JP2006195295A - Polarization plate and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarization plate, an optical compensating polarization plate and a liquid crystal display (LCD) that use thereof, capable of keeping the quality of display image over a long term. <P>SOLUTION: The polarization plate has at least a hardened membrane, a cellulose acylate film or a transparent base film F, a polarizer, and a transparent base film F, in this order. This polarization plate has the lamination, formed with the hardened film and the cellulose acylate film or with the hardened film, and the transparent base film F to be arranged on either side of the polarizer is low in water vapor permeability, where Re(λ), and Rth(λ) of the transparent base film F is the cellulose acylate film, satisfying the following relations: 0≤Re<SB>(630)</SB>≤10, ¾Rth<SB>(630)</SB>¾≤25, ¾Re<SB>(400)</SB>-Re<SB>(700)</SB>¾≤10, and ¾Rth<SB>(400)</SB>-Rth<SB>(700)</SB>¾≤35. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polarizing plate and a liquid crystal display device.

  Conventionally, cellulose acylate films have been used for photographic supports and various optical materials because of their toughness and flame retardancy. In particular, in recent years, it has been widely used as an optical transparent film for liquid crystal display devices. Cellulose acylate films are excellent as optical materials for devices that handle polarized light such as liquid crystal display devices because of their high optical transparency and high optical isotropy. It has been used as a support for optical protective films that can improve (viewing angle compensation) a protective film and a display viewed from an oblique direction.

In a polarizing plate which is one member for a liquid crystal display device, a protective film is formed by bonding on at least one side of a polarizing film. A general polarizing film is obtained by dyeing a stretched polyvinyl alcohol (PVA) film with iodine or a dichroic dye.
In many cases, as a protective film for a polarizing film, a cellulose acylate film, particularly a triacetyl cellulose film, which can be directly bonded to PVA is used. It is important that the polarizing film protective film is excellent in optical isotropy, and the optical characteristics of the polarizing film protective film greatly influence the characteristics of the polarizing plate.

  In recent liquid crystal display devices, improvement in viewing angle characteristics has been strongly demanded, and optical transparent films such as polarizing film protective films and optical compensation film supports are more optically isotropic. It is required to be sex. In order to be optically isotropic, it is important that the retardation value represented by the product of birefringence and thickness of the optical film is small. In particular, in order to improve display from an oblique direction, it is necessary to reduce not only the retardation (Re) in the front direction but also the retardation (Rth) in the film thickness direction. Specifically, when the optical properties of the optical transparent film are evaluated, the Re measured from the front of the film is small, and it is required that the Re does not change even if the angle is changed.

  Since the liquid crystal display device is always in use for a long time at all times, the polarizing plate is susceptible to physical damage, and if it is damaged, the display image quality is impaired. Reinforcement is desired. Furthermore, long-term durability has been demanded so that the image quality of the liquid crystal display device does not deteriorate even when used for a long time in an environment having temperature and humidity changes. However, when a cellulose acylate film is used as a protective film, there is a problem that the polarizing performance of the polarizing film is deteriorated under a long-term high-temperature and high-humidity environment.

  On the other hand, there has been a cellulose acylate film having a small front Re, but it has been difficult to produce a cellulose acylate film having a small Re change depending on the angle, that is, a small Rth. Therefore, an optical transparent film having a small angle change of Re using a polycarbonate film or a thermoplastic cycloolefin film instead of a cellulose acylate film has been proposed (for example, Patent Documents 1 and 2, ZEONOR ( Zeon Corporation), ARTON (JSR Corporation), etc.). However, when these optically transparent films are used as a protective film for a polarizing film, there is a problem in bonding properties with PVA because the film is hydrophobic. There also remains a problem that the optical characteristics of the entire film surface are non-uniform.

  As a solution to this problem, it is strongly desired to improve the cellulose acylate film which is excellent in the bonding property to PVA by further reducing the optical anisotropy. Specifically, it is an optically isotropic optically transparent film in which Re on the front surface of the cellulose acylate film is substantially zero and the change in retardation angle is small, that is, Rth is also substantially zero.

  In the production of a cellulose acylate film, a compound called a plasticizer is generally added to improve the film forming performance. As types of plasticizers, phosphate triesters such as triphenyl phosphate and biphenyl diphenyl phosphate, phthalates, and the like are disclosed (for example, see Non-Patent Document 1). Among these plasticizers, those having the effect of reducing the optical anisotropy of the cellulose acylate film are known. For example, specific fatty acid esters are disclosed (for example, see Patent Document 3). ). However, the effect of reducing the optical anisotropy of cellulose acylate films using these conventionally known compounds is not sufficient.

Also, recent liquid crystal display devices are required to improve display color. Therefore, an optical transparent film such as a protective film for a polarizing film or a support for an optical compensation film not only reduces Re and Rth in the visible region of a wavelength of 400 to 800 nm, but also changes Re and Rth depending on the wavelength, that is, wavelength dispersion. It needs to be small.
JP 2001-318233 A JP 2002-328233 A JP 2001-247717 A Plastic Materials Course, Volume 17, Nikkan Kogyo Shimbun, “Fiber-Based Resin”, p. 121 (Showa 45)

  An object of the present invention is to provide a polarizing plate capable of maintaining the display image quality of a display such as a liquid crystal display device (hereinafter sometimes referred to as an LCD) at a high quality for a long period of time and an LCD using these.

The present invention is as follows.
(1) A polarizing film comprising at least a cured film, a cellulose acylate film or a transparent substrate film F, a polarizer, and a transparent substrate film F in this order, and the cured film disposed on one side of the polarizer And a laminate comprising a cellulose acylate film or a laminate comprising a cured film and a transparent substrate film F in an atmosphere of 60 ° C. and 95% relative humidity in accordance with JIS-Z-0208. The measured moisture permeability is 1000 g / m ² · day or less.
However, the transparent substrate film F is a cellulose acylate film in which Re ₍ λ ₎ and Rth ₍ λ ₎ satisfy the following formulas (I) and (II).
(I) 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[In the formula, Re ₍ λ ₎ is a front retardation value (unit: nm) at a wavelength λnm, and Rth ₍ λ ₎ is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. ]

  (2) The transparent substrate film F is a cellulose acylate solid containing at least one compound that reduces Re (λ) and Rth (λ) in cellulose acylate having an acyl substitution degree of 2.85 to 3.00. The polarizing plate as described in (1) above, wherein the polarizing plate is obtained by adding 0.01 to 30% by mass relative to the minute.

  (3) When the transparent substrate film F reduces Re (λ) and Rth (λ) and octanol-water partition coefficient (Log P value) is 0-7, The polarizing plate according to (1) or (2), wherein the polarizing plate is obtained by adding 0.01 to 30% by mass with respect to the rate solid content.

  (4) Compounds in which the Re (λ) and Rth (λ) are decreased and the octanol-water partition coefficient (Log P value) is 0 to 7 are represented by the following general formulas (13), (18), (19 The polarizing plate according to (3), wherein the polarizing plate is represented by any of the above.

[In General Formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. However, the total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more. ]

[In General Formula (18), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. ]

[In the general formula (19), R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group or an aryl group. ]

  (5) The transparent substrate film F contains at least one compound that lowers | Re (400) -Re (700) | and | Rth (400) -Rth (700) | The polarizing plate according to any one of (1) to (4), wherein the polarizing plate is contained at a ratio of 0.01 to 30% by mass.

  (6) The polarizing plate according to any one of (1) to (5), wherein the transparent base film F has a thickness of 10 to 120 μm.

  (7) The polarizing plate according to any one of (1) to (6), wherein the cured film has a thickness of 1 to 10 μm.

  (8) The polarizing plate as described in said (7) whose film thickness of the said cured film is 1-5 micrometers.

(9) The cured film contains, as a polymerization unit, at least one compound selected from a compound represented by the following general formula (1) and a compound represented by the following general formula (2): The polarizing plate in any one of (1)-(8).
General formula (1)

(In general formula (1), R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 is an alkylene group or alkylene oxide group having 1 to 5 carbon atoms, and R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. , N represents an integer of 1 or 2)
General formula (2)

（一般式（２）中、Ｒ１、Ｒ３およびｎは上記一般式（１）と同じ意味である）
（１０）前記硬化皮膜上に、防眩層および反射防止層の少なくとも一層を設けたことを特徴とする前記（１）〜（９）のいずれかに記載の偏光板。

(In the general formula (2), R1, R3 and n have the same meaning as in the general formula (1)).
(10) The polarizing plate according to any one of (1) to (9), wherein at least one layer of an antiglare layer and an antireflection layer is provided on the cured film.

(11) The polarizing plate according to any one of (1) to (10), which has an optically anisotropic layer.
(12) An optically anisotropic layer having Re ₍₆₃₀₎ of 0 to 200 nm and | Rth ₍₆₃₀₎ | of 0 to 400 nm is provided on the opposite side of the polarizing plate having the cured film. The polarizing plate as described in (11) above.
(13) A liquid crystal display device comprising the polarizing plate according to any one of (1) to (12).
(14) A liquid crystal display device having a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein the polarizing plate disposed on the viewing side is any one of (1) to (13). The polarizing plate or the optical compensation polarizing plate has a transparent base film F, a polarizer, a cellulose acylate film or a transparent base film F, and a cured film in this order from the liquid crystal cell side. A liquid crystal display device.

  According to the present invention, it is an object of the present invention to provide a polarizing plate capable of maintaining the display image quality of a display such as a liquid crystal display device (hereinafter sometimes referred to as an LCD) at a high quality for a long period of time and an LCD using these.

The polarizing plate of the present invention includes at least a cured film, a cellulose acylate film, or a transparent substrate film F (in this specification, a laminate having a cured film and a cellulose acylate film, and a cured film and a transparent group. The laminate having the material film F may be simply referred to as “functional film”), a polarizer, and a polarizing plate having the transparent base film F in this order, on one side of the polarizer. According to JIS-Z-0208, the laminate comprising the cured film and the cellulose acylate film to be disposed, or the laminate comprising the cured film and the transparent base film F, is at 60 ° C. and 95% relative. The moisture permeability measured in a humidity atmosphere is 1000 g / m ² · day or less.
However, the transparent substrate film F is referred to as a cellulose acylate film (hereinafter referred to as “low retardation cellulose acylate film”) in which Re ₍ λ ₎ and Rth ₍ λ ₎ satisfy the following formulas (I) and (II): There is also.)
(I) 0 ≦ Re ₍₆₃₀₎ ≦ 10 and | Rth ₍₆₃₀₎ | ≦ 25
(II) | Re ₍₄₀₀₎ -Re ₍₇₀₀₎ | ≦ 10 and | Rth ₍₄₀₀₎ −Rth ₍₇₀₀₎ | ≦ 35
[In the formula, Re ₍ λ ₎ is a front retardation value (unit: nm) at a wavelength λnm, and Rth ₍ λ ₎ is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. ]

(Hardened film)
Hereinafter, the cured film used for the polarizing plate of the present invention will be described in detail. In the present specification, the description “(meth) acryloyl” represents the meaning of “at least one of acryloyl and methacryloyl”. The same applies to “(meth) acrylate”, “(meth) acrylic acid” and the like. In addition, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”.

  The cured film preferably has a low moisture permeability, and is preferably a film containing at least one compound selected from the compound group represented by the general formula (1) and the general formula (2) as a polymerization unit. . It is presumed that the alicyclic structure contained in the structure of the polymerized unit has the effect of reducing the moisture permeability.

  In General formula (1) and General formula (2), R1 represents a hydrogen atom or a C1-C3 alkyl group, Preferably, a hydrogen atom, a methyl group, and an ethyl group are represented. R2 represents an alkylene group having 1 to 5 carbon atoms or an alkylene oxide group, and preferably represents a methylene group, an ethylene group, a methylene oxide group, or an ethylene oxide group. R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and preferably represents a hydrogen atom, a methyl group, or an ethyl group. n represents an integer of 1 or 2.

  Although the preferable specific example of a compound represented by General formula (1) is shown, this invention is not limited to these.

  Although the preferable specific example of a compound represented by General formula (2) is shown, this invention is not limited to these.

  The compounds represented by the general formulas (1) and (2) are described in JP-A-60-152515.

In addition to the compounds represented by the general formulas (1) and (2), the polymerizable composition for obtaining a cured film may contain the following polymerizable compound.
For example, as a compound having two or more ethylenically unsaturated groups, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxytri (meta) ) Acrylate, ditrimethylolpropane tetra (meth) acrylate, glycene polypropoxytri (meth) acrylate, di (meth) acrylate of ε-caprolactone adduct of hydroxypenic acid neopenglycol (eg Nippon Kayaku Co., Ltd.) KAYARAD HX-220, HX-620, etc.), pentaerythritol tetra (meth) acrylate, poly (meth) acrylate of dipentaerythritol and ε-caprolactone reaction product, dipentaerythritol Hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, polyglycidyl compounds (polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, glycerin polyglycidyl ether, glycerin polyethoxyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyethoxypolyglycidyl ether, etc.) and (meth) Epoxy (meth) acrylate, which is a reaction product of acrylic acid, and polyfunctional (meth) acrylate containing hydroxyl group And polyisocyanate compounds (tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate) , P-phenylene diisocyanate, etc.) and a polyfunctional urethane acrylate. You may use these individually or in mixture of 2 or more types.

  Furthermore, as vinyl monomers, esters derived from acrylic acid or α-alkylacrylic acid (for example, methacrylic acid), or amides (for example, Ni-propylacrylamide, Nn-butylacrylamide, N- t-butylacrylamide, N, N-dimethylacrylamide, N-methylmethacrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylamidopropyltrimethylammonium chloride, methacrylamide, diacetone acrylamide, acryloylmorpholine, N-methylol Acrylamide, N-methylol methacrylamide, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, n-propyl acrylate, i-propyl acrylate 2-hydroxypropyl acrylate, 2-methyl-2-nitropropyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, t-pentyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-methoxymethoxyethyl acrylate, 2,2,2-trifluoroethyl acrylate, 2,2-dimethylbutyl acrylate, 3-methoxybutyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, n-pentyl acrylate, 3-pentyl acrylate , Octafluoropentyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, cyclopentyl acrylate, cetyl acrylate, benzyl acrylate Benzyl methacrylate, methoxypolyethylene glycol methacrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 4-methyl-2-propylpentyl acrylate, heptadecafluorodecyl acrylate, n-octadecyl acrylate, methyl methacrylate, 2,2,2 -Trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate , 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate Benzyl methacrylate, heptadecafluorodecyl methacrylate, n-octadecyl methacrylate, 2-isobornyl methacrylate, 2-norbornylmethyl methacrylate, 5-norbornen-2-ylmethyl methacrylate, 3-methyl-2-norbol Nylmethyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentanyl methacrylate, pentamethylpiperidyl methacrylate, tetramethylpiperidyl methacrylate, dimethylaminoethyl methacrylate, etc. ), Acrylic acid or α-alkyl acrylic acid (acrylic acid, methacrylic acid, itaconic acid, etc.),

  Vinyl esters (eg, vinyl acetate), esters derived from maleic acid or fumaric acid (dimethyl maleate, dibutyl maleate, diethyl fumarate, etc.), maleimides (N-phenylmaleimide, etc.), maleic acid, fumaric acid , Sodium salt of p-styrenesulfonic acid, acrylonitrile, methacrylonitrile, dienes (eg butadiene, cyclopentadiene, isoprene), aromatic vinyl compounds (eg styrene, p-chlorostyrene, t-butylstyrene, α-methyl) Styrene, sodium styrenesulfonate), N-vinylpyrrolidone, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methyl Cetamide, 1-vinylimidazole, 4-vinylpyridine, vinyl sulfonic acid, sodium vinyl sulfonate, sodium allyl sulfonate, sodium methallyl sulfonate, vinylidene chloride, vinyl alkyl ethers (eg methyl vinyl ether), ethylene, propylene, 1 -Butene, isobutene, etc. are mentioned. Two or more of these vinyl monomers may be used in combination. Vinyl monomers other than these are listed in Research Disclosure No. 1955 (1980, July), JP-A-63-243108, high performance liquid polymer material (Maruzen Co., Ltd., issued on May 20, 1990) Chapter 14 may be used. it can. In the present invention, esters derived from acrylic acid or methacrylic acid, amides, and aromatic vinyl curable resins are particularly preferably used vinyl monomers.

  The compound having two or more ethylenically unsaturated groups and the vinyl monomer described above are manufactured by Nippon Kayaku Co., Ltd. under the trade name of KAYARAD, from Daiichi Kogyo Seiyaku Co., Ltd. under the trade name of New Frontier. It can be obtained under the trade name of Aronix from Co., Ltd. and under the trade name of Funkrill from Hitachi Chemical Co., Ltd.

  The amount of the compound having two or more ethylenically unsaturated groups or the vinyl monomer added to the compound represented by the general formulas (1) and (2) is the required moisture permeability, pencil hardness, refractive index, and transparency. Can be selected arbitrarily depending on the properties, adhesion to the polarizing film, etc., but the total of the compound represented by the general formulas (1) and (2), the compound having two or more ethylenically unsaturated groups, and the vinyl monomer The mass of the compound having two or more ethylenically unsaturated groups and / or the vinyl monomer is preferably 70% by mass or less, more preferably 50% by mass or less, and most preferably 30% by mass or less.

(Initiator)
In order to obtain a cured film, the curable composition contains a polymerization initiator.
(I) When performing heat curing, benzoyl peroxide, dicumyl peroxide, or the like is added.
(Ii) Add benzoyl peroxide / dimethylaniline, cumene hydroperoxide / vanadium accelerator, etc. when performing redox system room temperature curing.
(Iii) In the case of anaerobic curing, hydroperoxide / tertiary amine / sulfimide is added.
(Iv) In the present invention, ultraviolet curing is most preferred and will be described in detail.

  Examples of polymerization initiators that generate radicals by ultraviolet rays include known radical generators such as acetophenones, benzophenones, Michler's ketone, benzoylbenzoate, benzoins, α-acyloxime esters, tetramethylthiuram monosulfide, and thioxanthone. Can be used. In general, sulfonium salts and iodonium salts used as photoacid generators also act as radical generators upon irradiation with ultraviolet rays, and these may be used alone in the present invention. In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone derivatives.

  The addition amount of the polymerization initiator is preferably used in the range of 0.1 to 15% by mass with respect to the total mass of the compound having an ethylenically unsaturated group contained in the curable composition. More preferably, it is used in a mass% range.

  The cured film may be composed of a single layer or a plurality of layers, but is preferably a simple single layer in the production process. The single layer in this case refers to a cured layer formed of the same curable composition, and may be formed by multiple times of application if the composition after application and drying is of the same composition. On the other hand, the term “multiple layers” refers to formation of a plurality of curable compositions having different compositions.

(Fine particles)
In the present invention, fine particles may be added to the curable composition. Since the amount of cure shrinkage of the cured film can be reduced by adding fine particles, adhesion to the substrate is improved, and when the substrate is a plastic film, curling can be reduced, which is preferable. As the fine particles, any of inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used. Examples of the inorganic fine particles include silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, and aluminum oxide particles. Such inorganic fine particles are generally hard and can not only improve shrinkage during curing but also increase the surface hardness. However, since the fine particles generally tend to increase haze, the filling method is adjusted in view of the balance of each necessary characteristic.

  In general, inorganic fine particles have low affinity with the compounds represented by the above general formulas (1) and (2) in the present invention or organic components such as polyfunctional vinyl monomers, so that they form aggregates simply by mixing. Or the cured film after curing may be easily cracked. In the present invention, in order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles can be treated with a surface modifier containing an organic segment. The surface modifier preferably has a functional group capable of forming a bond with or adsorbing to the inorganic fine particles and a functional group having high affinity with the organic component in the same molecule. Examples of the surface modifier having a functional group capable of binding or adsorbing to inorganic fine particles include metal alkoxide surface modifiers such as silane, aluminum, titanium, zirconium, and the like, phosphate groups, sulfate groups, sulfonate groups, carboxylic acid groups, and the like. A surface modifier having an anionic group is preferred. Furthermore, the functional group having a high affinity with the organic component may be simply a combination of the organic component and the hydrophilicity / hydrophobicity, but a functional group that can be chemically bonded to the organic component is preferable, particularly an ethylenically unsaturated group, Or a ring-opening polymerizable group is preferable. A preferred inorganic fine particle surface modifier in the present invention is a curable resin having a metal alkoxide or an anionic group and an ethylenically unsaturated group or a ring-opening polymerizable group in the same molecule.

Representative examples of these surface modifiers include the following unsaturated double bond-containing coupling agents, phosphate group-containing organic curable resins, sulfate group-containing organic curable resins, carboxylic acid group-containing organic curable resins, and the like. It is done.
_{S-1 H 2 C = C} (X) COOC 3 H 6 Si (OCH 3) 3
_{S-2 H 2 C = C} (X) COOC 2 H 4 OTi (OC 2 H 5) 3
_{S-3 H 2 C = C} (X) COOC 2 H 4 OCOC 5 H 10 OPO (OH) 2
S-4 (H ₂ C═C (X) COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH
_{S-5 H 2 C = C} (X) COOC 2 H 4 OSO 3 H
_{S-6 H 2 C = C} (X) COO (C 5 H 10 COO) 2 H
S-7 H ₂ C═C (X) COOC ₅ H ₁₀ COOH
_{S-8 CH 2 CH (O} ) CH 2 OC 3 H 6 Si (OCH 3) 3
(X represents a hydrogen atom or CH ₃ )

  The surface modification of these inorganic fine particles is preferably performed in a solution. When inorganic fine particles are mechanically finely dispersed, a surface modifier is present together, or after finely dispersing inorganic fine particles, the surface modifier is added and stirred, or further before finely dispersing inorganic fine particles The surface may be modified (if necessary, heated, dried and then heated, or pH changed), and then finely dispersed. As the solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specific examples include known solvents such as alcohols, ketones and esters.

  The organic fine particles are not particularly limited, but polymer particles obtained by polymerizing a monomer having an ethylenically unsaturated group, such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyethylene, Polymer particles composed of polypropylene, polystyrene, etc., and polymers of the general formulas (I) and (II) in the present invention are preferably used. Besides, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, polycarbonate, nylon And resin particles such as polyvinyl alcohol, polytetrafluoroethylene, polyethylene terephthalate, polyvinyl chloride, acetylcellulose, nitrocellulose, and gelatin. These particles are preferably crosslinked. As the fine particle disperser, an ultrasonic disperser, a disper, a homogenizer, a dissolver, a polytron, a paint shaker, a sand grinder, a kneader, an Eiger mill, a dyno mill, a coball mill, a high-pressure homogenizer, a fill mix, and the like are preferably used. As the dispersion medium, the above-mentioned solvent for surface modification is preferably used.

  The filling amount of the fine particles is preferably 2 to 40% by volume, more preferably 3 to 25% by volume, and most preferably 5 to 15% by volume with respect to the volume of the cured film after filling.

  In this invention, an inorganic layered compound can also be added in the curable composition used for a cured film. For curing the layered compound, synthetic mica and synthetic smectite are preferably used. Specific examples of synthetic mica include Micromica, MK-100, MK-200, MK-300, Somasif ME-100, MAE, MTE, MEE, MPE, manufactured by Corp Chemical Co., Ltd. , SWN, SAN, STN, SEN, SPN. Synthetic smectites STN and SPN are preferred from the transparency of the cured product and dispersibility in the curable composition.

(solvent)
In this invention, you may use organic solvents, such as a ketone type | system | group, alcohol type | system | group, and ester type, for the coating liquid of a curable composition.

(Curing film preparation method)
In the present invention, the cured coating is prepared by dipping, spinner, spraying, roll coater method, gravure method, wire bar method, slot extrusion coater method (single layer, multi-layer) on the base material. ), By a known thin film forming method such as a slide coater method, and after drying, it can be produced by curing by at least one of ultraviolet irradiation and heating. Drying is preferably performed under conditions where the organic solvent concentration in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The drying conditions are affected by the thermal strength of the substrate, the conveyance speed, the length of the drying process, and the like, but the one having as low an organic solvent content as possible is preferable in terms of increasing the polymerization rate. When an organic solvent is not contained, the drying step can be omitted and ultraviolet irradiation can be performed immediately after coating.

  Furthermore, for the purpose of improving the adhesion between the cellulose acylate film or the transparent base film F and the cured film, if desired, the cellulose acylate film or the transparent base film F may be applied to one or both sides by an oxidation method or a concavo-convex method. Surface treatment can be applied. Examples of the oxidation method include corona discharge treatment, glow discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like. Furthermore, one or more undercoat layers can be provided. Examples of the material for the undercoat layer include copolymers such as vinyl chloride, vinylidene chloride, butadiene, (meth) acrylic acid ester, and vinyl ester, or water-soluble polymers such as latex, low molecular weight polyester, and gelatin. Further, the undercoat layer may contain tin oxide, a metal oxide such as tin oxide / antimony oxide composite oxide, tin oxide / indium oxide composite oxide, or an antistatic agent such as a quaternary ammonium salt.

  The cured film can have a multi-layer structure, and can be produced by appropriately laminating in the order of hardness.

  In the present invention, a curable composition that is cured by irradiation with ultraviolet rays, including an antifouling agent in the produced cured film, or a low surface energy curable resin containing at least one of fluorine and silicon. By laminating an antifouling layer mainly composed of an object, an antifouling cured layer can be obtained.

  The antifouling agent used in the present invention imparts antifouling properties such as water repellency and oil repellency to a cured film, such as when preparing a cured resin composition and applying it on a substrate. As long as there is no inconvenience and the surface of the cured film exhibits water repellency and oil repellency when the cured film is formed, any material may be used. Such a resin includes a cured resin containing at least one of fluorine and silicon.

  Examples of the curable resin include a known fluorine curable resin, a silicon curable resin, or a curable resin having a block containing fluorine and a silicon-containing portion, and a segment having good compatibility with a resin or a metal oxide. A cured resin having a segment containing fluorine or silicon is preferable. By adding to a cured film, fluorine or silicon can be unevenly distributed on the surface.

  Specific examples of these cured resins include block copolymers or graft copolymers of monomers containing fluorine or silicon and other hydrophilic or lipophilic monomers. Examples of the fluorine-containing monomer include perfluoroalkyl group-containing (meth) acrylic esters represented by hexafluoroisopropyl acrylate, heptadecafluorodecyl acrylate, perfluoroalkylsulfonamidoethyl acrylate, perfluoroalkylamidoethyl acrylate, and the like. Examples of the silicon-containing monomer include monomers having a siloxane group by reaction of polydimethylsiloxane and (meth) acrylic acid. Hydrophilic or lipophilic monomers include (meth) acrylic acid esters such as methyl acrylate, hydroxyl-containing polyester and (meth) acrylic acid ester at the terminal, hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylic acid Examples include esters. Examples of commercially available cured resins include acrylic oligomer defensers MCF-300, 312, and 323 having a perfluoroalkyl chain microdomain structure, and perfluoroalkyl group / lipophilic group-containing oligomers such as Megafac F-170 and F- 173, F-175, etc., perfluoroalkyl group / hydrophilic group-containing oligomer Megafac F-171, etc. (Dainippon Ink Chemical Co., Ltd.), segments with excellent surface migration, and segments compatible with resin Fluoroalkyl-based Modiper F-200, 220, 600, 820, etc., which are vinyl monomer block polymers, and Silicon-based Modiper FS-700, 710 (manufactured by Nippon Oil & Fats Co., Ltd.).

  In order to provide an antifouling layer on the cured film, a low surface energy curable resin containing a fluorine atom is preferable, and specifically, JP-A-57-34526 and JP-A-2-19811. And fluorinated hydrocarbon group-containing silicon curable resins and fluorinated hydrocarbon group-containing polymers described in JP-A-3-17901.

  The film thickness of the cured coating is 1 to 10 μm, preferably 1 to 5 μm. When the cured film is provided on the cellulose acylate film or the transparent substrate film F, the moisture permeability decreases as the thickness increases, but the curl increases and the subsequent polarizing plate is produced, for example, the bonding step with the polarizing film. This causes trouble in handling. Further, not only the manufacturing process but also the curling of the polarizing plate is not preferable because it causes display unevenness in the LCD. Therefore, the upper limit of the film thickness of the cured film is preferably in the above range in order to reduce the curl to such an extent that it does not cause curling or is not practically problematic. On the other hand, the lower limit of the film thickness is defined by a range more preferable than physical properties such as moisture permeability and pencil hardness, and is preferably 1 μm or more.

In the polarizing plate of the present invention, a laminate having a cured film and a cellulose acylate film disposed on one side of the polarizer, or a laminate having a cured film and a transparent substrate film F, JIS-Z. −0208 (60 ° C./95% relative humidity) It is essential that the water vapor transmission rate is 1000 g / m ² · day or less. A commercially available cellulose acetate film has a thickness of 80 μm and a moisture permeability of 1400 to 1500 g / m ² · day under the above conditions. When a polarizing plate is produced when the moisture permeability is high, there is a problem in that water vapor enters the polarizing film through the cellulose acylate film or the transparent substrate film F in a high temperature and high humidity environment and the degree of polarization is lowered. As a result of intensive studies, the present inventors have found that a laminate comprising a cured film and a cellulose acylate film disposed on one side of a polarizer, or a laminate comprising a cured film and a transparent substrate film F. When the moisture permeability is 1000 g / m ² · day or less, preferably 800 g / m ² · day or less, more preferably 700 g / m ² · day or less, the performance as a polarizing plate (polarization degree, single plate transmittance) is obtained. They found it useful for practical use without deterioration.

  The pencil hardness of the cured film in the present invention is preferably H or higher, more preferably 2H or higher. The pencil hardness of the polarizing plate can be controlled by adjusting the thickness of the cured film and the composition of the curable composition. In addition, the surface elastic modulus of the cured film in the present invention is preferably 4.0 GPa or more and 10 GPa or less, more preferably 4.5 GPa or more and 9.0 GPa or less in order to obtain sufficient pencil hardness and scratch resistance. Also, it is widely practiced to increase the surface elastic modulus by adding inorganic fine particles, but the brittleness deteriorates as inorganic fine particles are added. When the surface elastic modulus is in the above range, preferable results are obtained in pencil hardness, scratch resistance and brittleness. The surface elastic modulus of the cured film can be controlled by adjusting the composition of the curable composition.

It is preferable that the cure shrinkage rate of the cured film in this invention is 0 to 15%, More preferably, it is 0 to 13%, More preferably, it is 0 to 11%. The curing shrinkage rate is a value obtained by calculating the density of the curable composition before curing and the density of the curable composition after curing, and calculating from the values by the following (Formula A). The density is a value measured (25 ° C.) with MULTIVOLUME PYCNOMETER manufactured by Micrometric.
Formula A: Volume shrinkage = {1- (density before curing / density after curing)} × 100 (%)

  The polarizing plate of the present invention is formed by adhering a functional film having at least a cured film and a cellulose acylate film or a transparent substrate film F on one surface of the polarizer on the surface opposite to the cured film side. can do. A transparent base film F is laminated on the opposite surface of the polarizer.

In the functional film of the present invention, the value when curl is expressed by the following formula B is preferably in the range of minus 15 to plus 15, more preferably in the range of minus 12 to plus 12. Is minus 10 to plus 10. The measurement direction of the curl in the sample at this time is measured in the film conveyance direction in the case of application in a web form.
Formula B: Curl = 1 / R R is the radius of curvature (m)
Curl is an important characteristic for preventing cracks and film peeling during the production, processing, and market handling of a functional film having a cured film. It is preferable that the curl value is in the above range and the curl is small. It is possible to reduce the curl within the above range and to obtain a high surface hardness by setting the volume shrinkage ratio before and after curing of the curable composition for forming a cured film to 15% or less. The curl is measured by using the curl measurement template of Method A in “Measurement Method of Curling of Photographic Film” of JIS K7619-1988. The measurement conditions are 25 ° C., relative humidity 60%, and humidity control time 10 hours. Here, “curl plus” means a curl in which the cured layer coating side of the film is inside the curve, and “minus” means a curl in which the coating side is outside the curve.

  In the functional film of the present invention, when only the relative humidity is changed from 80% to 10% based on the curl measurement method, the absolute value of the difference between the curl values is preferably 24-0, and 15-0. Is more preferable, and 8 to 0 is most preferable. This is a property related to handling, peeling, and cracking when films are attached under various humidity.

  As for the crack resistance of the functional film of the present invention, the radius of curvature at which cracking occurs when rolled with the cured film coating side outward is preferably 30 mm or less, more preferably 25 mm or less, and 20 mm or less. Is most preferred. About the crack of an edge part, it is preferable that there is no crack or the length of a crack is less than 1 mm on average. This crack resistance is an important characteristic for preventing crack defects in handling such as coating, processing, cutting, and sticking of a film having a cured film.

  The haze of the functional film of the present invention is preferably 1.5% or less, more preferably 1.2% or less, and most preferably 1.0% or less.

When the functional film of the present invention is bonded to a polarizing film, a cured film is formed on one side of a cellulose acylate film or a transparent substrate film F, and then alkaline (for example, 1.0 to 3.0 mol / liter hydroxylation). Aqueous sodium solution) is immersed in a bath to saponify the cellulose acylate film or the transparent substrate film F. After neutralization and washing with water, the cellulose acylate film or the transparent base film F surface is bonded to a polarizing film (for example, made of polyvinyl alcohol, iodine, boric acid) with, for example, a polyvinyl alcohol-based adhesive. The saponified cellulose acylate film or transparent base film F adheres firmly to the polarizing film, and is superior to the norbornene resin disclosed in JP-A-10-101907. Moreover, in this invention, the water vapor transmission rate of the laminated body which has the cured film and cellulose acylate film which are arrange | positioned on the single side | surface of a polarizer, or a laminated body which has a cured film and the transparent base film F is 1000 g / Since m ² · day, deterioration of the polarizing film can be suppressed.

(Cellulose acylate film)
The cellulose acylate film used in the present invention is preferably a transparent film-like sheet or plate-like plastic. Specifically, it is a film made of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate because it is optically uniform, has a smooth surface, and has good secondary workability in producing a polarizing plate. Is preferred. The thickness of the cellulose acylate film is preferably 20 to 300 μm, and more preferably 40 to 200 μm. If the film thickness is too thin, the film strength is weak, and if it is thick, the rigidity becomes too large.

(Transparent substrate film F)
The transparent substrate film F in the present invention is a cellulose acylate film (hereinafter referred to as “low retardation cellulose acylate film”) that satisfies the conditions of the above formulas (I) and (II). Hereinafter, the low retardation cellulose acylate film will be described in detail.

[Cellulose acylate raw material cotton]
Examples of the raw material cellulose of the low retardation cellulose acylate film used in the present invention include cotton linter and wood pulp (hardwood pulp, conifer pulp), and any cellulose acylate obtained from any raw material cellulose can be used. May be used as a mixture. Details of these raw material celluloses are, for example, the plastic material course (17) Fibrous resin (manufactured by Marusawa and Uda, Nikkan Kogyo Shimbun, published in 1970) and the Japan Institute of Technology Open Technical Report 2001-1745 (7-8). However, the present invention is not limited to the description.

[Substitution degree of cellulose acylate]
Next, the low retardation cellulose acylate film produced from the above-mentioned cellulose will be described. The low-retardation cellulose acylate film in the present invention is one in which the hydroxyl group of cellulose is acylated, and the substituent is any acetyl group having 2 carbon atoms in the acyl group to those having 22 carbon atoms. Can do. In the present invention, the degree of substitution of the low-retardation cellulose acylate film with the hydroxyl group of cellulose is not particularly limited, but the degree of binding of acetic acid and / or a fatty acid having 3 to 22 carbon atoms substituted for the hydroxyl group of cellulose is measured. The degree of substitution can be obtained by calculation. As a measuring method, it can carry out according to ASTM D-817-91.

  As described above, in the present invention, the degree of substitution of the low-retardation cellulose acylate film with a hydroxyl group of cellulose is not particularly limited, but it is preferable that the degree of acyl substitution with a hydroxyl group of cellulose is 2.50 to 3.00. . Furthermore, the substitution degree is preferably 2.75 to 3.00, and more preferably 2.85 to 3.00.

  Among the acetic acid and / or the fatty acid having 3 to 22 carbon atoms substituted for the hydroxyl group of cellulose, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an aromatic group, and is not particularly limited. It may be a mixture of more than one type. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. These preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, Examples include oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl groups. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are preferable, and acetyl, propionyl and butanoyl are more preferable.

  As a result of intensive studies by the present inventors, among the acyl substituents substituted on the above-mentioned cellulose hydroxyl groups, when the acetyl group / propionyl group / butanoyl group are substantially composed of at least two kinds, the total substitution degree is It was found that the optical anisotropy of the cellulose acylate film can be reduced in the case of 2.50 to 3.00. The degree of acyl substitution is more preferably 2.60 to 3.00, and even more preferably 2.65 to 3.00.

[Degree of polymerization of cellulose acylate]
The degree of polymerization of the low retardation cellulose acylate film used in the present invention is preferably 180 to 700 in terms of viscosity average degree of polymerization. In cellulose acetate, 180 to 550 is more preferable, 180 to 400 is still more preferable, 180 -350 is particularly preferred. If the degree of polymerization is too high, the viscosity of the cellulose acylate dope solution becomes high, and film production becomes difficult due to casting. If the degree of polymerization is too low, the strength of the produced film will decrease. The average degree of polymerization can be measured by Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Society, Vol. This is described in detail in JP-A-9-95538.
Further, the molecular weight distribution of the low retardation cellulose acylate film used in the present invention is evaluated by gel permeation chromatography, and its polydispersity index Mw / Mn (Mw is mass average molecular weight, Mn is number average molecular weight) is small. The molecular weight distribution is preferably narrow. The specific value of Mw / Mn is preferably 1.0 to 3.0, more preferably 1.0 to 2.0, and most preferably 1.0 to 1.6. preferable.

  When the low molecular component is removed, the average molecular weight (degree of polymerization) increases, but the viscosity becomes lower than that of normal cellulose acylate, which is useful. Cellulose acylate having a small amount of low molecular components can be obtained by removing low molecular components from cellulose acylate synthesized by a usual method. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent. In addition, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose. When the amount of the sulfuric acid catalyst is within the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized. When used in the production of cellulose acylate in the present invention, the water content is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly 0.7% by mass or less. . In general, cellulose acylate contains water and is known to have a moisture content of 2.5 to 5% by mass. In order to obtain the moisture content of the cellulose acylate in the present invention, it is necessary to dry, and the method is not particularly limited as long as the desired moisture content is obtained. The methods for synthesizing these cellulose acylates in the present invention are described in detail on pages 7 to 12 in the Japan Society for Invention and Innovation (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society for Invention). .

  The low retardation cellulose acylate film used in the present invention may be used by mixing two or more different types of cellulose acylates within the aforementioned ranges such as substituent, substitution degree, polymerization degree, molecular weight distribution. it can.

[Additive to cellulose acylate]
The low retardation cellulose acylate film used in the present invention has various additives (for example, a compound that reduces optical anisotropy, a wavelength dispersion adjusting agent, fine particles, a plasticizer, an ultraviolet ray inhibitor, an anti-degradation agent, Release agents, optical property modifiers, etc.) can be added and these are described below. Moreover, the addition time may be any in the dope preparation process (the preparation process of the cellulose acylate solution), but a step of adding and preparing an additive may be performed at the end of the dope preparation process.
By adjusting the amount of these additives added, which is a requirement of the present invention,
(I) 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
Can be met.
Preferably,
(I) 0 ≦ Re (630) ≦ 5 and | Rth (630) | ≦ 20,
(II) | Re (400) −Re (700) | ≦ 6 and | Rth (400) −Rth (700) | ≦ 20.
In the formula, Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm.

Contains at least one compound that reduces the optical anisotropy of the low retardation cellulose acylate film used in the present invention, particularly the retardation Rth in the film thickness direction, within the range satisfying the following formulas (III) and (IV). I want to see that.
(III) (Rth (A) −Rth (0)) / A ≦ −1.0
(IV) 0.01 ≦ A ≦ 30
[Wherein Rth (A) is Rth (nm) of a film containing A% of a compound that lowers Rth, Rth (0) is Rth (nm) of a film not containing a compound that lowers Rth, and A is cellulose acylate. This is the mass (%) of the compound when the solid mass of the rate is 100. ]
The above formulas (III) and (IV) are as follows: (III) (Rth (A) −Rth (0)) / A ≦ −2.0
(IV) 0.05 ≦ A ≦ 25
It is more desirable to be
(III) (Rth (A) −Rth (0)) / A ≦ −3.0
(IV) 0.1 ≦ A ≦ 20
It is even more desirable.

[Structural characteristics of compounds that reduce the optical anisotropy of low retardation cellulose acylate films]
Hereinafter, the compound that reduces the optical anisotropy of the low retardation cellulose acylate film will be described. As a result of intensive studies, the present inventors have sufficiently reduced the optical anisotropy by using a compound that suppresses in-plane and film thickness orientation of cellulose acylate in the film, and Re and Rth are It was close to zero. For this purpose, it is advantageous that the compound that lowers the optical anisotropy is sufficiently compatible with cellulose acylate, and the compound itself does not have a rod-like structure or a planar structure. Specifically, when a plurality of planar functional groups such as aromatic groups are provided, a structure having these functional groups in a non-planar rather than the same plane is advantageous.

(Log P value)
In producing a low retardation cellulose acylate film in the present invention, as described above, the compound that suppresses the orientation of the cellulose acylate in the film in the plane and in the film thickness direction and reduces the optical anisotropy. Of these, compounds having an octanol-water partition coefficient (log P value) of 0 to 7 are preferred. A compound having a log P value of more than 7 is poor in compatibility with cellulose acylate, and tends to cause film turbidity or powder blowing. In addition, since a compound having a log P value smaller than 0 has high hydrophilicity, the water resistance of the cellulose acylate film may be deteriorated. A more preferable range of the logP value is 1 to 6, and a particularly preferable range is 1.5 to 5.
The octanol-water partition coefficient (log P value) can be measured by a flask immersion method described in JIS Japanese Industrial Standard Z7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement. As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987).), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163 (1989).) , Broto's fragmentation method (Eur. J. Med. Chem.-Chim. Theor., 19, 71 (1984).) And the like are preferably used, but Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27 , 21 (1987). When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the desired range by the Crippen's fragmentation method. In addition, the value of logP described in this specification is determined by the Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)).

[Physical properties of compounds that reduce optical anisotropy]
The compound that decreases the optical anisotropy may or may not contain an aromatic group. The compound that reduces the optical anisotropy preferably has a molecular weight of 150 or more and 3000 or less, more preferably 170 or more and 2000 or less, and particularly preferably 200 or more and 1000 or less. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.
The compound that reduces optical anisotropy is preferably a liquid at 25 ° C. or a solid having a melting point of 25 to 250 ° C., more preferably a liquid at 25 ° C. or a melting point of 25 to 200. C solid. Moreover, it is preferable that the compound which reduces optical anisotropy does not volatilize in the process of dope casting and drying of cellulose acylate film production.
The amount of the compound that decreases the optical anisotropy is preferably 0.01 to 30% by mass, more preferably 1 to 25% by mass, more preferably 5 to 20%, based on the solid content of cellulose acylate. It is particularly preferable that the content is% by mass.
The compound that decreases the optical anisotropy may be used alone, or two or more compounds may be mixed and used in an arbitrary ratio.
The timing for adding the compound for reducing the optical anisotropy may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  The compound that reduces the optical anisotropy is such that the average content of the compound in the portion from the surface on at least one side to 10% of the total film thickness is the compound in the central portion of the low retardation cellulose acylate film. 80-99% of the average content. The amount of the compound present can be determined, for example, by measuring the amount of the compound at the surface and in the center by a method using an infrared absorption spectrum described in JP-A-8-57879.

  Specific examples of the compound for reducing the optical anisotropy of the low retardation cellulose acylate film used in the present invention are represented by any one of the general formulas (13), (18) and (19). However, the present invention is not limited to these compounds.

The compound of the general formula (13) will be described.
In the general formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Further, the total number of carbon atoms of R ¹ , R ² and R ³ is particularly preferably 10 or more. R ¹ , R ² and R ³ may be substituted, and the substituent is preferably a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group and a sulfonamide group, and an alkyl group, an aryl group, an alkoxy group, A sulfone group and a sulfonamide group are particularly preferred. Further, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and more preferably 6 to 20 (E.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t-octyl, undecyl, Dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred. As the aryl group, those having 6 to 30 carbon atoms are preferable, and those having 6 to 24 carbon atoms (for example, phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, triphenylphenyl) are particularly preferable. Preferred examples of the compound represented by the general formula (13) are shown below, but the present invention is not limited to these specific examples.

  Although the preferable example of a compound represented by General formula (18) or General formula (19) below is shown below, this invention is not limited to these specific examples. In the compound represented by the general formula (18) or the general formula (19), specific examples of the alkyl group and the aryl group are the same as those in the general formula (13).

In the formula, Pr ⁱ represents an isopropyl group.

[Wavelength dispersion adjusting agent]
A compound that lowers the wavelength dispersion of the low retardation cellulose acylate film (hereinafter also referred to as a wavelength dispersion adjusting agent) will be described. In order to improve the Rth wavelength dispersion of the low retardation cellulose acylate film used in the present invention, the Rth wavelength dispersion represented by the following formula (iv) ΔRth = | Rth (400) −Rth (700) It is preferable to contain at least one compound that reduces | in the range satisfying the following formulas (v) and (vi).
(Iv) ΔRth = | Rth (400) −Rth (700) |
(V) (ΔRth (B) −ΔRth (0)) / B ≦ −2.0
(Vi) 0.01 ≦ B ≦ 30
[Wherein, ΔRth (B) is ΔRth (nm) of a film containing B% of a compound that lowers Rth wavelength dispersion, and ΔRth (0) is ΔRth (nm of a film not containing a compound that reduces Rth wavelength dispersion) ) And B are the mass (%) of the compound when the mass of the solid content of cellulose acylate is 100. ]
The above formulas (v) and (vi) are: (v) (ΔRth (B) −ΔRth (0)) / B ≦ −3.0
(Vi) 0.05 ≦ B ≦ 25
It is more desirable to be
(V) (ΔRth (B) −ΔRth (0)) / B ≦ −4.0
(Vi) 0.1 ≦ B ≦ 20
It is even more desirable.
The above-mentioned wavelength dispersion adjusting agent has an absorption in the ultraviolet region of 200 to 400 nm, and lowers both | Re (400) -Re (700) | and | Rth (400) -Rth (700) | The compound to be made is preferable, and it is good to use 0.01-30 mass% with respect to cellulose acylate solid content.

  The Re and Rth values of the low retardation cellulose acylate film generally have a wavelength dispersion characteristic that is larger on the long wavelength side than on the short wavelength side. Therefore, it is required to smooth the chromatic dispersion by increasing Re and Rth on the relatively short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance on the long wavelength side is larger than that on the short wavelength side. If the compound itself is isotropically present inside the cellulose acylate film, it is assumed that the birefringence of the compound itself, and thus the wavelength dispersion of Re and Rth, is large on the short wavelength side as well as the wavelength dispersion of absorbance. .

  Therefore, the Re retardation of the low retardation cellulose acylate film can be obtained by using the compound having absorption in the ultraviolet region of 200 to 400 nm as described above and having the wavelength dispersion of Re and Rth of the compound itself large on the short wavelength side. , Rth wavelength dispersion can be prepared. For this purpose, the compound for adjusting the wavelength dispersion is required to be sufficiently uniformly compatible with the low retardation cellulose acylate film. The absorption band range in the ultraviolet region of such a compound is preferably 200 to 400 nm, more preferably 220 to 395 nm, and even more preferably 240 to 390 nm.

  In recent years, liquid crystal display devices such as televisions, notebook personal computers, and mobile portable terminals have been required to have excellent transmittance of optical members used in liquid crystal display devices in order to increase luminance with less power. In that respect, a compound having absorption in the ultraviolet region of 200 to 400 nm and lowering | Re (400) -Re (700) | and | Rth (400) -Rth (700) | When added to an acylate film, the spectral transmittance is required to be excellent. In the low retardation cellulose acylate film used in the present invention, it is preferable that the spectral transmittance at a wavelength of 380 nm is 45% or more and 95% or less and the spectral transmittance at a wavelength of 350 nm is 10% or less.

  As described above, the wavelength dispersion adjusting agent preferably used in the present invention preferably has a molecular weight of 250 to 1000 from the viewpoint of volatility. More preferably, it is 260-800, More preferably, it is 270-800, Most preferably, it is 300-800. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.

  It is preferable that the wavelength dispersion adjusting agent does not volatilize during the dope casting and drying process for producing the cellulose acylate film.

(Compound addition amount)
The added amount of the wavelength dispersion adjusting agent preferably used in the present invention is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass with respect to the solid content of cellulose acylate. 0.2 to 10% by mass is particularly preferable.

(Method of compound addition)
These wavelength dispersion adjusting agents may be used alone or in combination of two or more compounds at an arbitrary ratio.
The timing of adding these wavelength dispersion adjusting agents may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  Specific examples of the wavelength dispersion adjusting agent preferably used in the present invention include, for example, benzotriazole compounds, benzophenone compounds, cyano group-containing compounds, oxybenzophenone compounds, salicylic acid ester compounds, nickel complex compounds, and the like. However, the present invention is not limited to these compounds. Hereinafter, preferred compounds are exemplified.

  As the benzotriazole-based compound, those represented by the general formula (101) are preferably used as a wavelength dispersion adjusting agent in the present invention.

Formula (101) Q ¹ -Q ² -OH

(In the formula, Q ¹ represents a nitrogen-containing aromatic heterocycle, and Q ² represents an aromatic ring.)

Q ¹ represents a nitrogen-containing aromatic heterocycle, preferably a 5- to 7-membered nitrogen-containing aromatic heterocycle, more preferably a 5- to 6-membered nitrogen-containing aromatic heterocycle, such as imidazole, Pyrazole, triazole, tetrazole, thiazole, oxazole, selenazole, benzotriazole, benzothiazole, benzoxazole, benzoselenazole, thiadiazole, oxadiazole, naphthothiazole, naphthoxazole, azabenzimidazole, purine, pyridine, pyrazine, pyrimidine, pyridazine , Triazine, triazaindene, tetrazaindene and the like, more preferably a 5-membered nitrogen-containing aromatic heterocycle, specifically, imidazole, pyrazole, triazole, tetrazole, thiazole, oxa Lumpur, benzotriazole, benzothiazole, benzoxazole, thiadiazole, oxadiazole preferably, particularly preferably benzotriazole.
The nitrogen-containing aromatic heterocycle represented by Q ¹ may further have a substituent, and the substituent T described below can be applied as the substituent. In addition, when there are a plurality of substituents, each may be condensed to form a ring.

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring is preferably (preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, benzene ring, naphthalene ring etc.), more preferably 6 carbon atoms. An aromatic hydrocarbon ring having 20 to 20 carbon atoms, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms.), More preferably a benzene ring.
The aromatic heterocycle is preferably an aromatic heterocycle containing a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring include, for example, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, Examples include phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. Preferred examples of the aromatic heterocycle include pyridine, triazine, and quinoline.
The aromatic ring represented by Q ² is preferably an aromatic hydrocarbon ring, more preferably a naphthalene ring or a benzene ring, and particularly preferably a benzene ring. Q ² may further have a substituent, and the substituent T described later is preferable.
Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having a carbon number) 1 to 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more Preferably it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl). An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms. Nzoyloxy and the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. And sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl and methylsulfamoyl). , Dimethylsulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl). , Methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio etc.), arylthio group (preferably Has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably Has 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms) More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, diethyl phosphoric acid amide, phenylphosphoric acid amide etc. are mentioned. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl , Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms). For example, trimethylsilyl, triphenylsilyl, etc.) . These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

As the general formula (101), a compound represented by the following general formula (101-A) is preferable.
General formula (101-A)

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represents a hydrogen atom or a substituent)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom or a substituent, and the substituent T described above can be applied as the substituent. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.
R ¹ and R ³ are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups, alkoxy groups, aryloxy groups, hydroxy groups, and halogen atoms, more preferably hydrogen atoms. An atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably an alkyl group having 1 to 12 carbon atoms (preferably 4 to 12 carbon atoms).

R ² and R ⁴ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, and a halogen atom, more preferably A hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom and a methyl group, most preferably Is a hydrogen atom.

R ⁵ and R ⁸ are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups, alkoxy groups, aryloxy groups, hydroxy groups, and halogen atoms, more preferably hydrogen atoms. An atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom and a methyl group, most preferably It is a hydrogen atom.

R ⁶ and R ⁷ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, and a halogen atom, more preferably a hydrogen atom. An atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, more preferably a hydrogen atom and a halogen atom, and particularly preferably a hydrogen atom and a chlorine atom.

More preferable as the general formula (101) is a compound represented by the following general formula (101-B).
General formula (101-B)

(In formula, R < ¹ >, R < ³ >, R < ⁶ > and R < ⁷ > are synonymous with those in general formula (101-A), and their preferred ranges are also the same.)

  Specific examples of the compound represented by formula (101) are listed below, but the present invention is not limited to the following specific examples.

  Among the benzotriazole compounds listed in the above examples, when a low retardation cellulose acylate film used in the present invention is produced without including those having a molecular weight of 320 or less, it is confirmed that it is advantageous in terms of retention. It was done.

In addition, as the benzophenone compound which is one of the wavelength dispersion adjusting agents used in the present invention, those represented by the general formula (102) are preferably used.
Formula (102)

(In the formula, Q ¹ and Q ² each independently represent an aromatic ring. X represents NR (R represents a hydrogen atom or a substituent), an oxygen atom or a sulfur atom.)

The aromatic ring represented by Q ¹ and Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring represented by Q ¹ and Q ² is preferably (preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring, a naphthalene ring, etc.). More preferably an aromatic hydrocarbon ring having 6 to 20 carbon atoms, still more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms.) More preferably, it is a benzene ring.
The aromatic heterocycle represented by Q ¹ and Q ² is preferably an aromatic heterocycle containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, Examples include quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, and tetrazaindene. Preferred examples of the aromatic heterocycle include pyridine, triazine, and quinoline.
The aromatic ring represented by Q ¹ and Q ² is preferably an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms, still more preferably a substituted or unsubstituted benzene ring. is there.
Q ¹ and Q ² may further have a substituent, and the substituent T described later is preferable, but the substituent does not contain a carboxylic acid, a sulfonic acid, or a quaternary ammonium salt. Further, if possible, substituents may be linked to form a ring structure.

  X represents NR (R represents a hydrogen atom or a substituent. Substituent T described later can be applied as the substituent), an oxygen atom or a sulfur atom, and X is preferably NR (R is preferably an acyl group) A sulfonyl group, and these substituents may be further substituted.) Or an oxygen atom, particularly preferably an oxygen atom.

  Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having a carbon number) 1 to 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more Preferably it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl). An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms. Nzoyloxy and the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. And sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as sulfamoyl and methylsulfamoyl). , Dimethylsulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl). , Methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio etc.), arylthio group (preferably Has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably Has 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms) More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, diethyl phosphoric acid amide, phenylphosphoric acid amide etc. are mentioned. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl , Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms). For example, trimethylsilyl, triphenylsilyl, etc.) . These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

As the general formula (102), a compound represented by the following general formula (102-A) is preferable.
Formula (102-A)

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ each independently represents a hydrogen atom or a substituent.)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , and R ⁹ each independently represent a hydrogen atom or a substituent, and the above-mentioned substituent T is applied as the substituent. it can. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ and R ⁹ are preferably a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryl An oxy group, a hydroxy group and a halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom, still more preferably a hydrogen atom and a carbon 1-12 alkyl group. Particularly preferred are a hydrogen atom and a methyl group, and most preferred is a hydrogen atom.

R ² is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom or one carbon atom. An alkyl group having -20 carbon atoms, an amino group having 0-20 carbon atoms, an alkoxy group having 1-12 carbon atoms, an aryloxy group having 6-12 carbon atoms, and a hydroxy group, and more preferably an alkoxy group having 1-20 carbon atoms. And particularly preferably an alkoxy group having 1 to 12 carbon atoms.

R ⁷ is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, a halogen atom, more preferably a hydrogen atom or one carbon atom. An alkyl group having -20 carbon atoms, an amino group having 0-20 carbon atoms, an alkoxy group having 1-12 carbon atoms, an aryloxy group having 6-12 carbon atoms, and a hydroxy group, more preferably a hydrogen atom, having 1-20 carbon atoms. An alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably a methyl group), particularly preferably a methyl group or a hydrogen atom.

More preferable as the general formula (102) is a compound represented by the following general formula (102-B).
General formula (102-B)

(Wherein R ¹⁰ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group.)

R ¹⁰ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted aryl group. Applicable.
R ¹⁰ is preferably a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group having 5 to 20 carbon atoms, and still more preferably a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms. (Including n-hexyl group, 2-ethylhexyl group, n-octyl group, n-decyl group, n-dodecyl group, benzyl group, etc.), particularly preferably a substitution of 6 to 12 carbon atoms or It is an unsubstituted alkyl group (2-ethylhexyl group, n-octyl group, n-decyl group, n-dodecyl group, benzyl group).

The compound represented by the general formula (102) can be synthesized by a known method described in JP-A-11-12219.
Specific examples of the compound represented by the general formula (102) are given below, but the present invention is not limited to the following specific examples.

As the compound containing a cyano group, which is one of the wavelength dispersion adjusting agents used in the present invention, those represented by the general formula (103) are preferably used.
General formula (103)

(In the formula, Q ¹ and Q ² each independently represents an aromatic ring. X ¹ and X ² represent a hydrogen atom or a substituent, and at least one of them represents a cyano group.)
The aromatic ring represented by Q ¹ and Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.

  The aromatic hydrocarbon ring is preferably (preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, benzene ring, naphthalene ring etc.), more preferably 6 carbon atoms. An aromatic hydrocarbon ring having 20 to 20 carbon atoms, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms.), More preferably a benzene ring.

  The aromatic heterocycle is preferably an aromatic heterocycle containing a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring include, for example, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, Examples include phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. Preferred examples of the aromatic heterocycle include pyridine, triazine, and quinoline.

The aromatic ring represented by Q ¹ and Q ² is preferably an aromatic hydrocarbon ring, and more preferably a benzene ring.
Q ¹ and Q ² may further have a substituent, and a substituent T described later is preferable. Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having a carbon number) 1 to 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more Preferably it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl). An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms. Nzoyloxy and the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. And sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl and methylsulfamoyl). , Dimethylsulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl). , Methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio etc.), arylthio group (preferably Has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably Has 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms) More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, diethyl phosphoric acid amide, phenylphosphoric acid amide etc. are mentioned. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl , Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms). For example, trimethylsilyl, triphenylsilyl, etc.) . These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

X ¹ and X ² each represent a hydrogen atom or a substituent, and at least one of them represents a cyano group. The substituent T described above can be applied to the substituents represented by X ¹ and X ² . The substituents represented by X ¹ and X ² may be further substituted with other substituents, and X ¹ and X ² may be condensed to form a ring structure.

X ¹ and X ² are preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, or an aromatic heterocycle, and more preferably a cyano group, a carbonyl group, a sulfonyl group, An aromatic heterocycle, more preferably a cyano group or a carbonyl group, and particularly preferably a cyano group or an alkoxycarbonyl group (—C (═O) OR (R is an alkyl group having 1 to 20 carbon atoms, 6 carbon atoms). ˜12 aryl groups and combinations thereof.

Preferred as the general formula (103) is a compound represented by the following general formula (103-A).
General formula (103-A)

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. X ¹ and X ² Are the same as those in formula (103), and the preferred range is also the same.)

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and examples of the substituent include the substituents described above. T is applicable. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.

R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ , and R ¹⁰ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, An alkoxy group, an aryloxy group, a hydroxy group, and a halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom, still more preferably a hydrogen atom and carbon 1-12. An alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

R ³ and R ⁸ are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups, alkoxy groups, aryloxy groups, hydroxy groups, halogen atoms, more preferably hydrogen atoms. , An alkyl group having 1 to 20 carbon atoms, an amino group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group, more preferably a hydrogen atom and a carbon number. An alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms, particularly preferably a hydrogen atom.

More preferable as the general formula (103) is a compound represented by the following general formula (103-B).
General formula (103-B)

(Wherein R ³ and R ⁸ have the same meanings as those in formula (103-A), and preferred ranges are also the same. X ³ represents a hydrogen atom or a substituent.)

X ³ represents a hydrogen atom or a substituent. As the substituent, the above-described substituent T can be applied, and if possible, the substituent may be further substituted with another substituent. X ³ is preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group or an aromatic heterocyclic ring, more preferably a cyano group, a carbonyl group, a sulfonyl group or an aromatic heterocyclic ring. More preferably a cyano group or a carbonyl group, and particularly preferably a cyano group or an alkoxycarbonyl group (—C (═O) OR (R is an alkyl group having 1 to 20 carbon atoms, an aryl having 6 to 12 carbon atoms). Group and a combination thereof).

As the general formula (103), a compound represented by the general formula (103-C) is more preferable.
General formula (103-C)

(Wherein R ³ and R ⁸ have the same meanings as those in formula (103-A), and the preferred ranges are also the same. R ²¹ represents an alkyl group having 1 to 20 carbon atoms.)

R ²¹ is preferably an alkyl group having 2 to 12 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms, and still more preferably 6 carbon atoms when both R ³ and R ⁸ are hydrogen. To 12 alkyl groups, particularly preferably n-octyl group, tert-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, most preferably 2-ethylhexyl group. It is.

When R ³ and R ⁸ are preferably other than hydrogen as R ²¹ , the compound represented by the general formula (103-C) has a molecular weight of 300 or more and an alkyl group having 20 or less carbon atoms. preferable.

  The compound represented by the general formula (103) can be synthesized by the method described in Journal of American Chemical Society 63, 3452 (1941).

  Specific examples of the compound represented by the general formula (103) are given below, but the present invention is not limited to the following specific examples.

[Matting agent fine particles]
It is preferable to add fine particles as a matting agent to the low retardation cellulose acylate film used in the present invention. The fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silica Mention may be made of magnesium and calcium phosphates. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more. Those having an average primary particle size as small as 5 to 16 nm are more preferred because they can reduce the haze of the film. The apparent specific gravity is preferably 90 to 200 g / liter or more, and more preferably 100 to 200 g / liter or more. A larger apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.

  These fine particles usually form secondary particles having an average particle diameter of 0.1 to 3.0 μm, and these fine particles are present as aggregates of primary particles in the film, and 0.1 to 0.1 μm on the film surface. An unevenness of 3.0 μm is formed. The secondary average particle size is preferably from 0.2 μm to 1.5 μm, more preferably from 0.4 μm to 1.2 μm, and most preferably from 0.6 μm to 1.1 μm. The primary and secondary particle sizes were determined by observing the particles in the film with a scanning electron microscope and determining the diameter of a circle circumscribing the particles as the particle size. In addition, 200 particles were observed at different locations, and the average value was taken as the average particle size.

  As fine particles of silicon dioxide, for example, commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.) can be used. Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Among these, Aerosil 200V and Aerosil R972V are fine particles of silicon dioxide having a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more, and while maintaining the turbidity of the optical film low, friction This is particularly preferable because the effect of reducing the coefficient is great.

In order to obtain a low retardation cellulose acylate film having particles having a small secondary average particle diameter in the present invention, several methods are conceivable when preparing a dispersion of fine particles. For example, a fine particle dispersion prepared by stirring and mixing a solvent and fine particles is prepared in advance, and the fine particle dispersion is added to a separately prepared small amount of cellulose acylate solution and dissolved by stirring. Further, a main cellulose acylate solution (dope solution) and There is a way to mix. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are more difficult to reaggregate. In addition, after adding a small amount of cellulose ester to the solvent and dissolving with stirring, add fine particles to this and disperse with a disperser to make this fine particle additive solution, which is sufficiently mixed with the dope solution using an in-line mixer. There is also a method of mixing. The present invention is not limited to these methods, but the concentration of silicon dioxide when the silicon dioxide fine particles are mixed and dispersed with a solvent or the like is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and 15 to 20%. Mass% is most preferred. A higher dispersion concentration is preferable because the liquid turbidity with respect to the added amount is lowered, and haze and aggregates are improved. The addition amount of the matting agent fine particles in the final cellulose acylate dope solution is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, more preferably 0.08 to 0.16 g per m ^3. Is most preferred.

  The solvent used is preferably lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. Although it does not specifically limit as solvents other than a lower alcohol, It is preferable to use the solvent used at the time of film forming of a cellulose ester.

[Plasticizer, degradation inhibitor, release agent]
In addition to the compound that optically decreases anisotropy and the wavelength dispersion adjusting agent, the low retardation cellulose acylate film used in the present invention includes various additives (for example, for example, as described above) Plasticizers, UV inhibitors, degradation inhibitors, release agents, infrared absorbers, etc.), which may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, mixing of ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, and similarly, mixing of a plasticizer is described in, for example, JP-A-2001-151901. Furthermore, as an infrared absorber, it describes in Unexamined-Japanese-Patent No. 2001-194522, for example. Further, the addition time may be any time in the dope production process, but it is preferable to add an additive at the end of the dope production process. Furthermore, the amount of each additive added is not particularly limited as long as the function is exhibited. Moreover, when the low retardation cellulose acylate film is formed from multiple layers, the types and amounts of additives in each layer may be different. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, but these are conventionally known techniques. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

[Rate of compound addition]
In the low retardation cellulose acylate film used in the present invention, the total amount of compounds having a molecular weight of 3000 or less is preferably 5 to 45% based on the mass of cellulose acylate. More preferably, it is 10 to 40%, and even more preferably 15 to 30%. As mentioned above, these compounds include compounds that reduce optical anisotropy, wavelength dispersion modifiers, ultraviolet inhibitors, plasticizers, deterioration inhibitors, fine particles, release agents, infrared absorbers, etc., and molecular weight For example, 3000 or less is preferable, 2000 or less is more preferable, and 1000 or less is more preferable. When the total amount of these compounds is less than 5% by mass, the properties of cellulose acylate alone are likely to be produced, and there are problems such as that the optical performance and physical strength are likely to vary with changes in temperature and humidity. . If the total amount of these compounds exceeds 45% by mass, the compound will exceed the limit of compatibility in the cellulose acylate film, causing problems such as precipitation on the film surface and clouding of the film (crying out of the film). It becomes easy.

[Organic solvent for cellulose acylate solution]
In the present invention, it is preferable to produce a low retardation cellulose acylate film by a solvent cast method, and the film is produced using a solution (dope) in which cellulose acylate is dissolved in an organic solvent. The organic solvent preferably used as the main solvent in the present invention is preferably a solvent selected from esters, ketones, ethers having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 7 carbon atoms. Esters, ketones and ethers may have a cyclic structure. A compound having two or more functional groups of an ester, a ketone and an ether (that is, —O—, —CO— and —COO—) can also be used as a main solvent. It may have a functional group. In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

  As described above, for the low retardation cellulose acylate film used in the present invention, a chlorinated halogenated hydrocarbon may be used as a main solvent, and it is described in JIII Journal of Technical Disclosure 2001-1745 (pages 12-16). As described above, a non-chlorine solvent may be used as the main solvent, and is not particularly limited.

  In addition, the low-retardation cellulose acylate film-forming solution used in the present invention and the solvent used are disclosed in the following published patent gazettes, including their dissolution methods, and are preferred embodiments. They are, for example, JP 2000-95876, JP 12-95877, JP 10-324774, JP 8-152514, JP 10-330538, JP 9-95538, JP 9-95557, JP 10-10. -235664, JP-A-12-63534, JP-A-11-21379, JP-A-10-182853, JP-A-10-278056, JP-A-10-279702, JP-A-10-323853, JP-A-10-237186, JP-A-11-60807. JP-A-11-152342, JP-A-11-292988, JP-A-11-60752, JP-A-11-60752, and the like. According to these publications, not only the solvent suitable for the low-retardation cellulose acylate film forming solution used in the present invention, but also the physical properties of the solution and coexisting substances to be coexisted are described, which is a preferred embodiment in the present invention.

[Manufacturing process of low retardation cellulose acylate film]
[Dissolution process]
Preparation of the low-retardation cellulose acylate solution (dope) used in the present invention is not particularly limited, and may be performed at room temperature or further by a cooling dissolution method or a high temperature dissolution method, or a combination thereof. . Regarding the preparation of the low-retardation cellulose acylate solution in the present invention, as well as the solution concentration and filtration steps involved in the dissolution step, the Technical Report of the Society of Invention (Publication No. 2001-1745, published on March 15, 2001, The manufacturing process described in detail on pages 22 to 25 by the Japan Institute of Invention is preferably used.

(Transparency of dope solution)
The dope transparency of the cellulose acylate solution is preferably 85% or more. More preferably, it is 88% or more, and more preferably 90% or more. In the present invention, it was confirmed that various additives were sufficiently dissolved in the cellulose acylate dope solution. As a specific method for calculating the dope transparency, the dope solution was poured into a 1 cm square glass cell, and the absorbance at 550 nm was measured with a spectrophotometer (UV-3150, Shimadzu Corporation). Only the solvent was measured in advance as a blank, and the transparency of the cellulose acylate solution was calculated from the ratio with the absorbance of the blank.

[Casting, drying, winding process]
Next, a method for producing a film using the cellulose acylate solution in the present invention will be described. As a method and equipment for producing a low retardation cellulose acylate film used in the present invention, a solution casting film forming method and a solution casting film forming apparatus used for producing a conventional cellulose triacetate film are used. The dope (cellulose acylate solution) prepared from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation. The dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations. The dry-dried dope film (also referred to as web) is peeled off from the metal support at a peeling point that is uniformly cast on the metal support and substantially rounds the metal support. The both ends of the obtained web are sandwiched between clips, transported by a tenter while holding the width and dried, and then the obtained film is mechanically transported by a roll group of a drying device, dried, and then rolled by a winder Wind up to a predetermined length. The combination of the tenter and the roll group dryer varies depending on the purpose. The functional film in the present invention can also be used as a functional protective film that is an optical member for an electronic display. In this case, in the solution casting film forming method, in addition to the solution casting film forming apparatus, the subbing is performed. In many cases, a coating apparatus is added for surface processing of a film such as a layer, an antistatic layer, an antihalation layer, or a protective layer. These are described in detail on pages 25-30 in the Japan Society for Invention and Innovation Technical Report (Public Technical Number 2001-1745, issued on March 15, 2001, Japan Society for Invention). Including), metal support, drying, peeling and the like, and can be preferably used in the present invention.
Further, the thickness of the low retardation cellulose acylate film is preferably 10 to 120 μm, more preferably 20 to 100 μm, and further preferably 30 to 90 μm.

[Change in optical performance of film after high humidity treatment]
[Physical property evaluation of cellulose acylate film]
Regarding the change in the optical performance due to the environmental change of the low retardation cellulose acylate film used in the present invention, it is preferable that the amount of change in Re and Rth of the film treated at 60 ° C. and 90% RH for 240 hours is 15 nm or less. More preferably, it is 12 nm or less, and more preferably 10 nm or less.
[Change in optical performance of film after high temperature treatment]
Further, it is desirable that the amount of change in Re and Rth of the film treated at 80 ° C. for 240 hours is 15 nm or less. More preferably, it is 12 nm or less, and more preferably 10 nm or less.
[Compound volatilization after film heat treatment]
A compound that lowers Rth and a compound that lowers ΔRth, which can be preferably used in the low retardation cellulose acylate film used in the present invention, have a volatilization amount of a compound from a film treated at 80 ° C. for 240 hours. It should be less than 30%. More preferably, it is 25% or less, and more preferably 20% or less.
The amount of volatilization from the film was determined by dissolving the film treated at 80 ° C. for 240 hours and the untreated film in a solvent, detecting the compound by high performance liquid chromatography, and determining the peak area of the compound in the film The amount was calculated by the following formula.
Volatilization amount (%) = {(remaining compound amount in untreated product) − (remaining compound amount in treated product)} / (remaining compound amount in untreated product) × 100

[Glass Transition Temperature Tg of Film]
The glass transition temperature Tg of the low retardation cellulose acylate film used in the present invention is preferably 80 to 165 ° C. From the viewpoint of heat resistance, Tg is more preferably 100 to 160 ° C, and particularly preferably 110 to 150 ° C. The glass transition temperature Tg is measured with a differential scanning calorimeter (DSC2910, T.A. Instrument) measuring 10 mg of a cellulose acylate film sample from room temperature to 200 ° C. at a heating / cooling rate of 5 ° C./min. The glass transition temperature Tg was calculated.

[Haze of film]
The haze of the low retardation cellulose acylate film used in the present invention is preferably 0.01 to 2.0%. More preferably, it is 0.05 to 1.5%, and more preferably 0.1 to 1.0%. As an optical film, the transparency of the film is important. The haze was measured according to JIS K-6714 using a low-retardation cellulose acylate film sample 40 mm × 80 mm with a haze meter (HGM-2DP, Suga Test Instruments) at 25 ° C. and 60% RH.

[Humidity dependency of Re and Rth of film]
It is preferable that both the retardation Re on the front surface of the low retardation cellulose acylate film used in the present invention and the retardation Rth in the film thickness direction are small in change due to humidity. Specifically, the difference ΔRth (= Rth10% RH−Rth80% RH) between the Rth value at 25 ° C. and 10% RH and the Rth value at 25 ° C. and 80% RH at a wavelength of 630 nm is preferably 0 to 50 nm. More preferably, it is 0-40 nm, More preferably, it is 0-35 nm. The difference ΔRe (= Re10% RH−Re80% RH) between the Re value at 25 ° C. and 10% RH and the Re value at 25 ° C. and 80% RH is preferably 0 to 15 nm. More preferably, it is 0-20 nm, More preferably, it is 0-10 nm.

[Equilibrium moisture content of film]
The equilibrium moisture content of the low-retardation cellulose acylate film used in the present invention is not limited to the film thickness so as not to impair the adhesion with a water-soluble polymer such as polyvinyl alcohol when used as a protective film for a polarizing plate. It is preferable that the equilibrium water content at 25 ° C. and 80% RH is 0 to 4%. It is more preferably 0.1 to 3.5%, and particularly preferably 1 to 3%. An equilibrium moisture content of 4% or more is not preferable because the dependency of retardation due to humidity change becomes too large.
The moisture content was measured by measuring a low-retardation cellulose acylate film sample 7 mm × 35 mm by a Karl Fischer method using a moisture meter and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). . The moisture content (g) was calculated by dividing by the sample mass (g).

[Changes in film dimensions]
The dimensional stability of the low-retardation cellulose acylate film used in the present invention is such that the dimensional change rate after standing for 24 hours at 60 ° C. and 90% RH (high humidity) and 90 ° C. and 5% RH. It is preferable that the dimensional change rate after standing for 24 hours under the conditions (high temperature) is 0.5% or less. More preferably, it is 0.3% or less, and even more preferably, it is 0.15% or less.
As a specific measurement method, two low-retardation cellulose acylate film samples 30 mm × 120 mm were prepared, conditioned at 25 ° C. and 60% RH for 24 hours, and with an automatic pin gauge (Shinto Kagaku Co., Ltd.). , 6 mmφ holes were opened at both ends at an interval of 100 mm to obtain the original size (L0) of the punch interval. Punch interval size (L1) after one sample was treated at 60 ° C. and 90% RH for 24 hours, punch after one sample was treated at 90 ° C. and 5% RH for 24 hours The spacing dimension (L2) was measured. Measurement was made to a minimum scale of 1/1000 mm at all intervals. Dimensional change rate of 60 ° C. and 90% RH (high humidity) = {| L0−L1 | / L0} × 100, Dimensional change rate of 90 ° C. and 5% RH (high temperature) = {| L0−L2 | / The dimensional change rate was determined as L0} × 100.

[Elastic modulus of film]
(Elastic modulus)
The elastic modulus of the low retardation cellulose acylate film used in the present invention is preferably 200 to 500 kgf / mm ² (1.96 to 4.90 GPa). More preferably, it is 240-470 kgf / mm < ² > (2.35-4.61 GPa), More preferably, it is 270-440 kgf / mm < ² > (2.65-4.31 GPa). As a specific measurement method, Toyo Baldwin Universal Tensile Tester STM T50BP was used to measure the stress at 0.5% elongation in a 23 ° C, 70% atmosphere at a pulling rate of 10% / min to obtain the elastic modulus. It was.

[Photoelastic coefficient of film]
(Photoelastic coefficient)
The photoelastic coefficient of the low retardation cellulose acylate film used in the present invention is preferably 50 × 10 ⁻¹³ cm ² / dyne (5 × 10 ⁻¹³ N / m ² ) or less. More preferably, it is 30 × 10 ⁻¹³ cm ² / dyne (3 × 10 ⁻¹³ N / m ² ) or less, and 20 × 10 ⁻¹³ cm ² / dyne (2 × 10 ⁻¹³ N / m ² ) or less. More preferably it is. As a specific measurement method, a tensile stress is applied to the long axis direction of a 12 mm × 120 mm low retardation cellulose acylate film sample, and the retardation at that time is measured with an ellipsometer (M150, JASCO Corporation). The photoelastic coefficient was calculated from the amount of change in retardation with respect to stress.

[Detection of front retardation before and after stretching, detection of slow axis]
100 mm in the longitudinal direction and 100 mm in the width direction were cut out from the roll-shaped film sample, and stretched in the machine transport direction (MD direction) or in the vertical direction (TD direction) using a fixed uniaxial stretching machine at a temperature of 140 ° C. The front retardation Re of each sample before and after stretching was measured using an automatic birefringence meter KOBRA21ADH. The detection of the slow axis was determined from the orientation angle obtained during the retardation measurement. The low retardation cellulose acylate film preferably has a small change in Re by stretching. Specifically, the front retardation (nm) and Re (0) of a film obtained by stretching Re (n) by n (%) are stretched. It is preferable to have | Re (n) −Re (0) | /n≦1.0 when the front retardation (nm) of the film that has not been applied is | Re (n) −Re (0) | /N≦0.3 or less is more preferable.

[Direction with slow axis]
When the low retardation cellulose acylate film used in the present invention is used as a protective film for a polarizing film, since the polarizing film has an absorption axis in the machine transport direction (MD direction), the slow axis of the cellulose acylate film is MD direction. It is desirable to be in the vicinity or in the vicinity of the TD direction. Light leakage and color change can be reduced by making the slow axis parallel or orthogonal to the polarizing film. “Near” means that the slow axis and the MD or TD direction are in the range of 0 to 10 °, preferably 0 to 5 °.

[Cellulose acylate film with positive intrinsic birefringence]
The low retardation cellulose acylate film used in the present invention has a large front retardation Re when stretched in a direction having a slow axis in the film plane, and a front surface when stretched in a direction perpendicular to the direction having a slow axis. The retardation Re may be small. This indicates that the intrinsic birefringence is positive, and it is effective to stretch in the direction perpendicular to the slow axis in order to cancel the Re developed in the film. As this method, for example, when the film has a slow axis in the MD direction, the front Re can be reduced by using tenter stretching in a direction perpendicular to the MD (TD direction). As an opposite example, if the TD direction has a slow axis, the front Re can be reduced by increasing the tension of the transport roll parallel to the MD direction and stretching.

[Cellulose acylate film with negative intrinsic birefringence]
The low retardation cellulose acylate film used in the present invention has a small front retardation Re when stretched in a direction having a slow axis, and a large front retardation Re when stretched in a direction perpendicular to the direction having a slow axis. Sometimes it becomes. This indicates that the intrinsic birefringence is negative, and it is effective to stretch the film in the same direction as the slow axis in order to cancel the Re developed in the film. As this method, for example, when the film has a slow axis in the MD direction, it is conceivable to reduce the front surface Re by increasing the tension of the conveying roll in the MD direction and stretching. As an opposite example, when the slow axis is in the TD direction, it is conceivable to reduce the front retardation Re by using tenter stretching in the TD direction.

  [Evaluation Method of Low Retardation Cellulose Acylate Film Used in the Present Invention] In evaluating the low retardation cellulose acylate film used in the present invention, measurement was performed by the following method.

(Front retardation Re, thickness direction retardation Rth)
A sample 30 mm × 40 mm was conditioned at 25 ° C. and 60% RH for 2 hours, and Re (λ) was an automatic birefringence meter KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). Measured by incidence.
Rth (λ) is the light of wavelength λnm from the direction inclined by + 40 ° with respect to the normal direction of the film, with Re (λ) and the in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). And a retardation value measured by making light of wavelength λ nm incident from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis). KOBRA 21ADH calculates based on the retardation value measured in three directions in total, the assumed value of the average refractive index, and the input film thickness value.
Here, as the assumed value of the average refractive index, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. 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),
Polystyrene (1.59)
It is. The KOBRA 21ADH calculates nx, ny, and nz by inputting these assumed values of average refractive index and film thickness. Nz = (nx-nz) / (nx-ny) is further calculated from the calculated nx, ny, and nz.

(Measurement of chromatic dispersion of Re and Rth)
A sample 30 mm × 40 mm was conditioned at 25 ° C. and 60% RH for 2 hours, and light of a wavelength of 780 nm to 380 nm was incident in the normal direction of the film in an ellipsometer M-150 (manufactured by JASCO Corporation). The wavelength dispersion of Re was measured by determining Re at the wavelength. Further, the wavelength dispersion of Rth was measured by introducing light having a wavelength of 780 to 380 nm from the direction inclined by + 40 ° with respect to the normal direction of the film with the slow axis in the plane as the tilt axis. The value and the retardation value measured by making light with a wavelength of 780 to 380 nm incident from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis were measured in a total of three directions. Based on the retardation value, it was calculated by inputting the assumed average refractive index of 1.48 and the film thickness.

(Transmittance)
The transmittance of visible light (615 nm) was measured on a 20 mm × 70 mm sample at 25 ° C. and 60% RH with a transparency measuring instrument (AKA phototube colorimeter, KOTAKI Corporation).

[Film surface properties]
The surface of the low retardation cellulose acylate film used in the present invention has an arithmetic average roughness (Ra) of surface irregularities of the film based on JISB0601-1994 of 0.1 μm or less and a maximum height (Ry) of 0.1. It is preferably 5 μm or less. Preferably, the arithmetic average roughness (Ra) is 0.05 μm or less, and the maximum height (Ry) is 0.2 μm or less. The concave and convex shapes on the film surface can be evaluated by an atomic force microscope (AFM).

[In-plane variation of retardation of cellulose acylate film]
The low retardation cellulose acylate film used in the present invention preferably satisfies the following formula.
| Re _(MAX) −Re _(MIN) | ≦ 3 and | Rth _(MAX) −Rth _(MIN) | ≦ 5
[In the formula, Re _(MAX) and Rth _(MAX) are the maximum retardation values of 1 m square film cut out arbitrarily, and Re _(MIN) and Rth _(MIN) are the minimum retardation values. ]

[Retention of film]
In the low retardation cellulose acylate film used in the present invention, the retention of various compounds added to the film is required. Specifically, the mass change of the film when the low retardation cellulose acylate film is allowed to stand for 48 hours under conditions of 80 ° C. and 90% RH is preferably 0 to 5%. More preferably, it is 0 to 3%, and still more preferably 0 to 2%.
<Reservation evaluation method>
The sample was cut to a size of 10 cm × 10 cm, and the mass after being allowed to stand for 24 hours in an atmosphere of 23 ° C. and 55% RH was measured, and left for 48 hours under the conditions of 80 ± 5 ° C. and 90 ± 10% RH. . The surface of the sample after the treatment was lightly wiped, the mass after standing for 1 day at 23 ° C. and 55% RH was measured, and the retention was calculated by the following method.
Retention property (mass%) = {(mass before standing−mass after standing) / mass before standing} × 100

[Mechanical properties of film]
(curl)
The curl value in the width direction of the low retardation cellulose acylate film used in the present invention is preferably −10 / m to + 10 / m. For the low retardation cellulose acylate film used in the present invention, the surface treatment described later, the rubbing treatment when applying the optically anisotropic layer, the alignment film, the coating and bonding of the optically anisotropic layer, etc. When the curling value in the width direction of the low retardation cellulose acylate film used in the present invention is outside the above range, the handling of the film may be hindered and the film may be cut. In addition, the film is strongly in contact with the transport roll at the edge and center of the film, so it is easy to generate dust, and foreign matter adheres to the film. May exceed the value. Further, by setting the curl in the above-mentioned range, it is possible to reduce color spot failures that are likely to occur when the optically anisotropic layer is installed, and it is possible to prevent bubbles from entering when the polarizing film is bonded, which is preferable.
The curl value can be measured according to a measurement method (ANSI / ASCPH1.29-1985) defined by the American National Standards Institute.

(Tear strength)
In the tear strength (Elmendorf tear method) based on the tear test method of JISK7128-2: 1998, 2 g or more is preferable when the film thickness of the low retardation cellulose acylate film used in the present invention is in the range of 20 to 80 μm. More preferably, it is 5-25g, Furthermore, it is 6-25g. Moreover, 8 g or more is preferable at 60 micrometer conversion, More preferably, it is 8-15g. Specifically, it can be measured using a light load tear strength tester after conditioning a sample piece of 50 mm × 64 mm under the conditions of 25 ° C. and 65% RH for 2 hours.

[Residual solvent amount of film]
It is preferable to dry on the conditions that the amount of residual solvents with respect to the low retardation cellulose acylate film used by this invention is the range of 0.01-1.5 mass%. More preferably, it is 0.01-1.0 mass%. Curling can be suppressed by setting the residual solvent amount to 1.5% by mass or less. More preferably, it is 1.0 mass% or less. This is presumably because free deposition is reduced by reducing the amount of residual solvent during film formation by the above-described solvent casting method.

[Hygroscopic expansion coefficient of film]
The hygroscopic expansion coefficient of the low retardation cellulose acylate film used in the present invention is preferably 30 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is preferably 15 × 10 ⁻⁵ /% RH or less, and more preferably 10 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is preferably small, but usually it is 1.0 × 10 ⁻⁵ /% RH or more. The hygroscopic expansion coefficient indicates the amount of change in the length of the sample when the relative humidity is changed at a constant temperature. By adjusting the coefficient of hygroscopic expansion, when the cellulose acylate film is used as an optical compensation film support, while maintaining the optical compensation function of the optical compensation film, the frame-shaped transmittance increases, that is, light leakage due to distortion occurs. Can be prevented.

[Light resistance]
As an index of light durability of the low retardation cellulose acylate film used in the present invention, it is preferable that the color difference ΔE ^* ab of the film irradiated with super xenon light for 240 hours is 20 or less. More preferably, it is 18 or less, and more preferably 15 or less. The color difference was measured using UV3100 (manufactured by Shimadzu Corporation). The measurement was carried out by adjusting the film to 25 ° C. and 60% RH for 2 hours or more, and then measuring the color of the film before irradiation with xenon light to determine initial values (L0 ^* , a0 ^* , b0 ^* ). Thereafter, the film alone was irradiated with xenon light for 240 hours under conditions of 150 W / m ² , 60 ° C. and 50% RH with a Super Xenon Weather Meter SX-75 (manufactured by Suga Test Instruments Co., Ltd.). After the elapse of a predetermined time, the film was taken out from the thermostat, adjusted to 25 ° C. and 60% RH for 2 hours, and then subjected to color measurement again to obtain values after irradiation (L1 ^* , a1 ^* , b1 ^* ). . From these, the color difference ΔE ^* ab = ((L0 ^* −L1 ^* ) ² + (a0 ^* −a1 ^* ) ² + (b0 ^* −b1 ^* ) ² ) ^0.5 was obtained.

[surface treatment]
The cellulose acylate film can achieve improved adhesion between the cellulose acylate film and each functional layer (for example, the undercoat layer and the back layer) by optionally performing a surface treatment. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr (0.133 to 2660 Pa), and plasma treatment under atmospheric pressure is also preferable. Examples of the plasma-excitable gas that is plasma-excited under the above conditions include chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, and tetrafluoromethane, and mixtures thereof. Details of these are described in detail in pages 30 to 32 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention), and are preferably used in the present invention. be able to.

[Contact angle of film surface by alkali saponification]
Alkali saponification is one effective means of surface treatment when the low retardation cellulose acylate film used in the present invention is used as a protective film for a polarizing plate. In this case, the contact angle on the film surface after the alkali saponification treatment is preferably 55 ° or less. More preferably, it is 50 ° or less, and more preferably 45 ° or less. The contact angle evaluation method can be used as an evaluation of hydrophilicity / hydrophobicity by an ordinary method in which a water droplet having a diameter of 3 mm is dropped on the surface of the film after the alkali saponification treatment and the angle formed by the film surface and the water droplet is determined.

Note that an antiglare layer, an antireflection layer, or both of them may be provided on the cured film of the polarizing plate of the present invention.
The antireflection layer is formed by laminating transparent thin films of inorganic compounds (metal oxides, etc.) having different refractive indexes to form a multilayer film; thin films formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Forming method: After forming a colloidal metal oxide particle film by a sol / gel method of a metal compound such as a metal alkoxide, post-treatment (ultraviolet irradiation: JP-A-9-157855, plasma treatment: JP-A-2002-327310) ) To form a thin film. Further, as a method for forming an antireflection layer having high productivity, various proposals have been made, such as a method for forming an antireflection layer by laminating and coating a thin film composition in which inorganic particles are dispersed in a matrix. Moreover, the antireflection layer which consists of the antireflection layer which provided the anti-glare property in which the surface of the uppermost layer has the shape of a fine unevenness | corrugation to the antireflection film by this application | coating is also mentioned.

The manufacturing method of the polarizing plate of this invention is not specifically limited, It can manufacture by a general method. The polarizing plate of the present invention has a functional film comprising a transparent base film F on one side of a polarizer and a cured film and a cellulose acylate film or a transparent base film F on the other side. There is a method in which the obtained transparent substrate film F (low retardation cellulose acylate film) or cellulose acylate film is subjected to alkali treatment and bonded to the polarizing film using an adhesive. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed.
Examples of the adhesive used to bond the alkali (saponified) treated surface and the polarizing film include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, and vinyl latexes such as butyl acrylate. .

The polarizing film is preferably a coating type polarizing film typified by Optiva, or a polarizing film made of a binder and iodine or a dichroic dye.
Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal.
Currently, a general-purpose polarizing film is produced by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing the iodine or dichroic dye to penetrate into the binder. Is common. In general-purpose polarizing films, iodine or dichroic dye is distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time.

The binder of the polarizing film may be cross-linked. As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change.
Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent. It can be formed by cross-linking between binders by introducing a bonding group derived from the cross-linking agent between binders using a cross-linking agent which is a compound having high reaction activity.
Crosslinking is generally carried out by applying a coating solution containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the crosslinking treatment may be performed at any stage until the final polarizing plate is obtained.

  As the binder of the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of polymers include polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, polystyrene, gelatin, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-methylolacrylamide), polyvinyltoluene, chlorosulfonated polyethylene, nitrocellulose, chlorinated Polyolefin (eg, polyvinyl chloride), polyester, polyimide, polyvinyl acetate, polyethylene, carboxymethylcellulose, polypropylene, polycarbonate and copolymers thereof (eg, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, styrene) / Vinyl toluene copolymer, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer). Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. .

The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and most preferably 95 to 100%. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.
Modified polyvinyl alcohol is obtained by introducing a modifying group into polyvinyl alcohol by copolymerization modification, chain transfer modification or block polymerization modification. In the copolymerization modification, COONa, Si (OH) ₃ , N (CH ₃ ) ₃ .Cl, C ₉ H ₁₉ COO, SO ₃ Na, C ₁₂ H ₂₅ can be introduced as modifying groups. In chain transfer modification, COONa, SH, or SC ₁₂ H ₂₅ can be introduced as a modifying group. The degree of polymerization of the modified polyvinyl alcohol is preferably 100 to 3000. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127.
Unmodified polyvinyl alcohol and alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% are particularly preferred.
Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

When a large amount of the crosslinking agent for the binder is added, the heat and humidity resistance of the polarizing film can be improved. However, when 50 mass% or more of a crosslinking agent is added to the binder, the orientation of iodine or the dichroic dye is lowered. The addition amount of the crosslinking agent is preferably 0.1 to 20% by mass, and more preferably 0.5 to 15% by mass with respect to the binder.
The binder contains some crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less in the binder, and more preferably 0.5% by mass or less. When the crosslinking agent is contained in the binder layer in an amount exceeding 1.0% by mass, there may be a problem in durability. That is, when a polarizing film having a large amount of residual crosslinking agent is incorporated in a liquid crystal display device and used for a long time or left in a high-temperature and high-humidity atmosphere for a long time, the degree of polarization may decrease. The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

  As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl). Examples of dichroic dyes include C.I. I. Direct Yellow 12, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Direct Violet 48, C.I. I. Direct Blue 67, C.I. I. Direct Blue 90, C.I. I. Direct Green 59, C.I. I. Acid Red 37 is included. As for the dichroic dyes, those described in JP-A-1-161202, 1-172906, 1-172907, 1-183602, 1-248105, 1-265205, 7-261024 are used. There are descriptions in each publication. The dichroic dye is used as a free acid or an alkali metal salt, ammonium salt or amine salt. By blending two or more types of dichroic dyes, polarizing films having various hues can be produced. A polarizing film using a compound (pigment) that exhibits a black color when the polarization axes are orthogonal to each other, or a polarizing film or a polarizing plate in which various dichroic molecules are blended so as to exhibit a black color, have both a single-plate transmittance and a polarizability. It is excellent and preferable.

[Polarizing plate having optically anisotropic layer]
An optically anisotropic layer may be laminated on the polarizing plate of the present invention (hereinafter, the polarizing plate having the optically anisotropic layer is referred to as “optical compensation polarizing plate” in the present specification). The optical compensation polarizing plate is generally used in a liquid crystal display device and can compensate for a phase difference. When the optically anisotropic layer is mounted on the polarizing plate of the present invention, the optically anisotropic layer is laminated on the surface opposite to the side having the cured film of the polarizer. The optical compensation polarizing plate can be formed by adhering an optical compensation film obtained by laminating an optical anisotropic layer on the transparent substrate film F to a polarizer. A functional film having a cured film and a cellulose acylate film or a transparent substrate film F is laminated on the side of the polarizer opposite to the side having the optical compensation film. The optical compensation film has birefringence and is used for the purpose of removing the color of the display screen of the liquid crystal display device or improving the viewing angle characteristics. The transparent substrate film F used in the present invention has a small optical anisotropy with Re (630) and Rth (630) being 0 ≦ Re ≦ 10 nm and | Rth | ≦ 25 nm, and | Re (400) −Re ( 700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35, so that the wavelength dispersion is small, so that anisotropy does not occur and an optical anisotropic layer having birefringence is used in combination. Only the optical performance of the conductive layer can be exhibited.

Therefore, when the transparent base film F used in the present invention is used as a support for an optical compensation film of a liquid crystal display device, Re (630) and Rth (630) of the optically anisotropic layer used together are Re = 0 to 200 nm. And | Rth | = 0 to 400 nm is preferable, and any optically anisotropic layer may be used within this range. The optical performance and driving method of the liquid crystal cell of the liquid crystal display device are not limited, and any optical anisotropic layer required as an optical compensation film can be used in combination. The optically anisotropic layer used in combination may be formed from a composition containing a liquid crystalline compound or may be formed from a polymer film having birefringence.
The liquid crystal compound is preferably a discotic liquid crystal compound or a rod-like liquid crystal compound.

(General liquid crystal display device configuration)
In the present invention, the transmission axis of the polarizing plate and the slow axis of the optical compensation film may be arranged at any angle. The liquid crystal display device includes a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and at least one sheet between the liquid crystal cell and the polarizing plate. The optical compensation film is arranged.
The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

(Types of liquid crystal display devices)
The polarizing plate and the optical compensation polarizing plate of the present invention can be used for liquid crystal display devices in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroly Liquid Liquid Crystal), OCB (Optically Liquid BTS). Various display modes such as ECB (Electrically Controlled Birefringence) and HAN (Hybrid Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The functional film of the present invention is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

(Configuration of liquid crystal display device)
The polarizing plate and the optical compensation polarizing plate of the present invention are preferably used as a polarizing plate placed on the viewing side of a pair of polarizing plates placed on both sides of the liquid crystal cell, and the side having the cured film of the polarizing plate is the air interface It is preferable to mount so as to be on the side. Hereinafter, an example of the liquid crystal display device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example in which the polarizing plate of the present invention is mounted on a liquid crystal cell.
FIG. 2 is a schematic view showing an example in which the polarizing plate (optical compensation polarizing plate) of the present invention having an optically anisotropic layer is mounted on a liquid crystal cell.

  In FIG. 1, the polarizing plate 1 of the present invention is a liquid crystal cell so that it becomes a cured film 2, a cellulose acylate film 3 or a transparent substrate film F4, a polarizer 5, and a transparent substrate F4 in order from the air interface side (viewing side). 6 is arranged. The transparent substrate film F4, the liquid crystal cell, and 6 are attached via an adhesive layer (not shown). On the other hand, when using the optical compensation polarizing plate 7 of the present invention, the cured film 2, the cellulose acylate film 3 or the transparent substrate film F4, the polarizer 5, the transparent substrate F4, in order from the air interface side (viewing side), It arrange | positions at the liquid crystal cell 6 so that it may become the optically anisotropic layer 8. FIG. By making the side having the cured film of the polarizing plate of the present invention the air interface side, it is excellent in scratch resistance and low moisture permeability, can prevent deterioration of the polarizer and can maintain high-quality display performance for a long time. . On the other hand, as a pair of polarizing plates, a polarizing plate in which a cellulose acylate film is laminated as a protective film on both surfaces of a polarizer used in the polarizing plate of the present invention can be used.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not limited to the following example.

(Preparation of cellulose acylate film)
(Preparation of cellulose acetate solution)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution D.

(Cellulose acetate solution D composition)
Cellulose acetate having an acyl substitution degree of 2.86 100.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass

(Preparation of matting agent fine particle solution)
20 parts by mass of silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) and 80 parts by mass of methanol were thoroughly mixed for 30 minutes to obtain a silica particle dispersion. This dispersion was put into a disperser together with the following composition, and further stirred for 30 minutes or more to dissolve each component to prepare a matting agent fine particle solution.

(Matting agent fine particle solution composition)
Silica particle dispersion liquid having an average particle diameter of 16 nm 10.0 parts by mass Methylene chloride (first solvent) 76.3 parts by mass Methanol (second solvent) 3.4 parts by mass Cellulose acetate solution D 10.3 parts by mass

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution. The compounds shown in Table 1 below were used for the compounds and wavelength dispersion adjusting agents that reduce the optical anisotropy.

(Additive solution composition)
Compound for reducing optical anisotropy 49.3 parts by weight Wavelength dispersion adjusting agent 7.6 parts by weight Methylene chloride (first solvent) 58.4 parts by weight Methanol (second solvent) 8.7 parts by weight Cellulose acetate solution D 12.8 parts by mass

(Preparation of cellulose acetate film sample 115)
94.6 parts by mass of the cellulose acetate solution D, 1.3 parts by mass of the matting agent fine particle solution, and 4.1 parts by mass of the additive solution were mixed after filtration, and cast using a band casting machine. The mass ratios of the compound for reducing optical anisotropy and the wavelength dispersion adjusting agent in the above composition to the solid content of cellulose acetate were 12% and 1.8%, respectively. The film was peeled from the band with a residual solvent amount of 30% and dried at 140 ° C. for 40 minutes to produce a cellulose acetate film. The resulting cellulose acetate film had a residual solvent amount of 0.2% and a film thickness of 80 μm.

(Production of cellulose acetate film samples 008 to 011, 116 to 117)
Cellulose acetate film samples 008 to 011 and 116 to 117 were produced in the same manner except that the types and amounts of the compound for reducing optical anisotropy in the additive solution and the wavelength dispersion adjusting agent were changed to those shown in Table 1. .

<White turbidity of film>
In Table 1, the cloudiness of the cellulose acetate film was examined visually.

(Preparation of cured film)
Compound M-5 4.85 g
(Kyarad R-684, manufactured by Nippon Kayaku Co., Ltd.)
MEK (methyl ethyl ketone) 4.50g
Cyclohexanone 0.50g
Photoradical polymerization initiator 0.15g
(Irgacure 907, manufactured by Ciba Geigy)
Were mixed and stirred to obtain a curable composition.

(Production of functional film)
The said curable composition was apply | coated to the cellulose acetate film samples 115-117 with # 6 bar. After drying at 70 ° C. for 2 minutes, ultraviolet rays were irradiated (500 mJ / cm ² ) in a nitrogen atmosphere to prepare Samples 115A to 117A.
The cured film thickness was 4.5 μm.

(Moisture permeability of functional film)
Hereinafter, the moisture permeability of the produced samples 008 to 011 and 115A to 117A is shown in Table 2. The moisture permeability is a value determined according to JIS-Z-0208 (60 ° C., 95% relative humidity).

(Preparation of polarizing plate)
[Saponification]
A 1.5 mol / L sodium hydroxide aqueous solution was prepared and kept at 50 ° C. A 0.005 mol / L dilute sulfuric acid aqueous solution was also prepared.
The samples 008 to 011 and the samples 115A to 117A were immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the above-mentioned dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution and sufficiently dried at 100 ° C. In this way, a saponification film was obtained.

[Preparation of polarizing film]
(Polyvinyl alcohol casting)
Polyvinyl alcohol (PVA) having an average polymerization degree of 4000 and a saponification degree of 99.8 mol% was dissolved in water to obtain a 4.0% by mass aqueous solution. This solution was cast and dried, peeled off from the band, and an unstretched polyvinyl alcohol film was obtained.

(Iodine impregnation)
The unstretched polyvinyl alcohol film is immersed in an aqueous solution of 2.0 g / L of iodine and 4.0 g / L of potassium iodide at 25 ° C. for 240 seconds, and further in an aqueous solution of boric acid 10 g / L for 60 seconds at 25 ° C. After soaking, it was washed with water at 20 ° C. for 10 seconds in a washing tank.

(Stretching)
The iodine impregnated film was stretched 5.3 times at 80 ° C. without being dried. After stretching, the film was dried at 80 ° C. for 5 minutes to obtain a long polarizing film. The thickness was 20 μm.

[Attaching the protective film for polarizing plate]
The saponification film was attached to both sides of the polarizing film by using a 3% by weight aqueous solution of polyvinyl alcohol “PVA-117H” {manufactured by Kuraray Co., Ltd.} as an adhesive. The stacking order is as follows.
Comparative Example 1 Sample 008 / Polarized Film / Sample 008 / Glass Plate Comparative Example 2 Sample 009 / Polarized Film / Sample 009 / Glass Plate Comparative Example 3 Sample 010 / Polarized Film / Sample 010 / Glass Plate Comparative Example 4 Sample 011 / Polarized Film / Sample 011 / Glass plate example 1 Sample 115A / Polarized film / Sample 115 / Glass plate example 2 Sample 116A / Polarized film / Sample 116 / Glass plate example 3 Sample 117A / Polarized film / Sample 117 / Glass plate Sample In 115A to 117A, the adhesive surface with the polarizing film was on the cellulose acetate film side where no cured film was formed. This polarizing plate was adhered to a glass plate using an adhesive to prepare a test sample.

<Measurement of degree of polarization>
The polarizing plate obtained as described above was allowed to stand for 1000 hours in an environment of 60 ° C. and 95% RH, and then the degree of polarization was measured. The degree of polarization is obtained from the following mathematical formula (3). (Wavelength 550nm)

<Evaluation of degree of polarization>
○: No problem with polarization degree of 99% or more.
Δ: The degree of polarization is 98% or more and less than 99%, and there is no practical problem.
X: The degree of polarization is less than 98%, which is a problem.

<Evaluation of leaking light>
The polarizing plate obtained as described above was allowed to stand for 1000 hours in an environment of 60 ° C. and 95% RH, and then observed under crossed Nicols to measure the leakage of light at the peripheral portion (note that the size of the polarizing plate is 150 mm × 150 mm).
Leakage light = Peripheral maximum transmittance (wavelength 550nm) / Center transmittance (wavelength 550nm)
◯: No problem with leaking light less than 2.
(Triangle | delta): There is no problem practically with leak light 2-3.
X: Leakage light exceeds 3 and is a problem.

In the comparative example, the degree of polarization decreased and the display contrast decreased due to the large moisture permeability. In addition, the leakage light is large, and when it is applied to a liquid crystal display device, light leakage at the periphery of the LCD tends to occur.
On the other hand, the polarizing plate of the present invention has a low water vapor transmission rate, and even when placed under high humidity for a long period of time, no decrease in the degree of polarization and leakage light were observed.
Furthermore, the polarizing plate of the present invention having a cellulose acylate film having particularly small Re and Rth and small wavelength dispersion had good display color.

FIG. 1 is a schematic view showing an example in which the polarizing plate of the present invention is mounted on a liquid crystal cell. FIG. 2 is a schematic view showing an example in which the polarizing plate (optical compensation polarizing plate) of the present invention having an optically anisotropic layer is mounted on a liquid crystal cell.

Explanation of symbols

1 Polarizing plate 2 Cured film 3 Cellulose acylate film 4 Transparent substrate film F
5 Polarizer 6 Liquid crystal cell 7 Optical compensation polarizing plate 8 Optical anisotropic layer

Claims (12)

A polarizing plate comprising at least a cured film, a cellulose acylate film or a transparent substrate film F, a polarizer, and a transparent substrate film F in this order, and the cured film and the cellulose acylate arranged on one side of the polarizer Permeability measured in an atmosphere of 60 ° C. and 95% relative humidity of a laminate comprising a rate film or a laminate comprising a cured film and a transparent substrate film F in accordance with JIS-Z-0208. A polarizing plate having a humidity of 1000 g / m ² · day or less.
However, the transparent substrate film F is a cellulose acylate film in which Re ₍ λ ₎ and Rth ₍ λ ₎ satisfy the following formulas (I) and (II).
(I) 0 ≦ Re (630) ≦ 10 and | Rth (630) | ≦ 25
(II) | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[In the formula, Re ₍ λ ₎ is a front retardation value (unit: nm) at a wavelength λnm, and Rth ₍ λ ₎ is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. ]   When the transparent substrate film F is a cellulose acylate having an acyl substitution degree of 2.85 to 3.00, at least one compound that reduces Re (λ) and Rth (λ) is added to the cellulose acylate solid content. The polarizing plate according to claim 1, wherein the polarizing plate is obtained by adding at a ratio of 0.01 to 30 mass%.   The transparent substrate film F reduces at least one of compounds in which Re (λ) and Rth (λ) are reduced and the octanol-water partition coefficient (Log P value) is 0 to 7, and cellulose acylate solid content The polarizing plate according to claim 1, wherein the polarizing plate is obtained by adding 0.01 to 30% by mass with respect to the polarizing plate. A compound that reduces Re (λ) and Rth (λ) and has an octanol-water partition coefficient (Log P value) of 0 to 7 is any of the following general formulas (13), (18), and (19). The polarizing plate according to claim 3, wherein the polarizing plate is represented by:

[In General Formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. However, the total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more. ]

[In General Formula (18), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. ]

[In the general formula (19), R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group or an aryl group. ]   The transparent base film F contains at least one compound that lowers | Re (400) -Re (700) | and | Rth (400) -Rth (700) | with respect to the cellulose acylate solid content. The polarizing plate according to claim 1, wherein the polarizing plate is contained at a ratio of 0.01 to 30% by mass.   The film thickness of the said transparent base film F is 10-120 micrometers, The polarizing plate in any one of Claims 1-5 characterized by the above-mentioned.   The polarizing plate according to claim 1, wherein the cured film has a thickness of 1 to 10 μm.   The polarizing plate according to claim 7, wherein the cured film has a thickness of 1 to 5 μm. The cured film contains at least one compound selected from a compound represented by the following general formula (1) and a compound represented by the following general formula (2) as a polymerization unit. The polarizing plate according to any one of 8.
General formula (1)

(In general formula (1), R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 is an alkylene group or alkylene oxide group having 1 to 5 carbon atoms, and R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. , N represents an integer of 1 or 2)
General formula (2)

(In the general formula (2), R1, R3 and n have the same meaning as in the general formula (1)).   It has an optical compensation layer, The polarizing plate in any one of Claims 1-9 characterized by the above-mentioned.   A liquid crystal display device comprising the polarizing plate according to claim 1.   A liquid crystal display device having a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein the polarizing plate disposed on the viewing side is the polarizing plate according to claim 1, The polarizing plate or the optical compensation polarizing plate has a transparent substrate film F, a polarizer, a cellulose acylate film or a transparent substrate film F, and a cured film in this order from the liquid crystal cell side. apparatus.

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