JP2020034622A - Aligned liquid crystal film and production method of the same, optical film with adhesive and production method of the same, and image display device - Google Patents

Abstract

To provide an aligned liquid crystal film that hardly causes rework failure when bonded to an image display cell or the like via an adhesive layer.SOLUTION: The aligned liquid crystal film comprises a liquid crystal layer in which liquid crystal molecules are aligned in a predetermined direction, and contains two or more compounds. The aligned liquid crystal film contains a polymer of at least one photopolymerizable liquid crystal compound. In the aligned liquid crystal film, a ratio of a horizontal load at a depth of 30 nm from the surface to a horizontal load at a depth of 15 nm from the surface is preferably within a predetermined range. The aligned liquid crystal film is obtained, for example, by applying a liquid crystalline composition comprising at least one photopolymerizable liquid crystal compound and other compounds on a film substrate, aligning the liquid crystal molecules in a predetermined direction, and then polymerizing or crosslinking the liquid crystalline compound.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oriented liquid crystal film in which liquid crystal molecules are oriented, a method for manufacturing the same, and an image display device including the oriented liquid crystal film. Furthermore, the present invention relates to an optical film with an adhesive having an adhesive layer on one surface of an oriented liquid crystal film, and a method for producing the same.

  As an optical film having functions such as optical compensation of a liquid crystal display device and prevention of external light reflection of an organic EL element, a liquid crystal film in which a liquid crystal compound is oriented in a predetermined direction (aligned liquid crystal film) is used. Since the oriented liquid crystal film has a large birefringence as compared with a stretched polymer film, it is advantageous for thinning and weight reduction.

  When a thermorotopic liquid crystal is used, a liquid crystalline composition (solution) is applied on a substrate, and the compound contained in the composition is heated so as to be in a liquid crystal state, and then cooled to fix the alignment. An oriented liquid crystal film is obtained. When the liquid crystal composition contains a liquid crystal compound having a photopolymerizability (liquid crystal monomer), the stability can be improved by polymerizing or crosslinking the liquid crystal monomer by light irradiation after cooling.

  The liquid crystal compound can align liquid crystal molecules in a predetermined direction by a shearing force when applied on a substrate or an alignment regulating force of an alignment film, etc., and an aligned liquid crystal film having various optical anisotropies can be obtained. Can be For example, a homeotropically aligned liquid crystal film in which liquid crystal molecules having positive refractive index anisotropy are aligned in a direction normal to the film surface (thickness direction) has a refractive index in the thickness direction which is the alignment direction of the liquid crystal molecules (excessive light). The refractive index (nz) is larger than the in-plane refractive index (ordinary refractive index) nx and ny, and can be used as a positive C plate having a refractive index anisotropy of nz> nx = ny.

  Since a substance which spontaneously homeotropically aligns is very limited, a substrate having a vertical alignment film is generally used in producing a homeotropically aligned liquid crystal film. Patent Document 1 discloses a composition comprising a side chain type liquid crystal polymer having a monomer unit containing a liquid crystal fragment side chain and a monomer unit containing a non-liquid crystal fragment side chain, and a composition containing a photopolymerizable liquid crystal monomer. Discloses that a homeotropic alignment liquid crystal film can be formed on a substrate having no vertical alignment film. Patent Document 1 describes that a non-liquid crystalline fragment side chain of a liquid crystal polymer is considered to have an action of promoting homeotropic alignment.

  An image display device can be obtained by laminating the oriented liquid crystal film together with an optical film such as a polarizing plate on the surface of the image display cell. In general, an adhesive is used for attaching the oriented liquid crystal film to the image display cell. When bonding an optical film to an image display cell via an adhesive, defects such as mixing of air bubbles and displacement of a bonding position may occur. Further, after bonding the optical film to the image display cell, a defect due to a defect or the like of the optical film may be detected. When such a defect occurs, an operation (rework) of peeling the optical film from the image display cell is performed.

Patent No. 4174192

  The image display device is required to have higher durability, and the optical film does not peel from the image display cell even under severe conditions such as long-term exposure to a high-temperature and high-humidity environment and a drop impact test. Is required. By using an adhesive having a high adhesive strength for bonding the image display cell and the optical film, peeling of the optical film from the image display cell in an environment in which the image display device is used can be suppressed.

  On the other hand, if an adhesive having a high adhesive strength is used, a large peeling force is required during rework, and the adhesive remains on the surface of the image display cell (adhesive residue) or peels between layers of the optical film (interlayer peeling). ) May occur (rework failure). In particular, when the optical film contains an oriented liquid crystal film, a large peeling force at the time of rework, the cohesive failure of the oriented liquid crystal film is likely to occur, and the rework failure due to adhesive residue or delamination is likely to occur with this. It has been found by study of the present inventors.

  In view of the above, an object of the present invention is to provide an oriented liquid crystal film in which occurrence of rework failure is suppressed when the image display cell is bonded to the image display cell via an adhesive.

  In view of the above, as a result of the study by the present inventors, when the ratio of the horizontal load at a predetermined depth from the surface is within a predetermined range, the cohesive failure of the oriented liquid crystal film is unlikely to occur, and the image display cell via the adhesive. The present inventors have found that rework defects can be suppressed when they are bonded to each other.

  The present invention relates to an oriented liquid crystal film comprising a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction, and a method for manufacturing the same. The oriented liquid crystal film contains two or more compounds, at least one of which is a polymer of a photopolymerizable liquid crystal compound.

  Examples of other compounds contained in the oriented liquid crystal film include polymers. Examples of the polymer include a side chain type liquid crystal polymer. For example, a side-chain liquid crystal polymer in which an oriented liquid crystal film has a monomer unit containing a liquid crystal fragment side chain and a monomer unit containing a non-liquid crystal fragment side chain in addition to a polymer of a photopolymerizable liquid crystal compound. By containing, the homeotropic alignment of the photopolymerizable liquid crystal compound is promoted, and a homeotropically aligned liquid crystal film is obtained.

  An oriented liquid crystal film containing a polymer of a photopolymerizable liquid crystal compound is, for example, a liquid crystal containing a photopolymerizable liquid crystal compound and a compound having no photopolymerizability (for example, the above-mentioned side chain liquid crystal polymer) on a film substrate. It is obtained by applying a hydrophilic composition, heating the liquid crystalline composition to orient the liquid crystal molecules in a predetermined direction, and polymerizing or crosslinking the photopolymerizable liquid crystal compound by light irradiation. A film without an alignment film may be used as the film substrate. The film substrate provided with no alignment film may be a stretched film having an in-plane retardation of 10 to 500 nm.

Alignment liquid crystal film has a maximum horizontal load _{F 30} at a depth 30nm from the surface is preferably 1 to 2.2 times the maximum horizontal load _{F 15} at a depth 15nm from the surface. For example, F ₃₀ / F ₁₅ of the oriented liquid crystal film can be adjusted by adjusting the amount of light irradiation when polymerizing or crosslinking the photopolymerizable liquid crystal compound. The integrated irradiation light amount at the time of polymerizing or crosslinking the photopolymerizable liquid crystal compound is preferably from 100 to 370 mJ / cm ² .

  As an application form of the above-mentioned oriented liquid crystal film, an optical film with an adhesive having an adhesive layer on one main surface of the oriented liquid crystal film may be mentioned. The optical film with a pressure-sensitive adhesive may include another film bonded to the other main surface of the oriented liquid crystal film via an adhesive layer.

  An optical film with an adhesive comprising an adhesive layer on one side of the oriented liquid crystal film and another film bonded to the other side via an adhesive layer, for example, forms an oriented liquid crystal film on a film substrate Then, after laminating another film on the oriented liquid crystal film via an adhesive layer, the film substrate is peeled off, and an adhesive layer is laminated on the oriented liquid crystal film. The adhesive for bonding the oriented liquid crystal film to another film may be a photo-curable adhesive.

  The oriented liquid crystal film of the present invention hardly causes cohesive failure when performing rework after bonding to an image display cell via an adhesive, and is excellent in reworkability.

It is sectional drawing which shows one form of the optical film with an adhesive. It is a conceptual diagram which shows an example of the manufacturing process of the optical film with an adhesive. It is sectional drawing which shows the example of a lamination structure of an image display apparatus. 4 is a graph showing the relationship between the integrated light amount and the horizontal load when producing an oriented liquid crystal film of an example. It is a TEM cross-sectional observation image of the alignment liquid crystal film of an example.

  The oriented liquid crystal film of the present invention comprises a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction. The liquid crystal layer contains two or more compounds, at least one of which is a polymer of a photopolymerizable liquid crystal compound.

Alignment liquid crystal film of the present invention, horizontal load _{F 30} at a depth 30nm from the surface, which is 1 to 2.2 times the horizontal load _{F 15} at a depth 15nm from the surface. The horizontal load is a load when the nanoindentator is pushed to a predetermined depth and the sample is relatively moved in a horizontal direction (a direction orthogonal to the depth direction). The horizontal load is an index indicating the hardness of the sample at a predetermined depth. The fact that the horizontal load varies depending on the indentation depth means that the sample has a hardness distribution in the depth direction.

In the oriented liquid crystal film of the present invention, F ₃₀ / F ₁₅ is 2.2 or less, and the hardness distribution in the depth direction near the surface is small. Therefore, when the oriented liquid crystal film is bonded to the image display cell using the adhesive, when performing rework, cohesive failure of the oriented liquid crystal film is unlikely to occur, and defects such as adhesive residue on the image display cell (defective rework). Can be suppressed.

  FIG. 1 is a cross-sectional view showing one embodiment of an optical film with an adhesive in which an adhesive layer 2 is attached to an oriented liquid crystal film 1. The optical film with a pressure-sensitive adhesive of FIG. 1 includes a pressure-sensitive adhesive layer 2 on one main surface of an oriented liquid crystal film 1 and a film 4 bonded on the other surface via an adhesive layer 3. A separator 9 is temporarily attached to the surface of the pressure-sensitive adhesive layer 2.

  2A to 2D show an example of a manufacturing process of an optical film with a pressure-sensitive adhesive. First, a liquid crystal composition containing a liquid crystal compound is applied on the film substrate 8, and photopolymerization is performed in a state where the liquid crystal molecules are aligned in a predetermined direction to fix the alignment state of the liquid crystal molecules. A laminate 10 provided with the oriented liquid crystal film 1 is obtained (FIG. 2A). In this laminate 10, the surface of the oriented liquid crystal film 1 that is in contact with the film substrate 8 is referred to as a “substrate surface”, and the opposite surface is referred to as an “air surface”.

  The film 4 is bonded to the air surface 12 of the oriented liquid crystal film 1 via the adhesive layer 3 (FIG. 2B), and the film substrate 8 is peeled from the substrate surface 11 of the oriented liquid crystal film 1 (FIG. 2C). By laminating the pressure-sensitive adhesive layer 2 on the substrate surface 11 of the oriented liquid crystal film 1 (FIG. 2D), an optical film with a pressure-sensitive adhesive having the pressure-sensitive adhesive layer 2 on the substrate surface 11 of the oriented liquid crystal film 1 is obtained.

  The optical film with an adhesive is used, for example, for forming an image display device. FIG. 3 is a cross-sectional view illustrating an example of a layered configuration of an image display device including an optical film with an adhesive, in which an oriented liquid crystal film 1 is attached to the surface of an image display cell 50 via an adhesive layer 2. . Examples of the image display cell 50 include a liquid crystal cell and an organic EL cell.

[Oriented liquid crystal film]
The oriented liquid crystal film is composed of a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction and the orientation state is fixed. Since the oriented liquid crystal film has much larger birefringence than a film made of a non-liquid crystal material, the thickness of an optically anisotropic element having a desired retardation can be made much smaller. The thickness of the oriented liquid crystal film is about 0.5 to 7 μm, and preferably 1 to 5 μm.

  The liquid crystal layer contains two or more compounds, at least one of which is a polymer of a photopolymerizable liquid crystal compound. The oriented liquid crystal film is obtained by applying a liquid crystalline composition on a film substrate, heating the liquid crystalline composition to orient the liquid crystal molecules in a predetermined direction, and polymerizing or crosslinking the liquid crystalline compound by light irradiation. .

<Liquid crystal composition>
The liquid crystal composition contains two or more compounds. The liquid crystal composition contains at least one photopolymerizable liquid crystal compound. The liquid crystal compound contained in the liquid crystal composition preferably has a liquid crystal phase of a nematic phase (nematic liquid crystal). The mechanism for developing the liquid crystal properties of the liquid crystal compound may be either lyotropic or thermotropic. In order to obtain a homeotropically aligned liquid crystal film, it is preferable to use a thermotropic liquid crystal.

(Photopolymerizable liquid crystal compound)
The photopolymerizable liquid crystal compound (monomer) has a mesogen 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 from 40 to 100C, more preferably from 50 to 90C, even more preferably from 55 to 85C.

  In the production of an oriented liquid crystal film, a liquid crystalline composition is coated on a substrate, heated above the liquid crystal phase transition temperature to orient the liquid crystal molecules, then cooled below the glass transition temperature to fix the orientation, To perform photocuring (polymerization and / or crosslinking) of the liquid crystal monomer. By the light irradiation, the photopolymerizable functional group of the liquid crystal monomer reacts to obtain a polymer of the photopolymerizable liquid crystal compound. The polymer after photo-curing is non-liquid crystalline and does not undergo transition of a liquid crystal phase, a glass phase, or a crystal phase due to a change in temperature. Therefore, when photocuring is performed in a state where the liquid crystal monomer is oriented in a predetermined direction, an oriented liquid crystal film which is hardly affected by a temperature change and has excellent stability is obtained.

  As the mesogen group of the liquid crystal monomer, biphenyl group, phenylbenzoate group, phenylcyclohexane group, azoxybenzene group, azomethine group, azobenzene group, phenylpyrimidine group, diphenylacetylene group, diphenylbenzoate group, bicyclohexane group, cyclohexylbenzene group, And a cyclic structure such as a terphenyl group. The terminal of these cyclic units may have a substituent such as a cyano group, an alkyl group, an alkoxy group, and a halogen group.

  Examples of the photopolymerizable functional group include a (meth) acryloyl group, an epoxy group, and a vinyl ether group. Among them, a (meth) acryloyl group is preferable. The photopolymerizable liquid crystal monomer preferably has 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 photopolymerization, and the durability of the oriented liquid crystal film tends to be improved.

  Any appropriate liquid crystal monomer can be adopted as the liquid crystal monomer. For example, WO 00/37585, US Pat. No. 5,211,877, US Pat. No. 4,388,453, WO 93/22397, European Patent No. 0261712, German Patent No. 19504224, German Patent No. 4408171, Polymerizable mesogenic compounds described in British Patent No. 2280445 and the like can be used. Specific examples of the liquid crystal monomer include “Paliocolor LC242” manufactured by BASF, “E7” manufactured by Merck, and “LC-Silicon-CC3767” manufactured by Wacker-Chem.

  Examples of the photopolymerizable liquid crystal monomer having a mesogen group and a plurality of (meth) acryloyl groups in one molecule include a compound represented by the following general formula (IV).

  In the formula (IV), R is a hydrogen atom or a methyl group, A and D are each independently a 1,4-phenylene group or a 1,4-cyclohexylene group, and B is a 1,4-phenylene group, , 4-cyclohexylene group, 4,4'-biphenylene group or 4,4'-bicyclohexylene group, and Y and Z are each independently -COO-, -OCO- or -O-. g and h are each independently an integer of 2 to 6.

(Liquid crystal polymer)
The liquid crystal composition preferably contains, in addition to the liquid crystal monomer, a compound that controls the alignment of the liquid crystal monomer in a predetermined direction. When the liquid crystal composition contains a compound that controls the alignment of liquid crystal monomers, a liquid crystal layer in which liquid crystal molecules are aligned in a predetermined direction can be formed even when a substrate having no alignment film is used.

  The compound for controlling the alignment of the liquid crystal monomer may be a polymer or a low molecular weight compound. For example, in order for the liquid crystal monomer to be homeotropically aligned, the liquid crystal composition preferably contains a side chain type liquid crystal polymer.

  The side chain type liquid crystal polymer may be a homopolymer or a copolymer. The side chain type liquid crystal polymer may include only a monomer unit having a liquid crystal fragment side chain, and in addition to a monomer unit having a liquid crystal fragment side chain, a monomer unit having no liquid crystal fragment in the side chain. May be included. Examples of the monomer unit having no liquid crystal fragment in the side chain include a monomer unit having no side chain and a monomer unit having a non-liquid crystal fragment in the side chain.

  When the polymer has a liquid crystal fragment in a side chain, liquid crystallinity is expressed, and when the liquid crystal composition is heated to a predetermined temperature, the polymer tends to be oriented in a predetermined direction. When the polymer has a non-liquid crystalline fragment in a side chain, an alignment force for homeotropically aligning the photopolymerizable liquid crystal monomer contained in the liquid crystalline composition together with the polymer acts. By aligning the liquid crystal monomer along with the alignment of the side chain type liquid crystal polymer and fixing this alignment state, a homeotropic alignment liquid crystal film can be obtained.

  Examples of the monomer having a liquid crystal fragment side chain include a polymerizable compound having a nematic liquid crystal substituent having a mesogen group. Examples of the mesogen group include those exemplified above as the mesogen group of the liquid crystal monomer. Especially, what has a biphenyl group or a phenyl benzoate group as a mesogen group is preferable.

  Examples of the monomer having a non-liquid crystalline fragment side chain include a polymerizable compound having a linear substituent such as a long-chain alkyl having 7 or more carbon atoms. Examples of the polymerizable functional group of the liquid crystal monomer and the non-liquid crystal monomer include a (meth) acryloyl group.

  As the side chain type liquid crystal polymer, a copolymer having a liquid crystal monomer unit represented by the general formula (I) and a non-liquid crystal monomer unit represented by the general formula (II) is preferably used.

In the formula (I), R ¹ is a hydrogen atom or a methyl group, R ² is a cyano group, a fluoro group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and X ¹ it is -CO ₂ - is or -OCO-. a is an integer of 1 to 6, and b and c are each independently 1 or 2.

In the formula (II), R ³ is a hydrogen atom or a methyl group, and R ⁴ is represented by an alkyl group having 7 to 22 carbon atoms, a fluoroalkyl group having 1 to 22 carbon atoms, or the following general formula (III) Group.

In the formula (III), R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, and d is an integer of 1 to 6.

  The ratio of the liquid crystal monomer unit to the non-liquid crystal monomer unit in the side chain liquid crystal polymer is not particularly limited, but when the ratio of the non liquid crystal monomer unit is small, the photopolymerizable liquid crystal compound accompanying the alignment of the side chain liquid crystal polymer is used. May be insufficient, and the orientation of the liquid crystal layer after photo-curing may be non-uniform. On the other hand, when the proportion of the liquid crystalline monomer unit is small, the side chain type liquid crystal polymer is less likely to exhibit liquid crystal monodomain alignment. Therefore, the molar ratio of the non-liquid crystalline monomer to the total of the liquid crystalline monomer unit and the non-liquid crystalline monomer unit is preferably 0.01 to 0.8, more preferably 0.1 to 0.6, and more preferably 0.15 to 0.6. ~ 0.5 is more preferred. The weight average molecular weight of the side chain type liquid crystal polymer is preferably about 2,000 to 100,000, and more preferably about 2,500 to 50,000, from the viewpoint of achieving both the film formability and the orientation of the liquid crystalline composition.

  The side chain type liquid crystal polymer can be polymerized by various known methods. For example, when the monomer unit has a (meth) acryloyl group as a polymerizable functional group, a side chain type liquid crystal polymer having a liquid crystal fragment and a non-liquid crystal fragment can be obtained by radical polymerization using light or heat.

(composition)
The ratio of the photopolymerizable liquid crystal compound (monomer) to the other compound in the liquid crystal composition is not particularly limited. From the viewpoint of obtaining a highly durable oriented liquid crystal film, the content of the photopolymerizable liquid crystal compound is preferably larger than the contents of other compounds. In the liquid crystalline composition containing the photopolymerizable liquid crystal compound and the liquid crystal polymer, the content (weight) of the photopolymerizable liquid crystal compound is determined from the viewpoint of obtaining a highly oriented liquid crystal film having high durability and uniform alignment. Is preferably 1.5 to 15 times, more preferably 2 to 10 times, even more preferably 2.5 to 6 times the content of

  In order to promote the curing of the photopolymerizable liquid crystal compound by light irradiation, the liquid crystalline composition preferably contains a photopolymerization initiator. As the photopolymerization initiator, those which generate radicals by light irradiation (photoradical generator) are preferable. The content of the photopolymerization initiator in the liquid crystalline composition is usually about 0.5 to 20 parts by weight, preferably about 3 to 15 parts by weight, more preferably about 100 parts by weight of the photopolymerizable liquid crystal compound. Is about 5 to 10 parts by weight.

  A liquid crystal composition can be prepared by mixing a photopolymerizable liquid crystal compound, another compound (for example, a side chain type liquid crystal polymer), and a photopolymerization initiator with a solvent. The solvent is not particularly limited as long as it can dissolve the photopolymerizable liquid crystal compound and does not erode (or has low erosion) the film substrate. Chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene Halogenated hydrocarbons such as tetrachloroethylene, chlorobenzene and orthodichlorobenzene; phenols such as phenol and valachlorophenol; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene and 1,2-dimethoxybenzene; acetone; Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone and N-methyl-2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol; Alcohol solvents such as Lyserine, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide A nitrile solvent such as acetonitrile and butyronitrile; an ether solvent such as diethyl ether, dibutyl ether and tetrahydrofuran; and ethylcellosolve and butylcellosolve. The concentration of the liquid crystal composition is usually about 3 to 50% by weight, preferably about 7 to 35% by weight.

<Film substrate>
As a substrate on which the liquid crystalline composition is applied, a film substrate is preferably used. By using a film substrate, a series of steps from the application of the liquid crystalline composition on the substrate to the curing by photopolymerization of the liquid crystal monomer can be performed by roll-to-roll, so that the productivity of the oriented liquid crystal film can be improved. .

  The film substrate has a first main surface and a second main surface, and the liquid crystal composition is applied on the first main surface. The resin material constituting the film substrate is not particularly limited as long as it does not dissolve in the solvent of the liquid crystal composition and has heat resistance at the time of heating for orienting the liquid crystal composition, polyethylene terephthalate, polyethylene Polyesters such as naphthalate; polyolefins such as polyethylene and polypropylene; cyclic polyolefins such as norbornene polymers; cellulose polymers such as diacetylcellulose and triacetylcellulose; acrylic polymers; styrene polymers; polycarbonates, polyamides, polyimides and the like. . Among them, it is particularly preferable to use a norbornene-based polymer film as the film substrate, since a film having excellent fluidity during molding and having high smoothness is easily obtained. Norbornene-based polymer films are also preferred because they have excellent releasability when transferring an oriented liquid crystal film to another film or the like. Examples of the norbornene-based polymer include ZEONOR and ZEONEX manufactured by Zeon Corporation and ARTON manufactured by JSR.

  An orientation film may be provided on the film substrate. The alignment film may be appropriately selected depending on the type of the liquid crystal compound, the material of the substrate, and the like. Examples of an aligning agent for forming an alignment film include lecithin, stearic acid, hexadecyltrimethylammonium bromide, octadecylamine hydrochloride, a monobasic chromium carboxylate complex, an organic silane such as a silane coupling agent and a siloxane compound, and perfluorosilane. Examples include dimethylcyclohexane, tetrafluoroethylene, polytetrafluoroethylene, and the like.

  As described above, in addition to the photopolymerizable liquid crystal compound, if the liquid crystal composition contains a compound that promotes the alignment of the liquid crystal in a predetermined direction, even when a substrate without an alignment film is used. And a homeotropically aligned liquid crystal film can be formed. By eliminating the need for an alignment film, the versatility of the film substrate can be increased, the process can be simplified, and the manufacturing cost can be reduced.

  A stretched film may be used as the film substrate. By stretching the film, unevenness such as a die line during film formation is leveled, so that the smoothness of the film substrate is improved, and the arithmetic average roughness Ra tends to be reduced. It is particularly preferable to use a biaxially stretched film as the film substrate because of high surface uniformity.

The in-plane retardation _R0 of a stretched film used as a film substrate is generally 10 nm or more. When the film substrate is a stretched film having an in-plane retardation of 10 nm or more, the polymer constituting the film is preferentially oriented in a predetermined direction (slow axis direction or fast axis direction). Since the alignment of the polymer on the film substrate has an alignment regulating force for homogeneously aligning the liquid crystal molecules, when no vertical alignment film is provided, the homeotropic alignment of the liquid crystal molecules may be inhibited, and an alignment defect may occur. As will be described in detail later, by lowering the heating temperature when the liquid crystal molecules are homeotropically aligned, a homeotropically aligned liquid crystal film with few alignment defects can be obtained even when a stretched film substrate is used.

If the in-plane retardation of the film substrate is excessively large, the temperature range in which alignment defects can be reduced becomes narrow, and liquid crystal phase transition within the temperature range may become difficult. Therefore, the in-plane retardation _R0 of the film substrate is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less.

The thickness of the film substrate is not particularly limited, but is usually about 10 to 200 μm in consideration of handling properties and the like. The in-plane birefringence Δn (value obtained by dividing the in-plane retardation R ₀ by the thickness) of the stretched film is preferably 0.01 or less, more preferably 0.008 or less, and even more preferably 0.006 or less.

  The arithmetic average roughness Ra of the first main surface of the film substrate is preferably 3 nm or less, more preferably 2 nm or less, and even more preferably 1.5 nm or less. By applying the liquid crystalline composition to a film substrate surface having a small Ra and a high smoothness, the alignment defects of the aligned liquid crystal film tend to be reduced. As described above, stretching the film tends to reduce the Ra of the film. Therefore, the use of a stretched film substrate tends to reduce alignment defects of the alignment liquid crystal fill.

  Since the surface shape of the first principal surface of the film substrate is transferred to the oriented liquid crystal film formed thereon, Ra of the substrate surface of the oriented liquid crystal film is substantially equal to Ra of the first principal surface of the substrate. Therefore, when a film substrate having a first principal surface having a Ra of 3 nm or less is used, the Ra of the substrate surface of the oriented liquid crystal film is often 3 nm or less. In addition, Ra on the air surface during application of the liquid crystalline composition tends to be smaller than Ra on the substrate surface. Therefore, when a film substrate having a first main surface having a Ra of 3 nm or less is used, the arithmetic average roughness of both surfaces of the oriented liquid crystal film is often 3 nm or less.

  In order to keep the arithmetic average roughness within the above range, the film substrate preferably does not contain a filler inside. A film that does not contain a filler and has a high surface smoothness has a low slipperiness, and thus may cause blocking or poor transport or poor winding in a roll-to-roll process. In order to prevent blocking or poor transport due to high smoothness, a method of attaching another film having high slipperiness to a film substrate, or a method of providing a film substrate with a slippery layer are exemplified. In the case where another film is bonded to the film substrate, defects (such as poor liquid crystal alignment and optical defects) caused by transfer of the adhesive layer to the first principal surface (the surface to which the liquid crystalline composition is applied) are suppressed. From the viewpoint of performing, it is preferable to bond the second main surface (the surface opposite to the surface on which the liquid crystalline composition is applied). However, in the roll-to-roll process, when the film substrate is wound, an adhesive or the like attached to the second main surface may be transferred to the first main surface, causing poor alignment or optical defects.

  Therefore, it is preferable to improve the slipperiness by providing a slippery layer on at least one surface of the film substrate. Examples of the slippery layer include a layer in which a fine filler having an average particle size of 100 nm or less is contained in a binder such as polyester or polyurethane.

  When the oriented liquid crystal film 1 is bonded to the film 4 and then peeled off from the film substrate 8 (see FIGS. 2B and 2C), the releasability is maintained and the oriented liquid crystal film 1 is peeled off from the film substrate 8. From the viewpoint of suppressing problems such as the transfer of the slippery layer to the film substrate 8, the film substrate 8 preferably does not have the slippery layer on the surface to which the liquid crystalline composition is applied. That is, it is preferable to use a film substrate that has a slippery layer on the second main surface and does not have a slippery layer on the first main surface.

<Formation of oriented liquid crystal film on film substrate>
A liquid crystal composition is applied on a film substrate, and the liquid crystal compound is oriented in a liquid crystal state by heating, and then cooled to fix the orientation, and the photopolymerizable liquid crystal compound is polymerized or cross-linked by light irradiation, whereby the alignment is performed. A liquid crystal film is obtained.

  The method of applying the liquid crystalline composition on the film substrate is not particularly limited, and employs spin coating, Daiko, kiss roll coating, gravure coating, reverse coating, spray coating, Meyer bar coating, knife roll coating, air knife coating, etc. it can. After applying the solution, the solvent is removed to form a liquid crystal composition layer on the film substrate. The coating thickness is preferably adjusted so that the thickness of the liquid crystal composition layer after drying the solvent (the thickness of the oriented liquid crystal film) is about 0.5 to 7 μm.

  By heating the liquid crystalline composition layer formed on the film substrate into a liquid crystal phase, the liquid crystal compound is oriented. The heating temperature is not particularly limited, but is usually about 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, alignment defects tend to increase. Therefore, the heating temperature is preferably from 45 to 100C, more preferably from 50 to 95C, and still more preferably from 55 to 90C. The heating time may be adjusted so that the transition to the liquid crystal phase is sufficient, and is usually about 30 seconds to 30 minutes.

When a stretched film substrate without an alignment film is used, the homogenous alignment regulating force due to the molecular alignment of the film substrate tends to increase with an increase in the heating temperature. When a homeotropic alignment liquid crystal film is prepared by applying a liquid crystal composition on a stretched film substrate on which an alignment film is not provided and using the liquid crystal composition, heating is performed at a low temperature within a temperature range in which a liquid crystal polymer transitions to a liquid crystal phase. Is preferred. The heating temperature T (° C.) at the time of orientation is preferably 100-3.5 × 10 ³ Δn or less. Δn is the in-plane birefringence of the stretched film substrate. The heating temperature T is more preferably 100-4 × 10 ³ Δn or less, and further preferably 100-4.5 × 10 ³ Δn or less. Further, the heating temperature T is preferably 100-0.1R ₀ or less, more preferably 100-0.12R ₀ or less, more preferably 100-0.13R ₀ or less. R ₀ is the in-plane retardation of the stretched film substrate.

As described above, by using a stretched film substrate having high smoothness, and by adjusting the heating temperature T when aligning the liquid crystal, even when using a substrate having no alignment film, the homeotropic alignment liquid crystal film Poor alignment can be suppressed. In the homeotropically aligned liquid crystal film, the number of light leakage (poor alignment) observed under a polarizing microscope is preferably 1 or less per cm ² , more preferably 0.7 or less, and 0.5 or less. It is more preferred that: The number of alignment defects is determined as an average value of observations at 10 locations in the film plane.

  After heating, the orientation is fixed by cooling to a temperature equal to or lower than the glass transition temperature. The cooling method is not particularly limited, and for example, it may be taken out of the heating atmosphere to room temperature. Forced cooling such as air cooling or water cooling may be performed.

  By irradiating the liquid crystal composition layer with the fixed orientation with light to polymerize or crosslink the photopolymerizable liquid crystal compound, the orientation of the photopolymerizable liquid crystal compound is fixed, and the durability of the oriented liquid crystal film is improved. As the light to be irradiated, light having a wavelength at which the photopolymerization initiator has sensitivity may be selected, and generally, ultraviolet light is used. As the ultraviolet light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an LED, a black light, a chemical lamp, and the like are used. In order to promote the photopolymerization reaction, light irradiation is preferably performed in an atmosphere of an inert gas such as nitrogen gas.

  When the photopolymerizable liquid crystal compound contains a non-photopolymerizable compound (for example, a polymer) in addition to the photopolymerizable liquid crystal compound, the photopolymerizable compound cures by irradiation with light. Thus, the compounds having no photopolymerizability do not react. If the compound having no photopolymerizability is unevenly distributed in the coating layer of the liquid crystal composition, a local difference occurs in the hardness of the oriented liquid crystal film as the photocuring reaction proceeds.

For example, when a liquid crystalline composition containing a photopolymerizable liquid crystal compound and a side chain type liquid crystal polymer is applied on the film substrate 8, the coating layer has a side chain type liquid crystal near the interface with the film substrate 8 and near the air interface. The liquid crystal polymer tends to be unevenly distributed. When the photocuring is performed in a state where the polymer is unevenly distributed in the vicinity of the interface as described above, the hardness of the central portion in the thickness direction of the liquid crystal layer (the region where the concentration of the photopolymerizable compound is high) increases with the progress of the photocuring. On the other hand, in the vicinity of the interface (a region where the concentration of the photopolymerizable compound is small and the concentration of the polymer is high), the change in hardness is small, so that the difference in hardness in the thickness direction (depth direction) is large. Accordingly, the ratio F ₃₀ / F ₁₅ of the horizontal load F ₁₅ at a depth of ₁₅ nm from the surface (interface) to the horizontal load F _{30 at} a depth of 30 nm tends to increase.

In order to set F ₃₀ / F ₁₅ to 2.2 or less, it is preferable to adjust the amount of light irradiation at the time of photocuring to suppress excessive progress of photocuring. As the light irradiation amount in the light-curing is large, the photocuring of the photopolymerizable liquid crystal compound progresses, tends to F _{30 /} F ₁₅ is increased.

Cumulative amount of light irradiated during photocuring is preferably 370mJ / cm ² or less, 350 mJ / cm ² or less being more preferred. On the other hand, when the light irradiation amount is excessively small, the curing of the photopolymerizable compound becomes insufficient, and the hardness and the heat durability of the oriented liquid crystal film tend to decrease. Therefore, the total irradiation light amount at the time of photocuring is preferably 100 mJ / cm ² or more, more preferably 130 mJ / cm ² or more, 150 mJ / cm ² or more is more preferable. The integrated irradiation light amount at the time of photocuring of the liquid crystal alignment film is the integrated light amount of UVA (wavelength 320 to 390 nm) measured using an integrating light amount meter.

As described above, F ₃₀ / F ₁₅ of the oriented liquid crystal film is preferably from 1 to 2.2. F ₃₀ / _{F 15} is more preferably 1.1 to 2.1, more preferably 1.2 to 2. When F ₃₀ / F ₁₅ is within the above range, the cohesive failure of the oriented liquid crystal film hardly occurs when performing rework after bonding the oriented liquid crystal film to the image display cell using an adhesive, thereby suppressing rework failure. it can. F ₃₀ / F ₁₅ may be 1.3 or more, 1.4 or more, or 1.5 or more. F ₃₀ / F ₁₅ may be 1.9 or less or 1.8 or less.

From the viewpoint of imparting sufficient hardness to alignment liquid crystal film, horizontal load _{F 15} at a depth 15nm from the surface is preferably at least 1MyuN, more preferably at least 2MyuN, and even more preferably 2.5MyuN. F ₁₅ may be of 3μN more or 3.5μN more. On the other hand, from the viewpoint of keeping F ₃₀ / F ₁₅ in an appropriate range, F ₁₅ is preferably equal to or less than 20 μN, more preferably equal to or less than ₁₅ μN, and still more preferably equal to or less than 10 μN. F ₁₅ is, 8MyuN following 6MyuN hereinafter, it may be not more than 5μN less or 4.5MyuN.

When the light irradiation amount during photocuring is large and the curing of the photopolymerizable compound proceeds, the horizontal load of the oriented liquid crystal film tends to increase. On the other hand, when the polymer is unevenly distributed near the interface, the change in the horizontal load near the interface is small even if the curing of the photopolymerizable compound proceeds. Therefore, F ₁₅ has a large influence of the properties of the polymer contained in the liquid crystal composition. Therefore, by selecting the structure and molecular weight of the polymer contained in the liquid crystal composition, the F ₁₅ of aligned liquid crystal film can be set in the above range.

Horizontal load _{F 30} at a depth 30nm from the surface of the aligned liquid crystal film is preferably at least 1.5MyuN, more preferably at least 2.5MyuN, and even more preferably 3MyuN. F ₃₀ is more 3.5MyuN, more 4MyuN, may be 4.5μN more or 5μN more. On the other hand, from the viewpoint of maintaining F ₃₀ / F ₁₅ in an appropriate range, F ₃₀ is preferably equal to or less than 40 μN, more preferably equal to or less than 25 μN, and still more preferably equal to or less than 15 μN. F ₃₀ is, 10MyuN hereinafter, it may be not more than 9μN less or 8MyuN.

Even if the polymer is unevenly distributed in the vicinity of the interface, in the vicinity of the depth 30nm from the surface, high concentration of the photopolymerizable compound, because the concentration of the polymer is low, F ₃₀ with the progress of curing of the photopolymerizable compound Tends to be large. Therefore, by adjusting the amount of light irradiation time of light curing, it is possible to adjust the F ₃₀ in a desired range.

[Uses of oriented liquid crystal film]
The oriented liquid crystal film can be used as an optical film for a display for the purpose of compensating for a viewing angle or the like. The oriented liquid crystal film may be used in a state of being laminated on a film substrate, or may be used after being separated from the film substrate. It is preferable that the oriented liquid crystal film 1 is bonded to another film 4 via the adhesive layer 3 as shown in FIG. 2C, and then the film substrate 8 is peeled off as shown in FIG. 2D. By laminating with the film 4 via the adhesive layer 3, a laminated optical film in which the oriented liquid crystal film is firmly adhered on the film 4 is obtained.

The optical characteristics of the oriented liquid crystal film are not particularly limited. The homeotropically-aligned liquid crystal film has an in-plane retardation of approximately 0 (for example, 5 nm or less, preferably 3 nm or less) and a negative retardation in the thickness direction (having a refractive index anisotropy of nz> nx = ny). It is a positive C plate. (Nx-nz) and the thickness is expressed by the product of the thickness direction retardation _{R t} homeotropic alignment liquid crystal film, for example, about -50 to-500 nm.

[Optical film with adhesive]
When the image display device is formed by laminating the oriented liquid crystal film 1 with the image display cell 50, it is preferable to use an optical film with an adhesive in which the adhesive layer 2 is previously laminated on the surface of the oriented liquid crystal film 1. The optical film with an adhesive may have an adhesive layer on either the substrate surface 11 or the air surface 12 of the oriented liquid crystal film 1.

<Adhesive layer>
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 2 is not particularly limited, and a material having an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based polymer, rubber-based polymer, or the like as a base polymer is appropriately selected. Can be used. In particular, an adhesive such as an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive that is excellent in transparency, exhibits appropriate wettability, cohesiveness, and adhesion, and is excellent in weather resistance, heat resistance, and the like is preferable. The thickness of the pressure-sensitive adhesive layer is appropriately set according to the type of the adherend and the like, and is generally about 5 to 500 μm.

  When an adhesive layer is provided on the air surface 12 of the oriented liquid crystal film 1, the adhesive layer may be laminated on the air surface 12 in a state where the oriented liquid crystal film 1 is provided on the film substrate 8 (see FIG. 2A). . When an adhesive layer is provided on the air surface 11 of the oriented liquid crystal film 1, the film substrate 8 is peeled off from the oriented liquid crystal film 1 to expose the substrate surface 11 of the oriented liquid crystal film 1. 2 may be laminated.

  The lamination of the pressure-sensitive adhesive layer 2 on the oriented liquid crystal film 1 is performed, for example, by bonding a pressure-sensitive adhesive previously formed in a sheet shape to the surface of the oriented liquid crystal film 1. After applying the pressure-sensitive adhesive composition on the oriented liquid crystal film 1, the pressure-sensitive adhesive layer 2 may be formed by performing drying, crosslinking, photocuring, or the like of the solvent. In order to increase the adhesive strength (anchoring force) between the oriented liquid crystal film 1 and the pressure-sensitive adhesive layer 2, the surface of the oriented liquid crystal film 1 is subjected to a surface treatment such as corona treatment, plasma treatment or the like, and the adhesive layer is formed. 2 may be laminated.

  Since the thickness of the oriented liquid crystal film 1 is small, it is difficult to say that the oriented liquid crystal film 1 alone has sufficient handling properties. Therefore, when the pressure-sensitive adhesive layer 2 is laminated on the substrate surface 11 of the oriented liquid crystal film 1, the adhesive layer 2 is provided on the film substrate 8 (FIG. 2A), and After bonding the film 4 (FIG. 2B), it is preferable to peel the film substrate 8 from the substrate surface 11 of the oriented liquid crystal film 1 (FIG. 2C). Since the oriented liquid crystal film 1 and the other film 4 are laminated, the thickness is larger and the handleability is improved as compared with the case where the oriented liquid crystal film 1 is used alone.

<Separator>
It is preferable that a separator 9 is temporarily attached to the surface of the pressure-sensitive adhesive layer 2. The separator 9 protects the surface of the pressure-sensitive adhesive layer 2 until the optical film with the pressure-sensitive adhesive is bonded to the image display cell 50. As a constituent material of the separator, a plastic film such as acryl, polyolefin, cyclic polyolefin, or polyester is preferably used. The thickness of the separator is usually about 5 to 200 μm. The surface of the separator is preferably subjected to a release treatment. Examples of the release agent include silicone-based materials, fluorine-based materials, long-chain alkyl-based materials, and fatty acid amide-based materials.

<Other films>
The film 4 to be bonded to the oriented liquid crystal film 1 is not particularly limited, and an optically isotropic or optically anisotropic film generally used as an optical film can be used without any particular limitation. The film 4 may be a single-layer film or a laminate of a plurality of films.

  Specific examples of the film 4 include a retardation film, a polarizer, and a polarizer protective film. The film 4 may be a functional film such as a viewing angle widening film, a viewing angle restriction (prevention of peeping) film, and a brightness enhancement film.

  For example, in a liquid crystal display device, an image display cell (liquid crystal cell) and a polarizer are used to appropriately change the polarization state of light emitted from the liquid crystal cell to the viewing side to improve viewing angle characteristics. In some cases, a retardation plate as an optical compensation film is disposed therebetween. In an organic EL display device, a 波長 wavelength plate may be disposed between a cell and a polarizing plate in order to suppress external light from being reflected by a metal electrode layer and visually recognized as a mirror surface. . Further, by disposing a quarter-wave plate on the viewing side of the polarizing plate and making the emitted light circularly polarized, a viewer wearing polarized sunglasses can visually recognize an appropriate image display. .

  The film 4 may have a predetermined function integrally with the oriented liquid crystal film 1. For example, when the alignment liquid crystal film 1 is a homeotropic alignment film (positive C plate) and the film 4 is a polarizing plate (circular polarizing plate) including a quarter-wave plate and a polarizer from the alignment liquid crystal film 1 side. By laminating the homeotropically-aligned liquid crystal film and the quarter-wave plate, it is possible to form a circularly polarizing plate capable of shielding reflected light even from external light in oblique directions. Such a circularly polarizing plate is used, for example, by being bonded to the surface of an organic EL cell.

<Adhesive>
It is preferable that the oriented liquid crystal film 1 and the film 4 are bonded via an appropriate adhesive layer 3. The material of the adhesive is not particularly limited as long as it is optically transparent, and examples thereof include an epoxy resin, a silicone resin, an acrylic resin, polyurethane, polyamide, polyether, and polyvinyl alcohol. 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 of using a curable adhesive exhibiting adhesiveness by a crosslinking reaction after application, the thickness of the adhesive layer 3 is preferably 0.01 to 5 μm, more preferably 0.03 to 3 μm.

  As the adhesive, various forms such as a water-based adhesive, a solvent-based adhesive, a hot-melt adhesive, and an active energy ray-curable adhesive are used. Among these, a water-based adhesive or an active energy ray-curable adhesive is preferable because the thickness of the adhesive layer can be reduced.

  Examples of the water-based adhesive include those containing a water-soluble or water-dispersible polymer such as a vinyl polymer, a gelatin, a vinyl latex, a polyurethane, an isocyanate, a polyester, and an epoxy. The adhesive layer made of such an aqueous adhesive is formed by applying an aqueous solution on a film and drying the film. In preparing the aqueous solution, a catalyst such as a cross-linking agent, other additives, or an acid may be added, if necessary.

  Examples of the crosslinking agent to be incorporated in the water-based adhesive include boric acid and borax; carboxylic acid compounds; alkyl diamines; isocyanates; epoxies; monoaldehydes; dialdehydes; amino-formaldehyde resins; Examples thereof include salts of valent metals and oxides thereof.

  The active energy ray-curable adhesive is an adhesive capable of undergoing radical polymerization, cationic polymerization, or anionic polymerization by irradiation with an active energy ray such as an electron beam or an ultraviolet ray. Above all, a photo-radical polymerizable adhesive whose radical polymerization starts by irradiation with ultraviolet rays is preferable because it can be cured with low energy.

Examples of the monomer of the radical polymerizable adhesive include a compound having a (meth) acryloyl group and a compound having a vinyl group. Among them, compounds having a (meth) acryloyl group are preferred. Examples of the compound having a (meth) acryloyl group include alkyl (meth) acrylates such as _C1-20 chain alkyl (meth) acrylate, alicyclic alkyl (meth) acrylate, and polycyclic alkyl (meth) acrylate; Included (meth) acrylates; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; Radical polymerizable adhesives include hydroxyethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, (meth) acrylamide, (meth) acryloylmorpholine And the like. Radical polymerizable adhesives include, as crosslinking components, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO-modified diacrylate. It may contain a polyfunctional monomer such as glycerin tetraacrylate.

  The photocurable adhesive such as a photoradical polymerizable adhesive preferably contains a photopolymerization initiator. The photopolymerization initiator may be appropriately selected according to the reaction species. For example, it is preferable to mix a radically polymerizable adhesive with a photoradical generator that generates radicals by light irradiation as a photopolymerization initiator. Specific examples of the photo radical generator will be described later. The content of the photoradical generator is usually about 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the monomer. When the radical polymerizable adhesive is used as an electron beam curable adhesive, a photopolymerization initiator is not particularly required. If necessary, a photosensitizer represented by a carbonyl compound or the like can be added to the radical polymerizable adhesive. Photosensitizers are used to increase the curing speed and sensitivity by electron beams. The amount of the photosensitizer to be used is generally about 0.001 to 10 parts by weight, preferably 0.01 to 3 parts by weight, based on 100 parts by weight of the monomer.

  The adhesive may contain an appropriate additive as needed. Examples of additives include silane coupling agents, coupling agents such as titanium coupling agents, adhesion promoters such as ethylene oxide, ultraviolet absorbers, deterioration inhibitors, dyes, processing aids, ion trapping agents, and antioxidants. , Tackifiers, fillers, plasticizers, leveling agents, foam inhibitors, antistatic agents, heat stabilizers, hydrolysis stabilizers and the like.

<Light curing of adhesive>
As described above, in the oriented liquid crystal film 1, the ratio of the horizontal load in the depth direction can be adjusted by adjusting the light irradiation amount at the time of photocuring of the polymer of the photopolymerizable liquid crystal compound. If the unreacted photopolymerization initiator remains in the oriented liquid crystal film, polymerization (photocuring) of the photopolymerizable liquid crystal compound of the oriented liquid crystal film 1 may proceed by light irradiation when the adhesive is cured. .

When the photo-curing of the oriented liquid crystal film proceeds during the photo-curing of the adhesive layer 3, the hardness of the portion having a greater depth than the vicinity of the surface layer (interface) becomes relatively higher, and the light of the liquid crystalline composition becomes higher. F ₃₀ / F ₁₅ may be larger than immediately after curing. In order to keep F ₃₀ / F ₁₅ of the oriented liquid crystal film in an appropriate range, it is preferable to suppress the photocuring of the oriented liquid crystal film during light irradiation for curing the adhesive.

  In order to suppress the curing of the oriented liquid crystal film at the time of photocuring the adhesive, for example, at the time of photocuring the adhesive, irradiate light having a longer wavelength than the irradiation light for photocuring the liquid crystalline composition. I just need. If light of a relatively long wavelength is irradiated during the photocuring of the adhesive, the photocuring of the oriented liquid crystal film having sensitivity to the short wavelength light hardly progresses. Can be suppressed.

The wavelength of light to be applied during photocuring mainly depends on the sensitivity wavelength of the photopolymerization initiator contained in the composition. Therefore, it is preferable that the photopolymerization initiator contained in the photocurable adhesive has a longer wavelength sensitivity than the photopolymerization initiator contained in the liquid crystalline composition. More specifically, the photopolymerization initiator contained in the photocurable adhesive preferably has sensitivity at a wavelength longer than 380 nm, and more preferably has sensitivity at a wavelength longer than 400 nm. As the photocurable adhesive, it is preferable to use a photopolymerization initiator having an absorption coefficient at a wavelength of 405 nm of 1 × 10 ² [mLg ⁻¹ cm ⁻¹ ] or more. The photopolymerization initiator having long-wavelength light sensitivity may have sensitivity to light having a wavelength of 400 nm or less.

  Specific examples of the photopolymerization initiator having a photosensitivity of a wavelength of 400 nm or more include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucirin TPO” manufactured by BASF) and 2,4,6-trimethylbenzoylphenylethoxyphos. Acylphosphine oxides such as fin oxide (“Lucirin TPO-L” manufactured by BASF); 2-benzyl-2-dimethylamino-1- (41-morpholinophenyl) butanone-1 (“Irgacure 369” manufactured by BASF) Amino ketones; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (“IRGACURE 819” manufactured by BASF), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide ( BASF “C GI403 ") and the like.

  As the photopolymerization initiator having long-wavelength photosensitivity, a photoradical generator that generates a radical by hydrogen abstraction may be used. Examples of the hydrogen abstraction type photopolymerization initiator include a thioxanthone-based photopolymerization initiator and a benzophenone-based photopolymerization initiator. A thioxanthone-based photopolymerization initiator (photoradical generator) is preferable because the radical generation efficiency by light having a wavelength longer than 380 nm is high and the absorption of visible light is small. Examples of the thioxanthone-based photoradical polymerization initiator include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone.

  By using a photopolymerization initiator having long-wavelength photosensitivity and a photopolymerization initiator having low long-wavelength photosensitivity in combination, the photopolymerization initiator having long-wavelength photosensitivity acts as a sensitizer, Radicals can also be generated in a photopolymerization initiator having a small wavelength photosensitivity. Further, a sensitizer for radical photopolymerization such as thiopyrylium salt, merocyanine, quinoline, stilquinoline, aryl ketone, aromatic ketone, ketocoumarin derivative, anthracene derivative, and a photopolymerization initiator may be used in combination.

  As a long-wavelength light source used for photocuring the adhesive, a gallium-enclosed metal halide lamp, an LED light source emitting light in a wavelength range of 380 to 440 nm, and the like are preferable. Alternatively, use a light source that includes ultraviolet light and visible light such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, and a xenon lamp, and use a wavelength selection filter such as a band-pass filter or a long-pass filter to obtain a short wavelength. Ultraviolet rays may be shielded. Light from a gallium-enclosed metal halide lamp or an LED light source may be irradiated via a wavelength filter to cure the adhesive.

The integrated irradiation light amount at the time of photocuring of the adhesive is, for example, about 100 to 2000 mJ / cm ² , and may be appropriately adjusted according to the composition and thickness of the photocurable adhesive. When the adhesive is photocured by irradiating light having a longer wavelength than that at the time of photocuring the liquid crystalline composition, the integrated irradiation light amount of UVV (ultraviolet-visible light having a wavelength of 395 to 445 nm) is within the above range. Is preferred.

In order to suppress the progress of photo-curing of the oriented liquid crystal film during photo-curing of the adhesive, the photo-polymerization initiator contained in the liquid crystal composition is more than the photo-polymerization initiator contained in the photo-curable adhesive. Also, those which have photosensitivity at short wavelength and do not show photosensitivity at long wavelength light are preferable. As the photopolymerization initiator having no long-wavelength photosensitivity, those having an extinction coefficient at a wavelength of 405 nm of less than 1 × 10 ² [mLg ⁻¹ cm ⁻¹ ] are preferable. The photopolymerization initiator contained in the liquid crystal composition preferably has an absorption coefficient at a wavelength of 405 nm of less than 1 × 10 ² [mLg ⁻¹ cm ⁻¹ ]. The photopolymerization initiator contained in the liquid crystal composition preferably has an extinction coefficient at 302 nm of 1 × 10 ² [mLg ⁻¹ cm ⁻¹ ] or more.

  As a photopolymerization initiator having no photosensitivity of long wavelength light, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, photoactive oxime photopolymerization initiator, Examples include a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and a titanocene-based photopolymerization initiator.

  Specific examples of the photopolymerization initiator that does not exhibit long-wavelength light sensitivity include benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, hydroxycyclohexylphenyl ketone (“IRGACURE 184” manufactured by BASF), 2, 2-dimethoxy-1,2-diphenylethan-1-one (“IRGACURE 651” manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (“IRGACURE 1173” manufactured by BASF), 1 -[4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one ("IRGACURE 2959" manufactured by BASF), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (“IRGACURE 907” manufactured by BASF), 2- ( Methylamino) -1- (4-morpholinophenyl) -2-benzyl-1-butanone (“IRGACURE 369” manufactured by BASF), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl- Propionyl) -benzyl] phenyl} -2-methyl-propan-1-one (“IRGACURE 127” manufactured by BASF), benzyl methyl ketal (“Esacure KB1” manufactured by DKSH), 2-hydroxy-2-methyl- [4- ( [1-Methylvinyl) phenyl] propanol oligomer ("Esacure KIP150" manufactured by DKSH).

[Image display device]
An image display device can be formed by attaching the oriented liquid crystal film 1 to the surface of an image display cell 50 such as a liquid crystal cell or an organic EL cell via the adhesive layer 2. As described above, in forming an image display device, it is preferable to use an optical film with an adhesive in which an adhesive layer 2 is provided on the surface of an oriented liquid crystal film 1 in advance. The optical film with an adhesive is provided with an adhesive layer 2 for bonding to an image display cell on one side of an oriented liquid crystal film 1 and another film 4 on the other side via an adhesive layer 3. It may be matched.

  After bonding the optical film with the adhesive to the image display cell, if a bonding failure occurs, or if a defect due to a defect or the like of the optical film is detected, peel the optical film from the image display cell. Work (rework) is performed. If there is a locally low strength (hardness) portion in the thickness direction of the film, cohesive failure occurs locally in the low strength portion due to the peeling force at the time of rework, which may cause rework failure. . In the present invention, since the hardness distribution in the thickness direction of the oriented liquid crystal film is within a predetermined range, cohesive failure of the oriented liquid crystal film hardly occurs and the reworkability is excellent. Therefore, by using the oriented liquid crystal film of the present invention, the production efficiency of the image display device can be improved and the yield of the product can be expected to be improved.

  Hereinafter, the present invention will be described in more detail with reference to production examples of homeotropic alignment liquid crystal films, but the present invention is not limited to the following examples.

[Preparation of liquid crystalline composition]
20 parts by weight of a side chain type liquid crystal polymer having a weight average molecular weight of 5,000 of the following chemical formula (n = 0.35, and shown as a block polymer for convenience), a polymerizable liquid crystal compound exhibiting a nematic liquid crystal phase (“Palicolor” manufactured by BASF) LC242 "), 80 parts by weight, and 5 parts by weight of 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (" IRGACURE 907 "manufactured by BASF) as a photopolymerization initiator were added to cyclopentane. The liquid crystalline composition was dissolved in 400 parts by weight of NON to prepare a liquid crystalline composition.

[Preparation of oriented liquid crystal film]
As a film substrate, a biaxially stretched norbornene-based film having a slippery layer on one surface (“Zeonor Film” manufactured by Zeon Corporation, thickness: 33 μm, in-plane retardation: 135 nm, arithmetic mean roughness of the surface without the slippery layer) (1.0 nm). The above liquid crystalline composition was applied to the surface of the film substrate on which the smooth layer was not formed by a bar coater so that the thickness after drying was 1 μm, and heated at 80 ° C. for 2 minutes to align the liquid crystal. Thereafter, the alignment was fixed by cooling to room temperature, and an ultraviolet ray (UVA: 320 to 390 nm) having an integrated amount shown in Table 1 was irradiated under a nitrogen atmosphere to photo-cure the liquid crystal monomer to prepare an oriented liquid crystal film. . UV irradiation was performed by using an H bulb of an electrodeless UV lamp system (“LIGHT HAMMER 10” manufactured by Heraeus), and the integrated amount of UVA was measured by a UV illuminance measuring system (“UV Power Puck II” manufactured by Heraeus).

[Preparation of optical film with adhesive]
62 parts by weight of hydroxyethylacrylamide ("HEAA" manufactured by Kojin), 25 parts by weight of acryloylmorpholine ("ACMO" manufactured by Kojin), 7 parts by weight of PEG400 # diacrylate ("Light Acrylate 9EG-A" manufactured by Kyoeisha Chemical), and 3 parts by weight of 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (“IRGACURE 907” manufactured by BASF) as a photopolymerization initiator and 2,4-diethylthioxanthone (Nippon Kayaku) ("Kayacure DETX-S") was mixed to prepare a photocurable adhesive composition. The photocurable adhesive composition was applied in a thickness of 1μm on the surface of the stretched phase difference film having a thickness of 48 [mu] m, after attaching the alignment liquid crystal film of the over coating layer of the adhesive, the integrated light quantity 700 mJ / cm ² The adhesive was cured by irradiation with ultraviolet-visible light (UVV: 395 to 445 nm). For the irradiation of ultraviolet rays, a short-wavelength light was cut by a long-pass filter having a cut-on wavelength of 380 nm using a V bulb of an electrodeless UV lamp system (“LIGHT HAMMER 10” manufactured by Heraeus). The integrated light quantity of UVV was measured by a UV illuminance measuring system (“UV Power Puck II” manufactured by Heraeus).

  The film substrate is peeled off from the oriented liquid crystal film, an easily adhesive layer having a thickness of about 30 nm is formed on the surface of the oriented liquid crystal film, and an acrylic pressure-sensitive adhesive sheet having a thickness of 15 μm is stuck thereon to obtain an optical film with an adhesive. Was.

[Evaluation]
<Horizontal load>
The oriented liquid crystal film (attached on the film substrate) before bonding the stretched film was fixed on a stage of a nanoindentation system (“TI950 TriboIndenter” manufactured by Hysitron). A load is applied using a barco pitch (triangular pyramid) diamond indenter (radius of curvature at the tip: 0.1 μm), and the stage is pushed down to a depth of 15 nm, and the stage is horizontally moved by 10 μm (moving speed: 0.5 μm / sec). was the maximum value of the load in the range of up to horizontal movement distance 0.2μm and horizontal load F _15. Change the indentation depth of the indenter to 30 nm, was measured horizontal load F ₃₀ in the same manner.

<Anchoring force>
The optical film with an adhesive was cut into a width of 50 mm and a length of 200 mm, and the surface on the stretched retardation film side was bonded to a glass plate with a double-sided tape. An ITO film cut into a width of 25 mm and a length of 200 mm was attached to an acrylic pressure-sensitive adhesive sheet of an optical film with a pressure-sensitive adhesive, and left at room temperature for 20 minutes to obtain a measurement sample. The peeling force (peeling force at the interface between the oriented liquid crystal film and the acrylic pressure-sensitive adhesive layer) determined by a 180 ° peel test at a tensile speed of 300 mm / min using a tensile compression tester (“TCM-1kNB” manufactured by Minebea). The anchoring force was used.

<Reworkability>
The polarizing plate with an adhesive was cut out into a rectangle of 150 mm × 150 mm, and the optical film with the adhesive was bonded to a Corning-free non-ali glass plate using a hand roller. The film was peeled from the glass plate in a direction parallel to the long side from the short side, and the presence or absence of an adhesive or the like on the surface of the glass plate was confirmed. This rework test was performed 10 times for each sample, and the reworkability was determined according to the following criteria.
〇: Good rework was achieved without any residue on the glass surface for all 10 samples. Δ: Residue (defective rework) on the glass surface was observed on 1 to 3 samples. ×: 4 samples In the above samples, residue on the glass surface (defective rework) was observed.

Table 1 shows the integrated light amount of the oriented liquid crystal film during photocuring and the evaluation results of each experimental example, and FIG. 4 shows a graph in which the integrated light amount and the horizontal load of the oriented liquid crystal film are plotted. FIG. 5 shows a cross-sectional image of an optical film with a pressure-sensitive adhesive manufactured using the oriented liquid crystal film of Sample 3 (integrated light quantity: 250 mJ / cm ² ) by a transmission electron microscope (TEM).

In Sample 1 having an integrated light amount of 50 mJ / cm ² , F ₃₀ / F ₁₅ of the oriented liquid crystal film was small, and a rework defect occurred. On the other hand, integrated light quantity in 450 mJ / cm ² or more samples 5-8, large _F 30 _{/ F 15} of the alignment liquid crystal _film, anchor force with increasing F 30 _{/ F 15} is tended to decrease, rework A defect had occurred.

As shown in FIG. 4, as the integrated quantity of light when the light curing of alignment liquid crystal film is increased, the tendency for the horizontal load F ₃₀ increases were seen at depth 30 nm. Horizontal load F ₁₅ at a depth 15nm, although slowly increases with the increase of the integrated light quantity, weight increase as compared to the F ₃₀ was small. Therefore, it can be seen that F ₃₀ / F ₁₅ tends to increase as the integrated light amount increases.

  As shown in the TEM image of FIG. 5, the oriented liquid crystal film has an interface on the pressure-sensitive adhesive layer side (the substrate surface when the oriented liquid crystal film is produced) and an interface on the adhesive layer side (the air surface when the oriented liquid crystal film is produced). Regions with different contrast were observed. When the composition of the oriented liquid crystal film in the thickness direction was analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), the concentration of the side chain liquid crystal polymer was high near the interface, and the polymer of the liquid crystal monomer was It was confirmed that the concentration was relatively low (data not shown).

These results, alignment liquid crystal film whereas the vicinity of the interface (depth 15nm approximately regions) the polymer concentration F ₁₅ hardly changes even when irradiated with light for high monomer is away from the interface region concentration with the progress of polymerization by light irradiation due to _high, believed to _{F 30} is increased. When F ₃₀ / F ₁₅ is small (for example, less than 1) as in Sample 1, the photocuring is insufficient and the overall strength of the oriented liquid crystal film is insufficient. It is considered that cohesive failure of the liquid crystal film occurred, which caused rework failure. On the other hand, when photocuring proceeds excessively, F ₃₀ / F ₁₅ increases, and the difference in hardness between the vicinity of the interface of the oriented liquid crystal film and the center in the thickness direction becomes remarkable. It is considered that rework failure occurred due to the fact that destruction is likely to occur.

On the other hand, in Samples 2 to 4 in which F ₃₀ / F ₁₅ is within the predetermined range, the liquid crystal monomer is sufficiently cured, so that the hardness of the oriented liquid crystal film is ensured and the hardness distribution in the thickness direction is obtained. It is considered that cohesive failure due to local concentration of force was unlikely to occur due to the small, and good reworkability was exhibited.

1 Alignment liquid crystal film
11 Board surface
DESCRIPTION OF SYMBOLS 12 Air surface 2 Adhesive layer 3 Adhesive layer 4 Film 8 Film substrate 9 Separator 50 Image display cell

Alignment liquid crystal film, that put the depth 30nm from the surface horizontal load _{F 30} is preferably a 1.3 to 2.2 times the horizontal load _{F 15} that put the depth 15nm from the surface. For example, F ₃₀ / F ₁₅ of the oriented liquid crystal film can be adjusted by adjusting the amount of light irradiation when polymerizing or crosslinking the photopolymerizable liquid crystal compound. The integrated irradiation light amount at the time of polymerizing or crosslinking the photopolymerizable liquid crystal compound is preferably from 150 to 370 mJ / cm ² .

The present invention relates to an oriented liquid crystal film in which liquid crystal molecules are oriented, a method for manufacturing the same, and an image display device including the oriented liquid crystal film. Furthermore, the present invention is tacky optical film with adhesives on one surface provided with a pressure-sensitive adhesive layer of the aligned liquid crystal film and a manufacturing method thereof.

Alignment liquid crystal film of the present invention, horizontal load _{F 30} at a depth 30nm from the surface, which is 1 to 2.2 times the horizontal load _{F 15} at a depth 15nm from the surface. Horizontal load, pushing the indenter nanoindentator over a predetermined depth, the maximum load when the sample was moved relative to the horizontal direction (direction perpendicular to the depth direction). The horizontal load is an index indicating the hardness of the sample at a predetermined depth. The fact that the horizontal load varies depending on the indentation depth means that the sample has a hardness distribution in the depth direction.

A liquid crystal composition can be prepared by mixing a photopolymerizable liquid crystal compound, another compound (for example, a side chain type liquid crystal polymer), and a photopolymerization initiator with a solvent. The solvent is not particularly limited as long as it can dissolve the photopolymerizable liquid crystal compound and does not erode (or has low erosion) the film substrate. Chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene , tetrachlorethylene, chlorobenzene, halogenated hydrocarbons such as orthodichlorobenzene; phenols, phenols such as parametric chlorophenol; benzene, toluene, xylene, methoxybenzene, aromatic hydrocarbons such as 1,2-dimethoxybenzene; acetone Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone and N-methyl-2-pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol; Alcohol solvents such as Lyserine, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide A nitrile solvent such as acetonitrile and butyronitrile; an ether solvent such as diethyl ether, dibutyl ether and tetrahydrofuran; and ethylcellosolve and butylcellosolve. The concentration of the liquid crystal composition is usually about 3 to 50% by weight, preferably about 7 to 35% by weight.

The in-plane retardation _R0 of a stretched film used as a film substrate is generally 10 nm or more. When the film substrate is a stretched film having an in-plane retardation of 10 nm or more, the polymer constituting the film is preferentially oriented in a predetermined direction (slow axis direction or fast axis direction). Since the alignment of the polymer on the film substrate has an alignment regulating force for homogeneously aligning the liquid crystal molecules, when no vertical alignment film is provided, the homeotropic alignment of the liquid crystal molecules may be inhibited, and an alignment defect may occur. As will be described in detail later, by lowering the heating temperature when the liquid crystal molecules are homeotropically aligned, a homeotropically aligned liquid crystal film with few alignment defects can be obtained even when a stretched film substrate is used.

Method of applying a liquid composition to the film substrate is not particularly limited, a spin coating, die DOO, kiss roll coating, gravure coating, reverse coating, spray coating, Meyer bar coating, knife roll coating, air knife coating or the like Can be adopted. After applying the solution, the solvent is removed to form a liquid crystal composition layer on the film substrate. The coating thickness is preferably adjusted so that the thickness of the liquid crystal composition layer after drying the solvent (the thickness of the oriented liquid crystal film) is about 0.5 to 7 μm.

When an adhesive layer is provided on the air surface 12 of the oriented liquid crystal film 1, the adhesive layer may be laminated on the air surface 12 in a state where the oriented liquid crystal film 1 is provided on the film substrate 8 (see FIG. 2A). . If the air surface 11 of the alignment liquid crystal film 1 is provided a pressure-sensitive adhesive layer is peeled off the film substrate 8 from alignment liquid crystal film 1, after exposing the substrate surface 11 of the alignment liquid crystal film 1, pressure sensitive adhesive on the substrate surface 11 The layer 2 may be stacked.

[Evaluation]
<Horizontal load>
The oriented liquid crystal film (attached on the film substrate) before bonding the stretched film was fixed on a stage of a nanoindentation system (“TI950 TriboIndenter” manufactured by Hysitron). Barcode bi pitch (triangular pyramid) type diamond indenter (tip radius of curvature: 0.1 [mu] m) was used to apply a load, indentation depth 15 nm, the stage was 10μm horizontal movement (movement speed 0.5μm / sec), and the maximum value of the load in the range of up to horizontal movement distance 0.2μm and horizontal load _{F 15.} Change the indentation depth of the indenter to 30 nm, was measured horizontal load F ₃₀ in the same manner.

Claims (15)

An oriented liquid crystal film comprising a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction,
Including two or more compounds, at least one of which is a polymer of a photopolymerizable liquid crystal compound,
An oriented liquid crystal film, wherein the horizontal load at a depth of 30 nm from the surface is 1 to 2.2 times the maximum horizontal load at a depth of 15 nm from the surface.   The oriented liquid crystal film according to claim 1, wherein the two or more compounds include a polymer of a side chain liquid crystal polymer and a photopolymerizable liquid crystal compound.   The oriented liquid crystal film according to claim 2, wherein the side chain type liquid crystal polymer has a monomer unit containing a liquid crystal fragment side chain and a monomer unit containing a non-liquid crystal fragment side chain.   The aligned liquid crystal film according to any one of claims 1 to 3, wherein the liquid crystal molecules are homeotropically aligned.   An optical film with an adhesive, comprising: the oriented liquid crystal film according to claim 1; and an adhesive layer provided on a first main surface of the oriented liquid crystal film.   The optical film with a pressure-sensitive adhesive according to claim 5, further comprising another film bonded to the second main surface of the oriented liquid crystal film via an adhesive layer.   An image display device, wherein the oriented liquid crystal film according to any one of claims 1 to 4 is attached to a surface of the image display cell via an adhesive layer. A method for producing an oriented liquid crystal film comprising a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction,
A coating step of coating a liquid crystal composition containing a liquid crystal compound on a first main surface of a film substrate having a first main surface and a second main surface;
A liquid crystal alignment step of heating the liquid crystal composition to align liquid crystal molecules in a predetermined direction; and a photopolymerization step of polymerizing or crosslinking the liquid crystal compound by light irradiation,
The liquid crystal composition includes two or more compounds, at least one of which is a photopolymerizable liquid crystal compound,
A method for producing an oriented liquid crystal film, wherein the integrated irradiation light amount in the photopolymerization step is 100 to 370 mJ / cm ² .   The alignment according to claim 8, wherein, after the photopolymerization step, the maximum horizontal load at a depth of 30 nm from the surface of the oriented liquid crystal film is 1 to 2.2 times the maximum horizontal load at a depth of 15 nm from the surface. Liquid crystal film manufacturing method.   The method for producing an oriented liquid crystal film according to claim 8, wherein the two or more compounds include a side chain type liquid crystal polymer and a photopolymerizable liquid crystal compound.   The method for producing an oriented liquid crystal film according to claim 10, wherein the side chain type liquid crystal polymer has a monomer unit containing a liquid crystal fragment side chain and a monomer unit containing a non-liquid crystal fragment side chain.   The method for producing an oriented liquid crystal film according to any one of claims 8 to 11, wherein an orientation film is not provided on the first main surface of the film substrate.   The method for producing an oriented liquid crystal film according to claim 12, wherein the film substrate is a stretched film having an in-plane retardation of 10 to 500 nm. An oriented liquid crystal film composed of a liquid crystal layer in which liquid crystal molecules are oriented in a predetermined direction, an adhesive layer provided on a first main surface of the oriented liquid crystal film, and an adhesive layer on a second main surface of the oriented liquid crystal film. A method for producing an optical film with a pressure-sensitive adhesive comprising another laminated film,
A laminate in which an oriented liquid crystal film is provided on a film substrate by the method according to any one of claims 8 to 12, and a first principal surface of the film substrate and a first principal surface of the oriented liquid crystal film are in contact with each other. To form
On the second main surface of the oriented liquid crystal film, another film is bonded via an adhesive layer,
Peeling a film substrate from the oriented liquid crystal film,
Laminating an adhesive layer on the second main surface of the oriented liquid crystal film,
A method for producing an optical film with an adhesive. The adhesive layer is a photo-curable adhesive,
The light irradiated for photo-curing the adhesive is light having a longer wavelength than the light irradiated for curing the photo-polymerizable liquid crystal compound in the photo-polymerization step in forming the oriented liquid crystal film. A method for producing an optical film with a pressure-sensitive adhesive according to claim 14.