JP4407304B2 - Support for optical compensation film, optical compensation film, viewing angle compensation integrated polarizing plate, and liquid crystal display device - Google Patents

Description

  The present invention relates to an optical compensation film support, an optical compensation film, a viewing angle compensation integrated polarizing plate, and a liquid crystal display device.

  At present, cellulose ester films (typically cellulose triacetate films) are widely used for silver halide photographic light-sensitive materials and optical films because of their transparency and characteristics free from optical defects. Especially as a protective film for a polarizing plate of a liquid crystal display device, it is used as an extremely preferable one.

  By the way, the display quality of the liquid crystal display device is deteriorated when observed from an oblique direction as compared with an image observed from the front. This is due to the viewing angle characteristics of the liquid crystal display device, and in order to improve this problem, a viewing angle compensation film having an appropriate phase difference correction function is disposed between the liquid crystal cell and the polarizer. Is known to be effective (see, for example, Patent Documents 1 and 2).

However, it has been found that these cannot be regarded as a complete solution.
JP 2000-154201 A JP 2002-156527 A

  The present inventors examined a solution to the above problem, and previously filed a Japanese Patent Application No. 2002-322323. The viewing angle compensation integrated polarizing plate described in the specification is provided with an appropriate retardation correction function to the polarizing plate protective film, thereby omitting the step of attaching the viewing angle compensation film to the polarizing plate, and the production process. This is a very effective technique that can achieve the simplification and thinning of the liquid crystal display device. However, in the above invention, since the film is stretched in the width (td) direction, residual strain remains in the film. This residual strain causes a dimensional change with time and causes peeling of the polarizing plate adhered to the liquid crystal cell, which has been a serious problem in practice.

  In order to solve the above problem, for example, a method of improving the adhesive force of the adhesive bonding the liquid crystal cell and the polarizing plate to suppress the physical dimensional change is conceivable. However, this technique suppresses physical dimensional changes, but the film appears to be stretched or contracted, creating a situation where the film is stressed. This stress changes the retardation of the film, and thus has a great influence on the viewing angle characteristics over time, and has been a big practical problem from the viewpoint of durability of the viewing angle characteristics.

  That is, the object of the present invention is to provide an optical compensation film having an excellent viewing angle compensation function, and to improve the durability of the viewing angle compensation function over time, an optical compensation film support, an optical compensation film, A viewing angle compensation integrated polarizing plate and a liquid crystal display device are provided.

  The object of the present invention is achieved by the following constitution.

(Claim 1)
When the photoelastic coefficients in the longitudinal and width directions of the cellulose ester film are C (md) and C (td), respectively, the respective values are in the range of 1 × 10 ⁻⁹ to 1 × 10 ⁻¹³ Pa ⁻¹ . And C (md) <C (td), and the retardation R ₀ in the cellulose ester film surface defined by the following formula (I) is in the range of 20 to 70 nm. retardation R _t the thickness direction of the cellulose ester film as defined in II) is 70～400Nm, longitudinal of the film, 80 ° C. in the width direction, before and after subjected to 50 hours at 90% RH environmental conditions When the dimensional change rates of S are S (md) and S (td), respectively, the respective values are in the range of −1 to 1%, and the relationship of | S (md) |> | S (td) | An optical compensation film characterized by satisfying Film support.

(I) R ₀ = (nx−ny) × d
(II) R _t = {(nx + ny) / 2−nz} × d
(In the formula, nx is the refractive index in the slow axis direction (width direction) in the film plane, ny is the refractive index in the fast axis direction (longitudinal direction) in the film plane, and nz is the film. The refractive index in the thickness direction of the film, and d is the thickness of the film.)
(Claim 2)
An optical compensation film using the optical compensation film support according to claim 1.

(Claim 3)
The optical compensation film according to claim 2, wherein at least one optically anisotropic layer is provided on the support for the optical compensation film according to claim 1.

(Claim 4)
The optical compensation film according to claim 2 or 3, wherein the cellulose ester used for the support for an optical compensation film according to claim 1 satisfies the following formulas (IV) and (V) simultaneously.

(IV) 2.55 ≦ X + Y ≦ 2.85
(V) 1.4 ≦ X ≦ 2.85
(However, X is a substitution degree of an acetyl group, Y is a substitution degree of a propionyl group and / or a butyryl group.)
(Claim 5)
The acetylation degree of the cellulose ester film used for the optical compensation film support according to claim 1 is in the range of 59.0 to 61.5%, and at least two aromatic rings are contained with respect to 100 parts by mass of the cellulose ester. The optical compensation film according to any one of claims 2 to 4, comprising 0.1 to 20 parts by mass of a compound having two.

(Claim 6)
The optical compensation film according to any one of claims 2 to 4, further comprising an optically anisotropic layer formed by fixing a nematic hybrid alignment structure.

(Claim 7)
The optical compensation film according to any one of claims 2 to 4, further comprising an optically anisotropic layer containing a discotic liquid crystalline compound.

(Claim 8)
A viewing angle compensation-integrated polarizing plate comprising two protective films and a polarizer, wherein at least one of the protective films is the optical compensation film according to any one of claims 2 to 7, and the optical compensation film A viewing angle compensation-integrated polarizing plate, wherein the slow axis of the cellulose ester film of the support for an optical compensation film and the transmission axis of the polarizer are substantially parallel.

(Claim 9)
A liquid crystal display device using the viewing angle compensation integrated polarizing plate according to claim 8.

  According to the present invention, an optical compensation film having an excellent viewing angle compensation function is provided, and the durability of the viewing angle compensation function over time can be improved. Support for optical compensation film, optical compensation film, viewing angle compensation A body-type polarizing plate and a liquid crystal display device can be provided.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

As described above, the liquid crystal display device generally has viewing angle characteristics, and there is a problem that the contrast is lowered when the liquid crystal display device is observed from a position having an angle from the normal direction of the liquid crystal cell. In order to solve this problem, it is known that it is effective to dispose a retardation film (optical compensation film) having an appropriate retardation between the liquid crystal cell and the polarizer. In general, it is preferable that the in-plane retardation (R _o ) is in the range of 20 to 70 nm and the depth retardation (R _t ) is in the range of 70 to 400 nm.

  In order to control the retardation of the cellulose ester film, the degree of substitution of the cellulose ester to be used and the type of substituent are important factors. In the present invention, when the degree of acetyl substitution of the cellulose ester is X and the degree of substitution of the propionyl group and / or butyryl group is Y, 2.55 ≦ X + Y ≦ 2.85 and 1.4 ≦ X ≦ 2.85 Further, by stretching the film, it was possible to obtain a retardation suitable as an optical compensation polarizing plate (viewing angle compensation integrated polarizing plate).

  Moreover, in this invention, the acetylation degree of a cellulose-ester film is the range of 59.0-61.5%, and the compound which has at least two aromatic rings is 0.1 with respect to 100 mass parts of cellulose-ester films. By stretching a cellulose ester film containing ˜20 parts by mass, a retardation suitable as a viewing angle compensation cellulose ester film could be obtained.

  Further, in order to improve the viewing angle characteristics of the liquid crystal display panel, it is known that it is effective to provide a layer containing a rod-like or discotic liquid crystalline compound on an optically compensated cellulose ester film having a suitable retardation. ing. That is, as the optically anisotropic layer, viewing angle characteristics can be further improved by providing a layer of rod-like liquid crystal molecules to form a nematic hybrid structure or a layer of discotic liquid crystal molecules.

  In order to improve the viewing angle characteristics of the liquid crystal display device, light leakage in the case of black display that the slow axis of the optically compensated cellulose ester film and the transmission axis of the polarizer are substantially parallel or orthogonal is suppressed. Important from the point of view. Further, as described above, viewing angle characteristics can be improved by coating an optically anisotropic layer with a liquid crystalline compound on a cellulose ester film. In this case, it is very preferable that the slow axis of the cellulose ester film as the support is orthogonal to the slow axis of the optically anisotropic layer.

  In consideration of mass production of liquid crystal display industrially, cellulose is used to form an optically anisotropic layer containing an optically anisotropic compound by coating a liquid crystalline compound and aligning the liquid crystalline compound. Although it is necessary to rub the ester film in a roll state, rubbing in the width direction is very difficult, and it is much easier to rub in the longitudinal direction (traveling direction). On the other hand, in order to make the slow axis of a cellulose ester film orthogonal to this, it is desirable to stretch in the width direction. Since the longitudinal direction is good for making a polarizer by stretching, the absorption axis of the polarizer is the longitudinal direction and the transmission axis is the lateral direction. As a result, the slow axis of the viewing angle compensation cellulose ester film and the transmission axis of the polarizer Are substantially parallel.

  It is also known that the viewing angle can be further improved by introducing a nematic polymer liquid crystalline compound as an optically anisotropic layer with a hybrid alignment structure in which the pretilt angle of liquid crystal molecules changes in the depth direction. ing.

  The change in viewing angle characteristics with time is due to the change in retardation with time. As a result of intensive studies, the inventors have arrived at the present invention paying attention to the anisotropy of the photoelastic coefficient and the anisotropy of the dimensional change. The photoelastic coefficient represents the response of retardation change to stress, and the dimensional change is considered to be a value related to the magnitude of stress applied to the film over time. For example, when a cellulose ester film is stretched in the width (td) direction, the absolute value of dimensional change over time in the width direction is larger than that in the longitudinal (md) direction, and further, the photoelastic coefficient in the width direction. Becomes larger. The retardation change is considered to increase as the photoelastic coefficient is large and the absolute value of the dimensional change is large, and the change in the td direction is greatly changed by the two synergistic effects compared to the md direction. As a result, the viewing angle change with time increases, resulting in a film with poor durability. In the present invention, after stretching, for example, by applying appropriate heat, the strain remaining in the stretching direction is relaxed, thereby reducing the absolute value of the dimensional change in the direction where the photoelastic coefficient is large, thereby reducing the viewing angle. Improved the durability of the compensation function.

  Further, the term “substantially parallel” in the present invention means that it may deviate from parallel within a range that does not cause much problem, and the angle formed by the axis of the object is within about ± 10 °, preferably ± Within 3 °, more preferably within ± 1 °. On the other hand, “substantially orthogonal” means that it may have a constant width from 90 °, and the width is specifically about 80 ° to 100 °, but is in the range of 85 ° to 95 °. Is better and is most preferably 90 °.

  Hereinafter, the constituent requirements of the present invention, the method for producing the optical compensation film, and the like will be described in detail.

[Film formation of cellulose ester film]
First, a method for forming a cellulose ester film according to the present invention will be described (a solution casting film forming method is shown as a representative example).

(1) Dissolution process:
In the dissolution vessel, the dope is formed by dissolving the cellulose ester in an organic solvent mainly composed of a good solvent for the cellulose ester while stirring. There are various dissolution methods, such as performing at normal pressure at a temperature below the boiling point of the main solvent, performing pressurization at a temperature higher than the boiling point of the main solvent, cooling to below zero degree, or performing at high pressure. Any of these is a preferable dissolution method, but a high-temperature dissolution method in which the solution is dissolved in a pressurized state above the boiling point of the main solvent is more preferably used. After dissolution, the dope is filtered with a filter medium, defoamed, and sent to the next process with a pump.

  In the dope, additives having various functions such as a plasticizer, an antioxidant, an ultraviolet absorber, a matting agent, and a retardation increasing agent can be added. These additives may be added together with the cellulose ester and the solvent during the preparation of the dope, or may be added during or after the dope preparation. Further, a thermal stabilizer such as an alkaline earth metal salt, an antistatic agent, a flame retardant, a slip agent, and an oil agent may be added.

  (2) Casting process: An endless metal belt or a rotating metal drum (hereinafter referred to as an infinite transport) in which the dope is fed to a pressurizing die through a pressurization type quantitative gear pump and the surface is a mirror surface at the casting position. This is a step of casting a dope from a pressure die onto a metal support. The die casting apparatus is preferably a pressure die that can adjust the slit shape of the die part and easily make the film thickness of the web uniform. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked.

(3) Solvent evaporation step:
In this step, the organic solvent is evaporated by heating the web on a metal support. In order to evaporate the organic solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back surface of the metal support by a liquid, a method of transferring heat from the front and back by radiant heat, etc. Preferably used.

(4) Peeling process:
This is a step of peeling the web from which the organic solvent has evaporated on the metal support from the metal support. The peeled web is sent to the next drying step. If the residual solvent amount (described later) of the web at the time of peeling is too large, peeling will be difficult, or conversely, if it is peeled off after sufficiently drying on the metal support, part of the web will be peeled off.

  As a method for increasing the film-forming speed, there is gel casting that can remove most of the residual solvent. For example, a poor solvent for the cellulose ester is added to the dope, and the dope is cast and then gelled, and the temperature of the metal support is lowered to gel. When gelled on a metal support, the film strength is high, and even if the amount of residual solvent is large, it can be peeled off. As a result, peeling can be accelerated and the film forming speed can be increased. When peeling at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be impaired, or slippage and vertical stripes due to peeling tension will tend to occur, and the amount of residual solvent in peeling will increase due to the balance between economic speed and quality. Can be decided. In this invention, it is preferable to peel at 10-120 mass%.

(5) Drying process:
This is a step of drying the web using a drying device that alternately conveys the web through guide rolls arranged in a staggered manner and / or a tenter drying device that clips and conveys both ends of the web with clips. As a drying means, hot air is generally blown on both sides of the web, but there is also a means for heating by applying a microwave instead of the wind. Too much drying tends to impair the flatness of the finished film. The drying temperature throughout is preferably 40 to 250 ° C, more preferably 70 to 180 ° C. The drying temperature, the amount of drying air, and the drying time differ depending on the organic solvent used, and the drying conditions may be appropriately selected according to the type and combination of the solvents used.

  In the drying process after peeling from the metal support surface, the web tends to shrink in both directions due to evaporation of the solvent. Shrinkage increases as the temperature rapidly dries. Drying while suppressing this shrinkage as much as possible is preferable for improving the flatness of the finished film. From this viewpoint, for example, as shown in Japanese Patent Application Laid-Open No. 62-46625, in the entire drying process or a part of the process, the web is clipped in the width direction and dried while maintaining the width at both ends of the web. (Tenter method) is preferred. At this time, the retardation can be controlled by controlling the stretch ratio of the web, the amount of residual solvent, and the temperature.

  In the present invention, for example, the amount of residual solvent in the film is 5 to 30% by mass, the temperature during film stretching is 60 to 160 ° C., and the film is stretched in the width direction by a tenter in the range of a stretching ratio of 1.0 to 2.0 times. By doing so, the retardation suitable for viewing angle compensation was able to be provided. At this time, the width direction (td direction) of the film was the nx direction, the longitudinal direction was the ny direction, and the thickness direction was the nz direction. Furthermore, at the same time, anisotropy is given to the photoelastic coefficient, and when the photoelastic coefficients in the longitudinal direction and the lateral direction are C (md) and C (td), respectively, the characteristic is C (md) <C (td). I was able to control it.

  At this point, the film is in a state in which more strain remains in the td direction than in the md direction, and the dimensional change rate before and after the film is processed for 50 hours at 80 ° C. and 90% RH in the longitudinal and width directions. Where S (md) and S (td) are the characteristics of | S (md) | <| S (td) |. Therefore, in the present invention, after width stretching with a tenter is completed, drying is performed while relaxing residual strain in the td direction while carrying a roll in an atmosphere of 40 to 120 ° C. in a tension range of 50 to 200 N. An optical compensation film satisfying S (md) |> | S (td) | could be produced. At this time, relaxation in the td direction is an important condition. For example, by repeating the conveyance with 400 or more rolls in the range of the temperature and tension conditions, the characteristics in the dimensional change rate, which is a requirement of the present invention. The condition was achieved.

In particular, in the dimensional change rate S (td) (%) in the same direction as the photoelastic coefficient C (td) (Pa ⁻¹ ) in the td direction, C (td) × | S (td) | <5.0 × ^Satisfying the relationship of 10 ⁻¹⁴ is preferable in terms of durability of the viewing angle function.

  The dimensional change rate S (td) in the same direction as the photoelastic coefficient C (td) in the td direction, and the dimensional change rate S (md) in the same direction as the photoelastic coefficient C (md) in the md direction. , C (td) × | S (td) | <C (md) × | S (md) | is preferable in terms of durability of the viewing angle compensation function.

(6) Winding process:
This is a step of winding the web after drying as a film. By setting the amount of residual solvent to finish drying to 2% by mass or less, preferably 0.4% by mass or less, a film having good dimensional stability can be obtained. The winding method may be a commonly used winder, and there are methods for controlling the tension such as the constant torque method, constant tension method, taper tension method, and program tension control method with constant internal stress. That's fine.

  The amount of residual solvent can be expressed by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is the mass of the web at an arbitrary point, and N is the mass when M is dried at 110 ° C. for 3 hours.

  The film thickness of the cellulose ester film varies depending on the purpose of use, but is in the range of 10 to 200 μm. From the viewpoint of thinning the liquid crystal display device, the finished film is preferably in the range of 10 to 75 μm, and more preferably in the range of 10 to 60 μm. The range of 10 to 40 μm is particularly preferable. If it is too thin, for example, the required strength as a protective film for a polarizing plate may not be obtained. If it is too thick, the advantage of thinning the conventional cellulose ester film is lost. In order to adjust the film thickness, it is preferable to control the dope concentration, the pumped liquid amount, the slit gap of the die base, the extrusion pressure of the die, the speed of the metal support, etc. so as to obtain a desired thickness. Further, as a means for making the film thickness uniform, it is preferable to use a film thickness detection means to feed back and adjust the programmed feedback information to each of the above devices.

  In the process from immediately after casting through the solution casting film forming method to drying, the atmosphere in the drying apparatus may be air, or may be performed in an inert gas atmosphere such as nitrogen gas or carbon dioxide gas. . However, it is a matter of course that the danger of the explosion limit of the evaporating solvent in the dry atmosphere must always be considered.

[Cellulose ester film and its composition]
The cellulose as a raw material for the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively.

  The number average molecular weight of the cellulose ester used in the present invention is preferably in the range of 60000-300000, more preferably in the range of 80000-200000. Within that range, the film has strong mechanical strength and can be used with peace of mind.

  The number average molecular weight of the cellulose ester is measured by high performance liquid chromatography under the following conditions as follows.

Solvent: Acetone Column: MPW × 1 (manufactured by Tosoh Corporation)
Sample concentration: 0.2 mass / volume%
Flow rate: 1.0 ml / min Sample injection volume: 300 μl
Standard sample: polymethyl methacrylate (Mw = 188200)
Temperature: 23 ° C.

The cellulose ester used in the present invention is obtained by acylating a cellulose raw material. When the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), an organic acid such as acetic acid or an organic solvent such as methylene chloride is used, and a protic catalyst such as sulfuric acid is used as a catalyst. To react. When the acylating agent is an acid chloride (eg, CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl), the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, it can be synthesized by the method described in JP-A-10-45804.

  In the cellulose ester, the acyl group reacts with the hydroxyl group of the cellulose molecule. Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution.

  The cellulose ester used in the present invention is a cellulose ester to which a propionyl group or a butyryl group is bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate. The butyryl group includes iso- in addition to n-. Cellulose acetate propionate having a large substitution degree of propionyl group is excellent in water resistance and is useful as a film for a liquid crystal display device.

  The measuring method of the substitution degree of an acyl group can be measured according to ASTM-D817-96.

  In order to control the retardation and photoelastic coefficient of the cellulose ester film, the degree of substitution of the cellulose ester used and the type of substituent are important factors. In the present invention, when the acetyl substitution degree of the cellulose ester is X and the substitution degree of the propionyl group and / or butyryl group is Y, 2.3 ≦ X + Y ≦ 2.85 and 1.4 ≦ X ≦ 2.85 It is easy to obtain a suitable retardation as a viewing angle compensation polarizing plate (viewing angle compensation integrated polarizing plate).

  Moreover, in this invention, the acetylation degree of a cellulose-ester film is the range of 59.0-61.5%, and 0.01-0.0 with respect to 100 mass parts of cellulose-ester films the compound which has at least two aromatic rings. By including 20 parts by mass, it is easy to obtain a film having a retardation and a photoelastic coefficient suitable as a viewing angle compensation cellulose ester film.

[Additive for cellulose ester film (support)]
In order to prepare a cellulose ester film containing a compound having at least two aromatic rings according to the present invention and having at least two aromatic rings having a planar structure, the compound and the cellulose ester film are doped together with an organic solvent. It is made to contain and it forms into a film by the solution casting film forming method.

  A compound having at least two aromatic rings according to the present invention and having at least two aromatic rings having a planar structure may have a structure in which two aromatic rings are close to the same plane. That is, it has at least 5 or more and up to 10 π electrons of π electrons of two aromatic rings, π electrons of aromatic heterocycles, or aromatic rings including a linking group connecting them. It is preferable.

  Moreover, it is preferable that the number of the aromatic rings which this compound has is 2-20, More preferably, it is 2-12, More preferably, it is 2-8. The aromatic ring includes an aromatic hydrocarbon ring and an aromatic heterocycle. The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable.

  Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring. As the aromatic ring, benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferable.

  The bond relationship of at least two aromatic rings is (a) when a condensed ring is formed, (b) when directly linked by a single bond, (c) when linked via a linking group, and (d) having π electrons It can be classified into the case of bonding through a linking group (a spiro bond cannot be formed because of an aromatic ring). However, in the case of (b) or (c), it is necessary that the two aromatic rings have a planar structure.

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

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

  The linking group of (c) or (d) or the linking group having π electrons is also preferably bonded to carbon atoms of two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof. Examples of linking groups composed of combinations are shown below. In addition, the relationship between the left and right in the following examples of linking groups may be reversed. For example, -CO-O-, -CO-NH-, -alkylene-O-, -NH-CO-NH-, -NH-CO-O-, -O-CO-O-, -O-alkylene-O -, -CO-alkenylene-, -CO-alkenylene-NH-, -CO-alkenylene-O-, -alkylene-CO-O-alkylene-O-CO-alkylene-, -O-alkylene-CO-O-alkylene. -O-CO-alkylene-O-, -O-CO-alkylene-CO-O-, -NH-CO-alkenylene-, -O-CO-alkenylene-, etc. As the group directly linked to the aromatic heterocycle, —CO— or alkenylene is preferable.

  The aromatic ring and the linking group may have a substituent. However, the substituent must have a structure that does not cause steric hindrance of the two aromatic rings, that is, a planar structure. In steric hindrance, the type and position of substituents are problematic. As the type of substituent, a sterically bulky substituent (for example, a tertiary alkyl group) is likely to cause steric hindrance, and the position of the substituent is a position adjacent to the bond of the aromatic ring (the benzene ring). If the ortho position is substituted, steric hindrance is likely to occur and should be avoided.

  Examples of the substituent include halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, cyano, amino, nitro, sulfo, carbamoyl, sulfamoyl, ureido, alkyl group, alkenyl group, alkynyl group, aliphatic acyl group , Aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamido group, aliphatic substituted amino group, aliphatic substituted carbamoyl group, aliphatic Substituted sulfamoyl groups, aliphatic substituted ureido groups and non-aromatic heterocyclic groups are included.

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

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

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

  The molecular weight of these compounds is preferably 300 to 800. The boiling point is preferably 260 ° C. or higher. The boiling point can be measured using a commercially available measuring device (for example, TG / DTA100, manufactured by Seiko Electronics Industry Co., Ltd.). Specific examples are shown below, but are not limited thereto.

  Further, the compound having at least two aromatic rings according to the present invention and having at least two aromatic rings having a planar structure is a compound having a triphenylene ring represented by the following general formula (1) in addition to the above. Are also preferably used.

In general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, a halogen atom, nitro, sulfo, an aliphatic group, an aromatic group or a heterocyclic ring. Group, —O—R ₁₁ , —S—R ₁₂ , —CO—R ₁₃ , —O—CO—R ₁₄ , —CO—O—R ₁₅ , —O—CO—O—R ₁₆ , —NR ₁₇ R _{18, -CO-NR 19 R 20} , -NR 21 -CO-R 22, -O-CO-NR 23 R 24, -SiR 25 R 26 R 27, -O-SiR 28 R 29 R 30, -S- CO—R ₃₁ , —O—SO ₂ —R ₃₂ , —SO—R ₃₃ , —NR ₃₄ —CO—O—R ₃₅ , —SO ₂ —R ₃₆ or —NR ₃₇ —CO—NR ₃₈ R ₃₉ R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , R ₁₉ , R ₂₀ , R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , R ₂₆ , _{R 27, R 28, R 29} , R 30, R 31, R 32, R 33, _{34, R 35, R 36,} R 37, R 38 and R ₃₉ each independently represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group; and, R ₁ and R _2, R ₃ R ₄ or R ₅ and R ₆ may combine with each other to form a ring.

R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are —O—R ₁₁ , —S—R ₁₂ , —O—CO—R ₁₄ , —O—CO—O—R ₁₆ , — NR ₁₇ R ₁₈ , —NR ₂₁ —CO—R ₂₂ or —O—CO—NR ₂₃ R ₂₄ is preferred, —O—R ₁₁ , —S—R ₁₂ , —O—CO—R ₁₄ , — more preferably O-CO-O-R ₁₆ or _{-O-CO-NR 23 R 24} , more preferably from -O-R ₁₁ or _{-O-CO-R 14, -O} -CO- and most preferably R _14.

_{R 11, R 12, R 13} , R 14, R 15, R 16, R 17, R 18, R 19, R 20, R 21, R 22, R 23, R 24, R 25, R 26, R 27 , R ₂₈ , R ₂₉ , R ₃₀ , R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , R ₃₈ and R ₃₉ are a hydrogen atom, an aliphatic group or an aromatic group. It is preferable. R ₁₄ of -O-CO-R ₁₄ is most preferably an aromatic group. In the general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are preferably the same group.

  In the present invention, the aliphatic group means an alkyl group, an alkenyl group, an alkynyl group, a substituted alkyl group, a substituted alkenyl group and a substituted alkynyl group. The alkyl group may be cyclic (cycloalkyl group). Moreover, the alkyl group may have a branch. The number of carbon atoms in the alkyl group is preferably 1-30, more preferably 1-20, and most preferably 1-10. Examples of alkyl groups include methyl, ethyl, i-propyl, butyl, i-butyl, s-butyl, t-butyl, t-pentyl, hexyl, octyl, t-octyl, dodecyl and tetracosyl. The alkenyl group may be cyclic (cycloalkenyl group). The alkenyl group may have a branch. The alkenyl group may have two or more double bonds.

  The alkenyl group has preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and most preferably 2 to 10 carbon atoms. Examples of the alkenyl group include vinyl, allyl and 3-heptenyl. The alkynyl group may be cyclic (cycloalkynyl group). Moreover, the alkynyl group may have a branch. The alkynyl group may have two or more triple bonds. The number of carbon atoms in the alkynyl group is preferably 2 to 30, more preferably 2 to 20, and most preferably 2 to 10. Examples of the alkynyl group include ethynyl, 2-propynyl, 1-pentynyl and 2,4-octadiynyl.

Examples of the substituent of the substituted alkyl group, the substituted alkenyl group and the substituted alkynyl group include a halogen atom, nitro, sulfo, an aromatic group, a heterocyclic group, —O—R ₄₁ , —S—R ₄₂ , —CO—R. ₄₃ , —O—CO—R ₄₄ , —CO—O—R ₄₅ , —O—CO—O—R ₄₆ , —NR ₄₇ R ₄₈ , —CO—NR ₄₉ R ₅₀ , —NR ₅₁ —CO—R _{52 , -O-CO-NR 53 R} 54, include -SiR ₅₅ R ₅₆ R ₅₇ R ₅₈ and _{-O-SiR 59 R 60 R 61} R 62. _{R 41, R 42, R 43} , R 44, R 45, R 46, R 47, R 48, R 49, R 50, R 51, R 52, R 53, R 54, R 55, R 56, R 57 , R ₅₈ , R ₅₉ , R ₆₀ , R ₆₁ and R ₆₂ are each independently a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group.

  The alkyl part of the substituted alkyl group is the same as the above alkyl group. Examples of substituted alkyl groups include benzyl, phenethyl, 2-methoxyethyl, ethoxymethyl, 2- (2-methoxyethoxy) ethyl, 2-hydroxyethyl, hydroxymethyl, 2-carboxyethyl, carboxymethyl, ethoxycarbonylmethyl, 4-acryloyloxybutyl, trichloromethyl and perfluoropentyl are included. The alkenyl part of the substituted alkenyl group is the same as the above alkenyl group. Examples of substituted alkenyl groups include styryl and 4-methoxystyryl. The alkynyl part of the substituted alkynyl group is the same as the above alkynyl group. Examples of substituted alkynyl groups include 4-butoxyphenylethynyl, 4-propylphenylethynyl and trimethylsilylethynyl.

In the present invention, the aromatic group means an aryl group and a substituted aryl group. The number of carbon atoms in the aryl group is preferably 6-30, more preferably 6-20, and most preferably 6-10. Examples of the aryl group include phenyl, 1-naphthyl and 2-naphthyl. Examples of the substituent of the substituted aryl group include a halogen atom, a nitro group, a sulfonic acid group, an aliphatic group, an aromatic group, a heterocyclic group, —O—R ₇₁ , —S—R ₇₂ , —CO—R _73. , -O-CO-R ₇₄ , -CO-O-R ₇₅ , -O-CO-O-R ₇₆ , -NR ₇₇ R ₇₈ , -CO-NR ₇₉ R ₈₀ , -NR ₈₁ -CO-R ₈₂ , _{-O-CO-NR 83 R 84} , include -SiR ₈₅ R ₈₆ R ₈₇ R ₈₈ and _{-O-SiR 89 R 90 R 91} R 92.

_R71 , _R72 , _R73 , _R74 , _R75 , _R76 , _R77 , _R78 , _R79 , _R80 , _R81 , _R82 , _R83 , _R84 , _R85 , _R86 , _R87 , R ₈₈ , R ₈₉ , R ₉₀ , R ₉₁ and R ₉₂ are each independently a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group.

  The aryl part of the substituted aryl group is the same as the above aryl group. Examples of substituted aryl groups include p-biphenylyl, 4-phenylethynylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 3-ethoxyphenyl, 4-ethoxyphenyl, 2- Propoxyphenyl, 3-propoxyphenyl, 4-propoxyphenyl, 2-butoxyphenyl, 3-butoxyphenyl, 4-butoxyphenyl, 2-hexyloxyphenyl, 3-hexyloxyphenyl, 4-hexyloxyphenyl, 2-octyloxy Phenyl, 3-octyloxyphenyl, 4-octyloxyphenyl, 2-dodecyloxyphenyl, 3-dodecyloxyphenyl, 4-dodecyloxyphenyl, 2-tetracosyloxyphenyl, 3-tetracosyloxyphenyl, 4- Tet Cosyloxyphenyl, 3,4-dimethoxyphenyl, 3,4-diethoxyphenyl, 3,4-dihexyloxyphenyl, 2,4-dimethoxyphenyl, 2,4-diethoxyphenyl, 2,4-dihexyloxyphenyl 3,5-dimethoxyphenyl, 3,5-dimethoxyphenyl, 3,5-dihexyloxyphenyl, 3,4,5-trimethoxyphenyl, 3,4,5-triethoxyphenyl, 3,4,5-tri Hexyloxyphenyl, 2,4,6-trimethoxyphenyl, 2,4,6-triethoxyphenyl, 2,4,6-trihexyloxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 2-bromophenyl, 3-bromo Enyl, 4-bromophenyl, 3,4-difluorophenyl, 3,4-dichlorophenyl, 3,4-dibromophenyl, 2,4-difluorophenyl, 2,4-dichlorophenyl, 2,4-dibromophenyl, 3,5 -Difluorophenyl, 3,5-dichlorophenyl, 3,5-dibromophenyl, 3,4,5-trifluorophenyl, 3,4,5-trichlorophenyl, 3,4,5-tribromophenyl, 2,4, 6-trifluorophenyl, 2,4,6-trichlorophenyl, 2,4,6-tribromophenyl, pentafluorophenyl, pentachlorophenyl, pentabromophenyl, 2-iodophenyl, 3-iodophenyl, 4-iodophenyl 2-formylphenyl, 3-formylphenyl, 4-formylphenyl, 2-ben Zoylphenyl, 3-benzoylphenyl, 4-benzoylphenyl, 2-carboxyphenyl, 3-carboxyphenyl, 4-carboxyphenyl, o-tolyl, m-tolyl, p-tolyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2- (2-methoxyethoxy) phenyl, 3- (2-methoxyethoxy) phenyl, 4- (2-methoxyethoxy) phenyl, 2-ethoxycarbonylphenyl, 3-ethoxycarbonylphenyl, 4-ethoxy Carbonylphenyl, 2-benzoyloxyphenyl, 3-benzoyloxyphenyl and 4-benzoyloxyphenyl are included.

  In the present invention, the heterocyclic group may have a substituent. The heterocyclic ring of the heterocyclic group is preferably a 5-membered ring or a 6-membered ring. The heterocyclic ring of the heterocyclic group may be condensed with an aliphatic ring, an aromatic ring or another heterocyclic ring. Examples of heteroatoms in the heterocycle include B, N, O, S, Se and Te. Examples of the heterocyclic group include a pyrrolidine ring, a morpholine ring, a 2-bora-1,3-dioxolane ring, and a 1,3-thiazolidine ring. Examples of the unsaturated heterocyclic ring include imidazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzotriazole ring, benzoselenazole ring, pyridine ring, pyrimidine ring and quinoline ring. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the substituted aryl group.

The molecular weight of the compound having a triphenylene ring is preferably 300 to 2,000. The boiling point of the compound is preferably 260 ° C. or higher. The boiling point can be measured using a commercially available measuring device (for example, TG / DTA100, manufactured by Seiko Electronics Industry Co., Ltd.). Specific examples of R corresponding to the following general formula (2) of the compound in which 6 substituents of R _{1 to} R _{6 in} the general formula (1) have the same triphenylene ring are shown below.

  As R, (B-1) fluoro, (B-2) chloro, (B-3) bromo, (B-4) formyl, (B-5) benzoyl, (B-6) carboxyl, (B-7) ) Butylamino, (B-8) dibenzylamino, (B-9) trimethylsilyloxy, (B-10) 1-pentynyl, (B-11) ethoxycarbonyl, (B-12) 2-hydroxyethoxycarbonyl, B-13) Phenoxycarbonyl, (B-14) N-phenylcarbamoyl, (B-15) N, N-diethylcarbamoyl, (B-16) 4-methoxybenzoyloxy, (B-17) N-phenylcarbamoyloxy (B-18) hexyloxy, (B-19) 4-hexyloxybenzoyloxy, (B-20) ethoxy, (B-21) benzoyloxy, (B-22) -Dodecyloxyphenylthio, (B-23) t-octylthio, (B-24) p-fluorobenzoylthio, (B-25) isobutyrylthio, (B-26) p-methylbenzenesulfinyl, (B-27) ethane Sulfinyl, (B-28) benzenesulfonyl, (B-29) methanesulfonyl, (B-30) 2-methoxyethoxy, (B-31) propoxy, (B-32) 2-hydroxyethoxy, (B-33) 2-carboxyethoxy, (B-34) 3-heptenyloxy, (B-35) 2-phenylethoxy, (B-36) trichloromethoxy (B-37) 2-propynyloxy, (B-38) 2,4- Octadiynyloxy, (B-39) perfluoropentyloxy, (B-40) ethoxycarbonylmethoxy, (B-41) -Methoxyphenoxy, (B-42) m-ethoxyphenoxy, (B-43) o-chlorophenoxy, (B-44) m-dodecyloxyphenoxy, (B-45) 4-pyridyloxy, (B-46) Pentafluorobenzoyloxy, (B-47) p-hexyloxybenzoyloxy, (B-48) 1-naphthoyloxy, (B-49) 2-naphthoyloxy, (B-50) 5-imidazolecarbonyloxy, (B-51) o-phenoxycarbonylbenzoyloxy, (B-52) m- (2-methoxyethoxy) benzoyloxy, (B-53) o-carboxybenzoyloxy, (B-54) p-formylbenzoyloxy, (B-55) m-ethoxycarbonylbenzoyloxy, (B-56) p-pivaloylbenzoyloxy, (B-57) propionyloxy, (B-58) phenylacetoxy, (B-59) cinnamoyloxy, (B-60) hydroxyacetoxy, (B-61) ethoxycarbonylacetoxy, (B-62) m-butoxy Phenylpropioroyloxy, (B-63) propioroyloxy, (B-64) trimethylsilylpropioroyloxy, (B-65) 4-octenoyloxy, (B-66) 3-hydroxypropionyloxy, (B -67) 2-methoxyethoxyacetoxy, (B-68) perfluorobutyryloxy, (B-69) methanesulfonyloxy, (B-70) p-toluenesulfonyloxy, (B-71) triethylsilyl, (B -72) m-butoxyphenoxycarbonylamino, (B-73) hexyl, (B-7) ) Phenyl, (B-75) 4-pyridyl, (B-76) benzyloxycarbonyloxy, (B-77) m-chlorobenzamide, may be mentioned (B-78) 4-methylanilino like.

Specific examples of R corresponding to the following general formula (3) of the compound having 5 R and 6 identical R triphenylene rings among the R _{1 to} R ₆ substituents of the above general formula (1) It is shown below.

  R includes (B-79) nitro, (B-80) sulfo, (B-81) formyl, (B-82) carboxyl, (B-83) methoxycarbonyl, (B-84) benzyloxycarbonyl, B-85) Phenoxycarbonyl can be mentioned.

Specific examples of R corresponding to the following general formula (4) of compounds having the same R triphenylene ring in which R _{1 in the} general formula (1) is a hydroxyl group and five substituents R _{2 to} R ₆ are as follows: Show.

  Examples of R include (B-86) butoxy, (B-87) hexyloxy, (B-88) dodecyloxy, (B-89) hexanoyloxy, and (B-90) carboxymethoxy.

As a further example of R ₁ to R ₅ in the general formula (1), is the following B-91~B-100.

  The addition amount of the compound having at least two aromatic rings and a compound having a compound in which at least two aromatic rings have a planar structure is 0 in the dope of the cellulose ester from the viewpoint of preventing bleed out. It is preferable to mix 4 to 10% by mass, and a range of 1.5 to 10% by mass is more preferable. Moreover, as a quantity to contain in a cellulose-ester film, 0.01-20 mass% is preferable with respect to 100 mass parts of cellulose sels, 5-30 mass% is further preferable, and 8-30 mass% is especially preferable.

  It is preferable that the cellulose ester film contains a deterioration inhibitor such as an antioxidant or a radical scavenger for preventing the cellulose ester film used in the liquid crystal display device according to the present invention from deteriorating.

  As the degradation inhibitor, hindered phenol compounds are preferably used, and 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl). -4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3 5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- ( , 5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5 -Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate Etc. In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-t A phosphorus-based processing stabilizer such as -butylphenyl) phosphite may be used in combination. The amount of these compounds added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the cellulose ester.

  Further, in order to prevent the cellulose ester film according to the present invention from being deteriorated by ultraviolet rays, it is preferable to contain an ultraviolet absorber that cuts or weakens ultraviolet rays poured into the liquid crystal display device in addition to the above-described deterioration preventing agent. As the ultraviolet absorber, those which are excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and have little absorption of visible light having a wavelength of 400 nm or more are preferable from the viewpoint of liquid crystal display properties. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole compounds and benzophenone compounds. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to the cellulose ester is small. For example, Tinuvin 109, Tinuvin 171, Tinuvin 326, Tinuvin 327, Tinuvin 328, etc. manufactured by Ciba Specialty Chemicals can be preferably used. Depending on the amount used, a low molecular weight UV absorber may be formed in the same manner as a plasticizer. Therefore, the added amount is 0.01 to 5% by mass, preferably 0.13 to 3% by mass with respect to the cellulose ester. Some of these ultraviolet absorbers have at least two aromatic rings useful in the present invention, and at least two aromatic rings overlap with a compound having a planar structure.

  In the present invention, the cellulose ester film preferably contains fine particles. Examples of the fine particles include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, and hydration. It is preferable to contain inorganic fine particles such as calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and crosslinked polymer fine particles. Of these, silicon dioxide is preferable because it can reduce the haze of the film. The average particle size of the secondary particles of the fine particles is in the range of 0.01 to 1.0 μm, and the content is preferably 0.005 to 0.3% by mass with respect to the cellulose ester. In many cases, fine particles such as silicon dioxide are surface-treated with an organic material, but such a material is preferable because it can reduce the haze of the film. Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes (especially alkoxysilanes having a methyl group), silazane, siloxane and the like. The larger the average particle size of the fine particles, the greater the mat effect, and on the contrary, the smaller the average particle size, the better the transparency. Therefore, the average particle size of the preferred primary particles is 5 to 50 nm, more preferably 7 to 16 nm. It is. These fine particles are usually present as aggregates in the cellulose ester film, and it is preferable to form irregularities of 0.01 to 1.0 μm on the surface of the cellulose ester film. Examples of the fine particles of silicon dioxide include Aerosil (Aerosil) 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, etc. manufactured by Aerosil Co., preferably AEROSIL (Aerosil) 200V, R972, R972V, R974, R202, and R812. Two or more kinds of these fine particles may be used in combination. When using 2 or more types together, it can mix and use in arbitrary ratios. In this case, fine particles having different average particle sizes and materials, for example, AEROSIL (Aerosil) 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9 to 0.1. In the present invention, the fine particles may be dispersed together with cellulose ester, other additives, and an organic solvent at the time of preparing the dope, but in a sufficiently dispersed state like a fine particle dispersion separately from the cellulose ester solution. It is preferable to prepare the dope. In order to disperse the fine particles, it is preferably preliminarily dispersed in an organic solvent and then finely dispersed by a disperser (high pressure disperser) having a high shearing force. After that, it is preferable to disperse in a larger amount of organic solvent, merge with the cellulose ester solution, and mix with an in-line mixer to obtain a dope. In this case, an ultraviolet absorbent may be added to the fine particle dispersion to form an ultraviolet absorbent liquid.

  The deterioration inhibitor, the ultraviolet absorber and / or the fine particles may be added together with the cellulose ester and the solvent during the preparation of the cellulose ester solution, or may be added during or after the solution preparation.

  Organic solvents useful for forming the dope according to the present invention simultaneously dissolve cellulose esters, compounds having at least two aromatic rings, and at least two aromatic rings having a planar structure, and other additives. If it does, it can be used without limitation. For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used. Particularly preferred is methyl acetate.

  In addition to the organic solvent, the dope according to the present invention preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels, facilitating peeling from the metal support, and when the proportion of alcohol is small, the role of promoting dissolution of cellulose esters in non-chlorine organic solvents There is also. Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Of these, ethanol is preferred because the dope has a relatively low boiling point, relatively low boiling point, good drying properties, and no toxicity.

  The concentration of the cellulose ester in the dope is preferably adjusted to 15 to 40% by mass, and the dope viscosity is preferably adjusted to a range of 100 to 500 poise (P) in order to obtain good film surface quality.

  A plasticizer can be added to the dope according to the present invention. As the plasticizer, phosphate ester plasticizers, phthalate ester plasticizers, glycolate plasticizers, citrate ester plasticizers, and the like can be preferably used. As phosphate plasticizers, the above-mentioned triphenyl phosphate (TPP), tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. , Diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, citrate ester, acetyl triethyl citrate, acetyl tributyl citrate, glycolate Plasticizers include alkylphthalyl alkyl glycolate, butyl oleate, methyl ricinoleate Cetyl, dibutyl sebacate, triacetin or the like can be mentioned. In the present invention, a glycolate plasticizer can be preferably used. Examples of the alkylphthalylalkyl glycolate alkyl include alkyl groups having 1 to 8 carbon atoms. Preferred glycolate plasticizers include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate (EPEG), propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl Ethyl glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, propyl phthalyl ethyl glycolate, methyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl Glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl For example, methyl glycolate, octyl phthalyl methyl glycolate, octyl phthalyl ethyl glycolate, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycol Rate and octyl phthalyl octyl glycolate are preferable, and ethyl phthalyl ethyl glycolate is particularly preferable. These alkyl phthalyl alkyl glycolates may be used in combination of two or more.

  The addition amount of the alkyl phthalyl alkyl glycolate is preferably 1 to 10% by mass with respect to the cellulose ester from the viewpoint of reducing adhesion and suppressing bleed out from the film. In the present invention, the above-mentioned other plasticizers may be mixed together with the alkylphthalylalkyl glycolate.

(Optically anisotropic layer)
The optically anisotropic layer is composed of a rod-like liquid crystalline compound or a polymerization initiator or an optional additive described later (eg, plasticizer, monomer, surfactant, cellulose ester, 1,3,5-triazine compound, chiral agent). Can be formed by applying a liquid crystal composition (coating liquid) containing, onto the alignment film and fixing the alignment of the liquid crystalline compound.

  Next, examples of the rod-like liquid crystal compound according to the present invention include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, and cyano-substituted phenylpyrimidines. Alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. The rod-like liquid crystalline compound includes a metal complex. A liquid crystal polymer containing a rod-like liquid crystalline compound in a repeating unit can also be used as the rod-like liquid crystalline compound. In other words, the rod-like liquid crystalline compound may be bonded to a (liquid crystal) polymer. For rod-like liquid crystalline compounds, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemical Review Vol. 22 Liquid Crystal Chemistry (1994) edited by the Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3. The birefringence of the rod-like liquid crystalline compound is preferably in the range of 0.001 to 0.7. The rod-like liquid crystalline compound preferably has a polymerizable group in order to fix its alignment state. Examples of the polymerizable group (Q) are shown below.

  The polymerizable group (Q) is preferably an unsaturated polymerizable group (Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated polymerizable group, ethylene Most preferably, it is a polymerizable unsaturated polymerizable group (Q1 to Q6). The rod-like liquid crystalline compound preferably has a molecular structure that is substantially symmetrical with respect to the minor axis direction. For that purpose, it is preferable to have a polymerizable group at both ends of the rod-like molecular structure. Although the example of a rod-shaped liquid crystalline compound is shown below, it is not limited to these.

  On the other hand, examples of using a discotic liquid crystal compound include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), and azacrown and phenylacetylene macrocycles. In addition, the discotic liquid crystalline compounds generally have a structure in which these are used as a mother nucleus at the center of a molecule, and a linear alkyl group, alkoxy group, substituted benzoyloxy group, etc. are linearly substituted as the linear chain. Is also included and exhibits liquid crystallinity. However, the molecule itself is not limited to these as long as it has negative uniaxiality and can give a certain orientation. In the present invention, the optically anisotropic layer formed from the discotic liquid crystalline compound does not have to be the final compound, for example, the low molecular weight discotic liquid crystalline compound is heated, Those having a group that reacts with light or the like, and consequently polymerized or cross-linked by reaction with heat, light or the like to have a high molecular weight and lose liquid crystallinity are included. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (5).

General formula (5) D (-LP) _n
Where D is a discotic core; L is a divalent linking group, P is a polymerizable group, and n is an integer from 4-12. An example of the disk-shaped core (D) is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L) and a polymerizable group (P).

  In the general formula (5), the divalent linking group (L) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. It is preferable that it is a bivalent coupling group. The divalent linking group (L) is a divalent group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, —CO—, —NH—, —O—, and —S— are combined. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10.

  Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (P). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).

L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-
L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-O-CO-
L14: -O-AL-O-CO-NH-AL-
L15: -O-AL-S-AL-
L16: -O-CO-AR-O-AL-CO-
L17: -O-CO-AR-O-AL-O-CO-
L18: -O-CO-AR-O-AL-O-AL-O-CO-
L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L20: -S-AL-
L21: -S-AL-O-
L22: -S-AL-O-CO-
L23: -S-AL-S-AL-
L24: -S-AR-AL-
The polymerizable group (P) of the general formula (5) is determined according to the type of polymerization reaction. Examples of the polymerizable group (P) are shown below.

  The polymerizable group (P) is preferably an unsaturated polymerizable group (P1, P2, P3, P7, P8, P15, P16, P17) or an epoxy group (P6, P18). More preferably, it is most preferably an ethylenically unsaturated polymerizable group (P1, P7, P8, P15, P16, P17). In General formula (5), n is an integer of 4-12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and P may differ, it is preferable that it is the same.

  When the discotic liquid crystalline compound is used, the optically anisotropic layer is a layer having negative birefringence, and the surface of the discotic structural unit is inclined with respect to the surface of the cellulose acetate film and the discotic structural unit. The angle formed between the surface and the surface of the cellulose acetate film is preferably changed in the depth direction of the optically anisotropic layer.

  The surface angle (tilt angle) of the disk-like structural unit generally increases or decreases in the depth direction of the optically anisotropic layer and with an increase in the distance from the bottom surface of the optically anisotropic layer. The tilt angle preferably increases with increasing distance. Further, the change in the inclination angle includes continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, and intermittent change including increase and decrease. I can do it. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the tilt angle includes a region where the tilt angle does not change, the tilt angle preferably increases or decreases as a whole. Further, it is preferable that the inclination angle increases as a whole, and it is particularly preferable that the inclination angle changes continuously.

  The inclination angle of the disk-shaped unit on the support side can be generally adjusted by selecting a disk-shaped liquid crystalline compound or an alignment film material or by selecting a rubbing treatment method. Further, the inclination angle of the disk-like unit on the surface side (air side) can be adjusted by selecting a discotic liquid crystalline compound or another compound used together with the discotic liquid crystalline compound. Examples of the compound used together with the discotic liquid crystalline compound include a plasticizer, a surfactant, a polymerizable monomer and a polymer. Further, the degree of change in the tilt angle can be adjusted by the same selection as described above.

  The plasticizer, surfactant, and polymerizable monomer used together with the discotic liquid crystalline compound are compatible with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound or can be aligned. Any compound can be used as long as it does not inhibit the above. Among these, polymerizable monomers (eg, compounds having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group) are preferable. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline compound.

  As the polymer used together with the discotic liquid crystalline compound, any polymer can be used as long as it is compatible with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound. A cellulose ester can be mentioned as an example of a polymer. Preferred examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. In order not to inhibit the orientation of the discotic liquid crystalline compound, the amount of the polymer added is generally in the range of 0.1 to 10% by mass with respect to the discotic liquid crystalline compound, and in the range of 0.1 to 8% by mass. It is more preferable that it is in the range of 0.1 to 5% by mass.

  The optically anisotropic layer is generally formed by applying a solution obtained by dissolving a discotic liquid crystalline compound and other compounds in a solvent onto an alignment film, drying it, and then heating it to a discotic nematic phase formation temperature, and then aligning it (disco It can be obtained by cooling while maintaining the (tick nematic phase). Alternatively, the optically anisotropic layer is formed by applying a solution obtained by dissolving a discotic liquid crystalline compound and another compound (for example, a polymerizable monomer, a photopolymerization initiator) in a solvent onto the alignment film, and then drying, It is obtained by heating to a discotic nematic phase formation temperature, polymerizing (by irradiation with UV light, etc.), and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is preferably 70 to 300 ° C, particularly preferably 70 to 170 ° C.

[Polarizing plate and liquid crystal display]
The cellulose ester film of the present invention can improve the durability of the viewing angle compensation function and the viewing angle compensation function over time. It can be used while maintaining stable performance as an expanding optical compensation film.

  The polarizing plate of the present invention will be described.

  The polarizing plate of the present invention can be produced by a general method. For example, there is a method in which the optical compensation film of the present invention is bonded to both surfaces of a polarizing film prepared by immersing and stretching in an iodine solution after alkali saponification treatment using a completely saponified polyvinyl alcohol aqueous solution. The alkali saponification treatment is a treatment in which the cellulose ester film is immersed in a strong alkaline solution at high temperature in order to improve the wetness of the aqueous adhesive and improve the adhesion.

  A conventionally well-known thing can be used as a polarizer used for the polarizing plate of this invention. For example, a film made of a hydrophilic polymer such as polyvinyl alcohol is treated with a dichroic dye such as iodine and stretched, or a plastic film such as vinyl chloride is treated and oriented. The polarizer thus obtained is bonded to a cellulose ester film.

  At this time, the optical compensation film of the present invention is used for at least one of the cellulose ester films. Another cellulose ester film can be used on the other surface. The cellulose ester film produced for the polymer film of the present invention may also be used on the other side, or a commercially available cellulose ester film (KC8UX2M, KC4UX2M, KC5UN, KC4UY, KC8UY (manufactured by Konica Minolta Opto) ) Can be used as a polarizing plate protective film on the other surface. In addition to the antiglare layer or the clear hard coat layer, the polarizing plate protective film used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, and an antifouling layer. The antireflection layer (silicon oxide layer, titanium oxide layer), antistatic layer, and antifouling layer are preferably provided by methods such as coating, sputtering, CVD, atmospheric pressure plasma CVD, and vacuum deposition.

  The liquid crystal display device of the present invention can be produced by arranging and bonding the polarizing plate of the present invention obtained on the both sides of the liquid crystal cell.

  Further, at the time of producing the polarizing plate, it is preferably bonded so that the slow axis of the optical compensation film of the present invention and the transmission axis of the polarizer are parallel as described above. As a result, light leakage at the time of black display is remarkably improved, and even a liquid crystal display device having a large screen of 15 type or more, preferably 19 type or more, has no white spots at the periphery of the screen, and the effect thereof. It is maintained for a long time, and a remarkable effect is recognized particularly in a VA liquid crystal display device. Further, the viewing angle characteristics of the liquid crystal display device adopting various driving methods such as TN, VA, OCB, and HAN can be optimized.

  Next, embodiments and effects of the present invention will be described and further described, but the present invention is of course not limited to these embodiments.

  First, methods for measuring various physical properties are described below.

(Measurement of cellulose ester film substitution degree and acetylation degree)
The degree of substitution of acetyl (DSa) and the degree of substitution of propionyl (DSp) were measured according to ASTM-D817-96. Degree of substitution (DSa) is the number of all OH groups in a cellulose ester molecule that has been reacted with acetic acid and substituted, and is expressed in glucopyranose units. A value of 3 is taken.

  The degree of acetylation is mass% of acetic acid in cellulose acetate and is calculated according to the following formula.

Degree of acetylation = {DSa × (molecular weight of CH ₃ COOH)} / {molecular weight of (C ₆ H ₁₀ O ₅ ) + DSa × (molecular weight of CH ₂ CO) + DSp × (molecular weight of CH ₃ CHCO)}
(R ₀ , R _t , slow axis direction)
The average refractive index of the sample was determined using an Abbe refractometer. Furthermore, using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), the birefringence is measured at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH, and the obtained phase difference is measured. Refractive indexes Nx, Ny, and Nz were obtained by calculation from the value and the average refractive index. At the same time, the direction of the slow axis was also measured.

(Measurement of photoelastic coefficient C (md), C (td))
Retardation (R) in the film plane is measured while applying a load to the film after film formation and drying, and this is divided by the thickness (d) of the film to obtain Δn (= R / d). Δn was determined while changing the load, a load-Δn curve was created, and the slope was taken as the photoelastic coefficient. The retardation (R) in the film plane was measured at a wavelength of 589 nm using a retardation measuring device (KOBUURA 31PR, manufactured by Oji Scientific Instruments). The photoelastic coefficients obtained by applying loads in the md and td directions of the film were C (md) Pa ⁻¹ and C (td) Pa ⁻¹ , respectively.

(Dimensional change rate)
The film was marked with a cutter so as to have a width of about 10 cm, and allowed to stand at 23 ° C. and 50% RH for 24 hours, and then the length was measured. Thereafter, the film was treated in an environment of 80 ° C. and 90% RH for 50 hours. After the treatment, the film was again allowed to stand for 24 hours or more in an environment of 23 ° C. and 50% RH, and the distance was measured again.

  The dimensional change rates S (md) (%) and S (td) (%) in the md and td directions were determined from the changes before and after the treatment.

(Viewing angle characteristics and durability)
For the evaluation of viewing angle characteristics, the transmitted light amount during black display and white display was measured using EZ-contrast manufactured by ELDIM. The viewing angle was evaluated by calculating contrast = (transmitted light amount during white display) / (transmitted light amount during black display).

The durability of the viewing angle function was evaluated by measuring the viewing angle characteristics before and after 500 h treatment at 60 ° C. and 90% RH, and observing the change in angle indicating the viewing angle of contrast 10.
Evaluation ○: No change in top, bottom, left and right △: Change in viewing angle of 2 ° or more and less than 5 ° in either up, down, left or right direction ×: Change in viewing angle of 5 ° or more in either direction of top, bottom, left or right In this case In the invention, ○ and Δ are practical.

Example 1
(Preparation of dope A)
1 part by weight Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) and 9 parts by weight of ethanol are mixed in a container and finely dispersed with a Manton Gorin disperser having a shearing force of 30 MPa to form a fine particle stock solution. The mixture was diluted with 9 parts by mass of methylene chloride to obtain a filler dispersion dilution.

  In an amount of 1.2 parts by mass of methylene chloride, 1.2 parts by mass of an ultraviolet absorber and 0.7 parts by mass of a cellulose ester (described in A in Table 1) are dissolved, and 3.0 parts by mass of the filler dispersion dilution. Was added and stirred to obtain a filler additive solution. The following cellulose ester solution composition was introduced into another pressure-resistant airtight container, and a cellulose ester solution was prepared by a high temperature dissolution method. The pressure inside the pressure-tight airtight container was set to 0.2 MPa and dissolved while stirring. Next, 0.04 parts by mass of the filler addition solution was poured into a cellulose ester solution having a mass of 1.0, and the mixture was sufficiently stirred and allowed to stand overnight. Thereafter, the solution was added to Azumi Filter Paper NO. Filtered using 244 to prepare Dope A.

(Cellulose ester solution composition)
Cellulose ester (described in A in Table 1) 100 parts by mass TPP (triphenyl phosphate) 8.5 parts by mass EPEG (ethyl phthalylethyl glycolate) 2 parts by mass Methylene chloride 300 parts by mass Ethanol 57 parts by mass Preparation)
The cellulose ester at the time of preparation of the dope A (described in A in Table 1) was replaced with cellulose ester B having an acetylation degree of 60%, and 6 parts by mass of the exemplified compound A-7 was added to 100 parts by mass of the cellulose ester. A dope B was prepared in the same manner as the dope A preparation.

(Preparation of dope C)
In the preparation of the dope B, the dope C was prepared in the same manner except that the exemplified compound A-7 was not added.

(Preparation of optically compensated cellulose ester film)
Using the dope A, the dope temperature was adjusted to 35 ° C. and the support temperature was 35 ° C., and cast from a die onto a stainless steel support belt. The drying air temperature on the support was 40 ° C. Thereafter, the support temperature was set to 20 ° C., and the web was peeled from the support with a residual solvent amount of 80% by mass. Next, stretching was performed under the conditions of a stretching ratio of 1.3 times, a web temperature of 80 ° C. during stretching, and a web residual solvent of 20% during stretching while holding both ends of the web with clips using a tenter. The web was further dried while relaxing in the width direction with 500 rolls having a transport tension of 100 N, a drying temperature of 100 ° C., and a roll-shaped optically compensated cellulose ester film D was obtained.

(Production of viewing angle compensation integrated polarizing plate (optical compensation polarizing plate))
Each of the roll-shaped optically compensated cellulose ester films D was treated in a 2 mol / l sodium hydroxide aqueous solution at 60 ° C. for 2 minutes, washed with water, and then dried at 100 ° C. for 10 minutes to produce an alkali saponified polarizing plate protective film. did.

  Separately, a 120 μm-thick polyvinyl alcohol film was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched 4 times at 50 ° C. to produce a polarizer (polarizing film).

  A polarizing plate protective film for polarizing plate E was bonded to both sides of the polarizer using a 5% aqueous solution of fully saponified polyvinyl alcohol as an adhesive to produce viewing angle compensation integrated polarizing plate E. In addition, it bonded so that the transmission axis of a polarizer and the slow axis of an optical compensation cellulose-ester film might become parallel at this time.

  Further, in the production of the roll-shaped optically compensated cellulose ester film D, a roll-shaped optically compensated cellulose ester film F (Comparative Example) was obtained in the same manner except that the film after width stretching was dried without being relaxed.

  Thereafter, a viewing angle compensation-integrated polarizing plate G (Comparative Example) was prepared by bonding with a polarizer in the same manner as described above.

  In the production of the roll-shaped optically compensated cellulose ester film D, an optically compensated cellulose ester film H, which was similarly subjected to mild drying using the dope B instead of the dope A, was produced.

  In the production of the roll-shaped optically compensated cellulose ester film F, a roll-shaped optically compensated cellulose ester film I (Comparative Example) was produced using the dope B instead of the dope A.

  Using the obtained H and I, a viewing angle compensation integrated polarizing plate M (present invention) and N (comparative example) were produced and evaluated.

  Moreover, the optical compensation cellulose-ester film J which carried out the mild drying using dope C was produced. Using the obtained J, a viewing angle compensation integrated polarizing plate K (invention) was prepared and evaluated.

  Table 2 below summarizes the physical properties of the viewing angle compensation cellulose ester film and the performance of the optical compensation polarizing plate using it.

  As described above, the viewing angle compensation integrated polarizing plates E, M, and K of the present invention have an optical compensation film of | S (md) |> | S (td) | and C (md) <C (td). In the direction of large dimensional change, the photoelastic coefficient is small and the influence on the viewing angle is small. As a result, the viewing angle durability evaluation can achieve ○.

  However, in the optical compensation films of the viewing angle compensation integrated polarizing plates G and N of the comparative example, the photoelastic coefficient in the direction in which the dimensional change is large causes a large change in the phase difference, so that sufficient viewing angle durability cannot be obtained. It was.

  However, the viewing angle compensation integrated polarizing plate K has a problem in that the haze of the film is high.

Example 2
Alkyl-modified polyvinyl alcohol (0.1 μm) was applied to one surface of the viewing angle compensation integrated polarizing plates E and G prepared in Example 1 and dried with hot air at 65 ° C. A rubbing treatment was performed in parallel with the absorption axis direction of the polarizer to form an alignment layer.

Further, a solution LC-1 having the following composition was applied on the alignment layer. Alignment and fixation with 450 mJ / cm ³ UV light under conditions of oxygen concentration of 0.1% or less, coated with an optical anisotropic layer with nematic hybrid structure on one side, compatible with viewing angle compensation integrated polarizing plates E and G Thus, viewing angle compensation polarizing plates L and O were obtained. In addition, said process was performed through roll conveyance.

  The optical anisotropic layer was laminated so that it was disposed on the glass surface side of the liquid crystal cell, and evaluation was performed in the same manner as in Example 1 above. As a result, the viewing angle compensation polarizing plate L of the present invention was evaluated as ◯ in the durability evaluation of viewing angle compensation, but the comparative viewing angle compensation polarizing plate O was evaluated as x.

(LC-1 composition)
MEK (methyl ethyl ketone) 88 parts by weight Compound 1 3 parts by weight Compound 2 3 parts by weight Compound 3 3 parts by weight Compound 4 2 parts by weight Irgacure 369 (manufactured by Ciba Specialty Chemicals) 1 part by weight

Example 3
After coating alkyl-modified polyvinyl alcohol (0.1 μm) on one surface of viewing angle compensation integrated polarizing plate E, G, M, N obtained in Example 1, and drying with hot air of 65 ° C. Then, rubbing treatment was performed in parallel with the film longitudinal direction (absorption axis direction of the polarizer) to form an alignment layer.

  The following discotic liquid crystalline compound 41.01 g, ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 g, cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co., Ltd.) ) 0.90 g, cellulose acetate butyrate (CAB531-1, Eastman Chemical) 0.23 g, photopolymerization initiator (Irgacure 907, Ciba Geigy) 1.35 g, sensitizer (Kayacure DETX, Nippon Kayaku) 0.45 g (manufactured by Yakuhin Co., Ltd.) was dissolved in 102 g of methyl ethyl ketone to prepare a coating solution.

  Next, the coating solution was applied on the alkyl-modified polyvinyl alcohol alignment layer with a # 3.6 wire bar. This was heated in a constant temperature zone of 130 ° C. for 2 minutes to orient the discotic compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high pressure mercury lamp in an atmosphere of 60 ° C. to polymerize the discotic compound. Then, it stood to cool to room temperature.

  Optical compensation polarizing plates P, Q, R, and S coated with an optically anisotropic layer corresponding to the optical compensation cellulose ester films D, F, H, and I were prepared by the above method. When evaluated in the same manner as in Example 2, the optical compensation polarizing plates P and R of the present invention were able to achieve the viewing angle compensation durability improving effect, but about Q and S of Comparative Examples outside the present invention. The viewing angle durability was evaluated as x, and the effect of the present invention was confirmed even in this case.

Claims (9)

When the photoelastic coefficients in the longitudinal and width directions of the cellulose ester film are C (md) and C (td), respectively, the respective values are in the range of 1 × 10 ⁻⁹ to 1 × 10 ⁻¹³ Pa ⁻¹ . And C (md) <C (td), and the retardation R ₀ in the cellulose ester film surface defined by the following formula (I) is in the range of 20 to 70 nm. retardation R _t the thickness direction of the cellulose ester film as defined in II) is 70～400Nm, longitudinal of the film, 80 ° C. in the width direction, before and after subjected to 50 hours at 90% RH environmental conditions When the dimensional change rates of S are S (md) and S (td), respectively, the respective values are in the range of −1 to 1%, and the relationship of | S (md) |> | S (td) | An optical compensation film characterized by satisfying Film support.
(I) R ₀ = (nx−ny) × d
(II) R _t = {(nx + ny) / 2−nz} × d
(In the formula, nx is the refractive index in the slow axis direction (width direction) in the film plane, ny is the refractive index in the fast axis direction (longitudinal direction) in the film plane, and nz is the film. The refractive index in the thickness direction of the film, and d is the thickness of the film.) An optical compensation film using the optical compensation film support according to claim 1. The optical compensation film according to claim 2, wherein at least one optically anisotropic layer is provided on the support for the optical compensation film according to claim 1. The optical compensation film according to claim 2 or 3, wherein the cellulose ester used for the support for an optical compensation film according to claim 1 satisfies the following formulas (IV) and (V) simultaneously.
(IV) 2.55 ≦ X + Y ≦ 2.85
(V) 1.4 ≦ X ≦ 2.85
(However, X is a substitution degree of an acetyl group, Y is a substitution degree of a propionyl group and / or a butyryl group.) The acetylation degree of the cellulose ester film used for the optical compensation film support according to claim 1 is in the range of 59.0 to 61.5%, and at least two aromatic rings are contained with respect to 100 parts by mass of the cellulose ester. The optical compensation film according to any one of claims 2 to 4, comprising 0.1 to 20 parts by mass of a compound having two. The optical compensation film according to any one of claims 2 to 4, further comprising an optically anisotropic layer formed by fixing a nematic hybrid alignment structure. The optical compensation film according to any one of claims 2 to 4, further comprising an optically anisotropic layer containing a discotic liquid crystalline compound. A viewing angle compensation-integrated polarizing plate comprising two protective films and a polarizer, wherein at least one of the protective films is the optical compensation film according to any one of claims 2 to 7, and the optical compensation film A viewing angle compensation-integrated polarizing plate, wherein the slow axis of the cellulose ester film of the support for an optical compensation film and the transmission axis of the polarizer are substantially parallel. A liquid crystal display device using the viewing angle compensation integrated polarizing plate according to claim 8.