JP2011127127A - Cellulose acylate film, polarizing plate, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film which has excellent optical compensatory ability and high productivity. <P>SOLUTION: The cellulose acylate film satisfies the formulas: 50 nm<Re<400 nm, -200 nm≤Rth≤50 nm, and ¾Nz¾≤10 [wherein Re is retardation in in-plane direction of the film; Rth is retardation in the thickness direction of the film; and Nz represents (Rth/Re)+0.5]. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical cellulose acylate film, a polarizing plate using the same as an optical compensation sheet, and a liquid crystal display device including the polarizing plate.

Since liquid crystal display devices have various advantages such as low voltage and low power consumption, and can be reduced in size and thickness, they are widely used in monitors for personal computers, portable devices, and television applications. Yes. For such a liquid crystal display device, various modes have been proposed depending on the alignment state of the liquid crystal molecules in the liquid crystal cell. Conventionally, the alignment state is twisted by about 90 ° from the lower substrate to the upper substrate of the liquid crystal cell. The TN mode to become the mainstream.
In general, a liquid crystal display device includes a liquid crystal cell, an optical compensation sheet, and a polarizer. The optical compensation sheet is used for eliminating image coloring or expanding the viewing angle, and a stretched birefringent film or a film obtained by applying a liquid crystal to a transparent film is used. For example, Patent Document 1 discloses a technique for applying an optical compensation sheet in which a discotic liquid crystal is applied on a triacetyl cellulose film, aligned, and fixed to a TN mode liquid crystal cell to widen the viewing angle.
However, a television-use liquid crystal display device that is expected to be viewed from various angles on a large screen has a strict requirement for viewing angle dependency, and even with the above-described method, the requirement cannot be satisfied. Therefore, liquid crystal display devices different from the TN mode, such as an IPS (In-Plane Switching) mode, an OCB (Optically Compensatory Bend) mode, and a VA (Vertically Aligned) mode, have been studied.

By the way, the cellulose acylate film is characterized by high optical isotropy (low retardation value) as compared with other polymer films. Therefore, a cellulose acylate film is used for an application requiring optical isotropy, for example, a polarizing plate.
On the other hand, the optical compensation sheet (retardation film) of the liquid crystal display device is required to have optical anisotropy (high retardation value).
For this reason, in the technical field of optical materials, a synthetic polymer film is used when optical anisotropy is required for the polymer film, and a cellulose acylate film is used when optical isotropy is required. It was a general principle.
As a film that requires optical anisotropy, for example, a film satisfying 50 nm <Re <400 nm, −200 nm <Rth <50 nm, and | Nz | <10 is required for a compensation film of a liquid crystal display device. As for this, there is an example in which a film such as | Nz | = 0.5 is produced using a heat shrinkable film as an optical compensation film (Patent Document 1). However, in this method, the process is complicated, and it is difficult to increase the line speed in order to sufficiently perform heat shrinkage, and a large amount of heat-shrinkable film is generated, resulting in low productivity and high environmental load. . Furthermore, there is a problem that the variation in the in-plane and thickness direction retardation of the obtained film is large.
On the other hand, with respect to the cellulose acylate film, an example in which a cellulose triacetate having a substitution degree of 2.92 is stretched to produce a film with Re = -50 nm Rth = -35 nm is disclosed (Patent Document 2). However, in this film, since the absolute value of Re is low, changes in viewing angle characteristics cannot be sufficiently suppressed.

JP-A-5-157911 Japanese Patent No. 345779

  In view of the above-described problems of the prior art, an object of the present invention is to provide a film having excellent optical compensation ability and high productivity. Another object of the present invention is to provide a liquid crystal display device with little change in viewing angle characteristics and a polarizing plate for producing the device.

As a result of intensive studies, the present inventor has found that the above object can be achieved according to the present invention having the following configuration.
(1) A cellulose acylate film satisfying the following formula:
50 nm <Re <400 nm
−200 nm ≦ Rth ≦ 50 nm
| Nz | ≦ 10
(In the above formula, Re represents retardation in the in-plane direction of the cellulose acylate film, Rth represents retardation in the thickness direction of the cellulose acylate film, and Nz represents (Rth / Re) +0.5.)
(2) The cellulose acylate film according to (1), wherein the substitution degree of the cellulose acylate contained in the film is 2.85 to 3.00.
(3) The cellulose acylate film according to (1) or (2), wherein the film contains a rod-like compound or a discotic compound.
(4) The cellulose acylate film according to any one of (1) to (3), wherein the width of the film is 0.5 to 3 m.
(5) The cellulose acylate film according to any one of (1) to (4), wherein the film has a thickness of 40 to 200 μm.
(6) The cellulose acylate film according to any one of (1) to (5), wherein a slow axis in the plane of the film is in a direction perpendicular to the machine direction. the film. The machine direction here means the film transport direction in the film forming process.
(7) A polarizing plate comprising a polarizing film and two films provided on both sides thereof, wherein at least one of the films is from the cellulose acylate film according to any one of (1) to (6). A polarizing plate characterized by comprising:
(8) A liquid crystal display device using the polarizing plate according to (7).
(9) The liquid crystal display device according to (8), wherein an IPS liquid crystal display mode is used.
(10) After casting a solution containing cellulose acylate having a substitution degree of 2.85 to 3.00 and at least one of a rod-like compound or a discotic compound on a support, the formed film is peeled and stretched. A method for producing a cellulose acylate film, comprising:
(11) The method for producing a cellulose acylate film according to (10), wherein the film forming speed is 5 to 300 m / min.

  The cellulose acylate film of the present invention is a film having excellent in-plane retardation (Re) expression and a small retardation (Rth) in the thickness direction. The cellulose acylate film can be easily produced with high productivity according to the production method of the present invention. Further, the polarizing plate of the present invention using the cellulose acylate film as a protective film for a polarizer can provide a liquid crystal display device with little change in viewing angle characteristics.

  Hereinafter, the present invention will be described in more detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less” . In the present specification, the description “(meth) acryloyl” means “at least one of acryloyl and methacryloyl”. The same applies to “(meth) acrylate”, “(meth) acrylic acid” and the like. When a hydrogen atom is substituted with an atom other than a hydrogen atom, the atom other than the hydrogen atom is treated as a substituent for convenience.

First, the optical cellulose acylate film of the present invention will be described.
[Cellulose acylate film]
The cellulose acylate film of the present invention is a film containing a cellulose acylate compound and a compound having an ester-substituted cellulose skeleton obtained by introducing a functional group biologically or chemically using cellulose as a raw material. Among these, a cellulose acylate film is more preferable.
Cellulose acylate is an ester of cellulose and acid. The acid constituting the ester is preferably an organic acid, more preferably a carboxylic acid, still more preferably a fatty acid having 2 to 22 carbon atoms, still more preferably a lower fatty acid having 2 to 4 carbon atoms, and most preferably acetic acid. .

Cellulose acylate is an ester of cellulose and carboxylic acid. In cellulose acylate, all or part of the hydrogen atoms of the hydroxyl groups present at the 2-position, 3-position and 6-position of the glucose unit constituting cellulose are substituted with acyl groups. Examples of acyl groups include acetyl, propionyl, butanoyl, isobutanoyl, tert-butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl Group, octadecanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group. Acetyl group, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, tert-butanoyl group, oleoyl group, benzoyl group, naphthylcarbonyl group and cinnamoyl group are preferable, acetyl group, propionyl group and butanoyl group are more preferable. An acetyl group is most preferred.
The cellulose acylate may be an ester of cellulose and a plurality of acids. The cellulose acylate may be substituted with a plurality of acyl groups.

The cellulose acylate preferably has a negative intrinsic birefringence. By stretching by having negative intrinsic birefringence, a specific effect that Rth is reduced is exhibited. Cellulose acylate having a high degree of substitution has a negative intrinsic birefringence.
The degree of substitution of cellulose acylate is preferably 2.85 or more, more preferably 2.88 to 3.00, still more preferably 2.92 to 3.00, and 2.93 to 3.00. Is most preferred. In the present specification, the degree of substitution means the total of the ratios in which the hydrogen atoms of the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are substituted (100% substitution has a substitution degree of 1).

  The basic principle of the cellulose acylate synthesis method is described in Nobuhiko Umeda et al., Wood Chemistry, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method of cellulose acylate is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst. Specifically, cellulose raw materials such as cotton linter and wood pulp are pretreated with an appropriate amount of acetic acid, and then put into a pre-cooled carboxylic acid mixture to be esterified to complete cellulose acylate (2nd, 3rd and 6th). The total degree of acyl substitution at the position is approximately 3.00). The carboxylated mixed solution generally contains acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. The carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system.

  After the acylation reaction is completed, a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc carbonate) is used to partially neutralize the hydrolysis and esterification catalyst of excess carboxylic anhydride remaining in the system. Salt, acetate or oxide) in water. Next, the obtained complete cellulose acylate is saponified and aged by maintaining it at 50 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain a desired degree of acyl substitution and degree of polymerization. To a cellulose acylate having When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized with a neutralizing agent as described above, or in water or dilute sulfuric acid without neutralization. The cellulose acylate solution is added (or water or dilute sulfuric acid is added into the cellulose acylate solution) to separate the cellulose acylate, and the cellulose acylate is obtained by washing and stabilizing treatment.

  The degree of polymerization of the cellulose acylate is preferably from 200 to 700, more preferably from 250 to 550, even more preferably from 250 to 400, and most preferably from 250 to 350 in terms of viscosity average degree of polymerization. The viscosity average degree of polymerization can be measured according to Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pages 105-120, 1962). A method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538.

Cellulose acylate with a small amount of low molecular components has a high average molecular weight (degree of polymerization), but its viscosity is lower than that of ordinary cellulose acylate. 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 components can be performed by washing the cellulose acylate with an appropriate organic solvent. In addition, cellulose acylate having a small amount of low molecular components can be synthesized. 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 of cellulose. When the amount of the sulfuric acid catalyst is in the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized.
The cellulose acylate raw material cotton and the synthesis method are also described in pages 7 to 12 of the Japan Society for Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention).

[Cellulose acylate film]
In the cellulose acylate film, the polymer component constituting the film is preferably substantially composed of cellulose acylate. “Substantially” means 55% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more) of the polymer component. Two or more types of cellulose acylate may be used in combination with the cellulose acylate film.
The cellulose acylate film is preferably produced by a solvent cast method using a cellulose acylate solution.

[State of cellulose acylate]
As a raw material of the cellulose acylate solution, it is preferable to use cellulose acylate particles. 90% by mass or more of the particles to be used preferably have a particle size of 0.5 to 5 mm. Moreover, it is preferable that 50 mass% or more of the particle | grains to be used have a particle size of 1-4 mm. The cellulose acylate particles preferably have a shape as close to a sphere as possible.
The cellulose acylate used for the preparation of the cellulose acylate solution preferably has a water content of 2% by mass or less, more preferably 1% by mass or less, and most preferably 0.7% by mass or less. . Cellulose acylate generally has a moisture content of 2.5 to 5% by mass. Therefore, it is preferable to use v cellulose acylate after drying.

Cellulose acylate is dissolved in an organic solvent to form a solution.
In the present invention, any of a chlorinated solvent containing a chlorinated organic solvent as a main solvent and a non-chlorinated solvent not containing a chlorinated organic solvent can be used as the organic solvent.
[Chlorine solvent]
In preparing the cellulose acylate solution of the present invention, a chlorinated organic solvent is preferably used as the main solvent. In the present invention, the type of the chlorinated organic solvent is not particularly limited as long as the object can be achieved within a range where the cellulose acylate can be dissolved, cast and formed. These chlorinated organic solvents are preferably dichloromethane and chloroform. Particularly preferred is dichloromethane. In addition, there is no particular problem in mixing an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50% by mass of dichloromethane in the total amount of the organic solvent. Other organic solvents used in combination with the chlorinated organic solvent in the present invention will be described below. That is, as another preferable organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Esters, ketones, ethers and alcohols 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 solvent. For example, other functional groups such as alcoholic hydroxyl groups can be used. You may have group simultaneously. In the case of a solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

The alcohol used in combination with the chlorinated organic solvent may be linear, branched or cyclic, and among them, saturated aliphatic hydrocarbon is preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.
Examples of combinations of the chlorinated organic solvent and other organic solvents include the following compositions, but the compositions that can be used in the present invention are not limited to these.

Dichloromethane / methanol / ethanol / butanol (80/10/5/5, parts by mass),
Dichloromethane / acetone / methanol / propanol (80/10/5/5, parts by mass),
Dichloromethane / methanol / butanol / cyclohexane (80/10/5/5, parts by mass),
Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
・ Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (75/10/10/5/7, parts by mass)
・ Dichloromethane / cyclopentanone / methanol / isopropanol (80/10/5/8, part by mass)
Dichloromethane / methyl acetate / butanol (80/10/10, parts by mass),
Dichloromethane / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass)
Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),
・ Dichloromethane / 1, 3 dioxolane / methanol / ethanol (70/20/5/5, part by mass),
Dichloromethane / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),
Dichloromethane / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass),
・ Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (70/10/10/5/5, parts by mass),
Dichloromethane / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),
Dichloromethane / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),
Dichloromethane / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),
Dichloromethane / methanol (85/15, parts by mass),

[Non-chlorine solvents]
Next, a non-chlorine organic solvent that is preferably used in preparing the cellulose acylate solution of the present invention will be described. In the present invention, the non-chlorine organic solvent is not particularly limited as long as the object can be achieved as long as the cellulose acylate can be dissolved and cast and formed into a film. The non-chlorine organic solvent used in the present invention is preferably a solvent selected from esters, ketones and ethers having 3 to 12 carbon atoms. The ester, ketone and ether 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, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The non-chlorine organic solvent used in the above cellulose acylate is selected from the various viewpoints described above, and is preferably as follows. That is, the non-chlorine solvent is preferably a mixed solvent containing the non-chlorine organic solvent as a main solvent, and is a mixed solvent of three or more different solvents, wherein the first solvent is methyl acetate, ethyl acetate, At least one selected from methyl formate, ethyl formate, acetone, dioxolane, and dioxane, or a mixture thereof; the second solvent is selected from ketones having 4 to 7 carbon atoms or acetoacetate; The solvent is a mixed solvent selected from alcohols or hydrocarbons having 1 to 10 carbon atoms, more preferably alcohols having 1 to 8 carbon atoms. Note that when the first solvent is a mixed liquid of two or more kinds of solvents, the second solvent may be omitted. The first solvent is more preferably methyl acetate, acetone, methyl formate, ethyl formate, or a mixture thereof, and the second solvent is preferably methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetyl acetate, or a mixed solvent thereof. It may be.

  The alcohol as the third solvent may be linear, branched or cyclic, and is preferably a saturated aliphatic hydrocarbon. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene. These alcohols and hydrocarbons as the third solvent may be used alone or in combination of two or more, and are not particularly limited. As the third solvent, preferred specific compounds include alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and cyclohexanol, cyclohexane, hexane, Are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol.

The mixing ratio of the above three types of mixed solvents is 20 to 95% by mass for the first solvent, 2 to 60% by mass for the second solvent, and 2 to 30% by mass for the third solvent in the total amount of the mixed solvent. The first solvent is preferably 30 to 90% by mass, the second solvent is 3 to 50% by mass, and the third alcohol is preferably 3 to 25% by mass. . In particular, it is preferable that the first solvent is 30 to 90% by mass, the second solvent is 3 to 30% by mass, and the third solvent is alcohol and 3 to 15% by mass. The non-chlorine-based organic solvent used in the present invention is described in more detail on pages 12 to 16 of the Japan Society for Invention and Innovation (Publication No. 2001-1745, published on March 15, 2001, Japan Institute of Invention). ing.
Although the composition of the preferable non-chlorine-type organic solvent of this invention is mentioned below, the composition which can be used by this invention is not limited to these.

-Methyl acetate / acetone / methanol / ethanol / butanol (75/10/5/5/5, parts by mass),
-Methyl acetate / acetone / methanol / ethanol / propanol (75/10/5/5/5, parts by mass),
Methyl acetate / acetone / methanol / butanol / cyclohexane (75/10/5/5/5, parts by mass),
・ Methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass)
・ Methyl acetate / acetone / ethanol / butanol (82/10/4/4, parts by mass)
・ Methyl acetate / acetone / ethanol / butanol (80/10/4/6, part by mass)
Methyl acetate / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
-Methyl acetate / acetone / methyl ethyl ketone / ethanol / isopropanol (75/10/10/5/7, parts by mass)
Methyl acetate / cyclopentanone / methanol / isopropanol (80/10/5/8, parts by mass),
・ Methyl acetate / acetone / butanol (85/5/5, part by mass),
Methyl acetate / cyclopentanone / acetone / methanol / butanol (60/15/15/5/6, parts by mass),
-Methyl acetate / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass)
・ Methyl acetate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, part by mass),
・ Methyl acetate / 1,3-dioxolane / methanol / ethanol (70/20/5/5, parts by mass),
-Methyl acetate / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),
Methyl acetate / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass),
・ Methyl formate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, part by mass),
-Methyl formate / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),
Acetone / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),
Acetone / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),
Acetone / 1,3-dioxolane / ethanol / butanol (65/20/10/5, parts by mass),
1,3-dioxolane / cyclohexanone / methyl ethyl ketone / methanol / butanol (55/20/10/5/5/5, parts by mass)

Furthermore, the cellulose acylate solution prepared by the following method can also be used.
A method of preparing a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass), adding 2 parts by weight of butanol after filtration and concentration, and methyl acetate / acetone / ethanol / Butanol (84/10/4/2, parts by mass) A method for adding a cellulose acylate solution after filtration and concentration, and adding 4 parts by mass of butanol after addition. Methyl acetate / acetone / ethanol (84/10/6, A method for adding a cellulose acylate solution in 5 parts by mass and adding 5 parts by mass of butanol after filtration / concentration to the cellulose acylate solution (dope) used in the present invention, You may contain dichloromethane in the quantity of 10 mass% or less of the total amount of organic solvents.

[Characteristics of cellulose acylate solution]
The cellulose acylate solution is preferably a solution in which cellulose acylate is dissolved in the organic solvent at a concentration of 10 to 30% by mass in terms of suitability for film casting, and more preferably 13 to 27% by mass. Especially preferably, it is 15-25 mass%. The method for carrying out the cellulose acylate at these concentrations may be carried out so as to obtain a predetermined concentration at the stage of dissolution, or it is prepared as a low-concentration solution (for example, 9 to 14% by mass) and then concentrated as described later. You may adjust to a predetermined high concentration solution by a process. Furthermore, after preparing a high concentration cellulose acylate solution in advance, a predetermined low concentration cellulose acylate solution may be obtained by adding various additives, and the cellulose acylate solution concentration of the present invention is obtained by either method. If implemented, there is no particular problem.

In this invention, it is preferable that the aggregate molecular weight of the cellulose acylate in the diluted solution which made the cellulose acylate solution 0.1-5 mass% with the organic solvent of the same composition is 150,000-15 million, More preferably, it is 9 million. This associated molecular weight can be determined by a static light scattering method. In this case, it is preferable to dissolve so that the inertial square radius required at the same time is 10 to 200 nm. A more preferable inertial square radius is 20 to 200 nm. Furthermore, it is preferable to dissolve so that the second virial coefficient is −2 × 10 ⁻⁴ to + 4 × 10 ^−4, and the second virial coefficient is −2 × 10 ⁻⁴ to + 2 × 10 ^−4. More preferably, it dissolves in
Here, the definition of the associated molecular weight, the inertial square radius and the second virial coefficient in the present invention will be described. These are measured using the static light scattering method according to the following method. Although the measurement is performed in a dilute region for the convenience of the apparatus, these measured values reflect the behavior of the dope in the high concentration region of the present invention.
First, cellulose acylate is dissolved in a solvent used for the dope to prepare 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass% solutions. In order to prevent moisture absorption, the cellulose acylate dried at 120 ° C. for 2 hours is used at 25 ° C. and 10% relative humidity. The dissolution method is carried out according to the method employed at the time of dope dissolution (room temperature dissolution method, cooling dissolution method, high temperature dissolution method). Subsequently, these solutions and the solvent are filtered through a 0.2 μm Teflon filter (Teflon: registered trademark). Then, static light scattering of the filtered solution is measured at intervals of 10 degrees from 30 degrees to 140 degrees at 25 ° C. using a light scattering measuring device (DLS-700 manufactured by Otsuka Electronics Co., Ltd.). The obtained data is analyzed by the BERRY plot method. In addition, the refractive index required for this analysis uses the value of the solvent calculated | required with the Abbe refractive system, and the refractive index gradient (dn / dc) uses the differential refractometer (Otsuka Electronics Co., Ltd. product DRM-1021). Measure using the solvent and solution used for light scattering measurement.

[Preparation of solution]
For the preparation of the cellulose acylate solution (dope), it is preferable to use a high-temperature dissolution method or a cooling dissolution method, and a combination of both can also be used. Regarding the method for preparing the cellulose acylate solution, JP-A-58-127737, JP-A-61-106628, JP-A-2-276830, JP-A-4-259511, JP-A-5-163301, JP-A-9-95544, 10-45950, 10-95854, 11-71463, 11-302388, 11-322946, 11-322947, 11-323017, JP 2000-53784, 2000 -273184 and 2000-273239.
The method for preparing the cellulose acylate solution is also described in Japanese Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Invention Association), page 25.
In addition, when the heating temperature in the high temperature dissolution method is equal to or higher than the boiling point of the organic solvent to be used, heating is performed while applying pressure.
Regarding the step of cooling the mixture of cellulose acylate and solvent, the cooling temperature is not particularly limited, but is preferably −100 ° C. to −10 ° C., more preferably −100 ° C. to −30 ° C., and −100 ° C. to −50. ° C is particularly preferred.

[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 include, for example, the plastic material course (17) Fibrous resin (manufactured by Marusawa and Uda, Nikkan Kogyo Shimbun, published in 1970), and the Japan Institute of Technical Disclosure (public technical number 2001-). 1745, issued on March 15, 2001, Invention Association). The cellulose described on pages 7 to 8 can be used, and the cellulose acylate film of the present invention is not particularly limited.

[Additive]
In the present invention, examples of the additive that can be used in the cellulose acylate solution include a plasticizer, an ultraviolet absorber, a deterioration preventing agent, an Re developing agent, an Rth reducing agent, a wavelength dispersion adjusting agent, fine particles, and a peeling accelerator. And infrared absorbers. In the present invention, it is preferable to use a Re enhancer. Moreover, it is preferable to use 1 or more types of a plasticizer, a ultraviolet absorber, and a peeling accelerator.
They may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, a UV absorber having a melting point of 20 ° C. or lower and a UV absorber having a melting point of 20 ° C. or higher can be used in combination, or a plasticizer can be used in the same manner, as described in, for example, JP-A-2001-151901. ing.
As the ultraviolet absorber, any type can be selected according to the purpose, and a salicylic acid ester-based, benzophenone-based, benzotriazole-based, benzoate-based, cyanoacrylate-based, nickel complex-based absorber or the like is used. Preferred are benzophenone series, benzotriazole series, and salicylic acid ester series. Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4-methoxybenzophenone, 2, 2′-di-hydroxy-4,4′-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4- (2-hydroxy-3- And methacryloxy) propoxybenzophenone. As the benzotriazole ultraviolet absorber, 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-butylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5 And chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, and the like. Examples of salicylic acid esters include phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate. Among these exemplified ultraviolet absorbers, in particular, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4,4′-methoxybenzophenone, 2 (2′-hydroxy-3′-tert-butyl- 5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole is particularly preferred.

  As the ultraviolet absorber, it is preferable to use a combination of a plurality of absorbers having different absorption wavelengths because a high blocking effect can be obtained in a wide wavelength range. From the viewpoint of preventing deterioration of the liquid crystal, the ultraviolet absorbent for liquid crystal is preferably excellent in the ability to absorb ultraviolet light having a wavelength of 370 nm or less, and has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Particularly preferred ultraviolet absorbers are the benzotriazole compounds, benzophenone compounds, and salicylic acid ester compounds mentioned above. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to cellulose acylate is small.

  As for the UV absorber, JP-A-60-235852, JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, JP-A-6-107854. 118233, 6-148430, 7-11056, 7-11055, 7-11056, 8-29619, 8-239509, and JP-A-2000-204173. The described compounds can also be used.

The addition amount of the ultraviolet absorber is preferably 0.001 to 5% by mass, preferably 0.01 to 1% by mass with respect to the cellulose acylate from the viewpoint of the addition effect and suppressing the ultraviolet absorber from bleeding out to the film surface. Is more preferable.

  Further, the ultraviolet absorber may be added simultaneously with the dissolution of cellulose acylate, or may be added to the dope after dissolution. In particular, a mode in which an ultraviolet absorbent solution is added to the dope immediately before casting using a static mixer or the like is preferable because the spectral absorption characteristics can be easily adjusted.

  The deterioration preventing agent prevents cellulose triacetate and the like from deteriorating and decomposing. Examples of the deterioration preventing agent include butylamine, hindered amine compounds (JP-A-8-325537), guanidine compounds (JP-A-5-271471), benzotriazole-based UV absorbers (JP-A-6-235819), and benzophenone-based compounds. There are compounds such as UV absorbers (JP-A-6-118233).

  The plasticizer is preferably a phosphate ester or a carboxylic acid ester. Specific examples of the plasticizer include triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, dimethyl phthalate (DMP), Diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP), diethyl hexyl phthalate (DEHP), O-acetyl citrate triethyl (OACTE), O-acetyl citrate tributyl (OACTB) , Acetyl triethyl citrate, acetyl tributyl citrate, butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate, triacetin Tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate may be preferably mentioned. Further, preferred plasticizers include (di) pentaerythritol esters, glycerol esters, and diglycerol esters.

  Examples of the peeling accelerator include citric acid ethyl esters. Furthermore, infrared absorbers are described in, for example, JP-A-2001-194522.

These additives may be added at any stage in the dope production process, but may be added by adding a process of adding an additive as the final preparation process of the dope preparation process. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902 and the like, but these are conventionally known techniques.
Furthermore, about an additive, what is described in detail after 16 pages of invention association public technical bulletins (public technical number 2001-1745, March 15, 2001 issue, invention association) can be used suitably.

[Re expression agent]
In the present invention, it is preferable to use a Re enhancer in order to develop a preferable retardation value.
Examples of the Re enhancer that can be used in the present invention include those composed of rod-like or discotic compounds.
As the rod-like or discotic compound, a compound having at least two aromatic rings can be used.
The addition amount of the Re developing agent composed of the rod-shaped compound is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. preferable.
The disc-shaped Re enhancer is preferably used in the range of 0.05 to 20 parts by weight, and in the range of 0.1 to 10 parts by weight, with respect to 100 parts by weight of the polymer component containing the cellulose acylate. More preferably, it is more preferably used in the range of 0.2 to 5 parts by mass, and most preferably in the range of 0.5 to 2 parts by mass.
Two or more types of Re developing agents may be used in combination.
The Re enhancer comprising a rod-like or discotic compound preferably has maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

The discotic compound will be described. As the discotic compound, a compound having at least two aromatic rings can be used.
In the present specification, the “aromatic ring” includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring.
The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).
The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
As the aromatic ring, benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferable, In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, a compound disclosed in JP 2001-166144 A is preferably used as the discotic compound.

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

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

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

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

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

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

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

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

  In the present invention, in addition to the aforementioned discotic compound, a rod-shaped compound having a linear molecular structure can also be preferably used. The linear molecular structure means that the molecular structure of the rod-like compound is linear in the most thermodynamically stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, molecular orbital calculation can be performed using molecular orbital calculation software (for example, WinMOPAC2000, manufactured by Fujitsu Limited) to obtain a molecular structure that minimizes the heat of formation of a compound. The molecular structure being linear means that in the thermodynamically most stable structure obtained by calculation as described above, the angle of the main chain constituting the molecular structure is 140 degrees or more.

As the rod-shaped compound, those having at least two aromatic rings are preferable, and as the rod-shaped compound having at least two aromatic rings, a compound represented by the following general formula (1) is preferable.
Formula (1): Ar ¹ -L ¹ -Ar ²
In the general formula (1), Ar ¹ and Ar ² are each independently an aromatic group.
In the present specification, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.
An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. The heterocycle of the aromatic heterocyclic group is generally unsaturated. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As a hetero atom, a nitrogen atom, an oxygen atom or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.
As the aromatic ring of the aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring are preferable, and a benzene ring is particularly preferable. .

  Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group (for example, methyl Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (for example, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group) ), Sulfamoyl group, alkylsulfamoyl group (for example, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido group, alkylureido group (for example, N -Methylureido group, N, N-dimethylureido group, N, N, N'-trimethylureido group), An alkyl group (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, tert-amyl group, cyclohexyl group, cyclopentyl group), alkenyl group (for example, , Vinyl group, allyl group, hexenyl group), alkynyl group (for example, ethynyl group, butynyl group), acyl group (for example, formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (for example, acetoxy group) Group, butyryloxy group, hexanoyloxy group, lauryloxy group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, heptyloxy group, octyloxy group), aryloxy group (for example, , Phenoxy group), alkoxycarbonyl group For example, methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (for example, phenoxycarbonyl group), alkoxycarbonylamino group (for example, butoxycarbonyl group) Amino group, hexyloxycarbonylamino group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group), arylthio group (for example, phenylthio group), alkylsulfonyl group ( For example, methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfo group Le group), an amido group (e.g., acetamido group, butylamide group, hexylamide group, laurylamide group) and a non-aromatic Hajime Tamaki (e.g., morpholyl group, include pyrazinyl group).

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom, a cyano group, a carboxyl group, a hydroxyl group, an amino group, an alkyl-substituted amino group, an acyl group, an acyloxy group, an amide group, an alkoxycarbonyl group, Alkoxy groups, alkylthio groups and alkyl groups are preferred.
The alkyl part and alkyl group of the alkylamino group, alkoxycarbonyl group, alkoxy group and alkylthio group may further have a substituent. Examples of the alkyl moiety and the substituent of the alkyl group include halogen atom, hydroxyl, carboxyl, cyano, amino, alkylamino group, nitro, sulfo, carbamoyl, alkylcarbamoyl group, sulfamoyl, alkylsulfamoyl group, ureido, alkylureido Group, alkenyl group, alkynyl group, acyl group, acyloxy group, acylamino group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkylsulfonyl group, amide group And non-aromatic heterocyclic groups. As the substituent for the alkyl moiety and the alkyl group, a halogen atom, hydroxyl, amino, alkylamino group, acyl group, acyloxy group, acylamino group, alkoxycarbonyl group and alkoxy group are preferable.

In the general formula (1), L ¹ is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, —O—, —CO— and a combination thereof.
The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As the chain alkylene group, a linear alkylene group is more preferable than a branched alkylene group.
The number of carbon atoms of the alkylene group is preferably 1-20, more preferably 1-15, still more preferably 1-10, still more preferably 1-8, and most preferably 1-6. It is.

The alkenylene group and the alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably have a linear structure rather than a branched chain structure.
The alkenylene group and the alkynylene group preferably have 2 to 10 carbon atoms, more preferably 2 to 8, more preferably 2 to 6, still more preferably 2 to 4, and most preferably 2. (Vinylene or ethynylene).
The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.
In the molecular structure of the general formula (1), the angle formed by Ar ¹ and Ar ² across L ¹ is preferably 140 degrees or more.

As the rod-like compound, a compound represented by the following formula (2) is more preferable.
Formula ^{(2): Ar 1 -L 2} -X-L 3 -Ar 2
In the general formula (2), Ar ¹ and Ar ² are each independently an aromatic group. The definition and examples of the aromatic group are the same as those of Ar ¹ and Ar ^{2 in} the general formula (1).

In the general formula (2), L ² and L ³ are each independently a divalent linking group selected from an alkylene group, —O—, —CO— and a group consisting of a combination thereof.
The alkylene group preferably has a chain structure rather than a cyclic structure, and more preferably has a linear structure rather than a branched chain structure.
The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and 1 or 2 (methylene or Most preferred is ethylene).
L ² and L ³ are particularly preferably —O—CO— or —CO—O—.

In the general formula (2), X is 1,4-cyclohexylene, vinylene or ethynylene.
Specific examples of the compound represented by the general formula (1) or (2) are shown below.

  Specific examples (1) to (34), (41), and (42) have two asymmetric carbon atoms at the 1-position and the 4-position of the cyclohexane ring. However, since the specific examples (1), (4) to (34), (41), and (42) have a symmetrical meso type molecular structure, there are no optical isomers (optical activity), and geometric isomers (trans Type and cis type). The trans type (1-trans) and cis type (1-cis) of specific example (1) are shown below.

As described above, the rod-like compound preferably has a linear molecular structure. Therefore, the trans type is preferable to the cis type.
Specific examples (2) and (3) have optical isomers (a total of four isomers) in addition to geometric isomers. As for geometric isomers, the trans type is similarly preferable to the cis type. The optical isomer is not particularly superior or inferior, and may be D, L, or a racemate.
In specific examples (43) to (45), the central vinylene bond includes a trans type and a cis type. For the same reason as above, the trans type is preferable to the cis type.

  A compound represented by the following general formula (3) is also preferable.

General formula (3)

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and R ¹ , R ² , R ³ , R ⁴ and R ⁵ each represents an electron donating group, wherein R ⁸ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. Group, aryl group having 6 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryloxy group having 6 to 12 carbon atoms, alkoxycarbonyl group having 2 to 12 carbon atoms, acylamino group having 2 to 12 carbon atoms, cyano Represents a group or a halogen atom.)

Two or more rod-shaped compounds whose maximum absorption wavelength (λmax) is shorter than 250 nm in the ultraviolet absorption spectrum of the solution may be used in combination.
The rod-like compound can be synthesized by a method described in the literature. References include Mol. Cryst. Liq. Cryst., 53, 229 (1979), 89, 93 (1982), 145, 111 (1987), 170, 43 Page (1989), J. Am. Chem. Soc., 113, 1349 (1991), 118, 5346 (1996), 92, 1582 (1970), J. Org Chem., 40, 420 (1975), Tetrahedron, 48, 16, 3437 (1992).

  The retardation increasing agent may be an inorganic compound or may have a negative birefringence. For example, strontium carbonate can be used.

<Rth reducing agent>
In order to reduce Rth, compounds represented by the following general formulas (13) to (19) may be added.

[Wherein, R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represents a hydrogen atom, an alkyl group, or an aryl group. The total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more, and each of the alkyl group and aryl group may have a substituent. ]

The compound of the general formula (13) will be described.
In the general formula (13), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Moreover, it is particularly preferable that the total number of carbon atoms of R ¹ , R ² and R ³ is 10 or more. R ¹ , R ² and R ³ may be substituted, and the substituent is preferably a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group and a sulfonamide group, and an alkyl group, an aryl group, an alkoxy group, A sulfone group and a sulfonamide group are particularly preferred. Further, the alkyl group may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, and more preferably 6 to 20 (For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclo Octyl, 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 group, biphenyl group, terphenyl group, naphthyl group, binaphthyl group, triphenylphenyl group) are particularly preferable. Preferred examples of the compound represented by the general formula (13) are shown below, but the present invention is not limited to these specific examples.

[Wherein, R ⁴ and R ⁵ each independently represents an alkyl group or an aryl group. The total number of carbon atoms of R ⁴ and R ⁵ is 10 or more, and each of the alkyl group and aryl group may have a substituent. ]

[Wherein, R ¹ , R ² and R ³ each independently represents a hydrogen atom or an alkyl group. X is one or more groups selected from a single bond, —O—, —CO—, —NR ⁴ —, an alkylene group or an arylene group (R ⁴ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group). Represents a divalent linking group formed from Y represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group.

(Wherein Q ¹ , Q ² and Q ³ each independently represents a 5- to 6-membered ring. X represents B, C—R (R represents a hydrogen atom or a substituent), N, P or P═. Represents O)

(Wherein X ² represents B, C—R (R represents a hydrogen atom or a substituent) or N. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ³¹ , R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represent a hydrogen atom or a substituent.

［式中、Ｒ¹はアルキル基またはアリール基を表し、Ｒ²およびＲ³はそれぞれ独立に水素原子、アルキル基またはアリール基を表す。また、アルキル基およびアリール基は置換基を有していてもよい。］

[Wherein, R ¹ represents an alkyl group or an aryl group, and R ² and R ³ each independently represents a hydrogen atom, an alkyl group or an aryl group. Moreover, the alkyl group and the aryl group may have a substituent. ]

Preferred as the general formula (18) is a compound represented by the following general formula (19).

In the general formula (19), R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group or an aryl 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. As the cyclic alkyl group, a cyclohexyl group is particularly preferable. The aryl group preferably has 6 to 36 carbon atoms, and more preferably 6 to 24 carbon atoms.

  The above alkyl group and aryl group may have a substituent, such as a halogen atom (for example, chlorine, bromine, fluorine and iodine), an alkyl group, an aryl group, an alkoxy group, an aryloxy group, acyl Group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, sulfonylamino group, hydroxy group, cyano group, amino group and acylamino group, more preferably halogen atom, alkyl group, aryl group, alkoxy group, aryloxy group A sulfonylamino group and an acylamino group, particularly preferably an alkyl group, an aryl group, a sulfonylamino group and an acylamino group. Although the preferable example of a compound represented by General formula (18), (19) is shown below, the compound which can be used by this invention is not limited to these specific examples.

[Wavelength dispersion modifier]
The compound that reduces the wavelength dispersion of the cellulose acylate film will be described. As a result of intensive studies, the inventors of the present invention have absorption in the ultraviolet region of 200 to ₄₀₀ nm, and | Re ₍₄₀₀₎ −Re ₍₇₀₀₎ | and | Rth ₍₄₀₀₎ −Rth ₍₇₀₀₎ | It has been found that the wavelength dispersion of Re and Rth of the cellulose acylate film can be adjusted by adding at least one compound to be reduced and 0.01 to 30% by mass based on the solid content of the cellulose acylate.

  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. Therefore, it is required to smooth the chromatic dispersion by increasing Re and Rth on the relatively short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance on the short wavelength side is larger than that on the long 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, as described above, by using the compound having absorption in the ultraviolet region of 200 to 400 nm and assuming that the wavelength dispersion of Re and Rth of the compound itself is large on the short wavelength side, the Re and Rth of the cellulose acylate film are used. The chromatic dispersion can be adjusted. For this purpose, the compound for adjusting the wavelength dispersion is required to be sufficiently homogeneously 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 even more preferably 240 to 390 nm.

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

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

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

(Compound addition amount)
The 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, and It is especially preferable that it is 2-10 mass%.

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

  Specific examples of the wavelength dispersion adjusting agent preferably used in the present invention include, for example, benzotriazole compounds, benzophenone compounds, compounds containing a cyano group, oxybenzophenone compounds, salicylic acid ester compounds, nickel complex compounds, and the like. However, the compounds that can be used in the present invention are not limited thereto.

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

Formula (101) Q ¹ -Q ² -OH

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

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

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring is preferably (preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, benzene ring, naphthalene ring etc.), more preferably 6 carbon atoms. -20 aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms.) More preferred is a benzene ring.
The aromatic heterocycle is preferably an aromatic heterocycle containing a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring include, for example, thiophene ring, imidazole ring, pyrazole ring, pyridine ring, pyrazine ring, pyridazine ring, triazole ring, triazine ring, indole ring, indazole ring, purine ring, thiazoline ring, thiazole ring, thiadiazole. Ring, oxazoline ring, oxazole ring, oxadiazole ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine ring, phenanthroline ring, phenazine ring, tetrazole ring, benz Examples include an imidazole ring, a benzoxazole ring, a benzthiazole ring, a benzotriazole ring, and a tetrazaindene ring. The aromatic hetero ring is preferably a pyridine ring, a triazine ring or a quinoline ring.
The aromatic ring represented by Q ² is preferably an aromatic hydrocarbon ring, more preferably a naphthalene ring or a benzene ring, and particularly preferably a benzene ring. Q ² may further have a substituent, and the substituent T described later is preferable.
Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, and tert-butyl. Group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 carbon atoms). To 12, particularly preferably 2 to 8 carbon atoms, such as vinyl group, allyl group, 2-butenyl group, and 3-pentenyl group), alkynyl group (preferably 2 to 20 carbon atoms, more preferably Has 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include a propargyl group and a 3-pentynyl group.), Aryl (Preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, and examples thereof include a phenyl group, a p-methylphenyl group, and a naphthyl group). An unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably 0 to 6 carbon atoms; for example, an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a diamino group; Benzylamino group, etc.), alkoxy groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy group, ethoxy group, butoxy group. An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms). , For example, phenyloxy group, 2-naphthyloxy group, etc.), acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, An acetyl group, a benzoyl group, a formyl group, a pivaloyl group, etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms, For example, a methoxycarbonyl group, an ethoxycarbonyl group, etc.), an aryloxycarbonyl group (preferably having a carbon number of 7 to 20, more preferably a carbon number of 7 to 16, particularly preferably a carbon number of 7 to 10, such as phenyl Oxycarbonyl group, etc.), acyloxy group (preferably having 2 to 20 carbon atoms, more preferably carbon It has 2 to 16 primes, particularly preferably 2 to 10 carbons, and examples thereof include an acetoxy group and a benzoyloxy group. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include an acetylamino group and a benzoylamino group), alkoxycarbonyl. An amino group (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 Has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group, and a sulfonylamino group (preferably 1 to 1 carbon atom). 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Nylamino group, benzenesulfonylamino group, etc.), sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl group, methyl A sulfamoyl group, a dimethylsulfamoyl group, a phenylsulfamoyl group, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to carbon atoms). For example, carbamoyl, methylcarbamoyl, diethylcarbamoyl group, phenylcarbamoyl group, etc.), alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 carbon atom). -12, for example, methylthio group, ethylthio group, etc. ), An arylthio group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenylthio group), a sulfonyl group (preferably having a carbon number). 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl group, tosyl group, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl group and benzenesulfinyl group), ureido group (preferably 1 to 20 carbon atoms, more preferably 1 carbon atoms). To 16, particularly preferably 1 to 12 carbon atoms, such as a ureido group, a methylureido group, and a phenylureido group). A phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include a diethylphosphoric acid amide group and a phenylphosphoric acid amide group. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom, specifically, for example, an imidazolyl group, a pyridyl group, a quinolyl group, Furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, especially Preferably, it has 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. It is), and the like. 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 as the general formula (101) is a compound represented by the following general formula (101-A).
General formula (101-A)

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

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or a substituent, and the substituent T described above applies as the substituent. it can. These substituents may be further substituted with another substituent, and the substituents may be condensed to form a ring structure.
R ¹ and R ³ are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups, alkoxy groups, aryloxy groups, hydroxy groups, and halogen atoms, more preferably hydrogen atoms. An atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom, more preferably a hydrogen atom and an alkyl group having 1 to 12 carbon atoms, particularly preferably an alkyl group having 1 to 12 carbon atoms (preferably 4 to 12 carbon atoms).

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

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

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

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

(In the formula, R ¹ , R ³ , R ⁶ and R ⁷ are each independently the same as those in formula (101-A), and the preferred ranges are also the same.)

  Specific examples of the compound represented by the general formula (101) are given below, but the compounds that can be used in the present invention are not limited to the following specific examples.

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

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

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

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

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

  Examples of the substituent T include those described above.

Preferred as the general formula (102) is a compound represented by the following general formula (102-A).
General formula (102-A)

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

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

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

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

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

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

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

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

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

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

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

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

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

The aromatic ring represented by Q ¹ and Q ² is preferably an aromatic hydrocarbon ring, and more preferably a benzene ring.
Q ¹ and Q ² may further have a substituent, and the above-described substituent T is preferable.

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

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

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

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. X ¹ and X ² Are synonymous with those in formula (20), and the preferred range is also the same.)

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

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

R ³ and R ⁸ are preferably hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, substituted or unsubstituted amino groups, alkoxy groups, aryloxy groups, hydroxy groups, halogen atoms, more preferably hydrogen atoms. , An alkyl group having 1 to 20 carbon atoms, an amino group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, and a hydroxy group, more preferably a hydrogen atom and a carbon number It is a C1-C12 alkyl group and a C1-C12 alkoxy group, Especially preferably, it is a hydrogen atom.

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

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

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

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

(In formula, R < ³ > and R <^8> are respectively independently synonymous with those in General formula (103-A), and its preferable range is also the same. R < ²¹ > represents a C1-C20 alkyl group. )

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

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

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

  Specific examples of the compound represented by the general formula (103) are given below, but the compounds that can be used in the present invention are not limited to the following specific examples.

[Matting agent fine particles]
It is preferable to add fine particles as a matting agent to the cellulose acylate film of the present invention. The fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silica Mention may be made of magnesium and calcium phosphates. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / liter or more. Those having an average primary particle size as small as 5 to 16 nm are more preferred because they can reduce the haze of the film. The apparent specific gravity is preferably 90 to 200 g / liter, more preferably 100 to 200 g / liter. A higher apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.
The amount of silicon dioxide fine particles used is preferably 0.01 to 0.3 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate.

These fine particles usually form secondary particles having an average particle size of 0.1 to 3.0 μm, and these fine particles exist in the film as aggregates of primary particles, and 0.1 to 0.1 μm on the film surface. An unevenness of 3.0 μm is formed. The secondary average particle size is preferably 0.2 μm to 1.5 μm, more preferably 0.4 μm to 1.2 μm, and most preferably 0.6 μm to 1.1 μm. When the secondary average particle size is in the above range, the effect of preventing squeaking is sufficiently exhibited and the haze is small.
For the primary and secondary particle sizes, the particles in the film are observed with a scanning electron microscope, and the diameter of a circle circumscribing the particles is defined as the particle size. Also, 200 particles are observed at different locations, and the average value is taken as the average particle size.

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

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

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

[Dope preparation]
Next, preparation of a cellulose acylate solution (dope) will be described. The method for dissolving the cellulose acylate is not particularly limited, and may be room temperature, or a cooling dissolution method or a high-temperature dissolution method, or a combination thereof. Regarding these, for example, JP-A-5-163301, JP-A-61-106628, JP-A-58-127737, JP-A-9-95544, JP-A-10-95854, JP-A-10-45950, JP 2000-53784, JP 11-322946, JP 11-322947, JP 2-276830, JP 2000-273239, JP 11-71463, JP 04-259511, Special JP-A-2000-273184, JP-A-11-323017, JP-A-11-302388, etc. describe methods for preparing a cellulose acylate solution.
The above-described method for dissolving cellulose acylate in an organic solvent is applicable to the present invention as long as it is within the scope of the present invention. The details of these methods, particularly for non-chlorine solvent systems, are described in detail on pages 22-25 of the Japan Institute of Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Institute of Invention). Will be implemented. Further, the cellulose acylate dope solution of the present invention is usually subjected to solution concentration and filtration, and similarly, the Japan Institute of Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Invention Association), page 25. Are described in detail. In addition, when it melt | dissolves at high temperature, it is the case where it is more than the boiling point of the organic solvent to be used, and in that case, it uses in a pressurized state.

  It is preferable that the cellulose acylate solution has a viscosity and a dynamic storage elastic modulus within the ranges described below because it is easy to cast. 1 mL of the sample solution is measured with a rheometer (CLS 500) using a Steel Cone having a diameter of 4 cm / 2 ° (both manufactured by TA Instruments). Measurement conditions were measured at Oscillation Step / Temperature Ramp, varying from 40 ° C to -10 ° C at 2 ° C / min, and static non-Newtonian viscosity n * (Pa · s) at 40 ° C and storage at -5 ° C Obtain the elastic modulus G '(Pa). The sample solution is preliminarily kept at the measurement start temperature until the liquid temperature becomes constant, and then the measurement is started. In the present invention, the viscosity at 40 ° C. is 1 to 400 Pa · s, the dynamic storage elastic modulus at 15 ° C. is preferably 500 Pa or more, and more preferably the viscosity at 40 ° C. is 10 to 200 Pa · s. And the dynamic storage elastic modulus in 15 degreeC is 100-1 million. Furthermore, it is preferable that the dynamic storage elastic modulus at a low temperature is large. For example, when the casting support is −5 ° C., the dynamic storage elastic modulus is preferably 10,000 to 1,000,000 Pa at −5 ° C. When the body is at −50 ° C., the dynamic storage elastic modulus at −50 ° C. is preferably 10,000 to 5 million Pa.

  In the present invention, since the above-mentioned specific cellulose acylate is used, it is characterized in that a high concentration dope is obtained, and a cellulose acylate having a high concentration and excellent stability without relying on a means of concentration. A solution is obtained. Furthermore, in order to make it easy to melt | dissolve, you may melt | dissolve in a low density | concentration and may concentrate using a concentration means. The concentration method is not particularly limited. For example, the low-concentration solution is guided between the cylindrical body and the rotation trajectory of the outer periphery of the rotating blade rotating in the circumferential direction, and the temperature between the solution and the solution. A method of obtaining a high-concentration solution while evaporating the solvent by giving a difference (for example, JP-A-4-259511), a heated low-concentration solution is blown into the container from the nozzle, and the solution is applied from the nozzle to the inner wall of the container In which the solvent is flash evaporated and the solvent vapor is withdrawn from the container and the concentrated solution is withdrawn from the bottom of the container (eg, US Pat. No. 2,541,012, US Pat. No. 2,858,229, US Pat. No. 4,414,341, US Pat. No. 4,504,355, etc.).

Prior to casting, it is preferable to filter off foreign matters such as undissolved matter, dust, and impurities using a suitable filter medium such as a wire mesh or flannel. For the filtration of the cellulose acylate solution, it is preferable to use a filter having an absolute filtration accuracy of 0.1 to 100 μm, and it is more preferable to use a filter having an absolute filtration accuracy of 0.5 to 25 μm. The thickness of the filter is preferably 0.1 to 10 mm, and more preferably 0.2 to 2 mm. In that case, the filtration pressure is 1.6 MPa. The following is preferable, more preferably 1.2 MPa or less, further 1.0 MPa or less, and particularly preferably 0.2 MPa or less. As the filter medium, conventionally known materials such as glass fibers, cellulose fibers, filter paper, fluororesins such as tetrafluoroethylene resin can be preferably used, and ceramics, metals and the like are particularly preferably used. The viscosity of the cellulose acylate solution immediately before film formation may be in a range that can be cast during film formation, and is usually prepared in a range of 10 Pa · s to 2000 Pa · s, preferably 30 Pa · s to 1000 Pa. · S is more preferable, and 40 Pa · s to 500 Pa · s is more preferable. The temperature at this time is not particularly limited as long as it is a temperature at the time of casting, but is preferably −5 to + 70 ° C., more preferably −5 to + 55 ° C.

[Film formation]
The cellulose acylate film of the present invention can be obtained by forming a film using the cellulose acylate solution. As the film forming method and equipment, 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 from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation. The dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations, and the dope is run endlessly from the die (slit) of the pressure die. The dry-dried dope film (also referred to as web) is peeled off from the metal support at a peeling point that is uniformly cast on the metal support and substantially rounds the metal support. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder. The combination of the tenter and the roll group dryer varies depending on the purpose. In the solution casting film forming method used for the functional protective film for electronic displays, in addition to the solution casting film forming apparatus, surface processing on films such as an undercoat layer, an antistatic layer, an antihalation layer, a protective layer, etc. Therefore, a coating device is often added. Although each manufacturing process is described briefly below, it is not limited to these.

First, when the cellulose acylate solution (dope) prepared is produced by a solvent casting method, a dope is cast on a drum or a band, and a solvent is evaporated to form a film. It is preferable to adjust the concentration of the dope before casting so that the solid content is 5 to 40% by mass. The surface of the drum or band is preferably finished in a mirror state. The dope is preferably cast on a drum or band having a surface temperature of 30 ° C. or lower, and particularly preferably a metal support temperature of −10 to 20 ° C. Further, JP 2000-301555, JP 2000-301558, JP 07-032391, JP 03-193316, JP 05-086212, JP 62-037113, JP 02-276607. The methods described in JP-A Nos. 55-014201, 02-111511, and 02-208650 can be used in the present invention.
The film forming speed is preferably 5 to 300 m / min, more preferably 20 to 100 m / min, and most preferably 40 to 80 m / min. The film forming speed referred to in this specification means a casting speed when forming a film by a casting method.

[Multilayer casting]
The cellulose acylate solution may be cast as a single layer liquid on a smooth band or drum as a metal support, or a plurality of cellulose acylate liquids of two or more layers may be cast. When casting a plurality of cellulose acylate solutions, produce a film while casting and laminating a solution containing cellulose acylate from a plurality of casting openings provided at intervals in the traveling direction of the metal support. For example, the methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be applied. A film may also be formed by casting a cellulose acylate solution from two casting ports. For example, Japanese Patent Publication Nos. 60-27562, 61-94724, 61-947245, 61-947245, This can be carried out by the methods described in JP-A Nos. 61-104813, 61-158413, and 6-134933. Further, a cellulose acylate film in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded. A casting method may be used. Furthermore, it is also a preferred embodiment that the outer solution described in JP-A-61-94724 and JP-A-61-94725 contains a larger amount of an alcohol component which is a poor solvent than the inner solution. Alternatively, by using two casting ports, peeling the film formed on the metal support by the first casting port, and performing the second casting on the side that was in contact with the metal support surface, A film may be prepared, for example, a method described in Japanese Patent Publication No. 44-20235. The cellulose acylate solutions to be cast may be the same solution or different cellulose acylate solutions, and are not particularly limited. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Further, the cellulose acylate solution may be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing film).

  In the conventional single-layer liquid, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution in order to obtain the required film thickness. In many cases, this causes a problem such as a fault or flatness. As a solution to this, by casting a plurality of cellulose acylate solutions from a casting port, a highly viscous solution can be extruded onto a metal support at the same time. Not only can it be produced, but also a concentrated cellulose acylate solution can be used to reduce the drying load and increase the film production speed. In the case of co-casting, the inner and outer thicknesses are not particularly limited, but preferably the outer side is preferably 1 to 50% of the total film thickness, and more preferably 2 to 30%. Here, in the case of co-casting with three or more layers, the total thickness of the layer in contact with the metal support and the layer in contact with the air side is defined as the outer thickness. In the case of co-casting, a cellulose acylate film having a laminated structure can be produced by co-casting cellulose acylate solutions having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent. For example, a cellulose acylate film having a structure of skin layer / core layer / skin layer can be produced. For example, the matting agent can be contained in the skin layer in a large amount or only in the skin layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer. It is also possible to change the type of plasticizer and ultraviolet absorber between the core layer and the skin layer. For example, the skin layer contains at least one of a low-volatile plasticizer and an ultraviolet absorber, and the core layer is plastic. It is also possible to add an excellent plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. Moreover, it is also a preferable aspect to contain a peeling accelerator only in the skin layer on the metal support side. It is also preferable to add more alcohol, which is a poor solvent, to the skin layer than the core layer in order to cool the metal support by the cooling drum method to gel the solution. The Tg of the skin layer and the core layer may be different, and the Tg of the core layer is preferably lower than the Tg of the skin layer. Further, the viscosity of the solution containing cellulose acylate during casting may be different between the skin layer and the core layer, and the viscosity of the skin layer is preferably smaller than the viscosity of the core layer. It may be smaller than the viscosity.

[Casting]
As a solution casting method, a method in which the prepared dope is uniformly extruded from a pressure die onto a metal support, and a method using a doctor blade in which the dope once cast on the metal support is adjusted with a blade is used. Alternatively, there is a method using a reverse roll coater that adjusts with a reverse rotating roll, but a method using a pressure die is preferable. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods listed here, it can be carried out by various methods for casting a cellulose triacetate solution known in the art, and by setting each condition in consideration of differences in the boiling point of the solvent used, etc. The same effects as described in the above publication can be obtained. The endlessly running metal support used for producing the cellulose acylate film of the present invention includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt whose surface is mirror-finished by polishing (referred to as a band). May be used). One or two or more pressure dies used for producing the cellulose acylate film of the present invention may be installed above the metal support. Preferably 1 or 2 groups. When two or more are installed, the dope amount to be cast may be divided into various ratios for each die, or the dope may be fed to the dies from each of a plurality of precision quantitative gear pumps. The temperature of the cellulose acylate solution used for casting is preferably −10 to 55 ° C., more preferably 25 to 50 ° C. In that case, all of the processes may be the same, or may be different at various points in the process. If they are different, it may be a desired temperature just before casting.

[Dry]
The drying of the dope on the metal support involved in the production of the cellulose acylate film is generally performed by applying hot air from the surface side of the metal support (drum or belt), that is, the surface of the web on the metal support, A method of applying hot air from the back of the drum or belt, contacting the temperature-controlled liquid from the back of the belt or drum opposite the dope casting surface, and heating the drum or belt by heat transfer to control the surface temperature Although there is a heat transfer method, the back surface liquid heat transfer method is preferable. The surface temperature of the metal support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the metal support, the temperature should be set to 1 to 10 ° C. lower than the boiling point of the lowest boiling solvent. Is preferred. This is not the case when the casting dope is cooled and peeled off without drying.

[Stretching treatment]
In the cellulose acylate film of the present invention, the retardation can be adjusted by a stretching treatment. Furthermore, there is also a method of positively stretching in the width direction. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4-284111, JP-A-4-298310, and JP-A-11 -48271, and the like. This stretches the produced film in order to increase the in-plane retardation value of the cellulose acylate film.
The film is stretched at room temperature or under heating conditions. The heating temperature is preferably ± 20 ° C. sandwiching the glass transition temperature of the film. If the film is stretched at a temperature extremely lower than the glass transition temperature, the film tends to break and cannot exhibit desired optical properties. In addition, when stretching at a temperature extremely higher than the glass transition temperature, it is not possible to fix the orientation by relaxing with the heat during stretching before the molecularly oriented material by stretching is heat-set. Becomes worse.
The stretching of the film may be uniaxial stretching (fixed width, free width) only in the longitudinal or lateral direction, or simultaneous or sequential biaxial stretching. Stretching is performed by 10 to 200%. The stretching is preferably 12 to 100%, particularly preferably 15 to 80%.
When used as a retardation film for a liquid crystal display device, it is necessary that the cellulose acylate film has a direction with a large refractive index in a direction perpendicular to the absorption axis of the polarizer. Therefore, it is preferable that the refractive index in the width direction of the optical film is larger than the refractive index in the length direction.
In addition, the stretching process may be performed in the middle of the film forming process, or the raw film that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount (wet ratio), and the residual solvent amount (wet ratio) (residual solvent amount / (residual solvent amount + solid content amount)) is 2 to 50%. It can be preferably stretched.

The film thickness of the cellulose acylate film of the present invention obtained after drying varies depending on the purpose of use and is usually preferably in the range of 5 to 500 μm, more preferably in the range of 40 to 200 μm, still more preferably in the range of 40 to 180 μm. Particularly preferably, it is in the range of 40 to 150 μm, particularly preferably 40 to 130 μm. Moreover, it is preferable that it is 40-120 micrometers especially for liquid crystal display devices as an object for optics.
Since the absolute value of the retardation is proportional to the film thickness, the optical characteristics of the film can be adjusted by adjusting the film thickness. Moreover, since the water vapor transmission rate decreases in inverse proportion to the film thickness, increasing the film thickness reduces the water vapor transmission rate and makes it difficult for water to pass through. This is advantageous in a polarizing plate durability test for 500 hours at 60 ° C. and 90% relative humidity.
The thickness of the film may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like. The width of the cellulose acylate film obtained as described above is preferably 0.5 to 3 m, more preferably 0.6 to 2.5 m, still more preferably 0.8 to 2.2 m, and particularly preferably 1. 0 to 2.2 m. If the width is too thin, the production efficiency tends to be low, and it is difficult to apply to large liquid crystal display devices. The length is preferably 100 to 10000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, knurling is preferably applied to at least one end, the width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. This may be a single push or a double push.

[Optical properties of cellulose acylate film]
The in-plane retardation value Re and thickness direction retardation value Rth of the cellulose acylate film of the present invention satisfy the following formulas (XI) and (XII), respectively. This is preferable because the viewing angle of a liquid crystal display device, particularly an IPS mode liquid crystal display device, can be widened.
Formula (XI): 50 nm <Re ₍₅₉₀₎ <400 nm
Formula (XII): −200 nm ≦ Rth ₍₅₉₀₎ ≦ 50 nm
[Wherein, Re ₍ λ ₎ is the in-plane retardation value (unit: nm) at the wavelength λnm, and Rth ₍ λ ₎ is the retardation value (unit: nm) in the thickness direction at the wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film. That's it. ]
The cellulose acylate film of the present invention more preferably satisfies the following mathematical formula.
Formula (XIII): 110 nm ≦ Re ₍₅₉₀₎ ≦ 300 nm
Formula (XIV): −100 nm ≦ Rth ₍₅₉₀₎ ≦ 20 nm
The cellulose acylate film of the present invention more preferably satisfies the following mathematical formula.
Formula (XV): 150 nm ≦ Re ₍₅₉₀₎ ≦ 300 nm
Formula (XVI): −50 nm ≦ Rth ₍₅₉₀₎ ≦ 5 nm
Moreover, the absolute value of the Nz value represented by the following mathematical formula is preferably 10 or less, more preferably 1 or less, and most preferably 0.7 or less.
Formula (A): Nz = Rth ₍₅₉₀₎ / Re ₍₅₉₀₎ +0.5
In particular, when used in an IPS liquid crystal display device, the cellulose acylate film of the present invention preferably has Re of 200 to 330 nm and | Nz | of 0.3 to 0.7, more preferably Re of 220 to 300 nm. , | Nz | is 0.4 to 0.6, more preferably Re is 250 to 290 nm, and | Nz | is 0.4 to 0.6.
In addition, by producing an optical compensation sheet in which the cellulose acylate film of the present invention having specific optical characteristics and another optical compensation layer are laminated, it becomes possible to realize various optical characteristics and freedom of optical design. The degree can be increased.

  Further, the cellulose acylate film of the present invention has a difference ΔRe = Re (10% RH) −Re (80% RH) between the Re value at 25 ° C./relative humidity 10% and the Re value at 25 ° C./relative humidity 80%. Is 0 to 50 nm, and the difference ΔRth = Rth (10% RH) −Rth (80% RH) between the Rth value at 25 ° C. and relative humidity of 10% and the Rth value at 25 ° C. and relative humidity of 80% is 0 It is preferable that the thickness is ˜30 nm in order to reduce the color change with time of the liquid crystal display device.

Regarding the film thickness distribution in the width direction of Re, 10 samples of 2 cm (width direction) × 3 cm (width width orthogonal direction) are taken at equal intervals sequentially from the position 5 cm inside from the film edge. Then, it can be evaluated by measuring the thickness. The film thickness of each test piece (2 cm × 3 cm) can be determined by measuring a total of nine points in the longitudinal and lateral directions in the plane of the film.
When the film thickness distribution R is defined as R (%) = (Rmax−Rmin) / Rave × 100 when the maximum value, minimum value, and average value of the film thickness in the width direction are Rmax, Rmin, and Rave, respectively. R is preferably adjusted to 0 to 8%, more preferably adjusted to 0 to 7.8%, and further preferably adjusted to 0 to 7.6%. Since Re and Rth are values proportional to the film thickness, the smaller the film thickness distribution in the width direction of the film thickness, the smaller the variation in Re (590) and Rth (590).
The distribution of Re (590) and Rth (590) is caused by the film thickness variation or due to stretching unevenness, drying unevenness, etc., but this Re distribution (variation) is 5% or less. The Rth distribution is preferably adjusted to 10% or less. More preferably, the Re distribution is 4.8% or less, the Rth distribution is 9.8% or less, more preferably the Re distribution is 4.6% or less, and the Rth distribution is 9.6% or less. It is preferable.
The film thickness distribution R, Re distribution, and Rth distribution described above are preferable because display unevenness is reduced when the film is used in a liquid crystal display device.

In the present invention, the optical characteristics were measured by the following method.
Re ₍ λ ₎ was measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth ₍ λ ₎ is the Re ₍ λ ₎ , a retardation value measured by making light of wavelength λnm incident from a direction inclined + 40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis, And the retardation value measured in three directions, that is, 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. Based on this, an assumed average refractive index of 1.48 and a film thickness were input and calculated. In this specification, unless otherwise specified, the retardation value is a value measured at a wavelength of 590 nm.
In the cellulose acylate film of the present invention, the color difference ΔE ^* ab before and after aging at 90 ° C. for 500 hours is preferably 0.8 or less, preferably 0.7 or less, The following is more preferable. The color difference between before and after aging at 140 ° C. for 24 hours is preferably 1.5 or less, more preferably 1.0 or less, and further preferably 0.5 or less. If the film is colored under an environmentally forced condition such as 90 ° C. for 500 hours or 140 ° C. for 24 hours, the optical compensation ability as a retardation film is lowered, which is not preferable in terms of appearance. The color difference was measured using UV3100 (manufactured by Shimadzu Corporation). The measurement was carried out by adjusting the film to 25 ° C. and 60% relative humidity for 2 hours or more, and then measuring the color of the film before aging the thermo to obtain initial values (L0 ^* , a0 ^* , b0 ^* ). Thereafter, the film alone was left in an air thermostat for a predetermined time. After a predetermined time has passed, the film is taken out of the thermostatic chamber, adjusted to 25 ° C. and 60% relative humidity for 2 hours, then subjected to color measurement, and the values after thermostating (L1 ^* , a1 ^* , b1 ^* ) are obtained. It was. From these, the color difference ΔE ^* ab = ((L0 ^* −L1 ^* ) ² + (a0 ^* −a1 ^* ) ² + (b0 ^* −b1 ^* ) ² ) ^1/2 was obtained.

In the cellulose acylate film of the present invention, the equilibrium water content at 25 ° C. and 80% relative humidity is preferably 5.0% or less, more preferably 4.0% or less, and 3.2%. The following is more preferable, and it is preferable for reducing the change in color of the liquid crystal display device over time.
The moisture content is measured by measuring the cellulose acylate film sample 7 mm × 35 mm of the present invention by the Karl Fischer method using a moisture measuring device and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). . It is calculated by dividing the amount of water (g) by the sample mass (g).
Further, the cellulose acylate film of the present invention, 60 ° C. · 95% RH, a moisture permeability (film thickness 80μm equivalent) of 24 hours, a 400 g / m ² · 24 hours ~1800g / m ² · 24 hours However, it is preferable in order to reduce the color change with time of the liquid crystal display device.
If the film thickness of the cellulose acylate film is thick, the moisture permeability becomes small, and if the film thickness is thin, the moisture permeability becomes large. The measured moisture permeability is converted with a reference film thickness of 80 μm. The converted value of moisture permeability is calculated by “80 μm converted moisture permeability = actually measured moisture permeability × actually measured film thickness μm / 80 μm”.
The measurement method of moisture permeability 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) The method described in can be applied.

  The glass transition temperature was measured by adjusting a viscoelasticity measuring apparatus (Vibron: DVA-) after conditioning the cellulose acylate film sample (unstretched) 5 mm × 30 mm of the present invention at 25 ° C. and 60% relative humidity for 2 hours or more. 225 (manufactured by IT Measurement Control Co., Ltd.) with a distance between grips of 20 mm, a temperature increase rate of 2 ° C./min, a measurement temperature range of 30 ° C. to 200 ° C., and a frequency of 1 Hz. When a temperature (° C.) is taken on the linear axis on the horizontal axis, a straight line 1 is drawn in the solid region to draw a sharp decrease in the storage elastic modulus seen when the storage elastic modulus transitions from the solid region to the glass transition region. The intersection of the straight line 1 and the straight line 2 when the straight line 2 is drawn in the transition region is a temperature at which the storage elastic modulus suddenly decreases and the film starts to soften when the temperature rises, and the temperature starts to move to the glass transition region. ,Glass-transition temperature And g (dynamic viscoelasticity).

  The elastic modulus was measured by conditioning a 10 mm × 150 mm dry film cellulose acylate film sample of the present invention at 25 ° C. and a relative humidity of 60% for 2 hours or more, and then using a tensile tester (Strograph-R2 (manufactured by Toyo Seiki Co., Ltd.). )), The distance between chucks was 100 mm, the temperature was 25 ° C., and the stretching speed was 10 mm / min.

The cellulose acylate film of the present invention preferably has a haze of 0.01 to 2%. Here, the haze is measured as follows.
The cellulose acylate film sample 40 mm × 80 mm of the present invention is measured according to JIS K-6714 with a haze meter (HGM-2DP, Suga Test Instruments) at 25 ° C. and a relative humidity of 60%.
Moreover, it is preferable that the mass change when the cellulose acylate film of this invention is left still for 48 hours on the conditions of 80 degreeC and relative humidity 90% is 0 to 5%.
In addition, the cellulose acylate film of the present invention has a dimensional change when left for 24 hours under conditions of 60 ° C. and 95% relative humidity, and when left for 24 hours under conditions of 90 ° C. and 5% relative humidity. The dimensional change is preferably 0 to 5%.

The photoelastic coefficient of the cellulose acylate film of the present invention is preferably 50 × 10 ⁻¹³ cm ² / dyne or less in order to reduce the color change with time of the liquid crystal display device.
As a specific measurement method, a tensile stress is applied to the major axis direction of a cellulose acylate film sample 10 mm × 100 mm, and the retardation at that time is measured with an ellipsometer (M150, JASCO Corporation). The photoelastic coefficient is calculated from the amount of change in retardation with respect to.

[Polarizer]
Next, the polarizing plate of the present invention will be described.
The polarizing plate is usually composed of a polarizer and two transparent protective films disposed on both sides thereof. In the present invention, the cellulose acylate film of the present invention is used as at least one protective film. The other protective film may be the cellulose acylate film of the present invention or a normal cellulose acetate film. Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film. When the cellulose acylate film of the present invention is used as a polarizing plate protective film, the method for producing the polarizing plate is not particularly limited, and can be produced by a general method. For example, there is a method in which the obtained cellulose acylate film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. 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 for bonding 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 for protecting both surfaces of the polarizer, and may further be constructed by laminating 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 protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

The cellulose acylate film of the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer matches the slow axis of the cellulose acylate film of the present invention.
In addition, the polarizing plate produced under polarizing plate crossed Nicol, when the orthogonal accuracy between the slow axis of the cellulose acylate film of the present invention and the absorption axis of the polarizer (axis orthogonal to the transmission axis) is greater than 1 °, Polarization degree performance under a polarizing plate crossed Nicole decreases, light leakage occurs, and when combined with a liquid crystal cell, a sufficient black level and contrast cannot be obtained, so the main refractive index of the cellulose acylate film of the present invention The deviation between the direction of nx and the direction of the transmission axis of the polarizing plate is preferably within 1 °, preferably within 0.5 °.
In the present invention, the single plate transmittance, parallel transmittance, and orthogonal transmittance of the polarizing plate were measured using UV3100PC (manufactured by Shimadzu Corporation). In the measurement, the measurement was performed in the range of 380 nm to 780 nm under the conditions of 25 ° C. and relative humidity 60%, and the average value of 10 measurements was used for each of the single plate, parallel and orthogonal transmittance. The polarizing plate durability test was performed as follows in two types of forms in which (1) only the polarizing plate and (2) the polarizing plate were bonded to glass via an adhesive. For the measurement of only the polarizing plate, two orthogonal and identical ones were prepared and measured so that the optical compensation film was sandwiched between the two polarizers. Two samples (about 5 cm × 5 cm) are prepared by attaching a polarizing plate on a glass so that the optical compensation film is on the glass side. In the single plate transmittance measurement, the film side of this sample was set with the light source facing the light source. Two samples were measured, and the average value was defined as the transmittance of the single plate. The preferable range of polarization performance is 40.0 ≦ TT ≦ 45.0, 30.0 ≦ PT ≦ 40.0, and CT ≦ 2.0 in the order of single plate transmittance, parallel transmittance, and orthogonal transmittance, respectively. More preferable range is 40.2 ≦ TT ≦ 44.8, 32.2 ≦ PT ≦ 39.5, CT ≦ 1.6, and further preferable range is 41.0 ≦ TT ≦ 44.6. 34 ≦ PT ≦ 39.1 and CT ≦ 1.3.
The degree of polarization P is calculated from these transmittances, and the greater the degree of polarization P, the less light leaks when the cross arrangement is made, indicating that the performance of the polarizing plate is higher. The degree of polarization P is preferably 95.0% or more, more preferably 96.0% or more, and further preferably 97.0% or more.

In the polarizing plate of the present invention, T ₍₃₈₀₎ , T ₍₄₁₀₎ , and T ₍₇₀₀₎ are at least one of the following formulas (e) to (g), where T (λ) is the orthogonal transmittance at the wavelength λ. It is preferable to satisfy one or more.
(E) T ₍₃₈₀₎ ≦ 2.0
(F) T ₍₄₁₀₎ ≦ 1.0
(G) T ₍₇₀₀₎ ≦ 0.5
More preferably, T (380) ≦ 1.95, T (410) ≦ 0.9, T (700) ≦ 0.49, and even more preferably T (380) ≦ 1.90, T (410) ≦ 0. .8, T (700) ≦ 0.48.
In the polarizing plate of the present invention, the amount of change ΔCT and the amount of change in polarization ΔP of the orthogonal single plate when left to stand at 60 ° C. and 95% relative humidity for 500 hours have the following formulas (j) and (k): It is preferable to satisfy at least one of the following.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
(However, the amount of change indicates the value obtained by subtracting the measured value before the test from the measured value after the test.)
More preferably, −5.8 ≦ ΔCT ≦ 5.8, −9.5 ≦ ΔP ≦ 0.0, and still more preferably, −5.6 ≦ ΔCT ≦ 5.6, −9.0 ≦ ΔP ≦ 0.0. It is.
In the polarizing plate of the present invention, the amount of change ΔCT and the amount of change in polarization ΔP of the orthogonal single plate when it is allowed to stand for 500 hours at 60 ° C. and 90% relative humidity are expressed by the following formulas (h) and (i). It is preferable to satisfy at least one of the following.
(H) −3.0 ≦ ΔCT ≦ 3.0
(I) −5.0 ≦ ΔP ≦ 0.0
In the polarizing plate of the present invention, the amount of change ΔCT and the degree of polarization change ΔP of the orthogonal single plate when left standing at 80 ° C. for 500 hours have at least one of the following formulas (l) and (m): It is preferable to satisfy.
(L) −3.0 ≦ ΔCT ≦ 3.0
(M) −2.0 ≦ ΔP ≦ 0.0
In the polarizing plate durability test, the amount of change is preferably smaller.

[surface treatment]
The cellulose acylate film of the present invention 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. As the surface treatment, for example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs 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 of the Japan Society of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention). In the plasma treatment at atmospheric pressure, which has been attracting attention in recent years, for example, irradiation energy of 20 to 500 kGy is used under 10 to 1000 KeV, and more preferably irradiation energy of 20 to 300 kGy is used under 30 to 500 KeV. Among these, an alkali saponification treatment is particularly preferable, and it is extremely effective as a surface treatment of a cellulose acylate film.

  The alkali saponification treatment is preferably carried out by a method in which the cellulose acylate film is directly immersed in a saponification solution tank or a method in which the saponification solution is applied to the cellulose acylate film. Examples of the coating method include a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method. The solvent of the alkali saponification coating solution has good wettability in order to apply the saponification solution to the cellulose acylate film, and the surface of the cellulose acylate film surface is not formed by the saponification solution solvent. It is preferred to select a solvent that remains good. Specifically, an alcohol solvent is preferable, and isopropyl alcohol is particularly preferable. An aqueous solution of a surfactant can also be used as a solvent. The alkali of the alkali saponification coating solution is preferably an alkali that dissolves in the above solvent, and more preferably KOH or NaOH. The pH of the saponification coating solution is preferably 10 or more, more preferably 12 or more. The reaction conditions at the time of alkali saponification are preferably 1 second to 5 minutes at room temperature, more preferably 5 seconds to 5 minutes, and particularly preferably 20 seconds to 3 minutes. After the alkali saponification reaction, it is preferable to wash the surface on which the saponification solution is applied with water or with an acid and then with water.

  In the polarizing plate of the present invention, it is preferable that at least one layer of a hard coat layer, an antiglare layer and an antireflection layer is provided on the surface of the protective film on the other side of the polarizing plate. That is, as shown in FIG. 2, it is preferable to provide a functional film such as an antireflection layer on the protective film (TAC2) disposed on the side opposite to the liquid crystal cell when the polarizing plate is used in a liquid crystal display device. It is preferable to provide at least one layer of a hard coat layer, an antiglare layer and an antireflection layer as the functional film. Each layer does not need to be provided as a separate layer. For example, the antireflection layer may function as an antireflection layer and an antiglare layer by providing the antireflection layer with a function as an antiglare layer.

[Antireflection layer]
In the present invention, an antireflection layer in which at least a light scattering layer and a low refractive index layer are laminated in this order on the protective film, or a medium refractive index layer, a high refractive index layer, and a low refractive index layer on the protective film. An antireflection layer formed by laminating in order is preferably used. Preferred examples thereof are described below.

A preferred example of an antireflection layer in which a light scattering layer and a low refractive index layer are provided on a protective film will be described.
It is preferable that mat particles are dispersed in the light scattering layer, and the refractive index of the material other than the mat particles in the light scattering layer is preferably in the range of 1.50 to 2.00. The refractive index of the low refractive index layer is preferably in the range of 1.20 to 1.49. In the present invention, the light scattering layer has both antiglare properties and hard coat properties, and may be a single layer or a plurality of layers, for example, 2 to 4 layers.

The antireflection layer has an uneven surface shape with a center line average roughness Ra of 0.08 to 0.40 μm, a 10-point average roughness Rz of 10 times or less of Ra, an average mountain valley distance Sm of 1 to 100 μm, and an uneven depth. Designed so that the standard deviation of the height of the convex part from the part is 0.5 μm or less, the standard deviation of the average mountain valley distance Sm with respect to the center line is 20 μm or less, and the surface with the inclination angle 0 to 5 degrees is 10% or more By doing so, sufficient anti-glare properties and a visually uniform matte feeling are achieved, which is preferable. In addition, the ratio of the minimum value and the maximum value of the reflectance in the range of a ^* value −2 to 2, b ^* value −3 to 3, and 380 nm to 780 nm is 0. By being 5-0.99, the color of reflected light becomes neutral, which is preferable. Moreover, by setting the b ^* value of the transmitted light under the C light source to 0 to 3, the yellow color of white display when applied to a display device is reduced, which is preferable. In addition, when a 120 μm × 40 μm grid is inserted between the surface light source and the antireflection film of the present invention and the luminance distribution is measured on the film, the standard deviation of the luminance distribution is 20 or less. Glare when applying the film of the present invention is reduced, which is preferable.

  The antireflection layer that can be used in the present invention preferably has, as its optical characteristics, a specular reflectance of 2.5% or less, a transmittance of 90% or more, and a 60 ° gloss of 70% or less. By doing in this way, reflection of external light can be suppressed and visibility improves. In particular, the specular reflectance is more preferably 1% or less, and most preferably 0.5% or less. Haze 20% to 50%, internal haze / total haze value 0.3 to 1, haze value after formation of low refractive index layer from haze value to light scattering layer within 15%, comb width at 0.5 mm Transmission image clarity 20% to 50%, vertical transmission light / transmittance ratio of 2 degrees from vertical to 1.5 to 5.0 prevents glare on high-definition LCD panels, characters, etc. Reduction of blur is achieved, which is preferable.

[Low refractive index layer]
The low refractive index layer in the antireflection layer in which at least a light scattering layer and a low refractive index layer are laminated in this order on the protective film will be described below.
The refractive index of the low refractive index layer is preferably 1.20 to 1.49, more preferably 1.30 to 1.44. Further, the low refractive index layer preferably satisfies the following formula (XV) from the viewpoint of reducing the reflectance.
Formula (XV): (m / 4) × 0.7 <n1d1 <(m / 4) × 1.3
In the formula, m is a positive odd number, n1 is the refractive index of the low refractive index layer, and d1 is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength, which is a value in the range of 500 to 550 nm.

The material for forming the low refractive index layer will be described below.
The low refractive index layer preferably contains a fluorine-containing polymer as a low refractive index binder. The fluorine polymer is preferably a fluorine-containing polymer that is crosslinked by heat or ionizing radiation with a coefficient of dynamic friction of 0.03 to 0.20, a contact angle with water of 90 to 120 °, and a sliding angle of pure water of 70 ° or less. When the polarizing plate of the present invention is mounted on an image display device, the lower the peel strength from a commercially available adhesive tape, the easier it is to peel off after sticking a sticker or memo, preferably 500 gf or less when measured with a tensile tester. 300 gf or less is more preferable, and 100 gf or less is most preferable. Further, the higher the surface hardness measured with a micro hardness tester, the harder it is to scratch, preferably 0.3 GPa or more, more preferably 0.5 GPa or more.

  Examples of the fluorine-containing polymer used in the low refractive index layer include hydrolysis and dehydration condensate of perfluoroalkyl group-containing silane compounds (for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane). And a fluorine-containing copolymer having a fluorine-containing monomer unit and a structural unit for imparting crosslinking reactivity as structural components.

  Specific examples of the monomer that forms the fluorine-containing monomer unit that is a constituent of the fluorine-containing copolymer include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, Perfluoro-2,2-dimethyl-1,3-dioxole, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (Osaka Organic Chemical) or M-2020 (Daikin)) Etc.), fully or partially fluorinated vinyl ethers, and the like, preferably perfluoroolefins, and particularly preferably hexafluoropropylene from the viewpoints of refractive index, solubility, transparency, availability, and the like.

  As structural units for imparting crosslinking reactivity, structural units obtained by polymerization of monomers having a self-crosslinkable functional group in the molecule in advance such as glycidyl (meth) acrylate and glycidyl vinyl ether, carboxyl groups, hydroxy groups, amino acids Polymerization of monomers having a group, a sulfo group, etc. (eg (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc.) The resulting structural unit, a structural unit in which a crosslinking reactive group such as a (meth) acryloyl group is introduced into these structural units by a polymer reaction (for example, an acrylic acid chloride is allowed to act on a hydroxy group). And the like.

  In addition to the above-mentioned fluorine-containing monomer units and structural units for imparting crosslinking reactivity, monomers not containing fluorine atoms can be copolymerized as appropriate from the viewpoints of solubility in solvents and film transparency. The monomer that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-acrylic acid 2- Ethyl hexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether) , Ethyl vinyl ether, cyclohexyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate etc.), acrylamides (N-tert-butylacrylamide, N-cycl) Hexyl acrylamide), methacrylamides, and acrylonitrile derivatives.

  As described in JP-A-10-25388 and JP-A-10-147739, a curing agent may be appropriately used in combination with the above polymer.

[Light scattering layer]
The light scattering layer is formed for the purpose of contributing to the film light diffusibility due to at least one of surface scattering and internal scattering, and hard coat properties for improving the scratch resistance of the film. Therefore, it is formed including a binder for imparting hard coat properties, matte particles for imparting light diffusibility, and inorganic fillers for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength as necessary. The In addition, by providing such a light scattering layer, the light scattering layer also functions as an antiglare layer, and the polarizing plate has an antiglare layer.

  The thickness of the light scattering layer is preferably 1 to 10 μm and more preferably 1.2 to 6 μm for the purpose of imparting hard coat properties. If it is too thin, the hard property will be insufficient, and if it is too thick, curling and brittleness will deteriorate and the workability will be insufficient.

  The binder of the light scattering layer is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as the main chain, and more preferably a polymer having a saturated hydrocarbon chain as the main chain. The binder polymer preferably has a crosslinked structure. As the binder polymer having a saturated hydrocarbon chain as a main chain, a polymer of an ethylenically unsaturated monomer is preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable. In order to make the binder polymer have a high refractive index, the monomer structure contains an aromatic ring or at least one atom selected from halogen atoms other than fluorine, sulfur atoms, phosphorus atoms, and nitrogen atoms. You can also choose.

  Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di ( (Meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol Tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3 Cyclohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), modified ethylene oxide, vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4 -Divinylcyclohexanone), vinyl sulfone (eg divinyl sulfone), acrylamide (eg methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

  Specific examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4'-methoxyphenyl thioether, and the like. Two or more of these monomers may be used in combination.

Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
Therefore, a coating liquid containing a monomer having an ethylenically unsaturated group, a photo radical initiator or a thermal radical initiator, mat particles, and an inorganic filler is prepared, and the coating liquid is applied onto a protective film and then ionizing radiation or heat. It can be cured by a polymerization reaction to form an antireflection film. As these photo radical initiators, known ones can be used.

The polymer having a polyether as the main chain is preferably a ring-opening polymer of a polyfunctional epoxy compound. The ring-opening polymerization of the polyfunctional epoxy compound can be performed by irradiation with ionizing radiation or heating in the presence of a photoacid generator or a thermal acid generator.
Therefore, a coating liquid containing a polyfunctional epoxy compound, a photoacid generator or a thermal acid generator, matte particles and an inorganic filler is prepared, and the coating liquid is applied on a protective film and then cured by ionizing radiation or heat polymerization reaction. Thus, an antireflection film can be formed.

Instead of or in addition to a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the polymer, and by reaction of this crosslinkable functional group, A crosslinked structure may be introduced into the binder polymer.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.
These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.

For the purpose of imparting antiglare properties, the light-scattering layer contains matte particles having an average particle size of 1 to 10 μm, preferably 1.5 to 7.0 μm, such as inorganic compound particles or resin particles. Is done.
As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, crosslinked acrylic styrene particles, and silica particles are preferable. The shape of the mat particles can be either spherical or irregular.

  Further, two or more kinds of mat particles having different particle sizes may be used in combination. It is possible to impart anti-glare properties with mat particles having a larger particle size and to impart other optical characteristics with mat particles having a smaller particle size.

  Furthermore, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when particles having a particle size of 20% or more than the average particle size are defined as coarse particles, the proportion of coarse particles is preferably 1% or less, more preferably 0.1% of the total number of particles. Or less, more preferably 0.01% or less. The matting particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree thereof.

The mat particles are contained in the light scattering layer so that the amount of mat particles in the formed light scattering layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .
The particle size distribution of the matte particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

The light scattering layer is made of an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the matte particles, in order to increase the refractive index of the layer. Thus, it is preferable that an inorganic filler having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less is contained.
Conversely, in order to increase the difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the light scattering layer using the high refractive index mat particles low. The preferred particle size is the same as that of the inorganic filler described above.
Specific examples of the inorganic filler used in the light scattering layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO ₂ . TiO ₂ and ZrO ₂ are particularly preferable from the viewpoint of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the light scattering layer, more preferably 20 to 80%, and particularly preferably 30 to 75%.
Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of binder and inorganic filler in the light scattering layer is preferably 1.50 to 2.00, more preferably 1.51 to 1.80. In order to make the refractive index within the above range, the type and amount ratio of the binder and the inorganic filler may be appropriately selected. How to select can be easily known experimentally in advance.

  In order to ensure surface uniformity such as uneven coating, uneven drying, point defects, etc., the light scattering layer should be coated with either a fluorine-based surfactant or a silicone-based surfactant, or both for forming the light scattering layer. Contained in the composition. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the antireflection film of the present invention appears in a smaller addition amount. The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity.

Next, an antireflection layer in which a middle refractive index layer, a high refractive index layer, and a low refractive index layer are laminated in this order on the protective film will be described.
The antireflection layer comprising at least a middle refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) in order on the protective film is designed to have a refractive index satisfying the following relationship. .
High refractive index layer refractive index> Medium refractive index layer refractive index> Protective film refractive index> Low refractive index layer refractive index A hard coat layer may be provided between the protective film and the medium refractive index layer. . Furthermore, it may consist of a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer.
Examples thereof include antireflection layers described in JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706, and the like.
Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (for example, JP-A-10-206603, JP-A-2002). -243906 publication etc.) etc. are mentioned.
The haze of the antireflection layer is preferably 5% or less, more preferably 3% or less. The strength of the film is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400.

[High refractive index layer and medium refractive index layer]
The layer having a high refractive index of the antireflection layer is composed of a cured film containing at least an inorganic compound fine particle having a high refractive index having an average particle size of 100 nm or less and a matrix binder.
The inorganic compound fine particles having a high refractive index include inorganic compound fine particles having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include fine particles such as oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.
In order to obtain fine particles having an average particle size of 100 nm or less, the surface of the particles is treated with a surface treatment agent (for example, silane coupling agents, etc .: JP-A Nos. 1-295503, 11-153703, and 2000). No.-9908, an anionic compound or an organometallic coupling agent: Japanese Patent Laid-Open No. 2001-310432, etc., and a core-shell structure with high refractive index particles as a core (for example, Japanese Patent Laid-Open No. 2001-166104) ), Specific dispersants (for example, JP-A-11-153703, US Pat. No. 6,210,858B1, JP-A-2002-27776069, etc.) and the like.
Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.
Further, a polyfunctional compound-containing composition containing two or more polymerizable groups of at least one of radically polymerizable and cationically polymerizable, an organometallic compound containing a hydrolyzable group, and a partial condensate-containing composition thereof At least one composition selected is preferred. For example, the composition as described in Unexamined-Japanese-Patent No. 2000-47004, 2001-315242, 2001-31871, 2001-296401 etc. is mentioned.
A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, it describes in Unexamined-Japanese-Patent No. 2001-293818.
The refractive index of the high refractive index layer is preferably 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70. The thickness is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.

[Low refractive index layer]
Next, the low refractive index layer in the antireflection layer in which the middle refractive index layer, the high refractive index layer, and the low refractive index layer are laminated in this order on the protective film will be described.
The low refractive index layer is formed by sequentially laminating on the high refractive index layer. The refractive index of the low refractive index layer is preferably 1.20 to 1.55. More preferably, it is 1.30-1.50.
It is preferable to construct as the outermost layer having scratch resistance and antifouling property. As means for greatly improving the scratch resistance, imparting slipperiness to the surface is effective, and conventionally known thin film layer means such as introduction of silicone or introduction of fluorine can be applied.
The fluorine-containing compound is preferably a compound containing a crosslinkable or polymerizable functional group containing fluorine atoms in the range of 35 to 80% by mass.
For example, paragraph numbers [0018] to [0026] of Japanese Patent Application Laid-Open No. 9-222503, paragraph numbers [0019] to [0030] of Japanese Patent Application Laid-Open No. 11-38202, and paragraph numbers of Japanese Patent Application Laid-Open No. 2001-40284. [0027] to [0028], JP-A 2000-284102, and the like.
The refractive index of the fluorine-containing compound is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47.
The silicone compound is a compound having a polysiloxane structure, preferably containing a curable functional group or a polymerizable functional group in the polymer chain and having a crosslinked structure in the film. For example, reactive silicone (for example, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane (Japanese Patent Laid-Open No. 11-258403, etc.) and the like can be mentioned.
The crosslinking or polymerization reaction of at least one of a fluorine-containing polymer having a crosslinking or polymerizable group and a siloxane polymer is performed by applying a coating composition for forming an outermost layer containing a polymerization initiator, a sensitizer and the like. It is preferable to form the low refractive index layer by light irradiation or heating simultaneously or after coating.

Also preferred is a sol-gel cured film in which an organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent are cured by a condensation reaction in the presence of a catalyst.
For example, a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate thereof (Japanese Patent Laid-Open Nos. 58-142958, 58-147483, 58-147484, Japanese Patent Laid-Open Nos. 9-157582, 11) -106704 and the like), silyl compounds containing a poly "perfluoroalkyl ether" group which is a fluorine-containing long chain group (Japanese Patent Application Laid-Open Nos. 2000-117902, 2001-48590, 2002) 53804), and the like.

The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as a filler (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as an additive other than the above. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820, etc.), silane coupling agents, slip agents, surfactants, and the like can be contained.
When the low refractive index layer is positioned below the outermost layer, the low refractive index layer may be formed by a vapor phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, etc.). The coating method is preferable because it can be manufactured at a low cost.
The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

[Hard coat layer]
The hard coat layer is provided on the surface of the protective film in order to impart physical strength to the protective film provided with the antireflection layer. In particular, it is preferably provided between the transparent support and the high refractive index layer. The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of the curable compound by at least one of light and heat. The curable functional group in the curable compound is preferably a photopolymerizable functional group. Also preferred are hydrolyzable functional group-containing organometallic compounds and organoalkoxysilyl compounds.
Specific examples of these compounds are the same as those exemplified for the high refractive index layer. Specific examples of the composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO 00/46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.
The hard coat layer can also serve as an antiglare layer containing particles having an average particle size of 0.2 to 10 μm and imparting an antiglare function (antiglare function).
The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

[Other layers of antireflection layer]
Further, a forward scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

[Antistatic layer]
In the case of providing an antistatic layer, it is preferable to impart conductivity with a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less. The use of hygroscopic substances, water-soluble inorganic salts, certain surfactants, cationic polymers, anionic polymers, colloidal silica, etc. can give a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ). There is a problem that dependency is large, and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material. Some metal oxides are colored, but using such metal oxides as the conductive layer material is not preferable because the entire film is colored. Zn, Ti, Al, In, Si, Mg, Ba, Mo, W, or V can be given as the metal that forms the metal oxide without coloration, and a metal oxide mainly composed of this can be used. preferable. As specific examples, ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ , V ₂ O _5, or a composite oxide thereof is particularly preferable. ZnO, TiO ₂ and SnO ₂ are preferred. Examples of containing different atoms include, for example, additives such as Al and In for ZnO, addition of Sb, Nb and halogen elements for SnO ₂ , and Nb and TA for TiO ₂ . Addition is effective. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a material obtained by adhering the above metal oxide to other crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. The volume resistance value and the surface resistance value are different physical properties and cannot be simply compared. However, in order to secure conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance, The prevention layer should just have a surface resistance value of 10 ⁻¹⁰ (Ω / □) or less, more preferably 10 ⁻⁸ (Ω / □) or less. The surface resistance value of the antistatic layer is a value when the antistatic layer is the outermost layer, and can be measured in the middle of forming the antistatic layer.

[Liquid Crystal Display]
(General liquid crystal display device configuration)
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 having a liquid crystal 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-ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Supper Twisted Nematic), VA (Vertically Aligned), 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 sheet 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 sheet used in 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. Also described in Mori et al. (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 and Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068). is there.

(STN type liquid crystal display device)
The cellulose acylate film of the present invention may be used as a support for an optical compensation sheet of an STN type liquid crystal display device having an STN mode liquid crystal cell or as a protective film for a polarizing plate. In general, in a STN type liquid crystal display device, rod-like liquid crystalline molecules in a liquid crystal cell are twisted in the range of 90 to 360 degrees, and the refractive index anisotropy (Δn) and cell gap (d) of the rod-like liquid crystalline molecules. Product (Δnd) is in the range of 300 to 1500 nm. The optical compensation sheet used in the STN type liquid crystal display device is described in JP-A-2000-105316.

(VA type liquid crystal display device)
The cellulose acylate film of the present invention may be used as a support for an optical compensation sheet of a VA liquid crystal display device having a VA mode liquid crystal cell or as a protective film for a polarizing plate. It is preferable that the Re retardation value of the optical compensation sheet used in the VA liquid crystal display device is 0 to 150 nm and the Rth retardation value is 70 to 400 nm. The Re retardation value is more preferably 20 to 70 nm. When two optically anisotropic polymer films are used in a VA liquid crystal display device, the Rth retardation value of the film is preferably 70 to 250 nm. When one optically anisotropic polymer film is used for the VA liquid crystal display device, the Rth retardation value 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 can be used as an IPS liquid crystal display device having an IPS mode and an ECB mode liquid crystal cell and an optical compensation sheet for an ECB liquid crystal display device, a support for the optical compensation sheet, or a protective film for a polarizing plate. Particularly advantageously used. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and black is displayed by aligning liquid crystal molecules in parallel with the substrate surface in the absence of applied voltage. In these embodiments, the polarizing plate using the cellulose acylate film of the present invention contributes to widening the viewing angle and improving the contrast.
Particularly for IPS liquid crystal display devices, Re is 200 to 330 nm, | Nz | is 0.3 to 0.7, more preferably Re is 220 to 300 nm, | Nz | is 0.4 to 0.6, and Preferably, the cellulose acylate film of the present invention having Re of 250 to 290 nm and | Nz | of 0.4 to 0.6 is used as the cell-side protective film of the polarizing plate, and the polarizing plate opposing the liquid crystal cell For the cell-side protective film, it is preferable to use a film having Re of 3 nm or less and an absolute value of Rth value | Rth | of 10 nm or less, more preferably Re of 1 nm or less and | Rth |

(OCB type liquid crystal display device and HAN type liquid crystal display device)
The cellulose acylate film of the present invention is used as a support for an optical compensation sheet or a protective film for a polarizing plate 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. Also good. In the optical compensation sheet used for the OCB type liquid crystal display device or the HAN type liquid crystal display device, it is preferable that the direction in which the absolute value of retardation is minimum does not exist in the plane of the optical compensation sheet or in the normal direction. The optical properties of the optical compensation sheet used in the OCB type liquid crystal display device or the 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 sheet used for an OCB type liquid crystal display device or a HAN type liquid crystal display device is described in JP-A-9-197397. It is also described in Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

(Reflective liquid crystal display)
The cellulose acylate film of the present invention may be used as a protective film for an optical compensation sheet or a polarizing plate 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 sheet 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 may be used as a support for an optical compensation sheet of an ASM type liquid crystal display device having a liquid crystal cell of ASM (Axially Symmetric Aligned Microcell) mode or as a protective film for a polarizing plate. 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)).

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

[Example 1]
(Cellulose acylate)
As described in Table 1, cellulose acylates having different acyl groups and different degrees of substitution were prepared according to the following procedure.
7.8 parts by mass of sulfuric acid as a catalyst was added to 100 parts by mass of cellulose, and carboxylic acid serving as a raw material for the acyl substituent was added to carry out an acylation reaction at 40 ° C. At this time, by adjusting the type and amount of carboxylic acid, the type of acyl group and the degree of substitution were adjusted as described in Table 1. After acylation, aging was performed at 40 ° C. The low molecular weight component of cellulose acylate in the obtained mixture was removed by washing with acetone. In Table 1, CAP is an abbreviation for cellulose acetate propionate (cellulose ester derivative whose acyl group is composed of acetyl group and propionyl group), and CAB is cellulose acetate butyrate (acyl group is composed of acetyl group and butyl group). CTA is an abbreviation for cellulose triacetate (a cellulose ester derivative in which an acyl group is composed only of an acetyl group).

(Preparation of dope)
<1-1> Preparation of Cellulose Acylate Solution The following composition is put into a mixing tank, stirred to dissolve each component, and further heated at 90 ° C. for about 10 minutes, followed by filter paper having an average pore size of 34 μm and an average pore size of 10 μm. A cellulose acylate solution was prepared by filtration through a sintered metal filter.
―――――――――――――――――――――――――――――――――
Cellulose acylate solution ――――――――――――――――――――――――――――――――――
Cellulose triacetate (degree of substitution 2.85) 100.0 parts by mass Methylene chloride 403.0 parts by mass Methanol 60.2 parts by mass ――――――――――――――――――――――― ――――――――――

<1-2> Preparation of Matting Agent Dispersion The following composition containing the cellulose acylate solution prepared by the above method was charged into a disperser to prepare a matting agent dispersion.
――――――――――――――――――――――――――――――――――
Matting agent dispersion ――――――――――――――――――――――――――――――――――
Silica particles having an average particle size of 16 nm (aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride 72.4 parts by mass Methanol 10.8 parts by mass Cellulose acylate solution 10.3 parts by mass ――――――――――――――――――――――――――――

<1-3> Preparation of Re enhancer solution The following composition containing the cellulose acylate solution prepared by the above method was charged into a mixing tank and dissolved by stirring while heating to prepare a Re enhancer solution.
―――――――――――――――――――――――――――――――――
Re developer solution ―――――――――――――――――――――――――――――――――
Re enhancer A-12 20.0 parts by mass Methylene chloride 58.3 parts by mass Methanol 8.7 parts by mass Cellulose acylate solution 12.8 parts by mass ――――――――――――――――― ――――――――――――――――

  When the cellulose acylate was 100 parts by mass, the above solution was mixed so that the matting agent was 0.15 part by mass and the Re developing agent was in the ratio shown in Table 1, and a mixed solvent, dichloromethane / methanol (87 / 13 parts by mass) was added while stirring so that the mass concentration of cotton was 19% by mass, and heated to stir and dissolved to prepare a dope for film formation.

(Casting)
The above dope was cast at a speed of 20 m / min (film forming speed) using a band casting machine. A film peeled off from the band with a residual solvent amount (wet ratio) of 25 to 35% by mass was supplied at a supply temperature of 140 ° C. (exhaust temperature in the range of 90 ° C. to 125 ° C.) in the tenter zone, and a draw ratio of 80% ( The cellulose acylate film 1 (thickness 92 μm, width 1.3 m, length 2600 m) having a slow axis in the plane perpendicular to the machine direction was produced.

[Examples 2 to 14 and Comparative Examples 1 and 2]
The cellulose acylate film of the present invention was prepared in the same procedure as in Example 1, except that the type of acyl group, the degree of substitution, the type and amount of Re enhancer, the draw ratio, and the film thickness were changed as shown in Table 1. Cellulose acylate films C1 and C2 of 2 to 18 and Comparative Examples were produced.

[Test Example 1]
The results of measuring Re, Rth, and | Nz | for each of the cellulose acylate films obtained in Examples 1 to 14 and Comparative Examples 1 and 2 are summarized in Table 1. Re and Rth were measured using KOBRA 21ADH as described above.

[Examples 101 to 114 and Comparative Examples 101 and 102]
(Preparation of polarizing plate)
The cellulose acylate film 1 is immersed in a 1.5 mol / L NaOH aqueous solution (saponification solution) adjusted to 60 ° C. for 2 minutes, then immersed in a 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, and further passed through a water washing bath. Washed away. Finally, the sample was thoroughly dried at 120 ° C.
According to Example 1 of Japanese Patent Laid-Open No. 2001-141926, a Fujitac (TD-80UF) is formed on one surface of a polarizing film having a thickness of 20 μm, which is produced by giving a circumferential speed difference between two pairs of nip rolls and extending in the longitudinal direction. ), And the cellulose acylate film 1 of the present invention saponified on the other side is bonded together with a 3% aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray Co., Ltd.) as an adhesive, and the absorption axis of the polarizer and the cellulose acylate film 1 The polarizing plate 101 was produced so that the in-plane slow axis was orthogonal.

(Preparation of counter polarizing plate)
The following composition was put into a mixing tank and stirred to dissolve each component. Silica particles were added after being dispersed in a solvent in advance.
――――――――――――――――――――――――――――――――――――――
Cellulose acylate solution A
――――――――――――――――――――――――――――――――――――――
Cellulose acetate having an average degree of acetylation of 2.93 100.0 parts by mass Methylene chloride (first solvent) 517.6 parts by mass Methanol (second solvent) 77.3 parts by mass Silica particles having an average particle size of 16 nm 0.13 parts by mass (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
Compound that lowers optical anisotropy (the following structural formula) 11.7 parts by mass Wavelength dispersion modifier (UV-102) 1.2 parts by mass Citrate ester 0.01 parts by mass ―――――――――― ――――――――――――――――――――――――――――

The cellulose acylate solution A was cast using a band casting machine, and the film was peeled off from the band with a residual solvent amount of about 60% and conveyed by a tenter.
The average temperature of the drying zone was 135 ° C. The obtained cellulose acylate film L1 had Re = 0.3 nm and Rth = 1.0 nm.
A polarizing plate L101 was produced using the thus produced film and TD-80UF in the same manner as the polarizing plate 101.

偏光板１０１および偏光板Ｌ１０１を用いて、液晶表示装置のパネルに実装して評価を行った。

The polarizing plate 101 and the polarizing plate L101 were used for evaluation on a panel of a liquid crystal display device.

(Production of IPS mode liquid crystal cell)
On one glass substrate, electrodes were arranged so that the distance between adjacent electrodes was 20 μm, and a polyimide film was provided as an alignment film thereon, and a rubbing treatment was performed. A polyimide film was provided on one surface of a separately prepared glass substrate, and a rubbing treatment was performed to obtain an alignment film. The two glass substrates are stacked and bonded so that the alignment films face each other, the distance between the substrates (gap; d) is 3.9 μm, and the rubbing directions of the two glass substrates are parallel. A nematic liquid crystal composition having a refractive index anisotropy (Δn) of 0.0769 and a dielectric anisotropy (Δε) of 4.5 was enclosed. The value of d · Δn of the liquid crystal layer was 300 nm.

  The polarizing plate 101 of the present invention is placed on the light source side of the liquid crystal cell with an adhesive so that the slow axis of the liquid crystal cell and the absorption axis of the polarizing plate 101 are orthogonal to each other, and the cellulose acylate film 1 is on the liquid crystal cell side. The IPS liquid crystal display device 101 is attached to the opposite side of the liquid crystal cell so that the cellulose acylate film L1 side of the polarizing plate L101 faces the liquid crystal cell so that the absorption axis of the polarizing plate 101 is orthogonal to the opposite side of the liquid crystal cell. Produced.

[Examples 102 to 114 and Comparative Examples 101 and 102]
Using the cellulose acylate films 2 to 12, C1, and C2 prepared in Examples 2 to 12 and Comparative Examples 1 and 2, polarizing plate processing was performed in the same manner as Example 101, and IPS liquid crystal display devices 102 to 112 and C101 were processed. , C102 was produced.

[Test Example 2]
(Evaluation of retardation film and measurement of leakage light of the manufactured liquid crystal display device)
The viewing angle dependence of the transmittance of the manufactured liquid crystal display device was measured. The depression angle was measured from the front to the diagonal direction up to 80 ° every 10 °, and the azimuth angle was measured up to 360 ° every 10 ° on the basis of the horizontal right direction (0 °). It has been found that the luminance during black display increases as the angle of suppression increases from the front direction, and the leakage light transmittance also increases, and takes a maximum value near the angle of suppression of 70 °. It was also found that the contrast deteriorates as the black display transmittance increases. Therefore, it was decided to evaluate the viewing angle characteristics with the maximum values of the black display transmittance on the front side and the leaked light transmittance with a suppression angle of 60 °.
Evaluation of display characteristics ◎ Very small viewing angle characteristic difference and very good ○ Little viewing angle characteristic difference and good △ Little viewing angle characteristic difference × Large viewing angle characteristic difference

  The results are shown in Table 2.

  The cellulose acylate film of the present invention is excellent in in-plane retardation (Re) and has a small thickness direction retardation (Rth). In addition, the cellulose acylate film of the present invention has an excellent optical compensation ability and also has a feature of high productivity. In particular, a polarizing plate using the cellulose acylate film of the present invention as a protective film for a polarizer is useful in that it can provide a liquid crystal display device with little change in viewing angle characteristics. Therefore, the present invention has high industrial applicability.

Claims (11)

A cellulose acylate film characterized by satisfying the following formula:
50 nm <Re <400 nm
−200 nm ≦ Rth ≦ 50 nm
| Nz | ≦ 10
(In the above formula, Re represents retardation in the in-plane direction of the cellulose acylate film, Rth represents retardation in the thickness direction of the cellulose acylate film, and Nz represents (Rth / Re) +0.5.)   It is a cellulose acylate film of Claim 1, Comprising: The substitution degree of the cellulose acylate contained in this film is 2.85 to 3.00, The cellulose acylate film characterized by the above-mentioned.   The cellulose acylate film according to claim 1 or 2, wherein the film contains a rod-like compound or a discotic compound.   It is a cellulose acylate film as described in any one of Claims 1-3, Comprising: The width | variety of this film is 0.5-3 m, The cellulose acylate film characterized by the above-mentioned.   It is a cellulose acylate film as described in any one of Claims 1-4, Comprising: The film thickness of this film is 40-200 micrometers, The cellulose acylate film characterized by the above-mentioned.   The cellulose acylate film according to any one of claims 1 to 5, wherein a slow axis in the plane of the film is in a direction perpendicular to the machine direction.   A polarizing plate comprising a polarizing film and two films provided on both sides thereof, wherein at least one of the films comprises the cellulose acylate film according to any one of claims 1 to 6. Polarizing plate.   A liquid crystal display device using the polarizing plate according to claim 7.   9. The liquid crystal display device according to claim 8, wherein an IPS liquid crystal display mode is used.   A solution containing cellulose acylate having a substitution degree of 2.85 to 3.00 and at least one of a rod-like compound and a discotic compound is cast on a support, and then the formed film is peeled and stretched. A method for producing a cellulose acylate film.   The method for producing a cellulose acylate film according to claim 10, wherein the film forming speed is 5 to 300 m / min.