composition to make the liquid crystal composition into an isotropic liquid state. Thereafter, the nematic phase is exhibited by slow cooling as necessary. At this time, the temperature at which the liquid crystal phase is temporarily exhibited is desirably maintained to grow the liquid crystal phase domains to become a single domain. Alternatively, after the liquid crystal composition is applied to the support substrate, the temperature can be maintained for a certain period of time within the temperature range in which the nematic phase is exhibited to orient the liquid crystal molecules in a prescribed direction.

[0049] The heating temperature at which the liquid crystal compound is oriented in a prescribed direction is appropriately selected depending on the type of the liquid crystal composition, and is usually around 40 to 200°C. If the heating temperature is too low, the transition to the liquid crystal phase tends to be insufficient, and if the heating temperature is too high, the orientation defects increase. The heating time is adjusted so that the liquid crystal phase domains sufficiently grow, and is usually around 30 seconds to 30 minutes.

[0050] After the liquid crystal compound is oriented by heating, the temperature is desirably cooled to a temperature below the glass transition temperature. The cooling method is not particularly limited, and for example, the heating atmosphere can be removed to room temperature. Forced cooling such as air cooling or water cooling can be performed.

[0051] The liquid crystal layer is subjected to light irradiation to perform photo-curing in a state in which the photopolymerizable liquid crystal compound (liquid crystal monomer) has liquid crystal regularity. The irradiation light is light that can polymerize the photopolymerizable liquid crystal compound, and ultraviolet light or visible light having a wavelength of 250 to 450 nm is usually used. In the case where the liquid crystal composition contains a photopolymerization initiator, light having a wavelength to which the photopolymerization initiator has sensitivity is selected. As the light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, an LED (Light Emitting Diode), a black light, a chemical lamp, or the like can be used. In order to promote the photo-curing reaction, the light irradiation is desirably performed in an inert gas atmosphere such as nitrogen.

[0052] At the time of photo-curing of the liquid crystal composition, the liquid crystal compound can also be oriented in a prescribed direction by using polarized light in the prescribed direction. As described above, in the case where the liquid crystal compound is oriented by the orientation restriction force of the support substrate 8, the irradiation light can be non-polarized light (natural light).

[0053] The irradiation intensity is appropriately adjusted depending on the composition of the liquid crystal composition, the amount of the photopolymerization initiator added, and the like. The irradiation energy (cumulative amount of irradiation light) is usually 20 to 10,000 mJ / cm 2left and right, preferably 50 to 5000 mJ / cm 2 more preferably 100 to 800 mJ / cm 2 In order to promote the photocuring reaction, the light irradiation can be performed under heating.

[0054] The polymer after the liquid crystal monomer is photocured by light irradiation is non-liquid crystalline, and does not undergo a transition of the liquid crystal phase, glass phase, or crystalline phase caused by a change in temperature. Therefore, the liquid crystal layer in which the liquid crystal monomer is photocured in a state in which the liquid crystal monomer is oriented in a prescribed direction is less likely to undergo a change in molecular orientation caused by a change in temperature. In addition, since the oriented liquid crystal film has a very large birefringence compared to a film formed of a non-liquid crystalline material, the thickness of the optically anisotropic element having a desired retardation can be significantly reduced. The thickness of the oriented liquid crystal film (liquid crystal layer) can be set as appropriate in accordance with the target retardation value or the like, and is typically about 0.1 to 20 μm, preferably 0.2 to 10 μm, and more preferably 0.5 to 7 μm.

[0055] The optical properties of the oriented liquid crystal layer are not particularly limited. The front retardation and the thickness direction retardation of the oriented liquid crystal layer can be appropriately set in accordance with the use or the like. In the case of liquid crystal parallel orientation, the front retardation of the oriented liquid crystal layer is, for example, about 20 to 1000 nm. In the case where the oriented liquid crystal layer is a 1 / 4 wavelength plate, the front retardation is preferably 100 to 180 nm, and more preferably 120 to 150 nm. In the case where the oriented liquid crystal layer is a 1 / 2 wavelength plate, the front retardation is preferably 200 to 340 nm, and more preferably 240 to 300 nm. In the case of liquid crystal perpendicular orientation, the in-plane retardation of the oriented liquid crystal layer is substantially 0 (for example, 5 nm or less, and preferably 3 nm or less), and the absolute value of the thickness direction retardation is about 30 to 500 nm.

[0056] (Surface treatment)

[0057] As described above, since the liquid crystal layer after photocuring does not undergo a phase transition even when heated, the heat stability is excellent compared to an oriented liquid crystal layer that has not been cured. However, if the liquid crystal layer after photocuring is exposed to a high temperature environment for a long period of time, there are cases in which the optical properties change, and there is room for improvement in heat resistance. In particular, an oriented liquid crystal film in which the oriented liquid crystal layer is bonded to other optical layers via an adhesive has a tendency for the retardation to increase when heated for a long period of time, and the heat resistance is problematic.

[0058] In the embodiments of the present application, surface treatment is performed by bringing an organic solvent into contact with the surface of the oriented liquid crystal layer after the orientation is fixed by photocuring or the like. By performing this surface treatment, the heat stability of the optical properties of the oriented liquid crystal layer is improved.

[0059] The organic solvent used in the surface treatment is not particularly limited, and is preferably one that does not dissolve the oriented liquid crystal layer. For example, in the case where the oriented liquid crystal layer contains a photocured product of a photopolymerizable liquid crystal monomer, an organic solvent that does not dissolve or hardly dissolves the cured product is preferred. On the other hand, the organic solvent can be one that exhibits solubility to the liquid crystal compound (monomer) before photocuring. The organic solvent can be one solvent, or a mixed solvent of two or more solvents.

[0060] The liquid used in the surface treatment can contain a resin component in addition to the organic solvent. The resin component can be one that is a liquid at ordinary temperature and becomes a solid resin by heat or light curing. However, in the case where the amount of the resin component is too large, the optical influence of the resin layer formed on the surface of the oriented liquid crystal layer becomes serious, and there is a risk of a decrease in transparency and the like. Therefore, the amount of the resin component contained in the liquid used in the surface treatment is preferably 15% by mass or less, more preferably 10% by mass or less, and can be 5% by mass or less or 3% by mass or less. In the case where the liquid used in the surface treatment contains a resin component, the glass transition temperature of the resin is preferably 20°C or higher, more preferably 30°C or higher, and can be 40°C or higher or 50°C or higher. In addition, the resin component is preferably a non-cured polymer that does not have photocuring and heat curing properties.

[0061] The method of bringing the above liquid into contact with the surface of the oriented liquid crystal layer is not particularly limited, and an immersion method and various coating methods can be appropriately used. The contact treatment time is not particularly limited, and from the viewpoint of improving the heat stability of the optical properties of the oriented liquid crystal layer, it is preferably 10 seconds or more, and more preferably 20 seconds or more. In the case where the treatment time is too long, there is a risk of a decrease in productivity and dissolution of the oriented liquid crystal layer in the organic solvent, and therefore the treatment time is preferably 60 minutes or less, more preferably 30 minutes or less, and further preferably 10 minutes or less, and can be 5 minutes or less or 3 minutes or less.

[0062] It is preferred that the organic solvent adhering to the surface of the oriented liquid crystal layer be removed after the surface treatment using the above liquid. The removal of the organic solvent is performed by heating, for example. From the viewpoint of the removal efficiency of the organic solvent, the heating temperature is preferably 40°C or higher, and more preferably 50°C or higher. In the case where the heating temperature is too high, there is a risk of a decrease in the heat stability of the oriented liquid crystal film due to thermal damage to the substrate, reorientation of the liquid crystal compound, and the like. Therefore, the heating temperature is preferably 150°C or lower, more preferably 130°C or lower, and can be 110°C or lower or 100°C or lower.

[0063] Surface cleaning can be performed using water or organic solvents instead of the aforementioned heating, or surface cleaning can be performed using water or organic solvents in addition to heating. By contacting the alignment liquid crystal layer with the organic solvent and cleaning the surface, monomers and additives precipitated from the alignment liquid crystal layer into the organic solvent can be removed, thus inhibiting contamination on the surface of the alignment liquid crystal layer.

[0064] The reason why surface treatment with organic solvents improves the heating durability of alignment liquid crystal layers is unclear, but one reason is believed to be that uncured monomers remaining in the photocured liquid crystal layer and free additives contained in the insufficiently formed three-dimensional network structure are dissolved by organic solvents and removed from the alignment liquid crystal layer, which are the substances that cause the delayed changes caused by heating.

[0065] In the above embodiment, in the alignment liquid crystal film 101 on the support substrate 8 where the alignment liquid crystal layer 1 is densely stacked, the process of contacting the organic solvent with the surface of the alignment liquid crystal layer 1 that is not in contact with the support substrate 8 (air surface) has been described. However, it is also possible to perform surface treatment with an organic solvent on the exposed surface of the alignment liquid crystal layer 1 after peeling off the support substrate 8 from the alignment liquid crystal layer 1. In addition, surface treatment with an organic solvent can also be performed on both sides of the alignment liquid crystal layer.

[0066] <Layering of optically aligned liquid crystal layers>

[0067] Alignment liquid crystal films are not limited to Figure 1 The scheme shown. For example, as Figure 2 As shown, the alignment liquid crystal film 102 may be formed by laminating other optical layers 4 on the surface of the alignment liquid crystal layer 1 that is not in contact with the support substrate 8 via a suitable adhesive layer 3 or adhesive layer.

[0068] There are no particular limitations on optical layer 4; any commonly used optically isotropic or optically anisotropic film can be used as the optical film without special restrictions. Specific examples of optical layer 4 include transparent films such as phase retardation films and polarizer protective films, as well as functional films such as polarizers, viewing angle widening films, viewing angle limiting (anti-spy) films, and brightness enhancement films. Optical layer 4 can be a single layer or a laminate. Optical layer 4 can be an aligned liquid crystal layer. For example, optical layer 4 can be a polarizer with a transparent protective film bonded to one or both sides of the polarizer. When the polarizer has a transparent protective film on one side, the polarizer can be bonded to the aligned liquid crystal layer, or the transparent protective film can be bonded to the aligned liquid crystal layer.

[0069] For example, in liquid crystal display devices, there are cases in which a phase difference sheet is disposed as an optical compensation film between an image display cell (liquid crystal cell) and a polarizer in order to appropriately change the polarization state of light emitted from the liquid crystal cell to the viewing side for the purpose of improving viewing angle characteristics and the like. In organic EL display devices, there are cases in which a 1 / 4 wavelength plate is disposed between a cell and a polarizing plate in order to suppress the appearance of a mirror surface when external light is reflected at a metal electrode layer.

[0070] As described above, after the surface of the alignment liquid crystal layer 1 is treated with an organic solvent, the optical layer 4 is attached, whereby the heat durability of the alignment liquid crystal layer 1 in the alignment liquid crystal film 102 can be improved. In particular, in the case where the optical layer 4 is attached to the surface of the alignment liquid crystal layer 1 after surface treatment via the adhesive layer 3, there is a tendency to significantly improve the heat durability of the alignment liquid crystal layer compared to the case where no surface treatment is performed.

[0071] The adhesive used for the adhesive layer 3 that constitutes the lamination of the alignment liquid crystal layer 1 and the optical layer 4 is only required to be optically transparent, and the material thereof is not particularly limited, and examples include epoxy resins, silicone resins, acrylic resins, polyurethanes, polyamides, polyethers, polyvinyl alcohols, and the like. The thickness of the adhesive layer 3 is, for example, about 0.01 to 20 μm, and is appropriately set according to the type of the adherend, the material of the adhesive, and the like. In the case where a cured adhesive that exhibits adhesiveness through cross-linking reaction after coating is used, the thickness of the adhesive layer 3 is preferably 0.01 to 5 μm, and more preferably 0.03 to 3 μm.

[0072] As the adhesive, various types of adhesives such as water-based adhesives, solvent-based adhesives, hot melt adhesive systems, active energy ray curable adhesives, and the like can be used. Among these, a water-based adhesive or an active energy ray curable adhesive is preferable in order to reduce the thickness of the adhesive layer.

[0073] As the water-based adhesive, for example, a water-soluble or water-dispersible polymer such as a vinyl polymer-based, gelatin-based, vinyl latex-based, polyurethane-based, isocyanate-based, polyester-based, epoxy-based, and the like can be exemplified. The adhesive layer formed from such a water-based adhesive is formed by coating an aqueous solution on a film and drying it. When the aqueous solution is prepared, a cross-linking agent, other additives, a catalyst such as an acid, and the like can be compounded as necessary.

[0074] As the cross-linking agent compounded in the water-based adhesive, examples include boric acid, borax; carboxylic acid compounds; alkyl diamines; isocyanates; epoxies; mono aldehydes; di aldehydes; amino-formaldehyde resins; salts of divalent or trivalent metals; oxides thereof; and the like.

[0075] The active energy ray-curable adhesive is an adhesive that can undergo radical polymerization, cationic polymerization, or anionic polymerization by irradiation of active energy rays such as electron beams, ultraviolet rays, and the like. Among these, from the standpoint of being able to perform curing with low energy, a photoradical polymerizable adhesive that initiates radical polymerization by ultraviolet irradiation is preferable.

[0076] As the monomer of the radical polymerizable adhesive, a (meth)acryl group-containing compound, a vinyl group-containing compound can be cited. Among these, a (meth)acryl group-containing compound is preferable. As the (meth)acryl group-containing compound, a (meth)acrylic acid C 1-20 alkyl (meth)acrylate; a (meth)acrylate having an epoxy group such as glycidyl (meth)acrylate; and the like. The radical polymerizable adhesive can contain a nitrogen-containing monomer such as hydroxyethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, (meth)acrylamide, and (meth)acryloyl morpholine. The radical polymerizable adhesive can contain a multifunctional monomer such as tripropyleneglycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO-modified diglycerol tetraacrylate as a crosslinking component.

[0077] The photo-curable adhesive such as the photoradical polymerizable adhesive preferably contains a photopolymerization initiator. The photopolymerization initiator can be appropriately selected depending on the reaction species. For example, in the radical polymerizable adhesive, a photoradical generator that generates radicals by light irradiation is preferably blended as the photopolymerization initiator. Specific examples of the photoradical generator will be described below. The content of the photoradical generator is usually about 0.1 to 10 parts by weight and preferably 0.5 to 3 parts by weight relative to 100 parts by weight of the monomer. Furthermore, in the case where the radical polymerizable adhesive is used in the form of an electron beam-curable adhesive, a photopolymerization initiator is not particularly required. In the radical polymerizable adhesive, a photosensitizer represented by a carbonyl compound or the like can also be added as necessary. The photosensitizer is used to improve the speed and sensitivity of curing by electron beams. The amount of the photosensitizer used is usually about 0.001 to 10 parts by weight and preferably 0.01 to 3 parts by weight relative to 100 parts by weight of the monomer.

[0078] The adhesive can contain appropriate additives as necessary. As examples of the additives, coupling agents such as silane coupling agents and titanium coupling agents, adhesion promoters such as ethylene oxide, ultraviolet absorbers, degradation preventives, dyes, processing aids, ion traps, antioxidants, tackifiers, fillers, plasticizers, leveling agents, foaming inhibitors, antistatic agents, heat-resistant stabilizers, hydrolysis-resistant stabilizers, and the like can be listed.

[0079] The oriented liquid crystal layer 1 and the optical layer 4 are laminated via the adhesive layer 3 by applying an adhesive to either or both of the surface of the oriented liquid crystal layer 1 and the surface of the optical layer 4 and curing the adhesive. The curing of the adhesive is appropriately selected depending on the type of the adhesive. For example, a water-based adhesive can be cured by heating. An active energy ray-curable adhesive can be cured by irradiation with active energy rays such as ultraviolet rays.

[0080] The oriented liquid crystal film 102 in which the optical layer 4 is laminated on the oriented liquid crystal layer 1 can be directly used as an optical member. In this case, the support substrate 8 constitutes a part of the oriented liquid crystal film. As shown in the oriented liquid crystal film 103, the support substrate can be peeled off from the oriented liquid crystal layer 1. As shown in the oriented liquid crystal film 104, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an appropriate adhesive layer 2. As shown in the oriented liquid crystal film 105, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an optical layer 5. Figure 3 Figure 4 As shown in the oriented liquid crystal film 103, the support substrate can be peeled off from the oriented liquid crystal layer 1. As shown in the oriented liquid crystal film 104, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an appropriate adhesive layer 2. As shown in the oriented liquid crystal film 105, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an optical layer 5. Figure 5 As shown in the oriented liquid crystal film 103, the support substrate can be peeled off from the oriented liquid crystal layer 1. As shown in the oriented liquid crystal film 104, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an appropriate adhesive layer 2. As shown in the oriented liquid crystal film 105, the surface of the oriented liquid crystal layer 1 exposed by peeling off the support substrate can be laminated with an optical layer 5.

[0081] The adhesive constituting the adhesive layer 2 is not particularly limited, and an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine polymer, a rubber polymer, or the like can be appropriately selected and used as a base polymer. An acrylic adhesive, a rubber adhesive, or the like is particularly preferable because of excellent transparency, moderate wettability, cohesiveness, and adhesiveness, and excellent weather resistance, heat resistance, and the like. The thickness of the adhesive layer is appropriately set depending on the type of the adherend, and is generally about 5 to 500 μm.

[0082] The lamination of the adhesive layer 2 on the oriented liquid crystal layer 1 is performed, for example, by adhering an adhesive previously formed in a sheet shape to the surface of the oriented liquid crystal layer 1. After the adhesive composition is applied to the oriented liquid crystal layer 1, drying of the solvent, crosslinking, photocuring, or the like can be performed to form the adhesive layer 2. In order to improve the adhesion (grip force) of the oriented liquid crystal layer 1 and the adhesive layer 2, a surface treatment such as corona treatment or plasma treatment or the formation of an easily adhering layer can be performed on the surface of the oriented liquid crystal layer 1, and then the adhesive layer 2 can be laminated.

[0083] ​The surface of the adhesive layer 2 is preferably temporarily bonded with a spacer 9. The spacer 9 protects the surface of the adhesive layer 2 during the period until the optical film with the adhesive is attached to the image display unit 50. As a material for the spacer, a plastic film such as an acrylic resin, a polyolefin, a cyclic polyolefin, a polyester, or the like is preferably used. The thickness of the spacer is usually about 5 to 200 μm. The surface of the spacer is preferably subjected to a release treatment. As a release agent, a silicone-based material, a fluorine-based material, a long-chain alkyl-based material, a fatty amide-based material, or the like can be used.

[0084] In Figure 4 the illustrated scheme, the exposed surface of the oriented liquid crystal layer 1 after the peeling of the support substrate 8 is laminated with the adhesive layer 2, and the adhesive layer can also be laminated on the air side of the oriented liquid crystal layer 1.

[0085] The exposed surface of the oriented liquid crystal layer 1 after the peeling of the support substrate 8 can be laminated with other optical layers via an appropriate adhesive layer or an adhesive layer. For example, as Figure 5 illustrated, other optical layers 5 can be laminated on the oriented liquid crystal layer 1 via an appropriate adhesive layer 7. An adhesive layer (not shown) can be further laminated on the optical layers 5, and a spacer can be temporarily bonded on the surface of the adhesive layer.

[0086] < Circular Polarizing Plate >

[0087] The oriented liquid crystal film can be used as an optical film for a display device for the purpose of improving visibility and the like. For example, in a liquid crystal display device, there is a case where a phase difference plate as an optical compensation film is disposed between an image display unit (liquid crystal cell) and a polarizer in order to appropriately change the polarization state of light emitted from the liquid crystal cell to the visibility side to improve the viewing angle characteristics and the like.

[0088] In one embodiment, the oriented liquid crystal film is a circular polarizing plate in which a polarizing plate as an optical layer 4 is attached to one surface of the oriented liquid crystal layer 1 via an adhesive layer 3. The circular polarizing plate can be one having two or more oriented liquid crystal layers.

[0089] The polarizing plate can be one formed of only one layer of a polarizer, and as described above, a transparent protective film can be attached to one or both surfaces of the polarizer. As the polarizer, there can be mentioned one obtained by adsorbing iodine, a dichroic dye, or the like, and uniaxially stretching a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, or the like; a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol, a dehydrochlorinated product of polyvinyl chloride, or the like.

[0090] Among these, a preferred polarizer, based on high polarization, is a polyvinyl alcohol (PVA)-based polarizer that orients itself in a specified direction by adsorbing iodine and dichroic substances such as dichroic dyes onto a polyvinyl alcohol film, such as polyvinyl alcohol or partially formalized polyvinyl alcohol. For example, a PVA-based polarizer can be obtained by iodizing and stretching a polyvinyl alcohol film. A PVA-based resin layer can be formed on a resin substrate, and iodine staining and stretching can be performed in a laminated state.

[0091] In a circular polarizer that has a polarizer and an oriented liquid crystal layer stacked together, it is preferable that the liquid crystal molecules in at least one oriented liquid crystal layer are aligned in parallel. In the circular polarizer, the orientation direction of the liquid crystal molecules in the oriented liquid crystal layer with parallel liquid crystal alignment is arranged in a manner that is neither parallel nor orthogonal to the absorption axis direction of the polarizer.

[0092] For example, when the circular polarizer has only one oriented liquid crystal layer, the oriented liquid crystal layer 1 is a 1 / 4 wavelength plate, and the angle between the absorption axis of the polarizer and the orientation direction of the liquid crystal molecules (generally the hysteresis axis) is set to 45°. The angle between the absorption axis of the polarizer and the orientation direction of the liquid crystal molecules can be 35-55°, 40-50°, or 43-47°.

[0093] In a configuration where the polarizer 4 and the aligned liquid crystal layer 1, which serves as a quarter-wavelength plate, are stacked at a 45° angle between their optical axes, an aligned liquid crystal layer 5 with liquid crystal molecules vertically aligned with the substrate surface can be included as an optical layer. By sequentially stacking the aligned liquid crystal layer 1, which serves as a quarter-wavelength plate, and the vertically aligned liquid crystal layer 5, which functions as a positive C-plate, on the polarizer, a circular polarizer that can block reflected light even from external light coming from an inclined direction can be formed. A vertically aligned liquid crystal layer (positive C-plate) and a parallel aligned liquid crystal layer (a quarter-wavelength plate serving as a positive A-plate) can be sequentially stacked on the polarizer.

[0094] like Figure 5 As shown, in a circular polarizer consisting of a polarizer 4 as an optical layer and multiple aligned liquid crystal layers 1 and 5 stacked together, both aligned liquid crystal layers 1 and 5 can be parallel aligned liquid crystal layers. In this case, it is preferable that the aligned liquid crystal layer 1 disposed near the polarizer 4 is a half-wavelength layer, and the aligned liquid crystal layer 5 disposed away from the polarizer is a quarter-wavelength layer. In this stacked configuration, it is preferable that the angle between the hysteresis axis direction of the half-wavelength layer and the absorption axis direction of the polarizer is 75°±5°, and the angle between the hysteresis axis direction of the quarter-wavelength layer and the absorption axis direction of the polarizer is 15°±5°. This stacked circular polarizer functions as a circular polarizer over a wide wavelength range of visible light, thus reducing chromatic aberration in reflected light.

[0095] [Image display device]

[0096] Figure 6 is a cross-sectional view showing a stacked configuration example of an image display device, and an alignment liquid crystal film having an alignment liquid crystal layer 1 is attached to the surface of an image display unit 50 via an adhesive layer 2. The alignment liquid crystal film can have two or more alignment liquid crystal layers. As the image display unit 50, a liquid crystal cell, an organic EL cell, or the like can be exemplified.

[0097] As described above, by performing the surface treatment of contacting the surface of the alignment liquid crystal layer with the organic solvent, the heat durability of the alignment liquid crystal layer is improved. The image display device having the alignment liquid crystal layer subjected to the surface treatment is excellent in heat durability because the change in retardation of the alignment liquid crystal layer is small even when exposed to a heated environment for a long time, and thus the change in visibility is small.

[0098] [Examples]

[0099] The present application is further explained by citing examples of production of the alignment liquid crystal film below, but the present application is not limited to the examples described below.

[0100] [Production of the alignment liquid crystal film]

[0101] <Comparative Example 1>

[0102] A photopolymerizable liquid crystal compound (Paliocolor LC242 manufactured by BASF) showing a nematic liquid crystal phase was dissolved in cyclopentanone to prepare a solution having a solid content concentration of 30% by weight. A surfactant (BYK-360 manufactured by BYK-Chemie) and a photopolymerization initiator (Omnirad 907 manufactured by IGM Resins) were added to the solution to prepare a liquid crystalline composition solution. The amounts of the leveling agent and the polymerization initiator were set to 0.01 parts by weight and 3 parts by weight, respectively, with respect to 100 parts by weight of the photopolymerizable liquid crystal compound.

[0103] A biaxially stretched norbornene-based film (Zeoron Film manufactured by Zeon, Japan, thickness: 33 μm, in-plane retardation: 135 nm) was used as a film substrate. The above liquid crystalline composition was applied to the surface of the film substrate in such a manner that the dried thickness becomes 1 μm using a bar coater, and the liquid crystal was aligned by heating at 100°C for 3 minutes. After cooling to room temperature, photopolymerization was performed by irradiation of ultraviolet rays having a cumulative light quantity of 400 mJ / cm 2 to obtain a laminate in which a parallel alignment liquid crystal layer was formed on the film substrate.

[0104] <Example 1>

[0105] After coating cyclopentanone on the surface of the oriented liquid crystal layer of the laminate of Comparative Example 1 using a wire bar (#10), the solvent was removed by heating at 110°C for 1 minute.

[0106] Examples 2 and 3

[0107] The heating temperature at the time of solvent removal was changed as shown in Table 1, and otherwise, the treatment was performed in the same manner as in Example 1 using cyclopentanone.

[0108] Example 4

[0109] A cyclopentanone solution (resin content: 3% by weight) of an acrylic resin (Nippon Shokubai Co., Ltd., copolymer of methyl methacrylate and butyl methacrylate, weight average molecular weight: 200,000) was prepared as a surface treatment liquid. After coating the surface treatment liquid on the surface of the oriented liquid crystal layer of the laminate of Comparative Example 1 using a wire bar (#10), the solvent was removed by heating at 85°C.

[0110] [Production of polarizing plate (circularly polarizing plate) having oriented liquid crystal layer]

[0111] A laminate (single-protected polarizing plate) in which a PVA-based polarizer having a thickness of 5 μm was provided on one side of an unstretched norbornene-based film (Zeonor Film" manufactured by Japan Synthetic Rubber Co., Ltd.) having a thickness of 20 μm via a UV (Ultraviolet)-curable adhesive was prepared.

[0112] A UV-curable adhesive composition was prepared by mixing 62 parts by weight of hydroxyethyl acrylamide ("HEAA" manufactured by Shin-Nakamura Chemical Co., Ltd.), 25 parts by weight of acryloylmorpholine ("ACMO" manufactured by Shin-Nakamura Chemical Co., Ltd.), 7 parts by weight of PEG (Polyethylene Glycol) 400# diacrylate ("Light acrylate 9EG-A" manufactured by Kyoeisha Chemical Co., Ltd.), and 3 parts by weight of a photopolymerization initiator ("Omnirad 907" manufactured by IGM Resins), and 3 parts by weight of 2,4-diethylthioxanthone ("Kayacure DETX-S" manufactured by Nippon Kayaku Co., Ltd.). About 1 μm-thick coating of the adhesive was applied on the surface of the above single-protected polarizing plate, and after the face of the oriented liquid crystal layer side of the laminate of the examples and comparative examples was attached to the coated layer of the adhesive, the adhesive was cured by irradiation of ultraviolet rays having a cumulative light amount of 1000 mJ / cm 2 at the time of attachment, the angle formed by the absorption axis direction of the polarizer and the orientation direction of the liquid crystal molecules in the oriented liquid crystal layer (the direction of the slow axis of the film substrate) was 45°.

[0113] The film substrate was peeled from the oriented liquid crystal film, an acrylic adhesive sheet having a thickness of 15 μm was attached to the surface of the oriented liquid crystal film, and the oriented liquid crystal layer was attached to the polarizer of the single-protected polarizing plate via the UV-curable adhesive layer to obtain a polarizing plate on which the acrylic adhesive sheet was provided.

[0114] [Assessment]

[0115] An evaluation sample was produced by attaching the adhesive layer of the above-described polarizing plate to a glass plate. After the in-plane retardation at a wavelength of 590 nm was measured using a phase difference meter ("KOBRA 21-ADH" manufactured by Oji Scientific Instruments), the evaluation sample was left in an air-circulating constant-temperature oven at 85°C for 120 hours. After the sample was taken out of the oven, the in-plane retardation was measured again, and the change rate of the retardation before and after the heating test was calculated.

[0116] The surface treatment conditions (type of treatment liquid and heating temperature) of the oriented liquid crystal layer of each of the above-described examples and comparative examples and the change rate of the in-plane retardation Re before and after the heating test are shown in Table 1.

[0117] [Table 1]

[0118]

[0119] In Comparative Example 1 in which no surface treatment of the oriented liquid crystal layer was performed, the amount of change in Re before and after the heating test was 3%, whereas in Examples 1 to 3 in which treatment was performed using cyclopentanone, the change rate of Re was reduced as compared with Comparative Example 1, and excellent heat resistance was exhibited. In Example 4 in which a treatment liquid containing a resin was used, the change in Re before and after the heating test was also suppressed as in Examples 1 to 3.

[0120] [Explanation of Reference Numerals]

[0121] 1: Oriented liquid crystal layer

[0122] 8: Support substrate

[0123] 4: Optical layer (polarizing plate)

[0124] 5: Optical layer (oriented liquid crystal layer)

[0125] 3, 7: Adhesive layer

[0126] 2: Adhesive layer

[0127] 9: Spacer

[0128] 50: Image display unit

Claims

1. A method for producing an oriented liquid crystal film, which is a method for producing an oriented liquid crystal film provided with an oriented liquid crystal layer in which liquid crystal molecules are parallel-aligned, the method comprising: a coating step of coating a liquid crystalline composition containing a photopolymerizable liquid crystal monomer on a support substrate; an alignment step of parallel-aligning the liquid crystal monomers in a liquid crystal state by heating the liquid crystalline composition on the support substrate; and a photocuring step of polymerizing or crosslinking the liquid crystal monomers by light irradiation, wherein after the photocuring step, surface treatment is performed in which an organic solvent that is soluble to the photopolymerizable liquid crystal monomer and does not dissolve or hardly dissolves a photocured product of the photopolymerizable liquid crystal monomer is brought into contact with a surface of the oriented liquid crystal layer, and after the surface treatment, heating is performed at 40 to 150°C to remove the organic solvent from the surface of the oriented liquid crystal layer.

3. The method for producing an oriented liquid crystal film according to claim 1 or 2, further comprising a step of laminating the oriented liquid crystal layer after the surface treatment and an optical layer via an adhesive. The optical layer is a polarizer, a transparent film, or another oriented liquid crystal layer. The adhesive is an adhesive of a type that is cured by active energy rays. wherein The adhesive is an adhesive of a type that is cured by active energy rays.

2. The method of manufacturing an oriented liquid crystal film according to claim 1, wherein, The support substrate is a resin film. ​ 4. The method of manufacturing an oriented liquid crystal film according to claim 3, wherein, ​ 5. The method of manufacturing an oriented liquid crystal film according to claim 3, wherein, ​ 6. The method of manufacturing an oriented liquid crystal film according to claim 4, wherein, ​ 7. The method of producing an oriented liquid crystal film according to claim 1 or 2, wherein, ​

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