JP2014206716A - Va (vertical alignment) mode liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a VA mode liquid crystal display device which hardly causes irregularity in a moisture-heat environment and has excellent front contrast and viewing angle performance.SOLUTION: The VA mode liquid crystal display device comprises a pair of polarizing plates with absorption axes orthogonal to each other with a liquid crystal cell being interposed therebetween. The polarizing plate in a viewing side includes, successively from the liquid crystal cell side, an optical compensation layer, a polarizer and a polarizing plate protective film; and the optical compensation layer has a thickness of 10 μm or less and has Rth(550) of 35 nm to 220 nm. The polarizing plate in a backlight side includes, successively from the liquid crystal cell side, an optical compensate layer, a polarizer and a polarizing plate protective film; and the optical compensation layer has a thickness of 10 μm to 60 μm and satisfies expressions (1):30 nm≤Re(550)≤200 nm and (2):50 nm≤Rth(550)≤400 nm.

Description

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

  In recent years, liquid crystal display devices have been made thinner in order to expand display applications and reduce costs. Further, it is generally known that a VA mode liquid crystal display device is superior in front contrast as compared with a TN mode or IPS mode liquid crystal display device. However, with the recent improvement in image quality, further improvement in front contrast has been demanded. Furthermore, there is a demand for reduction of light leakage and tint when observed from an oblique direction during black display.

  As a technique for improving the image quality of a VA mode liquid crystal display device, Patent Document 1 discloses a method in which an optically anisotropic layer formed from discotic liquid crystalline molecules is directly provided on the surface of a polarizing film. An example discloses a method in which rod-like liquid crystal molecules are coated on disk-like liquid crystalline molecules and used in a VA mode liquid crystal display device.

Japanese Patent No. 4234960

On the other hand, with the trend of thinning liquid crystal display devices, the glass used for liquid crystal cells is becoming thinner. At this time, a member (for example, a polarizer or an optical compensation sheet) to be bonded to the liquid crystal cell is deformed in a wet and heat environment, so that the liquid crystal cell is easily warped, resulting in a problem of unevenness and deterioration of display quality. all right. In addition, in order to reduce the thickness of the liquid crystal display device, the polarizing plate itself needs to be thinned.
Here, when the technique described in Patent Document 1 was applied to reduce the thickness of the polarizing plate, it was found that there was a problem that the front contrast of the liquid crystal display device was lowered.

  The present invention is intended to solve the above-described problems, and the polarizing plate is thinned, unevenness is hardly caused in a humid heat environment, the front contrast is prevented from being lowered, and light leakage is observed when observed from an oblique direction. Another object of the present invention is to provide a VA mode liquid crystal display device capable of reducing coloring.

  As a result of intensive studies by the inventors of the present invention based on the above problems, it has been found that thinning the optical compensation layer included in the polarizing plate on the viewing side is effective in suppressing unevenness in a humid heat environment. In addition, by arranging an optical compensation layer having a predetermined thickness, Re, and Rth on the polarizing plate on the backlight side, it is possible to reduce light leakage and tinting when observed from an oblique direction without reducing the front contrast. The present inventors have found that a VA mode liquid crystal display device can be provided and have completed the present invention.

Specifically, the above problem has been solved by the following means <1>, preferably by <2> to <5>.
<1> A VA mode liquid crystal display device in which a pair of polarizing plates whose absorption axes are orthogonal to each other are disposed with a liquid crystal cell sandwiched therebetween, and the polarizing plate on the viewing side in order from the liquid crystal cell side, an optical compensation layer, a polarizer, It has a polarizing plate protective film, the thickness of the optical compensation layer is 10 μm or less, Rth (550) is 35 nm to 200 nm, and the polarizing plate on the backlight side is sequentially arranged from the liquid crystal cell side to the optical compensation layer and the polarizer. A VA mode liquid crystal display device having a polarizing plate protective film, wherein the optical compensation layer has a thickness of 10 μm to 60 μm, and satisfies the following formulas (1) and (2).
Formula (1) 30 nm ≦ Re (550) ≦ 200 nm
Formula (2) 50 nm ≦ Rth (550) ≦ 400 nm
(Re (550) represents in-plane retardation at a wavelength of 550 nm, and Rth (550) represents retardation in the thickness direction at a wavelength of 550 nm.)
<2> A VA mode liquid crystal display device in which a pair of polarizing plates whose absorption axes are orthogonal to each other are arranged with a liquid crystal cell sandwiched therebetween, and the polarizing plate on the viewing side in order from the liquid crystal cell side, an optical compensation layer, a polarizer, It has a polarizing plate protective film, the thickness of the optical compensation layer is 10 μm or less, Rth (550) is 35 nm to 220 nm, and the polarizing plate on the backlight side is arranged in order from the liquid crystal cell side to the optical compensation layer and the polarizer. A VA mode liquid crystal display device having a polarizing plate protective film, wherein the optical compensation layer has a thickness of 10 μm to 60 μm, and satisfies the following formulas (1) and (2).
Formula (1) 30 nm ≦ Re (550) ≦ 200 nm
Formula (2) 50 nm ≦ Rth (550) ≦ 400 nm
(Re (550) represents in-plane retardation at a wavelength of 550 nm, and Rth (550) represents retardation in the thickness direction at a wavelength of 550 nm.)
<3> The optical compensation layer included in the polarizing plate on the viewing side has a horizontally aligned discotic liquid crystalline compound, and is formed directly or via an alignment film on the polarizer <1> or <2 > VA mode liquid crystal display device.
<4> The VA mode liquid crystal display device according to any one of <1> to <3>, wherein the optical compensation layer included in the polarizing plate on the backlight side satisfies the following formula (3).
Formula (3) 0.5 ≦ Re (450) / Re (550) ≦ 1.0
<5> The thickness of the polarizing plate protective film contained in the polarizing plate on the backlight side is 60 μm or less, and the moisture permeability at 40 ° C. and 90% RH is 50 g / m ² · day or less. The VA mode liquid crystal display device according to any one of the above.

  According to the present invention, it has become possible to provide a VA mode liquid crystal display device that uses a thin polarizing plate, is less likely to cause unevenness in a humid heat environment, and has excellent front contrast and viewing angle performance.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

(Viewing side polarizing plate)
The viewing side polarizing plate used in the VA mode liquid crystal display device of the present invention has an optical compensation layer, a polarizer, and a polarizing plate protective film in this order from the liquid crystal cell side.
<Optical compensation layer included in viewing side polarizing plate>
The optical compensation layer included in the viewing-side polarizing plate used in the present invention has a thickness of 10 μm or less. As a result of investigations by the present inventors, it has been found that setting the film thickness of the optical compensation layer included in the viewing-side polarizing plate in the above range is effective for suppressing unevenness in a humid heat environment. When the liquid crystal display device is exposed to a humid heat environment, the viewing side polarizing plate is exposed to the external temperature and humidity environment, while the backlight side polarizing plate is covered by the housing, so that the external temperature and humidity environment is compared to the viewing side polarizing plate. Expected to be less affected. Therefore, in order to suppress unevenness in a humid heat environment, it is considered that unevenness in a humid heat environment can be suppressed by suppressing the deformation of the viewing side polarizing plate.

  Furthermore, it has been found that unevenness that occurs when the polarizer expands and contracts in a humid heat environment is suppressed as the thickness of the optical compensation layer included in the viewing side polarizing plate decreases. Without being bound by any theory, it is believed that the closer the distance between the deforming polarizer and the liquid crystal cell is, the more the warpage is suppressed and the unevenness is suppressed. The more preferable thickness of the optical compensation layer included in the recognition side polarizing plate is 5 μm or less, and more preferably 3 μm or less. Although there is no restriction | limiting in particular about a minimum, It is 0.1 micrometer or more practically.

  The retardation Rth (550) in the thickness direction at a wavelength of 550 nm of the optical compensation layer is preferably 35 nm to 220 nm. More preferably, it is 35-200 nm, More preferably, it is 50 nm-220 nm, More preferably, it is 70 nm-200 nm. The in-plane retardation Re (550) at a wavelength of 550 nm of the optical compensation layer is preferably 0 nm to 5 nm. More preferably, it is 0 nm-4 nm, More preferably, it is 0 nm-3 nm.

  The optical compensation layer may be a polymer film or a liquid crystal compound, but it preferably contains a horizontally aligned discotic liquid crystal compound because of its high optical development and thinning. The optical compensation layer containing the discotic liquid crystalline compound may be formed directly on the polarizer, or may be provided after forming an alignment film on the polarizer.

[Disc liquid crystalline compound]
Examples of discotic liquid crystal compounds include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type and phenylacetylene type macrocycles are included.
As a discotic liquid crystalline compound, a compound having liquid crystallinity in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule Is also included. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. In the optical compensation layer formed from the discotic liquid crystalline compound, the compound contained in the optical compensation layer does not necessarily need to be a discotic liquid crystalline compound. For example, a low molecular weight discotic liquid crystalline compound is formed by heat or light. Also included are compounds that have a reactive group and are consequently polymerized or crosslinked by reaction with heat and light, resulting in a high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Accordingly, the discotic liquid crystalline compound is preferably a compound represented by the following formula (I).

(I) D (-LQ) n
Where D is a discotic core; L is a divalent linking group; Q is a polymerizable group; and n is an integer from 4 to 12.
Examples of the disk-shaped core (D) of the above formula are specifically described in [0019] to [0032] of Japanese Patent No. 4084519.

In the optical compensation layer used in the present invention, two or more kinds of discotic liquid crystalline compounds may be used in combination. For example, a polymerizable discotic liquid crystalline compound and a non-polymerizable discotic liquid crystalline compound as described above can be used in combination. The non-polymerizable discotic liquid crystalline compound is preferably a compound obtained by changing the polymerizable group (Q) of the polymerizable discotic liquid crystalline compound to a hydrogen atom or an alkyl group. That is, the non-polymerizable discotic liquid crystalline compound is preferably a compound represented by the following formula (Ia).
(Ia) D (-LR) n
Where D is a discotic core; L is a divalent linking group; R is a hydrogen atom or an alkyl group; and n is an integer from 4 to 12. The example of the discotic core (D) of the formula (Ia) is the same as the example of the polymerizable discotic liquid crystalline compound except that LQ (or QL) is changed to LR (or RL). Examples of the divalent linking group (L) are the same as the examples of the polymerizable discotic liquid crystalline compound.

  In addition, the description in [0033] to [0034] of Japanese Patent No. 4084519 can be followed.

[Composition containing discotic liquid crystalline compound]
The discotic liquid crystalline compound used in the present invention may be used in a state containing other compounds as a composition. The composition containing a discotic liquid crystalline compound used in the present invention is also preferably used as a coating solution.

[solvent]
As the solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.
The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Fluorine-containing surfactant]
The composition containing the discotic liquid crystalline compound used in the present invention may contain at least one fluorine-containing surfactant in order to align the liquid crystalline compound or make the optical properties uniform in the plane. preferable. The fluorine-containing surfactant may be a low molecular compound or a high molecular compound. For example, for low molecular compounds, compounds exemplified in JP-A-2005-128050 are preferred.

  The polymer compound preferably contains a fluoroaliphatic-containing polymer containing a repeating unit represented by the following general formula (1).

In the general formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) A group represented by LQ, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, and more preferably a hydrogen atom or a group having 1 to 1 carbon atoms. 4 is an alkyl group, particularly preferably a hydrogen atom or an alkyl group having 1 or 2 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like.
The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L is a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, —PO (OR ⁵ ) —, an alkylene group, an arylene group, or a combination thereof. Represents a valent linking group. Here, R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. R ⁵ represents an alkyl group, an aryl group, or an aralkyl group.
L preferably includes a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, an alkylene group, or an arylene group, and includes —CO—, —O—, — It is particularly preferred that it contains NR ⁴ —, an alkylene group, or an arylene group.
When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Specific examples of particularly preferable alkylene groups include a methylene group, an ethylene group, a trimethylene group, a tetrabutylene group, and a hexamethylene group.
When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene groups and naphthalene groups.
When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group.
The group listed as L may have a suitable substituent. Examples of such a substituent include those similar to the substituents exemplified above as the substituents for R ^{1 to} R ³ . Although the specific structure of L is illustrated below, this invention is not limited to these specific examples.

Q is not particularly limited as long as it is a polar group having hydrogen bonding properties. Preferably, hydroxyl group, carboxyl group, salt of carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, trimethylbenzylammonium, dimethylphenyl) ammonium etc.), pyridinium salt), an amide group of the carboxylic acid (N unsubstituted bodies, N- mono-lower alkyl-substituted, or N- di-lower alkyl-substituted bodies, e.g. _{-CONH 2, -CONHCH 3, -CON (} CH 3 ₂ ), a sulfo group, a salt of a sulfo group (examples of cations forming the salt are the same as those described for the carboxyl group), a sulfonamide group (N unsubstituted, N-mono lower alkyl substituted or N-di-lower alkyl substituents such as -S _{2 NH 2, -SO 2 NHCH 3} , such as _{-SO 2 N (CH 3) 2} ), phospho group, examples of the cation forming the salt of phospho group (salt are the same as those described in the above carboxyl group), a phosphonic amide (N unsubstituted, or N- mono-lower alkyl substituted compound, for example, _{-OP (= O) (NH 2} ) 2, -OP (= O) (NHCH 3) 2 , etc.), a ureido group (-NHCONH _2), Examples thereof include an amino group (—NH ₂ , —NHCH ₃ ) which is unsubstituted or monosubstituted at the N position (wherein the lower alkyl group represents a methyl group or an ethyl group). More preferred are a hydroxyl group, a carboxyl group, a sulfo group, and a phospho group, and particularly preferred is a hydroxyl group or a carboxyl group.

  The repeating unit contained in the polymer may be one kind alone, or two or more kinds of repeating units may be present simultaneously. A repeating unit having a carboxylic acid or a repeating unit having an acrylamide group is particularly preferred.

  Further, the fluoroaliphatic-containing polymer may have one or more repeating units derived from a fluoroaliphatic group-containing monomer. Preferably, it contains a fluoroaliphatic group-containing monomer described in general formula (I) or general formula (II) of JP-A-2006-126768. Specifically, it may contain one type of repeating unit derived from a monomer selected from the monomer group described in JP-A 2006-126768 [0033] to [0044], or two or more types. You may do it.

  Further, the fluoroaliphatic-containing polymer may contain a repeating unit other than the above. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. The fluoroaliphatic polymer may contain one type of repeating unit derived from a monomer selected from the monomer group described in [0026] to [0033] of JP-A-2004-46038, You may contain more than a seed.

  Further, the fluoroaliphatic-containing polymer may contain a repeating unit derived from a monomer represented by the general formula [2] described in JP-A-2004-333852.

  The fluoroaliphatic-containing polymer may have a polymerizable group as a substituent in order to fix the alignment state of the liquid crystal compound.

  In the fluoroaliphatic group-containing polymer used in the present invention, the polymerized unit of the monomer having a fluoroaliphatic group is 25 to 99% by mass based on the total polymerized units constituting the fluoroaliphatic group-containing polymer. preferable. A more desirable ratio varies depending on the structure of the fluoroaliphatic group, and the polymerized units of the monomer represented by the general formula (I) in JP-A-2006-126768 are based on all polymerized units constituting the fluoroaliphatic-containing polymer. It is preferably 50 to 99% by mass, more preferably 60 to 97% by mass, and even more preferably 70 to 95% by mass. The polymerization unit of the monomer represented by the general formula (II) in JP-A-2006-126768 is preferably 25 to 80% by mass based on the total polymerization units constituting the fluoroaliphatic-containing polymer, 30 More preferably, it is -70 mass%, and it is still more preferable that it is 35-65 mass%. Further, two or more kinds of fluoroaliphatic group-containing monomers may be contained in one polymer, and one or more monomers each represented by the general formula (I) and one represented by the general formula (II) are used. It may be included at the same time.

  A preferred mass average molecular weight of the fluoroaliphatic-containing polymer used in the present invention is 2,000 to 100,000, more preferably 3,000 to 80,000, and still more preferably 4,000 to 60,000. 000. Here, the mass average molecular weight and the molecular weight are converted into polystyrene by GTH analyzer using a column of TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL (both trade names manufactured by Tosoh Corporation), and solvent THF and differential refractometer detection. Is the molecular weight.

  The said fluoroaliphatic content polymer used for this invention can be manufactured by a well-known and usual method. For example, it can be produced by adding a general-purpose radical polymerization initiator into an organic solvent containing a fluorine-based monomer, a monomer having a hydrogen bonding group, and the like, and polymerizing it. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition. More specifically, it is preferable to use the method described in [0035] to [0041] of JP-A-2004-46038.

[Boronic acid compounds]
When the optical compensation layer is directly formed on the polarizer included in the polarizing plate on the viewing side, a boronic acid compound can be used in order to improve the adhesion between the polarizer and the optical compensation layer.

The boronic acid compound used in the present invention represents, for example, a compound having at least one boronic acid group or boronic ester group, and a metal complex having these as a ligand, or tetracoordinate boron. A boronium ion having an atom is also represented.
The boronic acid compound used in the present invention is preferably represented by the following general formula (II), and the compound represented by the following general formula (II) will be described in detail below.

In general formula (II), R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group.
Examples of the aliphatic hydrocarbon group include a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms (for example, a methyl group, an ethyl group, an iso-propyl group, etc.), An unsubstituted cyclic alkyl group (for example, a cyclohexyl group etc.) and a C2-C20 alkenyl group (for example, a vinyl group etc.) are mentioned.
Examples of the aryl group include a substituted or unsubstituted phenyl group having 6 to 20 carbon atoms (for example, a phenyl group and a tolyl group), a substituted or unsubstituted naphthyl group having 10 to 20 carbon atoms, and the like.
The heterocyclic group is, for example, a substituted or unsubstituted 5-membered or 6-membered ring group containing at least one heteroatom (for example, nitrogen atom, oxygen atom, sulfur atom, etc.), such as pyridyl group, imidazolyl Group, furyl group, piperidyl group, morpholino group and the like.
R ¹ and R ² may be connected to each other to form a ring. For example, the isopropyl groups of R ¹ and R ² are connected to form 4,4,5,5-tetramethyl-1,3,2- A dioxaborolane ring may be formed.

In general formula (II), R ¹ and R ² are preferably a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms, and R ¹ and R ² connected to form a ring, Most preferably, it is a hydrogen atom.

In general formula (II), R ³ represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group.
Examples of the aliphatic hydrocarbon group include substituted or unsubstituted linear or branched alkyl groups having 1 to 30 carbon atoms (for example, methyl group, ethyl group, iso-propyl group, n-propyl group, butyl group, pentyl group). Hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, Isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-methylhexyl group, etc.), substituted or unsubstituted cyclic alkyl group having 3 to 20 carbon atoms (for example, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group, etc.), alkenyl groups having 2 to 20 carbon atoms (for example, vinyl Bi, 1-propenyl, 1-butenyl, 1-methyl-1-propenyl group, etc.).
Examples of the aryl group include substituted or unsubstituted phenyl groups having 6 to 50 carbon atoms (for example, phenyl group, tolyl group, styryl group, 4-benzoyloxyphenyl group, 4-phenoxycarbonylphenyl group, 4-biphenyl group, 4 -(4-octyloxybenzoyloxy) phenoxycarbonylphenyl group and the like), substituted or unsubstituted naphthyl groups having 10 to 50 carbon atoms and the like (for example, unsubstituted naphthyl group and the like).
The heterocyclic group is, for example, a substituted or unsubstituted 5-membered or 6-membered ring group containing at least one heteroatom (for example, a nitrogen atom, an oxygen atom, a sulfur atom, etc.), such as pyrrole, furan, Thiophene, pyrazole, imidazole, triazole, oxazole, isoxazole, oxadiazole, thiazole, thiadiazole, indole, carbazole, benzofuran, dibenzofuran, thianaphthene, dibenzothiophene, indazolebenzimidazole, anthranyl, benzisoxazole, benzoxazole, benzothiazole, Purine, pyridine, pyridazine, pyrimidine, pyrazine, triazine, quinoline, acridine, isoquinoline, phthalazine, quinazoline, quinoxaline, naphthyridine, phenane Lorin, pteridine, morpholine, include groups such as piperidine.

Furthermore, one or more of these aliphatic hydrocarbon groups, aryl groups, and heterocyclic groups included in the heterocyclic group may be substituted with any substituent. Examples of the substituent include monovalent non-metallic atomic groups excluding hydrogen, halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups, alkoxy groups, aryloxy groups, mercapto groups, alkylthio groups. , Arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-aryl Amino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyl Oxy, alkylsulfoxy, arylsulfoxy, acylthio Group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N '-Diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido Group, N ′, N′-dialkyl-N-alkylureido group, N ′, N′-dialkyl-N-arylureido group, N′-aryl-N-alkylureido group, N′-aryl-N-arylureido Group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N′-alkyl-N′-aryl-N-alkyl Raid group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonyl Amino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group and its conjugate base group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl Group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkyl Sulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group Group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group, N-alkylsulfonylsulfur group Famoiru group _{(-SO 2 NHSO 2 (alkyl)} ) and its conjugated base group N- aryl acylsulfamoyl group _{(-SO 2 NHSO 2 (aryl)} ) and its conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ (alkyl)) and its conjugated base group, N- aryl sulfonyl carbamoyl group (—CONHSO ₂ (aryl)) and its conjugate base group, alkoxysilyl group (—Si (Oalkyl) ₃ ), aryloxysilyl group (—Si (Oaryl) ₃ ), hydroxysilyl group (—Si (OH) ₃ ) And its conjugate base group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (—PO ₃ (alkyl) ₂ ), diarylphosphono group (—PO ₃ (aryl) ₂ ), alkyl Arylphosphono group (—PO ₃ (alkyl) (aryl)), monoalkylphosphono group (—PO ₃ H (alkyl)) and its conjugate base group, monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group, phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group, dialkylphosphonooxy Group (—OPO ₃ (alkyl) ₂ ), diarylphosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylarylphosphonooxy group (—OPO ₃ (alkyl) (aryl)), monoalkylphosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group, monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base group, cyano group, nitro group, aryl group, alkenyl group, alkynyl group Is mentioned. Further, these substituents may combine with each other or with a substituted hydrocarbon group to form a ring, if possible.

R ³ in the general formula (II) is preferably a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, more preferably phenyl having a substituent containing at least one aryl group or heterocyclic group. More preferably, it is a phenyl group substituted at the 4-position by a substituent containing 2 to 4 phenyl groups.

Moreover, it is preferable that the boronic acid compound represented by the general formula (II) is substituted with a crosslinkable group, since the adhesion between the support and the optically anisotropic layer is improved. It is preferable that a crosslinkable group is contained in R ³ . The crosslinkable group is generally a polymerizable group, such as a vinyl group, an acrylate group, a methacrylate group, an acrylamide group, a styryl group, a vinyl ketone group, a butadiene group, a vinyl ether group, an oxiranyl group, an aziridinyl group, or an oxetane group. Examples thereof include a polymerizable group, preferably a vinyl group, an acrylate group, a methacrylate group, a styryl group, an oxiranyl group or an oxetane group, and most preferably a vinyl group, an acrylate group, an acrylamide group or a styryl group.

  Although the specific example of a compound represented by general formula (II) below is shown, the compound used for this invention is not limited to these.

  Boronic acid compounds are generally easily synthesized by using commercially available boronic acid compounds as they are, or by subjecting a boronic acid compound having a substituent as a raw material to general synthetic reactions such as esterification, amidation, and alkylation. I can do it. When a commercially available boronic acid compound is not used, for example, it is synthesized from a halide (for example, aryl bromide) by n-butyllithium and trialkoxyborane (for example, trimethoxyborane), or metal magnesium is used. It can be synthesized by performing a Wittig reaction.

  The preferable range of the content of the boronic acid compound in the optical compensation layer is 0.005 to 8% by mass in the optical compensation layer (in the total solid content excluding the solvent of the composition in the composition before layer formation). It is preferable that it is 0.01 to 5% by mass, and more preferably 0.05 to 1% by mass.

  In order to improve the adhesion between the polarizer and the optical compensation layer, the amount of the boronic acid compound is preferably set to the above lower limit value or more. On the other hand, the orientation of the discotic liquid crystalline compound can be improved by setting it to the upper limit value or less, and the front contrast can be prevented from lowering when incorporated in a liquid crystal display device.

<Polarizer>
A polarizer refers to a film that can be converted from natural light or polarized light into arbitrary polarized light. Any appropriate polarizer may be adopted as the polarizer used in the present invention, but a polarizer that converts natural light or polarized light into linearly polarized light is preferably used.

  In the polarizing plate used for this invention, arbitrary appropriate things can be employ | adopted as a polarizer according to the objective. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And a polyene-based oriented film such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product. Further, a guest / host type O-type polarizer in which a liquid crystalline composition containing a dichroic substance and a liquid crystalline compound disclosed in US Pat. No. 5,523,863 is aligned in a certain direction, US Pat. An E-type polarizer or the like in which lyotropic liquid crystals disclosed in US Pat. No. 6,049,428 are aligned in a certain direction can also be used.

Among such polarizers, from the viewpoint of having a high degree of polarization, a polarizer made of a polyvinyl alcohol film containing iodine is preferably used. Polyvinyl alcohol or a derivative thereof is used as a material for the polyvinyl alcohol film applied to the polarizer. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters and acrylamide. Things. Polyvinyl alcohol having a polymerization degree of about 1000 to 10000 and a saponification degree of about 80 to 100 mol% is generally used.

  The polyvinyl alcohol film may contain an additive such as a plasticizer. Examples of the plasticizer include polyols and condensates thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer used is not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol film.

  The polyvinyl alcohol film (unstretched film) is at least subjected to uniaxial stretching treatment and iodine dyeing treatment according to a conventional method. Furthermore, boric acid treatment and iodine ion treatment can be performed. Moreover, the polyvinyl alcohol film (stretched film) subjected to the treatment is dried according to a conventional method to form a polarizer.

  The stretching method in the uniaxial stretching treatment is not particularly limited, and either a wet stretching method or a dry stretching method can be employed. Examples of the stretching means of the dry stretching method include an inter-roll stretching method, a heated roll stretching method, and a compression stretching method. Stretching can also be performed in multiple stages. In the stretching means, the unstretched film is usually heated. Usually, an unstretched film having a thickness of about 30 to 150 μm is used. The stretch ratio of the stretched film can be appropriately set according to the purpose, but the stretch ratio (total stretch ratio) is about 2 to 8 times, preferably 3 to 6.5 times, more preferably 3.5 to 6 times. Is desirable. The thickness of the stretched film is preferably about 5 to 40 μm.

  The iodine staining treatment is performed by immersing the polyvinyl alcohol film in an iodine solution containing iodine and potassium iodide. The iodine solution is usually an iodine aqueous solution, and contains iodine and potassium iodide as a dissolution aid. The iodine concentration is about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight. The potassium iodide concentration is about 0.01 to 10% by weight, and further 0.02 to 8% by weight. It is preferable to use it.

  In the iodine dyeing treatment, the temperature of the iodine solution is usually about 20 to 50 ° C, preferably 25 to 40 ° C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds. In the iodine dyeing treatment, the iodine content and potassium content in the polyvinyl alcohol film are within the above ranges by adjusting the conditions such as the concentration of the iodine solution, the immersion temperature of the polyvinyl alcohol film in the iodine solution, and the immersion time. Adjust as follows. The iodine dyeing process may be performed at any stage before the uniaxial stretching process, during the uniaxial stretching process, or after the uniaxial stretching process.

  The boric acid treatment is performed by immersing a polyvinyl alcohol film in an aqueous boric acid solution. The boric acid concentration in the boric acid aqueous solution is about 2 to 15% by weight, preferably 3 to 10% by weight. The aqueous boric acid solution can contain potassium ions and iodine ions with potassium iodide. The potassium iodide concentration in the boric acid aqueous solution is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight. A boric acid aqueous solution containing potassium iodide can provide a lightly colored polarizer, that is, a so-called neutral gray polarizer having a substantially constant absorbance over almost the entire wavelength range of visible light.

  For the iodine ion treatment, for example, an aqueous solution containing iodine ions with potassium iodide or the like is used. The potassium iodide concentration is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight. In the iodine ion impregnation treatment, the temperature of the aqueous solution is usually about 15 to 60 ° C, preferably 25 to 40 ° C. The immersion time is usually about 1 to 120 seconds, preferably 3 to 90 seconds. The stage of iodine ion treatment is not particularly limited as long as it is before the drying process. It can also be performed after washing with water.

  The polarizer used in the present invention may be a coating type polarizer.

  The polarizer used in the present invention is preferably a thin polarizer from the viewpoint of thinning the liquid crystal display device. As the thin polarizer, representatively, JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 001460 specification, or Japanese Patent Application 2010- And a thin polarizer described in Japanese Patent Application No. 269002 and Japanese Patent Application No. 2010-263692. These thin polarizers can be obtained by a production method including a step of stretching and dyeing a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a stretching resin base material in a laminated state. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

<Polarizing plate protective film contained in viewing side polarizing plate>
There is no restriction | limiting in particular in the polarizing plate protective film contained in the visual recognition side polarizing plate used for this invention, The polarizing plate protective film used normally can be used. As an example, a polarizing plate protective film having a thickness of 20 to 30 μm described in JP-A No. 2001-187825 can be used.
Furthermore, according to the following description, a polarizing plate protective film included in the viewing side polarizing plate can be formed.

[Cellulose acylate film]
A cellulose acylate film containing cellulose acylate can be used for the polarizing plate protective film included on the viewer side used in the present invention. The cellulose acylate film that can be used in the present invention preferably has a cellulose acylate content of 70 to 95% by mass, more preferably 75 to 95% by mass, and 80 to 93% by mass. Is more preferable, and this makes it possible to produce a polarizing plate protective film excellent in polarizing plate processability.

  The cellulose acylate used in the cellulose acylate film that can be used in the present invention is an ester of a raw material cellulose and an acid, and is preferably a carboxylic acid ester having about 2 to 22 carbon atoms, and has 6 or less carbon atoms. The lower fatty acid ester is more preferable. In the cellulose acylate of the present invention, as a method for measuring the degree of substitution of acetic acid and / or a fatty acid having 3 to 22 carbon atoms to be substituted with a hydroxyl group of cellulose, a method according to ASTM D-817-91, or an NMR method Can be mentioned. In the case of cellulose acylate having about 2 to 22 carbon atoms, a condensate having a repeating unit is used, and in particular, in the case of cellulose acetate having 2 carbon atoms, in addition to this, an adduct having a repeating unit is used. Also preferably, the light unevenness of the liquid crystal display device can be improved.

  Cellulose acylate raw material cellulose used in the present invention includes 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. Detailed descriptions of these raw material celluloses can be found in, for example, Plastic Materials Course (17) Fibrous Resin (Maruzawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Open Technical Report 2001-1745 (page 7). To page 8), and the cellulose acylate film that can be used in the present invention is not particularly limited.

  In the cellulose acylate of the cellulose acylate film that can be used in the present invention, the degree of substitution of cellulose with a hydroxyl group is not particularly limited, but in order to impart appropriate moisture permeability and hygroscopicity to the film, The acyl substitution degree is preferably 2.00 to 3.00. Furthermore, the substitution degree is preferably 2.30 to 2.98, more preferably 2.70 to 2.96, and still more preferably 2.80 to 2.94.

  Of 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.

  Among these, acetyl groups, mixed esters of acetyl groups and propyl groups are preferred, and acetyl groups are particularly preferred from the viewpoints of ease of synthesis, cost, ease of control of substituent distribution, and the like.

  The degree of polymerization of cellulose acylate preferably used in the present invention is 180 to 700 in terms of viscosity average polymerization degree, and in cellulose acetate, 180 to 550 is more preferable, 180 to 400 is more preferable, and 180 to 350 is particularly preferable. . By setting the degree of polymerization to the above upper limit or less, the viscosity of the cellulose acylate dope solution tends to be an appropriate value, and film production tends to be facilitated by casting. There exists a tendency which can fully make the intensity | strength of the film produced by making a polymerization degree more than the said lower limit. 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. 18, No. 1, pages 105-120, 1962). This is described in detail in JP-A-9-95538.

  Further, the molecular weight distribution of cellulose acylate preferably 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, and molecular weight distribution. Is preferably narrow. The specific value of Mw / Mn is preferably 1.0 to 4.0, more preferably 2.0 to 3.5, and most preferably 2.3 to 3.4. 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 (narrow molecular weight distribution) can be synthesized. When used in the production of the cellulose acylate film of the present invention, the moisture content of the cellulose acylate is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.7%. It is below mass%. In general, cellulose acylate contains water, and its water content is known to be 2.5 to 5% by mass. In order to obtain the moisture content of the cellulose acylate as described above 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. Regarding these cellulose acylates of the present invention, the raw material cotton and the synthesis method thereof are disclosed on the 7th to 12th pages of the Japan Society for Invention and Innovation (public technical number 2001-1745, published on March 15, 2001, Japan Institute of Invention). It is described in detail.

  In the cellulose acylate film that can be used in the present invention, the cellulose acylate is used by mixing two or more different types of cellulose acylates from the viewpoint of substituents, substitution degree, polymerization degree, molecular weight distribution, and the like. Can do.

[Ultraviolet absorber]
The cellulose acylate film that can be used in the present invention may contain two or more kinds of ultraviolet absorbers. The two or more kinds of ultraviolet absorbers are preferably compounds not containing a halogen element, and are preferably compounds represented by the following general formula (III).

In general formula (III), X is a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, an amino group, or an amide group. If possible, these may further have a substituent.
In at least one of the ultraviolet absorbers, Y and Z in the general formula (III) are each independently an alkyl group, the alkyl group represented by Y and Z does not contain an aromatic ring as a substituent,
In at least one of the ultraviolet absorbers, Y and Z in the general formula (III) are each independently an alkyl group, and the alkyl group represented by Y and Z has one aromatic ring as a substituent.

  X is preferably a hydrogen atom, an alkyl group, an alkoxyl group, or a hydroxyl group.

  In general formula (III), X preferably represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, and more preferably a hydrogen atom.

  Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an isopropyl group, a tert-butyl group, an isobutyl group, and a sec-butyl group.

  Examples of the alkoxy group having 1 to 5 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, isopropoxy group, tert-butoxy group, isobutoxy group, sec-butoxy group and the like. .

In at least one of the ultraviolet absorbers, Y and Z in the general formula (III) are each independently an alkyl group, the alkyl group represented by Y and Z does not contain an aromatic ring as a substituent,
In at least one of the ultraviolet absorbers, Y and Z in the general formula (III) are each independently an alkyl group, and the alkyl group represented by Y and Z has one aromatic ring as a substituent.
Y and Z in general formula (III) are each independently an alkyl group, and the alkyl group represented by Y and Z does not contain an aromatic ring as a substituent, and Y and Z in general formula (III) are each In combination with an ultraviolet absorber that is independently an alkyl group and the alkyl group represented by Y and Z has one aromatic ring as a substituent, the effect of suppressing the whitening phenomenon during saponification is obtained. . As the aromatic ring, a benzene ring is preferable.

  Y and Z each preferably represent a substituted or unsubstituted alkyl group having 2 to 20 carbon atoms.

  The substituted or unsubstituted alkyl group having 2 to 20 carbon atoms may be linear or branched, and may have a substituent. Examples of the substituted or unsubstituted alkyl group having 2 to 20 carbon atoms include an ethyl group, an isopropyl group, a tert-butyl group, a tert-amyl group, a tert-octyl group, a hydroxyethyl group, a methoxymethyl group, and a butoxyethyl group. Is mentioned.

  Y and Z in general formula (III) are each independently an alkyl group, and the alkyl group represented by Y and Z does not contain an aromatic ring as a substituent, and Y and Z in general formula (III) are each The content ratio with the ultraviolet absorber which is independently an alkyl group and the alkyl group represented by Y and Z has one aromatic ring as a substituent is preferably 95: 5 to 10:90, and 80:20 to 50: 50 is more preferable.

  From the viewpoint of spectral transmittance, the total addition amount of the ultraviolet absorber is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the cellulose acylate. preferable.

[Plasticizer]
The cellulose acylate film that can be used in the present invention preferably contains at least one plasticizer. The plasticizer suppresses the aggregation of polymer chains and contributes to improving properties from the viewpoint of haze and brittleness.
From the viewpoint of film viscoelasticity, the content of the plasticizer is preferably 5 parts by mass or more and 25 parts by mass or less, and more preferably 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of cellulose acylate.

  As the plasticizer, various plasticizers conventionally used for cellulose acylate films can be used. Among these, a mixture of triphenyl phosphate and biphenyl diphenyl phosphate is preferable.

[High molecular weight plasticizer]
The cellulose acylate film that can be used in the present invention may use a high molecular weight plasticizer as a plasticizer.
The high molecular weight plasticizer used in the present invention has a molecular weight of 700 to 10,000 and has a repeating unit. Here, the molecular weight of the high molecular weight plasticizer is an average molecular weight and is composed of a mixture having different molecular weights. In solution casting, a plasticizer is an essential material for increasing the volatilization rate of a solvent and reducing the amount of residual solvent. Also in a polymer film obtained by a melt film forming method, a plasticizer is a useful material for preventing coloration and film strength deterioration. Furthermore, the addition of the high molecular weight plasticizer to the cellulose acylate film that can be used in the present invention is a viewpoint of film modification such as improvement of mechanical properties, imparting flexibility, imparting water absorption resistance, and reducing moisture permeability. It shows a useful effect. Further, the present invention is very effective for improving the handling characteristics in the manufacturing process.

  Here, the high molecular weight plasticizer that can be used in the present invention may be a compound having a repeating unit portion in the compound. The polymer plasticizer preferably has a number average molecular weight of 600 to 10000, more preferably a number average molecular weight of 600 to 8000, still more preferably a number average molecular weight of 700 to 5000, and a number average molecular weight. It is especially preferable that it is 700-3500.

  The high molecular weight plasticizer that can be used in the present invention may be liquid or solid at the ambient temperature or humidity used. The melting point is classified by the film forming method. In the case of solution casting, the melting point is preferably −100 ° C. to 150 ° C., more preferably −100 ° C. to 70 ° C., and particularly preferably the melting point − It is preferable that it is 100 to 50 degreeC. On the other hand, in the case of melt film formation, the melting point is preferably −100 ° C. to 200 ° C., more preferably the melting point is −100 ° C. to 170 ° C., and particularly preferably the melting point is −100 ° C. to 150 ° C. is there.

Further, the smaller the color, the better, and it is particularly preferable that the color is colorless. Thermally, it is preferably stable at a higher temperature, and the decomposition start temperature is preferably 150 ° C. or higher, more preferably 200 ° C. or higher. The addition amount may be as long as it does not adversely affect the optical properties and mechanical properties, and the blending amount thereof is appropriately selected within the range not impairing the object of the present invention, and the high molecular weight plasticizer in the cellulose acylate film that can be used in the present invention. The content is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, based on the cellulose acylate. 5-30 mass% is especially preferable.
Hereinafter, the high molecular weight plasticizer used in the present invention will be described in detail with specific examples.

  As the high molecular weight plasticizer that can be used in the present invention, in the high molecular weight plasticizer having a repeating unit composed of a dicarboxylic acid and a diol, the dicarboxylic acid forming the high molecular weight plasticizer is at least one kind of carbon number 2-20. An alkylene dicarboxylic acid and at least one aromatic dicarboxylic acid having 8 to 20 carbon atoms, and the diol is an alkylene diol having 2 to 20 carbon atoms, an alkyl ether diol having 4 to 20 carbon atoms, and 6 to 20 carbon atoms. A high molecular weight plasticizer comprising at least one diol selected from the following aromatic ring-containing diols (also referred to as aromatic diols).

The high molecular weight plasticizer that can be used in the present invention will be described below.
The high molecular weight plasticizer that can be used in the present invention includes a mixture of an aliphatic dicarboxylic acid having 2 to 20 carbon atoms and an aromatic dicarboxylic acid having 8 to 20 carbon atoms, an aliphatic diol having 2 to 12 carbon atoms, and a carbon number. It is obtained by a reaction with at least one kind of diol selected from 4 to 20 alkyl ether diols and 6 to 20 aromatic diols, and both ends of the reactants may remain as reactants. Further, the so-called terminal sealing may be carried out by further reacting monocarboxylic acids, monoalcohols or phenols. It is effective in terms of storage stability that the end capping is performed in particular so as not to contain free carboxylic acids. The dicarboxylic acid used in the high molecular weight plasticizer of the present invention is preferably an aliphatic dicarboxylic acid residue having 4 to 20 carbon atoms or an aromatic dicarboxylic acid residue having 8 to 20 carbon atoms.

Examples of the aliphatic dicarboxylic acid having 2 to 20 carbon atoms preferably used in the present invention include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid. , Sebacic acid, dodecanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid.
Examples of the aromatic dicarboxylic acid having 8 to 20 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8 -Naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid.

  Among these, preferable aliphatic dicarboxylic acids are malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, and 1,4-cyclohexanedicarboxylic acid, and aromatic dicarboxylic acid is phthalic acid. Acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid. Particularly preferably, the aliphatic dicarboxylic acid component is succinic acid, glutaric acid, and adipic acid, and the aromatic dicarboxylic acid is phthalic acid, terephthalic acid, and isophthalic acid.

  In the present invention, at least one of the above-mentioned aliphatic dicarboxylic acids and aromatic dicarboxylic acids can be used in combination, but the combination is not particularly limited, and there is a problem even if several types of each component are combined. Absent.

  Next, the diol or aromatic ring-containing diol used for the high molecular weight plasticizer will be described. It is selected from aliphatic diols having 2 to 20 carbon atoms, alkyl ether diols having 4 to 20 carbon atoms, and aromatic ring-containing diols having 6 to 20 carbon atoms.

  First, examples of the aliphatic diol having 2 to 20 carbon atoms include alkyl diols and alicyclic diols, such as ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl) Glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethane 1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Used as a seed or a mixture of two or more.

  Preferred aliphatic diols include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1 , 4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, particularly preferred Is ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol.

  Preferred examples of the alkyl ether diol having 4 to 20 carbon atoms include polytetramethylene ether glycol, polyethylene ether glycol and polypropylene ether glycol, and combinations thereof. Although the average degree of polymerization is not particularly limited, it is preferably 2 to 20, more preferably 2 to 10, further 2 to 5, and particularly preferably 2 to 4. For these examples, typically useful polyether glycols include Carbowax, Pluronics and Niax resins.

  Examples of the aromatic diol having 6 to 20 carbon atoms include, but are not limited to, bisphenol A, 1,2-hydroxybenzene, 1,3-hydroxybenzene, 1,4-hydroxybenzene, and 1,4-benzenedimethanol. Of these, bisphenol A, 1,4-hydroxybenzene, and 1,4-benzenedimethanol are preferred.

  The high molecular weight plasticizer that can be used in the present invention is particularly preferably a high molecular weight plasticizer whose terminal is sealed with an alkyl group or an aromatic group. This is because the terminal is protected with a hydrophobic functional group, which is effective against deterioration with time at high temperature and high humidity, and is due to the role of delaying hydrolysis of the ester group.

The high molecular weight plasticizer that can be used in the present invention is preferably protected with a monoalcohol residue or a monocarboxylic acid residue so that both ends do not become carboxylic acid or OH group.
In this case, the monoalcohol residue is preferably a substituted or unsubstituted monoalcohol residue having 1 to 30 carbon atoms, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, hexanol, isopropanol. Hexanol, cyclohexyl alcohol, octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, dodecaoctanol, allyl alcohol, oleyl alcohol and other aliphatic alcohols, benzyl alcohol And substituted alcohols such as 3-phenylpropanol.

  The end-capping alcohol residues that can be preferably used are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol, isooctanol, 2-ethylhexyl alcohol, isononyl alcohol, Oleyl alcohol and benzyl alcohol, especially methanol, ethanol, propanol, isobutanol, cyclohexyl alcohol, 2-ethylhexyl alcohol, isononyl alcohol and benzyl alcohol.

  Moreover, when sealing with a monocarboxylic acid residue, the monocarboxylic acid used as a monocarboxylic acid residue is preferably a substituted or unsubstituted monocarboxylic acid having 1 to 30 carbon atoms. These may be aliphatic monocarboxylic acids or aromatic ring-containing carboxylic acids. First, preferable aliphatic monocarboxylic acids are described. Examples include acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, and oleic acid. As the aromatic ring-containing monocarboxylic acid, For example, benzoic acid, p-tert-butylbenzoic acid, p-tert-amylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, etc. Each of these can be used alone or in combination of two or more.

  The high molecular weight plasticizer that can be used in the present invention is synthesized by heat melting by a polyesterification reaction or transesterification reaction of the above dicarboxylic acid with a diol and / or a monocarboxylic acid or monoalcohol for end-capping by a conventional method. It can be easily synthesized by either a condensation method or an interfacial condensation method of acid chlorides of these acids and glycols. These polyester plasticizers are described in detail in Koichi Murai, “Plasticizers, Theory and Applications” (Koshobo Co., Ltd., first edition published on March 1, 1973). In addition, Japanese Patent Laid-Open Nos. 05-155809, 05-155810, Japanese Patent Laid-Open Nos. 05-97073, 2006-259494, 07-330670, 2006-342227, 2007-003679. The materials described in each publication can also be used.

[Sugar ester compounds]
The cellulose acylate film that can be used in the present invention may contain a sugar ester compound as a plasticizer.
By adding the sugar ester compound to the cellulose acylate film, it is possible to reduce the total haze and internal haze without deteriorating the expression of optical properties and without performing heat treatment before the stretching step. Furthermore, the front contrast can be greatly improved by using the cellulose acylate film of the present invention in a liquid crystal display device.

{Sugar residue}
The sugar ester compound is a compound in which at least one substitutable group (for example, hydroxyl group, carboxyl group) in the monosaccharide or polysaccharide constituting the compound and at least one substituent group are ester-bonded. Say that. That is, the sugar ester compound referred to here includes a wide range of sugar derivatives, for example, a compound containing a sugar residue such as gluconic acid as a structure. That is, the sugar ester compound includes an ester of glucose and carboxylic acid and an ester of gluconic acid and alcohol.
The substitutable group in the monosaccharide or polysaccharide constituting the sugar ester compound is preferably a hydroxyl group.

  The sugar ester compound includes a structure derived from a monosaccharide or a polysaccharide constituting the sugar ester compound (hereinafter also referred to as a sugar residue). The structure of the sugar residue per monosaccharide is referred to as the structural unit of the sugar ester compound. The structural unit of the sugar ester compound preferably includes a pyranose structural unit or a furanose structural unit, and more preferably all sugar residues are a pyranose structural unit or a furanose structural unit. Further, when the sugar ester is composed of a polysaccharide, it preferably contains both a pyranose structural unit or a furanose structural unit.

  The sugar residue of the sugar ester compound may be derived from 5 monosaccharides or 6 monosaccharides, but is preferably derived from 6 monosaccharides.

  The number of structural units contained in the sugar ester compound is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 or 2.

  The sugar ester compound that can be used in the present invention is more preferably a sugar ester compound containing 1 to 12 pyranose structural units or furanose structural units in which at least one hydroxyl group is esterified. More preferably, it is a sugar ester compound containing one or two pyranose structural units or furanose structural units, one of which is esterified.

  Examples of the monosaccharide or saccharide containing 2 to 12 monosaccharide units include, for example, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, fructose, mannose, gulose, idose, galactose , Talose, trehalose, isotrehalose, neotrehalose, trehalosamine, caudibiose, nigerose, maltose, maltitol, isomaltose, sophorose, laminaribiose, cellobiose, gentiobiose, lactose, lactosamine, lactitol, lactulose, melibiose, primebelloose, rutiose , Sucrose, sucralose, turanose, vicyanose, cellotriose, cacotriose, gentianose, isomaltoto Ose, isopanose, maltotriose, manninotriose, melezitoose, panose, planteose, raffinose, solatriose, umbelliferose, lycotetraose, maltotetraose, stachyose, baltopentaose, velval course, maltohexaose, Examples include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin, xylitol, sorbitol and the like.

  Preferably, ribose, arabinose, xylose, lyxose, glucose, fructose, mannose, galactose, trehalose, maltose, cellobiose, lactose, sucrose, sucralose, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin Xylitol, sorbitol, more preferably arabinose, xylose, glucose, fructose, mannose, galactose, maltose, cellobiose, sucrose, β-cyclodextrin, γ-cyclodextrin, particularly preferably xylose, glucose, fructose , Mannose, galactose, maltose, cellobiose, sucrose, xylitol, sorbitol.

{Substituent structure}
It is more preferable that the sugar ester compound that can be used in the present invention has a structure represented by the following general formula (1A) including the substituent to be used.
Formula _{(1A) (OH) p -G-} (L 1 -R 11) q (O-R 12) r
In General Formula (1A), G represents a sugar residue, L ¹ represents any ^one of —O—, —CO—, and —NR ¹³ —, and R ¹¹ represents a hydrogen atom or a monovalent substituent. R ¹² represents a monovalent substituent bonded by an ester bond. p, q, and r each independently represent an integer of 0 or more, and p + q + r is equal to the number of hydroxyl groups on the assumption that G is an unsubstituted saccharide having a cyclic acetal structure.

  The preferable range of G is the same as the preferable range of the sugar residue.

L ¹ is preferably —O— or —CO—, and more preferably —O—. When L ¹ is —O—, it is particularly preferably a linking group derived from an ether bond or an ester bond, and more preferably a linking group derived from an ester bond.
Further, when there are a plurality of L ^{1 s} , they may be the same or different.

At least one of R ¹¹ and R ¹² preferably has an aromatic ring.

In particular, when L ¹ is —O— (that is, when R ¹¹ and R ¹² are substituted on the hydroxyl group in the sugar ester compound), R ¹¹ , R ¹² and R ¹³ are substituted or unsubstituted. Are preferably selected from the group consisting of acyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted amino groups, substituted or unsubstituted acyl groups, substituted or unsubstituted A substituted alkyl group or a substituted or unsubstituted aryl group is more preferable, and an unsubstituted acyl group, a substituted or unsubstituted alkyl group, or an unsubstituted aryl group is particularly preferable.
When there are a plurality of R ¹¹ , R ¹² and R ¹³ , they may be the same as or different from each other.

Said p represents an integer greater than or equal to 0, and its preferable range is the same as the preferable range of the number of hydroxyl groups per monosaccharide unit mentioned later.
The r preferably represents a number larger than the number of pyranose structural units or furanose structural units contained in the G.
Q is preferably 0.
Moreover, since p + q + r is equal to the number of hydroxyl groups assuming that G is an unsubstituted saccharide having a cyclic acetal structure, the upper limit values of p, q and r are uniquely determined according to the structure of G. Is done.

  Preferred examples of the substituent of the sugar ester compound include an alkyl group (preferably an alkyl group having 1 to 22 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably an alkyl group having 1 to 8 carbon atoms, such as a methyl group, An ethyl group, a propyl group, a hydroxyethyl group, a hydroxypropyl group, a 2-cyanoethyl group, a benzyl group, etc.), an aryl group (preferably having a carbon number of 6 to 24, more preferably 6 to 18 and particularly preferably 6 to 12). A group such as a phenyl group or a naphthyl group, an acyl group (preferably having a carbon number of 1 to 22, more preferably a carbon number of 2 to 12, particularly preferably a carbon number of 2 to 8, such as an acetyl group or a propionyl group, Butyryl group, pentanoyl group, hexanoyl group, octanoyl group, benzoyl group, toluyl group, phthalyl group), amide group (preferred) Or an amide group (preferably 4 to 22 carbon atoms, more preferably an amide having 2 to 12 carbon atoms, particularly preferably an amide having 2 to 8 carbon atoms, such as a formamide group or an acetamide group). May include amide groups having 4 to 12 carbon atoms, particularly preferably 4 to 8 carbon atoms (for example, succinimide group, phthalimide group, etc.). Among them, an alkyl group or an acyl group is more preferable, a methyl group, an acetyl group, or a benzoyl group is more preferable, and among them, a benzoyl group is particularly preferable.

  The number of hydroxyl groups per structural unit in the sugar ester compound (hereinafter also referred to as hydroxyl group content) is preferably 3 or less, and more preferably 1 or less. By controlling the hydroxyl group content within the above range, the migration of sugar ester compounds to the polarizer and the destruction of the PVA-iodine complex during high temperature and high humidity can be suppressed, and the deterioration of the polarizer performance during high temperature and high humidity can be suppressed. This is preferable.

  As the method for obtaining the sugar ester compound, commercially available products such as those manufactured by Tokyo Chemical Industry Co., Ltd., Aldrich, etc., or known ester derivatization methods for commercially available carbohydrates (for example, Japanese Patent Laid-Open No. Hei. Can be synthesized by carrying out the method described in JP-A-8-245678.

  The sugar ester compound has a number average molecular weight of preferably 200 to 3500, more preferably 200 to 3000, and particularly preferably 250 to 2000.

  Specific examples of the sugar ester compound that can be preferably used in the present invention are listed below, but the present invention is not limited to the following embodiments.

Sugar ester (1):

Sugar ester (2): Ac represents an acetyl group.

Sugar ester (3):

Sugar ester (4): Bz represents a benzoyl group.

  In the following structural formulae, R each independently represents an arbitrary substituent, and a plurality of R may be the same or different. The ClogP value is a value obtained by calculating the common logarithm logP of the distribution coefficient P between 1-octanol and water. For calculation of ClogP value, the CLOGP program incorporated in the system: PCModels of Daylight Chemical Information Systems was used.

The sugar ester compound is preferably contained in an amount of 2 to 30 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of cellulose acylate.
Moreover, when using together a polyester plasticizer with a sugar ester compound, the addition amount (mass part) of the sugar ester compound with respect to the addition amount (mass part) of a polyester plasticizer should add 2-10 times (mass ratio). It is more preferable to add 3 to 8 times (mass ratio).

[Matting agent fine particles]
It is preferable to add fine particles as a matting agent to the cellulose acylate film that can be used in the present invention. The fine particles that can be used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate. And calcium phosphate. Fine particles containing silicon are preferable from the viewpoint of reducing 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 to 1.5 μm, more preferably from 0.4 to 1.2 μm, and most preferably from 0.6 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.

  Commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.) can be used as the silicon dioxide fine particles. 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, while keeping the turbidity of the cellulose acylate film low. This is particularly preferable because the effect of reducing the friction coefficient is great.

  In order to obtain a cellulose acylate film having particles having a small secondary average particle size in the present invention, several methods are conceivable when preparing a fine particle dispersion. For example, there is a method in which a fine particle dispersion prepared by stirring and mixing a solvent and fine particles is prepared in advance, and this fine particle dispersion is added to a small amount of a separately prepared solution, dissolved by stirring, and further mixed with the main dope solution. 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 acylate 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 in the final dope solution is preferably as long as the haze of the film allows, preferably 0.01 to 1.0 g per 1 m ² , more preferably 0.03 to 0.3 g, 0.08 to 0.16 g is most preferable. Further, when the cellulose acylate film is formed from multiple layers by a film forming method such as co-casting, it is preferable not to add to the inner layer, but to add only to the surface layer side. The addition amount of the agent is preferably 0.001% by mass or more and 0.2% by mass or less, and more preferably 0.01% by mass or more and 0.1% by mass or less.

  As the solvent used for dispersion, lower alcohols are preferable, and examples thereof include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, and butyl alcohol. 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 formation of a cellulose acylate.

[Other additives]
Various additives (for example, a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a release agent, an infrared absorber, a wavelength dispersion adjusting agent, etc.) can be added to the cellulose acylate film that can be used in the present invention. , They 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, infrared absorbing dyes are described in, for example, JP-A No. 2001-194522. Moreover, the addition time may be added at any time in the dope preparation step, but may be added by adding an additive to the final preparation step of the dope preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, and 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 Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

{Addition amount of additive}
In the cellulose acylate film that can be used in the present invention, when these other additives are added, the total amount of the additives is preferably 5 to 50% by mass with respect to the cellulose acylate, and 5 to 40%. It is more preferable that it is mass%, and it is still more preferable that it is 5-30 mass%.

{Film forming process}
As a process for forming a cellulose acylate film that can be used in the present invention, a method of forming a known cellulose acylate film can be widely adopted, and it is preferable to form a film by a solvent casting method. In the solvent cast method, a film can be formed using a solution (dope) in which cellulose acylate is dissolved in an organic solvent.
The organic solvent is a solvent selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. It is preferable to contain. The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

Examples of the ether having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole.
Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone.
Examples of the esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.
Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.
The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of halogen atoms substituted by halogen in the halogenated hydrocarbon is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is most preferable that it is 40-60 mol%. Methylene chloride is a representative halogenated hydrocarbon. Two or more organic solvents may be mixed and used.

A cellulose acylate solution can be prepared by a general method. A general method means processing at a temperature of 0 ° C. or higher (ordinary temperature or high temperature). The solution can be prepared by using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly, methylene chloride) as the organic solvent.
The amount of cellulose acylate is adjusted so as to be contained in the obtained solution in an amount of 10 to 40% by mass. The amount of cellulose acylate is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent).
The solution can be prepared by stirring the cellulose acylate and the organic solvent at room temperature (0 to 40 ° C.). The high concentration solution may be stirred under pressure and heating conditions. Specifically, the cellulose acylate and the organic solvent are placed in a pressure vessel and sealed, and stirred while being heated to a temperature equal to or higher than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., and more preferably 80 to 110 ° C.

Each component may be coarsely mixed in advance and then placed in a container. Moreover, you may put into a container sequentially. The container needs to be configured so that it can be stirred. The container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. The entire container can also be heated by providing a plate heater outside the container and piping to circulate the liquid.
It is preferable to provide a stirring blade inside the container and stir using this. The stirring blade preferably has a length that reaches the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in a container. The prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.

From the prepared cellulose acylate solution (dope), a cellulose acylate film can be produced by a solvent cast method.
The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 18 to 35% by mass. The surface of the drum or band is preferably finished in a mirror state. For casting and drying methods in the solvent casting method, U.S. Pat. No. 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, No. 60-203430, and No. 62-1115035.

  The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band and further dried with high-temperature air whose temperature is successively changed from 100 ° C to 160 ° C to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping.

[Thickness of polarizing plate protective film]
The thickness of the polarizing plate protective film used in the present invention is preferably 15 μm to 40 μm, more preferably 20 μm to 35 μm, from the viewpoint of making a thin polarizing plate.

[Haze of polarizing plate protective film]
The haze of the polarizing plate protective film used in the present invention is preferably as small as possible, and is preferably 0.01 to 2.0%. More preferably, it is 1.0% or less, More preferably, it is 0.5% or less. However, even if the haze value is higher than these preferred ranges, the haze of the polarizing plate protective film used in the present invention is dominated by the surface haze component resulting from the surface shape. When the surface shape is changed by adhering to a polarizer or applying an adhesive, it disappears and there is no effect on the display characteristics of the liquid crystal display device. However, haismura that is visually recognized between a portion where pressure is applied and a portion where pressure is not is problematic in terms of film appearance. For this reason, the haze distribution evaluated as the haze distribution of the polarizing plate protective film used in the present invention is preferably 0.5% or less, more preferably 0.3% or less, and 0.1% or less. More preferably, it is most preferably 0.05% or less. The haze can be measured according to JIS K-6714 by using a haze meter (HGM-2DP, Suga Tester), etc., at 25 ° C. and 60% RH for the optical film sample 40 mm × 80 mm of the present invention.

<Surface layer>
The viewing side polarizing plate used in the present invention preferably has an antireflection layer on the further viewing side of the polarizing plate protective film. As the antireflection layer, an antiglare layer or a low reflection layer in which various layers having different refractive indexes are laminated may be used, and these may be combined.

[Anti-glare layer]
The antiglare layer in the antireflection layer is formed for the purpose of imparting to the film an antiglare property due to surface scattering and preferably a hard coat property for improving the hardness and scratch resistance of the film.

  The antiglare layer that can be used in the present invention contains a binder and translucent particles for imparting antiglare properties, and has a surface formed by projections of the translucent particles themselves or projections formed of an aggregate of a plurality of particles. It is preferable that the unevenness is formed.

Specific examples of the translucent particles include particles of inorganic compounds such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles; Are preferred. Of these, crosslinked styrene particles, crosslinked acrylic particles, and silica particles are preferred.
The shape of the light-transmitting particles can be either spherical or irregular.

  From the viewpoint of adjusting internal haze and surface haze, the refractive index of the binder is preferably adjusted in accordance with the refractive index of each light-transmitting particle selected from the above-mentioned particles. As a binder according to the translucent particles, for example, a binder (having a refractive index after curing of 1.55 to 1.70) mainly composed of a trifunctional or higher functional (meth) acrylate monomer, and a styrene content of 50 to 50 Examples thereof include a combination of one or both of translucent particles and benzoguanamine particles composed of a crosslinked poly (meth) acrylate polymer that is 100% by mass, and among these, the binder and styrene content of 50 to 100% by mass The combination with the translucent particle | grains (refractive index of 1.54-1.59) which consists of a crosslinked poly (styrene-acrylate) copolymer which is is suitably illustrated.

Moreover, from the viewpoint mentioned above, the absolute value of the difference between the refractive index of the binder and the refractive index of the translucent particles is preferably 0.04 or less. The absolute value of the difference between the refractive index of the binder and the refractive index of the translucent particles is preferably 0.001 to 0.030, more preferably 0.001 to 0.020, and still more preferably 0.001 to 0.00. 015.
Here, the refractive index of the binder can be quantitatively evaluated by directly measuring it with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry. The refractive index of the translucent particles is determined by measuring the turbidity by dispersing the same amount of the translucent particles in the solvent in which the refractive index is changed by changing the mixing ratio of two kinds of solvents having different refractive indexes. It is measured by measuring the refractive index of the solvent when the degree becomes minimum with an Abbe refractometer.

  The content of the translucent particles is preferably 3 to 30% by mass, and 5 to 20% by mass with respect to the total solid content in the formed antiglare layer, from the viewpoint of antiglare properties and the like. Is more preferable.

  Moreover, you may use together and use 2 or more types of translucent particle | grains from which a particle diameter differs. It is possible to impart an antiglare property with a light-transmitting particle having a larger particle size and to impart another optical characteristic with a light-transmitting particle having a smaller particle size.

  In the present invention, in order to control the cohesiveness of the light-transmitting particles, an embodiment using a smectite-type clay organic composite obtained by intercalating a quaternary ammonium salt to the smectite-type clay is also preferable. Illustrated. The content of the smectite-type clay organic complex is preferably 0.2 to 8.0% by mass, more preferably 0.3 to 4.0% by mass, based on the total solid content of the formed antiglare layer. 0.4-3.0 mass% is further more preferable, and 0.5-2.0 mass% is especially preferable.

As the quaternary ammonium salt, a quaternary ammonium salt represented by the following general formula (IV) is preferable.
[(R ¹ ) ₃ (R ² ) N] + · X ⁻ (IV)
(In the formula, R ¹ and R ² are not the same, R ¹ represents an alkyl group, an alkenyl group or an alkynyl group having 4 to 24 carbon atoms, and R ² represents an alkyl group or an alkenyl group having 1 to 10 carbon atoms. Or an alkynyl group, and X ⁻ represents an anion.)

  As the ammonium ion of the general formula (IV), for example, trioctyl methyl ammonium ion, tristearyl ethyl ammonium ion, trioctyl ethyl ammonium ion, tristearyl methyl ammonium ion, tridecyl hexyl ammonium ion, Examples thereof include tritetradecyl propyl ammonium ion, among which trioctyl methyl ammonium ion and tristearyl ethyl ammonium ion are preferably exemplified.

In the general formula (IV), X ⁻ represents an anion. Examples of such anions include Cl ⁻ , Br ⁻ , OH ⁻ , NO ₃ ^{− and the} like, and Cl ⁻ is preferably exemplified.

  Examples of commercially available smectite-type clay organic composites include Lucentite SAN, Lucentite STN, Lucentite SEN, and Lucentite SPN (manufactured by Coop Chemical Co., Ltd.). These can be used alone or in combination of two or more. it can.

  The film thickness of the antiglare layer that can be used in the present invention is preferably 0.5 μm to 50 μm, more preferably 1 to 35 μm, and still more preferably 1 μm to 25 μm.

The center line average roughness (Ra ₇₅ ) of the antiglare layer that can be used in the present invention is preferably in the range of 0.10 to 0.40 μm.
The strength of the antiglare layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test.

  Examples of the method for forming the antiglare layer include a method of laminating and forming a mat-shaped shaping film having fine irregularities on the surface as described in claim 22 of JP-A-6-16851, A method of forming by curing shrinkage of an ionizing radiation curable resin due to a difference in ionizing radiation dose as described in claim 10 of Kai 2000-206317, and claim 6 of JP 2000-338310 A A method of forming irregularities on the surface of a coating film by solidifying the light-transmitting fine particles and the light-transmitting resin by gelation by reducing the weight ratio of the good solvent to the light-transmitting resin upon drying, As described in claim 8 of -275404, a method of imparting surface irregularities by external pressure is known, and these known methods can be used.

  Moreover, the aspect which made the polarizing plate protective film contain translucent particle | grains and provided the anti-glare function to the support body can also be used preferably. As such an embodiment, a film having an antiglare function described in claim 1 of JP-A-2009-258720 and claim 1 of JP-A-2005-105926 is preferably exemplified.

[High refractive index layer, medium refractive index layer, and low refractive index layer]
The refractive index of the high refractive index layer is preferably 1.70 to 1.74, more preferably 1.71 to 1.73. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the medium refractive index layer is preferably 1.60 to 1.64, and more preferably 1.61 to 1.63. The low refractive index layer preferably has a refractive index of 1.30 to 1.47. In the case of a multilayer thin film interference type antireflection film (medium refractive index layer / high refractive index layer / low refractive index layer), the refractive index of the low refractive index layer is preferably 1.33-1.38. More preferably, it is 35-1.37.
The high refractive index layer, medium refractive index layer, and low refractive index layer are formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, particularly a vacuum vapor deposition method or a sputtering method, which is a kind of physical vapor deposition method, and an inorganic substance. Although a transparent oxide thin film can be used, a method using all wet coating is preferred.
As the high refractive index layer, the medium refractive index layer, and the low refractive index layer, those described in paragraphs [0197] to [0211] of JP-A-2009-98658 can be used.

<Hard coat layer>
In the protective film for polarizing plate used in the present invention, a hard coat layer may be provided in order to impart physical strength of the film. Although it is not necessary to provide a hard coat layer, it is preferable to provide a hard coat layer because the scratch-resistant surface such as a pencil scratch test becomes stronger.
As the hard coat layer, those described in paragraphs [0190] to [0196] of JP-A-2009-98658 can be used.

(Backlight side polarizing plate)
The backlight side polarizing plate used in the VA mode liquid crystal display device of the present invention has an optical compensation layer, a polarizer, and a polarizing plate protective film in this order from the liquid crystal cell side.

<Optical compensation layer included in backlight-side polarizing plate>
The optical compensation layer included in the backlight side polarizing plate used in the present invention has a thickness of 10 μm to 60 μm. More preferably, it is 12-55 micrometers, More preferably, it is 15-50 micrometers.

The optical compensation layer is
30 nm ≦ Re (550) ≦ 200 nm, 50 nm ≦ Rth (550) ≦ 400 nm
Meet. More preferably, 40 nm ≦ Re (550) ≦ 180 nm, 60 nm ≦ Rth (550) ≦ 350 nm
More preferably, 50 nm ≦ Re (550) ≦ 170 nm, 70 nm ≦ Rth (550) ≦ 300 nm
It is preferable that
Here, Re (550) and Rth (550) represent in-plane retardation at a wavelength of 550 nm and retardation in the thickness direction.

The optical compensation layer preferably satisfies 5 ≦ Re (450) / Re (550) <1.0. Here, Re (450) and Re (550) represent in-plane retardation at wavelengths of 450 nm and 550 nm, respectively, and the above relationship indicates that the in-plane retardation is reversely dispersible.
It is preferable that the retardation of the optical compensation layer contained in the backlight-side polarizing plate is reversely dispersive, because when viewed in a liquid crystal display device, the viewing angle at the time of black display becomes good.

  The optical compensation layer included in the backlight side polarizing plate is preferably a polymer film. As the optical compensation layer, it is conceivable to use a rod-like liquid crystalline compound or the like. However, by using a polymer film, the front contrast when incorporated in a VA mode liquid crystal display device is improved as compared with the case of using a rod-like liquid crystalline compound. It turns out that it can improve.

  The polymer film material is preferably a polymer excellent in optical performance, transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., but any material is acceptable as long as it satisfies the above conditions. May be used. Examples include polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, and styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin). Polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers , Polyether ether ketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, or polymers mixed with the above polymers Take as an example.

  As a material for forming the polymer film, a thermoplastic norbornene resin can be preferably used. Examples of the thermoplastic norbornene-based resin include ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., and ARTON manufactured by JSR Corporation.

  Moreover, as a material which forms the said polymer film, the cellulose acylate which can be used for the polarizing plate protective film contained in the visual recognition side polarizing plate mentioned above can also be used.

[Cellulose acylate film]
Hereinafter, the preferable aspect at the time of using a cellulose acylate film as an optical compensation layer contained in a backlight side polarizing plate is demonstrated.

  The cellulose acylate that can be used in the present invention preferably contains, as a main component, cellulose acylate having an average acyl group substitution degree DS satisfying 2.0 <DS <2.95. The average acyl substitution degree DS is more preferably 2.0 <DS <2.93, and more preferably 2.1 <DS <2.91.

Here, “as the main component” indicates a polymer when it is composed of a single polymer, and when it is composed of a plurality of polymers, the polymer having the highest mass fraction among the constituent polymers. It shows that.
In the cellulose acylate, the degree of substitution of cellulose with a hydroxyl group is not particularly limited. Can be obtained. As a measuring method, it can implement according to ASTMD-817-91.

[Manufacture of cellulose acylate film]
The method for producing a cellulose acylate film that can be used in the present invention includes a film forming step of casting a dope on a support and evaporating the solvent to form a cellulose acylate film, and then a stretching step of stretching the film. Further, it is preferable to further include a drying step of drying the obtained film, and a step of heat-treating at a temperature of 150 to 200 ° C. for 1 minute or more after the drying step.

{Co-casting}
The cellulose acylate film that can be used in the present invention is preferably produced by stretching after film formation by a solution casting film formation method. Moreover, it is preferable that a solution casting film is a multilayer casting film by co-casting simultaneously or sequentially. It is because it can be set as the film which has a desired retardation value.
In the present invention, the obtained cellulose acylate solution may be cast as a single layer liquid on a smooth band or drum as a metal support, or a plurality of cellulose acylate solutions of two or more layers may be cast. May be. When casting a plurality of cellulose acylate solutions, produce a film while casting and laminating a solution containing cellulose acylate from a plurality of casting openings provided at intervals in the traveling direction of the metal support. For example, the methods described in JP-A-61-158414, JP-A-1-122419, JP-A-11-198285 and the like can be applied. Further, it may be formed into a film by casting a cellulose acylate solution from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61-947245, It can be carried out by the methods described in JP-A Nos. 61-104813, 61-158413, and 6-134933. Further, a cellulose acylate film in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded. A casting method may be used. Furthermore, it is also a preferred embodiment that the outer solution described in JP-A-61-94724 and JP-A-61-94725 contains a larger amount of an alcohol component which is a poor solvent than the inner solution.

  Alternatively, by using two casting ports, the film cast on the metal support is peeled off by the first casting port, and the second casting is performed on the side in contact with the metal support surface. Further, a film may be prepared, for example, a method described in Japanese Patent Publication No. 44-20235. The cellulose ester solution to be cast may be the same solution or different cellulose acylate solutions, and is not particularly limited. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Further, the cellulose ester solution of the present invention can be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, etc.).

  In conventional single-layer liquids, it is preferable to extrude a cellulose acylate solution with a high concentration and a high viscosity in order to obtain the required film thickness. In this case, the stability of the cellulose acylate solution is poor and solids are generated. In many cases, however, it becomes a problem due to a failure or poor flatness. As a solution to this, by casting a plurality of cellulose acylate solutions from a casting port, a highly viscous solution can be extruded onto a metal support at the same time. Not only can it be produced, but also a concentrated cellulose acylate solution can be used to reduce the drying load and increase the film production speed.

  In the case of co-casting, the inner and outer thicknesses are not particularly limited, but preferably the outer side is preferably 1 to 50% of the total film thickness, and more preferably 2 to 30%. Here, in the case of co-casting with three or more layers, the total thickness of the layer in contact with the metal support and the layer in contact with the air side is defined as the outer thickness.

  In the case of co-casting, a cellulose acylate film having a laminated structure can be produced by co-casting cellulose acylate solutions having different degrees of substitution. Also, a cellulose acylate film having a laminated structure can be produced by co-casting cellulose acylate solutions having different additive concentrations such as plasticizer, ultraviolet absorber, and matting agent fine particles. For example, the matting agent fine particles can be contained in the outer layer in a large amount or only in the outer layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the outer layer, and may be contained only in the core layer. The type of plasticizer and ultraviolet absorber can be changed between the core layer and the outer layer. For example, the outer layer contains a low-volatility plasticizer and / or an ultraviolet absorber, and the core layer is a plasticizer with excellent plasticity. Alternatively, an ultraviolet absorber excellent in ultraviolet absorption can be added. Moreover, it is also a preferable aspect that a release agent is included only in the outer layer on the metal support side. Moreover, in order to cool a metal support body by a cooling drum method and gelatinize a solution, it is also preferable to add more alcohol which is a poor solvent to an outer layer than a core layer. The Tg of the outer layer and the core layer may be different, and the Tg of the core layer is preferably lower than the Tg of the outer layer. Further, the viscosity of the solution containing cellulose acylate during casting may be different between the outer layer and the core layer, and the viscosity of the outer layer is preferably smaller than the viscosity of the core layer, but the viscosity of the core layer is higher than the viscosity of the outer layer. It may be small.

{Stretching}
The retardation of the cellulose acylate film that can be used in the present invention can be adjusted by a stretching treatment. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284111, and JP-A-4-298310 can be used for positively stretching in the width direction (perpendicular to the conveying direction). And JP-A-11-48271. The stretching of the film can be carried out at room temperature or under heating conditions. The temperature during stretching is preferably 100 to 210 ° C, more preferably 120 ° C to 200 ° C, and further preferably 130 to 195 ° C.

The film may be stretched uniaxially only in the transport direction (TD) or in the width direction (MD, the direction orthogonal to the transport direction) or simultaneously or sequentially biaxially stretch, but it is preferable to stretch more in the TD direction. Stretching in the MD direction is preferably 1.0 to 1.3, and stretching in the TD direction is preferably 1.1 to 2.0 times, more preferably 1.15 to 1.9 times, and 1.15 to 1 .8 times is more preferable.
The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched.
When stretching is performed in the middle of the film forming process, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount = (residual volatile matter mass / heat-treated film mass) × 100% is 0.05. It can be preferably stretched at -50%.
In the case of stretching the film that has been formed and wound, it is preferable to stretch the film in the width direction 1.1 to 2.0 times in a state where the residual solvent amount is 0 to 5%.

In addition, the cellulose acylate film that can be used in the present invention may be biaxially stretched. Biaxial stretching includes simultaneous biaxial stretching and sequential biaxial stretching, but sequential biaxial stretching is preferred from the viewpoint of continuous production, and after casting the dope, the film is peeled off from the band or drum, After stretching in the width direction, the film is stretched in the longitudinal direction, or stretched in the longitudinal direction and then stretched in the width direction.
In order to relieve residual strain in stretching, reduce dimensional change, and to reduce variations in the width direction of the in-plane slow axis, it is preferable to provide a relaxation step after transverse stretching. In the relaxation step, it is preferable to adjust the width of the film after relaxation to a range of 100 to 70% (relaxation rate of 0 to 30%) with respect to the width of the film before relaxation. The temperature in the relaxation step is preferably an apparent glass transition temperature Tg-50 to Tg + 50 ° C. of the film. In normal stretching, in the relaxation rate zone after passing through this maximum widening rate, the time until it passes through the tenter zone is shorter than 1 minute.
Here, the apparent Tg of the film in the stretching process is that the film containing the residual solvent is enclosed in an aluminum pan, and the temperature is increased from 25 ° C. to 200 ° C. at 20 ° C./min with a differential scanning calorimeter (DSC). Tg was determined by obtaining an endothermic curve.

{Heat treatment process}
The method for producing a cellulose acylate film that can be used in the present invention preferably includes a heat treatment step after the drying step. The heat treatment in the heat treatment step may be performed after completion of the drying step, and may be performed immediately after the stretching / drying step. Alternatively, after the completion of the drying step, the material may be wound once by a method described later, and only the heat treatment step may be separately provided. . In the present invention, it is preferable to provide the heat treatment step again after the drying step is once cooled to room temperature to 100 ° C. or less. This is because a film having better thermal dimensional stability can be obtained. For the same reason, it is preferable that the amount of residual solvent is dried to less than 2% by mass, preferably less than 0.4% by mass immediately before the heat treatment step.
Although the reason why the shrinkage rate of the film can be reduced by such treatment is not clear, in the film that has undergone the treatment to be stretched in the stretching process, the residual stress in the stretching direction is large, so the residual stress is eliminated by heat treatment. Thus, it is presumed that the shrinkage force in the region below the heat treatment temperature is reduced.

The heat treatment is performed by a method of applying a wind at a predetermined temperature to the film being conveyed or a method using a heating means such as a microwave.
The heat treatment is preferably performed at a temperature of 150 to 200 ° C., more preferably 160 to 180 ° C. The heat treatment is preferably performed for 1 to 20 minutes, more preferably 5 to 10 minutes.
When the heat treatment temperature exceeds 200 ° C. for a long time, it may cause a problem because the amount of the plasticizer scattered in the film increases.

{Rewinding film}
As the winder for winding the obtained film, a commonly used winder can be used, such as a constant tension method, a constant torque method, a taper tension method, and a program tension control method with a constant internal stress. It can be wound up by a take-up method. In the optical film roll obtained as described above, the slow axis direction of the film is preferably ± 2 ° with respect to the winding direction (longitudinal direction of the film), and further within the range of ± 1 °. Preferably there is. Alternatively, it is preferably ± 2 degrees with respect to the direction perpendicular to the winding direction (film width direction), and more preferably within a range of ± 1 degree. In particular, the slow axis direction of the film is preferably within ± 0.1 degrees with respect to the winding direction (longitudinal direction of the film). Alternatively, it is preferably within ± 0.1 degrees with respect to the width direction of the film.

{Heating steam treatment}
In addition, the stretched film may be manufactured through a process of spraying water vapor heated to 100 ° C. or higher. By passing through this water vapor spraying step, the residual stress of the cellulose acylate film to be produced is relaxed, and the dimensional change is reduced, which is preferable. The temperature of the water vapor is not particularly limited as long as it is 100 ° C. or higher, but considering the heat resistance of the film, the temperature of the water vapor is 200 ° C. or lower.

  These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas.

[Additives used for cellulose acylate film]
{Polycondensed ester}
In this invention, it is preferable that the said cellulose acylate film contains the polycondensation ester whose average carbon number of a glycol unit is 2.3-3.0.
Here, as the polycondensation ester used as an additive (particularly, Rth control agent) of the optical compensation layer, for example, a mixture of an aliphatic dicarboxylic acid having 2 to 20 carbon atoms and an aromatic dicarboxylic acid having 8 to 20 carbon atoms. And those obtained by reaction with diols selected from aliphatic diols having 2 to 12 carbon atoms, alkyl ether diols having 4 to 20 carbon atoms and aromatic diols having 6 to 20 carbon atoms.
On the other hand, the polycondensation ester that can be used in the present invention is selected from the above-mentioned general polycondensation esters so that the average carbon number of the glycol unit is 2.3 to 3.0. By doing so, the crystallinity of the polycondensed esters in the cellulose acylate film and the pressure-sensitive adhesive layer can be controlled to suppress crystal precipitation, and the reduction in contrast after the wet heat durability test can be suppressed.

《Glycol unit》
The glycol unit of the polycondensation ester that can be used in the present invention has an average carbon number of 2.3 to 3.0, preferably 2.4 to 3.0, and preferably 2.5 to 3.0. More preferably.

  The glycol unit of a polycondensed ester that can be used in the present invention refers to a diol residue existing between adjacent ester bonds. Among these, the glycol unit of the polycondensed ester that can be used in the present invention is preferably an aliphatic diol residue, an alkyl ether diol residue, and an aromatic ring-containing diol residue, and is a fatty acid having 2 to 20 carbon atoms. More preferably, it is obtained by reacting a glycol selected from a group diol, an alkyl ether diol having 4 to 20 carbon atoms and an aromatic ring-containing diol having 6 to 20 carbon atoms.

Examples of the aliphatic diol having 2 to 20 carbon atoms include alkyl diols and alicyclic diols, such as ethylene glycol (1,2-ethanediol), propylene glycol (1,2-propanediol, 1,3-propanediol), 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2 -Dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3 Propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2, , 4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1, There are 12-octadecanediol and the like, and these glycols are used as one kind or a mixture of two or more kinds.
Preferred aliphatic diols include ethylene glycol (1,2-ethanediol), propylene glycol (1,2-propanediol, 1,3-propanediol), 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, more preferably ethylene glycol (1,2-ethanediol), propylene glycol (1,2-propanediol, 1,3-propanediol), 1,2-butanediol, , 3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1, -Hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, particularly preferably ethylene glycol (1,2-ethanediol) and propylene glycol (1,2-propanediol, 1,3-propane) Diol). That is, from the viewpoint of adjusting the average carbon number of the glycol unit to 2.3 to 3.0, the compatibility with the cellulose ester, and the optical expression from the viewpoint that the polycondensation ester includes an ethylene glycol unit and a polyethylene glycol unit. Particularly preferred. In addition, when propylene glycol contains only 1,2-propanediol, when ethylene glycol and propylene glycol are used in combination, the distance between the dicarboxylic acid units is made constant so that the carbon chain length of the glycol units is 2 carbon atoms. It is preferable from the viewpoint that the crystallization of the dicarboxylic acid unit can be easily suppressed.

Examples of the alkyl ether diol having 4 to 20 carbon atoms include polytetramethylene ether glycol, polyethylene ether glycol, polypropylene ether glycol, and combinations thereof. The average degree of polymerization is not particularly limited, but is preferably 2 to 20, more preferably 2 to 10, further 2 to 5, and particularly preferably 2 to 4. As examples of these, commercially useful polyether glycols typically include Carbowax resin, Pluronics resin and Niax resin.
The aromatic diol having 6 to 20 carbon atoms is not particularly limited, but hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol, 1,2-hydroxybenzene, 1,3-hydroxybenzene, 1,4-hydroxybenzene, 1 , 4-benzenedimethanol, preferably bisphenol A, 1,4-hydroxybenzene, and 1,4-benzenedimethanol.
These alkyl ether diols and aromatic diols can be used as a mixture with the aliphatic diol as long as the average carbon number range of the glycol unit of the polycondensation ester of the present invention is satisfied. In this case, you may make it satisfy | fill the range of the average carbon number of the glycol unit of the polycondensation ester of this invention by using the mixture of ethylene glycol and diethylene glycol, for example.

《Dicarboxylic acid unit》
The dicarboxylic acid unit of the polycondensed ester that can be used in the present invention refers to a dicarboxylic acid residue existing between adjacent ester bonds. Among these, the dicarboxylic acid unit of the polycondensed ester used in the present invention is preferably an aliphatic dicarboxylic acid residue or an aromatic dicarboxylic acid residue, and is an aliphatic dicarboxylic acid having 4 to 20 carbon atoms or 8 carbon atoms. More preferably, it is obtained by reacting -20 aromatic dicarboxylic acids.

The dicarboxylic acid unit of the polycondensed ester that can be used in the present invention may be an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, or a combination of both, and the combination is not particularly limited, There is no problem even if several kinds of ingredients are combined. The dicarboxylic acid unit of the polycondensed ester used in the present invention is preferably an aromatic dicarboxylic acid unit from the viewpoint of optical development and polarizer durability.
The glycol unit of the polycondensed ester used in the present invention preferably has a dicarboxylic acid unit having an average carbon number of 5.6 or more from the viewpoint of optical expression, and more preferably 5.6 to 8.0. It is particularly preferably 5.8 to 7.5.

Examples of the aliphatic dicarboxylic acid having 4 to 20 carbon atoms preferably used in the present invention include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid. , Sebacic acid, dodecanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.
Examples of the aromatic dicarboxylic acid having 8 to 20 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8 -Naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid.

  Among these, preferable aliphatic dicarboxylic acids are malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, and 1,4-cyclohexanedicarboxylic acid, and aromatic dicarboxylic acid is phthalic acid. Acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid. Particularly preferably, the aliphatic dicarboxylic acid component is succinic acid, glutaric acid, and adipic acid, and the aromatic dicarboxylic acid is phthalic acid, terephthalic acid, and isophthalic acid.

<Sealing>
Further, the both ends of the polycondensed ester may remain as a reaction product, but a so-called end-capping may be carried out by further reacting monocarboxylic acids, monoalcohols or phenols. It is effective in terms of storage stability that the end capping is performed in particular so as not to contain free carboxylic acids.
In the preferable aspect in this invention, it is preferable that the both-ends hydroxyl group blocking rate represented by following formula (4) of the said polycondensation ester is 70% or less. However, the terminal hydroxyl group here does not include -OH which is a part of the terminal carboxyl group (-COOH).
Formula (4):
Both-end hydroxyl group blocking ratio (%) = 100 × (total number of blocked hydroxyl groups present at both ends of polycondensation ester) / {(total number of unblocked hydroxyl groups present at both ends of polycondensation ester) + (Total number of blocked hydroxyl groups present at both ends of the polycondensation ester)}
The polycondensed ester preferably has a hydroxyl group blocking ratio of both terminals represented by the formula (4) of 70% or less, more preferably 60% or less, and particularly preferably 50% or less. preferable. Thus, by selecting a polycondensation ester in which the specific hydroxyl group blocking rate is further controlled from polycondensation esters in which the average carbon number of the glycol unit is 2.3 to 3.0, the hydrophilicity / hydrophobicity can be improved. Can be improved. On the other hand, the terminal carboxyl group blocking rate represented by the following formula (4 ′) of the polycondensed ester is preferably 70% or less, more preferably 60% or less, and 50% or less. It is particularly preferred.
Formula (4 ′):
Carboxyl group blocking rate (%) at both ends = 100 × (total number of blocked carboxyl groups present at both ends of polycondensed ester) / {(total number of unblocked carboxyl groups present at both ends of polycondensed ester) + (Total number of blocked carboxyl groups present at both ends of the polycondensed ester)}
Furthermore, both the hydroxyl group blocking rate and the both carboxyl group blocking rate of the polycondensed ester are both preferably 70% or less, more preferably 60% or less, and 50% or less. Is particularly preferred. Moreover, it is preferable that both ends of the polycondensed ester are hydroxyl groups rather than carboxyl groups.
In the present invention, a polycondensed ester in which both ends of the polycondensed ester are hydroxyl groups not sealed with an alkyl group or an aromatic group is particularly preferable from the viewpoints of compatibility and optical developability.

The polycondensation ester that can be used in the present invention can be protected with a monoalcohol residue or a monocarboxylic acid residue so that both ends do not become a carboxyl group or a hydroxyl group.
In this case, the monoalcohol is preferably a substituted or unsubstituted monoalcohol having 1 to 30 carbon atoms, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol. , Octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, aliphatic alcohol such as dodecaoctanol, allyl alcohol, oleyl alcohol, benzyl alcohol, 3-phenyl Examples thereof include substituted alcohols such as propanol.

  End-capping alcohols that can be preferably used are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol, isooctanol, 2-ethylhexyl alcohol, isononyl alcohol, oleyl alcohol Benzyl alcohol, in particular methanol, ethanol, propanol, isobutanol, cyclohexyl alcohol, 2-ethylhexyl alcohol, isononyl alcohol, benzyl alcohol.

  Moreover, when sealing with a monocarboxylic acid residue, the monocarboxylic acid used as a monocarboxylic acid residue is preferably a substituted or unsubstituted monocarboxylic acid having 1 to 30 carbon atoms. These may be aliphatic monocarboxylic acids or aromatic ring-containing carboxylic acids. Preferred aliphatic monocarboxylic acids are described, for example, acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid, and examples of the aromatic ring-containing monocarboxylic acid include Benzoic acid, p-tert-butylbenzoic acid, p-tert-amylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, etc. Yes, these can be used alone or in combination of two or more.

Such a polycondensed ester that can be used in the present invention is synthesized by heat melting by a polyesterification reaction or transesterification reaction between the above dicarboxylic acid and glycol and / or a monocarboxylic acid or monoalcohol for end-capping by a conventional method. It can be easily synthesized by either a condensation method or an interfacial condensation method of acid chlorides of these acids and glycols. The production methods of these polycondensed esters are described in detail in Koichi Murai, “Additives, Theory and Application” (Kokai Shobo Co., Ltd., first published on March 1, 1973). In addition, Japanese Patent Laid-Open Nos. 05-155809, 05-155810, Japanese Patent Laid-Open Nos. 05-97073, 2006-259494, 07-330670, 2006-342227, 2007-003679. The materials described in each publication can also be used.
Hereinafter, although the specific example of the polycondensation ester which can be preferably used for this invention is shown, the polycondensation ester which can be used by this invention is not limited to these.

（表中、ポリエステルポリオールは重縮合エステルのことを指す）。

(In the table, polyester polyol refers to polycondensed ester).

  In Table 1, EG represents ethylene glycol, PG represents propylene glycol, BG represents butylene glycol, TPA represents terephthalic acid, PA represents phthalic acid, AA represents adipic acid, and SA represents succinic acid. Yes.

  The amount of polycondensation ester used (may be the content) is preferably in the range of 3% by mass to 30% by mass, more preferably in the range of 5% by mass to 25% by mass, and particularly preferably. It is in the range of 5% by mass to 20% by mass.

  Although there is no restriction | limiting in particular in the molecular weight of the said polycondensation ester, It is preferable that it is 200-100000 by a weight average molecular weight, It is more preferable that it is 200-10000, It is especially preferable that it is 200-5000.

  The haze having a thickness of 80 μm of the polycondensed ester is preferably 5% or less, more preferably 4% or less, and particularly preferably 3% or less. In addition, the 80-micrometer-thick haze of the said polycondensation ester represents the haze when it measures by pinching between two glass plates of a 80-micrometer gap by the method mentioned later.

<ΔSP value>
In the present invention, it is preferable that the difference between the solubility parameter of the cellulose acylate and the solubility parameter of the polycondensed ester (hereinafter, the difference in solubility parameter is also referred to as ΔSP value) satisfies the following formula (5).
Formula (5):
| SP value (PP) -SP value (CA) | ≦ 1.5 MPa ^1/2
(In Formula (5), SP value (PP) represents the solubility parameter of the polycondensed ester measured by the Hoy method, and SP value (CA) represents the solubility parameter of the cellulose acylate measured by the Hoy method.)
When ΔSP of the cellulose acylate and the polycondensed ester is 1.5 or less, the compatibility between the cellulose acylate and the additive is improved, and whitening and crying are less likely to occur. The value of ΔSP is more preferably 1.3 or less, particularly preferably less than 1.3, and even more preferably less than 1.0.
When two or more types of additives are added to the cellulose acylate film, it is preferable that the ΔSP value of the additives other than the solubility parameter of the polycondensed ester and the cellulose acylate satisfy the above range.
Moreover, when adding 2 or more types of additives to the said cellulose acylate film, it is preferable to add between each additive and a cellulose acylate, and also (DELTA) SP value of additives satisfy | fill the said range. For example, when two additives are added, the difference between the SP value of the polycondensed ester and the SP value of the cellulose acylate, the difference between the second additive SP value and the SP value of the cellulose acylate, and the polycondensation It is preferable that three of the difference between the SP value of the ester and the SP value of the second additive satisfy the above range. That is, it is preferable that the difference between the maximum value and the minimum value of the solubility parameter (SP value) of each of the three measured by the Hoy method satisfies the following formula (5 ′).
Formula (5 ′): | SP value (maximum value) −SP value (minimum value) | <1.5 MPa ^1/2
Furthermore, the preferable range of the ΔSP value in the formula (5 ′) is the same as the preferable range of the formula (5).
The SP value in the present invention is a value calculated by the Hoy method, and the Hoy method is described in POLYMER HANDBOOK FOURTH EDITION.

[Retardation expression agent]
The cellulose acylate film that can be used in the present invention preferably contains at least one retardation enhancer in order to develop a retardation value. The retardation enhancer is not particularly limited, but is composed of a rod-shaped compound, a compound having a cyclic structure such as a cycloalkane or an aromatic ring, or a retardation among the non-phosphate ester compounds. The compound which shows expression property can be mentioned. As the compound having a cyclic structure, a discotic compound is preferable. As the rod-like compound or discotic compound, a compound having at least two aromatic rings can be preferably used as a retardation developer.
The addition amount of the retardation enhancer comprising a rod-shaped compound is preferably 0.1 to 30 parts by mass, and preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. Further preferred. The discotic compound contained in the retardation developer is preferably less than 3 parts by mass, more preferably less than 2 parts by mass, and less than 1 part by mass with respect to 100 parts by mass of the cellulose acylate. It is particularly preferred.
Since the discotic compound is superior to the rod-shaped compound in Rth retardation expression, it is preferably used when a particularly large Rth retardation is required. Two or more retardation developers may be used in combination.
The retardation developer preferably has a maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

The discotic compound will be described. As the discotic compound, a compound having at least two aromatic rings can be used.
In the present specification, the “aromatic ring” includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring.
The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).
The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
As the aromatic ring, a benzene ring, a condensed benzene ring, and biphenyls are preferable. In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, compounds disclosed in JP-A No. 2001-166144 are preferably used.

The number of carbon atoms of the aromatic ring in the retardation enhancer is preferably 2-20, more preferably 2-12, still more preferably 2-8, and 2-6. Most preferred.
The bonding relationship between two aromatic rings can be classified into (a) when a condensed ring is formed, (b) when directly linked by a single bond, and (c) when linked via a linking group (for aromatic rings). , Spiro bonds cannot be formed). The connection relationship may be any of (a) to (c).

  Examples of the condensed ring (a condensed ring of two or more aromatic rings) include an indene ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthylene ring, a biphenylene ring, a naphthacene ring, Pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline ring, isoquinoline Ring, quinolidine ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxathiin ring, phenoxazine ring and thiant It includes emissions ring. Naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring and quinoline ring are preferred.

  The single bond (b) is preferably a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded with two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between the two aromatic rings.

The linking group in (c) is also preferably bonded to carbon atoms of two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof. Examples of linking groups composed of combinations are shown below. In addition, the relationship between the left and right in the following examples of the linking group may be reversed.
c1: -CO-O-
c2: —CO—NH—
c3: -alkylene-O-
c4: —NH—CO—NH—
c5: —NH—CO—O—
c6: —O—CO—O—
c7: -O-alkylene-O-
c8: -CO-alkenylene-
c9: -CO-alkenylene-NH-
c10: -CO-alkenylene-O-
c11: -alkylene-CO-O-alkylene-O-CO-alkylene-
c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-
c13: -O-CO-alkylene-CO-O-
c14: -NH-CO-alkenylene-
c15: -O-CO-alkenylene-

The aromatic ring and the linking group may have a substituent.
Examples of substituents include halogen atoms (F, Cl, Br, I), hydroxyl groups, carboxyl groups, cyano groups, amino groups, nitro groups, sulfo groups, carbamoyl groups, sulfamoyl groups, ureido groups, alkyl groups, alkenyls. Group, alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamido group, aliphatic substituted amino group An aliphatic substituted carbamoyl group, an aliphatic substituted sulfamoyl group, an aliphatic substituted ureido group, and a non-aromatic heterocyclic group.

It is preferable that the alkyl group has 1 to 8 carbon atoms. A chain alkyl group is preferable to a cyclic alkyl group, and a linear alkyl group is particularly preferable. The alkyl group may further have a substituent (for example, a hydroxy group, a carboxy group, an alkoxy group, an alkyl-substituted amino group). Examples of alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, and 2- Each group of a diethylaminoethyl group is included.
The alkenyl group preferably has 2 to 8 carbon atoms. A chain alkenyl group is preferable to a cyclic alkenyl group, and a linear alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group, and a 1-hexenyl group.
The alkynyl group preferably has 2 to 8 carbon atoms. A chain alkynyl group is preferable to a cyclic alkynyl group, and a linear alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include ethynyl group, 1-butynyl group and 1-hexynyl group.

The number of carbon atoms in the aliphatic acyl group is preferably 1-10. Examples of the aliphatic acyl group include an acetyl group, a propanoyl group, and a butanoyl group.
The number of carbon atoms in the aliphatic acyloxy group is preferably 1-10. Examples of the aliphatic acyloxy group include an acetoxy group.
The number of carbon atoms of the alkoxy group is preferably 1-8. The alkoxy group may further have a substituent (for example, an alkoxy group). Examples of the alkoxy group (including a substituted alkoxy group) include a methoxy group, an ethoxy group, a butoxy group, and a methoxyethoxy group.
The number of carbon atoms of the alkoxycarbonyl group is preferably 2-10. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.
The number of carbon atoms of the alkoxycarbonylamino group is preferably 2-10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

The alkylthio group preferably has 1 to 12 carbon atoms. Examples of the alkylthio group include a methylthio group, an ethylthio group, and an octylthio group.
The alkylsulfonyl group preferably has 1 to 8 carbon atoms. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.
The number of carbon atoms in the aliphatic amide group is preferably 1-10. Examples of the aliphatic amide group include acetamide.
The number of carbon atoms of the aliphatic sulfonamide group is preferably 1-8. Examples of the aliphatic sulfonamido group include a methanesulfonamido group, a butanesulfonamido group, and an n-octanesulfonamido group.
The number of carbon atoms of the aliphatic substituted amino group is preferably 1-10. Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group, and a 2-carboxyethylamino group.
The number of carbon atoms in the aliphatic substituted carbamoyl group is preferably 2-10. Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.
The number of carbon atoms in the aliphatic substituted sulfamoyl group is preferably 1-8. Examples of the aliphatic substituted sulfamoyl group include a methylsulfamoyl group and a diethylsulfamoyl group.
The number of carbon atoms in the aliphatic substituted ureido group is preferably 2-10. Examples of the aliphatic substituted ureido group include a methylureido group.
Examples of the non-aromatic heterocyclic group include a piperidino group and a morpholino group.
The molecular weight of the retardation developer is preferably 300 to 800.

  As the discotic compound, a triazine compound represented by the following general formula (∨) is preferably used.

In the above general formula (∨):
R ²⁰¹ each independently represents an aromatic ring or a heterocyclic ring having a substituent in at least one of the ortho, meta and para positions.
X ²⁰¹ each independently represents a single bond or —NR ²⁰² —. Here, each R ²⁰² independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group, or a heterocyclic group.

The aromatic ring represented by R ²⁰¹ is preferably phenyl or naphthyl, particularly preferably phenyl. The aromatic ring R ²⁰¹ represents may have at least one substituent at any substitutable position. Examples of the substituent include halogen atom, hydroxyl group, cyano group, nitro group, carboxyl group, alkyl group, alkenyl group, aryl group, alkoxy group, alkenyloxy group, aryloxy group, acyloxy group, alkoxycarbonyl group, Alkenyloxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, alkyl-substituted sulfamoyl group, alkenyl-substituted sulfamoyl group, aryl-substituted sulfamoyl group, sulfonamide group, carbamoyl, alkyl-substituted carbamoyl group, alkenyl-substituted carbamoyl group, aryl-substituted carbamoyl group, amide Groups, alkylthio groups, alkenylthio groups, arylthio groups and acyl groups.

The heterocyclic group represented by ^R201 preferably has aromaticity. The heterocycle having aromaticity is generally an unsaturated heterocycle, preferably a heterocycle having the largest number of double bonds. The heterocyclic ring is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring. The hetero atom of the heterocyclic ring is preferably a nitrogen atom, a sulfur atom or an oxygen atom, and particularly preferably a nitrogen atom. As the heterocyclic ring having aromaticity, a pyridine ring (2-pyridyl or 4-pyridyl as the heterocyclic group) is particularly preferable. The heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the aryl moiety.
When X ²⁰¹ is a single bond, the heterocyclic group is preferably a heterocyclic group having a free valence on the nitrogen atom. The heterocyclic group having a free valence on the nitrogen atom is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and a 5-membered ring. Is most preferred. The heterocyclic group may have a plurality of nitrogen atoms. Further, the heterocyclic group may have a hetero atom other than the nitrogen atom (for example, O, S). Examples of heterocyclic groups having free valences on nitrogen atoms are shown below. Here, -C ₄ H ₉ ⁿ represents a n-C ₄ H _9.

The alkyl group represented by R ²⁰² may be a cyclic alkyl group or a chain alkyl group, but a chain alkyl group is preferable, and a linear alkyl group is more preferable than a branched chain alkyl group. preferable. The number of carbon atoms in the alkyl group is preferably 1-30, more preferably 1-20, further preferably 1-10, still more preferably 1-8, and 1-6. Most preferred. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (for example, methoxy group, ethoxy group) and an acyloxy group (for example, acryloyloxy group, methacryloyloxy group).

The alkenyl group represented by R ²⁰² may be a cyclic alkenyl group or a chain alkenyl group, but is preferably a chain alkenyl group and is more preferably a linear alkenyl group than a branched chain alkenyl group. More preferably it represents a group. The number of carbon atoms in the alkenyl group is preferably 2 to 30, more preferably 2 to 20, still more preferably 2 to 10, still more preferably 2 to 8, 6 is most preferred. The alkenyl group may have a substituent. Examples of the substituent are the same as those of the alkyl group described above.
The aromatic ring group and heterocyclic group represented by R ²⁰² are the same as the aromatic ring and heterocyclic ring represented by R ²⁰¹ , and the preferred range is also the same. The aromatic ring group and the heterocyclic group may further have a substituent, and examples of the substituent are the same as those of the aromatic ring and heterocyclic ring of ^R201 .

  The compound represented by the general formula (∨) can be synthesized by a known method such as the method described in JP-A-2003-344655. Details of the retardation enhancer are described on page 49 of published technical bulletin 2001-1745.

  As the retardation developing agent that can be used in the present invention, a polymer additive can be used as in the case of the low molecular weight compound. Here, in the present invention, the polymer used as the non-phosphate ester-based polymer may also function as a retardation developer. As the polymeric retardation developer which is also a non-phosphate ester polymer, the aromatic polyester polymer and copolymers of the aromatic polyester polymer and other resins are preferable.

  The retardation enhancer that can be used in the present invention is more preferably a Re enhancer from the viewpoint of efficiently expressing Re and realizing an appropriate Nz factor. Among the retardation developing agents, examples of the Re developing agent include a discotic compound and a rod-shaped compound.

As the retardation developing agent that can be used in the present invention, [Re developing agent] described in [0051] to [0098] of JP-A-2009-063983 can be used.

<Polarizer>
As a polarizer contained in the backlight side polarizing plate used in the present invention, the same polarizer as that used in the above-described viewing side polarizing plate can be used.

<Polarizing plate protective film contained in backlight side polarizing plate>
There is no restriction | limiting in particular in the polarizing plate protective film contained in the backlight side polarizing plate used for this invention, The thing similar to the polarizing plate protective film contained in the visual recognition side polarizing plate mentioned above can be used.

  The thickness of the polarizing plate protective film contained in the backlight side polarizing plate is preferably 60 mμm or less from the viewpoint of thinning the polarizing plate. Preferably it is 50 micrometers or less, More preferably, it is 40 micrometers or less.

The moisture permeability at 40 ° C. and 90% RH of the polarizing plate protective film contained in the backlight side polarizing plate is preferably 50 g / m ² · day or less. More preferably, it is 40 g / m ² · day or less, and further preferably 30 g / m ² · day or less.
When a polarizing plate protective film having low moisture permeability is used, unevenness that occurs in a moist heat environment can be further suppressed.

  The polarizing plate protective film contained in the backlight side polarizing plate may be bonded to the polarizer via an adhesive, or may be formed directly or by transfer on the polarizer.

<Measurement of moisture permeability>
The moisture permeability of the polarizing plate protective film contained in the backlight side polarizing plate was measured by a method (40 ° C. and 90% RH) defined by a moisture permeability test method (cup method) of the JISZ0208 moisture-proof packaging material.

<Evaluation of retardation>
In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light is incident at a wavelength of λ nm from the inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction of the rotation axis of KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (in the absence of the slow axis, the arbitrary direction in the film plane is the rotation axis), Rth can also be calculated from the following formula (21) and formula (22) based on the value, the assumed value of the average refractive index, and the input film thickness value.

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

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

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is from −50 degrees to +50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) and the tilt axis (rotating axis). In each of the 10 degree steps, light of wavelength λ nm is incident from the inclined direction and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or WR is calculated.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59). The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

In this specification, the values of Re (450) and Re (550) are 3 or more different wavelengths (for example, λ = 479.2, 546.3, 632.8, 745.3 nm) depending on the measurement device. It is assumed that Re and Rth are calculated from each wavelength. These values are approximated by Cauchy's equation (up to the third term, Re = A + B / λ ² + C / λ ⁴ ) to obtain values A, B, and C. From the above, Re and Rth at the wavelength λ can be re-plotted, and Re (λ) at each wavelength λ can be obtained therefrom.

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

<Preparation of viewing side polarizing plate>
[Creation of protective film for polarizing plate]
The following composition was put into a mixing tank and stirred to dissolve each component, and a core layer cellulose acylate dope 1 was prepared.
-------------------------------------------------- -----------------------
Cellulose acetate having an acetyl substitution degree of 2.88 100 parts by mass ester oligomer (Compound 1-1) 10 parts by mass Durability improver (Compound 1-2) 4 parts by mass UV absorber (Compound 1-3) 3 parts by mass Methylene chloride (First solvent) 438 parts by mass Methanol (second solvent) 65 parts by mass
-------------------------------------------------- -----------------------

（０２６３）
［外層セルロースアシレートドープ１の作製］
上記のコア層セルロースアシレートドープ１９０質量部に下記のマット剤分散液１を１０質量部加え、外層セルロースアシレートドープ１を調製した。
-----------------------------------------------------------------------
平均粒子サイズ２０ｎｍのシリカ粒子
（ＡＥＲＯＳＩＬ Ｒ９７２、日本アエロジル（株）製） ２質量部
メチレンクロライド（第１溶媒） ７６質量部
メタノール（第２溶剤） １１質量部
コア層セルロースアシレートドープ１ １質量部
-----------------------------------------------------------------------

(0263)
[Preparation of outer layer cellulose acylate dope 1]
10 parts by mass of the following matting agent dispersion 1 was added to 190 parts by mass of the core layer cellulose acylate dope to prepare an outer layer cellulose acylate dope 1.
-------------------------------------------------- ---------------------
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass Core layer cellulose acylate dope 1 part by mass
-------------------------------------------------- ---------------------

[Production of cellulose acylate film]
Three layers of the core layer cellulose acylate dope 1 and the outer layer cellulose acylate dope 1 on both sides thereof were cast simultaneously on a drum at 20 ° C. from the casting port. The film was peeled off at a solvent content of about 20% by mass, both ends in the width direction of the film were fixed with a tenter clip, and dried while being stretched 1.2 times in the lateral direction with a residual solvent of 3 to 15% by mass. . Thereafter, a cellulose acylate film having a thickness of 25 μm was produced by conveying between rolls of a heat treatment apparatus, and a polarizing plate protective film 01 was obtained.

[Measurement of moisture permeability]
The moisture permeability of the protective film was measured by a method (40 ° C. and 90% RH) specified by a moisture permeability test method (cup method) of JISZ0208 moisture-proof packaging material. The moisture permeability of the polarizing plate protective film 01 was 980 g / m ² · day.

[Preparation of hard coat layer]
The following hard coat curable composition hard coat 1 was prepared as a coating solution for forming a hard coat layer.

  The hard coat 1 is applied onto the surface of the polarizing plate protective film 01 produced as described above, and then dried at 100 ° C. for 60 seconds. Irradiated and cured, a polarizing plate protective film 01 with a hard coat layer having a hard coat layer with a thickness of 5 μm was produced. The thickness of the hard coat layer was adjusted by using a slot die and adjusting the coating amount in a die coating method.

[Preparation of polarizing plate]
1) Saponification of film The polarizing plate protective film with hard coat layer 01 thus prepared was immersed in a 4.5 mol / L sodium hydroxide aqueous solution (saponification solution) adjusted to 37 ° C for 1 minute, and then the film was washed with water. Then, after being immersed in a 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, it was further passed through a washing bath. Then, draining with an air knife was repeated three times, and after dropping the water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified polarizing plate protective film 01 with a hard coat layer.
2) Production of Polarizer According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls, and a polarizer having a width of 1330 mm and a thickness of 15 μm was prepared. The polarizer thus produced was designated as a polarizer 1.
3) Bonding The polarizer 1 thus obtained and the saponified polarizing plate protective film 01 with a hard coat layer were bonded with a 3% aqueous solution of PVA (manufactured by Kuraray Co., Ltd., PVA-117H). As described above, a polarizing plate 01 with a single-sided protective film was prepared by laminating with a roll-to-roll so that the polarization axis and the longitudinal direction of the film were orthogonal to each other.
At this time, the polarizing plate protective film was laminated so that the cellulose acylate film side was the polarizer side.

[Formation of optical compensation layer made of horizontally aligned discotic liquid crystal compound]
The following compounds 3-1 to 3-6 were dissolved in methyl ethyl ketone to prepare a solid content concentration of 35%.
-------------------------------------------------- --------
Polymerizable liquid crystalline compound 3-1 86.7 parts by mass Compound 3-2 8.6 parts by mass Polymerization initiator: Compound 3-3 2.9 parts by mass Polymerization initiator: Compound 3-4 1.0 part by mass fluorine-containing Surfactant: Compound 3-5 0.8 parts by mass Adhesion improver: Compound 3-6 0.1 parts by mass
-------------------------------------------------- --------

The coating solution was applied and dried on the polarizer-side surface of the polarizing plate 01 with a single-side protective film prepared above. The discotic liquid crystalline compound was aligned by heating at 70 ° C. for 1 minute. Thereafter, an ultraviolet ray of 500 mJ / cm ² was immediately irradiated under a temperature condition of 70 ° C. to polymerize the discotic liquid crystalline compound, and the alignment state was fixed. The thickness of the formed optical compensation layer was 1.6 μm. The thickness of the optical compensation layer was measured with a laser film thickness meter. This was designated as an optical compensation layer 001, and the produced polarizing plate was designated as 1001.

[Measurement of optical properties]
An optical compensation layer 001 was formed on a glass substrate under the same conditions as in the examples, and the retardation of only the optical compensation layer was measured. The in-plane retardation (Re (550)) was 0.5 nm, and the retardation in the film thickness direction (Rth (550)) was 120 nm. The refractive index was 1.58.

  On the polarizing plate 01 with a single-sided protective film, optical compensation layers 002 to 005 were prepared by changing only the film thickness as shown in Table 3 below under the same conditions as the optical compensation layer 001. .

[Production of Optical Compensation Layer 006]
The following composition was put into a mixing tank and stirred to dissolve each component, and a core layer cellulose acylate dope 2 was prepared.
-------------------------------------------------- -----------------------
Cellulose acetate having an acetyl substitution degree of 2.43 100 parts by mass The following ester oligomer (Compound 4-1) 19 parts by mass The following retardation modifier (Compound 4-2) 5 parts by mass Methylene chloride (first solvent) 471 parts by mass Methanol ( Second solvent) 70 parts by mass
-------------------------------------------------- -----------------------

(Compound 4-1)

[Preparation of Matting Agent Dispersion 2]
Next, the following components including the core layer cellulose acylate dope 2 prepared by the above method were charged into a disperser to prepare a mat agent dispersion 2.
-------------------------------------------------- -------------------------
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.2 parts by mass Methylene chloride (first solvent) 72.4 parts by mass Methanol (second solvent) 10.8 parts by mass Core layer cellulose reed Rate dope 2 10.3 parts by mass
-------------------------------------------------- -------------------------

  100 parts by mass of the core layer cellulose acylate dope 2 and the matting agent dispersion 2 were mixed in an amount such that the silica fine particles were 0.02 parts by mass with respect to the cellulose acylate to prepare a dope for film formation.

[Production of cellulose acylate film]
Three layers of the core layer cellulose acylate dope 2 and the outer layer cellulose acylate dope 2 on both sides thereof were cast simultaneously on a drum at 20 ° C. from the casting port. The film was peeled off in a state where the solvent content was about 20% by mass, conveyed with a pass roll, dried at 120 ° C. for 20 minutes, and wound up to produce an optical compensation layer 006. The film thickness was 40 μm, Re (550) = 1 nm, and Rth (550) = 120 nm. The refractive index was 1.48.

[Preparation of polarizing plate]
An optical compensation layer 006 saponified under the same conditions as the polarizing plate protective film 01 and a saponified polarizing plate protective film 01 with a hard coat layer are sandwiched between PVA (Kuraray Co., Ltd.) with the polarizer 1 interposed therebetween. Manufactured, PVA-117H) 3% aqueous solution was used as an adhesive, and a polarizing plate 1006 was produced by laminating with a roll-to-roll so that the polarizing axis and the longitudinal direction of the film were orthogonal.
At this time, it bonded together so that the cellulose acylate film side of a polarizing plate protective film might become a polarizer side.

＜バックライト側偏光板の作製＞
（光学補償膜の作製）

<Preparation of backlight-side polarizing plate>
(Preparation of optical compensation film)

  The optical compensation film 201 was produced by the following method.

[Production of Optical Compensation Layer 201]
The following composition was put into a mixing tank and stirred to dissolve each component, and a core layer cellulose acylate dope 3 was prepared. In the same manner as the optical compensation layer 006, the matting agent dispersion 3 was mixed with cellulose acylate in an amount that 0.02 parts by mass of silica fine particles to prepare an outer layer cellulose acylate dope 3.
-------------------------------------------------- -----------------------
Cellulose acetate having a degree of acetyl substitution of 2.43 100 parts by mass The following ester oligomer (Compound 4-1) 19 parts by mass Methylene chloride (first solvent) 471 parts by mass Methanol (second solvent) 70 parts by mass
-------------------------------------------------- -----------------------

[Production of cellulose acylate film]
The core layer cellulose acylate dope 3 and the outer layer cellulose acylate dope 3 on both sides of the core layer cellulose acylate dope 3 were simultaneously cast on a drum at 20 ° C. from the casting port. It peeled off in the state of solvent content rate of about 20 mass%, conveyed the pass roll, dried at 120 degreeC for 20 minutes, and wound up. The obtained film was further stretched 85% at a stretching temperature of 185 ° C. in a direction (TD) perpendicular to the film transport direction (MD) using a tenter. The produced film was used as the optical compensation layer 201. The film thickness was 40 μm, Re (550) = 110 nm, and Rth (550) = 100 nm. The ratio of Re at 450 nm to Re at 550 nm (Re (450) / Re (550)) was 1.02. The refractive index was 1.48.
[Preparation of polarizing plate]
The optical compensation layer 201 saponified under the same conditions as the polarizing plate protective film 01 and the saponified polarizing plate protective film 01 with a hard coat layer are sandwiched between PVA (Kuraray Co., Ltd.) with the polarizer 1 interposed therebetween. Manufactured, PVA-117H) 3% aqueous solution was used as an adhesive, and a polarizing plate 2001 was prepared by laminating with a roll-to-roll so that the polarizing axis and the longitudinal direction of the film were orthogonal.
At this time, the polarizing plate protective film was laminated so that the cellulose acylate film side was the polarizer side.

[Production of Optical Compensation Layers 202 to 205]
As shown in Table 4, optical compensation layers 202 to 205 having different Re and Rth were prepared in the same manner as the optical compensation layer 201 except for the stretching temperature and magnification.

  Instead of the optical compensation layer 201, except that the optical compensation layers 202 to 205 were used, bonding was performed in the same manner as the polarizing plate 2001 to produce polarizing plates 2002 to 2005.

<Preparation of backlight-side polarizing plate>
[Formation of Polarizing Plate Protective Film 02]
A ZEONOR film ZF14-040 (manufactured by Nippon Zeon Co., Ltd.) was used as the polarizing plate protective film 02 as the polarizing plate protective film of the backlight side polarizing plate. The moisture permeability was 1 g / m 2 · day.

[Preparation of polarizing plate]
On the polarizing plate protective film 02, the following UV curable adhesive is applied using a micro gravure coater (gravure roll: # 300, rotational speed 140% / line speed) so that the thickness is 5 μm. A film was obtained. Subsequently, this was bonded to the polarizer 1 immersed in the polyvinyl alcohol adhesive together with the polarizing plate protective film 02 and the saponified optical compensation layer 201 by a roll machine.

{UV curing adhesive}
-------------------------------------------------- --------------------
2-hydroxyethyl acrylate 100 parts by mass Ditrimethylolpropane tetraacrylate (manufactured by Sartomer Japan, trade name SR355) 11 parts by mass
-------------------------------------------------- --------------------

  Electron beams were applied from both sides of the bonded film to obtain a polarizing plate 2006 having films on both sides of the polarizer. The line speed was 20 m / min, the acceleration voltage was 250 kV, and the irradiation dose was 20 kGy.

[Production of Optical Compensation Layers 206 and 207]
Film sample No. described in Examples of JP-A-2009-063983. 111 was prepared as the optical compensation layer 206. The film thickness was 55 μm, Re (550) = 95 nm, Rth (550) = 130 nm, and Re (450) / Re (550) = 0.83. Further, the optical compensation layer 207 having a film thickness of 53 μm, Re (550) = 110 nm, and Rth (550) = 120 nm was produced by changing the stretching temperature and the magnification.

  Instead of the optical compensation layer 201, the optical compensation layers 206 and 207 were used, except that the polarizing plates 2006 and 2008 were obtained by pasting in the same manner as the polarizing plate 2006.

[Production of Optical Compensation Layer 208]]
On a saponified triacetyl cellulose film (TD80UL, manufactured by Fuji Film Co., Ltd.), a diluted solution of polyvinyl alcohol (MP-203 manufactured by Kuraray Co., Ltd.) is spin-coated to form an alignment film and subjected to a rubbing treatment. did. On the alignment film, a coating solution having the following composition is continuously applied using a bar coater, dried and heated (alignment aging) to horizontally align the liquid crystal,
Further, an optical compensation layer 208 having a thickness of 1.0 μm was formed by ultraviolet irradiation. Re (550) was 130 nm and Rth (550) = 65 nm. The refractive index was 1.58. When the tilt angle was measured by applying the crystal rotation method, it was confirmed that it was horizontally oriented. The retardation ratio (Re (450) / Re (550)) measured at each wavelength of 450 nm and 550 nm was 1.05.

Coating liquid composition of optical compensation layer 208
-------------------------------------------------- ------------------------------
Rod-like liquid crystal compound: Compound 5-1 13.0 parts by mass Sensitizer: Compound 5-2 0.13 parts by mass Polymerization initiator: Compound 5-3 0.39 parts by mass Fluorine-containing surfactant: Compound 5-40 .13 parts by mass Methyl ethyl ketone 86.4 parts by mass
-------------------------------------------------- ------------------------------

The polarizing plate protective film 01, the polarizer 1, and the optical compensation layer 208 were bonded together in the same manner as the polarizing plate 1006 to obtain a polarizing plate 2009.
At this time, the optical compensation layer was laminated so that the triacetyl cellulose film side and the cellulose acylate film side of the polarizing plate protective film 01 were respectively on the polarizer side.

<Production of liquid crystal display device>
The polarizing plate on the front and back of the VA mode liquid crystal display device (39E61HR, manufactured by SKYWORKH) and the retardation plate are peeled off, and the viewing side polarizing plate and the backlight side polarizing plate of the present invention are bonded so that the absorption axes are orthogonal to each other. Cells 3001 to 3016 were produced.

<Evaluation of liquid crystal display device>
[Evaluation of front contrast]
The black luminance and white luminance in the front direction were measured using a measuring device (EZ-Contrast XL88, manufactured by ELDIM) during black display in a dark room. White brightness / black brightness was defined as front contrast.
Front contrast is 3000 or more: A
Front contrast is 3000 or less: B
Each liquid crystal display device was evaluated.

[Evaluation of oblique light leakage and color]
The liquid crystal TV was turned on during black display in a dark room, and light leakage and color change in an oblique direction were observed.
(Evaluation criteria for light leakage)
A: Light leakage is hardly visually recognized even in a region where the polar angle is larger than 60 degrees.
B: Significant light leakage is observed even in a region where the polar angle is less than 60 degrees.

[Evaluation criteria for color shift]
A: Almost no coloring is observed in all polar and azimuthal directions.
B: Slight tint is observed when rotated by 360 degrees around the normal line of the liquid crystal cell in the polar angle direction of 60 degrees.
C: Coloring is observed when the polar angle is rotated by 360 degrees around the normal line of the liquid crystal cell in the direction of 60 degrees.

[Evaluation of unevenness]
{Unevenness immediately after Dry}
The produced liquid crystal display device was put in a 50 ° C. and 90% RH environment for 24 hours, and then put in a 40 ° C. and 10% RH environment for 2 hours.
Immediately after the liquid crystal display device was turned on, unevenness was observed from the front direction during black display in a dark room. The brightness of the uneven portion where light leakage occurred was measured with BM5A (manufactured by TOPCON) and evaluated as follows. A, B, and C are assumed to have no practical problem.
Less than 0.1 cd / m ² : A
0.1 cd / m ² or more and less than 0.3 cd / m ² : B
Less than 0.5 cd / m ² : C
0.5 cd / m ² or more: D

{Unevenness after continuous lighting}
Furthermore, it was continuously lit for 20 hours in an environment of 25 ° C. and 60%, and unevenness was observed from the front direction when displaying black in a dark room. The brightness of the uneven portion where light leakage occurred was measured with BM5A (manufactured by TOPCON) and evaluated as follows. A, B, and C are assumed to have no practical problem.
Less than 0.1 cd / m ² : A
0.1 cd / m ² or more and less than 0.3 cd / m ² : B
Less than 0.5 cd / m ² : C
0.5 cd / m ² or more: D

  The liquid crystal cells 3017 to 3018 were prepared in the same manner as in Example 5 and Example 9 so that the viewing side polarizing plate was on the backlight side, the backlight side polarizing plate was on the viewing side, and the absorption axes were orthogonal to each other. evaluated.

Claims (5)

A VA mode liquid crystal display device in which a pair of polarizing plates whose absorption axes are orthogonal to each other are arranged with a liquid crystal cell sandwiched between them, the polarizing plate on the viewing side in order from the liquid crystal cell side, the optical compensation layer, the polarizer, and the polarizing plate protection The optical compensation layer has a thickness of 10 μm or less, Rth (550) is 35 nm to 200 nm, and the backlight side polarizing plate is sequentially arranged from the liquid crystal cell side to the optical compensation layer, the polarizer, and the polarizing plate. A VA mode liquid crystal display device having a protective film, wherein the optical compensation layer has a thickness of 10 μm to 60 μm and satisfies the following formulas (1) and (2).
Formula (1) 30 nm ≦ Re (550) ≦ 200 nm
Formula (2) 50 nm ≦ Rth (550) ≦ 400 nm
(Re (550) represents in-plane retardation at a wavelength of 550 nm, and Rth (550) represents retardation in the thickness direction at a wavelength of 550 nm.) A VA mode liquid crystal display device in which a pair of polarizing plates whose absorption axes are orthogonal to each other are arranged with a liquid crystal cell sandwiched between them, the polarizing plate on the viewing side in order from the liquid crystal cell side, the optical compensation layer, the polarizer, and the polarizing plate protection The optical compensation layer has a thickness of 10 μm or less, Rth (550) is 35 nm to 220 nm, and the backlight side polarizing plate is sequentially arranged from the liquid crystal cell side to the optical compensation layer, the polarizer, and the polarizing plate. A VA mode liquid crystal display device having a protective film, wherein the optical compensation layer has a thickness of 10 μm to 60 μm and satisfies the following formulas (1) and (2).
Formula (1) 30 nm ≦ Re (550) ≦ 200 nm
Formula (2) 50 nm ≦ Rth (550) ≦ 400 nm
(Re (550) represents in-plane retardation at a wavelength of 550 nm, and Rth (550) represents retardation in the thickness direction at a wavelength of 550 nm.) The optical compensation layer included in the polarizing plate on the viewing side has a horizontally aligned discotic liquid crystalline compound, and is formed directly on the polarizer or via an alignment film. VA mode liquid crystal display device. The VA mode liquid crystal display device according to claim 1, wherein an optical compensation layer contained in the backlight-side polarizing plate satisfies the following formula (3).
Formula (3) 0.5 ≦ Re (450) / Re (550) ≦ 1.0 The thickness of the polarizing plate protective film contained in the polarizing plate on the backlight side is 60 μm or less, and the moisture permeability at 40 ° C. and 90% RH is 50 g / m ² · day or less. The VA mode liquid crystal display device described in 1.