JP2017111394A - Manufacturing method for optical films - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for optical films, which allows for manufacturing an optical film with a hardened layer having good surface condition using a high-temperature back roll.SOLUTION: Disclosed is a manufacturing method for an optical film comprising an elongate base material film and a hardened layer, the method comprising steps of: heating a base material film of a multilayer film comprising the base material film and a pre-hardening layer that can be cured by active energy rays while an effective portions of the base material film is in the air; and curing the pre-hardening layer to obtain a hardened layer by irradiating the pre-hardening layer with active energy rays while the heated base material film is in contact with a back roll kept at a temperature of 30°C or higher.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an optical film having a base film and a cured layer.

  As an optical film, a film having a multilayer structure including a base film and a functional layer provided on the base film is known. In such an optical film, the optical function of the optical film is usually realized by appropriate optical characteristics of the functional layer. As an example of a method for producing such an optical film, a step of forming a pre-curing layer by applying a coating solution corresponding to the functional layer on the base film, and curing the pre-curing layer to obtain a desired layer The manufacturing method including the process of obtaining a functional layer as a hardened layer is known (refer patent documents 1-4).

JP 2005-234554 A JP 2005-254691 A JP 2011-227488 A JP 2013-184119 A

  In the method for producing an optical film as described above, the cured layer can be formed of a resin containing a polymer. Moreover, as a coating liquid corresponding to the said hardened layer, the liquid containing the monomer which can produce | generate the said polymer can be used. As an optical film manufacturing method using a coating liquid containing a monomer, for example, an optical film having an optical anisotropic layer as a cured layer is manufactured using a coating liquid containing a photopolymerizable liquid crystal compound as a monomer. The manufacturing method to do is mentioned.

  In such an optical film manufacturing method, it may be desired to reduce the residual monomer contained in the cured layer. For example, in the method for producing an optical film including an optically anisotropic layer as described above, it is preferable to reduce the amount of residual monomer in the optically anisotropic layer according to the study by the applicant (Japanese Patent Application No. 2015-036854). Issue).

  As a method for reducing the amount of residual monomer, the present inventor has studied a method in which the back roll supporting the base film is heated to a temperature higher than room temperature in the step of curing the pre-curing layer. By increasing the temperature of the back roll, the reaction temperature during the curing reaction can be increased, so that the reaction of the monomer can be promoted, and as a result, the amount of residual monomer can be reduced.

  However, the inventors further studied and found that the surface state of the cured layer of the produced optical film can be deteriorated when the back roll is heated to a high temperature. For example, when an optical film including an optically anisotropic layer is manufactured as a cured layer, when the optical film is observed between a pair of polarizing plates, a striped planar failure extending in the film transport direction is observed. sell. Such a surface failure may occur in an unnecessary portion (for example, an end portion in the width direction) of the optical film, but it is desired to suppress it in a product portion of the optical film.

  The present invention was devised in view of the above problems, and an object thereof is to provide an optical film manufacturing method capable of manufacturing an optical film having a cured layer with a good surface state while using a high-temperature back roll. To do.

The present inventor has intensively studied to solve the above-described problems. As a result, the inventor caused wrinkles due to thermal expansion in the base film in contact with the back roll during the period in which the base film was supported by the back roll, and this wrinkle caused a planar failure in the cured layer. I found out. And this inventor can suppress generation | occurrence | production of the surface failure of a hardened layer by suppressing generation | occurrence | production of the wrinkle of a base film by heating a base film beforehand before contacting a back roll. Discovered and completed the present invention.
That is, the present invention is as follows.

[1] A method for producing an optical film comprising a long base film and a cured layer,
Heating the base film of a multilayer film comprising the base film and a pre-curing layer that can be cured by active energy rays, with an effective portion of the base film in the air; and
A process of obtaining the cured layer by curing the pre-cured layer by irradiating the pre-cured layer with active energy rays in a state where the heated base film is in contact with a back roll of 30 ° C. or higher. And a method for producing an optical film.
[2] The method for producing an optical film according to [1], wherein the temperature T _base of the heated _base film and the temperature T _{br of the} back roll satisfy the following formula (i).
T _base −T _br > −5 ° C. (i)
[3] The tensile elastic modulus in the width direction of the base film is 2500 MPa or less,
The method for producing an optical film according to [1] or [2], wherein the base film has a thickness of 50 μm or less.
[4] The method for producing an optical film according to any one of [1] to [3], wherein the cured layer can be peeled from the base film, or can be transferred to another member. .

  According to the production method of the present invention, an optical film having a cured layer with a good surface state can be produced while using a high-temperature back roll.

FIG. 1 is a front view schematically showing a production apparatus used in the method for producing an optical film according to one embodiment of the present invention. FIG. 2 is a plan view schematically showing a base film used in the method for producing an optical film according to one embodiment of the present invention. FIG. 3 shows that a multi-layer film in which the base film is brought into contact with the peripheral surface of the back roll without cutting the base film before contacting the back roll is cut along a plane perpendicular to the transport direction of the multi-layer film. It is sectional drawing which shows the obtained cross section typically. FIG. 4 shows that a multilayer film in which the base film is brought into contact with the peripheral surface of the back roll without cutting the base film before contacting the back roll is cut along a plane perpendicular to the transport direction of the multilayer film. It is sectional drawing which shows the obtained cross section typically.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

  In the following description, “long” film refers to a film having a length of usually 5 times or more, preferably 10 times or more of the width, specifically, A film having such a length that it is wound up in a roll and stored or transported.

  In the following description, “polarizing plate” and “wave plate” include not only rigid members but also flexible members such as resin films.

  In the following description, the in-plane retardation Re of a layer is a value represented by Re = (nx−ny) × d unless otherwise specified. Here, nx represents a refractive index in a direction (in-plane direction) perpendicular to the thickness direction of the layer and giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and perpendicular to the nx direction. d represents the thickness of the layer. These retardations can be measured using a commercially available phase difference measuring apparatus or the Senarmon method.

  In the following description, the slow axis of a layer represents the slow axis in the in-plane direction of the layer unless otherwise specified.

[1. Outline of Embodiments Related to Manufacturing Method of Optical Film]
The method for producing an optical film according to an embodiment of the present invention,
1. Preparing a multilayer film comprising a long base film and a pre-curing layer that can be cured by active energy rays;
2. Heating the substrate film of the multilayer film with an effective portion of the multilayer film in the air; and
3. A step of curing the pre-curing layer to obtain a cured layer by irradiating the pre-curing layer with active energy rays in a state where the heated base film is in contact with the back roll.
According to this manufacturing method, an optical film provided with a base film and a cured layer provided on the base film is obtained.

  In the present embodiment, a manufacturing method for manufacturing an optical film having an optically anisotropic layer as a cured layer using a multilayer film having a pre-curing layer containing a photopolymerizable liquid crystal compound will be described as an example. To do.

[2. Base film]
As the base film, any film applicable to an optical film can be used. In particular, the base film is preferably a film having a small tensile modulus in the width direction. Specifically, the tensile elastic modulus is preferably 2500 MPa or less, more preferably 2400 MPa or less, and particularly preferably 2300 MPa or less. Since the base film having a small tensile modulus in the width direction has high flexibility, it is likely to be deformed in the width direction. Therefore, since the base film in which the tensile modulus in the width direction is within the above range is easily wrinkled according to the conventional manufacturing method, it is difficult to obtain a cured layer having a good surface state. On the other hand, according to the manufacturing method according to the present embodiment, it is possible to obtain a cured layer having a good surface state even when such a highly flexible base film is used. Therefore, it is preferable that the tensile elastic modulus in the width direction of the base film falls within the above range from the viewpoint of solving the problems that have been particularly difficult to solve in the past. The lower limit of the tensile elastic modulus is arbitrary, but is preferably 100 MPa or more, more preferably 150 MPa or more, and particularly preferably 200 MPa or more from the viewpoint of improving the handleability of the base film.

  Although the thickness of a base film can be set according to the use of an optical film, it is preferable that it is thin. Specifically, the thickness is preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less. Thin base films are usually prone to deformation. Therefore, the base film whose thickness falls within the above range easily wrinkles according to the conventional manufacturing method, and it is difficult to obtain a cured layer having a good surface state. On the other hand, according to the manufacturing method which concerns on this embodiment, even when such a thin base film is used, it is possible to obtain a hardened layer with a favorable surface state. Therefore, it is preferable that the thickness of the base film falls within the above-mentioned range from the viewpoint of solving the problem that has been particularly difficult to solve in the past. Although the minimum of the said thickness is arbitrary, from a viewpoint which makes manufacture of a base film easy, Preferably it is 5 micrometers or more, More preferably, it is 7 micrometers or more, Most preferably, it is 10 micrometers or more. However, when a resin film containing triacetyl cellulose is used as the base film, the thickness of the base film is preferably 20 μm to 150 μm, more preferably 30 μm to 130 μm, and still more preferably 60 μm to 120 μm.

  The material of the base film is not particularly limited, and various resins can be used. Examples of the resin include resins containing various polymers. Examples of the polymer include an alicyclic structure-containing polymer, cellulose ester, polyvinyl alcohol, polyimide, UV transparent acrylic, polycarbonate, polysulfone, polyethersulfone, epoxy polymer, polystyrene, and combinations thereof. Among these, from the viewpoints of transparency, low hygroscopicity, dimensional stability, lightness, and the like, alicyclic structure-containing polymers and cellulose esters are preferable, and alicyclic structure-containing polymers are more preferable.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in a repeating unit, and is usually an amorphous polymer. As the alicyclic structure-containing polymer, any of a polymer containing an alicyclic structure in the main chain and a polymer containing an alicyclic structure in the side chain can be used.
Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability.
The number of carbon atoms constituting one repeating unit of the alicyclic structure is not particularly limited, but is preferably 4 or more, more preferably 5 or more, particularly preferably 6 or more, preferably 30 or less, more The number is preferably 20 or less, particularly preferably 15 or less.

  The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer can be appropriately selected depending on the purpose of use, but is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably. 90% by weight or more. By increasing the number of repeating units having an alicyclic structure as described above, the heat resistance of the base film can be increased.

  Examples of the alicyclic structure-containing polymer include (1) norbornene polymer, (2) monocyclic olefin polymer, (3) cyclic conjugated diene polymer, (4) vinyl alicyclic hydrocarbon polymer, And hydrogenated products thereof. Among these, a norbornene polymer is more preferable from the viewpoint of transparency and moldability.

  Examples of norbornene polymers include, for example, ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers with other monomers capable of ring-opening copolymerization, and hydrogenated products thereof; addition polymers of norbornene monomers; Examples include addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, a ring-opening polymer hydrogenated product of norbornene monomer is particularly preferable from the viewpoint of transparency.

  Said alicyclic structure containing polymer is chosen from the well-known polymer currently disclosed by Unexamined-Japanese-Patent No. 2002-321302 etc., for example.

  The glass transition temperature of the alicyclic structure-containing polymer is preferably 80 ° C. or higher, more preferably 100 ° C. to 250 ° C. An alicyclic structure-containing polymer having a glass transition temperature in such a range is less susceptible to deformation and stress during use at high temperatures, and is excellent in durability.

  The weight average molecular weight (Mw) of the alicyclic structure-containing polymer is preferably 10,000 to 100,000, more preferably 25,000 to 80,000, and even more preferably 25,000 to 50,000. . When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the base film are highly balanced and suitable. The weight average molecular weight is determined by gel permeation chromatography (hereinafter abbreviated as “GPC”) using cyclohexane (toluene when the resin is not dissolved) as a solvent (in terms of polyisoprene). Sometimes it can be measured by the value of polystyrene).

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer is preferably 1 or more, more preferably 1.2 or more, preferably 10 or less, more preferably 4 or less, particularly preferably 3.5 or less.

The resin containing the alicyclic structure-containing polymer may be composed only of the alicyclic structure-containing polymer, but may contain any compounding agent as long as the effects of the present invention are not significantly impaired. The ratio of the alicyclic structure-containing polymer in the resin containing the alicyclic structure-containing polymer is preferably 70% by weight or more, more preferably 80% by weight or more.
Preferable specific examples of the resin containing the alicyclic structure-containing polymer include “Zeonor 1420” and “Zeonor 1420R” manufactured by Nippon Zeon.

  The cellulose ester is typically a lower fatty acid ester of cellulose (eg, cellulose acetate, cellulose acetate butyrate and cellulose acetate propionate). Lower fatty acid means a fatty acid having 6 or less carbon atoms per molecule. Cellulose acetate includes triacetyl cellulose (TAC) and cellulose diacetate (DAC).

  The acetylation degree of cellulose acetate is preferably 50% to 70%, particularly preferably 55% to 65%. The weight average molecular weight is preferably 70,000 to 120,000, particularly preferably 80,000 to 100,000. The cellulose acetate may be esterified with not only acetic acid but also a part of fatty acid such as propionic acid and butyric acid. Moreover, resin which comprises a base film may contain combining cellulose acetate and cellulose esters (cellulose propionate, cellulose butyrate, etc.) other than cellulose acetate. In that case, it is preferable that all of these cellulose esters satisfy the above acetylation degree.

  When a film of triacetyl cellulose is used as the base film, such a film is prepared by dissolving triacetyl cellulose in a solvent substantially free of dichloromethane by a low temperature dissolution method or a high temperature dissolution method. A triacetyl cellulose film produced using a dope is particularly preferable from the viewpoint of environmental conservation. A film of triacetyl cellulose can be produced by a co-casting method. In the co-casting method, a solution (dope) containing raw material flakes and a solvent of triacetyl cellulose and optional additives is prepared, and the dope is cast from a dope feeder (die) onto a support. Then, the cast can be peeled off from the support as a film when the cast material is dried to some extent to give rigidity, and the film is further dried to remove the solvent. Examples of solvents for dissolving raw material flakes include halogenated hydrocarbon solvents (dichloromethane, etc.), alcohol solvents (methanol, ethanol, butanol, etc.), ester solvents (methyl formate, methyl acetate, etc.), ether solvents (dioxane, dioxolane, Diethyl ether and the like). Examples of the additive contained in the dope include a retardation increasing agent, a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a slipping agent, and a peeling accelerator. Examples of the support for casting the dope include a horizontal endless metal belt and a rotating drum. In casting, a single dope can be cast as a single layer, or a plurality of layers can be co-cast. When co-casting a plurality of layers, for example, a low concentration cellulose ester dope layer and a high concentration cellulose ester dope layer provided in contact with the front and back surfaces are formed. The dopes can be cast sequentially. As an example of the method of drying a film and removing a solvent, the method of conveying a film and allowing the inside to pass through the drying part set to the conditions suitable for drying is mentioned.

  Preferable examples of the triacetylcellulose film include known ones such as TAC-TD80U (manufactured by Fuji Photo Film Co., Ltd.), and those disclosed in JIII Journal of Technical Disclosure No. 2001-1745.

  The substrate film is preferably excellent in transparency in order to increase the degree of freedom in the manufacturing process. Specifically, the total light transmittance of the base film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more. The total light transmittance of the substrate can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet / visible spectrometer.

  In the production method for producing an optical film having an optically anisotropic layer as a cured layer, using a multilayer film having a pre-curing layer containing a photopolymerizable liquid crystal compound as in the example shown in the present embodiment, Usually, a substrate film having an orientation regulating force is used. The orientation regulating force of the base film refers to the property of the base film that can orient the photopolymerizable liquid crystal compound in the pre-cured layer formed on the base film.

  The orientation regulating force can be imparted by applying a treatment that imparts the orientation regulating force to the film that is the material of the base film. Examples of such treatment include stretching treatment and rubbing treatment.

  In a preferred embodiment, the substrate film is a stretched film. By setting it as this stretched film, a base film can be made into the film which has the orientation control power according to the extending | stretching direction.

  When the base film is a stretched film, the stretching direction is arbitrary. Therefore, the stretching may be only oblique stretching (stretching in a direction not parallel to both the longitudinal direction and the width direction of the base film), or only lateral stretching (stretching in the width direction of the base film). Only stretching (stretching in the longitudinal direction of the base film) may be performed, or these stretching may be performed in combination.

  In a more preferred embodiment, the base film is a diagonally stretched film. That is, the base film is preferably a film stretched in a direction non-parallel to both the longitudinal direction and the width direction of the film.

  When the base film is an obliquely stretched film, the angle formed by the stretching direction and the width direction of the base film can be specifically more than 0 ° and less than 90 °. By using such an obliquely stretched film, a cured layer as an optically anisotropic layer is transferred and laminated on a long linear polarizer by roll-to-roll, thereby enabling efficient production of a circularly polarizing plate. .

  In one embodiment, the angle formed between the stretching direction and the width direction of the base film is preferably 15 ° ± 5 °, 22.5 ± 5 °, 45 ° ± 5 °, or 75 ° ± 5 °, Preferably 15 ° ± 4 °, 22.5 ° ± 4 °, 45 ° ± 4 °, or 75 ° ± 4 °, even more preferably 15 ° ± 3 °, 22.5 ° ± 3 °, 45 ° ± It may be a specific range such as 3 ° or 75 ° ± 3 °. By having such an angular relationship, a circularly polarizing plate can be efficiently manufactured by transferring and laminating a cured layer as an optically anisotropic layer on a long linear polarizer by roll-to-roll.

The draw ratio can be appropriately set within the range in which the orientation regulating force is generated on the surface of the base film. When the base film uses a resin having positive intrinsic birefringence as a material, the molecules are oriented in the stretching direction and the orientation axis is expressed in the stretching direction.
Stretching can be performed using a known stretching machine such as a tenter stretching machine.

[3. Step of preparing a multilayer film]
Usually, a multilayer film is prepared by forming a pre-curing layer on the substrate film. The pre-curing layer is a layer that can be cured by irradiation with active energy rays. Here, the active energy rays may include light such as visible light, ultraviolet light, and infrared light, and arbitrary energy rays such as electron beams. In the manufacturing method according to this embodiment, the cured layer of the optical film is obtained by curing the pre-curing layer.

  The pre-curing layer is usually provided as a layer of the coating liquid by coating a coating liquid containing a component that can be contained in the pre-curing layer on the base film. As the coating liquid, an appropriate one can be used according to the intended cured layer. Usually, a coating solution containing a monomer, oligomer or polymerizable polymer that can cause a reaction such as polymerization and crosslinking upon irradiation with active energy rays is used. In the following description, the monomers, oligomers and polymerizable polymers mentioned above are sometimes collectively referred to as “monomer components”. By using the coating liquid as described above, a pre-curing layer containing a monomer component is obtained. And such a pre-hardening layer can be hardened | cured when reaction, such as superposition | polymerization and bridge | crosslinking, produces | generates said monomer component by irradiating an active energy ray.

  In the production method for producing an optical film having an optically anisotropic layer as a cured layer, using a multilayer film having a pre-curing layer containing a photopolymerizable liquid crystal compound as in the example shown in the present embodiment, Usually, a liquid crystal composition containing a photopolymerizable liquid crystal compound and optional components as required is used as the coating liquid.

  A liquid crystal compound is a compound that can exhibit a liquid crystal phase when blended and aligned in a liquid crystal composition. The photopolymerizable liquid crystal compound is a liquid crystal compound that can be polymerized in a liquid crystal composition in a state of exhibiting such a liquid crystal phase, and can be a polymer while maintaining molecular orientation in the liquid crystal phase. Further, in the following explanation, compounds that are components of a liquid crystal composition and have a polymerizable property (such as a photopolymerizable liquid crystal compound and other polymerizable compounds) are collectively referred to simply as “polymerizable compound”. is there.

  The photopolymerizable liquid crystal compound is a compound such as a liquid crystal compound having a polymerizable group, a compound capable of forming a side chain type liquid crystal polymer, or a discotic liquid crystal compound, and can be polymerized by irradiation with active energy rays. Compounds. Examples of the liquid crystal compound having a polymerizable group include JP-A-11-513360, JP-A-2002-030042, JP-A-2004-204190, JP-A-2005-263789, and JP-A-2007-119415. Examples thereof include rod-like liquid crystal compounds having a polymerizable group described in JP-A No. 2007-186430. Moreover, as a side chain type liquid crystal polymer compound, the side chain type liquid crystal polymer compound etc. which are described in Unexamined-Japanese-Patent No. 2003-177242 are mentioned, for example. Further, examples of preferable liquid crystal compounds include “LC242” manufactured by BASF and the like. Specific examples of the discotic liquid crystalline compound include JP-A-8-50206, literature (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); Chemical Society of Japan. Ed., Quarterly Chemistry Review, No. 22, Chemistry of Liquid Crystals, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985) ); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)). A photopolymerizable liquid crystal compound may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

Among these, as the photopolymerizable liquid crystal compound, a reverse wavelength polymerizable liquid crystal compound is preferable. Here, the reverse wavelength polymerizable liquid crystal compound refers to a photopolymerizable liquid crystal compound in which, when a polymer is obtained, the obtained polymer exhibits reverse wavelength dispersion characteristics. Further, the reverse wavelength dispersion characteristics include in-plane retardation Re (450) at a wavelength of 450 nm, in-plane retardation Re (550) at a wavelength of 550 nm, and in-plane retardation Re (650) at a wavelength of 650 nm. The characteristic which satisfy | fills Formula (1) and Formula (2) is said.
Re (450) / Re (550) <1 (1)
Re (650) / Re (550)> 1 (2)
By using a reverse wavelength polymerizable liquid crystal compound as part or all of the photopolymerizable liquid crystal compound contained in the liquid crystal composition as a coating liquid, an optically anisotropic layer having reverse wavelength dispersion characteristics can be easily used as a cured layer. Can be obtained.

  As the reverse wavelength polymerizable liquid crystal compound, a compound containing a main chain mesogen and a side chain mesogen bonded to the main chain mesogen in the molecule of the reverse wavelength polymerizable liquid crystal compound can be used. In the state where the reverse wavelength polymerizable liquid crystal compound containing the main chain mesogen and the side chain mesogen is aligned, the side chain mesogen can be aligned in a direction different from the main chain mesogen. Therefore, in the polymer obtained by polymerizing the reverse wavelength polymerizable liquid crystal compound while maintaining such orientation, the main chain mesogen and the side chain mesogen can be oriented in different directions. In such a case, birefringence appears as the difference between the refractive index corresponding to the main chain mesogen and the refractive index corresponding to the side chain mesogen, and as a result, the reverse wavelength polymerizable liquid crystal compound and the polymer thereof have the reverse wavelength. Dispersion characteristics can be expressed. Therefore, an optically anisotropic layer having reverse wavelength dispersion characteristics can be obtained as a cured layer by using the reverse wavelength polymerizable liquid crystal compound.

As described above, the three-dimensional shape of the compound having the main chain mesogen and the side chain mesogen is a specific shape different from the three-dimensional shape of a general positive wavelength polymerizable liquid crystal compound. Here, the “positive wavelength polymerizable liquid crystal compound” is a polymerizable liquid crystal compound in which, when a polymer is obtained, the obtained polymer exhibits positive wavelength dispersion characteristics. Further, the positive wavelength dispersion characteristics include in-plane retardation Re (450) at a wavelength of 450 nm, in-plane retardation Re (550) at a wavelength of 550 nm, and in-plane retardation Re (650) at a wavelength of 650 nm. The characteristic which satisfy | fills Formula (3) and Formula (4) is said.
Re (450) / Re (550)> 1 (3)
Re (650) / Re (550) <1 (4)

  Examples of the reverse wavelength polymerizable liquid crystal compound include compounds represented by the following formula (I). Hereinafter, the compound represented by the formula (I) may be referred to as “compound (I)” as appropriate.

If reversed wavelength polymerizable liquid crystal compound is a compound (I), group ^{-Y 5 -A 4 -Y 3 -A 2} -Y 1 -A 1 -Y 2 -A 3 -Y 4 -A 5 -Y 6 - Becomes the main chain mesogen, and the group> A ¹ -C (Q ¹ ) = NN (A ^x ) A ^y becomes the side chain mesogen. The group A ¹ affects the properties of both main chain and side chain mesogens.

In the formula (I), Y ^{1 to} Y ⁸ are each independently a chemical single bond, —O—, —S—, —O—C (═O) —, —C (═O) —. O—, —O—C (═O) —O—, —NR ¹ —C (═O) —, —C (═O) —NR ¹ —, —O—C (═O) —NR ¹ —, —NR ¹ —C (═O) —O—, —NR ¹ —C (═O) —NR ¹ —, —O—NR ¹ —, or —NR ¹ —O— is represented.

Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Examples of the alkyl group having 1 to 6 carbon atoms of R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, An n-hexyl group etc. are mentioned.
R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the compound (I), Y ^{1 to} Y ⁸ are each independently a chemical single bond, —O—, —O—C (═O) —, —C (═O) —O—, or , —O—C (═O) —O— is preferable.

In the formula (I), G ¹ and G ² each independently represent a divalent aliphatic group having 1 to 20 carbon atoms, which may have a substituent.
Examples of the divalent aliphatic group having 1 to 20 carbon atoms include a divalent aliphatic group having a chain structure such as an alkylene group having 1 to 20 carbon atoms and an alkenylene group having 2 to 20 carbon atoms; And divalent aliphatic groups such as 3 to 20 cycloalkanediyl groups, 4 to 20 carbon cycloalkylene diyl groups, and 10 to 30 carbon divalent alicyclic fused ring groups.

Examples of the substituent for the divalent aliphatic group represented by G ¹ and G ² include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; methoxy group, ethoxy group, n-propoxy group, isopropoxy group , An n-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an n-hexyloxy group or the like, or an alkoxy group having 1 to 6 carbon atoms; Of these, a fluorine atom, a methoxy group, and an ethoxy group are preferable.

The aliphatic group includes one or more —O—, —S—, —O—C (═O) —, —C (═O) —O—, —O—C per one aliphatic group. Even if (═O) —O—, —NR ² —C (═O) —, —C (═O) —NR ² —, —NR ² —, or —C (═O) — are present. Good. However, the case where two or more of -O- or -S- are adjacent to each other is excluded. Here, R ² represents the same hydrogen atom or alkyl group having 1 to 6 carbon atoms as R ^1, and is preferably a hydrogen atom or a methyl group.
As the group intervening in the aliphatic group, —O—, —O—C (═O) —, —C (═O) —O—, and —C (═O) — are preferable.

Specific examples of the aliphatic group mediated by these groups include —CH ₂ —CH ₂ —O—CH ₂ —CH ₂ —, —CH ₂ —CH ₂ —S—CH ₂ —CH ₂ —, —CH _{2. -CH 2 -O-C (= O} ) -CH 2 -CH 2 -, - CH 2 -CH 2 -C (= O) -O-CH 2 -CH 2 -, - CH 2 -CH 2 -C ( ═O) —O—CH ₂ —, —CH ₂ —O—C (═O) —O—CH ₂ —CH ₂ —, —CH ₂ —CH ₂ —NR ² —C (═O) —CH ₂ — ^{_{CH 2 -, - CH 2 -CH}} 2 -C (= O) -NR 2 -CH 2 -, - CH 2 -NR 2 -CH 2 -CH 2 -, - CH 2 -C (= O) -CH 2 -Etc. are mentioned.

Among these, G ¹ and G ² are each independently an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, or the like, from the viewpoint of better expressing the desired effect of the present invention. A divalent aliphatic group having a chain structure is preferable, and a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, a decamethylene group [— (CH ₂ ) ₁₀ - a] and the like, more preferably an alkylene group having 1 to 12 carbon atoms, a tetramethylene group [- _{(CH 2) 4} -], hexamethylene group [- _{(CH 2) 6} -], octamethylene [- ( CH ₂ ) ₈ —] and decamethylene group [— (CH ₂ ) ₁₀ —] are particularly preferred.

In the formula (I), Z ¹ and Z ² each independently represent an alkenyl group having 2 to 10 carbon atoms which is unsubstituted or substituted with a halogen atom.
As carbon number of this alkenyl group, 2-6 are preferable. Examples of the halogen atom that is a substituent of the alkenyl group of Z ¹ and Z ² include a fluorine atom, a chlorine atom, a bromine atom, and the like, and a chlorine atom is preferable.

Specific examples of the alkenyl group having 2 to 10 carbon atoms of Z ¹ and Z ² include CH ₂ ═CH—, CH ₂ ═C (CH ₃ ) —, CH ₂ ═CH—CH ₂ —, CH ₃ —CH═. _{CH-, CH 2 = CH-CH} 2 -CH 2 -, CH 2 = C (CH 3) -CH 2 -CH 2 -, (CH 3) 2 C = CH-CH 2 -, (CH 3) 2 C ═CH—CH ₂ —CH ₂ —, CH ₂ ═C (Cl) —, CH ₂ ═C (CH ₃ ) —CH ₂ —, CH ₃ —CH═CH—CH ₂ — and the like.

Especially, from a viewpoint of expressing the desired effect of the present invention better, Z ¹ and Z ² are each independently CH ₂ = CH-, CH ₂ = C (CH ₃ )-, CH ₂ = _{C (Cl) -, CH 2} = CH-CH 2 -, CH 2 = C (CH 3) -CH 2 -, _{or, CH 2 = C (CH 3} ) -CH 2 -CH 2 - are preferred, CH ₂ ═CH—, CH ₂ ═C (CH ₃ ) —, or CH ₂ ═C (Cl) — is more preferable, and CH ₂ ═CH— is particularly preferable.

In the formula (I), A ^x represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. “Aromatic ring” means a cyclic structure having a broad sense of aromaticity according to the Huckle rule, that is, a cyclic conjugated structure having (4n + 2) π electrons, and sulfur, oxygen, typified by thiophene, furan, benzothiazole, etc. It means a cyclic structure in which a lone electron pair of a hetero atom such as nitrogen is involved in the π-electron system and exhibits aromaticity.

Of A ^x, having at least one aromatic ring is selected from the group consisting of an aromatic hydrocarbon ring and aromatic heterocyclic organic group having 2 to 30 carbon atoms may be those having a plurality of aromatic rings And having an aromatic hydrocarbon ring and an aromatic heterocycle.

  Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of the aromatic heterocyclic ring include monocyclic aromatic heterocyclic rings such as a pyrrole ring, a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a pyrazole ring, an imidazole ring, an oxazole ring, and a thiazole ring; Benzothiazole ring, benzoxazole ring, quinoline ring, phthalazine ring, benzimidazole ring, benzopyrazole ring, benzofuran ring, benzothiophene ring, thiazolopyridine ring, oxazolopyridine ring, thiazolopyrazine ring, oxazolopyrazine ring, thia And a condensed aromatic heterocycle such as a zolopyridazine ring, an oxazolopyridazine ring, a thiazolopyrimidine ring, and an oxazolopyrimidine ring.

The aromatic ring of A ^x may have a substituent. Examples of the substituent include halogen atoms such as fluorine atom and chlorine atom; cyano group; alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group and propyl group; and carbon number 2 such as vinyl group and allyl group. -6 alkenyl groups; C 1-6 halogenated alkyl groups such as trifluoromethyl groups; substituted amino groups such as dimethylamino groups; C 1-6 alkoxys such as methoxy groups, ethoxy groups, and isopropoxy groups group; a nitro group; a phenyl group, an aryl group such as phenyl or ^{naphthyl; -C (= O) -R 5} ; -C (= O) -OR 5; -SO 2 R 6; and the like. Here, R ⁵ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms, and R ⁶ is the same as R ⁴ described later. An alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group, or a 4-methylphenyl group is represented.

Further, the aromatic ring within A ^x, which may have a plurality of identical or different substituents, bonded two adjacent substituents together may form a ring. The ring formed may be a monocycle, a condensed polycycle, an unsaturated ring, or a saturated ring.
Furthermore, the “carbon number” of the organic group having 2 to 30 carbon atoms of A ^x means the total carbon number of the whole organic group not including the carbon atom of the substituent (the same applies to A ^y described later). .

Of A ^x, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and aromatic heterocyclic ring, examples of the organic group having 2 to 30 carbon atoms, for example, an aromatic hydrocarbon ring group, aromatic A heterocyclic group; an alkyl group having 3 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring group and an aromatic heterocyclic group; an aromatic hydrocarbon ring group and an aromatic heterocyclic ring An alkenyl group having 4 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of a group; having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring group and an aromatic heterocyclic group, An alkynyl group having 4 to 30 carbon atoms; and the like.

Preferred specific examples of A ^x are shown below. However, ^Ax is not limited to the following. In the following formulae, “-” represents a bond extending from any position of the ring (the same applies hereinafter).

  (1) Aromatic hydrocarbon ring group

  (2) Aromatic heterocyclic group

In the above formula, E represents NR ^6a , an oxygen atom or a sulfur atom. Here, R ^6a represents a hydrogen atom; or an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, or a propyl group.

In the above formula, X, Y and Z each independently represent NR ⁷ , oxygen atom, sulfur atom, —SO— or —SO ₂ — (provided that oxygen atom, sulfur atom, —SO—, -SO ₂ - is, unless the respective adjacent).. R ⁷ represents the same hydrogen atom as R ^6a ; or an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, or a propyl group.

(In the above formula, X represents the same meaning as described above.)
(3) An alkyl group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring group and an aromatic heterocyclic group

  (4) An alkenyl group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring group and an aromatic heterocyclic group

  (5) An alkynyl group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring group and an aromatic heterocyclic group

Among the A ^x as described above, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or is preferably an aromatic heterocyclic group having 4 to 30 carbon atoms, more preferably one of the groups shown below .

Further, A ^x is more preferably any of the groups shown below.

Ring within A ^x may have a substituent. Examples of the substituent include halogen atoms such as fluorine atom and chlorine atom; cyano group; alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group and propyl group; and carbon number 2 such as vinyl group and allyl group. -6 alkenyl groups; C 1-6 halogenated alkyl groups such as trifluoromethyl groups; substituted amino groups such as dimethylamino groups; C 1-6 alkoxys such as methoxy groups, ethoxy groups, and isopropoxy groups group; a nitro group; a phenyl group, an aryl group such as phenyl or ^{naphthyl; -C (= O) -R 8} ; -C (= O) -OR 8; -SO 2 R 6; and the like. Here, R ⁸ represents an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; or an aryl group having 6 to 14 carbon atoms such as a phenyl group. Among these, a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms are preferable.

Further, the ring of A ^x may have a plurality of the same or different substituents, and two adjacent substituents may be bonded together to form a ring. The ring formed may be a single ring or a condensed polycycle.
The “carbon number” of the organic group having 2 to 30 carbon atoms of A ^x means the total number of carbon atoms of the entire organic group not including the carbon atom of the substituent (the same applies to A ^y described later).

In the formula (I), A ^y is a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having from 3 to 12 carbon atoms which may have a substituent, which may have a substituent group an alkynyl group having a carbon number of ^{2~20, -C (= O) -R} 3, -SO 2 An organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of —R ⁴ , —C (═S) NH—R ⁹ , or an aromatic hydrocarbon ring and an aromatic heterocyclic ring; Represent. Here, R ³ has an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, and a substituent. Or a C3-C12 cycloalkyl group or a C5-C12 aromatic hydrocarbon group. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group, or a 4-methylphenyl group. R ⁹ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, and an optionally substituted carbon. The C3-C12 cycloalkyl group or the C5-C20 aromatic group which may have a substituent is represented.

Of A ^y, the alkyl group having 1 to 20 carbon atoms an alkyl group having 1 to 20 carbon atoms that may have a substituent, such as methyl group, ethyl group, n- propyl group, an isopropyl radical, n -Butyl group, isobutyl group, 1-methylpentyl group, 1-ethylpentyl group, sec-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n -Heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n -Heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, etc. are mentioned. The carbon number of the alkyl group having 1 to 20 carbon atoms which may have a substituent is preferably 1 to 12, and more preferably 4 to 10.

Examples of the alkenyl group having 2 to 20 carbon atoms that may have a substituent in A ^y include, for example, a vinyl group, a propenyl group, an isopropenyl group, a butenyl group, and an isobutenyl group. Pentenyl group, hexenyl group, heptenyl group, octenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group and the like. It is preferable that carbon number of the C2-C20 alkenyl group which may have a substituent is 2-12.

Of A ^y, a cycloalkyl group having 3 to 12 carbon atoms a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, A cyclooctyl group etc. are mentioned.

Of A ^y, the alkynyl group of 2 to 20 carbon alkynyl group having carbon atoms of 2 to 20 which may have a substituent, such as ethynyl group, propynyl group, 2-propynyl group (propargyl group), Butynyl, 2-butynyl, 3-butynyl, pentynyl, 2-pentynyl, hexynyl, 5-hexynyl, heptynyl, octynyl, 2-octynyl, nonanyl, decanyl, 7-decanyl Etc.

Examples of the substituent of the alkyl group having 1 to 20 carbon atoms that may have a substituent and the alkenyl group having 2 to 20 carbon atoms that may have a substituent of A ^y include, for example, a fluorine atom Halogen atom such as chlorine atom; cyano group; substituted amino group such as dimethylamino group; alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, butoxy group; methoxymethoxy group, methoxyethoxy group A C1-C12 alkoxy group substituted with a C1-C12 alkoxy group; a nitro group; an aryl group such as a phenyl group or a naphthyl group; a carbon number such as a cyclopropyl group, a cyclopentyl group, or a cyclohexyl group A cycloalkyl group having 3 to 8 carbon atoms; a cycloalkyloxy group having 3 to 8 carbon atoms such as a cyclopentyloxy group and a cyclohexyloxy group; A cyclic ether group having 2 to 12 carbon atoms such as a ru group, a tetrahydropyranyl group, a dioxolanyl group and a dioxanyl group; an aryloxy group having 6 to 14 carbon atoms such as a phenoxy group and a naphthoxy group; a trifluoromethyl group and pentafluoroethyl A fluoroalkoxy group having 1 to 12 carbon atoms in which at least one is substituted with a fluorine atom, such as a group, —CH ₂ CF ₃ ; benzofuryl group; benzopyranyl group; benzodioxolyl group; benzodioxanyl group; _{^{(= O) -R 7a; -C}} (= O) -OR 7a; -SO 2 R 8a; -SR 10; alkoxy groups having 1 to 12 carbon atoms which is substituted with ^{-SR 10;} hydroxyl; and the like . Here, R ^7a and R ¹⁰ are each independently an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or 6 to 12 carbon atoms. And R ^8a represents the same alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group, or a 4-methylphenyl group as in R ⁴ above. .

Examples of the substituent of the cycloalkyl group having 3 to 12 carbon atoms that may have a substituent for A ^y include, for example, a halogen atom such as a fluorine atom and a chlorine atom; a cyano group; a substituted amino group such as a dimethylamino group Groups: alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, and propyl groups; alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, and isopropoxy groups; nitro groups; phenyl groups, naphthyl groups, and the like A cycloalkyl group having 3 to 8 carbon atoms such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group; —C (═O) —R ^7a ; —C (═O) —OR ^7a ; —SO ₂ R ^8a A hydroxyl group; and the like. Here, R ^7a and R ^8a represent the same meaning as described above.

Examples of the substituent of the alkynyl group having 2 to 20 carbon atoms that may have a substituent of A ^y include, for example, an alkyl group having 1 to 20 carbon atoms that may have a substituent, and substitution. The same substituent as the substituent of the C2-C20 alkenyl group which may have a group is mentioned.

In the group of A ^y represented by —C (═O) —R ³ , R ³ may have a substituent, an alkyl group having 1 to 20 carbon atoms, or a substituent. It represents a good alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 5 to 12 carbon atoms. Specific examples of these include an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent of the above ^Ay. The thing similar to what was listed as an example of the C3-C12 cycloalkyl group which you may have is mentioned.

Of A ^y, in the group represented by _-SO 2 -R ^{4, R 4} is an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group, or a 4-methylphenyl group Represent. Specific examples of the alkyl group having 1 to 20 carbon atoms and the alkenyl group having 2 to 20 carbon atoms of R ⁴ include the alkyl group having 1 to 20 carbon atoms and the alkenyl group having 2 to 20 carbon atoms of the above ^Ay . Examples are the same as those listed.

Of A ^y, having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and aromatic heterocyclic ring, examples of the organic group having 2 to 30 carbon atoms, the same ones as exemplified in the A ^x Is mentioned.

Among these, as ^Ay , a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, and a substituent A cycloalkyl group having 3 to 12 carbon atoms which may have an alkynyl group having 2 to 20 carbon atoms which may have a substituent, —C (═O) —R ³ , —SO ₂ —R ⁴ or a group represented by an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring, preferably a hydrogen atom or a substituent. C1-C20 alkyl group which may have, C2-C20 alkenyl group which may have a substituent, C3-C12 cycloalkyl which may have a substituent Group, an optionally substituted alkynyl group having 2 to 20 carbon atoms, An aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent, an aromatic heterocyclic group having 3 to 9 carbon atoms which may have a substituent, -C (= O) -R ³ And a group represented by —SO ₂ —R ⁴ is more preferable. Here, R ³ and R ⁴ represent the same meaning as described above.

^Ay , an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, and an optionally substituted carbon As a substituent of the alkynyl group having 2 to 20 carbon atoms, a halogen atom, a cyano group, an alkoxy group having 1 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 12 carbon atoms, phenyl group, a cyclohexyl group, a cyclic ether group having 2 to 12 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, a hydroxyl group, benzodioxanyl group, phenylsulfonyl group, 4-methyl phenylsulfonyl group, a benzoyl group, ^{-SR 10} Is preferred. Here, R ¹⁰ represents the same meaning as described above.

^Ay has an optionally substituted cycloalkyl group having 3 to 12 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms, and a substituent. As the substituent of the aromatic heterocyclic group having 3 to 9 carbon atoms, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a cyano group are preferable.

A ^x and A ^y may be combined to form a ring. Examples of such a ring include an unsaturated heterocyclic ring having 4 to 30 carbon atoms and an unsaturated carbocyclic ring having 6 to 30 carbon atoms, which may have a substituent.

The unsaturated heterocyclic ring having 4 to 30 carbon atoms and the unsaturated carbocyclic ring having 6 to 30 carbon atoms are not particularly limited and may or may not have aromaticity.
Examples of the ring formed by combining A ^x and A ^y include the rings shown below. In addition, the ring shown below is the one in the formula (I).

  The part represented as is shown.

(In the formula, X, Y and Z have the same meaning as described above.)
Moreover, these rings may have a substituent. Such substituent groups include the same ones as exemplified as the substituents of the aromatic ring within A ^x.

The total number of π electrons contained in A ^x and A ^y is preferably 4 or more, more preferably 6 or more, preferably 24 or less, more preferably from the viewpoint of better expressing the desired effect of the present invention. 20 or less, particularly preferably 18 or less.

As a preferable combination of A ^x and A ^y ,
(Α) A ^x is an aromatic hydrocarbon group or aromatic heterocyclic group having 4 to 30 carbon atoms, A ^y is a hydrogen atom, a cycloalkyl group having 3 to 8 carbon atoms, (halogen atom, cyano group, An aromatic hydrocarbon group having 6 to 12 carbon atoms which may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 8 carbon atoms) as a substituent. , (Halogen atom, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, cyano group) which may have as a substituent a C 3-9 aromatic heterocyclic group or substituent An optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 1 to 20 carbon atoms, or an optionally substituted substituent having 2 to 20 carbon atoms. And the substituent is a halogen atom, a cyano group, or 1 to 2 carbon atoms. 0 alkoxy group, C1-C12 alkoxy group substituted with C1-C12 alkoxy group, phenyl group, cyclohexyl group, C2-C12 cyclic ether group, C6-C14 aryloxy group, a hydroxyl group, benzodioxanyl group, benzenesulfonyl group, the combination is either a benzoyl group, and -SR ^10, and,
(Β) A combination in which A ^x and A ^y together form an unsaturated heterocyclic ring or an unsaturated carbocyclic ring,
Is mentioned. Here, R ¹⁰ represents the same meaning as described above.

As a more preferable combination of ^Ax and ^Ay ,
(Γ) A ^x is any of the groups having the following structure, and A ^y is a hydrogen atom, a cycloalkyl group having 3 to 8 carbon atoms, (a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, carbon An aromatic hydrocarbon group having 6 to 12 carbon atoms which may have an alkoxy group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms as a substituent, (halogen atom, 1 to 6 carbon atoms) An alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cyano group) as an optionally substituted aromatic heterocyclic group having 3 to 9 carbon atoms or an optionally substituted carbon atom having 1 substituent. An -20 alkyl group, an optionally substituted alkenyl group having 1 to 20 carbon atoms, or an optionally substituted alkynyl group having 2 to 20 carbon atoms, wherein the substituent is , Halogen atom, cyano group, alkoxy group having 1 to 20 carbon atoms, carbon number C1-C12 alkoxy group substituted with 1-12 alkoxy group, phenyl group, cyclohexyl group, C2-C12 cyclic ether group, C6-C14 aryloxy group, hydroxyl group, benzodioxa group, a benzenesulfonyl group, a combination is either a benzoyl group, and -SR ^10. Here, R ¹⁰ represents the same meaning as described above.

(In the formula, X and Y have the same meaning as described above.)
As a particularly preferred combination of A ^x and A ^y ,
(Δ) A ^x is any of the groups having the following structure, and A ^y is a hydrogen atom, a cycloalkyl group having 3 to 8 carbon atoms, (a halogen atom, a cyano group, an alkyl group having 1 to 6 carbon atoms, carbon An aromatic hydrocarbon group having 6 to 12 carbon atoms which may have an alkoxy group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 8 carbon atoms as a substituent, (halogen atom, 1 to 6 carbon atoms) An alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cyano group) as an optionally substituted aromatic heterocyclic group having 3 to 9 carbon atoms or an optionally substituted carbon atom having 1 substituent. An -20 alkyl group, an optionally substituted alkenyl group having 1 to 20 carbon atoms, or an optionally substituted alkynyl group having 2 to 20 carbon atoms, wherein the substituent is , Halogen atom, cyano group, alkoxy group having 1 to 20 carbon atoms, carbon number C1-C12 alkoxy group substituted with 1-12 alkoxy group, phenyl group, cyclohexyl group, C2-C12 cyclic ether group, C6-C14 aryloxy group, hydroxyl group, benzodioxa group, a benzenesulfonyl group, a benzoyl group, and a combination of any of -SR ^10. In the following formula, X represents the same meaning as described above. Here, R ¹⁰ represents the same meaning as described above.

In the formula (I), A ¹ represents a trivalent aromatic group which may have a substituent. The trivalent aromatic group may be a trivalent carbocyclic aromatic group or a trivalent heterocyclic aromatic group. From the viewpoint of better expressing the desired effect of the present invention, a trivalent carbocyclic aromatic group is preferable, a trivalent benzene ring group or a trivalent naphthalene ring group is more preferable, and a trivalent represented by the following formula: The benzene ring group or trivalent naphthalene ring group is more preferable. In the following formula, the substituents Y ¹ and Y ² are described for convenience in order to clarify the bonding state (Y ¹ and Y ² represent the same meaning as described above, and the same applies hereinafter). .

Among these, the ^{A 1,} and more preferably a group represented by the formula (A11) ~ (A25) shown below, equation (A11), (A13), (A15), in (A19), (A23) Groups represented by formulas (A11) and (A23) are particularly preferred.

Of A ^1, as a trivalent substituent which may be possessed by the aromatic group, the same ones as exemplified as the substituents of the aromatic groups of the A ^X and the like. A ¹ preferably has no substituent.

In the formula (I), A ² and A ³ each independently represent a C 3-30 divalent alicyclic hydrocarbon group which may have a substituent. Examples of the divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms include a cycloalkanediyl group having 3 to 30 carbon atoms and a divalent alicyclic condensed ring group having 10 to 30 carbon atoms. .

  Examples of the cycloalkanediyl group having 3 to 30 carbon atoms include cyclopropanediyl group; cyclobutanediyl group such as cyclobutane-1,2-diyl group and cyclobutane-1,3-diyl group; cyclopentane-1,2- Cyclopentanediyl group such as diyl group, cyclopentane-1,3-diyl group; cyclohexanediyl group such as cyclohexane-1,2-diyl group, cyclohexane-1,3-diyl group, cyclohexane-1,4-diyl group Groups: cycloheptane-1,2-diyl group, cycloheptane-1,3-diyl group, cycloheptanediyl group such as cycloheptane-1,4-diyl group; cyclooctane-1,2-diyl group, cyclooctane Cyclooctane such as -1,3-diyl group, cyclooctane-1,4-diyl group, cyclooctane-1,5-diyl group, etc. Cyclodecane-1, 2-diyl group, cyclodecane-1,3-diyl group, cyclodecane-1,4-diyl group, cyclodecane-1,5-diyl group and the like; cyclododecane-1, Cyclododecanediyl groups such as 2-diyl group, cyclododecane-1,3-diyl group, cyclododecane-1,4-diyl group, cyclododecane-1,5-diyl group; cyclotetradecane-1,2-diyl group Cyclotetradecane-1,3-diyl group, cyclotetradecane-1,4-diyl group, cyclotetradecane-1,5-diyl group, cyclotetradecane-1,7-diyl group and the like; cycloeicosane -1,2-diyl group, cycloeicosanediyl group such as cycloeicosane-1,10-diyl group; and the like.

  Examples of the divalent alicyclic fused ring group having 10 to 30 carbon atoms include decalindiyl groups such as decalin-2,5-diyl group and decalin-2,7-diyl group; adamantane-1,2-diyl group An adamantanediyl group such as an adamantane-1,3-diyl group; a bicyclo [2.2.1] heptane-2,3-diyl group, a bicyclo [2.2.1] heptane-2,5-diyl group Bicyclo [2.2.1] heptanediyl group such as bicyclo [2.2.1] heptane-2,6-diyl group; and the like.

These divalent alicyclic hydrocarbon groups may have a substituent at any position. Examples of the substituent, the same ones as exemplified as the substituents of the aromatic groups of the A ^X and the like.

Among these, the ^{A 2} and ^{A 3,} preferably a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, more preferably a cycloalkane-diyl group having 3 to 12 carbon atoms, following formula (A31) ~ (A34)

Is more preferable, and the group represented by the formula (A32) is particularly preferable.
The divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms is a cis type or a trans type based on the difference in configuration of carbon atoms bonded to Y ¹ , Y ³ (or Y ² , Y ⁴ ). Stereoisomers can exist. For example, in the case of a cyclohexane-1,4-diyl group, as shown below, a cis-type isomer (A32a) and a trans-type isomer (A32b) may exist.

  The divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms may be cis, trans, or a mixture of cis and trans isomers. From the viewpoint of good orientation, the trans type or cis type is preferable, and the trans type is more preferable.

In the formula (I), A ⁴ and A ⁵ each independently represent a C 6-30 divalent aromatic group which may have a substituent. The aromatic groups of A ⁴ and A ⁵ may be monocyclic or polycyclic. Preferable specific examples of A ⁴ and A ⁵ include the following.

The divalent aromatic groups of A ⁴ and A ⁵ may have a substituent at any position. Examples of the substituent include a halogen atom, a cyano group, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, and a —C (═O) —OR ^8b group; Is mentioned. Here, R ^8b is an alkyl group having 1 to 6 carbon atoms. Especially, a halogen atom, a C1-C6 alkyl group, and an alkoxy group are preferable. Further, a fluorine atom is more preferable as the halogen atom, a methyl group, an ethyl group, and a propyl group are more preferable as the alkyl group having 1 to 6 carbon atoms, and a methoxy group and an ethoxy group are more preferable as the alkoxy group.

Among these, from the viewpoint of better expressing the desired effect of the present invention, A ⁴ and A ⁵ may each independently have a substituent, and the following formulas (A41) and (A42) And a group represented by (A43) is more preferred, and a group represented by formula (A41) which may have a substituent is particularly preferred.

In the formula (I), Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. The optionally substituted alkyl group having 1 to 6 carbon atoms, the same ones as exemplified in the A ^X and the like. Among these, Q ¹ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a methyl group.

  Compound (I) can be produced, for example, by a reaction of a hydrazine compound and a carbonyl compound described in International Publication No. 2012/147904.

The liquid crystal composition as the coating liquid may contain any component in combination with the above-described photopolymerizable liquid crystal compound. For example, the liquid crystal composition can include a polymerizable monomer. The “polymerizable monomer” refers to a compound other than a reverse wavelength polymerizable liquid crystal compound, among compounds having a polymerization ability and capable of functioning as a monomer. As the polymerizable monomer, for example, one having one or more polymerizable groups per molecule can be used. By having such a polymerizable group, polymerization can be achieved in forming the optically anisotropic layer. When the polymerizable monomer is a crosslinkable monomer having two or more polymerizable groups per molecule, crosslinkable polymerization can be achieved. Examples of the polymerizable group include the same groups as the groups Z ¹ -Y ⁷ -and Z ² -Y ^8- in the compound (I), and more specifically, for example, an acryloyl group and a methacryloyl group. Groups and epoxy groups.

  The polymerizable monomer itself may be liquid crystalline or non-liquid crystalline. Here, “non-liquid crystalline” per se means that the polymerizable monomer itself is aligned on a base film having an alignment regulating force even when placed at any temperature from room temperature to 200 ° C. This means something not shown. Whether or not the orientation is indicated is determined by whether or not there is a contrast between light and dark when the rubbing direction is rotated by the surface phase in the crossed Nicol transmission observation of the polarizing microscope.

The ratio of the polymerizable monomer is preferably 1 part by weight to 100 parts by weight, and more preferably 5 parts by weight to 50 parts by weight with respect to 100 parts by weight of the reverse wavelength polymerizable liquid crystal compound. Within the above range, precise control of the reverse wavelength dispersion characteristic is facilitated by appropriately adjusting the ratio of the polymerizable monomer so as to exhibit the desired reverse wavelength dispersion characteristic.
The polymerizable monomer can be produced by a known production method. Or what has a structure similar to compound (I) can be manufactured according to the manufacturing method of compound (I).

  The liquid crystal composition as the coating liquid may contain a photopolymerization initiator. As a photoinitiator, it can select suitably according to the kind of polymeric group which the polymeric compound in a liquid-crystal composition has. For example, a radical polymerization initiator can be used if the polymerizable group is radical polymerizable, an anionic polymerization initiator can be used if it is an anion polymerizable group, and a cationic polymerization initiator can be used if it is a cationic polymerizable group. .

  Examples of the radical polymerization initiator include a photo radical generator that is a compound that generates an active species capable of initiating polymerization of a polymerizable compound by light irradiation.

  Examples of the photoradical generator include acetophenone compounds, biimidazole compounds, triazine compounds, O-acyloxime compounds, onium salt compounds, benzoin compounds described in International Publication No. 2012/147904, Examples include benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, diazo compounds, and imide sulfonate compounds.

  Examples of the anionic polymerization initiator include alkyl lithium compounds; monolithium salts or monosodium salts such as biphenyl, naphthalene, and pyrene; polyfunctional initiators such as dilithium salts and trilithium salts; and the like.

  Examples of the cationic polymerization initiator include proton acids such as sulfuric acid, phosphoric acid, perchloric acid, and trifluoromethanesulfonic acid; Lewis acids such as boron trifluoride, aluminum chloride, titanium tetrachloride, and tin tetrachloride. An aromatic onium salt or a combination system of an aromatic onium salt and a reducing agent.

  Specific examples of commercially available photopolymerization initiators include trade name: Irgacure 907, trade name: Irgacure 184, trade name: Irgacure 369, trade name: Irgacure 651, trade name: Irgacure 819, trade name: Irgacure 907, product, manufactured by BASF Name: Irgacure 379, trade name: Irgacure 379EG, and trade name: Irgacure OXE02; trade name: Adekaoptomer N1919, manufactured by ADEKA, and the like.

  One type of these photopolymerization initiators may be used alone, or two or more types may be used in combination at any ratio.

  The ratio of the photopolymerization initiator is preferably 0.1 part by weight to 30 parts by weight, more preferably 0.5 part by weight to 10 parts by weight with respect to 100 parts by weight of the polymerizable compound.

  The liquid crystal composition as the coating liquid may contain a surfactant for adjusting the surface tension. The surfactant is not particularly limited, but a nonionic surfactant is preferable. A commercially available product can be used as the nonionic surfactant. For example, a nonionic surfactant that is an oligomer having a molecular weight of about several thousand can be used. Specific examples of these surfactants include “PF-151N”, “PF-636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-3320” of PolyFox, OMNOVA. "PF-651", "PF-652"; Neos's Fantent's "FTX-209F", "FTX-208G", "FTX-204D", "601AD"; Seimi Chemical's Surflon "KH-40" , “S-420” or the like can be used. Moreover, surfactant may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. The ratio of the surfactant is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 2 parts by weight, with respect to 100 parts by weight of the polymerizable compound.

  The liquid crystal composition as the coating liquid may contain a solvent such as an organic solvent. Examples of such organic solvents include hydrocarbon solvents such as cyclopentane and cyclohexane; ketone solvents such as cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, and methyl isobutyl ketone; acetate solvents such as butyl acetate and amyl acetate; chloroform, dichloromethane Halogenated hydrocarbon solvents such as dichloroethane; ether solvents such as 1,4-dioxane, cyclopentylmethyl ether, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,2-dimethoxyethane; aromatics such as toluene, xylene, mesitylene Group hydrocarbon solvents; and mixtures thereof. The boiling point of the solvent is preferably 60 ° C. to 250 ° C., more preferably 60 ° C. to 150 ° C., from the viewpoint of excellent handleability. The amount of the solvent used is preferably 100 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the polymerizable compound.

  The liquid crystal composition as a coating liquid further comprises metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixotropic agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers, antioxidants. An optional additive such as an agent, an ion exchange resin, and a metal oxide such as titanium oxide may be included. The ratio of such optional additives is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable compound.

  A pre-curing layer is obtained by coating the coating liquid on the base film. The coating is usually performed by applying a coating solution on one surface of a long base film that is continuously conveyed. Examples of coating methods include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating, and die coating. Method, cap coating method, and dipping method. The thickness of the pre-curing layer to be formed can be appropriately set according to the desired thickness required for the cured layer.

  When the coating liquid is applied onto the base film, an appropriate tension (usually 100 N / m to 500 N / m) is applied to the base film to reduce the fluttering of the base film and maintain the flatness. It is preferable to apply as it is. The flatness is a shake amount in the vertical direction perpendicular to the width direction and the conveyance direction of the base film, ideally 0 mm, but usually 1 mm or less.

[5. Orientation process]
Prior to the step of heating the base film, an alignment treatment may be applied as needed to promote the alignment of the photopolymerizable liquid crystal compound contained in the pre-curing layer. The alignment may be achieved immediately by application of the liquid crystal composition, but may also be achieved by performing an alignment treatment such as heating. The alignment treatment conditions can be appropriately set according to the properties of the liquid crystal composition to be used. For example, the alignment treatment can be performed at a temperature of 50 ° C. to 160 ° C. for 30 seconds to 5 minutes.

[6. Drying process]
Before the step of heating the base film, a step of drying the pre-curing layer may be performed as necessary. Such drying can be achieved by a drying method such as natural drying, heat drying, reduced pressure drying, and reduced pressure heat drying. By such drying, the solvent can be removed from the pre-curing layer.

[7. Preheating process]
FIG. 1 is a front view schematically showing a manufacturing apparatus 20 used in a method for manufacturing an optical film 10 according to an embodiment of the present invention.
As shown in FIG. 1, in the manufacturing method of the optical film 10 according to this embodiment, after preparing the multilayer film 50 including the base film 30 and the pre-curing layer 40 as described above, the multilayer film 50 is prepared. The process of heating 50 base film 30 is performed. When the base film 30 is heated, the pre-curing layer 40 provided on the base film 30 is also usually heated. In this embodiment, the multilayer film 50 is supplied to the oven 100 as a heating device by continuously transporting the multilayer film 50 in the longitudinal direction while maintaining the flatness, and the base film 30 is heated by the oven 100. An example will be described.

  FIG. 2 is a plan view schematically showing the base film 30 used in the method for manufacturing the optical film 10 according to one embodiment of the present invention. The heating of the base film 30 is performed in a state where an effective portion of the base film 30 is in the air. Here, the effective part of the base film 30 is a part of the base film 30 corresponding to the product part of the optical film 10. Usually, in the elongate optical film 10, the both ends of the width direction are cut off and the intermediate part except the both ends of the width direction is used as a product. Therefore, the effective portion of the base film 30 usually corresponds to an intermediate portion 31 excluding both end portions 32 and 33 in the width direction of the base film 30 as shown in FIG. Therefore, in the following description, the effective portion of the base film 30 is described with the reference numeral “31” common to the intermediate portion 31 of the base film 30.

  Moreover, the state in which the part of the base film 30 is in the air means a state in which a manufacturing facility such as a roll or an oven is not in contact with the part of the base film 30. Therefore, in a state where the effective portion 31 of the base film 30 is in the air, the effective portion 31 does not contact the manufacturing facility. On the other hand, in the process in which the base film 30 is heated, the portions other than the effective portion 31 of the base film 30 such as both end portions 32 and 33 may be in the air and the manufacturing equipment is not in contact with each other. The manufacturing equipment may be in contact. In the present embodiment, an example will be described in which the base film 30 is heated by the oven 100 in a state where the entire width direction of the base film 30 including the effective portion 31 and both end portions 32 and 33 is in the air. .

The base film 30 is heated so that the heated base film 30 has a predetermined preheating temperature T _base . The preheating temperature T _base is higher than the room temperature of the room in which the manufacturing apparatus 20 is installed, and among these, it is preferable that the following formula (i) is satisfied with respect to the temperature T _br of the back roll 200.
T _base −T _br > −5 ° C. (i)

The formula (i) will be described in more detail. The preheating temperature T _base is preferably higher than “T _br −5 ° C.”, more preferably higher than “T _br −3 ° C.”, and particularly preferably “T _br −1”. Higher than ℃ ”. Before the base film 30 comes into contact with the back roll 200, the base film 30 is heated to the preheating temperature T _base as described above, whereby wrinkles in the base film 30 when coming into contact with the back roll 200 are obtained. Generation | occurrence | production can be suppressed and, therefore, the hardened layer with a favorable surface state can be obtained. From the viewpoint of suppressing deformation of the base film 30, the upper limit of the preheating temperature T _base is preferably equal to or lower than the glass transition temperature of the resin included in the base film 30.

Since the base film 30 is thin, it normally reaches the set temperature of the heating device quickly when heated by the heating device. Therefore, normally, the preset temperature of the heating device can be the preheating temperature T _{base of the base} film 30 heated by the heating device.

The multilayer film 50 including the base film 30 heated to the preheating temperature T _base by the oven 100 is conveyed toward the back roll 200 as shown in FIG. At this time, the multilayer film 50 is transported so that the temperature of the _base film 30 is not greatly reduced from the preheating temperature T _base after being heated in the oven 100 and before contacting the back roll 200. Is preferred. Specifically, the temperature drop is caused by the expansion stress that may be generated by the temperature difference between the base film 30 and the back roll 200 at the time when the base film 30 starts to contact the back roll 200. It is preferable to keep it in a small range so that it can be weakened so as not to cause wrinkles. Thus, in order to reduce the temperature drop, the oven 100 is preferably provided immediately before the back roll 200 in the film conveyance path. Here, in the film conveyance path, the position of the oven 100 immediately before the back roll 200 means that a member (such as a conveyance roll) that contacts the multilayer film 50 in the film conveyance path between the oven 100 and the back roll 200. Indicates that there is no. Thereby, the temperature fall of the base film 30 by contact can be suppressed. The distance between the oven 100 and the back roll 200 is preferably close. Thereby, the temperature fall of the base film 30 by heat dissipation can be suppressed.

At the time when the base film 30 and the back roll 200 start to contact, the base film 30 preferably has a preheating temperature T _base that satisfies the above-described formula (i). Therefore, as described above, when the temperature of the base film 30 decreases after being heated in the oven 100 until it contacts the back roll 200, the oven 100 is heated to a higher temperature by the temperature decrease. It is preferable to heat the base film 30 by.

[8. Step of curing the pre-curing layer]
A back roll 200 is provided downstream of the oven 100 in the film conveyance path. The back roll 200 is a roll that can support the base film 30 from the side opposite to the pre-curing layer 40 when the active energy ray 310 is irradiated.

  The back roll 200 rotates in the same direction as the transport direction of the multilayer film 50 as indicated by an arrow A200. When the multilayer film 50 is conveyed to the back roll 200, the multilayer film 50 is supported and conveyed at the position L with the base film 30 in contact with the peripheral surface 210 of the back roll 200. .

  In this position L, the pre-curing layer 40 of the multilayer film 50 is irradiated with the active energy ray 310 from the irradiation device 300, whereby the pre-curing layer 40 is cured to obtain the cured layer 60. Usually, the irradiation of the active energy ray 310 causes a reaction such as polymerization or crosslinking of the monomer component contained in the pre-curing layer 40. Therefore, the pre-curing layer 40 is cured by irradiation with the active energy ray 310. In the case where the pre-curing layer 40 includes a photopolymerizable liquid crystal compound as in the example shown in the present embodiment, the photopolymerizable liquid crystal compound is polymerized while maintaining its orientation. A layer is obtained.

The step of curing the pre-curing layer 40 as described above is performed by adjusting the temperature _Tbr of the back roll 200 to a predetermined range. Specifically, the temperature T _br of the back roll 200 is usually 30 ° C. or higher, preferably 35 ° C. or higher, more preferably 40 ° C. or higher. By increasing the temperature T _br of the back roll 200 as described above, the reaction of the monomer component contained in the pre-curing layer 40 is promoted, so that a cured layer 60 having a low residual monomer component ratio is obtained. Here, the residual monomer component ratio refers to the ratio of the monomer component contained in the cured layer 60. From the viewpoint of preventing deformation of the base film 30, the upper limit of the temperature T _br of the back roll 200 is preferably equal to or lower than the glass transition temperature of the resin included in the base film 30.

The irradiation intensity of the active energy ray 310 is preferably set in an appropriate range so that the pre-curing layer 40 can be sufficiently cured. For example, when using ultraviolet rays as the active energy ray 310, ultraviolet ray irradiation intensity is preferably ^{0.1mW / cm 2 ~1000mW / cm 2} , more preferably at ^{0.5mW / cm 2 ~600mW / cm 2} . The ultraviolet irradiation time is preferably 1 second to 300 seconds, more preferably 5 seconds to 100 seconds. The integrated light quantity (mJ / cm ² ) of ultraviolet rays can be obtained by ultraviolet irradiation intensity (mW / cm ² ) × irradiation time (seconds). As the ultraviolet light source, for example, a light source such as a high pressure mercury lamp, a metal halide lamp, a low pressure mercury lamp, or a UV-LED can be used.

  Irradiation of the active energy ray 310 to the pre-curing layer 40 tends to reduce the residual monomer component ratio when performed under an inert gas atmosphere such as a nitrogen atmosphere rather than under air. Therefore, it is preferable to irradiate the active energy ray 310 to the pre-curing layer 40 in such an inert gas atmosphere.

  By the above-described step of curing the pre-curing layer 40, a cured layer 60 having a good surface state is obtained. According to the study of the present inventors, the reason why the cured layer 60 having a good surface state can be obtained by the manufacturing method according to the present embodiment is presumed as follows. However, the technical scope of the present invention is not limited by the following inference.

FIGS. 3 and 4 illustrate a multilayer film 940 in which the base film 920 is brought into contact with the peripheral surface 930 of the back roll 910 without heating the base film 920 before contacting the back roll 910. It is sectional drawing which shows typically the cross section cut by the plane perpendicular | vertical to the conveyance direction of 940. FIG.
As shown in FIG. 3, it is assumed that the base film 920 is brought into contact with the peripheral surface 930 of the back roll 910 without heating the base film 920. In this case, when the temperature of the back roll 910 is higher than room temperature, the base film 920 is heated by the base film 920 coming into contact with the peripheral surface 930 of the back roll 910. In the heated base film 920, as shown by an arrow A10, an expansion stress is generated due to thermal expansion. Therefore, the base film 920 tends to extend in the in-plane direction.

  However, since the base film 920 is usually easy to grip on the peripheral surface 930 of the back roll 910, there is a large friction between the base film 920 and the peripheral surface 930 of the back roll 910 as shown by the arrow A20. Power is generated. This frictional force restrains the base film 920 and prevents the base film 920 from stretching due to the expansion stress. As a result, the base film 920 cannot eliminate the expansion stress due to the stretch.

  Due to the expansion stress that could not be eliminated in this way, as shown in FIG. 4, the base film 920 is deformed so as to bend in the thickness direction. And by the deformation | transformation to this thickness direction, the base film 920 may produce the wrinkle extended in the conveyance direction. When such wrinkles occur in the base film 920, the pre-curing layer 950 provided on the base film 920 is affected, and thus a planar failure occurs in the cured layer obtained by curing the pre-curing layer 950. It was.

  On the other hand, in the manufacturing method according to the present embodiment, the base film 30 was heated before contacting the back roll 200 as shown in FIG. Therefore, even if the base film 30 comes into contact with the back roll 200, the base film 30 is unlikely to have a large expansion stress that causes wrinkles. Therefore, since wrinkles in the base film 30 supported in a state in contact with the peripheral surface 210 of the back roll 200 can be suppressed, the surface failure of the cured layer 60 can be suppressed, and as a result, the surface state of the cured layer 60 can be changed. Can be good.

  Furthermore, in the manufacturing method according to this embodiment, the base film 30 is heated by the oven 100 in a state where the whole width direction of the base film 30 including the effective portion 31 is in the air. Therefore, since the base film 30 is not restrained by frictional force during heating, the base film 30 is unlikely to be wrinkled even by heating with the oven 100. Therefore, according to the manufacturing method according to the present embodiment, the surface state of the cured layer 60 can be made particularly favorable.

[9. Optical film]
By curing the pre-curing layer 40 of the multilayer film 50, the optical film 10 including the base film 30 and the cured layer 60 can be obtained. In the manufacturing method according to the present embodiment, since the long base film 30 is used, the optical film 10 is also obtained as a long film.

In the hardened layer 60 of the optical film 10, planar failures are suppressed. Therefore, the surface state of the hardened layer 60 is good. Here, the surface state of the hardened layer 60 can be evaluated by the following method.
On the surface light source device, the first linear polarizing plate, the optical film and the second linear polarizing plate are placed, and the surface light source device, the first linear polarizing plate, the base film, the cured layer, and the second straight line. An evaluation system including a polarizing plate in this order is prepared. At this time, the positional relationship between the polarization transmission axis of the first linearly polarizing plate and the polarization transmission axis of the second linearly polarizing plate was detected as a planar failure according to the retardation of the base film and the cured layer. Set to an appropriate position that is easy to use. Then, the surface state of a hardened layer can be evaluated by making a surface light source device emit light and observing an optical film from various directions.

  In the cured layer 60, the residual monomer component ratio is usually small. The specific residual monomer component ratio of the cured layer 60 is preferably 25% by weight or less, more preferably 20% by weight or less, still more preferably 10% by weight or less, and particularly preferably 6% by weight or less. The lower limit of the residual monomer component ratio is ideally 0% by weight, but can be 2% by weight or more. Such a small ratio of residual monomer components in the cured layer 60 indicates that reactions such as polymerization and crosslinking have advanced to a high degree. Therefore, since the said hardened layer 60 has the outstanding mechanical strength, it can have high durability. Further, particularly when the cured layer 60 is an optically anisotropic layer as in this embodiment, the cured layer 60 is brought into contact with the adhesive by reducing the residual monomer component ratio of the cured layer 60 in this way. Moreover, the change of the in-plane retardation of the hardened layer 60 can be suppressed.

  The residual monomer component ratio of the cured layer 60 can be obtained by extracting the monomer component from the cured layer to obtain an extraction solution, and quantifying the amount of the monomer component in the extraction solution. The quantification of the monomer component in the extraction solution can be performed by a quantification method such as gas chromatography.

  The cured layer 60 is preferably peelable from the base film 30. Moreover, it is preferable that the hardened layer 60 can be transferred to another member. Thereby, since it becomes possible to exhibit the optical characteristic of the hardened layer 60, without being influenced by the base film 30, the hardened layer 60 can be used for a wide range of applications. In particular, the cured layer 60 has a suppressed change in in-plane retardation when brought into contact with the adhesive as described above. The optical characteristics can be exhibited stably.

  The thickness of the cured layer 60 can be arbitrarily set according to the use of the optical film 10. The specific thickness is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less.

  Further, when the optical film 10 including the optically anisotropic layer is manufactured as the cured layer 60 as in the present embodiment, the optically anisotropic layer usually includes cured liquid crystal molecules obtained from a photopolymerizable liquid crystal compound. . The “cured liquid crystal molecule” means a molecule of the compound when a compound capable of exhibiting a liquid crystal phase is turned into a solid while exhibiting a liquid crystal phase. The cured liquid crystal molecules contained in the optically anisotropic layer are usually polymers obtained by polymerizing a photopolymerizable liquid crystal compound.

  In the optically anisotropic layer, the cured liquid crystal molecules may preferably have an alignment regularity that is horizontally aligned with respect to the base film. Here, when the cured liquid crystal molecules are “horizontally aligned” with respect to the base film, the average direction of the major axis direction of the mesogen of the cured liquid crystal molecules is parallel or nearly parallel to the film surface (for example, the angle formed with the film surface Alignment in a certain direction within 5 °). Whether or not the cured liquid crystal molecules are horizontally aligned and the alignment direction thereof can be confirmed by measurement using a phase difference meter such as AxoScan (manufactured by Axometrics).

  Here, when the cured liquid crystal molecule is obtained by polymerizing a photopolymerizable liquid crystal compound having a rod-like molecular structure, the major axis direction of the mesogen of the photopolymerizable liquid crystal compound is usually the cured liquid crystal molecule. The long axis direction of the mesogen. In addition, when a plurality of types of mesogens having different orientation directions are present in the optically anisotropic layer as in the case of using the reverse wavelength dispersion photopolymerizable liquid crystal compound as the photopolymerizable liquid crystal compound, the most The direction in which the long axis directions of long types of mesogens are aligned is the alignment direction.

  The optically anisotropic layer preferably has reverse wavelength dispersion characteristics. An optically anisotropic layer having reverse wavelength dispersion characteristics usually exhibits large in-plane retardation for transmitted light having a longer wavelength than a short wavelength. Therefore, since the optically anisotropic layer has reverse wavelength dispersion characteristics, the optically anisotropic layer can uniformly function in a wide wavelength band in an optical application such as a λ / 4 wavelength plate or a λ / 2 wavelength plate. .

  Since the optically anisotropic layer has optical anisotropy, it causes retardation in light transmitted through the optically anisotropic layer. In a preferred embodiment, the optically anisotropic layer is a λ / 4 wavelength plate or a λ / 2 wavelength plate. Specifically, when the in-plane retardation Re measured at a measurement wavelength of 550 nm is in the range of 108 nm to 168 nm, the optically anisotropic layer can be used as a λ / 4 wavelength plate. When the in-plane retardation Re measured at a measurement wavelength of 550 nm is in the range of 245 nm to 305 nm, the optically anisotropic layer can be used as a λ / 2 wavelength plate. More specifically, in the case of a λ / 4 wavelength plate, the in-plane retardation Re measured at a measurement wavelength of 550 nm is preferably 110 to 170 nm (that is, 140 ± 30 nm), more preferably 128 nm to 148 nm, and still more preferably. It is in the range of 135 nm to 145 nm (ie 140 ± 5 nm). In the case of a λ / 2 wavelength plate, the in-plane retardation Re measured at a measurement wavelength of 550 nm is preferably in the range of 265 nm to 285 nm, more preferably 270 nm to 280 nm. When the optically anisotropic layer is such a λ / 4 wavelength plate or λ / 2 wavelength plate, an optical element such as a circularly polarizing plate having a λ / 4 wavelength plate or a λ / 2 wavelength plate is used. The device can be easily manufactured.

  The angle formed by the slow axis of the optically anisotropic layer and the width direction of the optically anisotropic layer can be the same as the angle formed by the direction of the orientation regulating force of the base film 30 and the width direction of the base film 30. . Specifically, when the base film 30 is a diagonally stretched film and has an orientation regulating force along the stretch direction, the slow axis of the optically anisotropic layer and the width direction of the optically anisotropic layer form. Specifically, the angle may be greater than 0 ° and less than 90 °. In one embodiment, the angle formed by the slow axis of the optically anisotropic layer and the width direction of the optically anisotropic layer is preferably 15 ° ± 5 °, 22.5 ° ± 5 °, 45 ° ± 5. Or 75 ° ± 5 °, more preferably 15 ° ± 4 °, 22.5 ° ± 4 °, 45 ° ± 4 °, or 75 ° ± 4 °, even more preferably 15 ° ± 3 °, 22 It can be a specific range such as 5 ° ± 3 °, 45 ° ± 3 °, or 75 ° ± 3 °. By having such an angular relationship, the optical film 10 can be a material that enables efficient production of a circularly polarizing plate.

[10. Modified example]
Although one embodiment of the present invention has been described above, the present invention can be further modified and implemented.
For example, in the above-described embodiment, the optically anisotropic layer is formed as the cured layer 60. However, when the cured layer 60 other than the optically anisotropic layer is produced, the method for producing the optical film of the present invention is applied. Also good. Examples of the cured layer 60 other than the optically anisotropic layer include a hard coat layer, an antireflection layer, an antistatic layer, an antiglare layer, and an easy adhesion layer.

  Moreover, the manufacturing method of the optical film 10 may include processes other than those described above. For example, the method for manufacturing the optical film 10 may include a step of forming an arbitrary layer on the cured layer 60. Examples of the optional layer include an adhesive layer for adhering to other members, a mat layer for improving the slipperiness of the film, a hard coat layer, an antireflection layer, and an antifouling layer.

  Furthermore, an apparatus other than the oven 100 may be used as the heating apparatus.

  Moreover, in embodiment mentioned above, although the heating of the base film 30 in the oven 100 was performed in the state in which the whole width direction of the base film 30 is in the air, the said heating is an effective part of the base film 30. You may carry out in the state which manufacturing equipment contacted parts other than 31. FIG. For example, the both ends 32 and 33 (see FIG. 2) in the width direction of the base film 30 are pulled with a tenter device, and heating is performed while applying a tension in the film width direction that is weak enough to prevent the base film 30 from being stretched. You may go. Thus, even when it heats in the state which manufacturing equipment contacted parts other than the effective part 31 of the base film 30, in the product part of the optical film 10, make the surface state of the hardened layer 60 favorable. Is possible.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples described below, and does not depart from the scope of the claims of the present invention and the equivalents thereof. It may be carried out by arbitrarily changing in. In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.

[Evaluation method]
[Measurement method of tensile modulus in width direction of film]
A rectangular test piece (length 250 mm × width 10 mm) having a long side parallel to the width direction of the film was cut out from the film. Based on JIS K7113, the stress at the time of straining the test piece by pulling it in the long side direction was measured using a tensile tester with a constant temperature and humidity chamber (5564 type digital material tester manufactured by Instron Japan) at a temperature of 23. The measurement was performed under the conditions of ° C., humidity 60 ± 5% RH, distance between chucks 115 mm, and tensile speed 100 mm / min. Such a measurement was performed three times. Then, from the measured stress and the measurement data of the strain corresponding to the stress, the measurement data (that is, the strain is 0.1%) in the range of 0.6% to 1.2% of the strain of the test piece. 6%, 0.8%, 1.0%, and 1.2% measured data), and the tensile modulus of the film is calculated from the selected 3 measured data using the least squares method. did.

[Measurement method of residual monomer component ratio of cured layer]
The photopolymerizable liquid crystal compounds used in Examples and Comparative Examples were dissolved in a solvent (1,3-dioxolane) to obtain solutions for preparing calibration curves with various concentrations. These solutions were subjected to HPLC to prepare a calibration curve.

  A portion of 10 cm × 10 cm of the cured layer was scraped off with a spatula from the optical film obtained in each example and comparative example, and weighed into a vial. Furthermore, 1 g of a solvent (1,3-dioxolane) was added, allowed to stand for 24 hours, and filtered through a 0.45 μm filter to extract unreacted monomer components, thereby obtaining an extract. The obtained extract was analyzed by HPLC, and the residual monomer component ratio was determined by comparing the measurement result with a calibration curve.

The HPLC conditions were as follows.
Column: LC1200 (manufactured by Agilent Technologies)
Column temperature: 40 ° C
Carrier (water: acetonitrile)
Linear concentration gradient from 0 min (water: acetonitrile = 5: 95) to 5 min (water: acetonitrile = 0: 100), then 25 min (water: acetonitrile = 0: 100)
Outflow time of residual monomer component: around 13.2 min

[Evaluation method of surface state of hardened layer]
On the surface light source device, the first linear polarizing plate, the optical film and the second linear polarizing plate are placed, and the surface light source device, the first linear polarizing plate, the base film, the cured layer, and the second straight line. An evaluation system provided with polarizing plates in this order was prepared. At this time, the positional relationship between the polarization transmission axis of the first linear polarizing plate and the polarization transmission axis of the second linear polarizing plate was set to be parallel (paranicol) when viewed from the thickness direction.

In the evaluation system, the surface light source device was caused to emit light, the optical film was observed from various directions, and the surface state of the cured layer of the optical film was determined according to the following criteria.
Good: No surface failure is observed.
Defect: A planar failure with deformation of the base film was observed.

[Production Example 1. Manufacturing of coating liquid]
100 parts of a photopolymerizable liquid crystal compound (B1) having a structure represented by the following formula (B1), 3 parts of a photopolymerization initiator (“Irgacure 379EG” manufactured by BASF), and a surfactant (“Furgent” manufactured by Neos) 601AD ") 0.3 parts, and dilute solvent (cyclopentanone: 1,3-dioxolane = 1: 1) was added so that the solid content was 22%, and the mixture was heated to 50 ° C and dissolved. I let you. The obtained mixture was filtered through a 0.45 μm membrane filter to produce a liquid crystal composition as a coating solution.

[Example 1]
As a base film, a long diagonally stretched film made of a resin containing an alicyclic structure-containing polymer (“Zeonor Film ZD Series” manufactured by Nippon Zeon Co., Ltd., glass transition temperature of 126 ° C., thickness of 47 μm, wavelength of 550 nm) An in-plane retardation of 141 nm and a stretching direction of 45 ° with respect to the width direction were prepared. On this base film, the liquid crystal composition obtained in Production Example 1 was applied by a die to form a liquid crystal composition layer as a pre-curing layer. The thickness of the pre-curing layer was adjusted so that the thickness of the resulting cured layer was about 2.3 μm. This obtained the multilayer film provided with a base film and a layer before hardening.

  Then, it was dried in a 110 ° C. oven for about 2 minutes to evaporate the solvent in the pre-curing layer, and at the same time, the photopolymerizable liquid crystal compound contained in the pre-curing layer was oriented in the stretching direction of the base film.

Then, as shown in FIG. 1, the multilayer film 50 was conveyed so that it might pass through the oven 100 provided just before the back roll 200, and the base film 30 of the multilayer film 50 was heated. The heating by the oven 100 was performed in a state where the base film 30 was in the air by preventing any member from coming into contact with the multilayer film 50. In addition, during the heating, the temperature of the oven 100 was set to the preheating temperature T _base shown in Table 1 so that the base film 30 immediately after heating was adjusted to the preheating temperature T _base .

After the heating, the multilayer film 50 was immediately transported to the back roll 200 having the temperature T _br shown in Table 1. And the ultraviolet-ray was irradiated to the layer 40 before hardening of the multilayer film 50 with the ultraviolet irradiation device, conveying the base film 30 in the state closely_contact | adhered to the back roll 200. FIG. Irradiation was performed in a nitrogen atmosphere. By polymerizing the photopolymerizable liquid crystal compound, the pre-curing layer 40 was cured, and an optically anisotropic layer was obtained as the cured layer 60. Thus, the optical film 10 provided with the base film 30 and the cured layer 60 was manufactured.
Thereafter, the obtained optical film 10 was evaluated by the method described above.

[Example 2]
By changing the temperature of the oven, the preheating temperature T _base of the _base film immediately after being heated in the oven was changed as shown in Table 1. Except for the above, the optical film was produced and evaluated in the same manner as in Example 1.

[Example 3]
The base film is made of a resin containing an alicyclic structure-containing polymer, and is a long obliquely stretched film (“ZEONOR FILM ZD series” manufactured by ZEON Corporation, resin glass transition temperature 126 ° C., thickness 23 μm, wavelength 550 nm. The in-plane retardation was 141 nm, and the stretching direction was changed to 45 ° with respect to the width direction. Further, by changing the temperature of the oven, the preheating temperature T _base of the _base film immediately after being heated in the oven was changed as shown in Table 1. Except for the above, the optical film was produced and evaluated in the same manner as in Example 1.

[Comparative Examples 1 and 2]
The substrate film was not heated in the oven. Further, the temperature Tbr of the back roll was changed as shown in Table 1. Except for the above, the optical film was produced and evaluated in the same manner as in Example 1.

[result]
The results of the examples and comparative examples are shown in Table 1 below. In Table 1, Tbase of Comparative Example 1 and Comparative Example 2 indicates the temperature of the base film immediately before contacting the back roll. This temperature was measured using a measuring machine (“Data Logger NR-600” manufactured by Keyence Corporation) with a thermocouple attached to the base film. In Table 1, the meanings of the abbreviations are as follows.
T _base : The temperature (preheating temperature) of the base film immediately after heating by the oven.
T _br : temperature of the back roll.
Substrate thickness: The thickness of the substrate film.
Elastic modulus: The tensile elastic modulus in the width direction of the base film.

[Consideration]
As shown in Comparative Example 1, when the temperature T _br of the back roll is close to room temperature, no planar failure occurs in the cured layer, but the residual monomer component ratio in the cured layer increases. On the other hand, when the temperature T _{br of the} back roll is high, the ratio of residual monomer components in the cured layer can be reduced, but wrinkles occur in the base film that contacts the back roll, resulting in a planar failure in the cured layer. It was.
On the other hand, in Examples 1-3, the base film is heated to a temperature close to the temperature T _{br of the} back roll immediately before the base film comes into contact with the high temperature back roll. Thereby, since the wrinkle did not arise in the base film which contacted the back roll, the planar failure in the hardened layer could be suppressed.
From the above results, according to the production method of the present invention, it was confirmed that an optical film including a cured layer having a good surface state can be produced using a high-temperature back roll.

DESCRIPTION OF SYMBOLS 10 Optical film 20 Manufacturing apparatus 30 Base film 31 Effective part (intermediate part) of base film
32 and 33 End of base film 40 Pre-curing layer 50 Multi-layer film 60 Cured layer 100 Oven 200 Back roll 210 Back roll peripheral surface 300 Irradiation device 310 Active energy ray

Claims (4)

A method for producing an optical film comprising a long base film and a cured layer,
Heating the base film of a multilayer film comprising the base film and a pre-curing layer that can be cured by active energy rays, with an effective portion of the base film in the air; and
A process of obtaining the cured layer by curing the pre-cured layer by irradiating the pre-cured layer with active energy rays in a state where the heated base film is in contact with a back roll of 30 ° C. or higher. And a method for producing an optical film. The manufacturing method of the optical film of Claim 1 with which temperature _Tbase of the said _base film heated and temperature _Tbr of the said back roll satisfy | fill following formula (i).
T _base −T _br > −5 ° C. (i) The tensile elastic modulus in the width direction of the base film is 2500 MPa or less,
The manufacturing method of the optical film of Claim 1 or 2 whose thickness of the said base film is 50 micrometers or less.   The manufacturing method of the optical film as described in any one of Claims 1-3 in which the said hardened layer can be peeled from the said base film, or it can transfer to another member.

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