JP2006249328A - Cellulose acylate film, retardation film, polarized plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose acylate film wherein retardation at the whole visual range is small, substantially an optical isotropy is attained, a wavelength dispersion is small and an axial dispersion is small, and also to provide a retardation film in which angular field of view properties upon installed in a liquid crystal display device is excellent and further to provide a polarized plate using the same and a liquid crystal display device having an excellent angular field of view. <P>SOLUTION: In the cellulose acylate film, Re(λ) and Rth(λ) satisfy (I)0≤Re(590)≤10 and ¾Rth(590)¾≤25, and (II) ¾Re(400)-Re(700)¾≤10 and ¾Rth(400)-Rth(700)¾≤35 and a slow phase axial direction is 0°±10° or 90°±10° in a film longitudinal direction, wherein the units of Re(λ) and Rth(λ) are nm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cellulose acylate film useful for a liquid crystal display device, an optical material such as a retardation film and a polarizing plate, and a liquid crystal display device.

  The cellulose acylate film is excellent as an optical member for a liquid crystal display device that handles polarized light because of its high optical transparency, high optical isotropy, and ease of polarizing plate processing. It has been used as a support for a protective film or a retardation film capable of improving the visibility (viewing angle compensation) of a display screen viewed from an oblique direction.

  However, even though the conventional cellulose acylate film is optically isotropic within the film plane, it has retardation in the thickness direction. For example, a commercially available cellulose triacetate film (TD80U, Fuji Photo Film Co., Ltd.) Manufactured) was known to have a retardation of 40 to 50 nm. Therefore, in order to realize the optimum display quality in the oblique direction, it is necessary to perform optical design in consideration of this retardation. For example, when it is necessary to reduce the retardation in the oblique direction, the optical anisotropy for compensating the retardation in the thickness direction of the cellulose acylate film in addition to the optically anisotropic layer for optical compensation of the liquid crystal cell There were limitations such as the need for layers. Therefore, a film that is optically isotropic with respect to retardation in the thickness direction has been desired (for example, Patent Document 1).

  The birefringence of the cellulose triacetate film has a wavelength dispersion characteristic that is larger on the longer wavelength side in the visible light region. On the other hand, it is known that the wavelength dispersion of the birefringence of the liquid crystal used in the liquid crystal cell is generally larger on the short wavelength side. For this reason, even if the optical design is optimal for optical compensation at a specific wavelength, there is a problem in that optical characteristics shift at other wavelengths and problems such as coloring occur.

  Recently, liquid crystal display devices are widely used not only for PC monitors and portable devices but also for television applications, and there is a strong demand for better contrast and color viewing angle characteristics than before. It has become like this. In addition, there is a strong need for an increase in size and price in television applications, and a protective film and a retardation film are required that have a uniform performance over a larger area and are low in cost. In order to satisfy such a demand, a film that eliminates the limitations and problems of retardation as described above and further reduces “unevenness” that impairs display quality is required.

JP 2001-249599 A

The first problem of the present invention is that when the retardation is incorporated in a liquid crystal display device or a cellulose acylate film having a small retardation over the entire visible range and a small axial variation (variation depending on the location of the slow axis and the fast axis). A retardation film having excellent viewing angle characteristics and a polarizing plate using the same are provided.
A second object of the present invention is to provide a liquid crystal display device excellent in viewing angle characteristics.

  As a result of intensive studies by the inventors of the present invention, in order to solve the problem, the in-plane and thickness direction retardation of the cellulose acylate film needs to be as close to zero as possible in the entire visible light region. As a result, a cellulose acylate film having such characteristics was pursued from the viewpoint of production formulation and production conditions.

  As a result, the inventors of the present invention sufficiently reduced the optical anisotropy by using a compound that suppresses the in-plane and film thickness orientation of the cellulose acylate in the film, and set Re and Rth. Succeeded to approach zero. It has also been found that cellulose acylate having a high acyl substitution degree of 2.80 to 3.00 can also contribute to the solution of the above problems.

  Furthermore, the inventors of the present invention use a compound that can prevent the coloring of the film by having absorption in the ultraviolet region of a wavelength of 200 to 400 nm and control the wavelength dispersion of Re (λ) and Rth (λ) of the film. Successfully reduced the difference between Re and Rth at wavelengths of 400 nm and 700 nm, | Re (400) −Re (700) | and | Rth (400) −Rth (700) |.

  Furthermore, the inventors of the present invention applied a stronger tension in the width direction during production of the cellulose acylate film than in the case of producing a generally known cellulose triacetate film, and the in-plane slow axis direction was in the direction of the film. It has been found that it is effective for the purpose of the invention to manufacture the film so as to be substantially parallel or substantially perpendicular to the length direction. That is, when the tension is about the same as that of a normal cellulose acylate film, the slow axis direction varies, and it is easily detected as unevenness when used in a liquid crystal display device. In a normal cellulose triacetate film, when a tension as in the present invention is applied, a phase difference occurs and the optical performance which is the subject of the present invention cannot be satisfied. However, in the present invention, a cellulose acylate having a high acyl substitution degree and a retardation reducing agent Since it was found that even when tension was applied, it was difficult to develop a phase difference, so that the problem was achieved by the above-described means.

Specifically, the object of the present invention can be achieved by a cellulose acylate film, a retardation film, a polarizing plate, and a liquid crystal display device described below in combination with the above-described new knowledge.
(1) Re (λ) and Rth (λ) satisfy the following formulas (I) and (II), and the in-plane slow axis direction is 0 ° ± 10 ° with respect to the film length direction or A cellulose acylate film characterized by being 90 ° ± 10 °.
Formula (I): 0 ≦ Re (590) ≦ 10 and | Rth (590) | ≦ 25 Formula (II): | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700 ) | ≦ 35
[Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. ]
(2) The cellulose acylate film has an acyl substitution degree of 2.80 to 3.00, and contains at least one compound that lowers Re (λ) and Rth (λ) in the film. The cellulose acylate film according to (1) above.
(3) The cellulose acylate film as described in (1) or (2) above, wherein the film thickness is from 10 μm to 120 μm.
(4) The cellulose acylate film as described in any one of (1) to (3) above, wherein the film is a film produced with a width of 600 mm or more and a length of 100 m or more.

(5) In the production process of the cellulose acylate film, by applying a tension of 10 to 50 kgf / m (98 to 490 N / m) in the width direction of the film, the in-plane slow axis direction is set to the film length direction. 0 ° ± 10 ° or 90 ° ± 10 °, and Re (λ) and Rth (λ) of the cellulose acylate film satisfy the following formulas (I) and (II): A method for producing a rate film.
Formula (I): 0 ≦ Re (590) ≦ 10 and | Rth (590) | ≦ 25
Formula (II): | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. ]
(6) A method for producing a cellulose acylate film by a solution casting method, wherein the film is transported and dried while tension is applied in the width direction of a film containing at least 10% or more of a solvent. The method for producing a cellulose acylate film as described in (5) above, wherein
(7) A method for producing a cellulose acylate film by a solution casting method, which holds both ends of the film and conveys the film while applying tension in the width direction of the film, so that the residual solvent amount becomes 40% or less. (5), wherein the film is detached from the holding of both ends, and then transported with a transport tension of 2 to 20 kgf / m (19.6 to 196 N / m) and dried. ) Or the method for producing a cellulose acylate film according to (6).
(8) The method for producing a cellulose acylate film according to any one of claims 5 to 7, wherein the film is dried at 100 to 150 ° C after releasing the holding of both ends of the film.

(9) A retardation film, wherein at least one optically anisotropic layer is provided on the cellulose acylate film according to any one of (1) to (4).
(10) A polarizing plate, wherein at least one protective film of the polarizing plate is the cellulose acylate film according to any one of (1) to (4).
(11) A liquid crystal display device comprising at least one polarizing plate including the polarizing plate according to (10) and a liquid crystal cell.
(12) The liquid crystal display device as described in (11) above, wherein the liquid crystal cell is in a VA mode or an IPS mode.

  According to the present invention, the optical anisotropy (Re, Rth) is small and substantially optically isotropic. Further, the wavelength dispersion of the optical anisotropy (Re, Rth) is small, and the axial angle is small. A cellulose acylate film having no variation is obtained. A retardation film and a polarizing plate having the above characteristics using a cellulose acylate film can be obtained. Furthermore, by using these, a liquid crystal display device having excellent viewing angle characteristics can be provided.

  The present invention is described in detail below. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Cellulose acylate film]
In the cellulose acylate film of the present invention, Re (λ) and Rth (λ) satisfy the following formulas (I) and (II).
Formula (I): 0 ≦ Re (590) ≦ 10 and | Rth (590) | ≦ 25
Formula (II): | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. ]
Actually, Re (λ) is obtained by measuring a light having a wavelength of λ nm incident on a film normal direction using a measuring device (for example, an automatic birefringence meter KOBRA 21ADH (manufactured by Oji Scientific Instruments)). be able to. Rth (λ) is a retardation value measured by incidence of light from a direction inclined by + 40 ° with respect to the normal direction of the film with Re (λ) and the in-plane slow axis as an inclination axis, and a direction inclined by −40 ° Can be calculated by calculation software attached to the measuring instrument by assuming that the average refractive index is 1.48.
In the cellulose acylate film of the present invention, the slow axis direction is 0 ° ± 10 ° or 90 ° ± 10 ° with respect to the film length direction. It is preferably 0 ° ± 7 ° or 90 ° ± 7 °, more preferably 0 ° ± 5 ° or 90 ° ± 5 °. The direction of the slow axis can be determined by using a measuring instrument (for example, KOBRA 21DH (manufactured by Oji Scientific Instruments Co., Ltd.)) and measuring the light with a wavelength of λ nm incident on the film normal direction.

[Raw material of cellulose acylate]
Examples of the cellulose raw material for the cellulose acylate film used in the present invention include cotton linter and wood pulp (hardwood pulp, softwood pulp), and any cellulose acylate obtained from any cellulose raw material can be used. Moreover, you may mix and use depending on the case. Detailed descriptions of these raw material celluloses can be found in, for example, Plastic Materials Course (17) Fibrous Resin (Maruzawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Open Technical Report 2001-1745 (page 7). To page 8) can be used, and the retardation film of the present invention is not particularly limited.

[Substitution degree of cellulose acylate]
Cellulose acylate is obtained by acylating a hydroxyl group of cellulose, and the substituent can be any acetyl group having 2 carbon atoms in the acyl group to those having 22 carbon atoms. In the cellulose acylate used in the present invention, the degree of substitution of cellulose with a hydroxyl group is not particularly limited. The degree of substitution of cellulose acylate in the present invention can be obtained by measuring the degree of binding of acetic acid and / or a fatty acid having 3 to 22 carbon atoms to be substituted for the hydroxyl group of cellulose and calculating based on the measured value. As a measuring method, it can carry out according to ASTM D-817-91. The degree of substitution when the hydroxyl group of cellulose is 100% substituted is 3.

  As described above, in the cellulose acylate used in the present invention, the substitution degree of the hydroxyl group of cellulose is not particularly limited, but the acyl substitution degree of the hydroxyl group of cellulose is preferably 2.80 to 3.00. The degree is more preferably 2.80 to 2.97, and particularly preferably 2.80 to 2.95.

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

[Degree of polymerization of cellulose acylate]
The degree of polymerization of cellulose acylate preferably used in the present invention is 180 to 700 in terms of viscosity average polymerization degree, and in cellulose acetate, 180 to 550 is more preferable, 180 to 400 is more preferable, and 180 to 350 is particularly preferable. . If the degree of polymerization is too high, the viscosity of the cellulose acylate dope solution becomes high, and film production may be difficult due to casting. Moreover, when the polymerization degree is too low, the strength of the produced film may be lowered. The viscosity-average polymerization degree can be measured by Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pages 105-120, 1962). It is also described in detail in the back of JP-A-9-95538.
Further, the molecular weight distribution of cellulose acylate preferably used in the present invention is evaluated by gel permeation chromatography, and its polydispersity index Mw / Mn (Mw is mass average molecular weight, Mn is number average molecular weight) is small, and molecular weight distribution. Is preferably narrow. The specific value of Mw / Mn is preferably 1.0 to 3.0, more preferably 1.0 to 2.0, and most preferably 1.0 to 1.6. preferable.

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

  The cellulose acylate used in the present invention may be a single or a mixture of two or more different types of cellulose acylates as long as they are within the above-described ranges such as substituent, substitution degree, polymerization degree, and molecular weight distribution.

[Additives for cellulose acylate film]
In the cellulose acylate solution for producing the cellulose acylate film in the present invention, various additives (for example, a compound that reduces optical anisotropy, a wavelength dispersion adjusting agent, an ultraviolet ray) according to the use in each preparation step are used. Inhibitors, plasticizers, deterioration inhibitors, fine particles, optical property modifiers, and the like). The addition time may be any in the dope preparation step, but may be added by adding an additive to the final preparation step of the dope preparation step.
The details of the additive are shown below.

(Compound that reduces the optical anisotropy of cellulose acylate film)
The cellulose acylate film of the present invention preferably contains at least one compound (retardation reducing compound) that lowers Re (λ) and Rth (λ) described later. The retardation-reducing compound is preferably compatible with cellulose acylate and the compound itself does not have a rod-like structure or a planar structure. Specifically, when the retardation-reducing compound has a plurality of planar functional groups such as aromatic groups, a structure having these functional groups not on the same plane but on a non-planar surface is advantageous.

From the viewpoint of solubility in cellulose acylate, the retardation reducing agent used in the present invention is preferably a compound having an octanol-water partition coefficient (log P value) of 0 to 7. A compound having a log P value of more than 7 is poor in compatibility with cellulose acylate, and tends to cause film turbidity or powder blowing. In addition, since the compound having a log P value of less than 0 has high hydrophilicity, the water resistance of the cellulose acetate film may be deteriorated. A more preferable range for the logP value is 1 to 6, and a particularly preferable range is 1.5 to 5.
The octanol-water partition coefficient (log P value) can be measured by a flask permeation method described in JIS Japanese Industrial Standard Z7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement. As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163). (1989)), Broto's fragmentation method (Eur.J.Med.Chem.-Chim.Theor., Vol. 19, p.71 (1984)), etc. are preferably used, but Crippen's fragmentation method ( J. Chem. Inf. Comput. Sci., 27, 21 (1987). When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the scope of the present invention by the Crippen's fragmentation method.

The retardation reducing compound may contain an aromatic group. The molecular weight of the retardation-reducing compound is preferably 150 to 3000, more preferably 170 to 2000, and particularly preferably 200 to 1000. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.
The retardation reducing compound is preferably liquid at 25 ° C. or a solid having a melting point of 25 to 250 ° C., more preferably liquid at 25 ° C. or a solid having a melting point of 25 to 200 ° C. is there. The retardation reducing compound is preferably not volatilized during the dope casting and drying process for producing the cellulose acylate film.
The addition amount of the retardation reducing compound is preferably 0.01 to 30% by mass of cellulose acylate, more preferably 1 to 25% by mass, and particularly preferably 5 to 20% by mass. .
The retardation-reducing compound may be used alone, or two or more compounds may be mixed and used in an arbitrary ratio.

  The average content of the retardation-reducing compound in the portion from the surface on at least one side of the cellulose acylate film to 10% of the total film thickness is the central portion in the thickness direction of the cellulose acylate film (50% of the total film thickness). It is preferable that it is 80 to 99% of the average content rate of this compound in (part). The abundance of the retardation-reducing compound can be determined by measuring the amount of the compound at the surface and in the center by, for example, a method using an infrared absorption spectrum described in JP-A-8-57879.

  Although the specific example (compound represented by General formula (1) or (2)) of the retardation decreasing compound of a cellulose acylate film used preferably by this invention is shown below, this invention is limited to these compounds. It is not a thing.

In the general formula (1), R ¹¹ represents an alkyl group or an aryl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Further, it is particularly preferable that the total number of carbon atoms of R ¹¹ , R ¹² and R ¹³ is 10 or more.

R ^{11 to} R ¹³ may have a substituent, and as the substituent, a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are preferable, and an alkyl group, an aryl group, Alkoxy groups, sulfone groups and sulfonamido groups are particularly preferred.

In general formula (1), the alkyl group represented by R ^{11 to} R ¹³ may be linear, branched, or cyclic. The alkyl has preferably 1 to 25 carbon atoms, more preferably 6 to 25 carbon atoms, and particularly preferably 6 to 20 carbon atoms. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t -Ethyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl and the like.

In general formula (1), the aryl group represented by R ^{11 to} R ¹³ preferably has 6 to 30 carbon atoms, and particularly preferably has 6 to 24 carbon atoms. Examples of the aryl group include groups such as phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, and triphenylphenyl. Although the preferable example (compound (101)-(164)) of a compound represented by General formula (1) below is shown, this invention is not limited to these specific examples.

General formula (2)

In the general formula (2), R ³¹ represents an alkyl group or an aryl group, and R ³² and R ³³ each independently represent a hydrogen atom, 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.

In the general formula (2), the alkyl group and aryl group represented by R ^{31 to} R ³³ may have a substituent. Examples of the substituent include a halogen atom (eg, chlorine, bromine, fluorine and iodine), alkyl group, aryl group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, sulfonyl Amino group, hydroxy group, cyano group, amino group, and acylamino group are preferred, halogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, sulfonylamino group, and acylamino group are more preferred, alkyl group, aryl group, A sulfonylamino group and an acylamino group are particularly preferred.

  Although the preferable example (compound 301-393) of a compound represented by General formula (2) below is shown below, this invention is not limited to these specific examples.

(Wavelength dispersion adjusting agent)
The cellulose acylate film in the invention can contain a compound for adjusting wavelength dispersion. The compound for adjusting the wavelength dispersion will be described. In order to bring the Rth wavelength dispersion of the cellulose acylate film used in the present invention close to zero in the entire visible light range, a compound that reduces the Rth wavelength dispersion ΔRth = | Rth (400) −Rth (700) | It is preferable to contain at least one kind of “wavelength dispersion adjusting agent”.

The chromatic dispersion adjusting agent preferably has absorption in the ultraviolet region of 200 nm to 400 nm.
In general, Re and Rth values of cellulose acylate film have a dispersion characteristic that is larger on the long wavelength side than on the short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 nm to 400 nm has a wavelength dispersion characteristic in which the absorbance on the long wavelength side is larger than that on the short wavelength side. Therefore, wavelength dispersion can be smoothed by increasing Re and Rth on the short wavelength side of the cellulose acylate film with a compound having an appropriate ultraviolet absorption.

  The in-plane variation of chromatic dispersion affects the variation of optical performance, particularly the color viewing angle characteristics. Therefore, the wavelength dispersion adjusting agent is required to be sufficiently uniformly compatible with cellulose acylate. The absorption band range in the ultraviolet region of such a wavelength dispersion adjusting agent is preferably 200 nm 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 preferable 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 260 to 800, still more preferably 270 to 800, Especially 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.

  The added amount of the wavelength dispersion adjusting agent preferably used in the present invention described above is preferably 0.01 to 30% by mass, and preferably 0.1 to 20% by mass with respect to the solid content of cellulose acylate. More preferably, it is especially preferable that it is 0.2-10 mass%.

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 present invention is not limited to these compounds.

  As the benzotriazole-based compound used as the wavelength dispersion adjusting agent, a compound represented by the following general formula (3) is preferably used as the wavelength dispersion adjusting agent of the present invention.

Formula ^{(3): Q 1 -Q 2} -OH
(In the formula, Q ¹ represents a nitrogen-containing aromatic heterocycle, and Q ² represents an aromatic ring.)

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

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.
The aromatic hydrocarbon ring is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring or a naphthalene ring), more preferably 6 to 20 carbon atoms. Of the aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms, and particularly preferably a benzene ring.

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

  Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert- And each group such as butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.); an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, Particularly preferably, it has 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, 2-butenyl, 3-pentenyl, etc.); alkynyl group (preferably 2 to 20 carbon atoms, more preferably 2 carbon atoms) To 12 and particularly preferably 2 to 8 carbon atoms, for example, groups such as propargyl and 3-pentynyl); aryl groups (preferably Or 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl, and the like. A substituted 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, amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc. An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy and the like). An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, Oxy include the groups such as 2-naphthyloxy).;

  An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl groups); alkoxy A carbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonyl and ethoxycarbonyl groups); aryloxycarbonyl Group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl group); acyloxy group (preferably having 2 carbon atoms) To 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as an acetoxy group Benzoyloxy group, etc.); acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetylamino group, benzoylamino group, etc. An alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group). Aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, such as phenyloxycarbonylamino group); Group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably A prime number 12, for example, methanesulfonylamino group, and benzenesulfonylamino group).;

  Sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc. Carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl) And alkylthio groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. For example, each group such as methylthio and ethylthio is Arylthio group (preferably having 6 to 20 carbon atoms, more preferably A prime number of 6 to 16, particularly preferably a carbon number of 6 to 12, such as a phenylthio group, and the like; a sulfonyl group (preferably having a carbon number of 1 to 20, more preferably a carbon number of 1 to 16, and particularly preferably carbon). And a sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, each group such as methanesulfinyl, benzenesulfinyl, etc.); a ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, ureido , Methylureido, phenylureido, etc.); phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably charcoal) 1 to 16, particularly preferably 1 to 12 carbon atoms, and examples thereof include groups such as diethyl phosphoric acid amide and phenyl phosphoric acid amide); hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine) 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 atom) And the hetero atom includes, for example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, and the like. Silyl group (preferably having 3 to 40 carbon atoms, more preferably carbon 3-30, particularly preferably 3-24 carbon atoms, and examples thereof include trimethylsilyl group and triphenylsilyl group). These substituents T may be further substituted with a substituent. 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.

  The compound represented by the general formula (3) is preferably a compound represented by the following general formula (3-A).

(In the general formula (3-A), 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.)

In general formula (3-A), 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, As the substituent, the above-described substituent T can be applied. 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 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 a C1-12 alkyl group, particularly preferably a C1-12 alkyl group (preferably Is carbon number 4-12).

In general formula (3-A), 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, or a hydroxy group. A halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, or a halogen atom, still more preferably a hydrogen atom or a carbon 1-12 alkyl group, particularly preferably a hydrogen atom. An atom or a methyl group, and most preferably a hydrogen atom.

In general formula (3-A), R ⁵ and R ⁸ 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, or a hydroxy group. A halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, or a halogen atom, still more preferably a hydrogen atom or a carbon 1-12 alkyl group, particularly preferably a hydrogen atom. An atom or a methyl group, and most preferably a hydrogen atom.

In general formula (3-A), 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, or a hydroxy group. A halogen atom, more preferably a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an aryloxy group or a halogen atom, still more preferably a hydrogen atom or a halogen atom, particularly preferably a hydrogen atom or a chlorine atom. It is.

  The compound represented by the general formula (3) is more preferably a compound represented by the following general formula (3-B).

(In general formula (3-B), R ¹ , R ³ , R ⁶ and R ⁷ have the same meanings as in general formula (3-A), and preferred ranges are also the same.)

  Specific examples of the compound represented by formula (3-B) (compounds UV1 to UV23) are shown below, but the present invention is not limited to the following specific examples.

  Among the above-mentioned benzotriazole compounds (wavelength dispersion adjusting agents), when a cellulose acylate film is produced without containing a molecular weight of 320 or less, it is preferable in terms of retention.

  Moreover, as a benzophenone type compound which is one of the wavelength dispersion adjusting agents used in the present invention, a compound represented by the following general formula (4) can also be preferably used.

(In General Formula (4), Q ¹ and Q ² each independently represent an aromatic ring. X represents NR (R: hydrogen atom or substituent), oxygen atom or sulfur atom.)

In the general formula (4), 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 a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring or a naphthalene ring), more preferably 6 to 6 carbon atoms. 20 is an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms, and particularly preferably a benzene ring.
The aromatic heterocycle 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. , Quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene and the like. Preferable aromatic heterocycles are pyridine, triazine, and quinoline.

The aromatic ring represented by Q ¹ and Q ² in the general formula (4) is preferably an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms, and further preferably a substituted ring. Or it is an unsubstituted benzene ring.
Q ¹ and Q ² in the general formula (4) may further have a substituent, and a substituent T ¹ described later is preferable, but the substituent includes a carboxylic acid group, a sulfonic acid group, or a quaternary ammonium group. There is nothing. Further, if possible, substituents may be linked to form a ring structure.

In the general formula (4), X represents NR (R represents a hydrogen atom or a substituent. Substituent T ¹ described later can be applied as the substituent), an oxygen atom or a sulfur atom. X is preferably NR (preferably R is an acyl group or a sulfonyl group, and these substituents may be further substituted), or O, and particularly preferably O.

Examples of the substituent T ¹ include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, and each group such as tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.); an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 2 carbon atoms). 12, particularly preferably having 2 to 8 carbon atoms, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.); alkynyl group (preferably having 2 to 20 carbon atoms, more preferably carbon 2 to 12, particularly preferably 2 to 8 carbon atoms, such as a propargyl group and a 3-pentynyl group)); an aryl group (Preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like.) An unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino) An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms. For example, each group such as methoxy, ethoxy, butoxy, etc. Aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms). A phenyloxy group, a 2-naphthyloxy group, etc.); an acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms; , Benzoyl, formyl, pivaloyl, etc.));

An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonyl group and an ethoxycarbonyl group); aryloxycarbonyl Group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl group); acyloxy group (preferably having 2 carbon atoms) -20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, for example, an acetoxy group, a benzoyloxy group, etc.); an acylamino group (preferably 2 to 20 carbon atoms, more preferably Has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetylamino group, benzo An alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group). Aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, such as phenyloxycarbonylamino group) A sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methanesulfonylamino group and a benzenesulfonylamino group); Sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably having 0 to 16 carbon atoms, especially Mashiku is 0-12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and each group such as phenylsulfamoyl).;

A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like. Alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methylthio and ethylthio groups); arylthio group ( Preferably it has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenylthio group, etc.); a sulfonyl group (preferably 1 to 20 carbon atoms, more Preferably it is C1-C16, Most preferably, it is C1-C12, for example, a mesyl group, a tosyl group, etc. A sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methanesulfinyl group, a benzenesulfinyl group, etc.). ;

A ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include ureido, methylureido, phenylureido and the like); phosphorus Acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide group and phenyl phosphoric 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; A cyclic 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 and oxygen Children, sulfur atoms, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc. groups; silyl groups (preferably having 3 carbon atoms) To 40, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl groups). These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  As the compound represented by the general formula (4), a compound represented by the following general formula (4-A) is preferable.

(In general formula (4-A), 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 1 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, or a halogen atom, more preferably a hydrogen atom or a carbon atom. 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, and more preferably an alkoxy group having 1 to 20 carbon atoms. Group, particularly preferably an alkoxy group having 1 to 12 carbon atoms.

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

  The compound represented by the general formula (4) is more preferably a compound represented by the following general formula (4-B).

(In the general formula (4-B), 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. To express.)

In general formula (4-B), 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. As the group, the above-described substituent T can be applied.
R ¹⁰ is preferably a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group having 5 to 20 carbon atoms, and still more preferably a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms. (Including n-hexyl group, 2-ethylhexyl group, n-octyl group, n-decyl group, n-dodecyl group, benzyl group, etc.), particularly preferably a substitution of 6 to 12 carbon atoms or 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 (4) can be synthesized by a known method described in JP-A-11-12219.
Specific examples of the compound represented by the general formula (4) (compounds UV-101 to UV-121) are shown below, but the present invention is not limited to the following specific examples.

  Moreover, as a compound containing the cyano group which is one of the wavelength dispersion regulators used for this invention, the compound represented by General formula (5) is used preferably.

General formula (5):

(In the general formula (5), Q ¹ and Q ² each independently represents an aromatic ring. X ¹ and X ² represent a hydrogen atom or a substituent, and at least one of them represents a cyano group, a carbonyl group, or a sulfonyl group. Represents a group or an aromatic heterocycle.)

The aromatic ring represented by Q ¹ and Q ² in the general formula (5) may be an aromatic hydrocarbon ring or an aromatic heterocycle. These may be monocyclic or may form a condensed ring with another ring.

(Fine particles)
It is preferable to add fine particles as a matting agent to the cellulose acylate film in the 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 silicon dioxide fine particles preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more. A primary particle having an average diameter as small as 5 to 16 nm is more preferable because the haze of the film can be lowered. The apparent specific gravity of the silicon dioxide is more preferably 90 to 200 g / liter or more, and particularly preferably 100 to 200 g / liter or more. A larger apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.

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

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

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

In order to obtain a cellulose acylate film having particles having a small secondary average particle size in the present invention, several methods are conceivable when preparing a fine particle dispersion. For example, a fine particle dispersion prepared by stirring and mixing a solvent and fine particles is prepared in advance, and this fine particle dispersion is added to a small amount of cellulose acylate solution separately prepared, stirred and dissolved, and further mixed with the main cellulose acylate dope solution. There is a way. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are more difficult to reaggregate. In addition, after adding a small amount of cellulose ester to the solvent and dissolving with stirring, add the fine particles to this and disperse with a disperser, and use this as a fine particle additive solution. The method of mixing is also mentioned. 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, and butyl alcohol. Solvents other than the lower alcohol are not particularly limited, but it is preferable to use a solvent used at the time of film formation of the cellulose ester.

(Plasticizer, degradation inhibitor, release agent)
In the cellulose acylate film of the present invention, in addition to the above-mentioned retardation reducing compound and wavelength dispersion adjusting agent, various additives (for example, a plasticizer, an ultraviolet ray preventing agent, a deterioration preventing agent) depending on the use in each preparation step. , Release agents, infrared absorbers, etc.), which can be solid or oily. That is, these additives are not particularly limited in terms of their melting points and boiling points. For example, mixing of an ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, or similarly, mixing of a plasticizer is described in, for example, JP-A-2001-151901. Furthermore, the infrared absorbing dye is described in, for example, JP-A No. 2001-194522. The additive may be added at any time in the dope preparation step, but may be added to the final preparation step of the dope preparation step by adding the preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is formed in a multilayer, the kind and addition amount of the additive of each layer may differ. These additives are described in, for example, Japanese Patent Application Laid-Open No. 2001-151902, and these are conventionally known techniques. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

  In the cellulose acylate film used in the present invention, the total amount of compounds having a molecular weight of 3000 or less is preferably 5 to 45% by mass, more preferably 10 to 40% by mass, based on the cellulose acylate mass. More preferably, it is 15-30 mass%. As described above, these compounds include retardation reducing compounds, wavelength dispersion adjusting agents, ultraviolet ray preventing agents, plasticizers, deterioration preventing agents, fine particles, release agents, infrared absorbers, etc., and the molecular weight is 3000 or less. Preferably, 2000 or less is more preferable, and 1000 or less is more preferable. When the total amount of these compounds is 5% by mass or less, the properties of cellulose acylate alone are likely to be obtained, and there are problems such as that the optical performance and physical strength are likely to vary with changes in temperature and humidity. There is a case. Further, when the total amount of these compounds is 45% or more, there are problems such as exceeding the limit of compatibility of the compounds in the cellulose acylate film and depositing on the film surface to cause the film to become cloudy (crying out of the film). May be more likely to occur.

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

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

  In addition, the solvent for the cellulose acylate solution and film used in the present invention is disclosed in the following documents including the dissolution method, and the preferred embodiments are also the same. They are, for example, JP-A No. 2000-95876, JP-A No. 12-95877, JP-A No. 10-324774, JP-A No. 8-152514, JP-A No. 10-330538, and JP-A No. 9-95538. JP-A-9-95557, JP-A-10-235664, JP-A-12-63534, JP-A-11-21379, JP-A-10-182853, JP-A-10-278056, JP-A-10 -297702, JP-A-10-323853, JP-A-10-237186, JP-A-11-60807, JP-A-11-152342, JP-A-11-292988, JP-A-11-60752. No. 1, JP-A-11-60752, and the like. According to these documents, not only the preferable solvent for the cellulose acylate in the present invention but also the physical properties of the solution and the coexisting substances to be coexisted are described, which is also a preferable embodiment in the present invention.

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

(Casting process)
Next, a method for producing a film using the cellulose acylate solution in the present invention will be described. The method and equipment for producing a cellulose acylate film in the present invention can use a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film. 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 fed from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations. The dry-dried dope film (also referred to as a web) is peeled off from the metal support at the peeling point which is uniformly cast on the metal support and the metal support has almost gone around.
The step of casting on the support is preferably covered with a certain space and a nitrogen atmosphere. The optimum temperature can be selected depending on the film forming method. The amount of residual solvent contained in the web at the time of peeling defined by the following formula (III) varies depending on the casting method, and 40% to 80% if it is a general method in which the dope surface temperature is close to room temperature. % Is preferable, 45% to 75% is more preferable, and 50% to 70% is most preferable. In the cooling casting method in which the dope surface temperature is set to 10 ° C. or less, the casting is preferably 100% to 300%, more preferably 130% to 270%, and most preferably 150% to 250%. preferable. The cooling casting can be performed, for example, by the method disclosed in JP-A-62-115035.
Formula (III): Residual solvent amount at stripping = (film weight at stripping−film weight at zero residual solvent amount) / film weight at zero residual solvent amount × 100

(Drying process)
In the present invention, both ends of the web obtained in the casting process are held, and the tenter's expansion / contraction width and temperature are adjusted so that tension can be applied, and the web is transported and dried. The tenter shape is not particularly limited as long as it satisfies the claims of the present invention, and a method of applying tension by holding both ends of the film with clips, a method of fixing both ends of the film with pins, and the like can be used.
In the cellulose acylate film of the present invention, the tenter tension is adjusted to 10 to 50 kgf / m (98 to 490 N / m) in order to achieve the object. 10 to 40 kgf / m (98 to 392 N / m) is more preferable, and 15 to 40 kgf (147 to 392 N / m) is most preferable. If it exceeds 50 kgf / m (490 N / m), even if it is the prescription of this invention, a phase difference will generate | occur | produce and it will become impossible to achieve the target optical performance.
Generally, in the process at the initial stage of drying, shrinkage occurs due to the volatilization of solvent. Accordingly, if the tension is applied, the tenter width may be narrower than the width of the tenter entrance. The expansion / contraction width of the tenter is preferably 90% to 110%, more preferably 95% to 107%, most preferably 97% to 105%, where the width of the tenter entrance is 100%. preferable. Since the drying temperature of the tenter part varies depending on the casting method, an optimal temperature is appropriately selected. In the case of a normal casting method, the temperature is preferably 70 ° C to 130 ° C, more preferably 80 ° C to 120 ° C, and most preferably 80 ° C to 110 ° C. When the cooling casting method is used, it is preferably 40 ° C. to 120 ° C., more preferably 40 ° C. to 110 ° C., and most preferably 50 ° C. to 105 ° C. The temperature may be set with a gradient in the length direction of the tenter part. Although there is no restriction | limiting in particular in a heating method, The method of introduce | transducing the wind set to predetermined temperature into a tenter part is forced compulsorily. In order to reduce in-plane variations in the slow axis direction, a wind control plate may be provided, or a known method such as a back heater may be used.

  The residual solvent amount when applying tension with a tenter is preferably 10% or more. More preferably, it is 12% or more, and most preferably 15% or more. When tension is applied with a residual solvent amount of 10% or less, the axial variation may not be reduced.

The cellulose acylate film of the present invention may be held in the tenter until the residual solvent amount becomes zero as much as possible, but from the viewpoint of productivity, the film was detached from the tenter during drying and was held by the tenter clip. After cutting off both ends, it is desirable to finish drying while mechanically transporting in a drying section composed of a plurality of roll groups. “To finish drying” may be a residual solvent amount of 1% or less. The amount of residual solvent in the film when it leaves the tenter is preferably 15% or more and 40% or less, more preferably 17% or more and 37% or less, and most preferably 17% or more and 35% or less. When peeling from the tenter while maintaining a residual solvent amount of 40% or more, the film is easily stretched in the length direction of the film with the necessary transport tension for the subsequent drying process, and adjustment to achieve the desired optical performance is performed. It becomes difficult. Moreover, in order to lower it to 15% or less, it is necessary to slow down the conveying speed or lengthen the tenter part, which is not desirable in terms of productivity.
The conveying tension to the drying section is preferably 2 kgf / m to 20 kgf / m (19.6 N / m to 196 N / m) per film width, and preferably 2 kgf / m to 18 kgf / m (19.6 N / m to 176 N / m). More preferably, it is most preferably 2 kgf / m to 16 kgf / m (19.6 N / m to 167 N / m). If it is 2 kgf / m (19.6 N / m) or less, sagging of the film, wrinkles, rubbing in a roll shape and the like are likely to occur, and the surface state is deteriorated. If it is 20 kgf / m (196 N / m) or more, particularly when the amount of residual solvent is large, it is difficult to achieve the target optical performance by stretching in the transport direction.

  The drying temperature after releasing the holding of both ends of the film is preferably 100 to 150 ° C, more preferably 100 ° C to 140 ° C, and most preferably 110 ° C to 140 ° C. When the temperature is lower than 100 ° C., it is difficult to proceed with drying, and at the same time, it is difficult to reduce Rth. On the other hand, when the temperature is 150 ° C. or higher, the glass transition temperature of the film is often exceeded, and the film may be stretched in the length direction to cause a phase difference. Further, depending on the type of additive, there is a possibility that it will be slightly volatilized in the drying system. Here, the drying temperature is the temperature when a sensor such as a thermocouple is attached to the film being dried, but when using the method of introducing heated air to dry, the temperature of the air supply port and the exhaust port Management by temperature In general, the supply air temperature is higher than the film surface temperature, and the exhaust temperature is the same as or slightly lower than the film surface temperature, and therefore, the temperature is controlled within the temperature range that satisfies the above film surface temperature. When a method of heating using radiant heat is used, measurement is performed using a fixed sensor near the film surface.

The film after drying is wound up to a predetermined length in a roll by a winder. You may provide the curl improvement part etc. by steam immediately before winding.
In the solution casting film forming method used for the functional protective film which is an optical member for an electronic display, which is the main use of the cellulose acylate film in the present invention, in addition to the solution casting film forming apparatus, the subbing is performed. In many cases, a coating apparatus is added for surface processing of a film such as a layer, an antistatic layer, an antihalation layer, or a protective layer. These are described in detail on pages 25 to 30 of the Japan Society for Invention and Technology (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society for Invention), and can be preferably used as appropriate in the present invention. it can.

  10-120 micrometers is preferable, as for the thickness of the cellulose acylate film produced as mentioned above, 20-100 micrometers is more preferable, and 30-90 micrometers is further more preferable. The residual solvent amount of the film is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less.

[Evaluation method of cellulose acylate film]
The cellulose acylate film in the present invention was evaluated by the following method.

(In-plane retardation Re (λ) and thickness direction retardation Rth (λ))
A sample 30 mm × 40 mm was conditioned for 2 hours at 25 ° C. and a relative humidity of 60%, and Re (λ) was a film method using light with a wavelength of λ nm in an automatic birefringence meter “KOBRA 21ADH” (manufactured by Oji Scientific Instruments). Measurements were made by entering in the line direction. Rth (λ) is a light having a wavelength of λ nm by re-inclining the test sample up to 50 ° every 10 ° with Re (λ) and the in-plane slow axis as the tilt axis and the film normal direction as 0 °. Was calculated by inputting an assumed value of the average refractive index of 1.48 and a film thickness on the basis of the retardation value measured by making the light incident.

(Measurement of wavelength dispersion of Re (λ) and Rth (λ))
A sample 30 mm × 40 mm was conditioned for 2 hours at 25 ° C. and a relative humidity of 60%, and light with a wavelength of 780 nm to 380 nm was incident in the normal direction of the film on an ellipsometer “M-150” (manufactured by JASCO Corporation). Thus, Re (λ) at each wavelength was obtained, and the wavelength dispersion of Re (λ) was measured. As for the wavelength dispersion of Rth (λ), light having a wavelength of 780 nm to 380 nm is incident from the direction inclined by + 40 ° with respect to the normal direction of the film with Re (λ) as the slow axis in the plane as the tilt axis And a retardation value measured by allowing light having a wavelength of 780 to 380 nm to enter from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis. Based on the retardation values measured in three directions, an assumed average refractive index of 1.48 and a film thickness were input and calculated.

(Measurement of slow axis direction of cellulose acylate film)
A 70 mm × 110 mm sample was cut out, conditioned for 2 hours at a relative humidity of 60%, and the slow axis direction was measured with an automatic birefringence meter (KOBRA 21DH, manufactured by Oji Scientific Instruments). The sample was divided into 13 parts by dividing the entire width equally to obtain variation.

[Surface treatment of cellulose acylate film]
The cellulose acylate film may optionally be subjected to a surface treatment to improve the adhesion between the cellulose acylate film and each functional layer (for example, the undercoat layer and the back layer). 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 is a treatment for subjecting the film surface to a plasma treatment in the presence of a plasma-excitable gas.
The glow discharge treatment includes a low temperature plasma treatment performed under a low pressure gas of 10 ^{−3 to} 20 Torr (0.13 to 2700 Pa). Plasma treatment under atmospheric pressure is also a preferred glow discharge treatment. The plasma-excitable gas refers to a gas that is plasma-excited under the above-described conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. Can be mentioned. Details of these are described in detail on pages 30 to 32 of the Japan Society for Invention and Innovation Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society for Invention) and are preferably used in the present invention. Can do.

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

(Optically anisotropic layer)
The retardation film used in the present invention may be provided with at least one optically anisotropic layer on the above polymer film. The optically anisotropic layer to be provided is not particularly limited, and may be another polymer film or a layer in which the alignment state is fixed after the liquid crystal compound is aligned. There is no restriction | limiting in particular also about the method of providing an optically anisotropic layer, It can provide by generally well-known methods, such as the apply | coating method, a vapor deposition method, and the transfer method. When the transfer method is used, an adhesive layer may be provided between the polymer film and the retardation film.
When an optically anisotropic layer is provided by applying a liquid crystal compound, an alignment film layer may be provided between the optically anisotropic layer and the polymer film in order to control the alignment state. The alignment film material and the control method are not particularly limited as long as the problems of the polymer film of the present invention can be achieved, and known materials and methods can be used. In particular, when a cellulose acylate film is used as the polymer film, a “rubbing method” in which an alignment film layer of polyvinyl alcohol is provided and the surface is rubbed to control the alignment, or a photo-alignment film is provided for UV light treatment. The “photo-alignment method” or the like for controlling the orientation with can be preferably used.
The alignment fixing of the liquid crystal compound is not particularly limited as long as there is no change in optical performance in the temperature range in which the liquid crystal panel can be used, but after aligning the liquid crystal compound having a bonding group at the end of the liquid crystal compound, It is desirable to bond and fix by a method such as UV irradiation.
The thickness of the optically anisotropic layer is preferably 100 μm or less, more preferably 80 μm or less, and most preferably 50 μm or less.

[Polarizer]
The cellulose acylate film and retardation film of the present invention are particularly useful as a transparent protective film for polarizing plates. A method for manufacturing the polarizing plate is not particularly limited, and the polarizing plate can be manufactured by a general method. That is, both sides of a polarizer prepared by subjecting a retardation film made of a cellulose acylate film or a cellulose acylate film provided with an optically anisotropic layer to an alkali treatment and immersing and stretching a polyvinyl alcohol film in an iodine solution. There is a method of bonding 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 laminating the cellulose acylate 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 transparent protective film that protects both sides of the polarizer (at least one is the cellulose acylate film or retardation film of the present invention), and further has a protective film on one surface of the polarizing plate, A separate film is bonded to the opposite 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.
In a liquid crystal display device, a substrate containing liquid crystal is usually disposed between two polarizing plates. However, a polarizing plate to which the cellulose acylate film or retardation film of the present invention is applied may be provided only on one side of the liquid crystal cell. It may be provided on both sides.
The polarizing plate protective film on the outermost surface of the liquid crystal display device is preferably provided with at least one of a (transparent) hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer and an antifouling layer. The display quality and surface characteristics to be selected can be appropriately selected and provided.

(Configuration of liquid crystal display device)
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. It has the structure which has arrange | positioned retardation film. In this invention, the cellulose acylate film of this invention is included in the part of retardation film.
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 and retardation film of the present invention can be used for liquid crystal cells of 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. There has also been proposed a display mode in which the display mode is orientation-divided. The cellulose acylate film and the retardation film of the present invention are 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 or retardation film of the present invention can be used as an optical compensation sheet for a TN liquid crystal display device having a TN mode liquid crystal cell. 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. Further, it is described in a paper by Mori et al. (Jpn. J. Appl. Phys. 36 (1997) 143, Jpn. J. Appl. Phys. 36 (1997) 1068).

(STN type liquid crystal display device)
The cellulose acylate film or retardation film of the present invention can be used as an optical compensation sheet for an STN type liquid crystal display device having an STN mode liquid crystal cell. 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 or retardation film in the present invention can be used as a support for an optical compensation sheet or a sheet itself of a VA liquid crystal display device having a VA mode liquid crystal cell. The optical compensation sheet used in the VA liquid crystal display device preferably has a Re retardation value of 0 to 150 nm and an Rth retardation value of 70 to 400 nm. The Re retardation value is more preferably 20 to 70 nm. When two optically anisotropic polymer films are used in the 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 is particularly advantageously used as a support for an optical compensation sheet of an IPS liquid crystal display device and an ECB liquid crystal display device having IPS mode and ECB mode liquid crystal cells, or as a protective film for a polarizing plate. It is done. 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 in the present invention contributes to the improvement of the tint, the expansion of the viewing angle, and the improvement of the contrast. In this embodiment, the cellulose acylate film of the present invention is used for the protective film (the protective film on the cell side) disposed between the liquid crystal cell and the polarizing plate among the protective films of the polarizing plates above and below the liquid crystal cell. It is preferable to use the polarizing plate at least on one side. More preferably, an optically anisotropic layer is disposed between the protective film of the polarizing plate and the liquid crystal cell, and the retardation value of the disposed optically anisotropic layer is twice the value of Δn · d of the liquid crystal layer. It is preferable to set as follows.

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

[Composition of cellulose acylate solution A]
Cellulose acylate having a degree of acetylation of 2.94 100.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass

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

[Composition of matting agent solution A]
-Silica particle dispersion liquid with an average particle diameter of 16 nm 10.0 parts by mass-Methylene chloride (first solvent) 76.3 parts by mass-Methanol (second solvent) 3.4 parts by mass-Cellulose acylate solution A 10.3 parts by mass Part

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution. The following compounds were used as the compound that reduces the optical anisotropy and the wavelength dispersion adjusting agent.

(Additive solution composition)
-Retardation-reducing compound 49.3 parts by weight-Wavelength dispersion adjusting agent 7.6 parts by weight-Methylene chloride (first solvent) 58.4 parts by weight-Methanol (second solvent) 8.7 parts by weight-Cellulose reed Rate solution A 12.8 parts by mass

(Preparation of cellulose acylate film 1)
94.6 parts by mass of the cellulose acylate solution A, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the additive solution were mixed after filtration, and cast using a band casting machine. did. In the composition, the mass ratio of the retardation reducing compound and the wavelength dispersion modifier to cellulose acylate was 11.7% and 1.2%, respectively.
The film was peeled from the band with a residual solvent amount of 55%, and dried at 95 ° C. while applying a tension of 18 kgf / m (176 N / m) in a tenter zone where both ends of the film were held by clips. At this time, the maximum expansion / contraction rate with respect to the tenter entrance was 103%. When the residual solvent amount was 20 to 22%, the film was removed from the tenter clip, and the end was cut off with a cutter blade. Next, the film was dried while being transported to a drying zone composed of a plurality of roll groups with a transport tension of 11 kgf / m (108 N / m). The drying temperature was 100 ° C to 135 ° C. After cutting the both ends of the obtained film with a cutter blade to obtain a width of 1340 mm, a knurling for preventing winding deviation was provided at both ends, and a 2600 m length was wound up in a roll shape to prepare a cellulose acylate film 1. As a result of examining the residual solvent amount of the obtained film, it was 0.3%. The film thickness was 80 μm.
A sample with a size of 3 cm × 4 cm was cut out from the obtained film, Re (590), Rth (590), their wavelength dispersion, and the direction of the slow axis in the above-mentioned item (cellulose acylate evaluation method). It was measured by the method described. The results are shown in Table 1.

[Example 2]
(Preparation of cellulose acylate film 2)
The dope produced in Production Example 1 was used for casting with a band casting machine. After peeling off the film with a residual solvent amount of 70%, the film was dried at 95 ° C. while applying a tension of 16 kgf / m (157 N / m) in a tenter zone where both ends of the film were held with clips. A cellulose acylate film 2 was produced in the same manner as in Production Example 1 except that the residual solvent amount was 25% and the carrier was separated from the tenter and the conveyance tension was set to 8 kgf / m (78 N / m). As a result of examining the residual solvent amount of the obtained film, it was 0.4%. The film thickness was 80 μm.
The optical performance of the obtained film was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 3]
(Preparation of cellulose acylate film 3)
The flow rate of the dope used in Production Example 1 was adjusted, and the resulting film was cast so that the film thickness was 65 μm. After peeling off the film with a residual solvent amount of 60%, the film was dried at 90 ° C. while applying a tension of 15 kgf / m (147 N / m) in a tenter zone where both ends of the film were held with clips. The cellulose acylate film 3 was removed in the same manner as in Production Example 1 except that the residual solvent amount was 20% and the tenter was removed, the conveyance tension was 9 kgf / m (88 N / m), and the winding length was 3900 m. Produced. As a result of examining the residual solvent amount of the obtained film, it was 0.2%.
The optical performance of the obtained film was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 4]
(Preparation of cellulose acylate film 4)
The flow rate of the dope used in Production Example 1 was adjusted, and casting was performed so that the film thickness of the obtained film was 40 μm. After peeling off the film with a residual solvent amount of 55%, the film was dried at 90 ° C. while applying a tension of 15 kgf / m (147 N / m) in a tenter zone where both ends of the film were held with clips. The cellulose acylate film 4 was removed in the same manner as in Production Example 1 except that the residual solvent amount was 20% and the tenter was removed, the conveyance tension was 10 kgf / m (98 N / m), and the winding length was 3900 m. Produced. As a result of examining the residual solvent amount of the obtained film, it was 0.1%.
The optical performance of the obtained film was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 5]
(Preparation of cellulose acylate film 5)
A cellulose acylate film 5 was produced in the same manner as in Production Example 1 except that the finished width of the film was adjusted to 1475 mm. The optical performance of the obtained film was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 6]
(Preparation of cellulose acylate film 6)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution B.

[Cellulose acylate solution B composition]
Cellulose acylate having an acetylation degree of 2.96 100.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass

(Preparation of matting agent solution B)
A matting agent solution B was prepared in the same manner as in the preparation of the matting agent solution A in Production Example 1, except that the cellulose acylate solution A was changed to the cellulose acylate solution B.

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution. The same compounds as in Production Example 1 were used as the retardation reducing compound and the wavelength dispersion adjusting agent.

[Additive solution composition]
-Retardation-reducing compound 54.0 parts by mass-Wavelength dispersion adjusting agent 7.6 parts by mass-Methylene chloride (first solvent) 58.4 parts by mass-Methanol (second solvent) 8.7 parts by mass-Cellulose acetate Solution B 12.8 parts by mass

94.6 parts by mass of the cellulose acetate solution B, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the additive solution were mixed after filtration, and cast using a band casting machine. did. In the composition, the mass ratio of the retardation reducing compound and the wavelength dispersion adjusting agent to cellulose acetate was 16.0% and 1.2%, respectively.
The produced dope was cast with a band casting machine. After peeling off the film with a residual solvent amount of 45%, it was dried at 95 ° C. while applying a tension of 35 kgf / m (343 N / m) in a tenter zone in which both ends of the film were held with clips. A cellulose acylate film 6 was produced in the same manner as in Production Example 1 except that the residual solvent amount was released from the tenter at a stage of 27% and the conveying tension was 10 kgf / m (10 N / m). As a result of examining the residual solvent amount of the obtained film, it was 0.3%. The film thickness was 80 μm.
The optical performance of the obtained film was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 7]
(Preparation of cellulose acylate film 7)
A cellulose acylate film 7 was produced in the same manner as in Example 1 except that the conveyance speed was decreased and the film was held with a tenter when the residual solvent amount was 6% and tension was applied. The optical performance was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Example 8]
(Preparation of cellulose acylate film 8)
A cellulose acylate film 8 was produced in the same manner as in Example 1 except that the residual solvent amount at the time of leaving the tenter was 50%. The optical performance was evaluated in the same manner as in Production Example 1. The results are shown in Table 1.

[Comparative Example 1]
(Preparation of cellulose acylate film 9)
A cellulose acylate film 9 was produced in the same manner as in Example 1 except that the tension in the width direction of the tenter was 60 kgf / m (588 N / m). About the obtained film, it carried out similarly to Example 1, and evaluated optical performance. The results are shown in Table 1.

[Comparative Example 2]
(Preparation of cellulose acylate film 10)
A cellulose acylate film 10 was produced in the same manner as in Production Example 1 except that the tension in the width direction of the tenter was 2 kgf / m (19.6 N / m). The optical performance of the obtained film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
(Preparation of cellulose acylate film 11)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution.

[Cellulose acylate solution composition]
Cellulose acylate having an acetylation degree of 2.87 100.0 parts by mass Triphenyl phosphate 7.8 parts by mass Biphenyl diphenyl phosphate 3.9 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol ( Second solvent) 60.0 parts by mass

  98.6 parts by mass of the cellulose acylate solution A and 1.4 parts by mass of the matting agent solution were mixed after filtration, and cast using a band casting machine in the same manner as in Example 1. An acylate film 11 was produced. About the obtained film, it carried out similarly to Example 1, and evaluated optical performance. The results are shown in Table 1.

[Comparative Example 4]
(Preparation of cellulose acylate film 12)
A cellulose acylate film 12 was produced in the same manner as in Comparative Example 3 except that the tension in the tenter zone was 3 kgf / m (29.4 N / m). About the obtained film, it carried out similarly to Example 1, and evaluated optical performance. The results are shown in Table 1.

[Example 9]
(Preparation of cellulose acylate film 13)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution C. At this time, cellulose acylate having a total substitution degree of 2.85 (acetyl substitution degree 2.06 + propynyl substitution degree 0.79) was used.

[Cellulose acylate solution C composition]
Cellulose acylate 100 parts by mass Methylene chloride (first solvent) 300 parts by mass Methanol (second solvent) 54 parts by mass 1-butanol (third solvent) 11 parts by mass

(Preparation of additive solution)
A compound having the following composition was charged into another mixing tank and stirred while heating to dissolve each component to prepare an additive solution. The same compounds as in Example 6 were used as the retardation reducing compound and the wavelength dispersion adjusting agent.

[Additive solution composition]
-Retardation-reducing compound 40 parts by mass-Wavelength dispersion regulator 4 parts by mass-Methylene chloride (first solvent) 82 parts by mass-Methanol (second solvent) 15 parts by mass-1-butanol (third solvent) 3 parts by mass Parts ・ Cellulose acetate solution C 12 parts by mass

  40 parts by mass of the additive solution was added to 465 parts by mass of the cellulose acylate solution C, and a cellulose acylate film 13 having a thickness of 40 μm was produced in the same manner as in Example 4. About the obtained film, it carried out similarly to Example 1, and evaluated optical performance. The results are shown in Table 1.

[Example 10]
(Preparation of cellulose acylate film 14)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acylate solution D.

[Cellulose acylate solution D composition]
100 parts by mass of cellulose acetate having a substitution degree of 2.94
Methylene chloride (first solvent) 300 parts by mass Methanol (second solvent) 54 parts by mass 1-butanol (third solvent) 11 parts by mass

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

[Composition of matting agent solution D]
-Silica particle dispersion liquid with an average particle diameter of 16 nm 10.0 parts by mass-Methylene chloride (first solvent) 76.3 parts by mass-Methanol (second solvent) 3.4 parts by mass-1-butanol (third solvent) 0 .7 parts by mass-cellulose acylate solution D 10.3 parts by mass

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution. The compound of Example 6 was used as the compound that reduces the optical anisotropy and the wavelength dispersion adjusting agent.

(Additive solution composition)
-Retardation-reducing compound of Example 6 49.3 parts by mass-Wavelength dispersion adjusting agent of Example 6 7.6 parts by mass-Methylene chloride (first solvent) 58.4 parts by mass-Methanol (second solvent) 8. 7 parts by mass 1-butanol (third solvent) 1.8 parts by mass Cellulose acylate solution D 12.8 parts by mass

The dope was prepared by sufficiently stirring 94.6 parts by mass of the cellulose acylate solution A, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the additive solution after filtration. The dope was cast from a casting port onto a drum cooled to -10 ° C.
Peel from the drum with a residual solvent amount of 200%, and dry while gradually increasing the temperature from 45 to 110 ° C. while applying a tension of 5 kgf / m (49 N / m) in a tenter zone where both ends of the film are held by a plurality of pins. I let you. At this time, the maximum expansion / contraction ratio with respect to the tenter entrance was 98%. When the residual solvent amount was 30%, the film was removed from the pin tenter, and the edge was cut off with a cutter blade. Next, the film was dried while being transported to a drying zone composed of a plurality of roll groups with a transport tension of 10 kgf / m (98 N / m). The drying temperature was 120 ° C to 145 ° C. After cutting the both ends of the obtained film with a cutter blade to obtain a width of 1340 mm, a knurling for preventing winding deviation was provided at both ends, and a 2600 m length was wound up in a roll shape to produce a cellulose acylate film 14. As a result of examining the residual solvent amount of the obtained film, it was 0.7%. The film thickness was 80 μm.

  As shown in Table 1, the films 1 to 8, 13 and 14 as examples of the present invention have small optical anisotropy wavelength dispersion in both the film in-plane direction and the thickness direction, and the variation of the axial angle is not so great. On the other hand, the comparative films 9 to 12 satisfy some of these properties but not all of them.

[Example 11]
[Preparation of retardation film 1]
A polyimide synthesized from 2,2′-bis (3,4-discarboxyphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl is dissolved in cyclohexanone. A 15% by weight solution was prepared. This polyimide solution was applied to the cellulose acylate film 1 produced in Example 1 for 6 μm in thickness after drying, dried at 150 ° C. for 5 minutes, and then in a 150 ° C. atmosphere with a tenter stretching machine. The retardation film 1 was obtained by stretching 15% in the width direction. The film thickness of the retardation film 1 was 75 μm. About the produced film, Re value and Rth value in wavelength 590nm were measured at 25 degreeC and 60% RH using the birefringence measuring apparatus "KOBRA 21ADH" (made by Oji Scientific Instruments). For the calculation of the Rth (590) value, 1.58 was input as the average refractive index. As a result, Re (590) was 60 nm and Rth (590) was 230 nm.

[Example 12]
[Preparation of retardation film 2]
To one side of the cellulose acylate film 1 produced in Example 1, 25 ml / m ² of a 1.5 mol / L potassium isopropyl alcohol solution was applied and dried at 25 ° C. for 5 seconds. The surface of the film was dried by washing with running water for 10 seconds and blowing air at 25 ° C. In this way, only one surface of the cellulose acylate film was saponified.

On the saponification surface of the cellulose acylate film, a coating solution having the following composition was applied at 28 ml / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds. Next, the formed film was rubbed in a direction parallel to the longitudinal direction of the cellulose acylate film.

(Orientation film coating solution composition)
・ Denatured polyvinyl alcohol 10 parts by mass, water 371 parts by mass, methanol 119 parts by mass, glutaraldehyde (crosslinking agent) 0.5 part by mass

(Formation of optically anisotropic layer)
After rubbing the alignment film, 1.8 g of the following discotic (liquid crystalline) compound, 0.2 g of ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), cellulose acetate Butyrate (CAB551-0.2, Eastman Chemical Co., Ltd.) 0.04 g, Photopolymerization initiator (Irgacure 907, Ciba Geigy Co., Ltd.) 0.06 g, Sensitizer (Kayacure DETX, Nippon Kayaku Co., Ltd.) ) A coating solution prepared by dissolving 0.02 g in 8.43 g of methyl ethyl ketone was applied with a # 2.5 wire bar. Heated at 130 ° C. for 2 minutes to orient the discotic compound. Next, using a 120 W / cm high-pressure mercury lamp at 100 ° C., UV irradiation was performed for 1 minute to crosslink the discotic compound and fix the alignment state. Then, it stood to cool to room temperature, and produced the phase difference film 2.

[Example 13]
[Preparation of Polarizing Plate 1]
The retardation film 1 obtained in Example 1 was immersed in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing bath, and neutralized using 0.05 mol / L sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, the surface of the cellulose acylate film was saponified.
Next, a roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizer. One cellulose acylate film 1 subjected to alkali saponification treatment was prepared using a 3% aqueous solution of polyvinyl alcohol (Kuraray PVA-117H) as an adhesive, and bonded to a polarizer. A commercially available cellulose acetate film subjected to saponification treatment was similarly bonded to the other surface of the polarizer to produce a polarizing plate 1.

[Example 14]
[Production of Polarizing Plate 2]
An optical compensation film obtained by uniaxially stretching an Arton film (manufactured by JSR Corporation) was bonded to the surface of the polarizing plate 1 produced in Example 11 on the cellulose acylate film 1 side to produce a polarizing plate 2. The in-plane retardation Re of the optical compensation film was 270 nm, the retardation Rth in the thickness direction was 0 nm, and the Nz factor was 0.5.

[Example 15]
[Preparation of Polarizing Plate 3]
A polarizing plate 3 was produced in the same manner as in Example 14 except that a commercially available cellulose acylate film (TFY80U, manufactured by Fuji Photo Film Co., Ltd.) was used instead of the cellulose acylate film 1.

[Example 16]
(Preparation of polarizing plate 4)
250 g of Desolite KZ-7869 (UV curable hard coat composition, 72% by mass, manufactured by JSR Corporation) was dissolved in a mixed solvent of 62 g of methyl ethyl ketone and 88 g of cyclohexanone to prepare a hard coat layer coating solution. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.53.

91 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 199 g of Desolite KZ-7115, KZ-7161 (ZrO ₂ fine particle dispersion, manufactured by JSR Co., Ltd.) 52 g of methyl ethyl ketone / cyclohexanone was dissolved in a mixed solvent of 54/46% by mass. 10 g of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) was added to the obtained solution. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.61. Furthermore, 20 g of crosslinked polystyrene particles having an average particle size of 2.0 μm (SX-200H, manufactured by Soken Chemical Co., Ltd.) were added to this solution in a mixed solvent of 80 g of methyl ethyl ketone / cyclohexanone = 54/46 mass% at a high speed disperser at 5000 rpm. After adding and stirring 29 g of the dispersion that was stirred and dispersed for a period of time, it was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the antiglare layer.

The above-mentioned hard coat layer coating solution was applied to a commercially available cellulose acetate film (Fuji Photo Film Co., Ltd.) using a bar coater, dried at 120 ° C., and then air-cooled metal halide lamp of 160 W / cm (eye graphics). Was used to cure the coating layer by irradiating it with ultraviolet rays having an irradiance of 400 mW / cm ² and an irradiation energy of 300 mJ / cm ² to form a hard coat layer having a thickness of 4 μm. Further, the antiglare layer coating solution is applied using a bar coater, dried at 120 ° C. in an oxygen concentration atmosphere of 0.01% or less by nitrogen purge, and then an air-cooled metal halide lamp (eye Using a graphics), the coating layer is cured by irradiating ultraviolet rays with an irradiance of 400 mW / cm ² and an irradiation energy amount of 300 mJ / cm ² to form an anti-glare hard coat layer having a thickness of 1.4 μm. Formed.

  A polarizing plate was prepared by laminating the cellulose acylate film 1 of Production Example 1 on one side of the polarizer and the above cellulose acetate film provided with a hard coat layer and an antiglare layer on the other side. Furthermore, an adhesive sheet was pasted on the opposite side of the cellulose acylate film 1 from the polarizer, and an optical compensation film obtained by uniaxially stretching the Arton film (manufactured by JSR) used in Example 12 was pasted. Thus, a polarizing plate 4 was produced.

[Example 17]
(Production of liquid crystal display device)
A pair of polarizing plates and a pair of optical compensation sheets provided in a commercially available liquid crystal display device (manufactured by Fujitsu Limited) using a vertical alignment type liquid crystal cell were peeled off, and the liquid crystal cell was taken out.
A polarizing plate 1 was disposed on one side of the liquid crystal cell so that the cellulose acylate film 1 was on the liquid crystal cell side, and a polarizing plate 3 was disposed on the other side of the polarizing plate 1 of the liquid crystal cell to produce a liquid crystal display device. When the power of the liquid crystal display device thus manufactured was turned on and the viewing angle dependency of contrast and color at the time of black display and marginal display was visually observed, it had excellent viewing angle characteristics in all directions. .

[Example 18]
(Production of liquid crystal display device)
A pair of polarizing plates and a pair of optical compensation sheets provided in a commercially available liquid crystal display device (manufactured by Hitachi, Ltd.) using an IPS type liquid crystal cell were peeled off, and the liquid crystal cell was taken out.
A polarizing plate 2 was placed on one side of the liquid crystal cell so that the cellulose acylate film 1 was on the liquid crystal cell side, and a polarizing plate 3 was placed on the other side of the polarizing plate 2 of the liquid crystal cell to produce a liquid crystal display device. When the power of the liquid crystal display device thus manufactured was turned on and the viewing angle dependency of contrast and color at the time of black display and marginal display was visually observed, it had excellent viewing angle characteristics in all directions. .

[Example 19]
(Production of liquid crystal display device)
A polarizing plate 4 is arranged on one side of the liquid crystal cell taken out in Example 18 so that the cellulose acylate film 1 is on the liquid crystal cell side, and a polarizing plate 3 is arranged on the other side of the polarizing plate 2 of the liquid crystal cell to display a liquid crystal display. A device was made. The liquid crystal display device thus manufactured was turned on and the viewing angle dependency of contrast and color at the time of black display and marginal display was visually observed, and it had excellent viewing angle characteristics in all directions. The display quality of the front was also excellent.

[Comparative Example 5]
A polarizing plate 5 was produced in the same manner as in Example 14 except that the cellulose acylate film 9 was used instead of the cellulose acylate film 1. A liquid crystal display device was produced in the same manner as in Example 17 except that the polarizing plate 5 was used instead of the polarizing plate 4. The liquid crystal display device thus manufactured was turned on and the viewing angle dependency of the contrast and color at the time of black display and white display was visually observed. As a result, the color change in the oblique direction was large and the display quality was poor. It was.

[Comparative Example 6]
A polarizing plate 6 was produced in the same manner as in Example 14 except that the cellulose acylate film 10 was used instead of the cellulose acylate film 1. A liquid crystal display device was produced in the same manner as in Example 17 except that the polarizing plate 6 was used instead of the polarizing plate 4. When the power source of the liquid crystal display device thus manufactured was turned on and the image quality during black display was visually observed, significant light leakage occurred and the display quality was poor.

Claims (12)

Re (λ) and Rth (λ) satisfy the following formulas (I) and (II), and the in-plane slow axis direction is 0 ° ± 10 ° or 90 ° ± with respect to the film length direction. A cellulose acylate film characterized by being 10 °.
Formula (I): 0 ≦ Re (590) ≦ 10 and | Rth (590) | ≦ 25 Formula (II): | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700 ) | ≦ 35
[Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. ]   The acyl substitution degree of the cellulose acylate film is 2.80 to 3.00, and the film contains at least one compound that lowers Re (λ) and Rth (λ). 2. The cellulose acylate film as described in 1.   The film thickness of a film is 10 micrometers-120 micrometers, The cellulose acylate film in any one of Claim 1 or 2 characterized by the above-mentioned.   The cellulose acylate film according to any one of claims 1 to 3, wherein the film is a film produced with a width of 600 mm or more and a length of 100 m or more. By applying a tension of 10 to 50 kgf / m (98 to 490 N / m) in the width direction of the film in the production process of the cellulose acylate film, the in-plane slow axis direction is 0 ° with respect to the film length direction. A cellulose acylate film characterized in that ± 10 ° or 90 ° ± 10 °, and Re (λ) and Rth (λ) of the cellulose acylate film satisfy the following formulas (I) and (II): Production method.
Formula (I): 0 ≦ Re (590) ≦ 10 and | Rth (590) | ≦ 25
Formula (II): | Re (400) −Re (700) | ≦ 10 and | Rth (400) −Rth (700) | ≦ 35
[Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. ]   A method for producing a cellulose acylate film by a solution casting method, wherein the cellulose acylate film is produced by a step of transporting and drying the film while applying tension in the width direction of the film containing at least 10% or more of a solvent. The method for producing a cellulose acylate film according to claim 5.   A method for producing a cellulose acylate film by a solution casting method, holding both ends of a film, transporting the film while applying tension in the width direction of the film, and drying until the residual solvent amount is 40% or less The process according to claim 5 or 6, wherein the film is detached from the holding of both ends and then transported with a transport tension of 2 to 20 kgf / m (19.6 to 196 N / m) and dried. The manufacturing method of the cellulose acylate film of description.   The method for producing a cellulose acylate film according to any one of claims 5 to 7, wherein the film is dried at 100 to 150 ° C after releasing the holding of both ends of the film.   A retardation film, wherein at least one optically anisotropic layer is provided on the cellulose acylate film according to claim 1.   A polarizing plate, wherein at least one protective film of the polarizing plate is the cellulose acylate film according to claim 1.   A liquid crystal display device comprising at least one polarizing plate including the polarizing plate according to claim 10 and a liquid crystal cell.   The liquid crystal display device according to claim 11, wherein the liquid crystal cell is in a VA mode or an IPS mode.