JP2006257143A - Cellulose acylate film, polarizing plate using the same and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent cellulose acylate film having small optical anisotropy (Re, Rth) and small variation of optical performance with time to environmental change, to provide an optical material such as an optical compensation film and a polarizing plate produced from such a cellulose acylate film, and to provide a liquid crystal display device having a wide viewing angle and a high display quality. <P>SOLUTION: The cellulose acylate film contains at least one retardation regulator and at least one hydrophobicity-developing compound having at least one hydrogen bond-donating group and having an octanol/water distribution coefficient (log P) of 1-8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cellulose acylate film, and a polarizing plate and a liquid crystal display device using the same.

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

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

  So far, cellulose acylate films having a small front Re have been known. However, it was difficult to produce a cellulose acylate film having a small Re change depending on the angle, that is, a small Rth. There is a strong demand for an optically isotropic optically transparent film in which Re on the front surface of the cellulose acylate film is almost zero and the change in retardation angle is small, that is, Rth is also almost zero.

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

In addition, recent liquid crystal display devices have made remarkable developments, particularly in East Asia, mainly in home television. These regions are rich in seasonal changes, and the humidity change is large in the summer and winter (or rainy and dry seasons), so that there is a strong demand for liquid crystal display devices that the optical performance changes with time with respect to environmental changes. Yes.
JP 2001-247717 A Plastic Materials Course, Volume 17, Nikkan Kogyo Shimbun, “Fiber-Based Resin”, p. 121 (Showa 45)

An object of the present invention is to provide an excellent cellulose acylate film having a small optical anisotropy (Re, Rth) and a small change in optical performance over time with respect to environmental changes.
A further object of the present invention is to provide an optical material such as a polarizing plate produced from a cellulose acylate film having small optical anisotropy and excellent durability against environmental changes, and a wide viewing angle using these. An object is to provide a liquid crystal display device with high display quality.

  As a result of intensive studies, the present inventors have achieved the object of the present invention with the cellulose acylate film described below.

[1] Contain at least one retardation regulator, at least one hydrogen bond donating group, and at least one compound that exhibits hydrophobicity with an octanol / water partition coefficient (log P) of 1 or more and 8 or less A cellulose acylate film characterized by comprising:

[2] The cellulose acylate film according to [1], wherein the retardation regulator is at least one selected from compounds represented by the following general formulas (1) to (6).
General formula (1):

{In General Formula (1), R ¹¹ represents an aryl group. R ¹² and R ¹³ each independently represents an alkyl group or an aryl group, and at least one of them is an aryl group. Moreover, the alkyl group and the aryl group may each have a substituent. }
General formula (2):

{In General Formula (2), R ²¹ , R ²² and R ²³ each independently represents an alkyl group. Moreover, each alkyl group may have a substituent. }
General formula (3):

{In General Formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each represent a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. X ³¹ , X ³² , X ³³ and X ³⁴ are each a single bond, —CO— and NR ³⁵ — (R ³⁵ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group). Represents a divalent linking group formed from one or more groups selected from the group consisting of: a, b, c and d are integers of 0 or more, and a + b + c + d is 2 or more. Z ³¹ represents an (a + b + c + d) -valent organic group (excluding a cyclic group). }
General formula (4):

{In General Formula (4), R ⁴¹ represents an alkyl group or an aryl group, and R ⁴² and R ⁴³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. The total number of carbon atoms of R ⁴¹ , R ⁴² and R ⁴³ is 10 or more. }
General formula (5):

{In General Formula (5), R ⁵¹ and R ⁵² each independently represents an alkyl group or an aryl group. The total number of carbon atoms of R ⁵¹ and R ⁵² is 10 or more. }
General formula (6):

{In General Formula (6), R ⁶¹ represents a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group, and R ⁶² represents a hydrogen atom, a substituted or unsubstituted aliphatic group, Represents an unsubstituted aromatic group. L ⁶¹ represents a divalent to hexavalent linking group, and e represents an integer of 2 to 6 depending on the valence of L ⁶¹ . }

[3] The cellulose acylate film according to the above [2], wherein the retardation regulator is at least one selected from the compounds represented by the general formulas (1) to (3).

[4] The cellulose acylate film according to any one of [1] to [3], wherein the compound that exhibits hydrophobicity is represented by the following general formula (7).
General formula (7):

{In General Formula (7), ^X71 represents a boron atom, C- ^R71 ( ^R71 represents a hydrogen atom or a substituent), or a nitrogen atom. R ⁷¹¹ , R ⁷¹² , R ⁷¹³ , R ⁷¹⁴ , R ⁷¹⁵ , R ⁷²¹ , R ⁷²² , R ⁷²³ , R ⁷²⁴ , R ⁷²⁵ , R ⁷³¹ , R ⁷³² , R ⁷³³ , R ⁷³⁴ , and R ⁷³⁵ are each independently Represents a hydrogen atom or a substituent}

[5] The cellulose acylate film according to any one of the above [1] to [4], wherein Rth and Re at a wavelength of 630 nm of the cellulose acylate film satisfy the range of the following formula (1).
Formula (1): −25 nm ≦ Rth ₆₃₀ ≦ 25 nm and 0 nm ≦ Re ₆₃₀ ≦ 10 nm
[6] The cellulose according to any one of [1] to [5] above, wherein in the wavelength range of 400 nm to 700 nm, the Rth variation of the cellulose acylate film is 25 nm or less and the Re variation is 10 nm or less. Acylate film.

[7] The cellulose according to any one of the above [1] to [6], wherein the values of Re and Rth at a wavelength of 630 nm of the cellulose acylate film satisfy at least one of the following formulas (2) and (3): Acylate film.
Formula (2): | Re ₆₃₀ × Rth ₆₃₀ | ≦ 200
Formula (3): 0.5 ≦ Rth ₆₃₀ / Re ₆₃₀ ≦ 5.0 (where Re ₆₃₀ ≧ 1)

[8] The cellulose acylate film according to any one of the above [1] to [7], wherein the values of Re and Rth at a wavelength of 630 nm of the cellulose acylate film satisfy the relationship of the following formula (4).
Formula (4): | Re _{630 (max)} −Re _{630 (min)} | ≦ 5 and | Rth _{630 (max)} −Rth _{630 (min)} | ≦ 10
{In the formula, Re _{630 (max)} and Rth _{630 (max)} are the maximum retardation values at a wavelength of 630 nm of an arbitrarily cut out 1 m square film, and Re _{630 (min)} and Rth _{630 (min)} are the minimum at a wavelength of 630 nm. It is a retardation value. }

[9] The cellulose acylate constituting the cellulose acylate film has an acyl substitution degree of 2.50 to 3.00 and an average degree of polymerization of 180 to 700. The cellulose acylate film described.
[10] The acyl substituent of the cellulose acylate constituting the cellulose acylate film consists essentially of an acetyl group, the total degree of substitution is 2.50 to 2.95, and the average degree of polymerization is 180 to 550. The cellulose acylate film according to any one of the above [1] to [9].

[11] The cellulose acylate film according to any one of the above [1] to [10], wherein the film thickness of the cellulose acylate film is 10 to 120 μm.
[12] The cellulose acylate film according to any one of [1] to [11], wherein an equilibrium water content at 25 ° C. and 80% RH is 3.2% or less.
[13] The cellulose reed according to any one of [1] to [12] above, wherein the moisture permeability for 24 hours at 60 ° C. and 95% RH is 400 to 2000 g / m ² · 24 h in terms of a film thickness of 80 μm. Rate film.

[14] The cellulose acylate film according to any one of [1] to [13], which has a hygroscopic expansion coefficient of 30 × 10 ⁻⁵ /% RH or less.
[15] The cellulose acylate film is obtained by stretching, and the stretching ratio is 101% or more and 200% or less in a direction perpendicular to the transport direction (width direction). [14] The cellulose acylate film according to any one of [14].

[16] The cellulose acylate film according to the above [15], wherein the cellulose acylate film obtained by stretching satisfies a relationship represented by the following formula (5).
Formula (5): | Re _(n) −Re ₍₀₎ | /n≦1.0
{In the formula, Re _(n) is Re of a film stretched by n (%), and Re ₍₀₎ is Re of a film not stretched. }

[17] A polarizing plate in which a protective film is bonded to both sides of a polarizer, wherein at least one of the protective films is the cellulose acylate film according to any one of [1] to [16]. A polarizing plate.

[18] A liquid crystal display device comprising a liquid crystal cell and two polarizing plates disposed on both sides thereof, wherein at least one polarizing plate is the polarizing plate described in [17].
[19] The liquid crystal display device according to the above [18], wherein the liquid crystal display device is in an IPS mode.

  According to the research of the present inventors, it is possible to produce a cellulose acylate film having small optical anisotropy Re and Rth and excellent wet heat durability, and using this cellulose acylate film, an optical compensation film and a polarizing plate It has become possible to provide optical materials such as these and liquid crystal display devices using them.

<Cellulose acylate film>
[Retardation regulator]
The cellulose acylate film of the present invention preferably contains at least one retardation modifier selected from the general formulas (1) to (6). Below, the retardation regulator represented by general formula (1)-(6) used by this invention is demonstrated in detail.

First, the compound represented by the general formula (1) will be described in detail.
General formula (1):

In the above general formula (1), R ¹¹ represents an aryl group. R ¹² and R ¹³ each independently represents an alkyl group or an aryl group, and at least one of them is an aryl group. When R ¹² is an aryl group, R ¹³ may be an alkyl group or an aryl group, but is more preferably an alkyl group. Here, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and 1 to 12 carbon atoms. Is most preferred. The aryl group preferably has 6 to 36 carbon atoms, and more preferably 6 to 24 carbon atoms.

Next, the compound represented by the general formula (2) will be described in detail.
General formula (2):

In the general formula (2), R ²¹ , R ²² and R ²³ each independently represents an alkyl group. Here, the alkyl group may be linear, branched or cyclic. R ²¹ is preferably a cyclic alkyl group, and more preferably at least one of R ²² and R ²³ is a cyclic alkyl group. The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 12 carbon atoms. As the cyclic alkyl group, a cyclohexyl group is particularly preferable.

  The alkyl group and aryl group in the general formulas (1) and (2) may each have a substituent. Substituents include halogen atoms (for example, chlorine, bromine, fluorine and iodine), alkyl groups, aryl groups, alkoxy groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyloxy groups, sulfonylamino groups, A hydroxy group, a cyano group, an amino group and an acylamino group are preferred, more preferably a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a sulfonylamino group and an acylamino group, particularly preferably an alkyl group and an aryl group. A sulfonylamino group and an acylamino group.

Next, although the preferable example of a compound represented by General formula (1) or (2) is shown below, this invention is not limited to these specific examples.
In addition, the compound attached | subjected with (A-) is a specific example of a compound represented with General formula (1), and the compound attached | subjected with (B-) is compound represented with General formula (2). This is a specific example.

  Any of the above compounds can be produced by a known method. That is, the compounds of the general formula (1) and the general formula (2) are obtained by dehydration condensation reaction between carboxylic acids and amines using a condensing agent {for example, dicyclohexylcarbodiimide (DCC), etc., or carboxylic acid chloride derivatives and amines. It can be obtained by a substitution reaction with a derivative.

Next, the compound represented by the general formula (3) will be described.
General formula (3):

In the general formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each represent a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group, and an aliphatic group Is preferred. The aliphatic group may be linear, branched or cyclic, and more preferably cyclic. Examples of the substituent that the aliphatic group and the aromatic group may have include the substituent T described later, but an unsubstituted one is preferable.

X ³¹ , X ³² , X ³³ and X ³⁴ are each a single bond, —CO— and NR ³⁵ — (R ³⁵ represents a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group; It represents a divalent linking group formed from one or more groups selected from the group consisting of unsubstituted and / or aliphatic groups. The combination of X ³¹ , X ³² , X ³³ and X ³⁴ is not particularly limited, but is more preferably selected from —CO— and —NR ³⁵ —. a, b, c and d are integers of 0 or more, preferably 0 or 1, a + b + c + d is 2 or more, preferably 2 to 8, more preferably 2 to 6, further preferably 2-4. Z ³ represents an (a + b + c + d) -valent organic group (excluding a cyclic group). Z valence of ^3, preferably from 2 to 8, more preferably 2 to 6, preferably 2 to 4 further 2 or 3 being most preferred. An organic group refers to a group composed of an organic compound.

Moreover, as said general formula (3), Preferably it is a compound represented by the following general formula (3-1).
Formula (3-1): R ³¹¹ -X ³¹¹ -Z ³¹¹ -X ³¹² -R ³¹²

In the general formula (3-1), R ³¹¹ and R ³¹² each represent a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group, and an aliphatic group is preferable. The aliphatic group may be linear, branched or cyclic, and more preferably cyclic. Examples of the substituent that the aliphatic group and the aromatic group may have include the substituent T described later, but an unsubstituted one is preferable. X ³¹¹ and X ³¹² each independently represent —CONR ³¹³ — or —NR ³¹⁴ CO—, wherein R ³¹³ and R ³¹⁴ represent a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. More preferred are unsubstituted and / or aliphatic groups. Z ³¹¹ is a divalent group formed from one or more groups selected from —O—, —S—, —SO—, —SO ₂ —, —CO—, —NR ³¹⁵ —, an alkylene group, and an arylene group. Represents an organic group (excluding cyclic ones). The combination of Z ³¹¹ is not particularly limited, but is preferably selected from —O—, —S—, —NR ³¹⁵ —, and an alkylene group, more preferably selected from —O—, —S—, and an alkylene group. Most preferably, it is selected from among —, —O—, —S— and an alkylene group.

The general formula (3-1) is preferably a compound represented by the following general formulas (3-2) to (3-4).
Formula (3-2):

  General formula (3-3):

  General formula (3-4):

In the above general formulas (3-2) to (3-4), R ³²¹ , R ³²² , R ³²³ and R ³²⁴ each represent a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. An aliphatic group is preferred. The aliphatic group may be linear, branched or cyclic, and more preferably cyclic. Examples of the substituent that the aliphatic group and the aromatic group may have include the substituent T described later, but an unsubstituted one is preferable. Z ³²¹ is —O—, —S—, —SO—, —SO ₂ —, —CO—, —NR ³²⁵ — (R ³²⁵ is a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. An unsubstituted group and / or an aliphatic group is more preferable), a divalent linking group formed from one or more groups selected from an alkylene group and an arylene group. The combination of Z ³²¹ is not particularly limited, but is preferably selected from —O—, —S—, —NR ³²⁵ —, and an alkylene group, more preferably selected from —O—, —S—, and an alkylene group. Most preferably, it is selected from among —, —O—, —S— and an alkylene group.

Hereinafter, the substituted or unsubstituted aliphatic group will be described.
The aliphatic group may be linear, branched or cyclic, preferably having 1 to 25 carbon atoms, more preferably having 6 to 25 carbon atoms, particularly preferably having 6 to 20 carbon atoms. preferable. Specific examples of the aliphatic group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, t-butyl group, amyl group, isoamyl group, t- Amyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, bicyclooctyl group, adamantyl group, n-decyl group, t-octyl group, dodecyl group, hexadecyl group, octadecyl group, didecyl group, etc. Is mentioned.

Below, said aromatic group is demonstrated.
The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, and more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include benzene, naphthalene, anthracene, biphenyl, terphenyl, and the like. As the aromatic hydrocarbon group, benzene, naphthalene, and biphenyl are particularly preferable. As the aromatic heterocyclic group, those containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom are preferable. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, Examples thereof include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene and the like. As the aromatic heterocyclic group, pyridine, triazine, and quinoline are particularly preferable.

Moreover, the said substituent T is demonstrated in detail below.
Examples of the substituent T include alkyl groups (preferably those having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, and a t-butyl group. , N-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl, cyclohexyl group, etc., alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 2 carbon atoms). For example, a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group, etc.), an alkynyl group (preferably having a carbon number of 2-20, more preferably 2-12, particularly preferably 2-8, For example, propargyl group, 3-pentynyl group, etc.), aryl group (preferably 6-30 carbon atoms, more preferably 6-2 carbon atoms)
0, particularly preferably 6 to 12, for example, phenyl group, biphenyl group, naphthyl group, etc., amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10, particularly preferably 0 to 6; For example, an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, etc.), an alkoxy group (preferably having a carbon number of 1-20, more preferably 1-12, particularly preferably 1-8, Methoxy group, ethoxy group, butoxy group, etc.), aryloxy group (preferably having 6-20 carbon atoms, more preferably 6-16, particularly preferably 6-12, such as phenyloxy group, 2-naphthyloxy group, etc. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. A zoyl group, a formyl group, a pivaloyl group, etc.), an alkoxycarbonyl group (preferably having a carbon number of 2-20, more preferably 2-16, particularly preferably 2-12, such as a methoxycarbonyl group, an ethoxycarbonyl group, etc.), An aryloxycarbonyl group (preferably having a carbon number of 7-20, more preferably 7-16, particularly preferably 7-10, such as a phenyloxycarbonyl group), an acyloxy group (preferably having a carbon number of 2-20, more preferably Is 2 to 16, particularly preferably 2 to 10, for example, an acetoxy group, a benzoyloxy group, etc.), an acylamino group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms). Acetylamino group, benzoylamino group, etc.), alkoxycarbonylamino (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms such as a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16, particularly preferably 7 to 12, for example, phenyloxycarbonylamino group, etc., sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, For example, methanesulfonylamino group, benzenesulfonylamino group, etc.), sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16, particularly preferably 0 to 12, such as sulfamoyl group, methylsulfamoyl group, Dimethylsulfamoyl group, phenylsulfamoyl group, etc.), carbamoyl group (Preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms such as carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group), alkylthio group (preferably carbon number) 1-20, more preferably 1-16, particularly preferably 1-12, for example, methylthio group, ethylthio group, etc., arylthio group (preferably having 6-20 carbon atoms, more preferably 6-16, particularly preferably 6-12, such as phenylthio group, sulfonyl group (preferably 1-20 carbon atoms, more preferably 1-16, particularly preferably 1-12, such as mesyl group, tosyl group, etc.), sulfinyl group (Preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Methanesulfinyl group, benzenesulfinyl group, etc.), ureido group (preferably having 1-20 carbon atoms, more preferably 1-16, particularly preferably 1-12, such as ureido group, methylureido group, phenylureido group) , Phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, such as diethyl phosphoric acid amide, phenylphosphoric acid amide), hydroxy group, mercapto group, halogen Atoms (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably carbon number) 1 to 30, more preferably 1 to 12, and examples of the hetero atom include a nitrogen atom and an acid. Atoms, sulfur atoms, specifically imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl groups (preferably C3-C40, More preferably, it is 3-30, Most preferably, it is 3-24, For example, a trimethylsilyl group, a triphenylsilyl group, etc.) etc. are mentioned. These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

Preferred examples of the compound represented by the general formula (3) are shown below, but the present invention is not limited to these specific examples.

  Any of the compounds used in the present invention can be produced from known compounds. The compound represented by any one of the general formulas (3) and (3-1) to (3-4) is obtained, for example, by a condensation reaction of carbonyl chloride and an amine.

Next, the compounds of the general formulas (4) and (5) will be described.
General formula (4):

In the general formula (4), R ⁴¹ represents an alkyl group or an aryl group, R ⁴² and R ⁴³ each independently represent a hydrogen atom, an alkyl group or an aryl group. Moreover, it is particularly preferable that the total number of carbon atoms of R ⁴¹ , R ⁴² and R ⁴³ is 10 or more.

  General formula (5):

In the general formula (5), R ⁵¹ and R ⁵² each independently represents an alkyl group or an aryl group. The total number of carbon atoms of R ⁵¹ and R ⁵² is 10 or more, and the alkyl group and the aryl group may each have a substituent.

  As the substituent, a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are preferable, and an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are particularly preferable.

  The alkyl group may be linear, branched, or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and 6 to 20 (for example, , Methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t-octyl, undecyl, dodecyl, Tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred.

  As the aryl group, those having 6 to 30 carbon atoms are preferable, and those having 6 to 24 carbon atoms (for example, phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, triphenylphenyl) are particularly preferable.

  Although the preferable example of a compound represented by General formula (4) or General formula (5) is shown below, this invention is not limited to these specific examples.

Hereinafter, the compound represented by formula (6) of the present invention will be described.
General formula (6):

In the general formula (6), R ⁶¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group, and R ⁶² represents a hydrogen atom, a substituted or unsubstituted aliphatic group, Represents an unsubstituted aromatic group. Examples of the substituent include the above-described substituent T (hereinafter, the same unless otherwise specified). L ⁶¹ represents a divalent to hexavalent linking group. The valence of L ⁶¹ is preferably 2 to 4, more preferably 2 or 3. e represents an integer of 2 to 6 according to the valence of L ⁶¹ , more preferably 2 to 4, and particularly preferably 2 or 3.
Two or more R ⁶¹ and R ⁶² contained in one compound may be the same or different. Preferably they are the same.

The general formula (6) is preferably a compound represented by the following general formula (6-1).
Formula (6-1):

In the above general formula (6-1), R ⁶¹¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group. R ⁶¹¹ is preferably a substituted or unsubstituted aromatic group, and more preferably an unsubstituted aromatic group. ^R612 represents a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. R ⁶¹² is preferably a hydrogen atom or a substituted or unsubstituted aliphatic group, and more preferably a hydrogen atom. L ⁶¹¹ is —O—, —S—, —CO—, —NR ⁶¹³ — (R ⁶¹³ represents a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group), an alkylene group And a divalent linking group formed from one or more groups selected from an arylene group. The combination of the linking group is not particularly limited, but is preferably selected from —O—, —S—, —NR ⁶¹³ — and an alkylene group, and particularly preferably selected from —O—, —S— and an alkylene group. The linking group is preferably a linking group comprising two or more selected from -O-, -S- and an alkylene group.

Hereinafter, the substituted or unsubstituted aliphatic group will be described.
The aliphatic group may be linear, branched or cyclic, preferably having 1 to 25 carbon atoms, more preferably having 6 to 25 carbon atoms, particularly preferably having 6 to 20 carbon atoms. preferable. Specific examples of the aliphatic group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, t-butyl group, amyl group, isoamyl group, t- Amyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, bicyclooctyl group, adamantyl group, n-decyl group, t-octyl group, dodecyl group, hexadecyl group, octadecyl group, didecyl group, etc. Is mentioned.

The above aromatic group will be described below. The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, and more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include benzene, naphthalene, anthracene, biphenyl, terphenyl, and the like. As the aromatic hydrocarbon group, benzene, naphthalene, and biphenyl are particularly preferable. As the aromatic heterocyclic group, those containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom are preferable. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, Examples thereof include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene and the like. As the aromatic heterocyclic group, pyridine, triazine, and quinoline are particularly preferable.

  The substituent T has the same meaning as described in the general formula (3).

The general formula (6) is more preferably a compound represented by the following general formula (6-2).
General formula (6-2):

In the general formula (3), R ⁶²¹ , R ⁶²² , R ⁶²³ , R ⁶²⁴ , R ⁶²⁵ , R ⁶²⁶ , R ⁶²⁷ , R ⁶²⁸ , R ⁶²⁹ and R ⁶³⁰ each independently represent a hydrogen atom or a substituent, As the substituent, the above substituent T can be applied.

R ⁶²¹ , R ⁶²² , R ⁶²³ , R ⁶²⁴ , R ⁶²⁵ , R ⁶²⁶ , R ⁶²⁷ , R ⁶²⁸ , R ⁶²⁹ and R ⁶³⁰ are preferably alkyl groups, alkenyl groups, alkynyl groups, aryl groups, amino groups, alkoxy groups. Group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group , Sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group , Hydroxamic acid group, sulfino group, hydride A dino group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Is, for example, an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group, a morpholino group, a benzoxazolyl group, a benzimidazolyl group, a benzthiazolyl group, and the like, and more preferably an alkyl group. , Aryl group, aryloxycarbonylamino group, alkoxy group and aryloxy group, particularly preferably alkyl group, aryl group and aryloxycarbonylamino group. These substituents may be further substituted, and when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring. R ⁶²¹ and R ⁶²⁶ , R ⁶²² and R ⁶²⁷ , R ⁶²³ and R ⁶²⁸ , R ⁶²⁴ and R ⁶²⁹ , and R ⁶² d and R ⁶³⁰ are preferably the same. Further, R ^{621 to} R ⁶³⁰ are more preferably hydrogen atoms.

L ⁶²¹ is one or more selected from —O—, —S—, —CO—, —NR ⁶³¹ — (R ⁶³¹ represents a hydrogen atom, an aliphatic group or an aromatic group), an alkylene group, and an arylene group. Represents a divalent linking group formed from a group. The combination of the linking group is not particularly limited, but —O—, —S—, —
It is preferably selected from NR ⁶³¹ — and an alkylene group, particularly preferably selected from —O—, —S— and an alkylene group. The linking group is more preferably a linking group consisting of two or more selected from -O-, -S- and an alkylene group.

  Although the preferable example of a compound represented by General formula (6), General formula (6-1), or General formula (6-2) is shown below, this invention is not limited to these specific examples. .

Any of the compounds used in the present invention can be produced from known compounds.
The compound represented by any one or more of general formulas (6), (6-1), and (6-2) is generally obtained by a condensation reaction of a sulfonyl chloride and a polyfunctional amine.

  Of the compounds represented by the general formulas (1) to (6) that are retardation regulators used in the present invention, the compounds represented by the general formulas (1) to (3) are preferable, and the general formula (2) The compound represented by is most preferable.

  Moreover, as a retardation regulator used for this invention, the compound whose octanol-water partition coefficient (logP value) is 0-7 among the compounds of General formula (1)-(6) is preferable. If the logP value of the compound is 7 or less, the compatibility with the cellulose acylate is excellent, and problems such as white turbidity of the film and powder blowing do not occur. A log P value of 0 or more is preferred because the hydrophilicity becomes too high and problems such as deterioration of the water resistance of the cellulose acylate film do not occur. A more preferable range for the logP value is 1 to 6, and a particularly preferable range is 1.5 to 5.

The octanol-water partition coefficient (log P value) can be measured by a flask shaking method described in JIS Z-7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of actual measurement.
As a calculation method, the Crippen's fragmentation method {“J. Chem. Inf. Compute. Sci.”, 27, p. 21 (1987)}, Viswanadhan's fragmentation method {“J. Chem. Inf. Compute. Sci.”, 29, p. 163 (1989)}, Broto's fragmentation method {"Eur. J. Med. Chem.-Chim. Theor.", Vol. 19, p. 71 (1984)} is preferably used, and the Crippen's fragmentation method is more preferable. When the log P value of a certain compound varies depending on the measurement method or calculation method, whether or not the compound is within the above range is determined by the Crippen's fragmentation method.

  The compounds of the general formulas (1) to (6) preferably have a molecular weight of 150 or more and 3000 or less, preferably 170 or more and 2000 or less, and particularly preferably 200 or more and 1000 or less. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.

The compounds of the general formulas (1) to (6) are preferably liquid at 25 ° C. or a solid having a melting point of 25 to 250 ° C., more preferably liquid at 25 ° C. or a melting point of 25 to 25 ° C. 200 ° C
It is a solid. Moreover, it is preferable that the compound which lowers a retardation does not volatilize in the process of dope casting of cellulose acylate film production, and drying.

  The addition amount of the compounds of the general formulas (1) to (6) is preferably 0.01 to 30% by mass, more preferably 1 to 25% by mass, and more preferably 5 to 20% with respect to the cellulose acylate. It is particularly preferable that the content is mass%.

  The compounds represented by the general formulas (1) to (6) may be used alone, or two or more compounds may be mixed and used in an arbitrary ratio.

  The timing of adding the compounds of the general formulas (1) to (6) may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  In the compounds of the general formulas (1) to (6), the average content of the compound in the portion from the surface on at least one side to 10% of the total film thickness is the average of the compound in the center of the cellulose acylate film. The content is preferably 80 to 99%. The abundance of the compound used in the present invention can be determined, for example, by measuring the amount of the compound at the surface and the central part by a method using an infrared absorption spectrum described in JP-A-8-57879.

[Compound expressing hydrophobicity]
The compound expressing hydrophobicity used in the present invention is a compound having at least one hydrogen bond donating group and having an octanol / water partition coefficient (log P) of 1 or more and 8 or less. A compound having a hydrogen bond-donating group is advantageous and preferable in terms of the trade-off relationship between the effect of hydrophobizing the cellulose acylate film and the prevention of bleeding out. As the hydrogen bond donating group, a functional group such as —OH group and —NH group is particularly preferred. In addition, when log P is 8 or less, problems such as bleeding out do not occur, and when log P is 1 or more, the retention property in a cellulose acylate film of a compound that exhibits hydrophobicity is excellent. preferable.

  The molecular weight of the compound expressing hydrophobicity used in the present invention is preferably from 250 to 1,000. The boiling point is preferably 260 ° C. or higher. The boiling point can be measured using a commercially available measuring device, for example, “TG / DTA100” {manufactured by Seiko Electronics Co., Ltd.}.

  Various compounds can be used as the compound expressing hydrophobicity used in the present invention. Among the compounds represented by the general formula (7) and the general formulas (1) to (6), hydrogen bonding Compounds having a donating group and log P in the above range are preferred. Among the compounds represented by the general formulas (1) to (6), the compounds represented by the general formulas (4) to (6) are preferable as the compounds that exhibit hydrophobicity in the present invention.

Next, the compound of the general formula (7) will be described in detail.
General formula (7):

In the general formula (7), X ⁷¹ represents a boron atom, C—R ⁷¹ (R ⁷¹ represents a hydrogen atom or a substituent), a nitrogen atom, a phosphorus atom or P═O, and X ⁷¹ is preferably a boron atom, C—R ⁷¹ {Preferable as R ⁷¹ is aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino Group, aryloxycarbonylamino group, sulfonylamino group, hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group, more preferably aryl group, alkoxy group, aryl An oxy group, a hydroxy group, and a halogen atom, more preferably an alkoxy group A hydroxy group, particularly preferably a hydroxy group}, a nitrogen atom or P = O, more preferably a C-R ⁷¹ or a nitrogen atom, particularly preferably a C-R ^71.

R ⁷¹¹ , R ⁷¹² , R ⁷¹³ , R ⁷¹⁴ , R ⁷¹⁵ , R ⁷²¹ , R ⁷²² , R ⁷²³ , R ⁷²⁴ , R ⁷²⁵ , R ⁷³¹ , R ⁷³² , R ⁷³³ , R ⁷³⁴ , and R ⁷³⁵ are each independently Represents a hydrogen atom or a substituent, and the substituent T described above can be applied as the substituent. R ⁷¹¹ , R ⁷¹² , R ⁷¹³ , R ⁷¹⁴ , R ⁷¹⁵ , R ⁷²¹ , R ⁷²² , R ⁷²³ , R ⁷²⁴ , R ⁷²⁵ , R ⁷³¹ , R ⁷³² , R ⁷³³ , R ⁷³⁴ , and R ⁷³⁵ , preferably alkyl Group, alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryl Oxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom) , Bromine atom, iodine atom), cyano group, sulfo group, carboxy Group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12, and the hetero atom includes, for example, nitrogen atom, oxygen atom A sulfur atom, specifically imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), a silyl group, more preferably an alkyl group, an aryl group, A substituted or unsubstituted amino group, an alkoxy group, and an aryloxy group are preferable, and an alkyl group, an aryl group, and an alkoxy group are more preferable.

  These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Hereinafter, the compound represented by the general formula (7) will be described in detail with specific examples, but the present invention is not limited to the following specific examples.

  The above-mentioned compounds that exhibit hydrophobicity can be used alone or in combination of two or more.

  In the present invention, the compound exhibiting hydrophobicity is preferably used in an amount of 0.01 to 30 parts by mass, and more preferably 0.5 to 25 parts by mass with respect to 100 parts by mass of cellulose acylate. In the present invention, the method of adding a compound that exhibits hydrophobicity is dissolved in an organic solvent such as alcohol, methylene chloride, or dioxolane, and then added to the cellulose acylate solution (dope) or added directly into the dope composition. May be.

[Retardation of cellulose acylate film]
The retardation Re and Rth will be described in detail below.
In the present invention, Re _λ and Rth _λ respectively represent the retardation in the front direction and the retardation in the thickness direction at the wavelength λ.

[Measurement of retardation value]
A method for measuring the retardation of the cellulose acylate film of the present invention will be described.

(Retardation Re in the front direction, retardation Rth in the film thickness direction)
A cellulose acylate film sample 30 mm × 40 mm was conditioned at 25 ° C. and 60% RH for 2 hours, and Re _λ was a wavelength λ nm using an automatic birefringence meter “KOBRA 21ADH” (manufactured by Oji Scientific Instruments). The light was incident in the normal direction of the film and measured. Rth _λ is the Re _λ and the retardation value measured by making light of wavelength λ nm incident from the direction inclined + 40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis, Letters measured in a total of three directions, with the in-plane slow axis as the tilt axis and the retardation value measured by incidence of light of wavelength λ nm from the direction inclined by -40 ° with respect to the film normal direction Based on the foundation value, an assumed average refractive index value of 1.48 and a film thickness were input and calculated.

(Re and Rth fluctuations in the wavelength range from 400 nm to 700 nm)
A cellulose acylate film sample 30 mm × 40 mm was conditioned at 25 ° C. and 60% RH for 2 hours. Using an ellipsometer “M-150” (manufactured by JASCO Corporation), light with a wavelength of 700 nm to 400 nm was filmed. By making the light incident in the normal direction, the Re at each wavelength was determined, and the fluctuation due to the Re wavelength was measured. In addition, with respect to fluctuations due to the wavelength of Rth, light having a wavelength of 700 to 400 nm is incident from the direction inclined by + 40 ° with respect to the normal direction of the film with the Re and in-plane slow axis as the tilt axis. The measured retardation value and the retardation value measured by injecting light having a wavelength of 700 to 400 nm from the direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis. Based on the retardation values measured in a total of three directions, it was calculated by inputting the assumed average refractive index of 1.48 and the film thickness.

In the present invention, as the cellulose acylate film having a small optical anisotropy (Re, Rth), the retardation Re in the front direction and the retardation Rth in the film thickness direction at a wavelength of 630 nm are respectively in the range of the following formula (1). It is preferable to satisfy.
Formula (1): −25 nm ≦ Rth ₆₃₀ ≦ 25 nm and 0 nm ≦ Re ₆₃₀ ≦ 10 nm.
More preferably, the retardation Rth satisfies the range of the following formula (1-1), and particularly preferably satisfies the range of the following formula (1-2).
Formula (1-1): −20 nm ≦ Rth ₆₃₀ ≦ 20 nm and 0 nm ≦ Re ₆₃₀ ≦ 5 nm,
Formula (1-2): −15 nm ≦ Rth ₆₃₀ ≦ 15 nm and nm ≦ Re ₆₃₀ ≦ 2 nm.

  In the cellulose acylate film of the present invention, in the wavelength range of 400 nm to 700 nm, the Rth variation is preferably 25 nm or less, the Re variation is preferably 10 nm or less, the Rth variation is 20 nm or less, and the Re Is more preferably 5 nm or less, particularly preferably Rth is 15 nm or less and Re is 3 nm or less.

Furthermore, in the cellulose acylate film of the present invention, the retardation Re in the front direction and the retardation Rth in the film thickness direction at a wavelength of 630 nm preferably satisfy the relationship of the following formula (2). It is more preferable to satisfy the relationship, and it is further preferable to satisfy the relationship of the mathematical formula (2-2).
Formula (2): | Re ₆₃₀ × Rth ₆₃₀ | ≦ 200,
Formula (2-1): | Re ₆₃₀ × Rth ₆₃₀ | ≦ 100,
Formula (2-2): | Re ₆₃₀ × Rth ₆₃₀ | ≦ 50.

Moreover, when the retardation Re of the front direction in wavelength 630nm of the cellulose acylate film of this invention is a value of 1 or more, it is preferable to satisfy | fill the relationship of retardation Rth of a film thickness direction, and following Numerical formula (3).
Equation _{(3): 0.5 ≦ Rth 630} / Re 630 ≦ 5.0.

More preferably, it is more preferable to satisfy | fill the relationship of the said Numerical formula (2) and Numerical formula (3) simultaneously. That is,
| Re ₆₃₀ × Rth ₆₃₀ | ≦ 200 and 0.5 ≦ Rth ₆₃₀ / Re ₆₃₀ ≦ 5.0.

(Wavelength dispersion adjusting agent)
In the present invention, it is possible to preferably use a compound (hereinafter also referred to as a wavelength dispersion adjusting agent) that lowers the variation in retardation of the cellulose acylate film in the wavelength range of 400 nm to 700 nm, that is, wavelength dispersion. Hereinafter, the wavelength dispersion adjusting agent will be described.

The above-described wavelength dispersion adjusting agent has absorption in the ultraviolet region of 200 to 400 nm, and exhibits wavelength dispersion in the wavelength range of 400 nm to 700 nm of the film, that is, | Re ₄₀₀ −Re ₇₀₀ | and | Rth ₄₀₀ −Rth ₇₀₀ | It is preferable to contain 0.01-30 mass% of at least 1 type of the compound to reduce, with respect to cellulose acylate solid content.

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

  Therefore, by using the above-described compound having absorption in the ultraviolet region of 200 to 400 nm and having the wavelength dispersion of Re and Rth of the compound itself large on the short wavelength side, Re and Rth of the cellulose acylate film are used. Can be prepared. For this purpose, the compound for adjusting the wavelength dispersion is required to be sufficiently uniformly compatible with the cellulose acylate. The absorption band range in the ultraviolet region of such a compound is preferably 200 to 400 nm, more preferably 220 to 395 nm, and further preferably 240 to 390 nm. Furthermore, it is preferable to have at least one absorption maximum in a wavelength range of 250 nm or more and 360 nm or less, and it is more preferable to have at least one absorption maximum in a wavelength range of 300 nm to 360 nm.

  Specific structures of the wavelength dispersion adjusting agent preferably used in the present invention include, for example, a benzotriazole compound, a triazine compound, a benzophenone compound, a compound containing a cyano group, a compound containing a sulfo group, an oxybenzophenone compound, and a salicylic acid ester type. Examples include compounds and nickel complex salts, but the present invention is not limited to these compounds.

  From the viewpoint of volatility, the wavelength dispersion regulator preferably used in the present invention as described above preferably has a molecular weight of 250 to 1,000. More preferably, it is 260-800, More preferably, it is 270-800, Most preferably, it is 300-800. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.

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

(Addition amount of wavelength dispersion adjusting agent)
The addition amount of the wavelength dispersion adjusting agent preferably used in the present invention is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass of cellulose acylate. It is especially preferable that it is 2-10 mass%.

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

  In the present invention, the average log P of all low molecular weight compounds having a molecular weight of 1000 or less, such as a retardation modifier, a hydrophobic compound and a wavelength dispersion modifier, which are added to cellulose acylate in the present invention is preferably 2 or more and 7 or less. 5 to 6 is more preferable, and 3 to 5 is most preferable. If the average log P is not too small, the retention of the low molecular weight compound will not be a problem, and if it is not too large, the adjustment of chromatic dispersion will not be insufficient.

The average logP can be defined by the following mathematical formula (6).
Formula (6): Average log P = Σ (m _i × log P _i )
Here, m _i represents the mass fraction of the i-th low molecular compound with respect to the total amount of low molecular compound added, and log P _i represents the log P of the i-th low molecular compound.

  In the present invention, as the logP value, a value calculated based on the retention time of a liquid chromatograph, and a value calculated by a commercially available calculation program can be used in addition to the actual measured value of the partition ratio between water / butanol.

[Cellulose acylate]
[Cellulose acylate raw material cotton]
Cellulose acylate raw material cellulose used in the present invention includes cotton linter and wood pulp (hardwood pulp, softwood pulp) and the like, and any cellulose acylate obtained from any raw material cellulose can be used, optionally mixed. May be. Detailed descriptions of these raw material celluloses can be found in, for example, “Plastic Materials Course (17) Fibrous Resin” (Marusawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Publication Technical Report 2001-1745 ( 7 to 8) can be used, and the cellulose acylate film of the present invention is not particularly limited.

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

  As described above, in the cellulose acylate, the substitution degree of the hydroxyl group of cellulose is not particularly limited, but the acyl substitution degree of the cellulose hydroxyl group is preferably 2.50 to 3.00. Furthermore, the substitution degree is preferably 2.75 to 3.00, and more preferably 2.85 to 3.00.

  Among the acetic acid substituted for the hydroxyl group of cellulose and / or the fatty acid having 3 to 22 carbon atoms, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an allyl group, and is not particularly limited. A mixture of They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, or aromatic alkyl carbonyl esters of cellulose, 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, i-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. The most preferred group is acetyl.

Among the acyl substituents substituted on the hydroxyl group of the cellulose, when it is substantially composed of at least two kinds of acetyl group / propionyl group / butanoyl group, the total substitution degree is 2.50 to 3.00 In addition, the optical anisotropy of the cellulose acylate film can be more suitably reduced. The degree of acyl substitution is more preferably 2.60 to 3.00, still more preferably 2.65 to 3.00.
In the case where the acyl substituent of the cellulose acylate is substantially composed of only an acetyl group, the optical anisotropy of the cellulose acylate film is more enhanced when the total degree of substitution is 2.50 to 2.95. It can reduce suitably.

[Degree of polymerization of cellulose acylate]
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. . If the degree of polymerization is not more than the upper limit, the viscosity of the cellulose acylate dope solution does not become too high, and a film can be easily produced by casting. If the degree of polymerization is equal to or greater than the lower limit, it is preferable because there is no inconvenience such as a decrease in strength of the produced film. The average degree of polymerization can be measured by the intrinsic viscosity method of Uda et al. {Kazuo Uda, Hideo Saito, "Journal of Textile Society," Vol. 18, No. 1, pages 105-120 (1962)}. This method is also described in detail in JP-A-9-95538.

  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 a mass average molecular weight, Mn is a number average molecular weight) is small, and the molecular weight A narrow distribution is preferred. The specific value of Mw / Mn is preferably 1.0 to 3.0, more preferably 1.0 to 2.0, and most preferably 1.0 to 1.6. preferable.

  Further, when the low molecular component of cellulose acylate is removed, the average molecular weight (degree of polymerization) increases, but the viscosity is lower than that of normal cellulose acylate, which is useful. Cellulose acylate having a small amount of low molecular components can be obtained by removing low molecular components from cellulose acylate synthesized by a usual method. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent.

In addition, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose. When the amount of the sulfuric acid catalyst is within the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized.

  When used in the production of 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, particularly 0.7%. It is a cellulose acylate having a water content of not more than mass%. In general, cellulose acylate contains water, and a water content of about 2.5 to 5% by mass is known. In order to obtain a preferable moisture content of the cellulose acylate in the present invention, it is necessary to dry the cellulose acylate, and the method is not particularly limited as long as the desired moisture content is obtained. These cellulose acylates are described in detail on pages 7 to 12 of the raw material cotton and the synthesis method in the Japan Society for Invention and Technology (public technical number 2001-1745, published on March 15, 2001, Japan Society for Invention). ing.

  In the present invention, the cellulose acylate may be used by mixing two or more different types of cellulose acylates within the above ranges such as a substituent, a substitution degree, a polymerization degree, and a molecular weight distribution.

[Additives to cellulose acylate]
In the cellulose acylate solution used in the present invention, in each preparation step, in addition to the retardation adjusting agent, the compound expressing hydrophobicity and the wavelength dispersion adjusting agent, various additives (for example, for example, UV absorbers, plasticizers, deterioration inhibitors, fine particles, etc.) can be added, and these will be described below. Further, the addition may be performed at any time in the dope preparation step, but may be performed by adding an additive to the final preparation step of the dope preparation step.

[Matting agent fine particles]
The cellulose acylate film of the present invention preferably contains fine particles as a matting agent. The fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and Mention may be made of calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / L 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 / L, more preferably 100 to 200 g / L. A higher apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are reduced.

  These fine particles usually form secondary particles having an average particle size of 0.1 to 3.0 μm, and exist as aggregates of primary particles in the film, and 0.1 to 3 on the film surface. An unevenness of 0.0 μm is formed. The secondary average particle size is preferably from 0.2 μm to 1.5 μm, more preferably from 0.4 μm to 1.2 μm, and most preferably from 0.6 μm to 1.1 μm. The primary and secondary particle sizes were determined by observing the particles in the film with a scanning electron microscope and determining the diameter of a circle circumscribing the particles as the particle size. In addition, 200 particles were observed at different locations, and the average value was taken as the average particle size.

The fine particles of silicon dioxide are, for example, “Aerosil R972”, “Aerosil R972V”, “Aerosil R974”, “Aerosil R812”, “Aerosil 200”, “Aerosil 200V”, “Aerosil 300”, “Aerosil R202”, “Aerosil”. Commercial products such as “OX50” and “Aerosil TT600” {manufactured by Nippon Aerosil Co., Ltd.} can be used. Zirconium oxide fine particles are commercially available, for example, under the trade names of “Aerosil R976” and “Aerosil R811” {manufactured by Nippon Aerosil Co., Ltd.}
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 / L or more, and the optical film has low turbidity. This is particularly preferable because the effect of reducing the coefficient of friction is large while maintaining it.

In the present invention, in order to obtain a cellulose acylate film having particles having a small secondary average particle size, several methods are conceivable when preparing a fine particle dispersion. For example, 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 cellulose acylate solution, dissolved by stirring, and further mixed with the main cellulose acylate dope solution. There is a way. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are more difficult to reaggregate. In addition, after adding a small amount of cellulose ester to the solvent and dissolving with stirring, fine particles are added to this and dispersed with a disperser. This is used as a fine particle additive solution, and this fine particle additive solution is sufficiently mixed with the dope solution using an in-line mixer. There is also a method of mixing. Although the present invention is not limited to these methods, 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. Most preferred is 20% by weight. 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 cellulose acylate dope solution is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and 0.08 to 0.16 g per 1 m ^2. Most preferred.

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

[Plasticizer, degradation inhibitor, release agent]
In the cellulose acylate film of the present invention, in addition to the above-mentioned retardation adjusting agent, compound that exhibits hydrophobicity, wavelength dispersion adjusting agent, and the like, various additives (for example, plasticizers) according to applications in each preparation step. Agents, degradation inhibitors, release agents, infrared absorbers, etc.), which may be solid or oily.
That is, the melting point and boiling point are not particularly limited. For example, mixing of an ultraviolet absorber at 20 ° C. or lower and 20 ° C. or higher, and similarly, mixing of a plasticizer is described in, for example, Japanese Patent Application Laid-Open No. 2001-151901. Moreover, as an infrared absorber, what was described, for example in Unexamined-Japanese-Patent No. 2001-194522 can be used. Further, the amount of each material added is not particularly limited as long as the function is exhibited. Furthermore, when the cellulose acylate film is formed from multiple layers, the type and amount of additives in each layer may be different, and are described in, for example, Japanese Patent Application Laid-Open No. 2001-151902. This is a known technique. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

[Ratio of each compound addition]
In the cellulose acylate film of the present invention, the total amount of compounds having a molecular weight of 3000 or less is desirably 5 to 45% by mass with respect to the mass of cellulose acylate. More preferably, it is 10-40 mass%, More desirably, it is 15-30 mass%. As described above, these compounds include retardation regulators, compounds that exhibit hydrophobicity, wavelength dispersion regulators, UV absorbers, UV inhibitors, plasticizers, deterioration inhibitors, fine particles, release agents, infrared rays. The molecular weight is preferably 3000 or less, more preferably 2000 or less, and even more preferably 1000 or less. If the total amount of these compounds is equal to or greater than the lower limit value, the properties of the cellulose acylate alone will not be excessive. For example, the optical performance and physical strength are likely to fluctuate due to changes in temperature and humidity. Does not occur. Also, if the total amount of these compounds is less than or equal to the upper limit, problems such as exceeding the limit of compatibility of the compounds in the cellulose acylate film and depositing on the film surface to cause the film to become cloudy (crying out of the film) Therefore, these compounds are preferably used within the above range as a total amount. Furthermore, the addition timing may be added at any time in the dope preparation step, but as a final step of the dope preparation step, a step of adding an additive may be performed.

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

  As described above, for the cellulose acylate film of the present invention, a chlorinated halogenated hydrocarbon may be used as a main solvent, and as described in JIII Journal of Technical Disclosure 2001-1745 (pages 12 to 16). In addition, a non-chlorine solvent may be used as the main solvent, and is not particularly limited. In the present invention, the cellulose acylate may be a poor solvent of cellulose acylate in addition to the main solvent. The poor solvent may be used in an amount of 5 to 50% by mass with respect to the main solvent, and more preferably 5 to 30% by mass. Examples of the poor solvent include methanol, ethanol, butanol and the like.

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

[Manufacturing process of cellulose acylate film]
[Dissolution process]
In preparing the cellulose acylate solution (dope) in the present invention, the dissolution method is not particularly limited, and dissolution at room temperature may be used, cooling dissolution method or high temperature dissolution method may be used, and a combination thereof may be performed. . Regarding the preparation of the cellulose acylate solution in the present invention, as well as the solution concentration and filtration steps involved in the dissolution step, the Japan Institute of Technology published technical report (
The manufacturing process described in detail on pages 22 to 25 in the public technical number 2001-1745, published on March 15, 2001, Japan Institute of Invention) is preferably used.

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

[Casting, drying, winding process]
Next, the manufacturing method of the film using the cellulose acylate solution (dope) in this invention is described. For the method and equipment for producing the cellulose acylate film of the present invention, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film are used. The dope (cellulose acylate solution) prepared in the dissolving machine (kettle) is temporarily stored in the storage kettle, and the foam contained in the dope is defoamed to make the final adjustment. The dope is sent from the dope discharge port to the pressurizing die through a pressurizing quantitative gear pump capable of feeding the dope with high accuracy by the number of revolutions, and then the dope is run endlessly from the die (slit) of the pressurizing die. The dope film (also referred to as a web) is peeled off from the metal support at the peeling point where the metal support is almost cast around the metal support. The obtained web is sandwiched between clips and conveyed by a tenter while holding the width to be dried, and then the obtained film is mechanically conveyed by a roll group of a drying device to finish drying, and a winder And roll up to a predetermined length in a roll. The combination of the tenter and the roll group dryer varies depending on the purpose. In a solution casting film forming method used for a functional protective film or a silver halide photographic light-sensitive material as an optical member for an electronic display as a main application of the cellulose acylate film of the present invention, a solution casting film forming apparatus is used. In addition, a coating apparatus is often added for surface processing on films such as an undercoat layer, an antistatic layer, an antihalation layer, and a protective layer. These are described in detail on pages 25 to 30 in the Japan Society for Invention and Innovation Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society for Invention), and include casting (including co-casting). ), Metal support, drying, peeling, etc., and can be preferably used in the present invention.

The residual solvent content at any point on the casting film-forming step of the cellulose acylate film of the present invention is defined by the following mathematical formula (7).
Formula (7): (W _t −W ₀ ) × 100 / W ₀
W _t : Measurement mass of the actually measured dope film.
W ₀ : film mass when dried at 110 ° C. for 3 hours after completion of drying.
The residual solvent content at the peeling point is preferably in the range of 5 to 90% by mass, and the content of the poor solvent in the residual solvent is preferably in the range of 10 to 95% by mass.

[Stretching]
The cellulose acylate film of the present invention may be stretched, and the stretching can be either uniaxial stretching or biaxial stretching. 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, it is stretched in the longitudinal direction. Or after extending | stretching to a longitudinal direction, you may extend | stretch to the width direction.

Examples of the method of stretching in the width direction include, for example, JP-A-62-115035 and JP-A-4-1521.
No. 25, No. 4-284221, No. 4-298310, No. 11-48271, and the like. The film is stretched at room temperature or under heating conditions. The heating temperature is preferably not higher than the glass transition temperature of the film. The film can be stretched during drying, and is particularly effective when the solvent remains.

  In the case of stretching in the longitudinal direction, for example, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film peeling speed. In the case of stretching in the width direction, the film can also be stretched by conveying while holding the width of the film with a tenter and gradually widening the width of the tenter. After the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine).

  The stretch ratio of the cellulose acylate film of the present invention in the transport direction (longitudinal direction) (the ratio of the increase due to stretching relative to the original length) is preferably in the range of 1 to 100%, and is preferably 1 to 50%. More preferably, it is in the range, and most preferably in the range of 1 to 35%. The draw ratio in the direction perpendicular to the transport direction (width direction) is preferably 1 to 100%, more preferably 5 to 50%, and more preferably 10 to 40%. Most preferred.

[Film thickness]
10-120 micrometers is preferable, as for the thickness of the cellulose acylate film of this invention, 20-100 micrometers is more preferable, and 30-90 micrometers is more preferable. Moreover, the difference between the maximum value and the minimum value of the 1 m square film of the cellulose acylate film of the present invention, which is arbitrarily cut, is preferably 10% or less with respect to the average value of the thickness, and is 5% or less. It is more preferable that

[Physical evaluation of cellulose acylate film]
[Optical performance]
(Change in optical performance of film after high humidity treatment)
Regarding the change in optical performance of the cellulose acylate film of the present invention due to environmental changes, the amount of change in Re and Rth of a film treated at 60 ° C. and 90% RH for 240 hours is preferably 15 nm or less. More preferably, it is 12 nm or less, and further preferably 10 nm or less.

(Change in optical performance of film after high temperature treatment)
Further, the amount of change in Re and Rth of the film treated at 80 ° C. for 240 hours is preferably 15 nm or less. More preferably, it is 12 nm or less, and further preferably 10 nm or less.

(Humidity dependence of film Re and Rth)
The retardation Rth in the film thickness direction of the cellulose acylate film of the present invention preferably has a small change due to humidity. Specifically, the difference ΔRth between the Rth value at 25 ° C. and 10% RH represented by the following formula (8) and the Rth value at 25 ° C. and 80% RH is preferably 0 to 50 nm. More preferably, it is 0-40 nm, More preferably, it is 0-35 nm.
Formula (8): ΔRth = Rth _{10% RH} −Rth _{80% RH}

(Front retardation change before and after stretching)
Prepare a 100 x 100 mm cellulose acylate film sample and stretch it in the machine transport direction (MD direction) or in the direction perpendicular to the transport direction (TD direction) using a fixed uniaxial stretching machine at a temperature of 140 ° C. Went. Front retardation of each sample before and after stretching (R
e) was measured using an automatic birefringence meter “KOBRA 21ADH” (manufactured by Oji Scientific Instruments). The detection of the slow axis was determined from the orientation angle obtained during the retardation measurement.
It is preferable that the change in Re by stretching is small. Specifically, the front direction retardation (nm) of a film in which Re _(n) is stretched by n (%), and the front direction letter of a film in which Re ₍₀₎ is not stretched. It is preferable to satisfy the relationship of the following mathematical formula (5), and it is more preferable to satisfy the relationship of the following mathematical formula (5-1).
Formula (5): | Re _(n) −Re ₍₀₎ | /n≦1.0,
Formula (5-1): | Re _(n) −Re ₍₀₎ | /n≦0.3.

(In-plane variation of retardation of cellulose acylate film)
In the cellulose acylate film of the present invention, the values of Re and Rth at a wavelength of 630 nm preferably satisfy the relationship of the following formula (4), and more preferably satisfy the relationship of the following formula (4-1).
Formula (4): | Re _{630 (max)} −Re _{630 (min)} | ≦ 5 and | Rth _{630 (max)} −Rth _{630 (min)} | ≦ 10
Formula (4-1): | Re _{630 (max)} −Re _{630 (min)} | ≦ 3 and | Rth _{630 (max)} −Rth _{630 (min)} | ≦ 5
{In the formula, Re _{630 (max)} and Rth _{630 (max)} are the maximum retardation values at a wavelength of 630 nm of an arbitrarily cut out 1 m square film, and Re _{630 (min)} and Rth _{630 (min)} are the minimum at a wavelength of 630 nm. It is a retardation value. }

(Photoelastic coefficient)
The photoelastic coefficient of the cellulose acylate film of the present invention is preferably 50 × 10 ⁻¹³ cm ² / dyne or less. It is more preferably 30 × 10 ⁻¹³ cm ² / dyne or less, and further preferably 20 × 10 ⁻¹³ cm ² / dyne or less. As a specific measuring method, a tensile stress is applied to the major axis direction of a 12 mm × 120 mm cellulose acylate film sample, and the retardation at that time is measured with an ellipsometer “M150” (manufactured by JASCO Corporation). The photoelastic coefficient was calculated from the amount of change in retardation with respect to stress.

(Haze of film)
The haze of the cellulose acylate film of the present invention is preferably 0.01 to 2.0%. More preferably, it is 0.05 to 1.5%, and further preferably 0.1 to 1.0%. As an optical film, the transparency of the film is important. The haze was measured according to JIS K-6714 using a cellulose acylate film sample 40 mm × 80 mm of the present invention at 25 ° C. and 60% RH using a haze meter “HGM-2DP” (manufactured by Suga Test Instruments Co., Ltd.). .

(Spectral characteristics, spectral transmittance)
A transmittance of a cellulose acylate film sample 13 mm × 40 mm at a wavelength of 300 to 450 nm was measured with a spectrophotometer “U-3210” {Hitachi, Ltd.} at 25 ° C. and 60% RH. The inclination width was obtained at a wavelength of 72% -5%. The limit wavelength was expressed by a wavelength of (gradient width / 2) + 5%. The absorption edge is represented by a wavelength having a transmittance of 0.4%. From this, the transmittance | permeability of 380 nm and 350 nm was evaluated.
In the cellulose acylate film of the present invention, the spectral transmittance at a wavelength of 380 nm is preferably 45% or more and 95% or less, and the spectral transmittance at a wavelength of 350 nm is preferably 10% or less.

[Physical properties]
(Glass glass transition temperature Tg)
The glass transition temperature (Tg) of the cellulose acylate film of the present invention is preferably 80 to 165 ° C. From the viewpoint of heat resistance, Tg is more preferably 100 to 160 ° C, and particularly preferably 110 to 150 ° C. The measurement of the glass transition temperature Tg was carried out using a differential scanning calorimeter “DSC2910” (manufactured by T.A. Instruments Co., Ltd.) with a cellulose acylate film sample of 10 mg of the present invention at a temperature rising / falling rate of 5 ° C./min. Then, calorimetry was performed to calculate the glass transition temperature Tg.

(Equilibrium moisture content of film)
The equilibrium moisture content of the cellulose acylate film of the present invention is 25 ° C., regardless of the film thickness, so as not to impair the adhesion with a water-soluble polymer such as polyvinyl alcohol when used as a protective film of a polarizing plate. The equilibrium moisture content at 80% RH is preferably 0 to 4%. It is more preferably 0 to 3.2%, further preferably 0.1 to 3.2%, and particularly preferably 1 to 3%. If the equilibrium moisture content is 4.0% or less, it is preferable that the dependency of retardation due to humidity change does not become too large when used as a support for an optical compensation film. If the equilibrium water content is 3.2% or less, it is more preferable that the humidity change of the retardation is small.
The water content was measured by using a cellulose acylate film sample of 7 mm × 35 mm according to the present invention with a moisture meter, a sample drying apparatus “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation) and Karl Fischer. Measured by the method. The moisture content (g) was calculated by dividing by the sample mass (g).

(Water permeability of film)
The moisture permeability of the film is determined by measuring the film under conditions of 60 ° C. and 95% RH based on JIS Z-0208 and converting it to a film thickness of 80 μm.
The moisture permeability decreases as the thickness of the cellulose acylate film increases, and increases as the thickness decreases. Therefore, it is necessary to convert the sample of any film thickness to a standard of 80 μm. The film thickness can be converted according to the following mathematical formula (9).
Formula (9): Moisture permeability in terms of 80 μm = measured moisture permeability × measured film thickness (μm) / 80 (μm).

The measurement method of water vapor transmission rate is “Polymer Physical Properties II” (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294 “Measurement of vapor permeation amount (mass method, thermometer method, vapor pressure method, adsorption amount method) Can be applied.
Specifically, a 70 mmφ cellulose acylate film sample of the present invention was conditioned at 25 ° C., 90% RH, 60 ° C., and 95% RH for 24 hours, respectively, and a moisture permeability test apparatus “KK-709007” {Toyo Seiki ( Co., Ltd.}, the water content per unit area was calculated (g / m ² ) according to JIS Z-0208, and determined according to the following formula (10).
Formula (10): Moisture permeability = mass after humidity control-mass before humidity control

The moisture permeability of the cellulose acylate film of the present invention is preferably 400 to 2000 g / m ² · 24 h. More preferably 500~1600g / m ² · 24h, and particularly preferably 600~1200g / m ² · 24h. If the moisture permeability is within 2000 g / m ² · 24 h, there will be no inconvenience such as the absolute value of the humidity dependence of the Re value and Rth value of the film exceeding 0.5 nm /% RH. An optical compensation film obtained by laminating an optically anisotropic layer on the cellulose acylate film is also preferable because the absolute value of the humidity dependence of the Re value and Rth value does not exceed 0.5 nm /% RH. Furthermore, it is preferable that an optical compensation sheet or a polarizing plate produced using such a film is incorporated in a liquid crystal display device because it does not cause a change in color or a decrease in viewing angle. On the other hand, when the moisture permeability of the cellulose acylate film is 400 g / m ² · 24 h or more, the cellulose acylate film prevents drying of the adhesive when the polarizer is attached to both sides of the polarizing film. This is preferable because it exhibits excellent adhesion.

(Dimensional change of film)
The dimensional stability of the cellulose acylate film of the present invention is as follows: dimensional change rate after standing for 24 hours under conditions of 60 ° C. and 90% RH (high humidity), and conditions of 90 ° C. and 5% RH It is preferable that the dimensional change rate after standing for 24 hours (high temperature) is 0.5% or less. More preferably, it is 0.3% or less, More preferably, it is 0.15% or less.

As a specific measurement method, two cellulose acylate film samples 30 mm × 120 mm were prepared, conditioned at 25 ° C. and 60% RH for 24 hours, and both ends with an automatic pin gauge {manufactured by Shinto Kagaku Co., Ltd.}. 6 mmφ holes were drilled at 100 mm intervals to obtain the original punch spacing (L ₀ ). After one sample was treated at 60 ° C. and 90% RH for 24 hours, the dimension of the punch interval (L ₁ ) was measured, and the other sample was treated at 90 ° C. and 5% RH for 24 hours. The dimension (L ₂ ) of the punch interval was measured. In all the measurement of the interval, measurement was made to the minimum scale 1/1000 mm, and the dimensional change rate was obtained according to the following formulas (11) and (12).
Formula (11): Dimensional change rate of 60 ° C. and 90% RH (high humidity) = {| L ₀ −L ₁ | / L ₀ } × 100,
Formula (12): Dimensional change rate of 90 ° C., 5% RH (high temperature) = {| L ₀ −L ₂ | / L ₀ } × 100.

(Elastic modulus of film)
Elastic modulus of the cellulose acylate film of this invention is preferably from 200 to 500 kgf / mm ^2, more preferably 240~470kgf / mm ^2, further preferably 270~440kgf / mm ^2. As a specific measurement method, using a universal tensile tester “STM T50BP” manufactured by Toyo Baldwin Co., Ltd., the stress at 0.5% elongation was measured at 23 ° C. and 70 RH% atmosphere at a tensile rate of 10% / min. The elastic modulus was determined.

[Film surface properties]
The surface of the cellulose acylate film of the present invention has an arithmetic average roughness (Ra) of surface irregularities based on JIS B-0601-1994 of 0.1 μm or less and a maximum height (Ry) of 0.5 μm or less. preferable. Preferably, the arithmetic average roughness (Ra) is 0.05 μm or less, and the maximum height (Ry) is 0.2 μm or less. The concave and convex shapes on the film surface can be evaluated by an atomic force microscope (AFM).

[Compound retention of film]
In the cellulose acylate film of the present invention, retentivity of various compounds such as a retardation adjusting agent and an ultraviolet absorber added to the film is required.

(Compound volatilization after film heat treatment)
Compounds added to the cellulose acylate film of the present invention, such as a retardation modifier, a hydrophobic compound, and a wavelength dispersion modifier, have a volatilization amount of 30 mass from a film treated at 80 ° C. for 240 hours. % Or less is preferable. More preferably, it is 25 mass% or less, and it is further more preferable that it is 20 mass% or less.
Note that the volatilization amount of the compound from the film was determined by immersing the film treated at 80 ° C. for 240 hours and the untreated film in a solvent, and analyzing the solvent after immersion by liquid high performance chromatography. Was calculated by the following mathematical formula (13) as the amount of the compound remaining in the film.
Formula (13): Volatilization amount (%) = {(Amount of residual compound in untreated product) − (Amount of residual compound in treated product)} / (Amount of residual compound in untreated product) × 100.

(Compound retention after film high temperature and high humidity treatment)
Retardation modifiers, compounds exhibiting hydrophobicity, and films such as wavelength dispersion modifiers added to the cellulose acylate film of the present invention are retained after high-temperature and high-humidity treatment. It is preferable that the mass change of the film when the cellulose acylate film is allowed to stand for 48 hours under the conditions of 80 ° C. and 90% RH is 0 to 5% by mass. More preferably, it is 0-3 mass%, More preferably, it is 0-2%.

(Method for evaluating holdability)
A cellulose acylate film sample was cut to a size of 10 cm × 10 cm, and the mass after being left for 24 hours in an atmosphere of 23 ° C. and 55% RH was measured. Then, the conditions were 80 ± 5 ° C. and 90 ± 10% RH. And left for 48 hours. The surface of the sample after the treatment was lightly wiped, the mass after standing for 1 day at 23 ° C. and 55% RH was measured, and the retention of the compound after the high temperature and high humidity treatment was calculated according to the following formula (14).
Formula (14): Compound retention after high-temperature and high-humidity treatment (mass%) = {(mass before standing−mass after standing) / mass before standing} × 100

[Mechanical properties of film]
(curl)
The curl value in the width direction of the cellulose acylate film of the present invention is preferably −10 / m to + 10 / m.
In the cellulose acylate film of the present invention, the surface treatment described later, when applying an optically anisotropic layer, the rubbing treatment, the alignment film, the coating and bonding of the optically anisotropic layer, etc. are long. When performing, if the curl value in the width direction of the film is within the above range, the handling of the film is hindered and the film is not cut off. In addition, the film comes into strong contact with the transport roll at the edge or center of the film and generates dust, resulting in more foreign matter adhering to the film and the frequency of point defects and coating streaks on the optical compensation film exceeding the allowable value. Such a problem does not occur. Further, by setting the curl in the above range, it is possible to reduce color spot failures that are likely to occur when an optically anisotropic layer is installed, and it is also preferable because bubbles can be prevented from entering when a polarizing film is bonded.

  The curl value can be measured according to a measurement method (ANSI / ASCPH1.29-1985) defined by the American National Standards Institute.

(Tear strength)
The tear strength of the film is measured by a method (Elmendorf tear method) based on the tear test method of JIS K-7128-2: 1998. The tear strength of the cellulose acylate film of the present invention is preferably 2 g or more in a thickness range of 20 to 80 μm. More preferably, it is 5-25g, Furthermore, it is 6-25g. Moreover, it is preferable that it is 8 g or more in 60 micrometers conversion, More preferably, it is 8-15 g. Specifically, the cellulose acylate film sample piece 50 mm × 64 mm can be measured for 2 hours under conditions of 25 ° C. and 65% RH, and then measured using a light load tear strength tester.

[Residual solvent amount of film]
The cellulose acylate film of the present invention is preferably dried under the conditions that the residual solvent amount relative to the film is in the range of 0.01 to 1.5% by mass. More preferably, it is 0.01-1.0 mass%. When the cellulose acylate film of the present invention is used as a transparent support such as an antireflection film or an optical compensation film, curling can be suppressed by setting the residual solvent amount to 1.5% or less. More preferably, it is 1.0 mass% or less. This is presumably because free deposition becomes smaller by reducing the amount of residual solvent during film formation by the casting method (solvent cast method) using the dope described above.

[Hygroscopic expansion coefficient of film]
The hygroscopic expansion coefficient of the cellulose acylate film of the present invention is preferably 30 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is more preferably 15 × 10 ⁻⁵ /% RH or less, and further preferably 10 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is preferably small, but usually it is 1.0 × 10 ⁻⁵ /% RH or more. The hygroscopic expansion coefficient indicates the amount of change in the length of the sample when the relative humidity is changed at a constant temperature. By adjusting this hygroscopic expansion coefficient, when the cellulose acylate film of the present invention is used as an optical compensation film support, the optical transmittance of the frame-shaped transmittance is increased while maintaining the optical compensation function of the optical compensation film. Leakage can be prevented.
(Measurement of hygroscopic expansion coefficient)
A sample having a width of 5 mm and a length of 20 mm was cut out from the produced cellulose acylate film, and one end was fixed and suspended in an atmosphere of 25 ° C. and 20% RH. A weight of 0.5 g was hung from the other end and left standing for a certain period of time. Next, the amount of deformation of the length was measured while maintaining a constant temperature and a humidity of 80% RH. The measurement was performed 10 samples for the same sample, and the average value was adopted.

[surface treatment]
The cellulose acylate film can achieve improved adhesion between the cellulose acylate film and each functional layer (for example, the undercoat layer and the back layer) by optionally performing a surface treatment. For the surface treatment of the cellulose acylate film, for example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used.

The glow discharge treatment here may be low-temperature plasma that occurs in a low-pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail on pages 30 to 32 in the Japan Society for Invention and Innovation Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention), and are preferably used in the present invention. be able to.

(Saponification treatment)
One effective means of surface treatment when the cellulose acylate film of the present invention is used as a transparent protective film of a polarizing plate is an alkali saponification treatment.

Hereinafter, the alkali saponification treatment will be specifically described.
The alkali saponification treatment of the cellulose acylate film is preferably performed in a cycle in which the film surface is immersed in an alkali solution, neutralized with an acidic solution, washed with water and dried. Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution, and the concentration of hydroxide ions is preferably in the range of 0.1 to 5.0 mol / L, and preferably 0.5 to 4.0 mol / L. More preferably, it is in the range. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably in the range of 40 to 70 ° C.

In the saponification treatment, the content of the additive in the cellulose acylate film preferably satisfies the relationship expressed by the following formula (15), and more preferably satisfies the relationship expressed by the formula (15-1).
Formula (15): 0.9 <Cm _s / Cm ₀ ≦ 1.0
Formula (15-1): 0.95 <Cm _s / Cm ₀ ≦ 1.0
(Wherein, Cm ₀ is content in the pre-saponification treatment, Cm _s is the content after saponification.)

  In the cellulose acylate film of the present invention, the contact angle of the film surface after the alkali saponification treatment is preferably 55 ° or less. More preferably, it is 50 ° or less, and further preferably 45 ° or less. The contact angle evaluation method can be used as an evaluation of hydrophilicity / hydrophobicity by an ordinary method in which a water droplet having a diameter of 3 mm is dropped on the surface of the film after the alkali saponification treatment and the angle formed by the film surface and the water droplet is determined.

  In general, the surface energy of a solid can be determined by a contact angle method, a wet heat method, and an adsorption method as described in “Basics and Applications of Wetting” (issued by Realize 1989.12.10). In the case of the cellulose acylate film of the present invention, it is preferable to use a contact angle method. Specifically, two kinds of solutions having known surface energies are dropped on a cellulose acylate film, and at the intersection of the surface of the droplet and the surface of the film, the angle formed between the tangent line drawn on the droplet and the film surface, The surface angle of the film can be calculated by defining the angle containing the droplet as the contact angle.

(Changes in Re and Rth values before and after saponification of the film surface)
In the cellulose acylate film of the present invention, the change in Re and Rth values at a wavelength of 630 nm before and after the saponification treatment of the film surface with an alkaline solution preferably satisfies the relationship of the following formula (16). It is more preferable to satisfy the relationship of -1), and it is more preferable to satisfy the relationship of Formula (16-2).
Equation (16): | Re _{630 (0)} −Re _{630 (s)} | ≦ 10 and | Rth _{630 (0)} −Rth _{630 (s)} | ≦ 20
Formula (16-1): | Re _{630 (0)} −Re _{630 (s)} | ≦ 8 and | Rth _{630 (0)} −Rth _{630 (s)} | ≦ 15
Formula (16-2): | Re _{630 (0)} −Re _{630 (s)} | ≦ 5 and | Rth _{630 (0)} −Rth _{630 (s)} | ≦ 10.
In the above formula, Re _{630 (0)} represents Re at a wavelength of 630 nm before saponification with an alkaline solution, Re _{630 (s)} represents Re at a wavelength of 630 nm after saponification with an alkaline solution, and Rth _{630 (0)} represents an alkaline solution. Rth and Rth _{630 (s) at} a wavelength of 630 nm before saponification with γ represent Rth at a wavelength of 630 nm after saponification with an alkaline solution.
If it is in said range, when it applies to a polarizing plate, an optical compensation film, and a liquid crystal display device, the optical performance of a protective film is not inferior, and a light leak does not occur.

  The specific alkali saponification treatment in the present invention means that a 10 cm × 10 cm film sample is immersed in a 1.5 mol / L sodium hydroxide aqueous solution for 2 minutes at 55 ° C. and then 0.05 mol / L at 30 ° C. It is a procedure of neutralizing with a sulfuric acid solution of L, washing in a water bath at room temperature, and drying at 100 ° C.

[Light resistance]
As an index of light durability of the cellulose acylate film of the present invention, a change in Rth value of a film irradiated with super xenon light for 200 hours was measured. Xenon light irradiation is a cellulose acylate film alone, and super xenon weather meter “SX-75” {manufactured by Suga Test Instruments Co., Ltd., 60 ° C., 50% RH condition} with xenon light at 250,000 Lx for 200 hours. Irradiated. After the elapse of a predetermined time, the film was taken out of the thermostatic bath, and after humidity adjustment was performed in the same manner as described above, the film was measured.

Alternatively, it is also possible to use a color difference ΔE ^* a ^* b ^* as an index of light endurance, a super xenon light was irradiated under the same conditions as described above, that the front and rear of the color difference ΔE ^* a ^* b ^* is 20 or less Is preferred. More preferably, it is 18 or less, and it is still more preferable that it is 15 or less.

For the measurement of color difference, “UV3100” {manufactured by Shimadzu Corporation} was used. The method of measurement is that the film is conditioned at 25 ° C. and 60% RH for 2 hours or more, then color measurement of the film before xenon light irradiation is performed, and the initial values (L ₀ ^* , a ₀ ^* , b ₀ ^* ) are set. Asked. Then, the film itself was irradiated with xenon light under the conditions of 60 ° C. and 50% RH. After a predetermined time, the film was taken out of the thermostatic bath, adjusted to 25 ° C. and 60% RH for 2 hours, and then again colored. Measurement was carried out to determine values after irradiation (L ₁ ^* , a ₁ ^* , b ₁ ^* ). From these, the color difference ΔE ^* a ^* b ^* was determined according to the following formula (17). For the light resistance test, carbon arc irradiation, which is a similar accelerated test, may be used.
Formula (17): ΔE ^* a ^* b ^* = [(L ₀ ^* −L ₁ ^* ) ² + (a ₀ ^* −a ₁ ^* ) ² + (b ₀ ^* −b ₁ ^* ) ² ] ^1/2 .

<Uses of cellulose acylate film>
[Optical use]
The cellulose acylate film of the present invention is applied to optical uses and photographic light-sensitive materials as its uses. In particular, it is preferably used for a liquid crystal display device as an optical application. The liquid crystal display device is generally configured by disposing a liquid crystal cell in which liquid crystal is supported between two electrode substrates, and two polarizing plates disposed on both sides thereof, and the cellulose acylate film of the present invention includes: It is more preferable to use it for a liquid crystal display device as a protective film for a polarizing plate or by providing a functional layer described later. As these liquid crystal display devices, TN, IPS, FLC, AFLC, OCB, STN, ECB, VA and HAN are preferable.

[Functional layer]
When the cellulose acylate film of the present invention is used for the above optical use, various functional layers are provided. They are, for example, an antistatic layer, a cured resin layer (transparent hard coat layer), an antireflection layer, an easy adhesion layer, an antiglare layer, an optical compensation layer, an alignment layer, a liquid crystal layer, and the like.

  Examples of these functional layers and materials for which the cellulose acylate film of the present invention can be used include surfactants, slip agents, matting agents, antistatic layers, hard coat layers, and the like. No. 2001-1745, issued on March 15, 2001, Invention Association), which is described in detail on pages 32 to 45, and can be preferably used in the present invention.

[Application (Polarizing plate)]
The use of the cellulose acylate film of the present invention will be described.
The cellulose acylate film of the present invention is particularly useful as a polarizing plate protective film. When using as a polarizing plate protective film, the preparation method of a polarizing plate is not specifically limited, It can produce by a general method. The obtained cellulose acylate film has a surface treated with an alkali, and is bonded to both sides of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution or the like. is there. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed.

  Examples of the adhesive used to bond the protective film treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like.

The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and further includes a protective film on one surface of the polarizing plate and a separate film on the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protective film is bonded for the purpose of protecting the surface of the polarizing plate, used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate, and the separate film is bonded to the liquid crystal cell. It is used for the purpose of covering the layer, and is used on the surface side where the polarizing plate is bonded to the liquid crystal plate.

  In a liquid crystal display device, a substrate containing liquid crystal is usually disposed between two polarizing plates, but the polarizing plate protective film to which the cellulose acylate film of the present invention is applied is excellent in any position. Sex is obtained. In particular, the polarizing plate protective film on the outermost surface of the display side of the liquid crystal display device is provided with a transparent hard coat layer, an antiglare layer, an antireflection layer, and the like. preferable.

[Application (Optical compensation film)]
The cellulose acylate film of the present invention can be used in various applications, and is particularly effective when used as an optical compensation film for liquid crystal display devices. The optical compensation film is generally used for a liquid crystal display device, refers to an optical material that compensates for a phase difference, and is synonymous with a phase difference plate, an optical compensation sheet, and the like. The optical compensation film has birefringence and is used for the purpose of removing the color of the display screen of the liquid crystal display device or improving the viewing angle characteristics.

  Therefore, when the cellulose acylate film of the present invention is used as an optical compensation film of a liquid crystal display device, Re and Rth of the optically anisotropic layer used in combination are Re = 0 to 200 nm and | Rth | = 0 to 400 nm. Any optically anisotropic layer may be used as long as it is within this range.

  The optical performance and driving method of the liquid crystal cell of the liquid crystal display device in which the cellulose acylate film of the present invention is used are not particularly limited, and any optical anisotropic layer required as an optical compensation film is used in combination. be able to. The optically anisotropic layer used in combination may be formed from a composition containing a liquid crystalline compound or may be formed from a polymer film having birefringence.

(Optically anisotropic layer containing liquid crystalline compound)
When using an optically anisotropic layer containing a liquid crystalline compound, the liquid crystalline compound is preferably a discotic liquid crystalline compound or a rod-shaped liquid crystalline compound.

(Discotic liquid crystalline compounds)
Examples of discotic liquid crystalline compounds that can be used in the present invention include various documents [C. Destrade et al., “Mol. Crysr. Liq. Cryst.”, 71, p. 111 (1981); edited by The Chemical Society of Japan, “Quarterly Chemistry Review”, No. 22, “Chemicals of Liquid Crystals”, Chapter 5, Chapter 10, Section 2 (1994); Kohne et al., “Angew. Chem. Soc. Chem. Comm.”, P. 1794 (1985); Zhang et al., “J. Am. Chem. Soc.”, 116, p. 2655 (1994)].

  In the optically anisotropic layer, the molecules of the discotic liquid crystalline compound are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. The polymerization of discotic liquid crystalline compounds 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. JP-A-2001-4387 discloses a discotic liquid crystalline compound having a polymerizable group.

(Bar-shaped liquid crystalline compound)
Examples of rod-like liquid crystalline compounds that can be used in the present invention include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, and cyano-substituted compounds. Phenyl pyrimidines, alkoxy substituted phenyl pyrimidines, phenyl dioxanes, tolanes and alkenyl cyclohexyl benzonitriles are included. Not only the above low-molecular liquid crystalline compounds but also high-molecular liquid crystalline compounds can be used.

  In the optically anisotropic layer, the rod-like liquid crystal compound molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Examples of polymerizable rod-like liquid crystal compounds that can be used in the present invention include “Makromol. Chem.”, 190, 2255 (1989), “Advanced Materials”, 5, 107 (1993), USA. Patent Nos. 4,683,327, 5,622,648, 5,770,107, WO95 / 22586, 95/24455, 97/00600, 98/98. No. 23580, No. 98/52905, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, JP-A-2001-328773, etc. Are included.

(Optically anisotropic layer made of polymer film)
As described above, the optically anisotropic layer in the present invention may be formed from a polymer film. The polymer film is formed from a polymer that can exhibit optical anisotropy. Examples of such polymers include polyolefins (eg, polyethylene, polypropylene, norbornene polymers), polycarbonates, polyarylate, polysulfone, polyvinyl alcohol, polymethacrylic acid esters, polyacrylic acid esters and cellulose esters (eg, cellulose tria). Sate, cellulose diacetate, etc.). Moreover, you may use the copolymer or polymer mixture of these polymers.

  The optical anisotropy of the polymer film is preferably obtained by stretching. The stretching is preferably uniaxial stretching or biaxial stretching. Specifically, longitudinal uniaxial stretching using a difference in peripheral speed between two or more rolls, tenter stretching for grasping both sides of the polymer film and stretching in the width direction, or biaxial stretching in combination of these is preferable. In addition, using two or more polymer films, the optical properties of the entire two or more films may satisfy the above conditions. The polymer film is preferably produced by a solvent cast method in order to reduce unevenness in birefringence. The thickness of the polymer film is preferably 20 to 500 μm, and most preferably 40 to 100 μm.

Further, as the polymer film forming the optically anisotropic layer, at least one polymer material selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide polyesterimide, and polyaryletherketone is used. A method in which a solution in which is dissolved in a solvent is applied to a substrate and the solvent is dried to form a film can also be preferably used.
At this time, the polymer film and the base material are stretched to develop optical anisotropy, and a method of using as an optically anisotropic layer can also be preferably used. In this case, the cellulose acylate film of the present invention is used in this case. It can preferably be used as a base material. Moreover, after preparing these polymer films on another base material, and peeling the polymer film from a base material, it bonds with the cellulose acylate film of this invention, and is used as an optically anisotropic layer. It is also preferable to use it. In this method, the thickness of the polymer film can be reduced, and the thickness is preferably 50 μm or less, and more preferably 1 to 20 μm.

[Configuration of general liquid crystal display device]
When the cellulose acylate film is used as an optical compensation film, the transmission axis of the polarizing element and the slow axis of the optical compensation film made of the cellulose acylate film may be arranged at any angle. The liquid crystal display device includes a liquid crystal cell in which liquid crystal is supported between two electrode substrates, two polarizing elements disposed on both sides thereof, and at least one sheet between the liquid crystal cell and the polarizing element. The optical compensation film is arranged.

  The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

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

(TN type liquid crystal display device)
The cellulose acylate film of the present invention may be used as a support for an optical compensation film of a TN type liquid crystal display device having a TN mode liquid crystal cell or as a protective film for a polarizing plate. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. The optical compensation film used for the TN type liquid crystal display device is described in JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572. Further, it is described in a paper by Mori et al. ("Jpn. J. Appl. Phys.", Volume 36 (1997), p. 143 and p. 1068).

(STN type liquid crystal display device)
The cellulose acylate film of the present invention may be used as a support for an optical compensation film of an STN type liquid crystal display device having an STN mode liquid crystal cell. In general, in the STN type liquid crystal display device, the molecules of the rod-like liquid crystalline compound in the liquid crystal cell are twisted in the range of 90 to 360 °, and the refractive index anisotropy (Δn) of the rod-like liquid crystalline compound and the cell gap ( The product (Δn · d) with d) is in the range of 300 to 1500 nm. The optical compensation film used for the STN type liquid crystal display device is described in JP-A No. 2000-105316.

(VA type liquid crystal display device)
The cellulose acylate film of the present invention is particularly advantageously used as a support for an optical compensation film of a VA liquid crystal display device having a VA mode liquid crystal cell. It is preferable that the retardation value Re of the optical compensation film used in the VA liquid crystal display device is 0 to 150 nm and the retardation value Rth is 70 to 400 nm. The retardation value Re is more preferably 20 to 70 nm. When two optically anisotropic polymer films are used in the VA liquid crystal display device, the retardation value Re of the film is preferably 70 to 250 nm. When a single optically anisotropic polymer film is used for the VA liquid crystal display device, the retardation value Rth of the film is preferably 150 to 400 nm. The VA-type liquid crystal display device may be an alignment-divided system as described in, for example, JP-A-10-123576.

(IPS liquid crystal display device and ECB liquid crystal display device)
The cellulose acylate film of the present invention is particularly advantageous as a support for an optical compensation film of an IPS liquid crystal display device and an ECB liquid crystal display device having a liquid crystal cell of IPS mode and ECB mode, or as a protective film for a polarizing plate. Used. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and in a state where no voltage is applied, the liquid crystal molecules are aligned parallel to the substrate surface to display black. In these embodiments, the polarizing plate using the cellulose acylate film of the present invention contributes to the improvement of the tint, the expansion of the viewing angle, and the improvement of the contrast. In this aspect, the cellulose acylate film of the present invention is applied to the protective film (the protective film on the cell side) disposed between the liquid crystal cell and the polarizing plate among the protective films of the polarizing plate above and below the liquid crystal cell. The polarizing plate used is preferably used at least on one side of the liquid crystal cell. More preferably, an optically anisotropic layer is disposed between the protective film of the polarizing plate and the liquid crystal cell, and the retardation value of the disposed optically anisotropic layer is twice the value of Δn · d of the liquid crystal layer. It is preferable to set as follows.

(OCB type liquid crystal display device and HAN type liquid crystal display device)
The cellulose acylate film of the present invention is also advantageously used as a support for an optical compensation film of an OCB type liquid crystal display device having an OCB mode liquid crystal cell or a HAN type liquid crystal display device having a HAN mode liquid crystal cell. The optical compensation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device may not have a direction in which the absolute value of the retardation is minimized, neither in the plane of the optical compensation film nor in the normal direction. preferable. The optical properties of the optical compensation film used in the OCB type liquid crystal display device or HAN type liquid crystal display device are also the optical properties of the optically anisotropic layer, the optical properties of the support, and the arrangement of the optically anisotropic layer and the support. Determined by. An optical compensation film used for an OCB type liquid crystal display device or a HAN type liquid crystal display device is described in JP-A-9-197397. Also, Mori et al., “Jpn. J. Appl. Phys.”, 38 (1999) p. 2837}.

(Reflective liquid crystal display)
The cellulose acylate film of the present invention is also advantageously used for an optical compensation film of a TN type, STN type, HAN type, GH (Guest-Host) type reflective liquid crystal display device. These display modes have been well known since ancient times. The TN type reflection type liquid crystal display device is described in JP-A-10-123478, International Publication No. 98/48320, and Japanese Patent No. 3022477. The optical compensation film used in the reflective liquid crystal display device is described in International Publication No. 00/65384 pamphlet.

(Other liquid crystal display devices)
The cellulose acylate film of the present invention is also advantageously used as a support for an optical compensation film of an ASM type liquid crystal display device having a liquid crystal cell in an ASM (axially aligned microcell) mode. The ASM mode liquid crystal cell is characterized in that the thickness of the cell is maintained by a resin spacer whose position can be adjusted. Other properties are the same as those of the TN mode liquid crystal cell. The ASM mode liquid crystal cell and the ASM type liquid crystal display device are described in a paper by Kume et al. {Kume et al. , "SID 98 Digest 1089" (1998)}.

[Hard coat film, antiglare film, antireflection film]
The cellulose acylate film of the present invention can be preferably applied to a hard coat film, an antiglare film and an antireflection film. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., one or both of a hard coat layer, an antiglare layer and an antireflection layer on one side or both sides of the cellulose acylate film of the present invention or their All can be granted. Preferred embodiments of such an antiglare film and antireflection film are described in detail in pages 54 to 57 of the Japan Institute of Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention). The cellulose acylate film of the present invention can be preferably used.

[Photographic film support]
Furthermore, the cellulose acylate film of the present invention can be applied as a support for silver halide photographic light-sensitive materials, and various materials and formulations described in the patent specifications of the photographic light-sensitive materials, and further processing methods can be applied. . Regarding these techniques, Japanese Patent Application Laid-Open No. 2000-105445 discloses details regarding color negatives, and the cellulose acylate film of the present invention is preferably used. Further, application as a support for a color reversal silver halide photographic light-sensitive material is also preferable, and various materials, formulations and processing methods described in JP-A No. 11-282119 can be applied.

[Transparent substrate of liquid crystal cell]
Since the cellulose acylate film of the present invention has an optical anisotropy close to zero and excellent transparency, it is an alternative to the liquid crystal cell glass substrate of a liquid crystal display device, that is, as a transparent substrate that encloses driving liquid crystals. Can also be used.

Since the transparent substrate enclosing the liquid crystal needs to be excellent in gas barrier properties, a gas barrier layer may be provided on the surface of the cellulose acylate film of the present invention as necessary. Although the form and material of the gas barrier layer are not particularly limited, SiO ₂ or the like is vapor-deposited on at least one surface of the cellulose acylate film of the present invention, or a relative gas barrier such as vinylidene chloride polymer or vinyl alcohol polymer. A method of providing a high polymer coating layer can be considered, and these can be used as appropriate.

  In order to use as a transparent substrate for enclosing liquid crystal, a transparent electrode for driving the liquid crystal by applying a voltage may be provided. Although a transparent electrode is not specifically limited, It can form by laminating | stacking a metal film, a metal oxide film, etc. on the at least single side | surface of the cellulose acylate film of this invention. Among these, a metal oxide film is preferable from the viewpoint of transparency, conductivity, and mechanical characteristics, and an indium oxide thin film mainly containing tin oxide and containing 2 to 15% by mass of zinc oxide can be preferably used. Details of these techniques are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2001-125079 and 2000-227603.

  Examples of the present invention will be given below, but the present invention is not limited thereto.

<Preparation of cellulose acylate film>
Example 1-1
[Preparation of Cellulose Acylate Stock Solution (CAL-1)]
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution stock solution (CAL-1).

{Composition of cellulose acylate stock solution (CAL-1)}
Cellulose acylate 100 parts by mass Acetyl substitution degree 2.92, average polymerization degree 310
Methylene chloride (first solvent) 402 parts by mass Methanol (second solvent) 60 parts by mass

[Preparation of matting agent solution (ML-1)]
The following composition was put into a disperser and stirred to dissolve each component to prepare a matting agent solution (ML-1).

{Matting agent solution (ML-1) composition}
Silica particle dispersion (average particle size 16 nm) 10.0 parts by mass “AEROSIL R972”, Nippon Aerosil Co., Ltd. methylene chloride (first solvent) 76.3 parts by mass Methanol (second solvent) 3.4 parts by mass Cellulose Acylate undiluted solution (CAL-1) 10.3 parts by mass

[Preparation of Retardation Regulator Solution (REL1-1)]
The following composition was put into another mixing tank and stirred while heating to dissolve each component to prepare a retardation adjusting agent solution (REL1-1).

{Retardation modifier solution (REL1-1) composition}
Wavelength dispersion adjusting agent (UV-1) having the following structure 2.5 parts by mass Wavelength dispersion adjusting agent (UV-2) having the following structure 2.6 parts by mass Wavelength dispersion adjusting agent (UV-3) having the following structure 2.5 parts by mass Part Retardation regulator (A-1) 49.3 parts by weight Compound (H-7) expressing hydrophobicity 20.5 parts by weight Methylene lylide (first solvent) 58.4 parts by weight Ethanol (second solvent) 8.7 parts by mass Cellulose acylate stock solution (CAL-1) 12.8 parts by mass

[Production of Cellulose Acylate Film (101)]
After filtration, 94.6 parts by mass of cellulose acylate solution (CAL-1), 1.3 parts by mass of matting agent solution (ML-1), and 4.7 parts by mass of retardation regulator solution (REL-1) were filtered. The mixture was put into a mixing vessel and sufficiently stirred while heating to dissolve each component to prepare a dope (DP1-1). The obtained dope (DP1-1) was cast using a band casting machine. After peeling off at a residual solvent amount of 42% by mass, it was dried at 140 ° C. for 40 minutes to prepare a cellulose acylate film sample (101) having a thickness of 80 μm.

  In said composition, the addition amount with respect to 100 mass parts of cellulose acylates is 12.0 mass parts for the retardation modifier (A-1), and 5.0 mass parts for the compound (H-7) expressing hydrophobicity. there were.

Examples 1-2 to 1-9 and Comparative Examples 1-1 to 1-4
[Preparation of Retardation Modifier Solutions (REL1-2) to (REL1-13)]
In the preparation of the retardation modifier solution (REL1-1), as shown in Table 1, the type of the retardation modifier is changed and / or the type of the compound expressing hydrophobicity is changed, or this is not used. Prepared retardation modifier solutions (REL1-2) to (REL1-13) in the same manner as in the preparation of the retardation modifier solution (REL1-1). The retardation regulator used and the compound that exhibits hydrophobicity are both compounds having a molecular weight of 1000 or less.

[Production of Cellulose Acylate Films (102) to (113)]
In the production of the cellulose acylate film (101) of Example 1-1, instead of using the retardation modifier solution (REL1-1), any one of the retardation modifier solutions (REL1-2) to (REL1-13). A cellulose acylate film sample was prepared in the same manner as in Example 1-1 except that the dopes (DP1-2) to (DP1-13) were prepared using, and a cellulose acylate film was prepared using each of the obtained dopes. (102) to (113) were produced. The film thicknesses of the cellulose acylate film samples (102) to (113) were all in the range of 79.5 to 80.5 μm. In the samples (101) to (114), the difference between the maximum value and the minimum value of the 1 m square film cut out arbitrarily was within 5% of the average thickness.

  The chemical structures of triphenyl phosphate (TPP) and biphenyl diphenyl phosphate (BDP) in Table 1 are as follows.

Table 2 shows the measurement results of various retardation characteristics, equilibrium water content, moisture permeability, hygroscopic expansion coefficient, and the following environmental changes of the obtained cellulose acylate films (102) to (113).
The dispersion of Re and Rth of the cellulose acylate film samples (101) to (114) within the 1 m square film is | Re _{630 (max)} −Re _{630 (min)} | , | Rth _{630 (max)} −Rth _{630 (min)} | was 5 nm or less, which was preferable.

[Changes in optical performance over time with environmental changes]
Cellulose acylate film samples (101) to (113) were each stored for 14 days under the following two conditions.
(1) 60 ° C., 90% RH; (2) 60 ° C., 30% RH.
The Rth of the film sample subjected to the conditions (1) and (2) was measured after humidity adjustment as described above, and the absolute value of the difference between the measured values was calculated.

  As can be seen from the results in Table 2 above, at least one retardation regulator, at least one hydrogen bond donating group, and a hydrophobicity with an octanol / water partition coefficient (log P) of 1 or more and 8 or less are expressed. The cellulose acylate film of the present invention, which is used in combination with the compound to be used, can achieve both durability and low optical anisotropy.

Example 2
[Preparation of Cellulose Acylate Stock Solution (CAL-2)]
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate stock solution (CAL-2).

{Composition of cellulose acylate stock solution (CAL-2)}
Cellulose acylate 100 parts by mass Acetyl substitution degree 2.86, average polymerization degree 310
Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 400 parts by weight Methanol (second solvent) 60 parts by weight

[Preparation of Retardation Regulator Solution (REL2-1)]
The following composition was put into another mixing tank and stirred while heating to dissolve each component to prepare a retardation adjusting agent solution (REL2-1).

{Retardation modifier solution (REL2-1) composition}
1.0 part by weight of the wavelength dispersion adjusting agent (UV-1) having the above structure 1.0 part by weight of the wavelength dispersion adjusting agent (UV-4) having the following structure 2.0 parts by weight Part Retardation modifier (A-14) 40.0 parts by mass Hydrophobic compound (H-7) 20.0 parts by mass Methylene lide (first solvent) 80.0 parts by mass Methanol (second solvent) 20.0 parts by mass

[Production of Cellulose Acylate Film (201)]
To 477 parts by mass of the cellulose acylate stock solution (CAL-2), 45 parts by mass of the retardation modifier solution (REL2-1) was added and stirred sufficiently to prepare a dope (DP2-1). The obtained dope (DP2-1) was cast on a drum cooled to 0 ° C. from the casting port. When the solvent content becomes 55% by mass, the film is peeled off and both ends in the width direction of the film are fixed with a pin tenter (the pin tenter described in FIG. 3 of JP-A-4-1009), and the solvent content is 3 to 5 In a mass% state, the film was dried while maintaining an interval so that the stretching ratio in the width direction (direction perpendicular to the machine direction) was 12%. Then, it dried further by conveying between the rolls of a heat processing apparatus, and produced the 80-micrometer-thick cellulose acylate film sample (201).

The cellulose acylate film sample (201) thus produced was evaluated in the same manner as in Example 1. As a result, both Re and Rth were found to be preferable. Further, the rate of change of Re by stretching of the cellulose acylate film sample (201) {| Re _(n) −Re ₍₀₎ | / n: Re _(n) is Re, Re ₍₀ ) of the film stretched by n (%). ₎ Shows that Re} of the unstretched film is 0.17, and the change in Re before and after stretching is small and preferable.

<Preparation of polarizing plate>
Example 11
[Saponification]
The cellulose acylate film sample (103) produced in Example 1 was immersed in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing bath, and neutralized using 0.05 mol / L sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, the surface of the cellulose acylate film was saponified.

[Preparation of polarizing plate]
A polarizer was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the saponified cellulose acylate film sample (103) was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizer were arranged in parallel.

  A commercially available cellulose triacetate film “Fujitac TD80UF” (manufactured by Fuji Photo Film Co., Ltd.) was saponified in the same manner as described above, and attached to the opposite side of the polarizer using a polyvinyl alcohol-based adhesive. In this way, a polarizing plate (P-1) was produced.

[Preparation of polarizing plate with retardation film]
The thickness 100μm norbornene resin film {JSR (Co., Ltd.), "ARTON"} of, by stretching at 175 ° C. at a tenter stretching machine, has a refractive index properties of n _x> n _y> n _z A retardation film having a Re of 40 nm and an Rth of 30 nm is prepared and attached to the cellulose acylate film (103) side of the polarizing plate (P-1) using an adhesive to prepare a polarizing plate with a retardation film. did.

Example 21
[Evaluation of mounting on IPS liquid crystal display]
Using the cellulose acylate film sample (104) of the present invention prepared in Example 1, a uniaxially stretched optical compensation film was bonded to the polarizing plate (P-2) prepared in the same manner as in Example 21. Thus, an optical compensation function was provided. At this time, visual characteristics could be improved without changing the front characteristics at all by making the slow axis of the front retardation of the optical compensation film orthogonal to the transmission axis of the polarizing plate. The optical compensation film used had a retardation Re in the front direction of 270 nm, a retardation Rth in the thickness direction of 0 nm, and an Nz factor of 0.5.

  A laminate of a polarizing plate and an optical compensation film using the cellulose acylate film sample (104) of the present invention produced as described above, an IPS type liquid crystal cell, and a cellulose acylate film sample (101) of the present invention. A display device in which the polarizing plates using were stacked in the order of the polarizing plates was prepared. At this time, the transmission axes of the upper and lower polarizing plates are orthogonal to each other, and the transmission axis of the upper polarizing plate is parallel to the molecular long axis direction of the liquid crystal cell (that is, the slow axis of the optical compensation layer and the molecular long axis direction of the liquid crystal cell are Orthogonal). As the liquid crystal cell, electrode and substrate, those conventionally used as IPS can be used as they are. The alignment of the liquid crystal cell is horizontal alignment, and the liquid crystal has a positive dielectric anisotropy, and those developed and marketed for IPS liquid crystals can be used. The physical properties of the liquid crystal cell were as follows: Δn of liquid crystal: 0.099, cell gap of liquid crystal layer: 3.0 μm, pretilt angle: 5 °, rubbing direction: 75 ° above and below the substrate.

  In the liquid crystal display device produced as described above, the light leakage rate at the time of black display in the azimuth direction 45 ° and polar angle direction 70 ° from the front of the device was measured, and the liquid crystal display device was produced using the cellulose acylate film of the present invention. It was found that the optical compensation film and the polarizing plate have a wide contrast viewing angle and are preferable.

It is explanatory drawing which showed the structural example which compounded the polarizing plate of this invention, and a functional optical film. It is explanatory drawing which showed an example of the liquid crystal display device in which the polarizing plate of this invention is used.

Explanation of symbols

1, 1a, 1b: protective film 2: polarizer 3: functional optical film 4: adhesive layer 11: upper polarizing plate 12: upper polarizing plate absorption axis 13: upper optical anisotropic layer 14: upper optical anisotropic layer Alignment control direction 15: Liquid crystal cell upper substrate 16: Upper substrate alignment control direction 17: Liquid crystal molecule 18: Liquid crystal cell lower substrate 19: Lower substrate alignment control direction 20: Lower optical anisotropic layer 21: Lower optical anisotropic layer Orientation control direction 22: Lower polarizing plate 23: Lower polarizing plate absorption axis

Claims (19)

  It contains at least one kind of retardation regulator and at least one compound having at least one hydrogen bond donating group and expressing hydrophobicity having an octanol / water partition coefficient (log P) of 1 or more and 8 or less. Characteristic cellulose acylate film. The cellulose acylate film according to claim 1, wherein the retardation regulator is at least one selected from compounds represented by the following general formulas (1) to (6).
General formula (1):

{In General Formula (1), R ¹¹ represents an aryl group. R ¹² and R ¹³ each independently represents an alkyl group or an aryl group, and at least one of them is an aryl group. Moreover, the alkyl group and the aryl group may each have a substituent. }
General formula (2):

{In General Formula (2), R ²¹ , R ²² and R ²³ each independently represents an alkyl group. Moreover, each alkyl group may have a substituent. }
General formula (3):

{In General Formula (3), R ³¹ , R ³² , R ³³ and R ³⁴ each represent a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group. X ³¹ , X ³² , X ³³ and X ³⁴ are each a single bond, —CO— and NR ³⁵ — (R ³⁵ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group). Represents a divalent linking group formed from one or more groups selected from the group consisting of: a, b, c and d are integers of 0 or more, and a + b + c + d is 2 or more. Z ³¹ represents an (a + b + c + d) -valent organic group (excluding a cyclic group). }
General formula (4):

{In General Formula (4), R ⁴¹ represents an alkyl group or an aryl group, and R ⁴² and R ⁴³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. The total number of carbon atoms of R ⁴¹ , R ⁴² and R ⁴³ is 10 or more. }
General formula (5):

{In General Formula (5), R ⁵¹ and R ⁵² each independently represents an alkyl group or an aryl group. The total number of carbon atoms of R ⁵¹ and R ⁵² is 10 or more. }
General formula (6):

{In General Formula (6), R ⁶¹ represents a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group, and R ⁶² represents a hydrogen atom, a substituted or unsubstituted aliphatic group, Represents an unsubstituted aromatic group. L ⁶¹ represents a divalent to hexavalent linking group, and e represents an integer of 2 to 6 depending on the valence of L ⁶¹ . }   The cellulose acylate film according to claim 2, wherein the retardation regulator is at least one selected from the compounds represented by formulas (1) to (3). The cellulose acylate film according to claim 1, wherein the compound that exhibits hydrophobicity is represented by the following general formula (7).
General formula (7):

{In General Formula (7), ^X71 represents a boron atom, C- ^R71 ( ^R71 represents a hydrogen atom or a substituent), a nitrogen atom, a phosphorus atom, or P = O. R ⁷¹¹ , R ⁷¹² , R ⁷¹³ , R ⁷¹⁴ , R ⁷¹⁵ , R ⁷²¹ , R ⁷²² , R ⁷²³ , R ⁷²⁴ , R ⁷²⁵ , R ⁷³¹ , R ⁷³² , R ⁷³³ , R ⁷³⁴ , and R ⁷³⁵ are each independently Represents a hydrogen atom or a substituent} The cellulose acylate film according to any one of claims 1 to 4, wherein Rth and Re at a wavelength of 630 nm of the cellulose acylate film each satisfy a range of the following formula (1).
Formula (1): −25 nm ≦ Rth ₆₃₀ ≦ 25 nm and 0 nm ≦ Re ₆₃₀ ≦ 10 nm   The cellulose acylate film according to any one of claims 1 to 5, wherein, in a wavelength range of 400 nm to 700 nm, the Rth variation of the cellulose acylate film is 25 nm or less and the Re variation is 10 nm or less. The cellulose acylate film according to any one of claims 1 to 6, wherein the values of Re and Rth at a wavelength of 630 nm of the cellulose acylate film satisfy at least one of the relations of the following mathematical formulas (2) and (3).
Formula (2): | Re ₆₃₀ × Rth ₆₃₀ | ≦ 200
Formula (3): 0.5 ≦ Rth ₆₃₀ / Re ₆₃₀ ≦ 5.0 (where Re ₆₃₀ ≧ 1) The cellulose acylate film according to any one of claims 1 to 7, wherein the values of Re and Rth at a wavelength of 630 nm of the cellulose acylate film satisfy the relationship of the following mathematical formula (4).
Formula (4): | Re _{630 (max)} −Re _{630 (min)} | ≦ 5 and | Rth _{630 (max)} −Rth _{630 (min)} | ≦ 10
{In the formula, Re _{630 (max)} and Rth _{630 (max)} are the maximum retardation values at a wavelength of 630 nm of an arbitrarily cut out 1 m square film, and Re _{630 (min)} and Rth _{630 (min)} are the minimum at a wavelength of 630 nm. It is a retardation value. }   The cellulose acylate according to any one of claims 1 to 8, wherein the cellulose acylate constituting the cellulose acylate film has an acyl substitution degree of 2.50 to 3.00 and an average degree of polymerization of 180 to 700. Rate film.   The acyl substituent of the cellulose acylate constituting the cellulose acylate film consists essentially of an acetyl group, the total substitution degree is 2.50 to 2.95, and the average polymerization degree is 180 to 550. Item 10. The cellulose acylate film according to any one of Items 1 to 9.   The cellulose acylate film according to claim 1, wherein the thickness of the cellulose acylate film is 10 to 120 μm.   The cellulose acylate film according to any one of claims 1 to 11, which has an equilibrium moisture content at 25 ° C and 80% RH of 3.2% or less. The cellulose acylate film according to any one of claims 1 to 12, wherein the moisture permeability for 24 hours at 60 ° C and 95% RH is 400 to 2000 g / m ² · 24 h in terms of a film thickness of 80 µm. The cellulose acylate film according to claim 1, which has a hygroscopic expansion coefficient of 30 × 10 ⁻⁵ /% RH or less.   The cellulose acylate film is obtained by stretching, and the stretching ratio is 1% or more and 100% or less in a direction (width direction) perpendicular to the transport direction. The cellulose acylate film described. The cellulose acylate film according to claim 15, wherein in the cellulose acylate film obtained by stretching, Re satisfies a relationship represented by the following formula (5).
Formula (5): | Re _(n) −Re ₍₀₎ | /n≦1.0
{In the formula, Re _(n) is Re of a film stretched by n (%), and Re ₍₀₎ is Re of a film not stretched. }   A polarizing plate comprising protective films bonded to both sides of a polarizer, wherein at least one of the protective films is the cellulose acylate film according to any one of claims 1 to 16. .   A liquid crystal display device comprising a liquid crystal cell and two polarizing plates arranged on both sides thereof, wherein at least one polarizing plate is the polarizing plate according to claim 17.   The liquid crystal display device according to claim 18, wherein the liquid crystal display device is in an IPS mode.

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