JP2006299114A - Cellulose acylate film for use in optics, polarizing plate, and liquid crystal display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose acylate film which is excellent in the optical performance, the uniformity in the plane and which has little deterioration in the quality of streak indication even under the environmentally forced condition; an optical compensation film formed of this cellulose acylate film; and a liquid crystal display unit. <P>SOLUTION: In a cellulose acylate film having as a polymer component of the film constituents the cellulose acylate that is such a fatty acid ester of a cellulose as is obtained by displacing the hydroxy groups of a cellulose with at least one kind of a 3 or more C-acyl groups or -acetyl groups, the cellulose acylate film for use in optics is characterized by satisfying in the S(MD) and S(TD) numerical formula (1): S(MD)≤S(TD), wherein S(MD) and S(TD) are respectively a shrinkage factor (unit:%) in the film casting direction (MD) and film casting width direction (TD) of the film at an elapsed time of 120 hours under an environment of 60°C and 90% RH. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

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

  Cellulose acylate films are used in various photographic materials and optical materials because of their toughness, flame retardancy, and optical isotropy. The cellulose acylate film is generally produced by a solvent cast method. In the solvent cast method, a solution (dope) in which cellulose acylate is dissolved in a solvent is cast on a support, and the solvent is evaporated by drying to form a film. In the solvent cast method, a film having excellent flatness can be produced.

  In the liquid crystal display device, using an optical compensation sheet for widening the viewing angle, improving image coloring, and improving contrast is a widely known technique as described above. Especially, the film which added the low molecular weight compound with high planarity in the cellulose ester is particularly useful since the retardation can be adjusted in a wide range, and disclosed in Patent Documents 2 and 3.

When the cellulose acylate film is used as an optical compensation film, a functional additive may be added to the cellulose acylate film in order to impart an optical function. On the other hand, as an evaluation method for the humidity and heat of a liquid crystal display device, the environmental forcing test of the liquid crystal display device and each member used in it is performed under high temperature and high humidity conditions, not in the environment near normal room temperature. Widely known. For example, 60 ° C. and 90% RH are known as a durability test for polarizing plates. When the optical compensation film is aged for a long time under these conditions, the dimensional change caused by the relaxation of residual stress and residual strain occurs. When the film is used in a liquid crystal display device, the display quality deteriorates (viewing angle). And a decrease in contrast and light leakage in the area around the panel.
Japanese Patent No. 2747789 JP 2003-62899 A JP 2000-1111914 A

  An object of the present invention is to provide a cellulose acylate film excellent in optical performance and in-plane uniformity, and having little deterioration in display quality even under environmentally forced conditions, an optical compensation film comprising a cellulose acylate film, and a liquid crystal display device Is to provide.

  In order to achieve the above-mentioned problems, the present inventors have conducted a study, and the deterioration of the display quality of the liquid crystal display device in the high-temperature and high-humidity environmental forced test is not simply caused by the change in the dimensions of the optical compensation film. It was thought to be brought about by the composite of dimensional changes of various constituent members of the polarizing plate and the optical compensation film. In particular, the inventor has focused on the change in the dimensions of the polarizer in the polarizing plate among these components. The polarizer of the polarizing plate generally stretches polyvinyl alcohol several times and puts iodine in it, so that the iodine is oriented, and then the orientation of polyvinyl alcohol and iodine is fixed by boric acid treatment. In general, polyvinyl alcohol also contracts under a forced environment condition of high temperature and high humidity, and shrinkage rate anisotropy is generally present.

  On the other hand, the bonding angle between the optical compensation film and the polarizing plate needs to be changed according to various liquid crystal panels. In the vertical alignment type liquid crystal display device, the stretching direction of the polarizer of the polarizing plate and the stretching direction of the optical compensation film are Orthogonal. By providing anisotropy in the shrinkage direction of the optical compensation film after the environmental compulsory test, the present inventors can balance this with the shrinkage of the polarizer of the polarizing plate so that the display quality of the liquid crystal display device does not deteriorate. I thought. As a result of intensive studies, the inventor of the present invention found a balance in shrinkage rate anisotropy in the casting direction and casting width direction of the optical compensation film with little deterioration in the display quality of the liquid crystal display device in the environmental forcing test. It came to discover the manufacturing conditions for implement | achieving such shrinkage | contraction rate anisotropy.

  Specifically, the present invention has the following configuration.

(1) As a polymer component constituting a film, cellulose acylate is a cellulose fatty acid ester obtained by substituting the hydroxyl group of cellulose with at least one group out of an acyl group having 3 or more carbon atoms and an acetyl group. The rate of shrinkage in the casting (MD) direction and the casting width (TD) direction when aged for 120 hours in an environment of 60 ° C. and 90% RH. S (MD) and S (TD) satisfy the following mathematical formula (1) where S is (MD) and S (TD), respectively.
Formula (1): S (MD) ≦ S (TD)

(2) The optical cellulose acylate film according to (1), wherein the S (MD) and S (TD) satisfy the following mathematical formulas (2) to (4).
Formula (2): S (TD) = S (MD) × 5/8 + C
Formula (3): −0.4 ≦ S (MD) ≦ 0.2
Formula (4): −0.125 ≦ C ≦ 0.125
[In the formula, C is a heat shrinkage adjustment coefficient (unit:%). ]

(3) Starting from a film raw material as a starting material, a casting process, a film peeling process, a transport process, a process of holding both ends of a web with a tenter clip, a stretching process, a relaxation process, and a process of releasing the holding by a tenter clip A cellulose acylate film manufactured by a manufacturing method including: a distance from a position where the film is peeled off to a position where the tenter clip is released is set to L0, and from the position where the film is peeled off, When the distance from the position where stretching is started is L1, and the distance from the position where the film is peeled off to the position where the stretching process is substantially finished is L2, the following formula (5) is set between L0, L1 and L2. ~
The cellulose acylate film for optical use according to (2), which is produced so as to satisfy the relationship (7).
Formula (5): 0.20 ≦ L1 / L0 ≦ 0.80
Formula (6): 0.50 ≦ L2 / L0 ≦ 0.95
Formula (7): L1 ≦ L2

  (4) In the manufacturing method, the film is manufactured under such a condition that the amount of change in volatile content based on the dry amount of the film between the position where stretching is substantially started and the position where the relaxation process is substantially completed is 3 to 90%. The optical cellulose acylate film as described in (3).

(5) In the cellulose acylate, the substitution degree A of the acetyl group substituted by the hydroxyl group of cellulose and the substitution degree B of the acyl group having 3 or more carbon atoms satisfy the following formula (I) and stretched: In the step, the optical cellulose acylate film according to any one of (1) to (4), which is substantially stretched by 10% or more in the casting direction and / or the casting width direction.
Formula (I): 2.0 ≦ A + B ≦ 3.0

(6) The substitution degree of the 2-position hydroxyl group of the cellulose acylate with the acyl group is DS2, the substitution degree of the 3-position hydroxyl group with the acyl group is DS3, and the substitution degree of the 6-position hydroxyl group with the acyl group is DS6. When the optical cellulose acylate film according to any one of (1) to (5) is satisfied, the following mathematical formulas (VI-a) and (VI-b) are satisfied.
Formula (VI-a): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI-b): DS6 / (DS2 + DS3 + DS6) ≧ 0.315
(7) The optical cellulose acylate film according to any one of (1) to (6), wherein the acyl group includes a butanoyl group.
(8) The cellulose acylate film for optical use according to any one of (1) to (7), which comprises a propionyl group as an acyl group and has a substitution degree B of 0.6 or more.

(9) Any of (1) to (8), wherein the front retardation Re (λ) of the film and the retardation Rth (λ) in the thickness direction satisfy the following formulas (XI) and (XII): An optical cellulose acylate film according to claim 1.
Formula (XI): 30 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
Formula (XII): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm

(10) The cellulose acylate film for optical use according to (9), wherein the Re ₍₅₉₀₎ and Rth ₍₅₉₀₎ satisfy the following formulas (XIII) and (XIV).
Formula (XIII): 40 nm ≦ Re ₍₅₉₀₎ ≦ 100 nm
Formula (XIV): 160 nm ≦ Rth ₍₅₉₀₎ ≦ 300 nm

(11) The optical cellulose acylate film as described in any one of (1) to (10), which contains at least one retardation developing agent comprising a rod-like or discotic compound.
(12) The optical cellulose acylate film according to any one of (1) to (11), which contains at least one of a plasticizer, an ultraviolet absorber, and a peeling accelerator.

(13) The optical cellulose acylate film according to any one of (1) to (12), wherein the film has a thickness of 40 to 180 μm.
(14) the difference between Re ₍₅₉₀₎ value at 25 ° C. Re ₍₅₉₀₎ at 10% RH values and _{25 ℃ 80% RH ΔRe (Re} (590) 10% RH-Re (590) RH 80%),
Is 0 to 10 nm, the difference between _{Rth (590)} value in the _{Rth (590)} value and 25 ° C. 80% RH at _{25 ℃ 10% RH ΔRth (590} ) (Rth (590) 10% RH-Rth (590) 80 % RH) is 0 to 30 nm, The optical cellulose acylate film according to any one of (1) to (13).
(15) The optical cellulose acylate film according to any one of (1) to (14), which is stretched by a uniaxial stretching method, a simultaneous biaxial stretching method, or a sequential biaxial stretching method.

(16) Re ₍₅₉₀₎ and Rth ₍₅₉₀ ) at 25 ° C. and 60% RH satisfy the following mathematical formulas (A) to (C): The optical use according to any one of (1) to (15) Cellulose acylate film.
Formula (A): 40 ≦ Re ₍₅₉₀₎ ≦ 145
Formula (B): Rth ₍₅₉₀₎ = a- _5.9 Re ₍₅₉₀₎
Formula (C): 500 ≦ a ≦ 670
[Wherein, Re ₍₅₉₀₎ is a front retardation value (unit: nm) at a wavelength of ₅₉₀ nm, and Rth ₍₅₉₀₎ is a retardation value (unit: nm) in the film thickness direction at a wavelength of 590 nm. Further, a is an adjustment factor (unit: nm) of optical characteristics. ]

(17) Film calculated as R (%) = (Rmax−Rmin) / Rave × 100 where the maximum value, minimum value, and average value of the film thickness in the width direction are Rmax, Rmin, and Rave, respectively. The cellulose acylate film according to any one of (1) to (16), wherein the thickness distribution R is adjusted to 0 to 8%.
(18) The cellulose acylate film for optical use according to any one of (1) to (17), wherein the distribution of Re ₍₅₉₀₎ is adjusted to 5% or less.
(19) The optical cellulose acylate film according to any one of (1) to (18), wherein the distribution of Rth ₍₅₉₀₎ is adjusted to 10% or less.

(20) A polarizing plate, wherein at least one of the two protective films of the polarizer comprises the optical cellulose acylate film according to any one of (1) to (19).
(21) The single plate transmittance TT, the parallel transmittance PT, the orthogonal transmittance CT, and the polarization degree P at 25 ° C. and 60% RH satisfy at least one of the following formulas (a) to (d). The polarizing plate as described in (20).
(A) 40.0 ≦ TT ≦ 45.0
(B) 30.0 ≦ PT ≦ 40.0
(C) CT ≦ 2.0
(D) 95.0 ≦ P

(22) T ₍₃₈₀₎ , T ₍₄₁₀₎ , T ₍₇₀₀₎ are represented by the following formulas (e) to (g) when the orthogonal transmittance at 25 ° C. 60% RH and wavelength λ is T (λ). The polarizing plate according to (20) or (21), wherein at least one is satisfied.
(E) T ₍₃₈₀₎ ≦ 2.0
(F) T ₍₄₁₀₎ ≦ 1.0
(G) T ₍₇₀₀₎ ≦ 0.5
(23) The amount of change ΔCT and the amount of change in polarization degree ΔP of the orthogonal single plate satisfying at least one of the following formulas (j) and (k) when left at 60 ° C. and 95% RH for 500 hours. The polarizing plate as described in any one of (20) to (22).
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
(However, the amount of change is the value obtained by subtracting the measured value before the test from the measured value after the test.)
(24) Any one of (20) to (23), wherein at least one of a hard coat layer, an antiglare layer, and an antireflection layer is provided on the surface of one protective film of the polarizer. The polarizing plate as described in.

(25) A liquid crystal display device comprising at least one of the optical cellulose acylate film according to (1) to (19) and the polarizing plate according to any one of (20) to (24). .
(26) An OCB or VA mode liquid crystal display device using any one of the polarizing plates according to (20) to (24) above and below a liquid crystal cell.
(27) A VA mode liquid crystal display device using any one of the polarizing plates according to (20) to (24) on a backlight side.

According to the present invention, in the optical compensation film comprising a cellulose acylate film and a cellulose acylate film, by controlling the thermal shrinkage in the MD direction and the TD direction, there is little deterioration in the display quality of the liquid crystal display device in the environmental forced test, and A planar film excellent in optical uniformity within the film plane can be efficiently provided with high productivity. In addition, a cellulose acylate film having a high retardation value and excellent optical uniformity within the film plane can be obtained.
The liquid crystal display device of the present invention provided with the optical cellulose acylate film or polarizing plate of the present invention exhibits good display characteristics with little deterioration in display quality even after an environmental forced test.

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

The present invention relates to a cellulose acylate film comprising a cellulose acylate in which a polymer component constituting a film is a cellulose fatty acid ester obtained by substituting a hydroxyl group of cellulose with an acetyl group or an acyl group having 3 or more carbon atoms. There,
The shrinkage rate (unit:%) in the casting (MD) direction and the casting width (TD) direction of the film when aged for 120 hours in an environment of 60 ° C. and 90% RH is S (MD) and S (TD), respectively In this case, S (MD) and S (TD) satisfy the following mathematical formula (1).
Formula (1): S (MD) ≦ S (TD)

The shrinkage rate S (MD) in the casting (MD) direction and the shrinkage rate S (TD) (%) in the casting width (TD) direction of the film after aging for 120 hours in an environment of 60 ° C. and 90% RH are obtained. A method will be described.
A 50 mm x 250 mm sample cut out from the protective film is conditioned for 2 days or more in an atmosphere of 25 ° C and 60% RH, and then casted with an automatic pin gauge (manufactured by Shinto Kagaku Co., Ltd.). 6 mmφ holes are formed at intervals of 200 mm so as to be parallel to each other, and the original size (L1) of the interval is measured to a minimum scale of 1/1000 mm. Then, a thermo treatment is performed at 60 ° C. and 90% RH for 120 hours, and after adjusting the humidity to 25 ° C. and 60% RH for 24 hours, the dimension (L2) of the punch interval is measured. The shrinkage rate (%) in the casting direction is obtained by the following formula.
Casting direction dimension change rate S (MD) = {(L2−L1) / L1} × 100
Further, the shrinkage rate (%) S (TD) in the casting direction can be obtained by the same method as described above except that a hole by an automatic pin gauge is formed in the casting width direction at the time of forming the protective film.

In the present invention, it is preferable that the S (MD) and S (TD) satisfy the following formulas (2) to (4).
Formula (2): S (TD) = S (MD) × 5/8 + C
Formula (3): −0.4 ≦ S (MD) ≦ 0.2
Formula (4): −0.125 ≦ C ≦ 0.125
[In the formula, C is a heat shrinkage adjustment coefficient (unit:%). ]

  The reason is not clear, but by setting S (MD) and S (TD) in the above ranges, the stress and strain remaining in the optical compensation film are well balanced with the thermal shrinkage of the polarizer in the environmental forcing test. By doing so, it is considered that the deterioration of display quality as a liquid crystal display device can be suppressed.

  In the formula (3), S (MD) is preferably −0.40% or more and 0.20% or less, more preferably −0.30% or more and 0.10% or less, and further preferably −0.25. % Or more and 0.05% or less.

  C represents a heat shrinkage adjustment coefficient (unit:%). C is preferably −0.1 to 0.125, more preferably −0.05 to 0.12, and further preferably 0 to 0.110.

In addition, although the preferable manufacturing method of the optical cellulose acylate of this invention is mentioned later, it is preferable to manufacture especially with the following method.
Production starting from film raw material, including casting process, film peeling process, conveying process, holding both ends of web with tenter clip, stretching process, relaxation process, releasing tenter clip The method is preferred. FIG. 1 shows a solution film forming process diagram used in the present invention, and FIG. 2 shows a schematic plan view of a width direction stretching device (tenter) used in the present invention.
In particular, in the above manufacturing method, the distance from the position where the film was peeled off (4 in FIG. 1) to the position where the holding by the tenter clip was released (15 in FIG. 2) was L0, and the position where the film was peeled off (FIG. 1). The distance from the middle 4) to the position (12 in FIG. 2) from which stretching is substantially started is L1, and the position at which the stretching process is substantially finished from the position (4 in FIG. 1) where the film is peeled off (FIG. 2). When the distance to the middle 13) is L2, it is preferably manufactured so as to satisfy the relationships of the following formulas (5) to (7) between L0, L1, and L2.
Formula (5): 0.20 ≦ L1 / L0 ≦ 0.80
Formula (6): 0.50 ≦ L2 / L0 ≦ 0.95
Formula (7): L1 ≦ L2

  Here, among the above, “the position where stretching is substantially started” means a position where the width is increased by at least 1% as a width-enlarging ratio after the transporting process and wider than the width of the film when cast from the casting die. pointing. That is, 12 positions in FIG. 2 are shown.

  Further, among the above, “a position at which the stretching process is substantially finished” means a position where at least 0.5% of the width is reduced from the maximum widening in the relaxation process after the maximum widening width is achieved in the stretching process. That is, 13 positions in FIG. 2 are shown.

  L1 / L0 is preferably 0.20 or more and 0.50 or less, more preferably 0.20 or more and 0.40 or less, and further preferably 0.20 or more and 0.30 or less.

  L2 / L0 is preferably 0.50 or more and 0.85 or less, 0.50 or more and 75 or less, and more preferably 0.50 or more and 0.70 or less.

  In the said manufacturing method, it manufactures on the conditions that the dry quantity reference | standard volatile matter variation | change_quantity of the film between the position which starts extending | stretching substantially from the position which complete | finishes a relaxation process will be 3% or more and 90%. It is preferable.

  The “substantially starting position of stretching” has the same meaning as the “substantially starting position of stretching” described above.

  The relaxation process is the process of reducing the widened width in the stretching process. The “position where the relaxation process is substantially finished” is the end of the film width reduction in the relaxation process and maintaining a certain film width. The position where you started. That is, the position 14 is shown in FIG.

  The amount of change in the volatile matter based on the dry amount of the film between the position at which stretching is substantially started and the position at which the relaxation process is substantially completed is controlled by the air volume, temperature, humidity, L1 / L0, L2 / L0, etc. during stretching. By doing so, it can be controlled to a desired ratio.

  The amount of change in the dry reference volatile content is preferably 3% to 80%, more preferably 3% to 70%, and still more preferably 3% to 50%.

[Cellulose acylate]
The specific cellulose acylate used in the present invention will be described in detail. In the present invention, two or more different cellulose acylates may be mixed and used.
The specific cellulose acylate is a fatty acid ester of cellulose obtained by substituting a hydroxyl group of cellulose with an acetyl group and an acyl group having 3 or more carbon atoms, and preferably the degree of substitution of the cellulose with a hydroxyl group is represented by the following formula: Satisfies (I).
Formula (I): 2.0 ≦ A + B ≦ 3.0
Here, in the formula, A and B represent the substitution degree of the acyl group substituted with the hydroxyl group of cellulose, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 or more carbon atoms.
Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with acyl groups. The degree of acyl substitution means the proportion of cellulose esterified at each of the 2-position, 3-position and 6-position (100% esterification has a substitution degree of 1).
When the substitution degree of the 2-position hydroxyl group of the cellulose acylate with an acyl group is DS2, the substitution degree of the 3-position hydroxyl group with an acyl group is DS3, and the substitution degree of the 6-position hydroxyl group with an acyl group is DS6, The following mathematical formulas (VI-a) and (VI-b) are preferably satisfied together with a mathematical formula (VI) relating to a thermal expansion coefficient described later.
Formula (VI-a): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI-b): DS6 / (DS2 + DS3 + DS6) ≧ 0.315

In the present invention, the total substitution degree (A + B) of hydroxyl groups A and B is preferably 2.0 to 3.0, more preferably 2.2 to 2, as shown in the above formula (I). 0.9, and particularly preferably 2.40 to 2.85. Further, the substitution degree of B may be zero. When it is not 0, it is preferably 0.9 or more, particularly preferably 1.3 or more.
When A + B is 2.0 or more, hydrophilicity is weak and it is difficult to be affected by environmental humidity.
When B is 0 and cellulose acetate is used, it is easily affected by environmental humidity. However, the influence of environmental temperature is smaller than the case where the linear thermal expansion coefficient described later is not 0, and is displayed on the liquid crystal display device. Occurrence of unevenness when it is made to be suppressed.
Further, 28% or more of B is preferably the substitution degree of the 6-position hydroxyl group, more preferably 30% or more is the substitution degree of the 6-position hydroxyl group, more preferably 31% or more, and particularly preferably 32% or more. The substitution degree of the 6-position hydroxyl group is preferred.
Furthermore, the total substitution degree of A and B at the 6-position hydroxyl group of cellulose acylate is preferably 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. With these cellulose acylate films, a solution for preparing a film having preferable solubility and filterability can be produced, and a good solution can be produced even in a non-chlorine organic solvent. Furthermore, it becomes possible to produce a solution having a low viscosity and good filterability.

  The acyl group having 3 or more carbon atoms may be an aliphatic group or an aromatic hydrocarbon group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. These preferred B include propionyl, butanoyl, keptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl , Naphthylcarbonyl, cinnamoyl group and the like. Among these, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl group and the like are preferable. Particularly preferred are propionyl and butanoyl groups. In the case of a propionyl group, the substitution degree B is preferably 0.6 or more.

  Specific examples of cellulose acylate include cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

[Method of synthesizing cellulose acylate]
The basic principle of the cellulose acylate synthesis method is described in Mita et al., Wood chemistry, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst.
Specifically, cellulose raw materials such as cotton linter and wood pulp are pretreated with an appropriate amount of acetic acid, and then put into a pre-cooled carboxylic acid mixture to be esterified to complete cellulose acylate (2nd, 3rd and 6th). The total degree of acyl substitution at the position is approximately 3.00). The carboxylated mixed solution generally contains acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. The carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system. After completion of the esterification reaction, a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc) is used for hydrolysis of excess carboxylic anhydride remaining in the system and neutralization of a part of the esterification catalyst. Of carbonate, acetate or oxide). Next, the obtained complete cellulose acylate is saponified and aged by maintaining it at 50 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain the desired degree of acyl substitution and polymerization. The cellulose acylate having a degree is changed. When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized with the neutralizing agent as described above, or in water or dilute sulfuric acid without neutralization. The cellulose acylate solution is added (or water or dilute sulfuric acid is added to the cellulose acylate solution), the cellulose acylate is separated, washed and stabilized, and the like. Can be obtained.

In the cellulose acylate film, the polymer component constituting the film is preferably substantially composed of the specific cellulose acylate. “Substantially” means 55% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more) of the polymer component.
Cellulose acylate is preferably used in the form of particles. 90% by mass or more of the particles to be used preferably have a particle diameter of 0.5 to 5 mm. Moreover, it is preferable that 50 mass% or more of the particle | grains to be used have a particle diameter of 1-4 mm. The cellulose acylate particles preferably have a shape as close to a sphere as possible.
The degree of polymerization of cellulose acylate preferably used in the present invention is a viscosity average degree of polymerization, preferably 200 to 700, more preferably 250 to 550, still more preferably 250 to 400, and particularly preferably 250 to 350. . The average degree of polymerization can be measured by Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Society, Vol. Further details are described in JP-A-9-95538.

When the low molecular component is removed, the average molecular weight (polymerization degree) is increased, but the viscosity is lower than that of ordinary cellulose acylate. Therefore, the cellulose acylate from which the low molecular component is removed is useful. . Cellulose acylate having a small amount of low molecular components can be obtained by removing low molecular components from cellulose acylate synthesized by a usual method. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent. In addition, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose acylates. When the amount of the sulfuric acid catalyst is in the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized. When used in the production of cellulose acylate, the water content is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly 0.7% by mass or less. In general, cellulose acylate contains water and generally has a water content of 2.5 to 5% by mass. In order to obtain this moisture content, drying is preferable, and the method is not particularly limited as long as the desired moisture content is achieved.
The raw material cotton of cellulose acylate and the synthesis method thereof are disclosed in JIII Journal of Technical Disclosure No. 2001-1745 (issued March 15, 2001, Invention Association) p. Raw material cotton and synthesis methods described in detail in 7-12 can be employed.

  The cellulose acylate film of the present invention can be obtained by forming a film using a solution prepared by dissolving the specific cellulose acylate and, if necessary, an additive in an organic solvent.

[Additive]
In the present invention, examples of the additive that can be used in the cellulose acylate solution include a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a retardation (optical anisotropy) developing agent, fine particles, a peeling accelerator, and red. An external absorbent etc. can be mentioned. In the present invention, it is preferable to use a retardation developer. Moreover, it is preferable to use 1 or more types of a plasticizer, a ultraviolet absorber, and a peeling accelerator.
They may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, ultraviolet absorbers having a melting point of 20 ° C. or lower and 20 ° C. or higher can be mixed and used, and a plasticizer can also be mixed and used, for example, as described in JP-A-2001-151901.

As the ultraviolet absorber, any type can be selected according to the purpose, and a salicylic acid ester-based, benzophenone-based, benzotriazole-based, benzoate-based, cyanoacrylate-based, nickel complex-based absorber or the like is used. Preferred are benzophenone series, benzotriazole series, and salicylic acid ester series. Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4-methoxybenzophenone, 2, 2′-di-hydroxy-4,4′-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4- (2-hydroxy-3- And methacryloxy) propoxybenzophenone. As a benzotriazole ultraviolet absorber, 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-butylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5 Examples include chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, and the like. Examples of salicylic acid esters include phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate. Among these exemplified ultraviolet absorbers, in particular, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4,4′-methoxybenzophenone, 2 (2′-hydroxy-3′-tert-butyl- 5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole is particularly preferred.

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

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

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

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

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

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

  Examples of the peeling accelerator include citric acid ethyl esters. Furthermore, infrared absorbers are described, for example, in JP-A No. 2001-194522.

  The timing for adding these additives may be added at any stage in the dope preparation process, but may be performed by adding a process for adding additives as the final preparation process in the dope preparation process. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, and these are conventionally known techniques.

  The glass transition point Tg of the cellulose acylate film of the present invention is preferably 70 to 180 ° C, more preferably 100 to 170 ° C, and more preferably 120 ° C to 160 ° C. The glass transition point Tg can be measured with a dynamic viscoelasticity measuring device (Biblon: DVA-225 (ITG Measurement Control Co., Ltd.)). The glass transition point can also be adjusted to the above range by appropriately selecting the type and amount of plasticizer. The cellulose acylate film of the present invention preferably has a glass transition point Tg within the above range from the viewpoint of process suitability for polarizing plate processing and liquid crystal display device assembly.

  Furthermore, regarding the additive, the Japan Society of Invention and Innovation Technical Bulletin No. 2001-1745 (issued March 15, 2001, Japan Society of Invention) p. Those described in detail after 16 can be used as appropriate.

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

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

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

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

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

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

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

The alkyl group preferably 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, hydroxy group, carboxy 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- A diethylaminoethyl group is included.
The alkenyl group preferably has 2 to 8 carbon atoms. A chain alkenyl group is preferable to a cyclic alkenyl group, and a linear alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group, and a 1-hexenyl group.
The alkynyl group preferably has 2 to 8 carbon atoms. A chain alkynyl group is preferable to a cyclic alkynyl group, and a linear alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include ethynyl group, 1-butynyl group and 1-hexynyl group.

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

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

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

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

  Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group (eg, methyl). Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (eg, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group) ), Sulfamoyl group, alkylsulfamoyl group (eg, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido group, alkylureido group (eg, N -Methylureido group, N, N-dimethylureido group, N, N, N'-trimethylureido group), alkyl group (eg, Methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl, isopropyl, s-butyl, t-amyl, cyclohexyl, cyclopentyl), alkenyl (eg, vinyl, allyl) Group, hexenyl group), alkynyl group (eg, ethynyl group, butynyl group), acyl group (eg, formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (eg, acetoxy group, butyryloxy group, Hexanoyloxy group, lauryloxy group), alkoxy group (eg, methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, heptyloxy group, octyloxy group), aryloxy group (eg, phenoxy group), Alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, Ropoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (eg, phenoxycarbonyl group), alkoxycarbonylamino group (eg, butoxycarbonylamino group, hexyloxycarbonylamino group) , Alkylthio groups (eg, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group), arylthio groups (eg, phenylthio group), alkylsulfonyl groups (eg, methylsulfonyl group, ethylsulfonyl group) , Propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group), amide group (eg, acetamido group, butyramide group, hexylamide group, Uriruamido group) and a non-aromatic Hajime Tamaki (e.g., morpholyl groups include pyrazinyl group).

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

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

The alkenylene group and alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably have a linear structure rather than a branched chain structure.
The number of carbon atoms of the alkenylene group and the alkynylene group is preferably 2 to 10, more preferably 2 to 8, further preferably 2 to 6, further preferably 2 to 4, and most preferably 2. (Vinylene or ethynylene).
The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.

In the molecular structure of the general formula (1), the angle formed by Ar ¹ and Ar ² across L ¹ is preferably 140 degrees or more.
As the rod-like compound, a compound represented by the following formula (2) is more preferable.
Formula ^{(2): Ar 1 -L 2} -X-L 3 -Ar 2
In the general formula (2), Ar ¹ and Ar ² are each independently an aromatic group. The definition and examples of the aromatic group are the same as those of Ar ¹ and Ar ^{2 in} the general formula (1).

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

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

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

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

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

General formula (3)

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

Two or more rod-shaped compounds having a maximum absorption wavelength (λmax) shorter than 250 nm in the ultraviolet absorption spectrum of the solution may be used in combination.
The rod-like compound can be synthesized by a method described in the literature. As literature, Mol. Cryst. Liq. Cryst. 53, 229 pages (1979), 89, 93 pages (1982), 145, 111 pages (1987), 170, 43 pages (1989), J. Am. Am. Chem. Soc. 113, p. 1349 (1991), p. 118, p. 5346 (1996), p. 92, p. 1582 (1970). Org. Chem. 40, 420 pages (1975), Tetrahedron, Vol. 48, No. 16, page 3437 (1992).

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

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

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

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

In order to obtain a cellulose acylate film having particles having a small secondary average particle diameter in the present invention, several methods are conceivable when preparing a fine particle dispersion. For example, a method of preparing a fine particle dispersion in which a solvent and fine particles are mixed with stirring in advance, adding this fine particle dispersion to a small amount of cellulose acylate solution separately prepared, stirring and dissolving, and further mixing with the main cellulose acylate dope solution There is. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are more difficult to reaggregate. In addition, after adding a small amount of cellulose ester to the solvent and dissolving with stirring, add the fine particles to this and disperse with a disperser to make this fine particle additive solution, and mix this fine particle additive solution with the dope solution using an inline mixer There is also a way to do it. The present invention is not limited to these methods, but the concentration of silicon dioxide when the silicon dioxide fine particles are mixed and dispersed with a solvent or the like is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and 15 to 20%. Mass% is most preferred. A higher dispersion concentration is preferable because the liquid turbidity with respect to the added amount is lowered, and haze and aggregates are improved. The addition amount of the matting agent in the final cellulose acylate dope solution is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and 0.08 to 0.16 g per 1 m ^2. Most preferred.

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

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

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

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

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

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

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

  The mixing ratio of the above three types of mixed solvents is 20 to 95% by mass for the first solvent, 2 to 60% by mass for the second solvent, and 2 to 30% by mass for the third solvent in the total amount of the mixed solvent. The first solvent is preferably 30 to 90% by mass, the second solvent is 3 to 50% by mass, and the third alcohol is preferably 3 to 25% by mass. . In particular, it is preferable that the first solvent is 30 to 90% by mass, the second solvent is 3 to 30% by mass, and the third solvent is alcohol and 3 to 15% by mass. The non-chlorine-based organic solvent used in the present invention described above is more specifically described in JIII Journal of Technical Disclosure No. 2001-1745 (issued March 15, 2001, Invention Association) p. 12-16. Preferred combinations of non-chlorine organic solvents of the present invention can include the following, but are not limited thereto.

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

Further, a cellulose acylate solution prepared by the following method can also be used.
A method of adding a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass), adding 2 parts by weight of butanol after filtration and concentration,
A method in which a cellulose acylate solution is prepared with methyl acetate / acetone / ethanol / butanol (84/10/4/2, parts by mass), and 4 parts by weight of butanol is added after filtration and concentration.
A method in which a cellulose acylate solution is prepared with methyl acetate / acetone / ethanol (84/10/6, parts by mass), and 5 parts by weight of butanol is added after filtration and concentration.
In addition to the non-chlorine organic solvent of the present invention, the dope used in the present invention may contain dichloromethane in an amount of 10% by mass or less of the total organic solvent amount of the present invention.

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

  Next, in this invention, it is preferable that the aggregate molecular weight of the cellulose acylate in the diluted solution which made the cellulose acylate solution 0.1-5 mass% with the organic solvent of the same composition is 150,000-15 million. More preferably, the associated molecular weight is 180,000 to 9 million. This associated molecular weight can be determined by a static light scattering method. In this case, it is preferable to dissolve so that the inertial square radius required at the same time is 10 to 200 nm. A more preferable inertial square radius is 20 to 200 nm. Furthermore, it is preferable to dissolve so that the second virial coefficient is −2 × 10 −4 to + 4 × 10 −4, and more preferably, the second virial coefficient is −2 × 10 −4 to + 2 × 10 −4. It is.

Here, the definition of the association molecular weight, the inertial square radius, and the second virial coefficient in the present invention will be described. These are measured using the static light scattering method according to the following method. Although the measurement is performed in a dilute region for the convenience of the apparatus, these measured values reflect the behavior of the dope in the high concentration region of the present invention.
First, cellulose acylate is dissolved in a solvent used for the dope to prepare 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass% solutions. In order to prevent moisture absorption, the cellulose acylate is dried at 120 ° C. for 2 hours and is measured at 25 ° C. and 10% RH. The dissolution method is carried out according to the method employed at the time of dope dissolution (room temperature dissolution method, cooling dissolution method, high temperature dissolution method). Subsequently, these solutions and the solvent are filtered through a 0.2 μm Teflon filter. Then, the static light scattering of the filtered solution is measured at an interval of 10 ° from 30 ° to 140 ° at 25 ° C. using a light scattering measuring device (DLS-700 manufactured by Otsuka Electronics Co., Ltd.). The obtained data is analyzed by the BERRY plot method. In addition, the refractive index required for this analysis uses the value of the solvent calculated | required with the Abbe refractive system, and the refractive index concentration gradient (dn / dc) uses the differential refractometer (Otsuka Electronics Co., Ltd. DRM-1021). Measure using the solvent and solution used for light scattering measurement.

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

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

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

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

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

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

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

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

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

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

[Stretching treatment]
In the cellulose acylate film of the present invention, the retardation can be adjusted by a stretching treatment. Furthermore, there is also a method of positively stretching in the width direction. -48271, and the like. This stretches the produced film in order to increase the in-plane retardation value of the cellulose acylate film.
The film is stretched at room temperature or under heating conditions. The heating temperature is preferably ± 20 ° C. sandwiching the glass transition temperature of the film. If the film is stretched at a temperature extremely lower than the glass transition temperature, it tends to break and cannot exhibit desired optical properties. In addition, if the film is stretched at a temperature extremely higher than the glass transition temperature, it cannot be fixed by the heat at the time of stretching, and the orientation of the optical properties is developed before the molecularly oriented film is stretched by heat. Becomes worse.
The stretching of the film may be uniaxial stretching (fixed width, free width) only in the longitudinal or lateral direction, or simultaneous or sequential biaxial stretching. Stretching is usually performed at 10 to 200%. The stretching is preferably 12 to 100%, particularly preferably 15 to 80%. The birefringence of the optical film is preferably such that the refractive index in the width direction is larger than the refractive index in the length direction. Therefore, it is preferable to stretch more in the width direction. In addition, the stretching process may be performed in the middle of the film forming process, or the raw film that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount (residual solvent amount / (residual solvent amount + solid content amount)) may be preferably 2 to 50%.

The film thickness of the cellulose acylate film of the present invention obtained after drying varies depending on the purpose of use and is usually preferably in the range of 5 to 500 μm, more preferably in the range of 20 to 300 μm, still more preferably in the range of 30 to 180 μm. Particularly preferably, it is in the range of 40 to 180 μm, particularly preferably 40 to 150 μm. Moreover, it is preferable that it is 40-110 micrometers for optical uses, especially for VA liquid crystal display devices.
Although the film thickness of the film is 110 to 180 μm, the drying load during casting film formation increases, but the size of the optical characteristics is proportional to the film thickness, so the desired optical characteristics can be increased by increasing the film thickness. Can be achieved. In addition, since the moisture permeability also decreases in inverse proportion to the film thickness, increasing the film thickness reduces the moisture permeability and makes it more difficult for water to pass through. This is advantageous in a polarizing plate durability test at 60 ° C. and 90% RH for 500 hours.
The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like so as to obtain a desired thickness. The width of the cellulose acylate film obtained as described above is preferably 0.5 to 3 m, more preferably 0.6 to 2.5 m, still more preferably 0.8 to 2.2 m. The length is preferably 100 to 10,000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, knurling is preferably applied to at least one end, the width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. This may be a single push or a double push.

[Optical properties of cellulose acylate film]
The optical properties of the cellulose acylate film of the present invention are as follows:
Formula (IX): Re (λ) = (nx−ny) × d
Formula (X): Rth (λ) = {(nx + ny) / 2−nz} × d
It is preferable that the Re retardation value and the Rth retardation value represented by the following formulas (XI) and (XII) respectively satisfy the following formulas (XI) and (XII) in order to widen the viewing angle of a liquid crystal display device, particularly a VA mode liquid crystal display device.
Formula (XI): 30 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
Formula (XII): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm
[In the formula, Re (λ) is a front retardation value (unit: nm) at a wavelength λnm, and Rth (λ) is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film. That's it. ]
More preferably, the Re letter value satisfies the following mathematical formula (XIII).
Formula (XIII): 40 nm ≦ Re ₍₅₉₀₎ ≦ 100 nm
The cellulose acylate film of the present invention is an optical biaxial film and preferably satisfies the following formula (XIV) because the viewing angle of the VA mode liquid crystal display device can be particularly widened.
Formula (XIV): 160 nm ≦ Rth ₍₅₉₀₎ ≦ 300 nm

In the cellulose acylate film of the present invention, Re ₍₅₉₀₎ and Rth _{(590) at} 25 ° C. and 60% RH preferably satisfy the following mathematical formulas (A) to (C).
Formula (A): 40 ≦ Re ₍₅₉₀₎ ≦ 145
Formula (B): Rth ₍₅₉₀₎ = a- _5.9 Re ₍₅₉₀₎
Formula (C): 500 ≦ a ≦ 670
[Wherein, Re ₍₅₉₀₎ is a front retardation value (unit: nm) at a wavelength of ₅₉₀ nm, and Rth ₍₅₉₀₎ is a retardation value (unit: nm) in the film thickness direction at a wavelength of 590 nm. Further, a is an adjustment factor (unit: nm) of optical characteristics. ]
a is an adjustment coefficient of Re and Rth, more preferably 520 ≦ a ≦ 650, and further preferably 540 ≦ a ≦ 640. The presence of a in the above range is preferable in terms of widening the viewing angle characteristics of the vertical alignment type liquid crystal display device.

In the cellulose acylate film of the present invention, Re ₍₆₃₀₎ and Rth _{(630) at} 25 ° C. and 60% RH preferably satisfy the following mathematical formulas (A ′) to (C ′).
Formula (A ′) 46 ≦ Re ₍₆₃₀₎ ≦ 150
Formula (B ′) Rth ₍₆₃₀₎ = a′−5.9Re ₍₆₃₀₎
Formula (C ′) 580 ≦ a ′ ≦ 670
[Wherein, Re ₍₆₃₀₎ is the front retardation value (unit: nm) at a wavelength of ₆₃₀ nm, and Rth ₍₆₃₀₎ is the retardation value (unit: nm) in the film thickness direction at a wavelength of 630 nm. Further, a ′ is an optical characteristic adjustment coefficient (unit: nm). ]
a ′ is an adjustment coefficient of Re and Rth, more preferably 590 ≦ a ′ ≦ 660, and further preferably 600 ≦ a ′ ≦ 650. The presence of a ′ in the above range is preferable in terms of widening the viewing angle characteristics of the vertical alignment type liquid crystal display device.

The cellulose acylate film of the invention, the Re ₍₅₉₀₎ value and the difference ΔRe (= Re10% RH-Re80 % RH) between the Re ₍₅₉₀₎ value at 25 ° C. 80% RH at 25 ° C. 10% RH, is 0 to 10 nm, the _{Rth (590)} value and a difference _{ΔRth (590) (= Rth10%} RH-Rth80% RH) and _{Rth (590)} value at 25 ° C. 80% RH at 25 ℃ 10% RH, 0~ The thickness of 30 nm is preferable in order to reduce the color change with time of the liquid crystal display device.

The film thickness distribution in the width direction of Re was sequentially sampled from the position of 2 cm (width direction) × 3 cm (width direction perpendicular) of the film in the width direction from the position of the film edge 5 cm, Ten points were collected at equal intervals. The film thickness of each test piece (2 cm × 3 cm) was measured for a total of nine points in the longitudinal and horizontal directions in the plane of the film, and was taken as the film thickness of the sample.
When the film thickness distribution R is defined as R (%) = (Rmax−Rmin) / Rave × 100 when the maximum value, minimum value, and average value of the film thickness in the width direction are Rmax, Rmin, and Rave, respectively. These are preferably adjusted to 0 to 8%, more preferably adjusted to 0 to 7.8%, and further preferably adjusted to 0 to 7.6%. Since Re and Rth are values proportional to the film thickness, the smaller the film thickness distribution in the width direction of the film thickness, the smaller the variation in Re ⁽⁵⁹⁰⁾ and Rth ₍₅₉₀₎ , which is preferable.
The distribution of Re ₍₅₉₀₎ and Rth ₍₅₉₀₎ is caused by the film thickness variation or due to stretching unevenness, drying unevenness, etc., but this Re distribution (variation) is 5% or less. The Rth distribution is preferably adjusted to 10% or less. More preferably, the Re distribution is 4.8% or less, the Rth distribution is 9.8% or less, more preferably the Re distribution is 4.6% or less, and the Rth distribution is 9.6% or less. It is preferable.
The film thickness distribution R, Re distribution, and Rth distribution described above are preferable because display unevenness is reduced when the film is used in a liquid crystal display device (particularly a VA liquid crystal display device).

In the present invention, the optical characteristics were measured by the following method. In addition, in the description of the claims and the specification, when there is no description regarding the temperature and humidity at the time of measurement, the measurement of the optical characteristics was performed at 25 ° C. and 60% RH.
Re (λ) was measured with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) by making light having a wavelength of λ nm incident in the normal direction of the film. Rth (λ) is Re (λ), a retardation value measured by making light of wavelength λnm incident from a direction inclined + 40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis, And retardation values measured in three directions, including retardation values measured by making light of wavelength λ nm incident from a direction inclined by −40 ° with respect to the normal direction of the film with the in-plane slow axis as the tilt axis. Based on this, an assumed average refractive index of 1.48 and a film thickness were input and calculated.

In the cellulose acylate film of the present invention, the color difference ΔE ^* ab before and after aging at 90 ° C. for 500 hours is preferably 0.8 or less, preferably 0.7 or less, The following is more preferable. The color difference between before and after aging at 140 ° C. for 24 hours is preferably 1.5 or less, more preferably 1.0 or less, and further preferably 0.5 or less. If the film is colored under environmentally forced conditions such as 90 ° C. for 500 hours or 140 ° C. for 24 hours, the optical compensation ability as a retardation film is lowered, which is not preferable in terms of appearance. The color difference was measured using UV3100 (manufactured by Shimadzu Corporation). The measurement was carried out by adjusting the film to 25 ° C. and 60% RH for 2 hours or more, and then measuring the color of the film before aging the thermo to obtain initial values (L0 ^* , a0 ^* , b0 ^* ). Thereafter, the film alone was left in an air thermostat for a predetermined time. After the elapse of a predetermined time, the film was taken out from the thermostatic bath, adjusted to 25 ° C. and 60% RH for 2 hours, then subjected to color measurement, and values after thermo-aging (L1 ^* , a1 ^* , b1 ^* ) were obtained. From these, the color difference ΔE ^* ab = ((L0 ^* −L1 ^* ) ² + (a0 ^* −a1 ^* ) ² + (b0 ^* −b1 ^* ) ² ) ^1/2 was obtained.

In the cellulose acylate film of the present invention, the equilibrium moisture content at 25 ° C. and 80% RH is preferably 5.0% or less, more preferably 4.0% or less, and 3.2% or less. It is more preferable to reduce the color change with time of the liquid crystal display device.
The moisture content is measured by measuring the cellulose acylate film sample 7 mm × 35 mm of the present invention by the Karl Fischer method using a moisture measuring device and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). . Calculated by dividing the amount of water (g) by the sample weight (g).
Further, the cellulose acylate film of the present invention has a water permeability of 60 ° C., 95% RH, 24 hr (film thickness 80 μm conversion) of 400 g / m ² · 24 hr or more and 1800 g / m ² · 24 hr or less. This is preferable for reducing the change in color of the display device over time.
If the film thickness of the cellulose acylate film is thick, the moisture permeability becomes small, and if the film thickness is thin, the moisture permeability becomes large. The measured moisture permeability is converted with a reference film thickness of 80 μm. The converted value of moisture permeability is calculated by “80 μm converted moisture permeability = actually measured moisture permeability × actually measured film thickness μm / 80 μm”.
The measurement method of moisture permeability is “Polymer Properties II” (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294: Measurement of vapor permeation (mass method, thermometer method, vapor pressure method, adsorption amount method) The method described in can be applied.

  The glass transition temperature is measured by adjusting the viscoelasticity measuring apparatus (Vibron: DVA-225) after conditioning the cellulose acylate film sample (unstretched) 5 mm × 30 mm of the present invention at 25 ° C. and 60% RH for 2 hours or more. Manufactured by IT Measurement Control Co., Ltd.), measured with a distance between grips of 20 mm, a heating rate of 2 ° C./min, a measuring temperature range of 30 ° C. to 200 ° C., and a frequency of 1 Hz, and the vertical axis is the logarithmic axis and the storage elastic modulus is When a linear axis is taken at a temperature (° C.), a straight line 1 is drawn in the solid region to draw a straight line 1 in the solid region, and the storage elastic modulus transitions from the solid region to the glass transition region. When the straight line 2 is drawn, the intersection of the straight line 1 and the straight line 2 is a temperature at which the storage elastic modulus suddenly decreases and the film starts to soften when the temperature rises. Transition temperature Tg ( Viscoelasticity) to.

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

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

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

[Polarizer]
Next, the polarizing plate of the present invention will be described.
The polarizing plate is usually composed of a polarizer and two transparent protective films disposed on both sides thereof. In the present invention, the cellulose acylate film of the present invention is used as at least one protective film. The other protective film may be the cellulose acylate film of the present invention or a normal cellulose acetate film. Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film. When the cellulose acylate film of the present invention is used as a polarizing plate protective film, the method for producing the polarizing plate is not particularly limited, and can be produced by a general method. For example, there is a method in which the obtained cellulose acylate film is treated with an alkali and bonded to both sides of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Examples of the adhesive used to bond the protective film-treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like. The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and a protective film may be bonded to one surface of the polarizing plate and a separate film may be bonded to the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

As shown in FIG. 3, the method of laminating the cellulose acylate film of the present invention to the polarizer is such that the transmission axis of the polarizer matches the slow axis of the cellulose acylate film of the present invention (TAC1 in the figure). It is preferable to bond together.
In addition, the polarizing plate produced under polarizing plate crossed Nicol, when the orthogonal accuracy between the slow axis of the cellulose acylate film of the present invention and the absorption axis of the polarizer (axis orthogonal to the transmission axis) is greater than 1 °, Polarization degree performance under a polarizing plate crossed Nicole decreases, light leakage occurs, and when combined with a liquid crystal cell, a sufficient black level and contrast cannot be obtained, so the main refractive index of the cellulose acylate film of the present invention The deviation between the direction of nx and the direction of the transmission axis of the polarizing plate is preferably within 1 °, preferably within 0.5 °.

Further, in the present invention, by laminating so that the direction in which the shrinkage rate of the polarizer is maximized and the direction in which the shrinkage rate of the optical cellulose acylate film is maximized are substantially parallel, Even after the compulsory test, the performance degradation of the liquid crystal display device can be reduced.
For example, in an iodine-based polarizer and a dye-based polarizer manufactured using a film such as the polyvinyl alcohol-based film, the direction in which the film constituting the polarizer is mainly stretched, and the optical cellulose acylate film It is preferable that the layers are bonded so that the direction in which they are mainly stretched is substantially orthogonal.

In the present invention, the single plate transmittance, parallel transmittance, and orthogonal transmittance of the polarizing plate were measured using UV3100PC (manufactured by Shimadzu Corporation). In the measurement, the measurement was performed in the range of 380 nm to 780 nm under the condition of 25 ° C. and 60% RH, and the average value of 10 measurements was used for each of the single plate, parallel and orthogonal transmittances. The polarizing plate durability test was performed as follows in two types of forms in which (1) only the polarizing plate and (2) the polarizing plate were bonded to glass via an adhesive. For the measurement of only the polarizing plate, two orthogonal and identical ones were prepared and measured so that the optical compensation film was sandwiched between the two polarizers. Two samples (approx. 5 cm × 5 cm) are prepared by attaching a polarizing plate on glass so that the optical compensation film is on the glass side. In the single plate transmittance measurement, the film side of this sample was set facing the light source. Two samples were measured respectively, and the average value was defined as the transmittance of the single plate. The preferable range of polarization performance is 40.0 ≦ TT ≦ 45.0, 30.0 ≦ PT ≦ 40.0, and CT ≦ 2.0 in the order of single plate transmittance, parallel transmittance, and orthogonal transmittance, respectively. More preferable range is 40.2 ≦ TT ≦ 44.8, 32.2 ≦ PT ≦ 39.5, CT ≦ 1.6, and further preferable range is 41.0 ≦ TT ≦ 44.6. 34 ≦ PT ≦ 39.1 and CT ≦ 1.3.
The degree of polarization P is calculated from these transmittances, and the greater the degree of polarization P, the less light leaks when the cross arrangement is made, indicating that the performance of the polarizing plate is higher. The degree of polarization P is preferably 95.0% or more, more preferably 96.0% or more, and further preferably 97.0% or more.

The polarizing plate of the present invention has T ₍₃₈₀₎ when the orthogonal transmittance at wavelength λ is T (λ _).
, T ₍₄₁₀₎ and T ₍₇₀₀₎ preferably satisfy at least one of the following formulas (e) to (g).
(E) T ₍₃₈₀₎ ≦ 2.0
(F) T ₍₄₁₀₎ ≦ 1.0
(G) T ₍₇₀₀₎ ≦ 0.5
More preferably, T ₍₃₈₀₎ ≤1.95, T ₍₄₁₀₎ ≤0.9, T ₍₇₀₀₎ ≤0.49, and even more preferably T ₍₃₈₀₎ ≤1.90, T ₍₄₁₀₎ ≤0. .8, T ₍₇₀₀₎ ≦ 0.48.
The polarizing plate of the present invention has an orthogonal single plate transmittance change ΔCT and a polarization degree change ΔP of at least the following formulas (j) and (k) when left at 60 ° C. and 95% RH for 500 hours. It is preferable to satisfy one or more.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
(However, the amount of change is the value obtained by subtracting the pre-test measurement value from the post-test measurement value)
More preferably, −5.8 ≦ ΔCT ≦ 5.8, −9.5 ≦ ΔP ≦ 0.0, and still more preferably, −5.6 ≦ ΔCT ≦ 5.6, −9.0 ≦ ΔP ≦ 0.0. It is.
The polarizing plate of the present invention has an orthogonal single plate transmittance change ΔCT and a polarization degree change ΔP of at least the following formulas (h) and (i) when left at 60 ° C. and 90% RH for 500 hours. It is preferable to satisfy one or more.
(H) −3.0 ≦ ΔCT ≦ 3.0
(I) −5.0 ≦ ΔP ≦ 0.0
In the polarizing plate of the present invention, at least one or more of the following formulas (l) and (m) has a change amount ΔCT and a change degree of polarization degree ΔP of the orthogonal single plate when left at 80 ° C. for 500 hours. It is preferable to satisfy.
(L) −3.0 ≦ ΔCT ≦ 3.0
(M) −2.0 ≦ ΔP ≦ 0.0
In the polarizing plate durability test, the amount of change is preferably smaller.

[surface treatment]
The cellulose acylate film of the present invention can achieve improved adhesion between the cellulose acylate film and each functional layer (for example, the undercoat layer and the back layer) by optionally performing a surface treatment. As the surface treatment, for example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs in a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Regarding these, the details are disclosed in the Invention Association Public Technical Bulletin No. 2001-1745 (issued March 15, 2001, Invention Association) p. 30-32. Note that, in the plasma treatment at atmospheric pressure which has been attracting attention in recent years, for example, irradiation energy of 20 to 500 Kgy is used under 10 to 1000 Kev, and more preferably irradiation energy of 20 to 300 Kgy is used under 30 to 500 Kev. Among these, an alkali saponification treatment is particularly preferable, and it is extremely effective as a surface treatment of a cellulose acylate film.

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

  In the polarizing plate of the present invention, it is preferable that at least one layer of a hard coat layer, an antiglare layer and an antireflection layer is provided on the surface of the protective film on the other side of the polarizing plate. That is, as shown in FIG. 4, it is preferable to provide a functional film such as an antireflection layer on the protective film (TAC2) disposed on the side opposite to the liquid crystal cell when the polarizing plate is used in a liquid crystal display device. It is preferable to provide at least one layer of a hard coat layer, an antiglare layer and an antireflection layer as the functional film. Each layer does not need to be provided as a separate layer. For example, the antireflection layer may function as an antireflection layer and an antiglare layer by providing the antireflection layer with a function as an antiglare layer.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The light scattering layer is made of an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above mat particles, in order to increase the refractive index of the layer. Thus, it is preferable that an inorganic filler having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less is contained.
Conversely, in order to increase the refractive index difference from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the layer low in the light scattering layer using the high refractive index mat particles. The preferred particle size is the same as that of the aforementioned inorganic filler.
Specific examples of the inorganic filler to be used in the light scattering _{layer, TiO 2, ZrO 2, Al} 2 O3, In 2 O3, ZnO, SnO 2, Sb 2 O 3, ITO and SiO ₂ and the like. TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index. The surface of the inorganic filler is preferably subjected to silane coupling treatment or titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the light scattering layer, more preferably 20 to 80%, and particularly preferably 30 to 75%.
In addition, since such a filler has a particle size sufficiently smaller than the wavelength of light, scattering does not occur, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

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

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

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

[High refractive index layer and medium refractive index layer]
The layer having a high refractive index of the antireflection layer is composed of a cured film containing at least an inorganic compound fine particle having a high refractive index having an average particle diameter of 100 nm or less and a matrix binder.
Examples of the high refractive index inorganic compound fine particles include inorganic compound fine particles having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include fine particles such as oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.
In order to obtain fine particles having an average particle size of 100 nm or less, the surface of the particles is treated with a surface treatment agent (for example, silane coupling agents, etc .: JP-A Nos. 1-295503, 11-153703, and 2000). No.-9908, an anionic compound or an organometallic coupling agent: Japanese Patent Laid-Open No. 2001-310432, etc., and a core-shell structure with high refractive index particles as a core (eg, Japanese Patent Laid-Open No. 2001-166104) ), Specific dispersants (for example, JP-A No. 11-153703, US Pat. No. 6,210,858B1, JP-A No. 2002-276069) and the like.
Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.
Further, a polyfunctional compound-containing composition containing at least two polymerizable groups of at least one of radically polymerizable and cationically polymerizable, an organometallic compound containing a hydrolyzable group, and a partial condensate-containing composition thereof At least one composition selected is preferred. For example, the composition as described in Unexamined-Japanese-Patent No. 2000-47004, 2001-315242, 2001-31871, 2001-296401 etc. is mentioned.
A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, it describes in Unexamined-Japanese-Patent No. 2001-293818.
The refractive index of the high refractive index layer is preferably 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70. The thickness is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.

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

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

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

[Hard coat layer]
The hard coat layer is provided on the surface of the protective film in order to impart physical strength to the protective film provided with the antireflection layer. In particular, it is preferably provided between the transparent support and the high refractive index layer. The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of the curable compound by at least one of light and heat. The curable functional group in the curable compound is preferably a photopolymerizable functional group. Also preferred are hydrolyzable functional group-containing organometallic compounds and organoalkoxysilyl compounds.
Specific examples of these compounds are the same as those exemplified for the high refractive index layer. Specific examples of the constituent composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO00 / 46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.

The hard coat layer can also serve as an antiglare layer containing particles having an average particle size of 0.2 to 10 μm and imparted with an antiglare function (antiglare function).
The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

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

[Antistatic layer]
In the case of providing an antistatic layer, it is preferable to impart conductivity with a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less. Although it is possible to give a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) by using a hygroscopic substance, a water-soluble inorganic salt, a certain surfactant, a cationic polymer, an anionic polymer, colloidal silica or the like, There is a problem that dependency is large, and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material. Some metal oxides are colored, but using such metal oxides as the conductive layer material is not preferable because the entire film is colored. Zn, Ti, Al, In, Si, Mg, Ba, Mo, W, or V can be given as the metal that forms the metal oxide without coloration, and a metal oxide mainly composed of this can be used. preferable. Specific examples include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ , V ₂ O ₅ , and complex oxides thereof. ZnO, TiO ₂ and SnO ₂ are preferred. Examples of containing different atoms include, for example, additives such as Al and In for ZnO, addition of Sb, Nb and halogen elements for SnO ₂ , and Nb and TA for TiO ₂ . Addition is effective. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a material in which the above metal oxide is attached to other crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. The volume resistance value and the surface resistance value are different physical properties and cannot be simply compared. However, in order to ensure conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance, The prevention layer should just have a surface resistance value of 10 ⁻¹⁰ (Ω / □) or less, more preferably 10 ⁻⁸ (Ω / □) or less. The surface resistance value of the antistatic layer is a value obtained when the antistatic layer is the outermost layer, and can be measured in the middle of forming the antistatic layer.

[Liquid Crystal Display]
The liquid crystal display device of the present invention is a liquid crystal display device (first embodiment) using either the above-described cellulose acylate film of the present invention or the polarizing plate of the present invention, and the polarizing plate of the present invention above or below the cell. An OCB or VA mode liquid crystal display device using two sheets (second embodiment) and a VA mode liquid crystal display device (third embodiment) using one polarizing plate of the present invention on the backlight side.
That is, the cellulose acylate film of the present invention is advantageously used as an optical compensation sheet. Moreover, the polarizing plate using the cellulose acylate film of the present invention is advantageously used in a liquid crystal display device. The cellulose acylate film of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-ferroelectric Liquid)
Various display modes have been proposed, such as Crystal), OCB (Optically Compensatory Bend), STN (Supper Twisted Nematic), VA (Vertically Aligned), and HAN (Hybrid Aligned Nematic). Among these, it can use preferably for VA mode or OCB mode.

In a VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625) (2) Liquid crystal cell (SID97, Digest of tech. Papers (Preliminary Proceed) 28 (1997) 845 in which the VA mode is made into a multi-domain (MVA mode) for widening the viewing angle ), (3) Liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japanese Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).
As shown in FIG. 5, the VA mode liquid crystal display device comprises a liquid crystal cell (VA mode cell) and two polarizing plates (polarizing plates comprising TAC1, polarizer and TAC2) disposed on both sides thereof. Is mentioned. The liquid crystal cell carries liquid crystal between two electrode substrates, although not particularly shown.

In one aspect of the transmissive liquid crystal display device of the present invention, the cellulose acylate film of the present invention is used as an optical compensation sheet, and one sheet is disposed between the liquid crystal cell and one polarizing plate, or Two sheets are arranged between both polarizing plates.
In another aspect of the transmissive liquid crystal display device of the present invention, the cellulose acylate film of the present invention is used as a protective film for a polarizing plate disposed between a liquid crystal cell and a polarizer. The above cellulose acylate film may be used only for the protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, or both polarizing plates (between the liquid crystal cell and the polarizer). The cellulose acylate film may be used for the two protective films. For the lamination to the liquid crystal cell, the cellulose acylate film (TAC1) of the present invention is preferably on the VA cell side. When the above cellulose acylate film is used only for the protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, this is the upper polarizing plate (observation side) and the lower polarizing plate (backlight side). Either side can be used and there is no functional problem. However, when used as an upper polarizing plate, it is necessary to provide a functional film on the observation side (upper side) and the production yield may be lowered. It is considered an embodiment.

And what formed both the light source side and observer side of FIG. 5 with the polarizing plate of this invention is the liquid crystal display device of a 2nd form, and what formed only the light source side with the polarizing plate of this invention is 3rd. It is a liquid crystal display device of a form.
The protective film (TAC2) shown in FIG. 5 may be a normal cellulose acylate film, and is preferably thinner than the cellulose acylate film of the present invention. For example, 40-80 μm is preferable, and examples include, but are not limited to, commercially available KC4UX2M (40 μm manufactured by Konica Capto), KC5UX (60 μm manufactured by Konica Capto), TD80 (80 μm manufactured by Fuji Photo Film), and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to an Example.

[Example 1: Production of cellulose acylate film]
(Cellulose acylate)
Cellulose acylates having different types of acyl groups and different degrees of substitution described in Table 1 were prepared. This was carried out by adding sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) as a catalyst, adding carboxylic acid as a raw material for the acyl substituent, and carrying out an acylation reaction at 40 ° C. At this time, the kind and substitution degree of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid. Moreover, it age | cure | ripened at 40 degreeC after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone. In the table, CAP is an abbreviation for cellulose acetate propionate (a cellulose ester derivative in which an acyl group is composed of an acetate group and a propionyl group), and CTA is a cellulose triacetate (a cellulose in which an acyl group is composed only of an acetate group). Ester derivative). CAB means an abbreviation for cellulose acetate butyrate.

(1) Cellulose acylate Cellulose acylates having different degrees of acyl substitution described in Table 1 were prepared. In this, sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) was added as a catalyst, and carboxylic acid was added to perform an acylation reaction at 40 ° C. Thereafter, the total substitution degree and the 6-position substitution degree were adjusted by adjusting the amount of sulfuric acid catalyst, the amount of water, and the aging time. The aging temperature was 40 ° C. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.
(2) Dope Preparation <1-1> Cellulose Acylate Solution The following composition is put into a mixing tank, stirred to dissolve each component, further heated to 90 ° C. for about 10 minutes, It filtered with the sintered metal filter with an average hole diameter of 10 micrometers.
―――――――――――――――――――――――――――――――――
Cellulose acylate solution ――――――――――――――――――――――――――――――――――
Cellulose acylate listed in Table 1 100.0 parts by mass Triphenyl phosphate 8.0 parts by mass Biphenyl diphenyl phosphate 4.0 parts by mass Methylene chloride 403.0 parts by mass Methanol 60.2 parts by mass ――――――――――――――――――――――――――

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

<1-3> Retardation developer solution Next, the following composition containing the cellulose acylate solution prepared by the above method was put into a mixing tank and dissolved by stirring while heating to prepare a retardation developer solution. .
―――――――――――――――――――――――――――――――――
Retardation developer solution A
―――――――――――――――――――――――――――――――――
Retardation developer A 20.0 parts by mass Methylene chloride 58.3 parts by mass Methanol 8.7 parts by mass Cellulose acylate solution 12.8 parts by mass ――――――――――――――――― ―――――――――――――――
100 parts by mass of the cellulose acylate solution, 1.35 parts by mass of the matting agent dispersion, and the retardation developer solution A were mixed in the proportions shown in Tables 1 to 3 to prepare a dope for film formation. The ratio of addition of the retardation enhancer is shown in Table 1 in terms of parts by mass when the cellulose acylate amount is 100 parts by mass.

Retardation expression agent A

<1-4> Retardation developer solution B
Furthermore, the following composition containing the cellulose acylate solution prepared by the above method was put into a mixing tank and dissolved by stirring while heating to prepare a retardation developer solution B. ―――――――――――――――――――――――――――――――――
Retardation developer solution B
―――――――――――――――――――――――――――――――――
Retardation developer A 8.0 parts by weight Retardation developer B 12.0 parts by weight Methylene chloride 58.3 parts by weight Methanol 8.7 parts by weight Cellulose acylate solution 12.8 parts by weight ―――――――――――――――――――――――――
100 parts by mass of the cellulose acylate solution, 1.35 parts by mass of the matting agent dispersion, and the retardation developer solution B were mixed at a ratio shown in Table 1 to prepare a dope for film formation. The ratio of addition of the retardation enhancer is shown in Table 1 in terms of parts by mass when the cellulose acylate amount is 100 parts by mass.

Retardation expression agent B

(Dissolution (preparation of dope))
The cellulose acylate, plasticizer and retardation developing agent described in Table 1 were added to the following mixed solvent, dichloromethane / methanol (87/13 parts by mass) with stirring so that the mass concentration of cotton was 15% by mass. Then, the mixture was heated and stirred to dissolve. At the same time, a matting agent (silicon dioxide (primary particle diameter 20 nm), Mohs hardness of about 7) 0.05 parts by mass is added to 100 parts by mass of cellulose acylate, and the dope is stirred while heating. Prepared.

(Casting, stretching)
The above dope was cast using a band casting machine. The drying conditions on the band were dried under the conditions shown in Table 2, and then the film peeled off from the band with a residual solvent amount of 60 to 100 wt% DB was supplied to the tenter zone at an air supply temperature of 140 ° C. (exhaust temperature was 90 ° C. to 125 ° C. The cellulose acylate film (thickness: 92 μm) was produced by stretching in the width direction under the conditions shown in Table 2. The cast film thickness was adjusted so that the film thickness after stretching was 92 μm. For the purpose of producing a film having the composition shown in Table 1 and judging its suitability for production, at least 24 rolls having a roll width of 1460 mm and a roll length of 2600 mm were produced under the above conditions, and a long run test was performed. All the examples shown in the table were suitable for long run.

About the produced cellulose acylate film (optical compensation sheet), the Re retardation value and the Rth retardation value at a wavelength of 590 nm were measured at 25 ° C. and 60% RH using an automatic birefringence meter (KOBRA 21ADH: Oji Scientific Instruments). The results are shown in Table 1.
The film was conditioned at 25 ° C. 10% RH and 25 ° C. 80% RH for 2 hours or more, and then measured in that environment. Difference in retardation of cellulose acylate film between 80% RH and 10% RH at this time ΔRe, ΔRth (ΔRe = Re (10% RH) −Re (80% RH), ΔRth = Rth (10% RH) − Rth (80% RH)), the stretched CTA in the table had ΔRe of 4 to 9 nm and ΔRth of 15 to 30. The stretched CAP had ΔRe of 10 nm or less and ΔRth of 28 nm or less. CAB had ΔRe of 8 nm or less and ΔRth of 13 nm or less.

[Example 2: Polarizing plate]
<2-1-1>
(Preparation of polarizing plate-1)
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film.
The cellulose acylate films (samples 101 to 117, samples 001 to 006, comparative samples 201 and 202) prepared in Example 1 were attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. The saponification treatment was performed under the following conditions.
A 1.5N aqueous sodium hydroxide solution was prepared and kept at 55 ° C. A 0.01 N dilute sulfuric acid aqueous solution was prepared and kept at 35 ° C. The produced cellulose acylate film was immersed in the aqueous sodium hydroxide solution for 2 minutes, and then immersed in water to sufficiently wash away the aqueous sodium hydroxide solution. Subsequently, after being immersed in the above-mentioned dilute sulfuric acid aqueous solution for 1 minute, it was immersed in water to sufficiently wash away the dilute sulfuric acid aqueous solution. Finally, the sample was thoroughly dried at 120 ° C.
A commercially available cellulose triacylate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd .: equivalent to the functional film TAC2 in FIG. 4, TAC2-1 or 2-2 in FIG. 5) is subjected to saponification treatment, and polyvinyl alcohol type Using an adhesive, it was attached to the opposite side of the polarizer and dried at 70 ° C. for 10 minutes or more.
The transmission axis of the polarizer and the slow axis of the cellulose acylate film produced in Example 1 were arranged so as to be parallel (FIG. 3).
It arrange | positioned so that the transmission axis of a polarizer and the slow axis of a commercially available cellulose triacylate film might orthogonally cross.
In this way, polarizing plates A101 to A117, polarizing plates A001 to A006, comparative polarizing plates A201 and A202 (optical compensation film integrated polarizing plate having no functional film in FIG. 4) were produced.

<2-2-1>
(Preparation of coating solution for light scattering layer)
50 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (PETA, Nippon Kayaku Co., Ltd.) was diluted with 38.5 g of toluene. Further, 2 g of a polymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added and mixed and stirred. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.51.
Further, a 30% toluene dispersion of crosslinked polystyrene particles having an average particle size of 3.5 μm (refractive index: 1.60, SX-350, manufactured by Soken Chemical Co., Ltd.) dispersed in this solution for 20 minutes at 10,000 rpm with a Polytron disperser. Add 13.3 g of 30% toluene dispersion of 1.7 g and crosslinked acrylic-styrene particles having an average particle size of 3.5 μm (refractive index 1.55, manufactured by Soken Chemical Co., Ltd.), and finally, fluorine-based surface modification 0.75 g of agent (FP-1) and 10 g of silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to obtain a finished solution.
The liquid mixture was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the light scattering layer.

<2-2-2>
(Preparation of coating solution for low refractive index layer)
First, sol solution a was prepared as follows. A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. After adding 30 parts of ion-exchanged water and reacting at 60 ° C. for 4 hours, it was cooled to room temperature to obtain a sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.
Thermally crosslinkable fluorine-containing polymer having a refractive index of 1.42 (JN-7228, solid content concentration 6%, manufactured by JSR Corporation) 13 g, silica sol (silica, MEK-ST particle size difference, average particle size 45 nm, solid content 30% concentration, manufactured by Nissan Chemical Co., Ltd.) 1.3 g, 0.6 g of the above sol solution a, 5 g of methyl ethyl ketone, and 0.6 g of cyclohexano were added. After stirring, the solution was filtered through a polypropylene filter having a pore size of 1 μm. A coating solution for the refractive index layer was prepared.

<2-2-3>
(Preparation of transparent protective film 01 with light scattering layer)
An 80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) is unwound in a roll form, and the above functional layer (light scattering layer) coating solution has a line number of 180 lines / inch, Using a gravure pattern with a depth of 40 μm and a microgravure roll with a diameter of 50 mm and a doctor blade, it was applied under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 30 m / min, dried at 60 ° C. for 150 seconds, and further purged with nitrogen Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) at 160 W / cm, the coating layer is cured by irradiating ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 250 mJ / cm ² , and a thickness of 6 μm A layer was formed and wound up.
The triacetyl cellulose film coated with the functional layer (light scattering layer) is unwound again, and the prepared coating liquid for the low refractive index layer is gravure with a line number of 180 lines / inch and a depth of 40 μm on the light scattering layer side. Using a micro gravure roll with a diameter of 50 mm and a doctor blade having a pattern, it is applied under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 15 m / min, dried at 120 ° C. for 150 seconds, and further dried at 140 ° C. for 8 minutes. Then, using a 240 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under a nitrogen purge, ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ² were irradiated, and a low refraction of 100 nm thickness was achieved. An index layer was formed and wound up (corresponding to the functional film TAC2 in FIG. 4 or TAC2-1 in FIG. 5).

<2-3-1>
(Preparation of polarizing plate-2)
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film.
The prepared transparent protective film 01 with a light scattering layer is subjected to the same saponification treatment as described in <2-1-1>, and a side without a functional film and one side of a polarizer are pasted using a polyvinyl alcohol-based adhesive. I attached.
The cellulose acylate film produced in Example 1 (samples 101 to 117, samples 001 to 006, comparative samples 201 and 202: corresponding to TAC1 in FIG. 3) was subjected to the same saponification treatment, and a polyvinyl alcohol-based adhesive was used. Then, it was affixed to the opposite side of the polarizer and dried at 70 ° C. for 10 minutes or more (the configuration in FIG. 4 was completed).
The transmission axis of the polarizer and the slow axis of the cellulose acylate film produced in Example 1 were arranged so as to be parallel (FIG. 3).
The transmission axis of the polarizer and the slow axis of the transparent protective film 01 with the light scattering layer were arranged so as to be orthogonal to each other. In this way, polarizing plates (B101 to B117, polarizing plates B001 to B006, comparative polarizing plates B201 and B202: functional film and optical compensation film integrated polarizing plate (FIG. 4)) were prepared.
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film. The transparent protective film 01 with a light-scattering layer prepared in <2-2-3> and a triacetylcellulose film (TAC-TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm not coated with a functional layer. The saponification process was performed in the same manner as described above, and was bonded to the polarizer in the same manner as described above using a polyvinyl alcohol-based adhesive. In this way, a polarizing plate (B0: plain polarizing plate with a light scattering layer) was prepared.
Using a spectrophotometer (manufactured by JASCO Corporation), in the wavelength region of 380 to 780 nm, the spectral reflectance at an incident angle of 5 ° is measured from the functional film side, and the integrating sphere average reflectance of 450 to 650 nm is obtained. When determined, it was 2.3%.
Using a spectrophotometer (UV3100PC), measure the single plate transmittance TT, parallel transmittance PT, orthogonal transmittance CT of the polarizing plate of 380 nm to 780 nm in combination with the optical compensation film inside the polarizer, When an average value of 400 to 700 nm was determined for the sample of the present invention, TT was 42.7, PT was 38, and CT was 0.8. Further, in the polarizing plate durability test at 60 ° C. and 95% RH for 500 hours, both fall within the range of −0.1 ≦ ΔCT ≦ 0.2 and −2.0 ≦ ΔP ≦ 0, and at −60 ° C. and 90% RH, −0.05 ≦ ΔCT ≦ 0.15 and −1.5 ≦ ΔP ≦ 0.

<2-4-1>
(Preparation of coating solution for hard coat layer)
750.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Nippon Kayaku Co., Ltd.), 270.0 parts by mass of poly (glycidyl methacrylate) having a mass average molecular weight of 3000, 730.0 g of methyl ethyl ketone, 500.0 g of cyclohexanone and light A polymerization initiator (Irgacure 184, manufactured by Nippon Ciba-Geigy Co., Ltd.) 50.0 g was added and stirred. The solution was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a hard coat layer.

<2-4-2>
(Preparation of titanium dioxide fine particle dispersion)
As the titanium dioxide fine particles, titanium dioxide fine particles (MPT-129, manufactured by Ishihara Sangyo Co., Ltd.) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide were used.
The following dispersant (38.6 g) and cyclohexanone (704.3 g) were added to 257.1 g of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

Dispersant

<2-4-3>
(Preparation of coating solution for medium refractive index layer)
To 88.9 g of the above titanium dioxide dispersion, 58.4 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA), 3.1 g of a photopolymerization initiator (Irgacure 907), a photosensitizer (Kayacure DETX) 1.1 g of Nippon Kayaku Co., Ltd.), 482.4 g of methyl ethyl ketone and 1869.8 g of cyclohexanone were added and stirred. After sufficiently stirring, the solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a medium refractive index layer.

<2-4-4>
(Preparation of coating solution for high refractive index layer)
To 56.8 g of the above titanium dioxide dispersion, 47.9 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), photopolymerization initiator (Irgacure 907, Nippon Ciba Geigy ( Co., Ltd.) 4.0 g, photosensitizer (Kayacure-DETX, Nippon Kayaku Co., Ltd.) 1.3 g, methyl ethyl ketone 455.8 g, and cyclohexanone 1427.8 g were added and stirred. Pore diameter 0.
The solution was filtered through a 4 μm polypropylene filter to prepare a coating solution for a high refractive index layer.

<2-4-5>
(Preparation of coating solution for low refractive index layer)
The following copolymer was dissolved in methyl isobutyl ketone so as to have a concentration of 7% by mass, and a terminal methacrylate group-containing silicone resin X-22-164C (manufactured by Shin-Etsu Chemical Co., Ltd.) was 3% based on the solid content, light Radical generator Irgacure 907 (trade name) was added in an amount of 5% by mass based on the solid content to prepare a coating solution for a low refractive index layer.

Copolymer

<2-4-6>
(Preparation of transparent protective film 02 with antireflection layer)
A hard coat layer coating solution was applied onto a triacetyl cellulose film (TD-80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm using a gravure coater. After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^{2. The} coating layer was cured by irradiating ultraviolet rays with an irradiation amount of 300 mJ / cm ² to form a hard coat layer having a thickness of 8 μm.
On the hard coat layer, a medium refractive index layer coating solution, a high refractive index layer coating solution, and a low refractive index layer coating solution were successively applied using a gravure coater having three coating stations.

The intermediate refractive index layer was dried at 100 ° C. for 2 minutes, and the ultraviolet curing condition was 180 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 1.0% by volume or less. The irradiance was 400 mW / cm ² and the irradiation amount was 400 mJ / cm ² . The medium refractive index layer after curing had a refractive index of 1.630 and a film thickness of 67 nm.

The drying conditions of the high refractive index layer and the low refractive index layer are both 90 ° C., 1 minute, 100 ° C., 1 minute, and the ultraviolet curing condition is nitrogen so that the oxygen concentration is 1.0 volume% or less. While purging, a 240 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) was used to obtain an irradiation amount of 600 mW / cm ² and an irradiation amount of 600 mJ / cm ² .
The cured high refractive index layer had a refractive index of 1.905 and a film thickness of 107 nm, and the low refractive index layer had a refractive index of 1.440 and a film thickness of 85 nm. Thus, the transparent protective film 02 with an antireflection layer was produced (corresponding to the functional film TAC2 in FIG. 4 or TAC2-1 in FIG. 5).

<2-5-1>
(Preparation of polarizing plate-3)
Polarizing plates (C101 to C117, C001 to C006, comparative polarizing plate C201) in the same manner as in <2-3-1> except that the transparent protective film 02 with an antireflection layer was used instead of the transparent protective film with a light scattering layer 01. , C202: A functional film and an optical compensation film integrated polarizing plate (FIG. 4)) were produced. Moreover, it consists of the 80-micrometer-thick triacetyl cellulose film (TAC-TD80U, Fuji Photo Film Co., Ltd. product) which does not apply | coat the transparent protective film 02 with an antireflection layer, a polarizer, and a functional layer by the same method. A polarizing plate (C0) was produced.
Using a spectrophotometer (manufactured by JASCO Corporation), in the wavelength region of 380 to 780 nm, the spectral reflectance at an incident angle of 5 ° is measured from the functional film side, and the integrating sphere average reflectance of 450 to 650 nm is obtained. When determined, it was 0.4%.

[Example 3]
(Mounting on the panel)
[Example 3-1]
(Mounting on VA panel) (Single sheet type)
The liquid crystal display device of FIG. 5 was produced. That is, from the observation direction (top), the upper polarizing plate (TAC2-1 (with / without functional film), polarizer, TAC1-1), VA mode liquid crystal cell, lower polarizing plate (TAC1-2, polarizer, TAC2) -2) were laminated, and a backlight light source was further arranged. In the following example, a commercially available polarizing plate (HLC2-5618) is used for the upper polarizing plate, and a polarizing plate integrated with an optical compensation film is used for the lower polarizing plate. But there is no problem functionally. However, as an integrated polarizing plate, it is often used as a lower polarizing plate (if it is used as an upper polarizing plate, it is necessary to provide a functional film on the observation side (upper side) and the production yield may be lowered. Therefore, it is considered to be a more preferable embodiment.

<Production of liquid crystal cell>
The liquid crystal cell has a cell gap between substrates of 3.6 μm, and a liquid crystal material having negative dielectric anisotropy (“MLC6608”, manufactured by Merck & Co., Inc.) is dropped and sealed between the substrates. Prepared by forming a layer. The retardation of the liquid crystal layer (that is, the product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn) was set to 300 nm. The liquid crystal material was aligned so as to be vertically aligned.

  For the upper polarizing plate (observer side) of the liquid crystal display device (FIG. 5) using the vertical alignment type liquid crystal cell, a commercially available super high contrast product (for example, HLC2-5618 manufactured by Sanlitz Co., Ltd.) is used. It was. Polarizing plate (A104 to A113) prepared in <2-1-1> of Example 2 using the optical compensation sheet prepared in Example 1 (samples 104 to 113) for the lower polarizing plate (backlight side) The cellulose acylate film prepared in Example 1 (corresponding to TAC1-2 in FIG. 5) was placed on the liquid crystal cell side. The upper polarizing plate and the lower polarizing plate were attached to the liquid crystal cell via an adhesive. The crossed Nicols were arranged so that the transmission axis of the upper polarizing plate was in the vertical direction and the transmission axis of the lower polarizing plate was in the left-right direction. A liquid crystal display device was prepared using a polarizing plate to be used which was previously conditioned and stored for 2 hours under a temperature and humidity condition of 25 ° C. and 60% RH.

Here, a commercial product is used for the upper polarizing plate and the integrated polarizing plate of the present invention is used for the lower polarizing plate. As a result of observing the produced liquid crystal display device, the front direction and the viewing angle direction are also neutral. Black display was realized. In addition, using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM), the viewing angle (contrast ratio is 10 or more and there is no black-side gradation inversion) in eight stages from black display (L1) to white display (L8). Range).
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM), the viewing angle (contrast ratio is 10 or more and there is no gradation inversion on the black side) in 8 steps from black display (L1) to white display (L8). ) Was measured.

Next, a measuring instrument (EZ-Contrast160D, manufactured by ELDIM) measuring the color at the time of black display with an azimuth angle of 45 ° based on the horizontal direction of the liquid crystal display screen and a polar angle of 60 ° based on the normal direction of the screen surface Was used as an initial value. Next, this panel was aged at 60 ° C. and 90% RH for 120 hours, left in a room at 25 ° C. and 60% RH for 24 hours, and the color when displaying black was measured again.
Table 4 below shows the measurement of viewing angle and color change. All of the examples had a wide viewing angle and little color change. The amount of light leakage around the panel after the environmental forced test was very small.

[Example 3-2]
<2-1 of Example 2 in which the optical compensation sheet prepared in Example 1 (samples 104 to 113) was used for the lower polarizing plate of the liquid crystal display device (FIG. 5) using the vertical alignment type liquid crystal cell described above. The polarizing plate (B0) prepared in <2-3-1> of Example 2 was attached to the upper polarizing plate via the pressure-sensitive adhesive (A104 to A113). The crossed nicols were arranged so that the transmission axis of the polarizing plate on the observer side was in the vertical direction and the transmission axis of the polarizing plate on the backlight side was in the horizontal direction. At this time, the air-conditioning was performed so that the temperature of the workplace was 20 to 25 ° C. and the humidity was 50 to 70% RH. A liquid crystal display device was prepared by using a polarizing plate that had been preconditioned for 2 hours under temperature and humidity conditions of 25 ° C. and 60% RH.
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, as in Example 3-1, measurement of viewing angle and color change, and aging for 120 hours at 60 ° C. and 90% RH, left in a room at 25 ° C. and 60% RH for 24 hours, and again during black display The color was measured and the results are shown in Table 4.
All of the examples had a wide viewing angle and little color change. The amount of light leakage around the panel after the environmental forced test was very small.

[Example 3-3]
<2-1 of Example 2 in which the optical compensation sheet prepared in Example 1 (samples 104 to 113) was used for the lower polarizing plate of the liquid crystal display device (FIG. 5) using the vertical alignment type liquid crystal cell described above. The polarizing plate (C0-113) prepared in <2-5-1> of Example 2 was attached to the upper polarizing plate via an adhesive. The crossed nicols were arranged so that the transmission axis of the polarizing plate on the observer side was in the vertical direction and the transmission axis of the polarizing plate on the backlight side was in the horizontal direction. At this time, the workplace was air-conditioned so that the temperature of the workplace was 20 to 25 ° C. and the humidity was 50 to 70% RH. A liquid crystal display device was prepared using a polarizing plate to be used that had been stored in a moisture-proof and moisture-proof bag for 2 hours under the temperature and humidity conditions of 25 ° C. and 60% RH.
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, as in Example 3-1, measurement of viewing angle and color change, and aging for 120 hours at 60 ° C. and 90% RH, left in a room at 25 ° C. and 60% RH for 24 hours, and again during black display The color was measured and the results are shown in Table 4.
All of the examples had a wide viewing angle and little color change. The amount of light leakage around the panel after the environmental forced test was very small.

[Example 3-4]
The same operation as in Example 3-3 was performed except that the lower polarizing plate of Example 3-3 was changed to A001 to A004.
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, as in Example 3-1, measurement of viewing angle and color change, and aging for 120 hours at 60 ° C. and 90% RH, left in a room at 25 ° C. and 60% RH for 24 hours, and again during black display The color was measured and the results are shown in Table 4.
All of the examples had a wide viewing angle and little color change. In addition, the amount of light leakage around the panel after the environmental forced test was small.

[Example 3-5]
The same operation as in Example 3-3 was performed except that the lower polarizing plate of Example 3-3 was changed to A114 to A117.
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, as in Example 3-1, measurement of viewing angle and color change, and aging for 120 hours at 60 ° C. and 90% RH, left in a room at 25 ° C. and 60% RH for 24 hours, and again during black display The color was measured and the results are shown in Table 4.
All of the present examples had a wide viewing angle, and the color change was relatively small. In addition, the amount of light leakage around the panel after the environmental forced test was small.

[Comparative Example 3-1]
The same operation as in Example 3-3 was performed except that the lower polarizing plate of Example 3-3 was A201 and A202.
As a result of observing the manufactured liquid crystal display device, a neutral black display was realized in the front direction and the viewing angle direction. In addition, as in Example 3-1, measurement of viewing angle and color change, and aging for 120 hours at 60 ° C. and 90% RH, left in a room at 25 ° C. and 60% RH for 24 hours, and again during black display The color was measured and the results are shown in Table 4.
In all of the comparative examples, the viewing angle was large and the color change was relatively large. In addition, the amount of light leakage at the periphery of the panel after the environmental forced test was large, and a decrease in display quality was observed.

In addition, the sensory evaluation of the light leakage of the peripheral part after an environmental forced test was performed as follows.
○: Light leakage at the periphery is very small.
(Triangle | delta): The light leak of a peripheral part is small.
×: Large light leakage at the periphery

According to Table 4 above, the panel using the comparative sample has good initial performance, but due to the change in black color after the environmental forcing test and the remarkable increase in the amount of light leakage observed in the peripheral area of the panel, the environmental forcing test. As a result, the display quality deteriorated.
On the other hand, it can be seen that the sample of the present invention has a small amount of light leakage in the peripheral portion after the environmental forcing test, and generally good display performance is obtained even after the environmental forcing test.

Solution casting process diagram used in the practice of the present invention Schematic plan view of a width direction stretching device (tenter) used in the practice of the present invention It is a schematic diagram which shows the preferable bonding method of the cellulose acylate film at the time of manufacture of the polarizing plate of this invention. It is sectional drawing which shows typically an example of the cross-sectional structure of the polarizing plate of this invention. It is sectional drawing which shows typically an example of the cross-section of the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Web 2 Casting port 3 Casting surface 4 Peeling part 5 Width direction extending | stretching apparatus 6 Hot air 7 Width direction extending | stretching apparatus inlet 8 Width direction extending | stretching apparatus exit 9 Drying part 10 Winder 11 Position which hold | maintains both ends of a web with a tenter clip 12 Position for substantially starting stretching 13 Position for substantially finishing stretching process 14 Position for substantially finishing relaxation process 15 Position for releasing retention by tenter clip

Claims (27)

As a polymer component constituting the film, cellulose acylate which is a fatty acid ester of cellulose obtained by substituting the hydroxyl group of cellulose with at least one group out of an acyl group having 3 or more carbon atoms and an acetyl group is included. This is a cellulose acylate film, and the shrinkage rate (unit:%) in the casting (MD) direction and the casting width (TD) direction of the film when aged for 120 hours in an environment of 60 ° C. and 90% RH is S. An optical cellulose acylate film characterized in that S (MD) and S (TD) satisfy the following formula (1) when (MD) and S (TD).
Formula (1): S (MD) ≦ S (TD) The optical cellulose acylate film according to claim 1, wherein the S (MD) and S (TD) satisfy the following mathematical formulas (2) to (4).
Formula (2): S (TD) = S (MD) × 5/8 + C
Formula (3): −0.4 ≦ S (MD) ≦ 0.2
Formula (4): −0.125 ≦ C ≦ 0.125
[In the formula, C is a heat shrinkage adjustment coefficient (unit:%). ] Production starting from film raw material as a starting material, including a casting process, a film peeling process, a conveying process, a process of holding both ends of a web with a tenter clip, a stretching process, a relaxing process, and a process of releasing the holding by a tenter clip A cellulose acylate film produced by the method, wherein the distance from the position where the film is peeled off to the position where the tenter clip is released is set to L0, and stretching starts substantially from the position where the film is peeled off. When the distance to the position is L1, and the distance from the position where the film is peeled off to the position where the stretching process is substantially finished is L2, the following formulas (5) to (7) are set between L0, L1, and L2. The cellulose acylate film for optical use according to claim 2, wherein the cellulose acylate film is produced so as to satisfy the relationship of
Formula (5): 0.20 ≦ L1 / L0 ≦ 0.80
Formula (6): 0.50 ≦ L2 / L0 ≦ 0.95
Formula (7): L1 ≦ L2   4. The film is produced under such conditions that the amount of change in the volatile content based on the dry amount of the film between the position at which stretching is substantially started and the position at which the relaxation process is substantially completed is 3 to 90%. The cellulose acylate film for optical use according to 1. In the cellulose acylate, the substitution degree A of the acetyl group substituted with the hydroxyl group of cellulose and the substitution degree B of the acyl group having 3 or more carbon atoms satisfy the following formula (I), and in the stretching step: The optical cellulose acylate film according to any one of claims 1 to 4, which is substantially stretched by 10% or more in the casting direction and / or in the casting width direction.
Formula (I): 2.0 ≦ A + B ≦ 3.0 When the substitution degree of the 2-position hydroxyl group of the cellulose acylate with an acyl group is DS2, the substitution degree of the 3-position hydroxyl group with an acyl group is DS3, and the substitution degree of the 6-position hydroxyl group with an acyl group is DS6. The optical cellulose acylate film according to claim 1, wherein the following formulas (VI-a) and (VI-b) are satisfied.
Formula (VI-a): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI-b): DS6 / (DS2 + DS3 + DS6) ≧ 0.315   The optical cellulose acylate film according to claim 1, comprising a butanoyl group as an acyl group.   The optical cellulose acylate film according to any one of claims 1 to 7, comprising a propionyl group as an acyl group and having a substitution degree B of 0.6 or more. The optical retardation according to any one of claims 1 to 8, wherein the front retardation Re (λ) and retardation Rth (λ) in the thickness direction of the film satisfy the following formulas (XI) and (XII): Cellulose acylate film.
Formula (XI): 30 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
Formula (XII): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm The optical cellulose acylate film according to claim 9, wherein Re ₍₅₉₀₎ and Rth ₍₅₉₀₎ satisfy the following formulas (XIII) and (XIV).
Formula (XIII): 40 nm ≦ Re ₍₅₉₀₎ ≦ 100 nm
Formula (XIV): 160 nm ≦ Rth ₍₅₉₀₎ ≦ 300 nm   The optical cellulose acylate film according to claim 1, comprising at least one retardation developer composed of a rod-like or discotic compound.   The optical cellulose acylate film according to claim 1, comprising at least one of a plasticizer, an ultraviolet absorber, and a peeling accelerator.   The optical cellulose acylate film according to claim 1, wherein the film has a thickness of 40 to 180 μm. 25 the difference between ℃ and Re ₍₅₉₀₎ value at 10% RH and Re ₍₅₉₀₎ value at _{25 ℃ 80% RH ΔRe (Re} (590) 10% RH-Re (590) RH 80%) is, in 0~10nm There, the _{Rth (590)} value and the difference between the _{Rth (590)} value at _{25 ℃ 80% RH ΔRth (590} ) (Rth (590) 10% RH-Rth (590) RH 80%) at 25 ° C. 10% RH It is 0-30 nm, The cellulose acylate film for optics in any one of Claims 1-13 characterized by the above-mentioned.   The optical cellulose acylate film according to claim 1, which is stretched by a uniaxial stretching method, a simultaneous biaxial stretching method, or a sequential biaxial stretching method. The optical cellulose acylate film according to claim 1, wherein Re ₍₅₉₀₎ and Rth _{(590) at} 25 ° C. and 60% RH satisfy the following formulas (A) to (C).
Formula (A): 40 ≦ Re ₍₅₉₀₎ ≦ 145
Formula (B): Rth ₍₅₉₀₎ = a- _5.9 Re ₍₅₉₀₎
Formula (C): 500 ≦ a ≦ 670
[Wherein, Re ₍₅₉₀₎ is a front retardation value (unit: nm) at a wavelength of ₅₉₀ nm, and Rth ₍₅₉₀₎ is a retardation value (unit: nm) in the film thickness direction at a wavelength of 590 nm. Further, a is an adjustment factor (unit: nm) of optical characteristics. ]   Film thickness distribution R calculated by R (%) = (Rmax−Rmin) / Rave × 100 where the maximum value, minimum value, and average value of the film thickness in the width direction are Rmax, Rmin, and Rave, respectively. Is adjusted to 0 to 8%, The cellulose acylate film according to any one of claims 1 to 16. The optical cellulose acylate film according to claim 1, wherein a distribution of Re ₍₅₉₀₎ is adjusted to 5% or less. The optical cellulose acylate film according to claim 1, wherein a distribution of Rth ₍₅₉₀₎ is adjusted to 10% or less.   A polarizing plate, wherein at least one of the two protective films of the polarizer comprises the optical cellulose acylate film according to claim 1. 21. The single plate transmittance TT, parallel transmittance PT, orthogonal transmittance CT, and polarization degree P at 25 ° C. and 60% RH satisfy at least one of the following formulas (a) to (d). The polarizing plate as described in.
(A) 40.0 ≦ TT ≦ 45.0
(B) 30.0 ≦ PT ≦ 40.0
(C) CT ≦ 2.0
(D) 95.0 ≦ P T ₍₃₈₀₎ , T ₍₄₁₀₎ , T ₍₇₀₀₎ satisfy at least one of the following formulas (e) to (g), where T (λ) is the orthogonal transmittance at the wavelength λ. The polarizing plate according to claim 20 or 21.
(E) T ₍₃₈₀₎ ≦ 2.0
(F) T ₍₄₁₀₎ ≦ 1.0
(G) T ₍₇₀₀₎ ≦ 0.5 The change amount ΔCT of the orthogonal single plate transmittance and the change amount ΔP of polarization degree satisfy at least one of the following formulas (j) and (k) when left at 60 ° C. and 95% RH for 500 hours. The polarizing plate according to any one of claims 20 to 22.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
(However, the amount of change is the value obtained by subtracting the measured value before the test from the measured value after the test.)   The polarizing plate according to claim 20, wherein at least one of a hard coat layer, an antiglare layer, and an antireflection layer is provided on the surface of one protective film of the polarizer. .   A liquid crystal display device comprising at least one of the optical cellulose acylate film according to claim 1 and the polarizing plate according to any one of claims 20 to 24.   25. An OCB or VA mode liquid crystal display device, wherein any one of the polarizing plates according to claim 20 is used above and below a liquid crystal cell.   A VA mode liquid crystal display device using any one of the polarizing plates according to claim 20 on the backlight side.

Images