JP4953876B2 - Optical film manufacturing method, optical film, polarizing plate, and liquid crystal display device - Google Patents

Description

  The present invention relates to a method for producing an optical film used for optical compensation or the like of a liquid crystal display device. Moreover, this invention relates to the optical film manufactured by this method, a polarizing plate using the same, and a liquid crystal display device.

Various optical films having an optically anisotropic layer formed by applying and drying a liquid crystal composition coating liquid have been proposed as optical films used for optical compensation of liquid crystal display devices. About these optical films, there exists a request | requirement about making the thickness of the whole film thin, and the manufacturing method which responds to this request | requirement is proposed (for example, patent document 1).
JP 2004-226945 A

However, when the present inventors actually manufactured an optical film by the method described in Patent Document 1, depending on the material used, the transparency of the manufactured optical film is lowered and may not be used as an optical compensation film. It turned out to be.
It is an object of the present invention to provide a method capable of stably producing an optical film having an optically anisotropic layer formed using a liquid crystal composition with a thin thickness and without failure such as opacity. And
Another object of the present invention is to provide an optical film having a good optical compensation ability, a polarizing plate and a liquid crystal display device having a good performance by using such a production method.

  As a result of intensive studies by the present inventors, when the alignment film is actively used as an optical anisotropic layer contributing to the optical compensation ability, a material different from the conventional alignment film, a different formation method, or a different treatment is used. It is necessary to apply. As such, when an optically anisotropic layer made of a liquid crystal composition is formed by applying a liquid crystal composition coating liquid of a conventional formulation to an alignment film different from the conventional one, the surface of the alignment film becomes clouded by the coating liquid. As a result, the inventors have found that the transparency is lowered and the film cannot be used as an optical compensation film. As a result of further diligent studies based on this knowledge, the solvent used for preparing the coating liquid of the liquid crystal composition used when forming the optically anisotropic layer made of the liquid crystal composition, and functioning as an alignment film and optical When a predetermined relationship is established with a layer that also functions as an anisotropic layer, white turbidity does not occur and an optical film can be stably produced, thereby completing the present invention. It came to.

Means for solving the above problems are as follows.
[1] A step of preparing a coating solution by dissolving and / or dispersing at least a liquid crystal compound in a solvent, and coating the coating solution on the surface of the first optically anisotropic layer containing a non-liquid crystalline polymer, A method for producing an optical film comprising at least a step of forming a second optical anisotropic layer on the layer,
The solvent used for the preparation of the coating solution is selected from the solvents satisfying the following formulas (1) and (2) when only the solvent is applied to the surface of the first optical anisotropic layer. Characteristic optical film manufacturing method:
(1): ΔRe (550) ≦ 5 nm
(2): ΔRth (550) ≦ 10 nm
However, ΔRe (550) is the difference between the in-plane retardation Re (550) at a wavelength of 550 nm before and after applying the solvent to the first optical anisotropic layer, and ΔRth (550) is the first optical difference. This is the difference in the thickness direction retardation Rth (550) at a wavelength of 550 nm before and after applying the solvent to the isotropic layer.
[2] The method includes a step of applying any one of a stretching process, a shrinking process, and a rubbing process to the first optically anisotropic layer before applying the coating solution [1] the method of.
[3] The method according to [1] or [2], wherein the solvent is toluene or xylene.
[4] The method according to any one of [1] to [3], wherein the non-liquid crystalline polymer is polyimide.
[5] The method according to any one of [1] to [3], wherein the non-liquid crystalline polymer is polyvinyl alcohol or modified polyvinyl alcohol having a polymerization degree of 1000 to 5000.
[6] The method according to any one of [1] to [5], wherein the support is a film containing cellulose acylate.
[7] The method according to any one of [1] to [5], wherein the support is a film containing a cycloolefin polymer.
[8] After coating the coating liquid on the surface of the first optically anisotropic layer, the liquid crystal compound molecules in the coating film are aligned, the alignment state is fixed, and the second optically anisotropic layer is formed. The method according to any one of [1] to [7], wherein
[9] Forming the second optically anisotropic layer by fixing the molecules of the liquid crystal compound in any one of a homogeneous alignment, homeotropic alignment, hybrid alignment, twist alignment, and tilt alignment. The method of [8] characterized.
[10] The method according to any one of [1] to [9], wherein the liquid crystal compound is at least one selected from a liquid crystal polymer, a photopolymerizable liquid crystal monomer, and a thermally polymerizable liquid crystal monomer.
[11] An optical film having the first and second optically anisotropic layers produced by the method according to any one of [1] to [10]:
[12] The optical film of [11], wherein the optical characteristics of the first optically anisotropic layer satisfy the following formulas (VII) to (X).
(VII): −10 nm ≦ Re (550) ≦ 10 nm
(VIII): 0 nm ≦ Rth (550) ≦ 200 nm
(IX): −10 nm ≦ Re (630) −Re (450) ≦ 0 nm
(X): −40 nm ≦ Rth (630) −Rth (450) ≦ 0 nm
In the above formulas (VII) to (X), Re (λ) is an in-plane retardation value at a wavelength λnm, and Rth (λ) is a retardation value in the thickness direction at a wavelength λnm.
[13] It further includes a support that supports the first and second optically anisotropic layers, and the optical properties of the support satisfy the following formulas (I) to (VI) [11] ] Or [12] optical film:
(I): 0 nm ≦ Re (550) ≦ 200 nm
(II): 0 nm ≦ Rth (550) ≦ 300 nm
(III): 0 nm ≦ Re (630) −Re (450) ≦ 30 nm
(IV): 0 nm ≦ Rth (630) −Rth (450) ≦ 40 nm
(V): 0 nm ≦ Re (10% RH) −Re (80% RH) ≦ 20 nm
(VI): 0 nm ≦ Rth (10% RH) −Rth (80% RH) ≦ 30 nm
However, in the above formulas (I) to (IV), Re (λ) is an in-plane retardation value at a wavelength λnm, and Rth (λ) is a retardation value in the thickness direction at a wavelength λnm, In the above formulas (V) and (VI), Re (α% RH) is an in-plane retardation value in which the moisture content has reached an equilibrium state at an ambient humidity of 25 ° C. and α% RH, and Rth (α% (RHλ) is a retardation value in the thickness direction in which the moisture content has reached an equilibrium state at an ambient humidity of 25 ° C. and α% RH.
[14] A polarizing plate comprising at least a polarizing film and the optical film of any one of [11] to [13].
[15] A liquid crystal display device comprising the polarizing plate of [14].
[16] The liquid crystal display device according to [15], wherein the liquid crystal cell is a TN, OCB, VA, or IPS system.

According to the present invention, there is provided a method capable of stably producing an optical film having an optically anisotropic layer formed using a liquid crystal composition with a thin thickness and without failure such as opacity. Can do.
Further, according to the present invention, it is possible to provide an optical film having a good optical compensation ability, a polarizing plate and a liquid crystal display device having a good performance by using such a manufacturing method.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the present specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light is incident at a wavelength of λ nm from the inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction of the rotation axis of KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (10) and (11).

式中、上記のＲｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値をあらわす。
また式中、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘ及びｎｙに直交する方向の屈折率を表し、ｄは膜厚（μｍ）を表す。

In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction.
In the formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, nz represents the refractive index in the direction orthogonal to nx and ny, d represents a film thickness (μm).

When the film to be measured is a film that cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is from −50 degrees to +50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) and the tilt axis (rotating axis). In each of the 10 degree steps, light of wavelength λ nm is incident from the inclined direction and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or WR is calculated.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.
Further, in this specification, unless a measurement wavelength is particularly added, it is assumed that Re and Rth are at a wavelength of 550 nm.

In the present invention, at least a liquid crystal compound is dissolved and / or dispersed in a solvent to prepare a coating solution, and the coating solution is applied to the surface of the first optically anisotropic layer containing a non-liquid crystalline polymer. And an optical film manufacturing method including at least a step of forming a second optically anisotropic layer on the layer. In the present invention, the solvent used for the preparation of the coating solution is selected from solvents that satisfy the following formulas (1) and (2) when only the solvent is applied to the surface of the first optically anisotropic layer. It is characterized by being.
(1): ΔRe (550) ≦ 5 nm
(2): ΔRth (550) ≦ 10 nm
However, ΔRe (550) is the difference in in-plane retardation Re (550) at a wavelength of 550 nm before and after applying the solvent to the first optical anisotropic layer, and ΔRth (550) is the first optical This is the difference in the thickness direction retardation Rth (550) at a wavelength of 550 nm before and after applying the solvent to the anisotropic layer.
By selecting a material that satisfies this relationship, the first optical anisotropy functions as an alignment film for the second optical anisotropic layer and exhibits sufficient optical anisotropy that contributes to the optical compensation capability. The second optical anisotropic layer can be stably formed on the surface of the layer without causing a failure such as cloudiness.

Hereafter, each process and the material used for it are demonstrated in detail.
[Formation of first optically anisotropic layer]
The first optically anisotropic layer is preferably formed by applying and drying a coating liquid of a non-liquid crystalline polymer composition on the surface of a polymer film or the like. The polymer composition contains a non-liquid crystalline polymer that can exhibit optical anisotropy and can exhibit liquid crystal alignment ability (including those that are expressed by post-treatment such as rubbing treatment). Contains one or more. Although there is no restriction | limiting in particular about the polymer used for formation of the said 1st optically anisotropic layer, From a viewpoint that an optically anisotropic polymer layer can be formed by application | coating, polyvinyl alcohol, polyimide, polyolefin (example, Polyethylene, polypropylene, norbornene polymers), polycarbonate, polyarylate, polysulfone, polyvinyl alcohol, polymethacrylate, polyacrylate, cellulose ester (eg, cellulose triacetate, cellulose diacetate), polyamide, polyester, polyether Preference is given to at least one polymer material selected from the group consisting of ketones, polyamideimide polyesterimides, and polyaryletherketones. Among these, a polymer selected from the group consisting of polyimide, polyetherketone, polyamideimide, and polyesterimide is preferable. Further, polyvinyl alcohol having a predetermined polymerization degree and saponification degree, which will be described later, is also preferable. When a polymer layer is formed by coating using a predetermined polyvinyl alcohol and polyimide, Rth is expressed in the polymer layer, and the Rth exhibits forward dispersion wavelength dependency. Preferred optical characteristics are shown.

(Polyimide)
There is no restriction | limiting in particular about the polyimide used for formation of the said 1st optically anisotropic layer. It can be selected from various known polyimides. Examples of preferable polyimide include polyimides described in JP-A-2004-226945, [0011] to [0034]. More specifically, polyimide having high in-plane orientation and soluble in an organic solvent is preferable. Specifically, for example, it includes a condensation polymerization product of 9,9-bis (aminoaryl) fluorene and an aromatic tetracarboxylic dianhydride disclosed in JP 2000-511296 A, and has the following formula ( A polymer containing one or more repeating units shown in 1) can be used.

In the formula (1), R ³ to R ⁶ are hydrogen, halogen, a phenyl group, 1-4 halogen atoms, or C ₁ ~ ₁₀ alkyl-substituted phenyl, and C ₁ ~ ₁₀ alkyl group And at least one substituent selected independently from the group. Preferably, R ³ to R ⁶ is a halogen, a phenyl group, each independently from the group consisting of one to four halogen atoms or C ₁ ~ ₁₀ alkyl-substituted phenyl, and C ₁ ~ ₁₀ alkyl group It is at least one type of substituent selected.

In the formula (1), Z represents a tetravalent aromatic group C ₆ ~ _20, preferably a pyromellitic group, a polycyclic aromatic group, a derivative of a polycyclic aromatic group, or, It is group represented by following formula (2).

In the formula (2), Z ′ is, for example, a covalent bond, C (R ⁷ ) ₂ group, CO group, O atom, S atom, SO ₂ group, Si (C ₂ H ₅ ) ₂ group, or NR ^{There are 8} groups, and when there are multiple groups, they are the same or different. W represents an integer of 1 to 10. Each R ⁷ is independently hydrogen or C (R ⁹ ) ₃ . R ⁸ is hydrogen, an alkyl group or a C ₆ ~ ₂₀ aryl group, the carbon atom number from 1 to about 20, for a plurality, it may be the same or different. Each R ⁹ is independently hydrogen, fluorine, or chlorine.

Examples of the polycyclic aromatic group include a tetravalent group derived from naphthalene, fluorene, benzofluorene or anthracene. The substitution Examples of the substituted derivatives of polycyclic aromatic group, for example, an alkyl group of C ₁ ~ _10, at least one group selected from the group consisting of fluorinated derivatives, and F or a halogen such as Cl And the above-mentioned polycyclic aromatic group.

  In addition, for example, a homopolymer described in JP-A-8-511812, wherein the repeating unit is represented by the following general formula (3) or (4), or the repeating unit is represented by the following general formula (5): The polyimide etc. which are shown are mentioned. In addition, the polyimide of following formula (5) is a preferable form of the homopolymer of following formula (3).

In the general formulas (3) to (5), G and G ′ are, for example, a covalent bond, a CH ₂ group, a C (CH ₃ ) ₂ group, a C (CF ₃ ) ₂ group, or a C (CX ₃ ) ₂ group. (Wherein X is halogen), from the group consisting of CO group, O atom, S atom, SO ₂ group, Si (CH ₂ CH ₃ ) ₂ group, and N (CH ₃ ) group, respectively It represents independently selected groups, and may be the same or different.

In the above formulas (3) and (5), L is a substituent, and d and e represent the number of substitutions. L is, for example, a halogen, a C _1-3 alkyl group, a C _1-3 halogenated alkyl group, a phenyl group, or a substituted phenyl group, and in a plurality of cases, they are the same or different. Examples of the substituted phenyl group include substituted phenyl groups having at least one type of substituent selected from the group consisting of halogen, C _1-3 alkyl groups, and C _1-3 halogenated alkyl groups. Examples of the halogen include fluorine, chlorine, bromine, and iodine. d is an integer from 0 to 2, and e is an integer from 0 to 3.

  In the formulas (3) to (5), Q is a substituent, and f represents the number of substitutions. Q is, for example, selected from the group consisting of hydrogen, halogen, alkyl group, substituted alkyl group, nitro group, cyano group, thioalkyl group, alkoxy group, aryl group, substituted aryl group, alkyl ester group, and substituted alkyl ester group And when Q is plural, they are the same or different. Examples of the halogen include fluorine, chlorine, bromine and iodine. Examples of the substituted alkyl group include a halogenated alkyl group. Examples of the substituted aryl group include a halogenated aryl group. f is an integer from 0 to 4, and g and h are integers from 0 to 3 and from 1 to 3, respectively. Further, g and h are preferably larger than 1.

In the formula (4), R ¹⁰ and R ¹¹ are groups independently selected from the group consisting of hydrogen, halogen, phenyl group, substituted phenyl group, alkyl group, and substituted alkyl group. Among these, R ¹⁰ and R ¹¹ are preferably each independently a halogenated alkyl group.

In the formula (5), M ¹ and M ² are the same or different and are, for example, halogen, C _1-3 alkyl group, C _1-3 halogenated alkyl group, phenyl group, or substituted phenyl group. is there. Examples of the halogen include fluorine, chlorine, bromine and iodine. Examples of the substituted phenyl group include substituted phenyl groups having at least one type of substituent selected from the group consisting of halogen, C _1-3 alkyl groups, and C _1-3 halogenated alkyl groups. .

  Specific examples of the polyimide represented by the formula (3) include those represented by the following formula (6).

  Furthermore, examples of the polyimide include a copolymer obtained by appropriately copolymerizing an acid dianhydride other than the skeleton (repeating unit) as described above and a diamine.

  As said acid dianhydride, aromatic tetracarboxylic dianhydride is mentioned, for example. Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, heterocyclic aromatic tetracarboxylic dianhydride, 2, 2'-substituted biphenyltetracarboxylic dianhydride and the like.

  Examples of the pyromellitic dianhydride include pyromellitic dianhydride, 3,6-diphenylpyromellitic dianhydride, 3,6-bis (trifluoromethyl) pyromellitic dianhydride, and 3,6-dibromo. Examples include pyromellitic dianhydride and 3,6-dichloropyromellitic dianhydride. Examples of the benzophenone tetracarboxylic dianhydride include 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2 , 2 ′, 3,3′-benzophenone tetracarboxylic dianhydride and the like. Examples of the naphthalenetetracarboxylic dianhydride include 2,3,6,7-naphthalene-tetracarboxylic dianhydride, 1,2,5,6-naphthalene-tetracarboxylic dianhydride, 2,6 -Dichloro-naphthalene-1,4,5,8-tetracarboxylic dianhydride and the like. Examples of the heterocyclic aromatic tetracarboxylic dianhydride include thiophene-2,3,4,5-tetracarboxylic dianhydride and pyrazine-2,3,5,6-tetracarboxylic dianhydride. Pyridine-2,3,5,6-tetracarboxylic dianhydride and the like. Examples of the 2,2′-substituted biphenyltetracarboxylic dianhydride include 2,2′-dibromo-4,4 ′, 5,5′-biphenyltetracarboxylic dianhydride and 2,2′-dichloro. -4,4 ', 5,5'-biphenyltetracarboxylic dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride, etc. Can be mentioned.

  Other examples of the aromatic tetracarboxylic dianhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and bis (2,3-dicarboxyphenyl) methane dianhydride. Bis (2,5,6-trifluoro-3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3 3-hexafluoropropane dianhydride, 4,4′-bis (3,4-dicarboxyphenyl) -2,2-diphenylpropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4′-oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 4,4 ′ -[4,4′-isopropyl Den-di (p-phenyleneoxy)] bis (phthalic anhydride), N, N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl) Examples include diethylsilane dianhydride.

  Among these, the aromatic tetracarboxylic dianhydride is preferably 2,2′-substituted biphenyltetracarboxylic dianhydride, more preferably 2,2′-bis (trihalomethyl) -4,4. ', 5,5'-biphenyltetracarboxylic dianhydride, more preferably 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride It is.

  Examples of the diamine include aromatic diamines, and specific examples include benzene diamine, diaminobenzophenone, naphthalene diamine, heterocyclic aromatic diamine, and other aromatic diamines.

  Examples of the benzenediamine include o-, m- and p-phenylenediamine, 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 1,4-diamino-2-phenylbenzene, and 1, Examples include diamines selected from the group consisting of benzenediamines such as 3-diamino-4-chlorobenzene. Examples of the diaminobenzophenone include 2,2′-diaminobenzophenone and 3,3′-diaminobenzophenone. Examples of the naphthalenediamine include 1,8-diaminonaphthalene and 1,5-diaminonaphthalene. Examples of the heterocyclic aromatic diamine include 2,6-diaminopyridine, 2,4-diaminopyridine, and 2,4-diamino-S-triazine.

  In addition to these, the aromatic diamine includes 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 4,4 ′-(9-fluorenylidene) -dianiline, 2,2′-bis ( Trifluoromethyl) -4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2′-dichloro-4,4′-diaminobiphenyl, 2,2 ′, 5 5′-tetrachlorobenzidine, 2,2-bis (4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) -1,1, 1,3,3,3-hexafluoropropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-amino) Phenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3 -Hexafluoropropane, 4,4'-diaminodiphenyl thioether, 4,4'-diaminodiphenyl sulfone and the like.

  Although the molecular weight of the polymer is not particularly limited, for example, the weight average molecular weight (Mw) is preferably in the range of 1,000 to 1,000,000, more preferably in the range of 2,000 to 500,000. is there. The weight average molecular weight is a value measured by gel permeation chromatography (GPC) using polyethylene oxide as a standard sample and using a dimethylformamide solvent.

(Polyvinyl alcohol)
The polymer material for forming the first optically anisotropic layer is preferably polyvinyl alcohol. The hydroxyl group in the polyvinyl alcohol may be partially modified (hereinafter referred to as “polyvinyl alcohol” in the sense of including “modified polyvinyl alcohol”). Moreover, it is preferable that the average degree of polymerization of polyvinyl alcohol used for formation of a 1st optically anisotropic layer is 1000-5000. The average degree of polymerization is more preferably 1200 to 5000, and further preferably 1700 to 5000.
Further, the saponification degree of polyvinyl alcohol is preferably 80 to 100%, more preferably 95 to 100%.
That is, in order to form a first optically anisotropic layer that functions as an alignment film and satisfies sufficient optical properties that contribute to optical compensation, polyvinyl alcohol having a polymerization degree of 1000 to 5000 and modified polyvinyl alcohol are used. It is preferable to use at least one polymer material selected from the group consisting of at least one polymer selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol having a polymerization degree in the above range and a saponification degree of 80% to 100%. It is more preferable to use a material.

  Commercially available polyvinyl alcohol may be used. Examples of unmodified polyvinyl alcohol having a polymerization degree in the above range include PVA117, PVA124, PVA135, PVA217 manufactured by Kuraray Co., Ltd., JF17, JP25, JP18 manufactured by Nihon Vineyards Bipoval, etc. Can be used.

  In addition to the polyvinyl alcohol, other polymers may be used. Examples of polymers other than polyvinyl alcohol that can be added include, for example, methacrylate polymers, styrene polymers, polyolefins, poly (N-methylolacrylamide) described in paragraph No. [0022] of JP-A-8-338913. Polyester, polyimide, vinyl acetate polymer, carboxymethyl cellulose, polycarbonate, gelatin, silane coupling agent and the like.

  Further, modified polyvinyl alcohol may be used. The modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. Specific examples of these modified polyvinyl alcohol compounds include those described in paragraph numbers [0022] to [0145] of JP-A No. 2000-155216 and paragraph numbers [0018] to [0022] of JP-A No. 2002-62426, for example. Etc.

  If desired, a polymer having a crosslinkable functional group may be added. The crosslinkable functional group preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] of JP-A No. 2000-155216.

Polyvinyl alcohol can be cross-linked using a cross-linking agent separately from the cross-linkable functional group.
Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to the said polyvinyl alcohol, and, as for the addition amount of the said crosslinking agent, 0.5-15 mass% is more preferable. The amount of the remaining unreacted crosslinking agent is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

  A polymer composition used for forming the first optically anisotropic layer may be prepared as a coating solution. The coating liquid can be prepared by dissolving and / or dispersing a liquid crystal material or a polymer material in a solvent. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

  The coating method used for forming the first optically anisotropic layer is not particularly limited, and is a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating). Law). Especially, it is preferable to apply using a wire bar coating method. In addition, a die coating method is also preferably used for forming the second optically anisotropic layer, and in particular, a coating method using a slide coater or a slot die coater can also be preferably used.

Before applying the coating liquid for the second optically anisotropic layer, before applying the coating liquid, any one of a stretching process, a shrinking process, and a rubbing process is applied to the first optically anisotropic layer. It is preferable to perform the process. These treatments are performed in order to impart a distribution effect and / or impart desired optical properties to the first optically anisotropic layer.
As the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of the LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing using a cloth in which fibers having a uniform length and thickness are flocked on average.

  The stretching treatment and the shrinking treatment are preferably performed on the entire laminate after forming the first optically anisotropic layer on a support such as a polymer film to produce a laminate. A preferable polymer film used for the support will be described later. The conditions for the stretching treatment and the shrinking treatment are not particularly limited, and can be determined according to the optical characteristics required for the first optical anisotropic layer. It may be performed under any conditions such as uniaxial longitudinal / lateral stretching, biaxial stretching, longitudinal or lateral stretching, and lateral or longitudinal shrinkage.

  The thickness of the first optically anisotropic layer is not particularly limited, and the thickness can be determined so as to satisfy the optical characteristics required for the first optically anisotropic layer. The preferable range differs depending on the material. For example, when the first optical anisotropic layer is formed using polyimide, the thickness is preferably 0.5 to 20 μm, and 0.8 to 5. The thickness is more preferably 0 μm, and when formed using polyvinyl alcohol, the thickness is preferably 0.5 to 50 μm, and more preferably 0.5 to 20 μm.

(Formation of second optically anisotropic layer)
In the present invention, the second optically anisotropic layer is prepared by dissolving and / or dispersing at least a liquid crystal compound in a solvent to prepare a coating liquid, and the coating liquid is applied to the surface of the first optically anisotropic layer. Apply and form. The solvent used for preparing the coating solution is selected from solvents that satisfy the following formulas (1) and (2) when only the solvent is applied to the surface of the first optically anisotropic layer.
(1): ΔRe (550) ≦ 5 nm
(2): ΔRth (550) ≦ 10 nm
ΔRe (550) is more preferably 3 nm or less, and ΔRth (550) is further preferably 5 nm or less.

The solvent species used for the preparation of the second optically anisotropic layer-forming coating solution is determined in relation to the non-liquid crystal polymer material that is the material for forming the first optically anisotropic layer. When polyimide is used as the material for forming the first optically anisotropic layer, it is preferable to use an aromatic solvent as the solvent, and among these, toluene or xylene is preferable .

The second coating liquid for forming an optically anisotropic layer contains at least one liquid crystalline compound. The liquid crystalline compound may be a polymer liquid crystal or a low molecular liquid crystal. In order to form a layer, it is preferably a liquid crystal polymer or a polymerizable liquid crystal monomer capable of forming a layer by curing. The polymerizable liquid crystal monomer is preferably selected from a photopolymerizable liquid crystal monomer and a thermally polymerizable liquid crystal monomer. The type of the liquid crystalline compound is not particularly limited, and may be any of a rod-like liquid crystal whose molecule shape is a rod shape and a disk-like liquid crystal whose molecule shape is a disc shape.
In addition, in the coating liquid, a polymerization system that contributes to the curing of the liquid crystal composition, a polymerization system such as a polymerizable monomer, an alignment regulator that contributes to form a desired alignment state, and a liquid crystal composition You may add surfactant etc. which contribute to improvement of applicability | paintability.

  When the coating solution contains a polymerization additive, after coating the coating solution on the surface of the first optical anisotropic layer, the molecules of the liquid crystal compound in the coating film are aligned, and the alignment state is changed. The second optically anisotropic layer can be formed by immobilization by polymerization. It is preferable to fix by polymerization by supplying light irradiation and / or heat, and it is more preferable to fix by polymerization by ultraviolet irradiation.

  The second optically anisotropic layer may be a layer formed by curing any orientation of liquid crystal, and any orientation of homogeneous orientation, homeotropic orientation, hybrid orientation, twist orientation, and tilt orientation. It may be a layer formed by curing the state. Any orientation state can be obtained by selecting a conventionally known material.

An example of the optical film manufactured by the manufacturing method of this invention is shown in FIG.
The optical film of FIG. 1 has a first optical anisotropic layer 12 and a second optical anisotropic layer 14 on a polymer film 10, and the second optical anisotropic layer 14 has the above-mentioned conditions. Therefore, the first optically anisotropic layer 12 is free from white turbidity and has a good optical compensation capability.

When the optical film of FIG. 1 is used for optical compensation of a TN mode, OCB mode, VA mode, and IPS mode liquid crystal display device, the first optical anisotropic layer 12 has the following formulas (VII) to (X): It is preferable to have optical characteristics satisfying the above.
(VII): −10 nm ≦ Re (550) ≦ 10 nm
(VIII): 0 nm ≦ Rth (550) ≦ 200 nm
(IX): −10 nm ≦ Re (630) −Re (450) ≦ 0 nm
(X): −40 nm ≦ Rth (630) −Rth (450) ≦ 0 nm
Furthermore, it is more preferable that the following formulas (VII) ′ to (X) ′ are satisfied.
(VII) ′: −5 ≦ Re (550) ≦ −5 nm
(VIII) ′: 50 nm ≦ Rth (550) ≦ 150 nm
(IX) ′: −5 nm ≦ Re (630) −Re (450) ≦ 0 nm
(X) ′: −30 nm ≦ Rth (630) −Rth (450) ≦ 0 nm
The first optically anisotropic layer satisfying the above formula can be formed by using the above-described preferable polyimide or preferable polyvinyl alcohol, adjusting the coating amount, and setting the thickness within a predetermined range. Further, if desired, after forming the optically anisotropic layer 12 on the polymer film 10 and before forming the second optically anisotropic layer 14, lamination of the polymer film 10 and the optically anisotropic layer 12 is performed. By subjecting the body to a stretching treatment or a shrinking treatment, a layer satisfying the above optical properties is obtained.

When the optical film of FIG. 1 is used for optical compensation of a TN mode, OCB mode, VA mode, and IPS mode liquid crystal display device, the polymer film 10 satisfies the following formulas (I) to (VI): preferable.
(I): 0 nm ≦ Re (550) ≦ 200 nm
(II): 0 nm ≦ Rth (550) ≦ 300 nm
(III): 0 nm ≦ Re (630) −Re (450) ≦ 30 nm
(IV): 0 nm ≦ Rth (630) −Rth (450) ≦ 40 nm
(V): 0 nm ≦ Re (10% RH) −Re (80% RH) ≦ 20 nm
(VI): 0 nm ≦ Rth (10% RH) −Rth (80% RH) ≦ 30 nm
Furthermore, it is more preferable that the following formulas (I) ′ to (VI) ′ are satisfied.
(I) ′: 0 nm ≦ Re (550) ≦ 100 nm
(II) ′: 0 nm ≦ Rth (550) ≦ 250 nm
(III) ′: 5 nm ≦ Re (630) −Re (450) ≦ 30 nm
(IV) ′: 5 nm ≦ Rth (630) −Rth (450) ≦ 40 nm
(V) ′: 0 nm ≦ Re (10% RH) −Re (80% RH) ≦ 15 nm
(VI) ′: 0 nm ≦ Rth (10% RH) −Rth (80% RH) ≦ 20 nm
However, in the above formula, Re (α% RH) is an in-plane retardation value in which the moisture content has reached an equilibrium state at an ambient humidity of 25 ° C. and α% RH, and Rth (α% RHλ) is an ambient humidity of 25 It is the retardation value in the thickness direction at which the water content reached an equilibrium state at a temperature of α °% RH.

  As the polymer film, a cellulose acetate film and a cycloolefin polymer film are preferable. In particular, in order to obtain a polymer film satisfying the above formulas (I) to (VI), it is preferable to prepare a polymer film by a solvent cast method. Moreover, it is preferable to contain the retardation control agent which controls Re or Rth in a polymer film. Examples of preferable cycloolefin polymers used for the production of the cycloolefin polymer film include polymers described in JP-A-2006-188671. In order to produce a cellulose acylate film satisfying the above formulas (I) to (VI), it is preferable to add a compound represented by the following formula (I) as a Re control agent.

In the formula, L ¹ and L ² each independently represent a single bond or a divalent linking group; A ¹ and A ² each independently represent —O— or —NR— (R represents a hydrogen atom or a substituent). ), -S- and -CO-; R ¹ , R ² and R ³ each independently represent a substituent; X represents a nonmetallic atom of Groups 14-16 ( However, a hydrogen atom or a substituent may be bonded to X); n represents any integer from 0 to 2.

  Among the compounds represented by the general formula (I), the Re enhancer is preferably a compound represented by the following general formula (II).

In general formula (II), L ¹ and L ² each independently represents a single bond or a divalent linking group. A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R represents a hydrogen atom or a substituent), —S—, and CO—. R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represents a substituent. n represents an integer of 0 to 2.

In the general formula (I) or (II), the divalent linking group represented by L ¹ and L ² preferably includes the following examples.

  More preferred are -O-, -COO-, and -OCO-.

In general formula (I) or (II), R ¹ is a substituent, and when there are a plurality of R ^{1 s} , they may be the same or different and may form a ring. The following can be applied as examples of the substituent.

  A halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a tert- Butyl group, n-octyl group, 2-ethylhexyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl) Group), a bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms. Bicyclo [1,2,2] heptan-2-yl group, bicyclo [2,2,2] octan-3-yl group), a A kenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group or an allyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, That is, it is a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms is removed, for example, a 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group), a bicycloalkenyl group (substituted or substituted). An unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. Bicyclo [2,2,1] hept-2-en-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group), alkynyl (Preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as an ethynyl group or a propargyl group), an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms such as a phenyl group, p-tolyl group, naphthyl group), a heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound. And more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as a 2-furyl group, a 2-thienyl group, a 2-pyrimidinyl group, and a 2-benzothiazolyl group), a cyano group. Hydroxyl group, nitro group, carboxyl group, alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as methoxy group, ethoxy group, isopropoxy group, Si group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group), aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy group, 2- Methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, for example, trimethylsilyloxy group, tert -Butyldimethylsilyloxy group), heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group) An acyloxy group (preferably a formyloxy group, substituted or unsubstituted having 2 to 30 carbon atoms) Alkylcarbonyloxy group, substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group ), A carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N , N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as methoxycarbonyloxy Base An ethoxycarbonyloxy group, a tert-butoxycarbonyloxy group, an n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, for example, phenoxycarbonyl Oxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group), amino group (preferably amino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, carbon number 6-30 substituted or unsubstituted anilino groups such as amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group), acylamino group (preferably formylamino group, C1-C30 substituted or unsubstituted a Alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group), aminocarbonylamino group (preferably A substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonyl An amino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as a methoxycarbonylamino group, an ethoxycarbonylamino group, a tert-butoxycarbonylamino group, an n-octadecyloxycarboni group; Amino group, N-methyl-methoxycarbonylamino group), aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms such as phenoxycarbonylamino group, p-chlorophenoxy A carbonylamino group, an mn-octyloxyphenoxycarbonylamino group), a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino groups having 1 to 30 carbon atoms, 6 to 6 carbon atoms) 30 substituted or unsubstituted aryl sulfoni An amino group, such as a methylsulfonylamino group, a butylsulfonylamino group, a phenylsulfonylamino group, a 2,3,5-trichlorophenylsulfonylamino group, a p-methylphenylsulfonylamino group, a mercapto group, an alkylthio group (preferably, C1-C30 substituted or unsubstituted alkylthio group, for example, methylthio group, ethylthio group, n-hexadecylthio group), arylthio group (preferably C6-C30 substituted or unsubstituted arylthio group, for example, phenylthio group , P-chlorophenylthio group, m-methoxyphenylthio group), heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio group, 1- Phenyltetrazol-5-ylthio group), sulfamoyl group (preferably Preferably, the substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N -Acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N'-phenylcarbamoyl) sulfamoyl group), sulfo group, alkyl and arylsulfinyl group (preferably substituted or unsubstituted having 1 to 30 carbon atoms) Alkylsulfinyl group, substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably , Substituted or unsubstituted alkyls having 1 to 30 carbon atoms Honyl group, substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, such as methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl group (preferably formyl group, carbon number) A substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms such as an acetyl group and a pivaloylbenzoyl group, and an aryloxycarbonyl group (preferably having a carbon number) 7-30 substituted or unsubstituted aryloxycarbonyl groups such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), alkoxycarbonyl group (preferably , Substituted or non-substituted with 2 to 30 carbon atoms An alkoxycarbonyl group, for example, a methoxycarbonyl group, an ethoxycarbonyl group, a tert-butoxycarbonyl group, an n-octadecyloxycarbonyl group), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, for example, Carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group), aryl and heterocyclic azo group (preferably carbon number) 6-30 substituted or unsubstituted arylazo groups, C3-C30 substituted or unsubstituted heterocyclic azo groups such as phenylazo group, p-chlorophenylazo group, 5-ethylthio-1,3,4-thiadiazole -2-ylazo group), imide group (preferably N-succin) Imide group, N-phthalimido group), phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl group (Preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, for example, phosphinyl group, dioctyloxyphosphinyl group, diethoxyphosphinyl group), phosphinyloxy group (preferably having 2 carbon atoms) -30 substituted or unsubstituted phosphinyloxy group, for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, phosphinylamino group (preferably substituted or substituted with 2 to 30 carbon atoms) Unsubstituted phosphinylamino group such as dimethoxyphosphinylamino group, dimethylaminophosphine Iniruamino group), a silyl group (preferably, represents a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, e.g., trimethylsilyl group, tert- butyldimethylsilyl group, a phenyldimethylsilyl group).

  Among the above substituents, those having a hydrogen atom may be substituted with the above groups after removing this. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

R ¹ is preferably a halogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, cyano group, amino group, more preferably A halogen atom, an alkyl group, a cyano group, and an alkoxy group.

R ² and R ³ each independently represents a substituent. An example of R ¹ is given as an example. Preferred are a substituted or unsubstituted benzene ring and a substituted or unsubstituted cyclohexane ring. More preferred are a benzene ring having a substituent and a cyclohexane ring having a substituent, and more preferred are a benzene ring having a substituent at the 4-position and a cyclohexane ring having a substituent at the 4-position.

R ⁴ and R ⁵ each independently represents a substituent. An example of R ¹ is given as an example. Preferably, it is preferred that substituent constant sigma _p value of Hammett is greater than zero electron withdrawing group, sigma _p value has an electron withdrawing substituent of 0 to 1.5 Further preferred. Examples of such a substituent include a trifluoromethyl group, a cyano group, a carbonyl group, and a nitro group. R ⁴ and R ⁵ may be bonded to form a ring.
As for Hammett's substituent constants σ _p and σ _m , for example, Naoki Inamoto's “Hammett's rule-structure and reactivity-” (Maruzen), edited by the Chemical Society of Japan “New Experimental Chemistry Course 14 Synthesis of Organic Compounds” “Reaction V”, page 2605 (Maruzen), Tadao Nakatani, “Description of theoretical organic chemistry”, page 217 (Tokyo Kagaku Dojin), Chemical Review, 91, 165-195 (1991). .

A ¹ and A ² each independently represent a group selected from the group consisting of —O—, —NR— (R is a hydrogen atom or a substituent), —S—, and CO—. Preferred is —O—, —NR— (R represents a substituent, and examples thereof include R ¹ ) and S—.

X represents a nonmetallic atom belonging to Groups 14-16. However, a hydrogen atom or a substituent may be bonded to X. X is preferably ═O, ═S, ═NR, ═C (R) R (wherein R represents a substituent, and examples of R ¹ are given as examples).
n represents an integer of 0 to 2, preferably 0 or 1.

  Specific examples of the compound represented by the general formula (I) or (II) are shown below, but examples of the Re enhancer are not limited to the following specific examples. Regarding the following compounds, unless otherwise specified, the number in parentheses () indicates the exemplified compound (X).

  The synthesis of the compound represented by the general formula (I) or (II) can be performed with reference to a known method. For example, exemplary compound (1) can be synthesized according to the following scheme.

In the above scheme, the synthesis from compound (1-A) to compound (1-D) is described in “Journal of Chemical Crystallography” (1997); 27 (9); p. 515-526. It can be performed with reference to the method described in 1.
Further, as shown in the above scheme, methanesulfonic acid chloride was added to a tetrahydrofuran solution of the compound (1-E), N, N-diisopropylethylamine was added dropwise and stirred, and then N, N-diisopropylethylamine was added. Exemplary solution (1) can be obtained by adding dropwise a tetrahydrofuran solution of compound (1-D) and then adding a tetrahydrofuran solution of N, N-dimethylaminopyridine (DMAP).

  0.1-20 mass% is preferable with respect to 100 mass parts of cellulose acylates, and, as for the addition amount of the compound of the said formula (I), 0.5-10 mass% is more preferable.

  Further, in order to produce a cellulose acylate film satisfying the above formulas (V) and (VI), cellulose acetate is preferable as the cellulose acylate, and examples thereof include diacetyl cellulose and triacetyl cellulose. In addition, it is preferable to add an additive having a functional group selected from at least a plurality of hydroxyl groups, amino groups, thiol groups, and carboxylic acid groups in one molecule to the cellulose acylate composition. The additive preferably has a plurality of different functional groups in one molecule, and particularly preferably has a hydroxyl group and a carboxylic acid group. Moreover, it is preferable to contain 1-2 aromatic rings as a mother nucleus, and the value obtained by dividing the value obtained by dividing the number of functional groups contained in one molecule by the molecular weight of the additive by 1000 is 10 or more. preferable. These features are that the specific additive binds (hydrogen bond) to the site where cellulose acylate and water molecules interact (hydrogen bonds), and acts to suppress changes in charge distribution due to desorption of water molecules. The details are unclear.

  Examples of the additive having the function include the following compounds, but are not limited thereto.

In the manufacturing process of a cellulose acylate film, it may include a step of heating at a relatively high temperature (about 120 ° C. to about 140 ° C.) for a long time (about several minutes to about 60 minutes), in which case the additive is volatilized. Otherwise, the process will be contaminated. In such a case, it is preferable that the molecular weight can be increased by containing two aromatic rings, and volatility is improved. Moreover, 1 or less hydroxyl machine is contained in one aromatic ring, 3 or less carboxylic acid groups are contained in one aromatic ring, and the sum total of a hydroxyl group and a carboxylic acid group is 2-6. It is preferable to use a single unit because the effect of reducing the fluctuations in Re and Rth with respect to humidity changes is secured.
Moreover, as an aspect of connection of two aromatic rings, structures of the following general formulas (10) to (16) are preferable.

In the formula, R ^{1 to} R ⁶ each represent a hydrogen atom, an alkyl group excluding an aromatic ring, a hydroxyl group, an amino group, a thiol group, or a carboxylic acid group.

  Furthermore, the molecular weight of the additive is preferably 180 to 500. Within the above range, the additive is less likely to be volatilized in the production process, and the compatibility with cellulose acylate is good, which is preferable.

  Examples of specific compounds include, but are not limited to, the following compounds:

  When the polymer film 10 and the first optical anisotropic layer 12 of the optical film of FIG. 1 satisfy the above optical characteristics and are used for optical compensation of a TN mode liquid crystal display device, the second optical anisotropic property The conductive layer 14 is preferably one in which a discotic liquid crystal is hybrid-aligned. When used in an OCB mode liquid crystal display device, the second optically anisotropic layer 14 is preferably a discotic liquid crystal that is hybrid-aligned. When used in a VA mode liquid crystal display device, the second optically anisotropic layer 14 is preferably a positive A plate.

The optical film produced by the method of the present invention can be used as an independent member as it is as an optical compensation film of a liquid crystal display device. Alternatively, it can be attached to a polarizing film and used in a liquid crystal display device as one member of a polarizing plate. Hereinafter, the polarizing plate having the optical film produced by the production method of the present invention will be described.
[Polarizer]
The polarizing plate of the present invention has at least a polarizing film and an optical film manufactured by the manufacturing method of the present invention. The optical film may be directly bonded to the surface of the polarizing film and used as a protective film for the polarizing film. In such an embodiment, an embodiment having a polymer film as a support as shown in FIG. 1 is used, and the back surface of the polymer film (the surface on which the first optical anisotropic layer is not formed) is attached to the polarizing film. It is preferable to bond it to the surface. Moreover, it is preferable that a protective film such as a cellulose acylate film is bonded to the other surface of the polarizing film.

(Polarizing film)
Examples of the polarizing film include an iodine-based polarizing film, a dye-based polarizing film using a dichroic dye, and a polyene-based polarizing film, and any of them may be used in the present invention. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.
(Protective film)
It is preferable to use a transparent polymer film as the protective film to be bonded to the other surface. “Transparent” means that the light transmittance is 80% or more. As the protective film, a cellulose acylate film and a polyolefin film containing polyolefin are preferable. Among the cellulose acylate films, a cellulose triacetate film is preferable. Of the polyolefin films, a polynorbornene film containing a cyclic polyolefin is preferable.
The thickness of the protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

[Liquid Crystal Display]
An optical film manufactured by the manufacturing method of the present invention, and a polarizing plate using the optical film are liquid crystal display devices of various modes, TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensatory Bend), The liquid crystal display device can be used in any display mode such as VA (Vertically Aligned) and ECB (Electrically Controlled Birefringence). In addition, the liquid crystal display device can be any of a transmissive type, a reflective type, and a transflective type.
Among these, the TN mode, VA mode, OCB mode, and IPS mode liquid crystal display devices are more suitable.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Preparation of transparent support>
・ JA-1
A cellulose acylate film (TAC-TD80U manufactured by FUJIFILM Corporation) was prepared. This was used as film JA-1.

-Preparation of JA-2 The composition shown in the following table was put into a mixing tank and stirred while heating to 30 ° C to dissolve each component, thereby preparing a cellulose acylate solution. A cellulose acylate having a total acyl substitution degree of 2.83 was used.

The obtained inner layer dope and outer layer dope were cast on a drum cooled to 0 ° C. using a three-layer co-casting die.
The film having a residual solvent amount of 70% by mass was peeled off from the drum, both ends were fixed with a pin tenter, and the film was dried at 80 ° C. while transporting at a draw ratio of 115% in the transport direction, resulting in a residual solvent amount of 10%. By the way, it was dried at 110 ° C.
Thereafter, it was dried at a temperature of 155 ° C. for 20 minutes to produce a cellulose acetate film (outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) having a residual solvent of 0.3% by mass. This film was used as film JA-2.

-Preparation of JA-3 Each component described in the following table was mixed to prepare a cellulose acylate solution. This cellulose acylate solution was cast on a metal support, the obtained web was peeled from the support, and then stretched under the conditions described in the following table. In the table below, the MD direction means the transport direction. After stretching, it was dried to obtain a cellulose acylate film. This film was used as film JA-3.

-Preparation of JA-4 Each component shown in the following table was mixed to prepare cellulose acylate. This was extruded from a die with a screw rotation speed of 300 rpm, a kneading time of 40 seconds, and an extrusion rate of 200 kg / hr, solidified in 60 ° C. water, and then cut into a diameter of 2 mm and a length of 3 mm. A cylindrical pellet was obtained. Thereafter, using the pellets, melt film formation was performed in the same manner as described in Example 1 of JP-A-2007-2216 to obtain a 140 μm film. This film was stretched under the conditions shown in the table below and used as film JA-4.

-Preparation of JA-5 Each component described in the following table was mixed to prepare a cellulose acylate solution. This cellulose acylate solution was cast on a metal support, the obtained web was peeled from the support, and then stretched under the conditions described in the following table. In the table below, the MD direction means the transport direction. After extending | stretching, it dried and manufactured the cellulose acylate film of the thickness as described in the following table | surface, and used as film JA-5.

-Preparation of JA-6 Each component described in the following table was mixed to prepare a cellulose acylate solution. This cellulose acylate solution was cast on a metal support, the obtained web was peeled from the support, and then stretched under the conditions described in the following table. In the table below, the MD direction means the transport direction. After extending | stretching, it dried and manufactured the cellulose acylate film of the thickness as described in the following table | surface, and used as film JA-6.

-Production of JA-7 A colorless and transparent cast film having a thickness of 100 μm and a residual solvent amount of 0.2% or less was obtained from the resin P2 described in Examples of JP-A-2006-188671 by a methylene chloride cast method. The film was heated to 195 ° C., stretched 1.5 times at a stretching rate of 220% / min, then cooled and taken out to obtain a film. This film was used as film JA-7.

-Preparation of JA-8 Each component described in the following table was mixed to prepare a cellulose acylate solution. This cellulose acylate solution was cast on a metal support, the obtained web was peeled from the support, and then stretched under the conditions described in the following table. In the table below, the MD direction means the transport direction. After stretching, it was dried to obtain a cellulose acylate film. This film was used as film JA-8.

The following tables show the optical characteristics of the films JA-1 to JA-8.

<Saponification treatment>
A 1.0N potassium hydroxide solution (solvent: water / isopropyl alcohol / propylene glycol = 69.2 parts / 15 parts by weight / 15.8 parts by weight) is placed on the transparent supports JA-1 to JA-8 at 10 mL / m. ^{2. After} coating and holding at about 40 ° C. for 30 seconds, the alkaline solution was scraped off, washed with pure water, and water drops were removed with an air knife. Then, it dried at 100 degreeC for 15 second.

<Production of first optically anisotropic layer>
-Preparation of JB-1 Synthesized from 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl A polyimide having a weight average molecular weight (Mw) of 120,000 was dissolved in cyclohexanone to prepare a 15% polyimide solution.
The prepared polyimide solution was applied to the surfaces of JA-1 to JA-5, and the coating film was dried at 100 ° C. for 10 minutes to form polyimide layers JB-1.

-Preparation of JB-2 A polyimide compound (weight average molecular weight (Mw) 120,000) represented by the following structure was dissolved in methyl ethyl ketone to prepare a 15% polyimide solution. The prepared polyimide solution was applied to the surface of JA-6. This coating film was dried at 50 ° C. for 4 minutes to form a polyimide layer JB-2.

-Production of JB-3 PVA124 (manufactured by Kuraray Co., Ltd., polymerization degree: 2400) was dissolved in water to prepare a 7.5% PVA solution. The prepared PVA solution was applied to the surface of JA-4. As a result of drying this coating film at 100 ° C. for 4 minutes, a polyvinyl alcohol (PVA) layer JB-3 having a thickness of 10 μm was formed.

-Preparation of JB-4 Two sheets of cellulose acylate film (TAC-TD80U manufactured by FUJIFILM Corporation) are stacked on JA-4 via a pressure-sensitive adhesive. Formed.

  As described above, laminates C1 to C10 of any of the films JA-1 to 8 and any of JB-1 to 4 formed by the above method were produced. Each optical characteristic is shown in the following table.

<Orientation treatment>
C1 and C2 are each conveyed at a speed of 20 m / min, a rubbing roll (300 mm diameter) is set so as to be rubbed at 90 ° with respect to the longitudinal direction, and rotated at 750 rpm to rub the alignment film installation surface. Treated. C3-9 were rubbed under the same conditions except that the rubbing direction was 45 °.

Example 1
The laminate C1 was 110% longitudinally uniaxially stretched at 160 ° C. to obtain a laminate (C1 ′) with Re = 140 nm and Rth = 250 nm. A coating liquid having the composition shown in the following table was applied to the rubbing surface of this laminate C1 ′, and this was heated at 90 ° C. for 1 minute to orient the liquid crystal monomer, and then a 120 W / cm high-pressure mercury lamp. The monomer was polymerized and immobilized by irradiating with ultraviolet rays for 1 minute. This liquid crystal compound layer (second optically anisotropic layer) was an optically anisotropic layer having a thickness of about 0.8 μm, Re of 100 nm, and nx> ny = nz (positive A plate). . Thus, the optical film 1 was produced.

(Comparative Example 1)
A coating solution having the composition shown in the following table was applied to the rubbing surface of the laminate C1 ′, and this was heat-treated at 90 ° C. for 1 minute. Thereafter, the monomer was polymerized and fixed by ultraviolet irradiation. The obtained laminate became cloudy.

  When JB-1 (film thickness 5.8 μm) was applied on a glass plate and only methyl ethyl ketone was applied, JB-1 became cloudy. On the other hand, when applied in the same manner as toluene used in Example 1, white turbidity did not occur, and changes in optical properties before and after application were ΔRe (before application-after application) = 0.5 nm, ΔRth (before application-after application) = It was 1.0 nm.

(Example 2)
The coating liquid having the composition shown in the following table was applied to the rubbing treated surface of the laminate C2 with a # 2.0 wire bar. Then, it heated for 90 second in a 120 degreeC thermostat, and the discotic liquid crystal compound was orientated. Next, using a 120 W / cm high-pressure mercury lamp at 80 ° C., ultraviolet rays were irradiated for 1 minute to polymerize the discotic liquid crystal compound. Then, it stood to cool to room temperature. The Re retardation value of the obtained optically anisotropic layer measured at a wavelength of 546 nm was 50 nm. The film thickness was 1.3 μm. Thus, an optical film 2 was produced.

(Example 3)
The coating liquid having the composition shown in the table below was applied to the rubbing treated surfaces of the laminates C3 to C9 with a # 2.0 wire bar. Then, it heated for 90 second in a 120 degreeC thermostat, and the discotic liquid crystal compound was orientated. Next, using a 120 W / cm high-pressure mercury lamp at 80 ° C., ultraviolet rays were irradiated for 1 minute to polymerize the discotic liquid crystal compound. Then, it stood to cool to room temperature. The Re retardation value of the obtained optically anisotropic layer measured at a wavelength of 546 nm was 30 nm. The thickness was 0.8 μm. In this way, optical films 3 to 9 were produced.

Example 4
A coating solution containing a rod-like liquid crystal compound having the following composition was prepared.

  The prepared coating solution was continuously applied with a # 5.0 wire bar on the surface of the C10 polyimide layer produced above. The conveyance speed of the film was 20 m / min. The solvent was dried in a step of continuously heating from room temperature to 80 ° C., and then heated in a drying zone at 80 ° C. for 90 seconds to align the rod-like liquid crystal compound. Subsequently, the temperature of the film was maintained at 60 ° C., and the alignment of the liquid crystal compound was fixed by UV irradiation. Subsequently, the film prepared in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. was immersed for 2 minutes, and then immersed in water to sufficiently wash away sodium hydroxide. Then, after being immersed for 1 minute in 5 mmol / L sulfuric acid aqueous solution of 35 degreeC, it was immersed in water and the dilute sulfuric acid aqueous solution was fully washed away. Finally, the sample was thoroughly dried at 120 ° C. Thus, the optical film 10 was produced.

    The Re retardation value of the obtained optically anisotropic layer measured at a wavelength of 546 nm was 0 nm. Rth was -260 nm. It was confirmed that an optically anisotropic layer in which rod-like liquid crystal molecules were aligned substantially perpendicular to the film surface was formed. Thus, the optical film 10 was produced.

(Preparation of polarizing plate)
First, iodine was adsorbed on a stretched polyvinyl alcohol film to prepare a polarizing film.
Then, the back surface (surface in which the 1st optically anisotropic layer is not formed) of the optical films 1-10 produced in Examples 1-4 is made of the polarizing film using a polyvinyl alcohol-based adhesive. Affixed to one side and a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.), which has been saponified using a polyvinyl alcohol adhesive, to the other side of the polarizing film. It was. Thus, 10 types of polarizing plates were produced (polarizing plates 1 to 10).

<Production of VA mode liquid crystal display device>
A pair of polarizing plates (an upper polarizing plate and a lower polarizing plate) provided on a commercially available 37-inch VA mode liquid crystal television (made by Sharp) are peeled off, and the optical film 1 is a liquid crystal cell. One sheet was attached to the observer side and the backlight side through an adhesive so as to be on the side. At this time, each polarizing plate was disposed so that the transmission axis of the polarizing plate on the observer side (upper polarizing plate) and the transmission axis of the polarizing plate on the backlight side (lower polarizing plate) were orthogonal to each other.

<Production of TN mode liquid crystal display device>
A pair of polarizing plates (an upper polarizing plate and a lower polarizing plate) provided in a 20-inch liquid crystal display device (manufactured by Sharp) using a TN type liquid crystal cell are peeled off, and a polarizing plate 2 produced instead is optically The film 2 was attached to the viewer side and the backlight side one by one through an adhesive so that the film 2 would be on the liquid crystal cell side. At this time, each polarizing plate was disposed so that the transmission axis of the polarizing plate on the observer side (upper polarizing plate) and the transmission axis of the polarizing plate on the backlight side (lower polarizing plate) were orthogonal to each other.

<Preparation of OCB mode liquid crystal cell>
A pair of polarizing plates (an upper polarizing plate and a lower polarizing plate) provided on a 23-inch liquid crystal display device (manufactured by Nanao) using an OCB type liquid crystal cell are peeled off, and optically produced polarizing plates 3 to 9 are used instead. The films 3 to 9 were attached to the viewer side and the backlight side one by one through an adhesive so that the films 3 to 9 were on the liquid crystal cell side. At this time, each polarizing plate was disposed so that the transmission axis of the polarizing plate on the observer side (upper polarizing plate) and the transmission axis of the polarizing plate on the backlight side (lower polarizing plate) were orthogonal to each other. The rubbing direction of the alignment film of the liquid crystal cell and the rubbing direction of the optical compensation film were arranged to be antiparallel.

<Production of IPS mode liquid crystal display device>
A liquid crystal cell was taken out from the liquid crystal television TH-32LX500 (manufactured by Matsushita Electric Industrial Co., Ltd.), and the polarizing plate and the optical film which were pasted on the viewer side and the backlight side were peeled off. In this liquid crystal cell, when no voltage was applied and during black display, the liquid crystal molecules were aligned substantially in parallel between the glass substrates, and the slow axis direction was horizontal to the screen.
The produced polarizing plate 10 was bonded to the glass substrate on the backlight side of the parallel alignment cell using an adhesive. A polarizing plate 10 ′ produced by the following method was bonded to the glass substrate on the viewer side. Moreover, it arrange | positioned so that it might orthogonally cross with the absorption axis of the polarizing plate arrange | positioned at the upper and lower sides of a liquid crystal cell.

<Preparation of Polarizing Plate 10 '>
First, iodine was adsorbed on a stretched polyvinyl alcohol film to prepare a polarizing film.
Thereafter, Z-TAC (manufactured by FUJIFILM Corporation) is attached to one surface of the polarizing film using a polyvinyl alcohol adhesive, and the other surface of the polarizing film is coated with a polyvinyl alcohol adhesive. Was used to paste a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.). In this way, a polarizing plate 10 ′ was produced.

<Display performance evaluation>
Next, the liquid crystal display device that has been left in a room at room temperature and humidity (25 ° C., 60% RH) for one week is displayed from black display (L1) to white display (L8) using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). ) And the color tone and contrast ratio (transmittance during white display / transmittance during black display) were evaluated. The same measurement was performed after the liquid crystal display device was left in a room at room temperature and normal humidity (25 ° C., 10% RH) for one week. The evaluation results are shown in Table *.
In Table *, ΔCu′v ′ is the u′v ′ space with respect to the front when displaying black at a polar angle of 60 ° with respect to the normal direction of the screen surface and the azimuth angle direction of 0 to 360 ° of the liquid crystal display screen. The absolute value of a value obtained by subtracting u′v ′ (front) from u′v ′ at a point farthest away in (u′v ′: color coordinate in CIELAB space) is shown.
The contrast is a value calculated from the contrast ratio (transmittance during white display / transmittance during black display).

<Evaluation criteria>
[Evaluation criteria of ΔCu′v ′]
ΔCu′v ′ is less than 0.02 ΔCu′v ′ is 0.02 or more and less than 0.04 ΔΔCu′v ′ is 0.04 or more and less than 0.06 × ΔCu′v ′ is 0. 06 or more

[Evaluation Criteria for Contrast Viewing Angle (Polar Angle Range with Contrast Ratio of 10 or More and No Black Side Inversion)]
◎ Polar angle 80 ° or more in top / bottom / left / right ○ Polar angle 80 ° or more in three directions, top / bottom / left / right △ Polar angle 80 ° or more in two directions, top / bottom / left / right × Polar angle 80 ° in three directions, top / bottom / left / right more than

From the above results, it can be understood that the optical compensation film manufactured by the manufacturing method of the present invention contributed to the improvement of viewing angle characteristics in any of the VA, TN, OCB and IPS mode liquid crystal display devices.
In particular, Re (10% RH) -Re (80% RH) and Rth (10% RH) -Rth (80% RH) of the polymer film used as the support satisfy the formulas (V) and (VI). It was found that the smaller the value, the less the display characteristics are affected by the environmental humidity.

It is a section schematic diagram of an example of an optical film produced using a manufacturing method of the present invention.

Explanation of symbols

10 Polymer film 12 First optical anisotropic layer 14 Second optical anisotropic layer

Claims (15)

A step of preparing a coating solution by dissolving and / or dispersing at least a liquid crystal compound in a solvent, and applying the coating solution to the surface of the first optical anisotropic layer containing a non-liquid crystalline polymer; A method for producing an optical film comprising at least a step of forming a second optically anisotropic layer,
The solvent used for the preparation of the coating solution is selected from the solvents satisfying the following formulas (1) and (2) when only the solvent is applied to the surface of the first optical anisotropic layer ,
(1): ΔRe (550) ≦ 5 nm
(2): ΔRth (550) ≦ 10 nm
However, ΔRe (550) is the difference between the in-plane retardation Re (550) at a wavelength of 550 nm before and after applying the solvent to the first optical anisotropic layer, and ΔRth (550) is the first optical difference. Difference in thickness direction retardation Rth (550) at a wavelength of 550 nm before and after applying the solvent to the isotropic layer :
The method for producing an optical film, wherein the non-liquid crystalline polymer is polyvinyl alcohol or modified polyvinyl alcohol having a polymerization degree of 1000 to 5000 and a saponification degree of 80 to 100%. 2. The method according to claim 1, further comprising a step of performing any one of a stretching process, a shrinking process, and a rubbing process on the first optical anisotropic layer before applying the coating solution. Method. The method according to claim 1 or 2, wherein the solvent is toluene or xylene. It said support method according to any one of claims 1 to 3, characterized in that a film containing cellulose acylate. The method according to any one of claims 1 to 3 , wherein the support is a film containing a cycloolefin polymer. After coating the coating liquid on the surface of the first optically anisotropic layer, the liquid crystal compound molecules in the coating film are aligned, and the alignment state is fixed to form the second optically anisotropic layer. the method according to any one of claims 1 to 5, characterized in that. The second optically anisotropic layer is formed by fixing molecules of the liquid crystal compound to any one of a homogeneous alignment, a homeotropic alignment, a hybrid alignment, a twist alignment, and a tilt alignment. The method of claim 6 . The method according to any one of claims 1 to 7 , wherein the liquid crystal compound is at least one selected from a liquid crystal polymer, a photopolymerizable liquid crystal monomer, and a thermopolymerizable liquid crystal monomer. The optical film which has the 1st and 2nd optically anisotropic layer manufactured by the method of any one of Claims 1-8 . The optical film according to claim 9 , wherein optical characteristics of the first optically anisotropic layer satisfy the following formulas (VII) to (X):
(VII): −10 nm ≦ Re (550) ≦ 10 nm
(VIII): 0 nm ≦ Rth (550) ≦ 200 nm
(IX): −10 nm ≦ Re (630) −Re (450) ≦ 0 nm
(X): −40 nm ≦ Rth (630) −Rth (450) ≦ 0 nm
In the above formulas (VII) to (X), Re (λ) is an in-plane retardation value at a wavelength λnm, and Rth (λ) is a retardation value in the thickness direction at a wavelength λnm. Wherein further comprising a first and a support for supporting the second optical anisotropic layer, the optical properties of the support, according to claim 9 or 10, characterized by satisfying the following formula (I) ~ (VI) Optical film described in:
(I): 0 nm ≦ Re (550) ≦ 200 nm
(II): 0 nm ≦ Rth (550) ≦ 300 nm
(III): 0 nm ≦ Re (630) −Re (450) ≦ 30 nm
(IV): 0 nm ≦ Rth (630) −Rth (450) ≦ 40 nm
(V): 0 nm ≦ Re (10% RH) −Re (80% RH) ≦ 20 nm
(VI): 0 nm ≦ Rth (10% RH) −Rth (80% RH) ≦ 30 nm
However, in the above formulas (I) to (IV), Re (λ) is an in-plane retardation value at a wavelength λnm, and Rth (λ) is a retardation value in the thickness direction at a wavelength λnm, In the above formulas (V) and (VI), Re (α% RH) is an in-plane retardation value in which the moisture content has reached an equilibrium state at an ambient humidity of 25 ° C. and α% RH, and Rth (α% (RHλ) is a retardation value in the thickness direction in which the moisture content has reached an equilibrium state at an ambient humidity of 25 ° C. and α% RH. The optical film according to claim 11, wherein the support contains a compound represented by the following formula (I):

Where L ¹ And L ² Each independently represents a single bond or a divalent linking group; ¹ And A ² Each independently represents a group selected from the group consisting of -O-, -NR- (R represents a hydrogen atom or a substituent), -S-, and -CO-; ¹ , R ² And R ^Three Each independently represents a substituent; X represents a non-metal atom of Groups 14 to 16 (provided that a hydrogen atom or a substituent may be bonded to X); and n represents any of 0 to 2 Represents an integer. A polarizing plate comprising at least a polarizing film and the optical film according to any one of claims 9 to 12 . A liquid crystal display device comprising the polarizing plate according to claim 13 . The liquid crystal display device according to claim 14 , wherein the liquid crystal cell is a TN, OCB, VA, or IPS system.

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