JP2006323329A - Cellulose acylate film, polarizing plate, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose acylate film which excels in property of exhibiting an in-plane retardation and a retardation in a thickness direction and ensures less thickness variation in a breadth direction, a polarizing plate using the film, a liquid crystal display on which bright spot foreign matter and planar unevenness are inconspicuous and which ensures less change in viewing angle characteristics, and a liquid crystal display which ensures less change in optical characteristics and less change in color due to an environmental humidity change. <P>SOLUTION: The cellulose acrylate film for optics has a front retardation Re(λ) (unit: nm) of 46≤Re(630)≤200, a retardation in a film thickness direction Rth(λ) (unit: nm) of 70≤Rth(630)≤350 and a thickness variation between every 10 mm in a breadth direction of ≤0.6 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

Liquid crystal display devices are widely used in personal computer and portable device monitors and television applications because of their various advantages such as low voltage and low power consumption, as well as miniaturization and thinning. In such a liquid crystal display device, various modes have been proposed depending on the alignment state of the liquid crystal 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, Japanese Patent No. 2587398 discloses a technique for applying a discotic liquid crystal on a triacetyl cellulose film, aligning it, and applying the fixed optical compensation sheet 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, IPS (In-Plane Switching) mode, OCB (Optically Compensatory Bend) mode, VA (Vertically
Liquid crystal display devices different from the TN mode, such as the (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.

The cellulose acylate film is characterized by high optical isotropy (low retardation value) compared to other polymer films. Therefore, it is common to use a cellulose acetate film for an application requiring optical isotropy, for example, a polarizing plate. Patent Document 1 discloses a method for producing a cellulose acetate film with little insoluble matter and high transparency by defining the relationship between the viscosity average degree of polymerization of cellulose acetate and the viscosity of a dope obtained by dissolving this in a solvent. Further, in Patent Document 2, in order to eliminate a planar failure called a die line, there is a preferable relationship among the thickness d of the cellulose acetate film, the solid content concentration y (%) of the film forming solution of the cellulose acetate film, and the solution viscosity ρ. It is disclosed.
On the other hand, the optical compensation sheet (retardation film) of the liquid crystal display device is required to have optical anisotropy (high retardation value). In particular, an optical compensation sheet for VA requires in-plane retardation (Re) of 30 to 200 nm and thickness direction retardation (Rth) of 70 to 400 nm. Therefore, it is common to use a synthetic polymer film having a high retardation value such as a polycarbonate film or a polysulfone film as the optical compensation sheet.
As described above, in the technical field of optical materials, when a polymer film requires optical anisotropy (high retardation value), a synthetic polymer film is used and optical isotropy (low retardation value) is used. It was a general principle to use cellulose acetate film when required.

Patent Document 3 discloses a cellulose acetate film having a high retardation value that can be used for applications requiring optical anisotropy, overcoming the conventional general principle. In this document, in order to achieve a high retardation value with cellulose triacetate, an aromatic compound having at least two aromatic rings, particularly a compound having a 1,3,5-triazine ring, is added and subjected to stretching treatment.
Cellulose triacetate is generally a polymer material that is difficult to stretch, and it is known that it is difficult to increase the birefringence. To achieve a high retardation value. Since this film can also serve as a protective film for the polarizing plate, there is an advantage that an inexpensive and thin liquid crystal display device can be provided.

The method described in the above patent document is effective in that an inexpensive and thin liquid crystal display device can be obtained. However, in recent years, a higher retardation value has been required, and it has become necessary to increase the amount of addition of the retardation developer or to increase the draw ratio. Streaky irregularities extending in the casting direction due to the thickness variation in the width direction, which are called vertical stripes, become apparent, and bright spot foreign matter and luminance and color irregularities that become apparent only when assembled in a liquid crystal display device are problems. I came. In particular, a cellulose acylate film used for a large-sized liquid crystal television has an optical axis shift of a maximum of −1 degree to +1 degree depending on the position in the width direction and the length direction.
Further, when the cellulose acylate film is assembled on a polarizing plate or when two polarizing plates are bonded to a liquid crystal cell, the optical axis is likely to be displaced by about 1 degree at maximum. When the deviation between the optical axis of the polarizing film and the optical axis of the cellulose acylate film or the deviation of the optical axis between the two polarizing plates becomes large, light leakage in black display becomes significant. The greater the deviation of the optical axis, the more blurred the film is even when the film thickness varies at narrow intervals in the width direction of the cellulose acylate film, even if the absolute value is small. Brightness unevenness comes to be visually recognized. There has been a demand for a solution to such surface unevenness. Also, the larger the screen, the less the generation of bright spot foreign matter, the lower the yield of polarizing plates and liquid crystal display devices and the higher the production cost. Therefore, improvement in this aspect has also been demanded.
JP 2000-131524 A JP 2001-129838 A European Patent Application No. 91656

An object of the present invention is to provide a cellulose acylate film which is excellent in in-plane and thickness direction retardation and has little thickness variation in the width direction, and a polarizing plate using the film.
A second object of the present invention is to provide a liquid crystal display device in which bright spot foreign matter and surface unevenness are not conspicuous and change in viewing angle characteristics is small.
A third object of the present invention is to provide a cellulose acylate film that hardly changes in optical characteristics due to changes in environmental humidity, and a liquid crystal display device that has little change in color due to changes in environmental humidity.

These objects have been achieved by the following means.
1. The front retardation Re (λ) is 46 ≦ Re (630) ≦ 200, the retardation Rth (λ) in the film thickness direction is 70 ≦ Rth (630) ≦ 350, and any 10 mm in the width direction is 10 mm. An optical cellulose acylate film having a thickness variation of 0.6 μm or less.
[Where Re (λ) is the front retardation (Re) value (unit: nm) at wavelength λnm, and Rth (λ) is the thickness direction retardation (Rth) value (unit: nm) at wavelength λnm. . ]
2. The cellulose acylate film for optical use according to 1 above, obtained by casting a dope having a viscosity at 2.33 ° C. of 10 Pas to 70 Pas.
3. 3. The cellulose acylate film for optical use according to 1 or 2 above, wherein the degree of polymerization of the cellulose acylate is from 265 to 380.
4). 4. The cellulose acylate film for optical use according to any one of 1 to 3 above, wherein the cellulose acylate has a bulk specific gravity of 0.30 or more and 0.80 or less.
5. A film made of cellulose acylate obtained by substituting a hydroxyl group of a glucose unit constituting cellulose with an acyl group having 2 or more carbon atoms, wherein the substitution degree of the hydroxyl group at the 2-position of the glucose unit with an acyl group is DS2 The above-mentioned formulas (I) and (II) are satisfied, where DS3 represents the substitution degree of the hydroxyl group at the 3-position with DS3, and DS6 represents the substitution degree with the acyl group of the hydroxyl group at 6-position. 4. The cellulose acylate film for optical use according to any one of 4 above.
(I): 2.0 ≦ DS2 + DS3 + DS6 ≦ 2.85
(II): DS6 / (DS2 + DS3 + DS6) ≧ 0.315

6). 6. The optical cellulose acylate film as described in any one of 1 to 5 above, which contains at least one retardation developer composed of a rod-like or discotic compound.
7). The optical cellulose acylate film as described in any one of 1 to 6 above, which contains at least one of a plasticizer, an ultraviolet absorber, and a peeling accelerator.
8). 8. The cellulose acylate film for optical use according to any one of 1 to 7 above, wherein the film has a thickness of 40 to 180 [mu] m.
9. Content of the additive added to this cellulose acylate is 10 to 30 mass% of film mass, The optical cellulose acylate film in any one of said 1-8 characterized by the above-mentioned.
The difference ΔRe (= Re 10% RH−Re 80% RH) between Re (Re 10% RH) value at 10.25 ° C. and 10% RH and Re (Re 80% RH) value at 25 ° C. and 80% RH is 12 nm or less, The difference ΔRth (= Rth 10% RH−Rth 80% RH) between Rth (Rth 10% RH) value at 25 ° C. and 10% RH and Rth (Rth 80% RH) value at 25 ° C. and 80% RH is 32 nm or less. The cellulose acylate film for optics according to any one of 1 to 9 above.
11. The cellulose acylate film for optical use according to any one of 1 to 10 above, wherein the equilibrium water content at 11.25 ° C. and 80% RH is 3.4% or less.
12. The moisture permeability (when converted to a film thickness of 80 μm) when placed at 95% RH for 24 hours at 60 ° C. is 400 g / m ² · 24 hr or more and 2300 g / m ² · 24 hr or less Cellulose acylate film for optical use.
13. The cellulose acylate film for optical use according to any one of 1 to 12 above, wherein a mass change is 0 to 5% when left to stand at 80 ° C. and 90% RH for 48 hours.
14. Dimensional change when left for 24 hours under conditions of 60 ° C and 90% RH and dimensional change when left for 24 hours under conditions of 90 ° C and 3% RH are both ± 2% 14. The optical cellulose acylate film as described in any one of 1 to 13 above.

15. Glass transition temperature Tg is 80-180 degreeC, The cellulose acylate film for optics of said 1-14 characterized by the above-mentioned.
16. The optical cellulose acylate film as described in any one of 1 to 15 above, wherein the elastic modulus is from 1500 to 5000 MPa.
17. 17. The optical cellulose acylate film as described in any one of 1 to 16 above, which has a photoelastic coefficient of 50 × 10 ⁻¹³ cm ² / dyn (5 × 10 ⁻¹¹ Pa-1) or less.
18. The optical cellulose acylate film according to any one of 1 to 17 above, wherein the haze is 0.01 to 2%.
19. The cellulose acylate film for optical use according to any one of 1 to 18 above, which has silicon dioxide fine particles having a secondary average particle size of 0.2 to 1.5 μm.
Re (630) and Rth (630) measured at 20.25 ° C. and 60% RH environmental humidity satisfy the following formulas (A) to (C): Cellulose acylate film.
(A): 46 ≦ Re (630) ≦ 100
(B): Rth (630) = a−5.9Re (630)
(C): 520 ≦ a ≦ 600
Any one of 1 to 20 above, wherein the following relations (D) and (E) hold between the Re value and the Rth value measured by changing the wavelength at 21.25 ° C. and 60% RH environmental humidity: An optical cellulose acylate film according to claim 1.
(D): 0.90 ≦ Re (450) / Re (550) ≦ 1.10 and 0.90 ≦ Re (650) / Re (550) ≦ 1.10.
(E): 0.90 ≦ Rth (450) / Rth (550) ≦ 1.25 and 0.90 ≦ Rth (650) / Rth (550) ≦ 1.10.
22. The optical cellulose acylate film according to any one of claims 1 to 21, wherein the number of bright spot foreign matters having a major axis of 20 µm or more is 20 or less.

23. 23. A polarizing plate comprising at least one optical cellulose acylate film as described in any one of 1 to 22 above as a protective film for a polarizer.
24. The single plate transmittance TT (%), parallel transmittance PT (%), orthogonal transmittance CT (%) and polarization degree P measured under the conditions of 25 ° C. and 60% RH of the polarizing plate are the following formulas (a) to ( 24. The polarizing plate as described in 23 above, which satisfies at least one of d).
(A) 40.0 ≦ TT ≦ 45.0
(B) 30.0 ≦ PT ≦ 40.0
(C) CT ≦ 2.0
(D) 95.0 ≦ P
25. When the orthogonal transmittance at wavelength λ is CT (λ) (%), CT (380) (%), CT (410) (%), and CT (700) (%) are represented by the following formulas (e) to ( 25. The polarizing plate as described in 23 or 24 above, which satisfies at least one of g).
(E) CT (380) ≦ 2.0
(F) CT (410) ≦ 0.1
(G) CT (700) ≦ 0.5
The amount of change ΔCT (%) in the orthogonal single plate transmittance and the amount of change in polarization degree ΔP when left at 26.60 ° C. and 90% RH for 500 hours satisfy at least one of the following formulas (h) and (i): 26. The polarizing plate as described in any one of 23 to 25, which is satisfied.
(H) −3.0 ≦ ΔCT ≦ 3.0
(I) −5.0 ≦ ΔP ≦ 0.0
(Here, the amount of change indicates the value obtained by subtracting the measured value before the test from the measured value after the test.)
27. The change amount ΔCT of the orthogonal single plate transmittance and the polarization degree change amount ΔP satisfying at least one of the following formulas (j) and (k) when left to stand at 60 ° C. and 95% RH for 500 hours. 27. The polarizing plate as described in any one of 23 to 26 above.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
28. The above-mentioned, wherein the orthogonal single plate transmittance change ΔCT and polarization degree change ΔP when left at 28 ° C. for 500 hours satisfy at least one of the following formulas (l) and (m): The polarizing plate in any one of 23-27.
(L) −3.0 ≦ ΔCT ≦ 3.0
(M) −2.0 ≦ ΔP ≦ 0.0
29. 29. The polarized light according to any one of the above 23 to 28, wherein 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 disposed on the opposite side of the polarizing plate from the liquid crystal cell. Board.
30. The polarizing plate according to any one of the above 23 to 29, wherein the polarizing plate is packaged in a moisture-proof bag, and the humidity in the packaged state is 43% RH to 70% RH at 25 ° C. .
31. The package is packaged in a moisture-proof bag, and the humidity in the packaged package is a difference of 15% RH or less with respect to the humidity when the polarizing plate is bonded to the liquid crystal panel. The polarizing plate in any one of 23-30.

32. 32. An OCB mode liquid crystal display device comprising at least one of the optical cellulose acylate film according to any one of 1 to 21 or the polarizing plate according to any one of 23 to 31.
33. A VA mode liquid crystal display device using at least one of the optical cellulose acylate film according to any one of 1 to 22 or the polarizing plate according to any one of 23 to 31.
34. The VA according to 33, wherein only one of the optical cellulose acylate film according to any one of 1 to 22 or the polarizing plate according to any one of 23 to 31 is used. Mode liquid crystal display.
35. 33 or 33, wherein one of the optical cellulose acylate film according to any one of 1 to 22 and the polarizing plate according to any one of 23 to 31 is used on a backlight side. 34. The VA mode liquid crystal display device according to 34.

The cellulose acylate film of the present invention and a polarizing plate using the same have little variation in thickness in the width direction, little surface unevenness, excellent in-plane and thickness direction retardation, and retardation due to environmental humidity. There is little fluctuation of the value.
In addition, the liquid crystal display device of the present invention has little luminance unevenness, particularly vertical stripe-like luminance unevenness, little color variation and unevenness, and little change in viewing angle characteristics.

Hereinafter, the present invention will be described in detail.
(Cellulose acylate)
First, the cellulose acylate in which the present invention is preferably used will be described in detail. 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 an acyl group having 2 or more carbon atoms. The degree of acyl substitution means the ratio in which the hydroxyl group of cellulose is esterified at each of the 2-position, 3-position and 6-position (100% esterification has a substitution degree of 1).
The total acyl substitution degree, that is, DS2 + DS3 + DS6 is preferably 2.00 to 2.85, more preferably 2.22 to 2.82, and particularly preferably 2.40 to 2.80. Further, D6S / (DS2 + DS3 + DS6) is preferably 0.315 or more, particularly preferably 0.320 or more. Here, DS2 is the degree of substitution of the hydroxyl group at the 2-position of the glucose unit with an acyl group (hereinafter also referred to as “degree of acyl substitution at the 2-position”), and DS3 is the degree of substitution of the hydroxyl group at the 3-position with an acyl group (hereinafter, referred to as “acyl group”). DS6 is the substitution degree of the hydroxyl group at the 6-position with an acyl group (hereinafter also referred to as “acyl substitution degree at the 6-position”).

  Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more types of acyl groups are used, one of them is preferably an acetyl group. DSA + DSB where DSA is the total substitution degree of hydroxyl groups at the 2nd, 3rd and 6th positions with an acetyl group and DSB is the total substitution degree with an acyl group other than the acetyl group at the 2nd, 3rd and 6th hydroxyl groups. The value of is more preferably 2.2 to 2.85, and particularly preferably 2.40 to 2.80. The DSB is 1.70 or less, particularly 1.0 or less. Further, 28% or more of DSB is a substituent at the 6-position hydroxyl group, more preferably 30% or more is a substituent at the 6-position hydroxyl group, more preferably 31% or more, and particularly 32% or more is a 6-position hydroxyl group. It is also preferable that it is a substituent. Further, a cellulose acylate film having a DSA + DSB value of 6-position of cellulose acylate of 0.75 or more, more preferably 0.80 or more, and particularly 0.85 or more is preferable. Cellulose acylate having such an acylate group substitution property is excellent in solubility in a wide range of solvents, and a solution with less insoluble matter can be obtained. Furthermore, it becomes possible to produce a solution having a low viscosity and good filterability. As a result, the cellulose acylate film of the present invention has less foreign matter, and in particular, when incorporated in a liquid crystal display device to display black, it is possible to reduce so-called bright spot foreign matter that shines due to light leakage. .

  The acyl group having 3 or more carbon atoms of the cellulose acylate used in the present invention may be an aliphatic acyl group or an arylacyl group, and is not particularly limited. The cellulose acylate used in the present invention is, for example, cellulose alkylcarbonyl ester, alkenylcarbonyl ester, aromatic carbonyl ester, aromatic alkylcarbonyl ester or the like, and each may further have a substituted group. Preferred examples of the acyl group include propionyl, butanoyl, keptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, Examples thereof include benzoyl, naphthylcarbonyl, cinnamoyl and the like. Among these, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a t-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and a propionyl group and a butanoyl group are particularly preferable. is there.

(Method for synthesizing cellulose acylate)
The basic principle of the cellulose acylate synthesis method is described in Mita et al., “Wood Chemistry”, Kyoritsu Shuppan, 1968, pages 180-190. 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 acylation 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 keeping it at 35 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain a desired acyl substitution degree 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 into the cellulose acylate solution) to coagulate and separate the cellulose acylate, and the cellulose acylate is obtained by washing and stabilizing treatment.

  The cellulose acylate film of the present invention is preferably composed of a cellulose acylate in which the polymer component constituting the film substantially has the above definition. “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 particles are preferably used as a raw material for film production. 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 bulk specific gravity (apparent density) of the particles thus produced is preferably 0.3 to 0.8 kg / L. If the bulk specific gravity is small, bridging is likely to occur when charging from the silo to the dissolution tank. Conversely, if the bulk specific gravity is large, the solubility is poor. Therefore, a more preferable bulk specific gravity is 0.4 to 0.6. The particle diameter and bulk specific gravity are adjusted by adjusting the stirring speed and aggregation speed when agglomerating and precipitating. If the cellulose acylate concentration at the time of coagulation sedimentation is low, the bulk specific gravity becomes small. Conversely, if the cellulose acylate concentration is high, the bulk specific gravity becomes large.

The degree of polymerization of the cellulose acylate that can be used in the present invention is from 250 to 550, and the preferred degree of polymerization is from 265 to 380, particularly preferably from 280 to 360. The viscosity average degree of polymerization can be measured by Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pages 105-120, 1962). Further details are described in JP-A-9-95538. The viscosity average degree of polymerization is determined from the intrinsic viscosity [η] of cellulose acylate measured with an Ostwald viscometer by the following formula.
Viscosity average degree of polymerization DP = [η] / Km
In the formula, [η] is the intrinsic viscosity of cellulose acylate, and Km is a constant of 6 × 10 ⁻⁴ .

  The molecular weight distribution Mw / Mn (Mw is the weight average molecular weight, Mn is the number average molecular weight) of the cellulose acylate can be measured by gel permeation chromatography. In the present invention, the viscosity of the cellulose acylate solution is adjusted to a preferred value, but the viscosity of the cellulose acylate solution can also be adjusted to a preferred value by adjusting the molecular weight distribution of the cellulose acylate. In this respect, the specific value of Mw / Mn is preferably from 1.8 to 4.0, and more preferably from 2.1 to 3.5.

  The degree of polymerization and molecular weight distribution of cellulose acylate can be adjusted by the reaction temperature, reaction time, catalyst amount, etc. in the acetylation reaction. For example, when the amount of sulfuric acid catalyst is increased, the degree of polymerization tends to decrease. Therefore, the amount of the sulfuric acid catalyst is preferably adjusted to 0.5 to 20 parts by mass, more preferably 3 to 15 parts by mass with respect to 100 parts by mass of cellulose. When the amount of the sulfuric acid catalyst is in the above range, a cellulose acylate that is preferable also in terms of molecular weight distribution can be synthesized.

  The degree of polymerization of cellulose acylate and the molecular weight distribution can also be adjusted by the temperature at the time of saponification aging at the stage of neutralization and saponification aging, the amount of residual sulfuric acid, the neutralization rate and the amount of water. For example, when the amount of water in the reaction solution is kept low and saponification takes place over time, the depolymerization reaction proceeds simultaneously with the saponification reaction, so the degree of polymerization decreases.

  Furthermore, the degree of polymerization and the molecular weight distribution can be adjusted by removing low molecular weight components. For example, the low molecular weight component can be removed by washing cellulose acylate with a suitable organic solvent.

  The cellulose acylate used in the present invention preferably has a moisture content of 2% by mass or less, more preferably 1% by mass or less, and particularly a cellulose acylate having a moisture content of 0.7% by mass or less. is there. In general, cellulose acylate contains water and is known to be 2.5 to 5% by mass. In order to obtain the moisture content of the cellulose acylate in the present invention, it is necessary to dry, and the method is not particularly limited as long as the desired moisture content is obtained.

  These cellulose acylates of the present invention are described in detail on pages 7 to 12 in the raw material cotton and the synthesis method in the Japan Society for Invention and Innovation Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Japan Society for Invention). It is described in.

(Additive)
In the cellulose acylate solution according to the present invention, various additives (for example, plasticizers, ultraviolet inhibitors, deterioration inhibitors, retardation (optical anisotropy) modifiers, fine particles, Peeling accelerators, infrared absorbers, etc.) can be added and they can be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, mixing of UV absorbing materials at 20 ° C. or lower and 20 ° C. or higher, and similarly mixing of a plasticizer is described in, for example, JP-A-2001-151901. Examples of the peeling accelerator include citric acid ethyl esters. Furthermore, infrared absorbing dyes are described, for example, in JP-A No. 2001-194522. Moreover, the addition time may be added at any stage in the dope preparation process, but may be performed by adding an additive to the final preparation process of the dope preparation process. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is formed in a multilayer, the kind and addition amount of the additive of each layer may differ. Examples thereof are described in Japanese Patent Application Laid-Open No. 2001-151902 and the like, but these are conventionally known techniques. It is preferable to adjust the glass transition temperature Tg of the cellulose acylate film to 80 to 180 ° C. and the elastic modulus measured with a tensile tester to 1500 to 3000 MPa, depending on the selection of the types and addition amounts of these additives.
Further, for these details, materials described in detail on page 16 and after in the Invention Association Public Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Invention Association) are preferably used.

(Plasticizer)
The film of the present invention preferably contains a plasticizer. Although it does not specifically limit as a plasticizer which can be used, Triphosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. In acid ester systems, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, etc., in glycolic acid ester systems, triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl Less cellulose acylate such as glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate Specific preferred to singly or in combination one. Two or more plasticizers may be used in combination as required.

(Retardation expression agent)
In the present invention, in order to express the retardation value, a compound having at least two aromatic rings can be preferably used as the retardation enhancer. The retardation developer is preferably used in the range of 0.05 to 20 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, with respect to 100 parts by mass of the polymer. It is more preferable to use in the range of 5 to 5 parts by mass, and most preferable to use in the range of 0.5 to 2 parts by mass. Two or more retardation developing agents may be used in combination.
The retardation developer preferably has a maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

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, a benzene ring, a condensed benzene ring, and biphenyls are preferable. In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, compounds disclosed in JP-A No. 2001-166144 are preferably used.

The number of carbon atoms of the aromatic ring in the retardation enhancer is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and more preferably 2 to 6. Most preferred.
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-diethylaminoethyl groups. It is.
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 acetamide.
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 is preferably 300 to 800.

  In the present invention, a rod-shaped compound having a linear molecular structure can be preferably used in addition to a compound using a 1,3,5-triazine ring. 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 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 halogen atom (F, Cl, Br, I), hydroxyl, carboxyl, cyano, amino, alkylamino group (eg, methylamino, ethylamino) , Butylamino, dimethylamino groups), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (eg, N-methylcarbamoyl, N-ethylcarbamoyl, N, N-dimethylcarbamoyl groups), sulfamoyl group, Alkylsulfamoyl groups (eg, N-methylsulfamoyl, N-ethylsulfamoyl, N, N-dimethylsulfamoyl groups), ureido groups, alkylureido groups (eg, N-methylureido, N , N-dimethylureido, N, N, N′-trimethylureido groups), alkyl groups (eg, methyl, ether) Til, propyl, butyl, pentyl, heptyl, octyl, isopropyl, sec-butyl, t-amyl, cyclohexyl, cyclopentyl groups), alkenyl groups (eg, vinyl, allyl, hexenyl groups), alkynyl groups (eg, Ethynyl group, butynyl group), acyl group (eg, formyl, acetyl, butyryl, hexanoyl, lauryl groups), acyloxy group (eg, acetoxy, butyryloxy, hexanoyloxy, lauryloxy groups), alkoxy group (eg, , Methoxy, ethoxy, propoxy, butoxy, pentyloxy, heptyloxy, octyloxy groups), aryloxy groups (eg, phenoxy groups), alkoxycarbonyl groups (eg, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pen Ruoxycarbonyl, heptyloxycarbonyl groups), aryloxycarbonyl groups (eg, phenoxycarbonyl groups), alkoxycarbonylamino groups (eg, butoxycarbonylamino groups, hexyloxycarbonylamino groups), alkylthio groups (eg, methylthio, Ethylthio, propylthio, butylthio, pentylthio, heptylthio, octylthio groups), arylthio groups (eg, phenylthio groups), alkylsulfonyl groups (eg, methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pentylsulfonyl, heptylsulfonyl, octyl) Sulfonyl groups), amide groups (eg, acetamide, butyramide group, hexylamide, laurylamide groups) and non-aromatic heterocyclic groups (eg, morpholyl groups, Jiniru group) are included.

Among these, preferred substituents include halogen atoms, cyano groups, carboxyl groups, hydroxyl groups, amino groups, alkylamino groups, acyl groups, acyloxy groups, amide groups, alkoxycarbonyl groups, alkoxy groups, alkylthio groups, and alkyl groups. Can be mentioned.
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 the alkyl moiety and the substituent of the alkyl group include halogen atom, hydroxyl group, carboxyl group, cyano group, amino group, alkylamino group, nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group, sulfamoyl group, alkylsulfur group. Famoyl group, ureido group, alkylureido group, alkenyl group, alkynyl group, acyl group, acyloxy group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, Alkylsulfonyl groups, amide groups and non-aromatic heterocyclic groups are included. As the substituent for the alkyl moiety and the alkyl group, a halogen atom, a hydroxyl group, an amino group, an alkylamino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, and an 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 group or ethynylene group).
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. More preferably, it is 140 degrees or more and 220 degrees or less.
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 for Ar ¹ and Ar ^{2 in} formula (I).

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, still more preferably 1 to 6, still more preferably 1 to 4, and 1 or 2 (methylene group). Or ethylene group).
L ² and L ³ are particularly preferably —O—CO— or —CO—O—.

In the general formula (2), X represents a 1,4-cyclohexylene group, a vinylene group or an ethynylene group.
Specific examples of the compound represented by the general formula (1) 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.

In general formula (3), 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 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Represents an aryloxy group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 38 to 4012 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano 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 with reference to methods described in literature. References include Mol. Cryst. Liq. Cryst., 53, 229 (1979), 89, 93 (1982), 145, 111 (1987), 170, 43 Page (1989), J. Am. Chem. Soc., 113, 1349 (1991), 118, 5346 (1996), 92, 1582 (1970), J. Org Chem., 40, 420 (1975), Tetrahedron, 48, 16, 3437 (1992).
The addition amount of the retardation enhancer is preferably 0.1 to 30% by mass, and more preferably 0.5 to 20% by mass of the amount of the polymer.

  The aromatic compound is preferably used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of cellulose acetate. The aromatic compound is more preferably used in the range of 0.05 to 15 parts by mass and more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of cellulose acetate. Two or more kinds of compounds may be used in combination.

Next, the organic solvent in which the cellulose acylate of the present invention is dissolved will be described.
(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 by dissolving, casting, and forming a film of cellulose acylate. 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. The non-chlorine organic solvent used in combination with the chlorinated organic solvent in the present invention is described below.
That is, as a preferable non-chlorine organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Further, the ester, ketone, ether and alcohol 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.
Although the following can be mentioned as a combination of the chlorinated organic solvent which is a preferable main solvent of this invention, It is not limited to these.

Dichloromethane / acetone / methanol / ethanol / butanol (75/10/5/5/5, parts by mass),
Dichloromethane / acetone / methanol / propanol (80/10/5/5, parts by mass),
Dichloromethane / acetone / methanol / butanol / cyclohexane (75/10/5/5/5, parts by mass),
Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/5/5/7, parts by mass),
Dichloromethane / cyclopentanone / methanol / isopropanol (80/7/5/8, 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, parts 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 solvent)
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 an ester, a ketone and an ether (that is, —O—, —CO— and —COO—) can also be used as a main solvent. It may have a functional group. 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, a preferred solvent for the cellulose acylate of the present invention is a mixed solvent of three or more different from each other, and the first solvent is selected from methyl acetate, ethyl acetate, methyl formate, ethyl formate, acetone, dioxolane, and dioxane. And at least one kind or a mixture thereof, the second solvent is selected from ketones having 4 to 7 carbon atoms or acetoacetate, and the third solvent is alcohol or hydrocarbon having 1 to 10 carbon atoms More preferably, it is a C1-C8 alcohol. 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, or methyl acetyl acetate. It may be.

The alcohol as the third solvent may be linear, branched or cyclic, and is preferably a saturated aliphatic hydrocarbon among the hydrocarbons. 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, in particular. Are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol.

  The above three types of mixed solvents preferably contain a first solvent in a proportion of 20 to 95% by mass, a second solvent in a proportion of 2 to 60% by mass, and a third solvent in a proportion of 2 to 30% by mass, Furthermore, it is preferable that a 1st solvent is 30-90 mass%, a 2nd solvent is 3-50 mass%, and also 3-25 mass% of 3rd alcohol is contained. 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. In addition, when the first solvent is a mixed solution and the second solvent is not used, the first solvent is preferably contained in a ratio of 20 to 90% by mass and the third solvent in a ratio of 5 to 30% by mass, Furthermore, it is preferable that a 1st solvent is 30-86 mass%, and also a 3rd solvent is contained 7-25 mass%. The non-chlorine-based organic solvent used in the present invention is more specifically described in pages 12 to 16 of the Japan Society for Invention and Innovation Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Japan Society for Invention). It is described in detail. 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 (75/8/5/5/7, parts by mass)
Methyl acetate / cyclopentanone / methanol / isopropanol (80/7/5/8, parts by mass),
Methyl acetate / acetone / butanol (85/10/5, parts by mass),
Methyl acetate / cyclopentanone / acetone / methanol / butanol (60/15/14/5/6, 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, parts 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, parts 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, part by mass),
1,3 dioxolane / cyclohexanone / methyl ethyl ketone / methanol / ethanol / butanol (55/20/10/5/5/5, parts by mass)
Etc.
Furthermore, a cellulose acylate solution can also be prepared by the following method.
Prepare a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass), filter and concentrate, and then add 2 parts by weight of butanol.
Prepare a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (84/10/4/2, parts by mass), add 4 parts by weight of butanol after filtration and concentration;
-Make a cellulose acylate solution with methyl acetate / acetone / ethanol (84/10/6, parts by mass), filter and concentrate, then add 5 parts by weight of butanol.

(Characteristics of cellulose acylate solution)
In the present invention, the cellulose acylate is preferably dissolved in an organic solvent in an amount of 13 to 27% by mass, more preferably 15 to 25% by mass, and particularly preferably 15 to 20% by mass. preferable. The method for preparing cellulose acylate at these concentrations may be a predetermined concentration at the stage of dissolution, or prepared in advance as a low-concentration solution (for example, 9 to 14% by mass) and then a predetermined concentration step. It may be adjusted to a high concentration solution. Furthermore, after preparing a high concentration cellulose acylate solution in advance, various additives may be added to obtain a predetermined low concentration cellulose acylate solution, and any method can be used for the cellulose acylate of the present invention. If it is prepared so that it may become the said solution concentration range, there will be no problem in particular.

Next, in this invention, it is preferable that the aggregate molecular weight of the cellulose acylate of 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 aggregate molecular weight is 180,000 to 9 million. This aggregate 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 simultaneously obtained 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, definitions of the molecular weight of the aggregate, the inertial square radius, and the second virial coefficient will be described. These were measured using the static light scattering method according to the following method. Although the measurement was 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 was dried at 120 ° C. for 2 hours, and was 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, the solution and the solvent are filtered through a 0.2 μm Teflon filter. Then, static light scattering of the filtered solution was measured at intervals of 10 degrees from 30 degrees to 140 degrees at 25 ° C. using a light scattering measuring device (DLS-700 manufactured by Otsuka Electronics Co., Ltd.). The obtained data is analyzed by the BERRY plot method. In addition, the refractive index required for this analysis uses the value of the solvent calculated | required with the Abbe refractive system, and the refractive index gradient (dn / dc) uses the differential refractometer (Otsuka Electronics Co., Ltd. product DRM-1021). The measurement was performed using the solvent and the solution used for the light scattering measurement.

(Dope preparation)
Next, regarding the preparation of the cellulose acylate solution (dope) in the present invention, the dissolution method is not particularly limited, and it may be room temperature, 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-10-95854 -45950, JP-A-2000-53784, JP-A-11-322946, JP-A-11-322947, JP-A-2-276830, JP-A-2000-273239, JP-A-11-. No. 71463, JP-A No. 04-259511, JP-A No. 2000-273184, JP-A No. 11-323017, JP-A No. 11-302388, etc. describe methods for preparing cellulose acylate solutions. The methods for dissolving these cellulose acylates in the organic solvents described in the above publications can appropriately apply these techniques to the present invention within the scope of the present invention. These details are described in detail in pages 22 to 25 of the Japan Society for Invention and Innovation Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Japan Society of Invention and Innovation) for non-chlorine solvent systems. And can be done in this way. In addition, the cellulose acylate dope solution of the present invention is usually subjected to solution concentration and filtration, which is also the same as that of the Japan Society for Invention and Technology Publication No. 2001-1745 (issued March 15, 2001, Japan Institute of Invention). It is described in detail on page 25. 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.

  The concentration of the cellulose acylate solution is characterized in that a high-concentration dope can be obtained as described above, and a cellulose acylate solution having a high concentration and excellent stability can be obtained without depending on the means of concentration. 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.) and the like can be used.

  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, a filter having an absolute filtration accuracy of 0.1 to 100 μm is used, and a filter having an absolute filtration accuracy of 0.5 to 25 μm is preferably used. 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.

In the present invention, the cellulose acylate solution is preferably adjusted to have a certain range of viscosity. The viscosity is measured using, for example, a stress rheometer (CVO 120) manufactured by Bohlin Instruments, about 1 mL of the sample solution. Viscosity (unit: Pas) is measured under the condition of applying a displacement of 1% at a dope temperature of 33 ° C. and a frequency of 1 Hz.
The solution viscosity can be adjusted by the properties of cellulose acylate and the concentration of cellulose acylate. Viscosity characteristics inherent to cellulose acylate can be changed by adjusting the viscosity average polymerization degree and molecular weight distribution, as described in the synthesis method.

A preferred concentration of cellulose acylate is a cellulose acylate concentration of between 13 and 27% by mass as described in the cellulose acylate solution properties. As a result, the preferred viscosity of the resulting cellulose acylate solution is 10 to 70 Pas (measurement temperature 33 ° C.). If the viscosity is higher than this range, the fluidity is poor and filtration and casting become difficult. If the viscosity is low, the internal pressure of the casting die is low, and uniform casting cannot be performed in the width direction, and the thickness variation in the width direction tends to increase. The viscosity of the dope is more preferably 15 to 45 Pas, and most preferably 20 to 35 Pas.
If the solution viscosity is in the above-mentioned range, the burden of filtration is reduced, so that it is possible to use a filter medium having a smaller pore diameter and higher accuracy than the conventional one. As a result, the cellulose acylate film of the present invention has less foreign matter, and in particular, when incorporated in a liquid crystal display device and displaying black, it is possible to reduce so-called bright spot foreign matter that shines due to light leakage. .

(Film formation)
A method for producing a film using a cellulose acylate solution will be described. For the method and equipment for producing the cellulose acylate film of the present invention, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film are used. The dope (cellulose acylate solution) prepared 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 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 the metal support has substantially gone around. 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 preparing a cellulose acylate film by the solvent casting method, the prepared cellulose acylate solution (dope) is cast on a drum or a 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-A Nos. 2000-301555, 2000-301558, 7-032391, JP-A-3-193316, JP-A-5-086212, JP-A-62-237113, JP-A-2-276607. The techniques described in JP-A-55-014201, JP-A-2-111511, and JP-A-2-208650 can be applied 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.
Further, it may be formed into a film 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-low viscosity cellulose acylate solution is 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, the film is formed by peeling the film formed on the metal support using the first casting port and performing the second casting on the side in contact with the metal support surface using the two casting ports. For example, the method described in Japanese Patent Publication No. 44-20235 can be mentioned. 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 a casting port, a highly viscous solution can be extruded onto a metal support at the same time. Not only can it be produced, but also the use of a concentrated cellulose acylate solution can reduce the drying load and increase the film production speed.
In the case of co-casting, the inner and outer thicknesses are not particularly limited, but the outer side is preferably 1 to 50% of the total film thickness, 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. In addition, the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a 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 at the same temperature 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 degrees 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.

(Extension process)
The retardation of the cellulose acetate film of the present invention can be adjusted by stretching treatment. Furthermore, there is also a method of positively stretching in the width direction. -48271, and the like. In order to increase the in-plane retardation value of the cellulose acylate film, the produced film is stretched.
The film is stretched at room temperature or under heating conditions. The heating temperature is preferably not higher than the glass transition temperature of the film. The stretching of the film may be uniaxial stretching only in the longitudinal or lateral direction, or may be simultaneous or sequential biaxial stretching. Stretching is performed by 1 to 200%. The stretching is preferably 1 to 100%, particularly preferably 1 to 50%. 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, the stretching may be performed in a state including the residual solvent amount, and the stretching can be preferably performed at a residual solvent amount of 2 to 30%.

  In the present invention, the thickness of the finished cellulose acylate film (after drying) varies depending on the purpose of use, but is usually in the range of 5 to 500 μm, preferably in the range of 20 to 300 μm, particularly for VA liquid crystal display devices. Is preferably 40 to 110 μm. On the other hand, by setting the film thickness to 110 to 180 μm, the drying load during casting film formation becomes large, but the size of the optical characteristics is proportional to the film thickness, so the desired film thickness can be increased by increasing the film thickness. Optical properties can be achieved. Further, 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. Good results can be obtained in a polarizing plate durability test for 500 hours at 60 ° C. and 90% RH.

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, it is preferable to give a knurling to at least one end, the width is 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is 1 to 50 μm, preferably 2 to 20 μm, more preferably 3 to 10 μm. is there. This may be a single push or a double push.
The difference in film thickness in the width direction excluding the knurling part is preferably 5 μm or less, and more preferably 3 μm or less. When the film thickness difference in the width direction is large, when a long film exceeding 4000 m is wound, deformation due to the film thickness difference called a black belt is likely to occur. A sudden film thickness variation with a narrow width is not only a problem of vertical streak-like appearance, but also a problem of luminance unevenness when mounted on a liquid crystal display device. When the film thickness is measured continuously in the width direction, there is no film thickness difference exceeding 0.6 μm between 10 mm at any measurement location. The film thickness difference between 10 mm is preferably 0.5 μm or less.
In order to maintain transparency, the haze is preferably 0.01 to 2%. In order to reduce the haze, the added fine matting agent is sufficiently dispersed to reduce the number of aggregated particles, or the matting agent is used only in the skin layer in order to reduce the addition amount.

(Optical properties of cellulose acylate film)
The optical property Re retardation value and Rth retardation value of the cellulose acylate film of the present invention satisfy the following formulas (V) and (VI), respectively.
(V): 46 nm ≦ Re (630) ≦ 200 nm
(VI): 70 nm ≦ Rth (630) ≦ 350 nm
In the formulas (V) and (VI), Re (λ) is the front retardation value (unit: nm) at the wavelength λnm, and Rth (λ) is the retardation value (unit: nm) in the film thickness direction at the wavelength λnm. .
Re (λ) can be measured by making light having a wavelength of λ nm incident in the normal direction of the film using a birefringence meter such as KOBRA 21ADH (manufactured by Oji Scientific Instruments). 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. On the basis of this, it is possible to input and calculate the assumed average refractive index value of 1.48 and the film thickness.
More preferably, the following formulas (VII) and (VIII) are satisfied.
(VII): 46 nm ≦ Re (630) ≦ 100 nm
(VIII): 160 nm ≦ Rth (630) ≦ 350 nm
It is preferable for the VA liquid crystal display device using only one optical film and polarizing plate of the present invention to satisfy the following formulas (IX) and (X) in addition to the formulas (VII) and (VIII).
(IX): Rth (630) = a-5.9 Re (630) nm
(X): 520 ≦ a ≦ 600 nm
The central value of the y-intercept a of the straight line represented by the formula (IX) is 560 nm, and the black luminance value of the VA liquid crystal display device increases as a deviates from 560. That is, light is leaked and it is not black. Further, if a is shifted upward from 560, a change in color depending on the viewing angle of the liquid crystal display device becomes large, which is not preferable. Formula (X) shows the allowable range of the a value. Particularly for a VA liquid crystal display device using only one polarizing plate, 55 nm ≦ Re (630) ≦ 85 nm and 535 ≦ a ≦ 585 nm are preferable. Re (630) and Rth (630) vary depending on the Δnd value of the VA liquid crystal cell to be used. For example, when the Δnd value of the VA liquid crystal cell is 320 nm, the most preferable Re (630) and Rth (630) are 55 to 60 and 185 to 275, respectively. When the Δnd value of the VA liquid crystal cell is 300 nm, the most preferable Re (630) and Rth (630) are 60 to 65 and 160 to 240, respectively.
The variation in the Re value over the entire width is preferably ± 5 nm, and more preferably ± 3 nm. Further, the variation of the Rth value is preferably ± 10 nm, and more preferably ± 5 nm. Further, it is preferable that the variation in the Re value and the Rth value in the length direction is also within the range of the variation in the width direction.

The optical characteristic values of Re and Rth change with changes in mass and dimensional changes due to changes in humidity and aging. The smaller the change in the values of Re and Rth, the better. In addition to using cellulose acylate with a high degree of acyl substitution at the 6-position in order to reduce changes in optical properties due to humidity, by using various hydrophobic additives (plasticizer, retardation developer, ultraviolet absorber, etc.) Reduce the moisture permeability and equilibrium moisture content of the film. The preferred moisture permeability is 400 to 2300 g per square meter at 60 ° C. and 95% RH for 24 hours. A preferable equilibrium water content is 3.4% or less at 25 ° C. and 80% RH. When the humidity at 25 ° C. is changed from 10% RH to 80% RH, the amount of change in optical characteristics is preferably 12 nm or less in Re value and 32 nm or less in Rth value. A preferred amount of hydrophobic additive is 10 to 30%, more preferably 12 to 25%, particularly preferably 14.5% to 20%, based on cellulose acylate. When the additive is volatile or decomposable and changes in the mass or dimensions of the film occur, the optical properties change. Therefore, it is preferable that the mass change amount of the film after aging at 80 ° C. and 90% RH for 48 hours is 5% or less. Similarly, the dimensional change after 24 hours at 60 ° C. and 90% RH or after 24 hours at 90 ° C. and 3% RH is preferably within ± 2%. Even if there is a small dimensional change or mass change, if the photoelastic coefficient of the film is small, the amount of change in optical characteristics is small. Therefore it is preferable photoelastic coefficient of the film is ^{50 × 10 -13 cm 2 /dyn(5.0×10 -10} m 2 / N) or less.

(Polarizer)
The polarizing plate is composed of a polarizer and two transparent protective films disposed on both sides thereof. As one protective film, the cellulose acylate film of the present invention can be used. The other protective film may be 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. There is a method in which the obtained cellulose acylate film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Examples of the adhesive used to bond the protective film-treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like. The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and further comprises a protective film bonded to one surface of the polarizing plate and a separate film bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

The cellulosic acylate film of the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer coincides with the slow axis of the cellulose acylate film of the present invention. In addition, when the polarizing plate produced under polarizing plate crossed Nicols was evaluated, the orthogonality 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) was 1. It was found that when the angle was larger than 0 °, the polarization degree performance under the polarizing plate crossed Nicols deteriorated and light leakage occurred. In this case, when combined with a liquid crystal cell, sufficient black level and contrast cannot be obtained. Accordingly, the deviation between the direction of the main refractive index nx of the cellulose acylate film of the present invention and the direction of the transmission axis of the polarizing plate is preferably within 1 °, and preferably within 0.5 °.
The single plate transmittance TT, parallel transmittance PT, and orthogonal transmittance CT of the polarizing plate are measured using UV3100PC (manufactured by Shimadzu Corporation). The measurement was performed in the range of 380 nm to 780 nm, and the average value of 10 measurements was used for both single plate, parallel and orthogonal transmittance. The polarizing plate durability test was carried out as follows: (1) only the polarizing plate, (2) the polarizing plate attached to glass via an adhesive, and two types of forms. For the measurement of only the polarizing plate, two identical ones that are combined and orthogonally arranged so that an optical compensation film is sandwiched between two polarizers are measured. 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 single-plate transmittance measurement, the sample is set with the film side facing the light source. Each of the two samples is measured, and the average value is taken as the transmittance of the single plate. The preferable range of polarization performance is 40.0 ≦ TT ≦ 45, 0, 30.0 ≦ PT ≦ 40.0, CT ≦ 2 in the order of single plate transmittance TT, parallel transmittance PT, and orthogonal transmittance CT, respectively. 0.0, and more preferable ranges are 41.0 ≦ TT ≦ 44.5, 34 ≦ PT ≦ 39.0, and CT ≦ 1.3 (the unit is%). In the durability test of the polarizing plate, it is preferable that the amount of change is smaller.
In the polarizing plate of the present invention, the amount of change ΔCT (%) in orthogonal single plate transmittance and the amount of change in polarization ΔP when left at 60 ° C. and 95% RH for 500 hours have the following formulas (j) and (k ) Is satisfied.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
Here, the amount of change is a value obtained by subtracting the pre-test measurement value from the post-test measurement value.
Satisfying this requirement ensures stability during use or storage of the polarizing plate.

(Dampproof bag)
In the present invention, the “moisture-proof bag” is defined by the moisture permeability measured based on the cup method (JIS-Z208). 40 ° C., 90% R.D. H. It is preferable to use a material having a moisture permeability of 30 g / (m ² · Day) or less. When it is 30 g / (m ² · Day) or more, it becomes impossible to prevent the influence of environmental humidity outside the bag. More preferably, it is 10 g / (m ² · Day) or less, and most preferably 5 g / (m ² · Day) or less.
The material of the moisture-proof bag is not particularly limited as long as it satisfies the above-described moisture permeability, and any known material can be used [("Packaging Handbook", Japan Packaging Technology Association (1995)). ; "Basic knowledge of packaging materials", Japan Packaging Technology Association (November 2001); "Introduction to functional packaging", 21st century packaging research boundary (February 28, 2002, first edition, first print), etc.) . In the present invention, a material that has low moisture permeability and is light and easy to handle is desirable, and a composite material such as a film obtained by vapor-depositing silica, alumina, ceramics material, etc. on a plastic film or a laminated film of a plastic film and an aluminum foil is particularly preferably used. Can do. The thickness of the aluminum foil is not particularly limited as long as the humidity in the bag is not affected by the environmental humidity, but it is preferably several μm to several 100 μm, and preferably 10 μm to 500 μm. Further preferred. It is preferable that the humidity in the bag subjected to the moisture-proofing treatment used in the present invention satisfies any of the following.
43% RH to 70% RH at 25 ° C. with the polarizing plate packaged, more preferably 45% to 65%, and still more preferably 45% to 63%.
The humidity in the bag with the polarizing plate packaged is within 15% RH with respect to the humidity when the polarizing plate is bonded to the liquid crystal panel.

(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. 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 under a low pressure gas of 10 −3 to 20 Torr, and plasma treatment under atmospheric pressure is also preferred. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail on pages 30 to 32 in the Invention Association Public Technical Bulletin No. 2001-1745 (issued March 15, 2001, Invention Association). 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 because it is applied to the transparent support of the saponification solution, and the surface state remains good without forming irregularities on the surface of the transparent support by the saponification solution solvent. It is preferred to select a solvent to keep. 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.

(Antireflection layer)
It is preferable to provide a functional film such as an antireflection layer on the transparent protective film disposed on the opposite side of the polarizing plate from the liquid crystal cell. In particular, in the present invention, at least a light scattering layer and a low refractive index layer are laminated in this order on a transparent protective film, or a medium refractive index layer, a high refractive index layer, and a low refractive index layer are formed on this transparent 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 transparent protective film will be described.
The matting particles are dispersed in the light scattering layer according to the present invention, and the refractive index of the material other than the matting particles of the light scattering layer is preferably in the range of 1.50 to 2.00, and the low refractive index The refractive index of the layer is preferably in the range of 1.35 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.
Further, the ratio of the minimum value and the maximum value of the reflectance in the range of the a * value −2 to 2, the b * value −3 to 3, and the 380 nm to 780 nm in the light reflected by the C light source is 0.5. By setting it to -0.99, the color of the reflected light becomes neutral, which is preferable. Moreover, it is preferable that the b * value of the transmitted light under the C light source is 0 to 3 because the yellow color of white display when applied to an image display device is reduced.
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 the film of the present invention is applied is preferably reduced.

  When the antireflection layer according to the present invention has optical characteristics such as a specular reflectance of 2.5% or less, a transmittance of 90% or more, and a 60 ° gloss of 70% or less, reflection of external light can be suppressed, and visibility is improved. It is preferable because it 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 (ratio) is 0.3 to 1, and haze value decreases after forming a low refractive index layer from the haze value when the light scattering layer is provided. Within 15%, with a comb width of 0.5 mm, the transmitted image clarity is 20% to 50%, and the transmittance ratio of transmitted light perpendicular to the antireflection layer surface and transmitted light in a direction inclined by 2 degrees from the vertical is 1.5 to 5. Setting it to 0 is preferable because it prevents glare on a high-definition LCD panel and reduces blurring of characters and the like.

(Low refractive index layer)
The refractive index of the low refractive index layer of the antireflection film of the present invention is 1.20 to 1.49, preferably 1.30 to 1.44. Further, the low refractive index layer preferably satisfies the following formula (IX) from the viewpoint of low reflectance.
Formula (XI): (m / 4) × 0.7 <n ⁻⁴ d ⁻⁴ <(m / 4) × 1.3
In the formula, m is a positive odd number, n ⁻⁴ is the refractive index of the low refractive index layer, and d ⁻⁴ 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 of the present invention will be described below.
The low refractive index layer of the present invention 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 antireflection film 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 seal or memo, preferably 5N or less, more preferably 3N or less, Most preferred is 1N or less. 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 fluorine-containing monomer include 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)), a complete or partially fluorinated vinyl ether, and the like. Perfluoroolefins are preferred, and hexafluoropropylene is particularly preferred 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 advance in the molecule such as glycidyl (meth) acrylate and glycidyl vinyl ether, carboxyl groups, hydroxy groups, amino groups , Obtained by polymerization of a monomer having a sulfo group or the like (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc.) And a structural unit obtained by introducing a crosslinking reactive group such as a (meth) acryloyl group into these structural units by a polymer reaction (for example, it can be introduced by a technique such as allowing acrylic acid chloride 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. There are no particular limitations on the monomer units that can be used in combination. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2) -Ethylhexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl) Vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate etc.), acrylamides (N-tert-butylacrylamide, N- Black 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 surface scattering and / or 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

  The thickness of the light scattering layer is preferably from 1 to 10 μm, more preferably from 1.2 to 6 μm, from the viewpoint of imparting hard coat properties and from the viewpoint of curling and suppression of deterioration of brittleness.

  The binder of the 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.
Accordingly, 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 on a transparent support and then ionizing radiation or heat is applied. The antireflection film can be formed by curing by the polymerization reaction. 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.
Accordingly, a coating liquid containing a polyfunctional epoxy compound, a photoacid generator or a thermal acid generator, matte particles and an inorganic filler is prepared, and the coating liquid is applied onto a transparent support and then subjected to a polymerization reaction by ionizing radiation or heat. Curing can form an antireflection film.

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. Matt 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 of classification.

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 O 3, In 2 O 3, 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 1.48 to 2.00, more preferably 1.50 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 coating unevenness, drying unevenness, 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 an antiglare 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 transparent protective film will be described.
An antireflection film having a layer structure of at least a medium refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) on the substrate is designed to have a refractive index satisfying the following relationship.
The refractive index of the high refractive index layer> The refractive index of the medium refractive index layer> The refractive index of the transparent support> The refractive index of the low refractive index layer Further, a hard coat layer is provided between the transparent support and the medium refractive index layer. Also good. Further, it may be composed of a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer (for example, JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, (See JP 2002-243906, JP 2000-11706, etc.). Other functions may be imparted to each layer, and examples thereof include an antifouling low refractive index layer and an antistatic high refractive index layer (for example, JP-A-10-206603). JP, 2002-243906, A) etc. are mentioned.
The haze of the antireflection film 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 film is composed of a curable film containing at least an inorganic compound ultrafine 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 compounds having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.
In order to obtain such ultrafine particles, the surface of the particles is treated with a surface treating agent (for example, silane coupling agents, etc .: JP-A Nos. 1-295503, 11-153703, 2000-9908). , Anionic compounds or organometallic coupling agents: Japanese Patent Application Laid-Open No. 2001-310432, etc., a core-shell structure with high refractive index particles as a core (: Japanese Patent Application Laid-Open No. 2001-1661042001-310432, etc.), specific (For example, JP-A-11-153703, US Pat. No. 6,210,858, JP-A-2002-27776069, etc.) and the like.

Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.
Furthermore, a polyfunctional compound-containing composition having at least two radically polymerizable and / or cationically polymerizable groups, and a composition containing an organometallic compound having a hydrolyzable group and a partial condensate 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 generally 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 mμ, more preferably 10 nm to 1 μm.

(Low refractive index layer)
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 1.20 to 1.55. 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 refractive index of the fluorine-containing compound is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47. The fluorine-containing compound is preferably a compound containing a crosslinkable or polymerizable functional group containing fluorine atoms in the range of 35 to 80% by mass.
For example, paragraph numbers [0018] to [0026] of Japanese Patent Application Laid-Open No. 9-222503, paragraph numbers [0019] to [0030] of Japanese Patent Application Laid-Open No. 11-38202, and paragraph numbers of Japanese Patent Application Laid-Open No. 2001-40284. [0027] to [0028], compounds described in JP-A No. 2000-284102, and the like.
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 the fluorine-containing and / or siloxane polymer having a crosslinking or polymerizable group is carried out at the same time as or after the application of the coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer and the like. It is preferable to carry out by light irradiation or heating.
Also preferred is a cured film by sol-gel conversion 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. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820, etc.), silane coupling agents, slip agents, surfactants, and the like can be contained.
When the low refractive index layer is 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.

  Further, a hard coat layer, a forward scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

(Hard coat layer)
The hard coat layer is provided on the surface of the transparent support in order to impart physical strength to the transparent 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 a light and / or heat curable compound. The curable functional group is preferably a photopolymerizable functional group, and the hydrolyzable functional group-containing organometallic compound is preferably an organic alkoxysilyl compound.
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 WO 00/46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.
A hard-coat layer can also serve as the glare-proof layer (after-mentioned) which contained the particle | grains with an average particle diameter of 0.2-10 micrometers and provided the glare-proof function (anti-glare 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.

(Antistatic layer)
In the case of providing an antistatic layer, it is preferable to impart conductivity with a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less. The use of hygroscopic substances, water-soluble inorganic salts, certain surfactants, cationic polymers, anionic polymers, colloidal silica, etc. can give a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ). There is a problem that dependency is large, and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material. Some metal oxides are colored, but using these 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 coloring, and a metal oxide containing this as a main component should 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, or a composite oxide 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 secure a conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance, It is sufficient that the layer has a surface resistance value of approximately 10 ⁻¹⁰ (Ω / □) or less, and more preferably 10 ⁻⁸ (Ω / □). The surface resistance value of the conductive layer needs to be measured as a value when the antistatic layer is the outermost layer, and can be measured in the middle of forming the laminated film described in this patent.

(Liquid crystal display device)
The cellulose acylate film of the present invention, the optical compensation sheet comprising the film, and the polarizing plate using the film can be used in liquid crystal cells and liquid crystal display devices of various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal, AFLC) Various display modes such as HAN (Hybrid Aligned Nematic) have been proposed. Of these, the OCB mode or the VA mode can be preferably used.

  The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. OCB mode liquid crystal cells are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are aligned symmetrically between the upper part and the lower part of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

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).
The VA mode liquid crystal display device includes a liquid crystal cell and two polarizing plates disposed on both sides thereof. The liquid crystal cell carries a liquid crystal between two electrode substrates. In one aspect of the transmissive liquid crystal display device of the present invention, the optical compensation sheet of the present invention is disposed between the liquid crystal cell and one polarizing plate, or between the liquid crystal cell and both polarizing plates. Place two in between.

  In another aspect of the transmissive liquid crystal display device of the present invention, an optical compensation sheet made of the cellulose acylate film of the present invention is used as the transparent protective film of the polarizing plate disposed between the liquid crystal cell and the polarizer. The above optical compensation sheet may be used only for the transparent protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, or between the polarizing plates (between the liquid crystal cell and the polarizer). The above optical compensation sheet may be used for the two transparent protective films. When the optical compensation sheet is used only for one polarizing plate, it is particularly preferable to use it as a protective film for the liquid crystal cell side of the backlight side polarizing plate of the liquid crystal cell. The cellulose acylate film of the present invention is preferably bonded to the liquid crystal cell on the VA cell side. The protective film may be a normal cellulose acylate film, and is preferably thinner than the cellulose acylate film of the present invention. For example, it is preferably 40 to 80 μm, and examples thereof include, but are not limited to, commercially available KC4UX2M (40 μm manufactured by Konica Capto Corporation), KC5UX (60 μm manufactured by Konica Capto Corporation), 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.
[Measurement method]
Hereinafter, various properties of the cellulose acylate film were measured and measured by the following methods.
(Retardation Re, Rth)
Retardation was measured using a birefringence meter (KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.)) with light having a wavelength of λ nm incident in the normal direction of the film. A retardation value measured by injecting light of wavelength λ nm from a direction inclined + 40 ° with respect to the normal direction of the film with the in-plane slow axis as the tilt axis, and a film with the in-plane slow axis as the tilt axis Based on the retardation values measured in a total of three directions, the retardation value measured by making light of wavelength λ nm incident from a direction inclined by −40 ° with respect to the normal direction, the assumed average refractive index of 1.48 The film thickness was input and calculated.
(Moisture content)
A 7 mm × 35 mm sample was conditioned at 25 ° C. and 80% RH for 2 hours, and measured with a Karl Fischer method trace moisture meter LE-20S (manufactured by Hiranuma Sangyo Co., Ltd.). The water content was calculated by dividing the moisture content (g) in the sample by the sample mass (g).

(Heat shrinkage)
Sample 30 mm × 120 mm was aged for 2 hours at 25 ° C. and 60% RH, 6 mmφ holes were made at both ends at 100 mm intervals, and the automatic punch gauge (Shinto Kagaku Co., Ltd.) was used to determine the original punch spacing (L1). Measurement was made to a minimum scale of 1/1000 mm. Furthermore, it was left to stand at 60 ° C., 90% RH or 90 ° C., 3% RH for 24 hours, and again aged at 25 ° C. and 60% RH for 2 hours, and the dimension (L2) of the punch interval was measured. And the thermal contraction rate was calculated | required by {(L1-L2) / L1} * 100.
(Glass transition temperature Tg)
Grasp a film sample (unstretched) 5 mm x 30 mm with a dynamic viscoelasticity measuring device (Vibron, DVA-225 (manufactured by IT Measurement Control Co., Ltd.)) after conditioning it at 25 ° C and 60% RH for 2 hours or more. (Gripping point) Viscoelasticity is measured at a distance of 20 mm, a temperature increase rate of 2 ° C./minute, a measurement temperature range of 30 ° C., 200 ° C., and a frequency of 1 Hz, the logarithmic axis is the storage elastic modulus, and the horizontal axis is the linear axis. The temperature (° C.) was taken and plotted. At that time, a straight line 1 is drawn when a straight line 1 is drawn in the solid region and a straight line 2 is drawn in the glass transition region. The intersection of the straight lines 2 is the temperature at which the storage elastic modulus suddenly decreases and the film begins to soften at the time of temperature rise, and is the temperature at which the film begins to move to the glass transition region, so the glass transition temperature Tg (dynamic viscoelasticity) is used. .

(Number of bright spot foreign matter)
Using a polarizing microscope, the upper and lower polarizing plates of the sample film are adjusted to a crossed Nicol state, each sample is observed 30 points at a magnification of 50 times, and recorded as a digital image at a recording density of 1280 × 1024 dots. At this time, the observation range was 2.16 mm × 1.72 mm. Adjust the image magnification so that it becomes 108 mm x 86 mm, observe the image on a personal computer screen, count the number of foreign particles that shine white with a major axis of 1 mm or more on the image, and total 30 particles for each sample. Was measured data.
(Filtration blockage factor)
A filter paper (hole diameter 47 μm, thickness 1.32 mm, density 0.32 g / m ³ ) supported by a porous plate having 61 holes with a diameter of 3.8 mm in a disk with an effective area of 12.5 cm ² , 36 The cellulose acylate solution kept at 0 ° C. was filtered at a flow rate of 7 ml / min, and an increase in pressure was observed for 3.5 to 4 hours after the filtration pressure was temporarily stabilized. A graph was prepared by plotting filtration time on the horizontal axis and P0 / P ^0.64 plotted on the vertical axis, and a linear approximation formula of the plot was obtained. P and P0 represent the filtration pressure and the initial filtration pressure.
By substituting the obtained slope of the straight line into the filtration blockage coefficient equation [−Ks = 3.5 × slope], the filtration blockage coefficient Ks is calculated. Here, the pore diameter of the filter paper used is a value calculated from the bubble point value of the filter paper. A gear pump (KA1 manufactured by Kawasaki Heavy Industries) was used for liquid feeding.

(Elastic modulus)
Sample 10mm × 200mm was conditioned at 25 ° C, 60% RH for 2 hours, and the tensile modulus was initially measured with a tensile tester (Strograph-R2 (manufactured by Toyo Seiki)) at an initial sample length of 100 mm and a tensile speed of 100 mm / min. It was calculated from the stress and elongation.

(Photoelastic coefficient)
A tensile stress was applied to the long axis direction of a 10 mm × 100 mm film sample, and the Re retardation at that time was measured with an ellipsometer (M150, JASCO Corporation), and the photoelastic coefficient was calculated from the amount of change in retardation with respect to the stress. Was calculated.
(Haze)
A sample of 40 mm × 80 mm was measured according to JIS K6714 with a haze meter (HGM-2DP, Suga Test Instruments) at 25 ° C. and 60% RH.

[Example 1]
Formation of Cellulose Acylate Film (1) Cellulose Acylate Cellulose acylates with different degrees of acyl substitution described in Table 1 were prepared. These can be prepared by adding sulfuric acid as a catalyst, adding carboxylic acid and carboxylic anhydride to carry out an acylation reaction, then neutralizing and saponifying and aging, but adding a catalyst and neutralizing agent By adjusting the amount, the amount of water added, the reaction temperature, and the aging temperature, cellulose acylates having various total substitution degrees, 6-position substitution degrees, bulk specific gravities, and polymerization degrees can be obtained. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.

(2) Preparation of dope <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, and then a filter paper having an average pore size of 34 μm. Was used for constant flow filtration. All solutions had a blockage coefficient calculated between 200 m ^-3 and 500 m ^-3 . The solution after filter paper filtration was further filtered through a sintered metal filter having an average pore size of 10 μm.
―――――――――――――――――――――――――――――――――
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 size of 16 nm (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd. 2.0 parts by mass methylene chloride 72.4 parts by mass methanol 10.8 parts by mass cellulose acylate solution 10.3 parts by mass ―――――――――――――――――――――――――――

<1-3> Retardation developer solution A
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 A.
―――――――――――――――――――――――――――――――――
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 so as to have the ratio shown in Table 2 to prepare a dope for film formation. This dope was subjected to film production from F1 to F5 and from F8 to F14.
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 2 to prepare a dope for film formation. This dope was used for film formation of F6 and F7.
The addition ratio of the retardation developer is shown in Table 2 in terms of parts by mass when the amount of cellulose acylate is 100 parts by mass. Table 2 also shows the viscosity of the dope at 33 ° C.
Retardation developer B

(Casting)
The above dope was cast using a band casting machine. A film peeled off from the band with a residual solvent amount of 25 to 35% by mass is stretched in the width direction at a stretch rate of 15% to 25% (described in Table 2) using a tenter to produce a cellulose acylate film. did. The tenter was stretched in the width direction while being dried by applying hot air, and then contracted by about 5%, then transferred from the tenter conveyance to the roll conveyance, further dried, knurled and wound up with a width of 1500 mm. Table 2 shows the stretch ratio calculated from the film width at the tenter inlet and the film width at the tenter outlet.

  About the produced cellulose acylate film (optical compensation sheet), Re retardation value and Rth letter at a wavelength of 630 nm at 25 ° C. and 60% RH using a birefringence meter (KOBRA 21ADH (manufactured by Oji Scientific Instruments)) The film was conditioned at 25 ° C., 10% RH, 25 ° C., and 80% RH for 2 hours or more, and the Re retardation value and Rth retardation value at a wavelength of 630 nm were measured. Change of retardation of cellulose acylate film from 80% RH to 10% RH (Re (10% RH) -Re (80% RH), Rth (10% RH) -Rth (80% RH)) Are shown in Table 2 as ΔRe and ΔRth, and the film thickness in the width direction is measured with a continuous film thickness measuring instrument manufactured by Anritsu Electric. , The film thickness difference in the full width except the knurling portion, and are shown in Table 2 to measure the maximum film thickness variation value between 10 mm. Further, by measuring the bright spot of foreign matter, as shown in Table 2.

The glass transition temperature (Tg) of the prepared film was between 138 ° C and 147 ° C. The moisture content after humidity adjustment at 25 ° C. and 80% RH was between 2.9% and 3.4%. The water permeability for 24 hours at 60 ° C. and 95% RH was 800 to 2000 g / m ² / day. The hazes of these films are all 0.1 to 0.9, the secondary average particle size of the matting agent is 1.0 μm or less, the tensile elastic modulus is 4 GPa or more, 48 under the conditions of 80 ° C. and 90% RH. The mass change at the time of standing still was 0 to 3%. Moreover, the dimensional change when it left still for 24 hours on the conditions of 60 degreeC, 90% RH, 90 degreeC, and 3% RH was -1.2 to 0.2%. Further, in all samples, the photoelastic coefficient was 50 × 10 ⁻¹³ cm ² / dyn (5 × 10 ⁻¹¹ m ² / N) or less.

When a film having an optical film F13 shown in Table 2 having a film thickness after drying of 1.5 times 138 μm and 1.9 times 176 μm was prepared, Re and Rth increased depending on the film thickness. The rate was almost inversely proportional to the film thickness. Further, the humidity dependence ΔRe, ΔRth, glass transition temperature Tg, and moisture content of Re and Rth were the same regardless of the film thickness.
Next, using an ellipsometer (M-150: manufactured by JASCO Corporation), Re and Rth were measured by changing the wavelength at 25 ° C. and 60% RH environmental humidity. According to this measured value, the test sample described as an example in the remarks of Table 2 satisfies the requirements of the present invention (46 ≦ Re (630) ≦ 200, 70 ≦ Rth (630) ≦ 350, and the thickness in the width direction. It can be seen that the sample as a comparative example is not satisfied. Other optical films excluding F1 are 0.90 ≦ Re (450) / Re (550) ≦ 1.10, 0.90 ≦ Re (650) / Re (550) ≦ 1.10, 0.90. ≦ Rth (450) / Rth (550) ≦ 1.25 and 0.90 ≦ Rth (650) / Rth (550) ≦ 1.10.
On the other hand, F1 is 0.7 ≦ Re (450) / Re (550) ≦ 0.8, 1.1 ≦ Re (650) / Re (550) ≦ 1.2, 0.90 ≦ Rth (450) / Rth. (550) ≦ 1.25 and 0.90 ≦ Rth (650) / Rth (550) ≦ 1.10.

About the sample film of film No. F4 of Table 2, the detail about the manufacturing conditions at the time of casting and the obtained film physical property and measurement conditions are described collectively below.
<Production conditions>
Residual solvent amount at peeling 35% by mass
A zone tension 100N / m
Zone A end point methanol / (methylene chloride + methanol)
26% by mass
Stretching speed in process C 24% / min
Film atmosphere temperature of process C 140 ° C
Step C Stretch ratio 1.25 times Film temperature at the start of stretching 47 ° C
Film residual solvent amount at the start of stretching 34% by mass
Film temperature at the end of stretching 108 ° C
At the end of stretching Methanol / (methylene chloride + methanol)
4% by mass
Methylene chloride atmosphere concentration of process B 18vol%
Methylene chloride atmosphere concentration of process C 18vol%
<Remark>
Process A Process after peeling the cast film and then transporting it to the tenter part Process B for gripping the edge of the width in the tenter part Process for extending in the width direction in the tenter part

<Measurement method>
Residual solvent amount Residual solvent amount of film = ((A−B) / A) × 100
A: Weight at the time of sampling of the film B: Weight after the film was dried at 120 ° C. for 2 hours Ratio of methanol and methylene chloride: Determined by quantitative determination of methylene chloride and methanol in the film by gas chromatography.

<Physical properties of the obtained film>
Re 62nm
Rth 225nm
Orientation angle distribution ± 0.5 ° within retardation distribution (Re) 2.7%
Retardation distribution (Rth) 1.3%
Film thickness R (ave) 86.0 μm
Maximum film thickness R (max) 87.6 μm
Minimum film thickness R (min) 84.6 μm
Haze 0.7%
Dimensional change rate (MD) -0.05%
Dimensional change rate (TD) + 0.08%
Tear strength (MD) 23g
Tear strength (TD) 28g
Elastic modulus (MD) 400kgf / mm ²
Elastic modulus (TD) 487 kgf / mm ²
Stress at break (MD) 7.9 kgf / mm ²
Stress at break (TD) 11 kgf / mm ²
(Note) 1 kgf / mm ² is 9.8 MPa.
Elongation at break (MD) 17%
Elongation at break (TD) 12%

<Measurement method>
a) Orientation angle distribution measuring device KOBRA 21DH (manufactured by Oji Scientific Instruments)
Temperature / humidity 25 ° C, 60%, measurement conditions after humidity adjustment for 2 hours In low phase difference mode (order 1), 13 orientation angles are measured every 10 cm b) Retardation distribution measuring device KOBRA 21DH (Oji Scientific Instruments Co., Ltd.) ) Made)
Temperature / humidity 25 ° C, 60%, measurement conditions after humidity adjustment for 2 hours Re and Rth values at 630 nm wavelength in the width direction
7 points measured every 20cm
Retardation distribution = (maximum value−minimum value) / average value × 100
c) Haze measuring device Turbidimeter NDH2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.)
Measurement conditions JIS K-6714
d) Dimensional change rate measurement device Pin gauge Sample size 250mm x 50mm, Reference length approx. 200mm
Procedure Measure reference length L1 and sample
After 24 hours in a constant temperature and humidity chamber of 60 ° C. and 90% RH,
Measure the reference length L2 after conditioning for 2 hours at 25 ° C and 60% RH

Dimensional change rate (%) = ((L2-L1) / L1) × 100

e) Tear Strength Measuring Device Light Weight Tear Tester (manufactured by Toyo Seiki Seisakusho)
Range 0-90g
Weight 90g
Sample size 64 × 51mm
Temperature / humidity 25 ° C, 65%, measured after humidity control for 2 hours f) Stress at break, judgment point progress, elastic modulus Measuring device Strograph R2 type (Toyo Seiki Seisakusho Co., Ltd.)
Sample size 10mm wide x 100mm between chucks
Temperature / humidity 25 ° C., 60%, measurement after humidity control for 2 hours, stretching speed 10 mm / mim

[Comparative Example 1]
A cellulose acylate solution was prepared in the same manner as in Example 1 except that the amount of cellulose acylate in the cellulose acylate solution composition table of Example 2 (2) dope preparation was 120.0 parts by mass. As the cellulose acylate, CA5 shown in Table 1 was used. Subsequently, the prepared solution was filtered using the same filter paper having an average pore diameter of 34 μm as used in Example 1. The initial filtration pressure was 4 times the initial filtration pressure of the cellulose acylate solution used for the film F12 prepared in Example 1. Was as large as 1117M ^-3 in the present comparative example with respect to 305 meters ^-3 occlusion coefficients F12 creation solution. Moreover, it turned out that the filtration amount until the filtration pressure which is a standard which replaces | exchanges a filter medium reaches | attains 0.8 Mpa is significantly reduced with 1/5 compared with the filtration amount of the solution for F12 preparation, and practicality is scarce.

[Example 2]
<2-1-1>
(Preparation of polarizing plate-1)
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film.
The cellulose acylate film (F1 to F14: corresponding to TAC1 in FIGS. 1 to 3) prepared in Example 1 was 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.
Commercially available cellulose triacylate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd .: functional film TAC2 in FIG. 2, equivalent to TAC2-1 or 2-2 in FIG. 3) is subjected to saponification treatment to obtain a 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 in parallel (FIG. 1). 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.
Using a spectrophotometer (UV3100PC), the single plate transmittance TT, parallel transmittance PT of a polarizing plate of 380 nm to 780 nm are combined so that the cellulose acylate film prepared in Example 1 comes inside the polarizer. When orthogonal transmittance CT was measured and the average value of 400-700 nm was calculated | required, TT was 40.8-44.7, PT was 34-38.8, and CT was 1.0 or less. Further, in the polarizing plate durability test at 60 ° C. and 95% RH for 500 hours, both are in 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.
The thus-prepared polarizing plates A1 to A14 (the optical compensation film-integrated polarizing plate having no functional film in FIG. 2) are partly stored in a moisture-proof bag and the other part is 25. After conditioning for 2 hours at a temperature of C60% RH, the product was stored in a moisture-proof bag. The moisture-proof bag was a packaging material having a laminated structure of polyethylene terephthalate / aluminum / polyethylene, and the moisture permeability was 0.01 mg / m ² (24 hours) or less.

<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 (Fujitac TD80UF, 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, depth Using a microgravure roll with a diameter of 50 mm and a doctor blade having a gravure pattern of 40 μm, coating was performed under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 30 m / min, drying at 60 ° C. for 150 seconds, and further under nitrogen purge Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 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 functional layer having a thickness of 6 μm 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 nitrogen purge, irradiance was irradiated with ultraviolet rays of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ^2. A refractive index layer was formed and wound up (corresponding to the functional film TAC2 in FIG. 2 or TAC2-1 in FIG. 3).

<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 (F1 to F14: equivalent to TAC1 in FIG. 1) was subjected to the same saponification treatment and attached to the opposite side of the polarizer using a polyvinyl alcohol-based adhesive. It dried for 10 minutes or more at the degree C (the form which the structure of FIG. 2 was completed).
The transmission axis of the polarizer and the slow axis of the cellulose acylate film produced in Example 1 were arranged in parallel (FIG. 1). The transmission axis of the polarizer and the slow axis of the transparent anti-reflection film 01 with the light scattering layer were arranged so as to be orthogonal to each other. In this way, polarizing plates (B1 to B14: functional film and optical compensation film integrated polarizing plate (FIG. 2)) were produced. In the same manner as the production of the polarizing plate <2-1-1>, a sample that was put in a moisture-proof bag after humidity conditioning at 25 ° C. 60% RH and a sample that was put in a moisture-proof bag without humidity conditioning were prepared.
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film. The transparent protective film 01 with the light scattering layer prepared in <2-2-3> and the triacetylcellulose film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm without applying the functional layer are described above. The saponification treatment was performed in the same manner as that described above, and was bonded to a polarizer in the same manner as described above using a polyvinyl alcohol-based adhesive. In this way, a polarizing plate (B0: functional film, optical compensation film integrated polarizing plate (FIG. 2)) was prepared. In the same manner as the production <2-1-1> of the polarizing plate, a product put in a moisture-proof bag after humidity control and a product put in a moisture-proof bag without conditioning were 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%.

<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.

<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. The solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a high refractive index layer.

<2-4-5>
(Preparation of coating solution for low refractive index layer)
A copolymer having the following structure 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. The photo-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.

<2-4-6>
(Preparation of transparent protective film 02 with antireflection layer)
A hard coat layer coating solution was applied onto a triacetylcellulose film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm using a gravure coater. After drying at 100 ° C., using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0 vol% or less, an irradiance of 400 mW / The coating layer was cured by irradiating ultraviolet rays having a cm ² and an irradiation energy 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 product was manufactured with an irradiance of 400 mW / cm ² and an irradiation energy amount of 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 for irradiation with an illuminance of 600 mW / cm ² and an irradiation energy 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. In this way, a transparent protective film 02 with an antireflection layer was produced (corresponding to the functional film TAC2 in FIG. 2 or TAC2-1 in FIG. 3).

<2-5-1>
(Preparation of polarizing plate-3)
A polarizing plate (C1 to C14: functional film, optical compensation film) is the same as <2-3-1> except that the transparent protective film 02 with an antireflection layer is used instead of the transparent protective film 01 with a light scattering layer. A body-type polarizing plate (FIG. 2) was produced. In the same manner, a polarizing film comprising a transparent protective film 02 with an antireflection layer, a triacetylcellulose film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm without applying a polarizer and a functional layer. A 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. 3 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.

A commercially available super high contrast product (for example, HLC2-5618 manufactured by Sanlitz Co., Ltd.) is used for the upper polarizing plate (observer side) of the liquid crystal display device (FIG. 3) using the vertical alignment type liquid crystal cell. It was. For the lower polarizing plate (backlight side), the polarizing plate (A3 to A10) prepared in <2-1-1> of Example 2 using the optical compensation sheet of F3 to F10 prepared in Example 1, The cellulose acylate film prepared in Example 1 (corresponding to TAC1-2 in FIG. 3) 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. The polarizing plate to be used is both the one that has been stored in a moisture-proof and moisture-proof bag for 2 hours under the temperature and humidity conditions of 25 degrees C and 60% RH, and the one that has been stored in a bag without humidity control. A liquid crystal display device was created.
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. However, although the polarizing plates A5 and A10 used were faint, streaky irregularities were visible. 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).
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 left in a room at room temperature and normal humidity (no humidity control at about 25 ° C. and 60% RH) for one week, and the color at the time of black display was measured again.
Table 3 below shows the measurement of viewing angle and color change. All of the examples had a wide viewing angle and little color change. In the case where the humidity of the polarizing plate was adjusted before assembling the liquid crystal display device, the color change was particularly small.

[Example 3-2]
<2-1-1 of Example 2 using the optical compensation sheet of F3 to F10 produced in Example 1 for the lower polarizing plate of the liquid crystal display device (FIG. 3) 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 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 air-conditioning was performed so that the temperature of the workplace was 20 to 25 ° C. and the humidity was 50 to 70% RH. The polarizing plates to be used are both those stored in a moisture-proof and moisture-proof bag for 2 hours under the temperature and humidity conditions of 25 ° C. and 60% RH, and those stored in a bag without humidity control. A liquid crystal display device was created.
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 the case of using the polarizing plates A5 and A10, streaky irregularities were observed. Further, as in Example 3-1, the viewing angle and the color change were measured, and the results are shown in Table 3.

[Example 3-3]
A liquid crystal display device (FIG. 3) was prepared using the same vertical alignment type liquid crystal cell as in Example 3-1, except that the cell gap was 2.8 mm and the value of Δn · d was 230 nm. The polarizing plate (A13 to A14) prepared in <2-1-1> of Example 2 is used for the lower polarizing plate of the manufactured liquid crystal display device, and <2-5-1> of Example 2 is used for the upper polarizing plate. The polarizing plate (C0) prepared in (1) was attached 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 air-conditioning was performed so that the temperature of the workplace was 20 to 25 ° C. and the humidity was 50 to 70% RH. The polarizing plates to be used are both those that have been pre-conditioned for 2 hours at 25 ° C. and 60% RH and stored in a moisture-proof bag, and those that have been stored in a bag without humidity control. A liquid crystal display device was produced using the liquid crystal display device.
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. Further, as in Example 3-1, the viewing angle and the color change were measured, and the results are shown in Table 3.

[Comparative Example 3-1]
The same procedure as in Example 3-1 was performed except that the lower polarizing plate of Example 3-1 was A1, B1, A2, and B2. The polarizing plate used here was not conditioned.
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. Further, as in Example 3-1, the viewing angle and the color change were measured, and the results are shown in Table 3.

  In Table 3, each sample of Example 3-1 to Example 3-3 of the present invention has a sufficiently wide viewing angle and color stability over time. It is shown that it is remarkably superior.

[Example 4]
The following composition was prepared by mixing in a total of 3 kg of glass bottles, and stirred at 25 ° C. at a rotation speed of 150 rpm for 3 hours to prepare a cellulose acylate solution.
―――――――――――――――――――――――――――――――――
Cellulose acylate solution ――――――――――――――――――――――――――――――――――
Cellulose acylate listed in Table 1 17.01% by mass
Triphenyl phosphate 1.16% by mass
Biphenyl diphenyl phosphate 0.83 mass%
Methylene chloride 7 0.47% by mass
Methanol 10.53 mass%
―――――――――――――――――――――――――――――――――

A filter paper (hole diameter 47 μm, thickness 1.32 mm, density 0.32 g / m ³ ) supported by a porous plate having 61 holes with a diameter of 3.8 mm in a disk with an effective area of 12.5 cm ² , 36 The cellulose acylate solution kept at 0 ° C. was filtered at a flow rate of 7 ml / min. An increase in pressure was observed for 3.5 to 4 hours after the filtration pressure was temporarily stabilized. A graph was prepared by plotting filtration time on the horizontal axis and P0 / P ^0.64 plotted on the vertical axis, and a linear approximation formula of the plot was obtained. P and P0 represent the filtration pressure and the initial filtration pressure. From the obtained slope of the straight line, the blockage coefficient Ks was calculated from the equation [−Ks = 3.5 × slope], and Table 4 shows the result.

It is a schematic diagram which shows the 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 the cross-section of the polarizing plate of this invention. It is sectional drawing which shows typically the cross-section of the liquid crystal display device of this invention.

Claims (31)

The front retardation Re (λ) is 46 ≦ Re (630) ≦ 200, the retardation Rth (λ) in the film thickness direction is 70 ≦ Rth (630) ≦ 350, and any 10 mm in the width direction is 10 mm. An optical cellulose acylate film having a thickness variation of 0.6 μm or less.
[Where Re (λ) is the front retardation (Re) value (unit: nm) at wavelength λnm, and Rth (λ) is the thickness direction retardation (Rth) value (unit: nm) at wavelength λnm. . ]   2. The optical cellulose acylate film according to claim 1, obtained by casting a dope having a viscosity at 33 ° C. of 10 Pas to 70 Pas.   3. The cellulose acylate film for optical use according to claim 1 or 2, wherein the degree of polymerization of the cellulose acylate is 265 or more and 380 or less.   4. The cellulose acylate film for optical use according to claim 1, wherein the bulk specific gravity of the cellulose acylate is 0.30 or more and 0.80 or less. A film made of cellulose acylate obtained by substituting the hydroxyl group of the glucose unit constituting cellulose with an acyl group having 2 or more carbon atoms, wherein the substitution degree of the hydroxyl group at the 2-position of the glucose unit with the acyl group is DS2 The following formulas (I) and (II) are satisfied, where DS3 represents the substitution degree of the hydroxyl group at the 3-position with an acyl group, and DS6 represents the substitution degree with the acyl group of the hydroxyl group at the 6-position. The optical cellulose acylate film in any one of -4.
(I): 2.0 ≦ DS2 + DS3 + DS6 ≦ 2.85
(II): DS6 / (DS2 + DS3 + DS6) ≧ 0.315   The optical cellulose acylate film according to claim 1, comprising at least one retardation developer comprising 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 film thickness of a film is 40-180 micrometers, The cellulose acylate film for optics in any one of Claims 1-7 characterized by the above-mentioned.   Content of the additive added to this cellulose acylate is 10 to 30 mass% of film mass, The cellulose acylate film for optics in any one of Claims 1-8 characterized by the above-mentioned.   The difference ΔRe (= Re 10% RH−Re 80% RH) between Re (Re 10% RH) value at 25 ° C. and 10% RH and Re (Re 80% RH) value at 25 ° C. and 80% RH is 12 nm or less. The difference ΔRth (= Rth10% RH−Rth80% RH) between the Rth (Rth10% RH) value at 10% RH and the Rth (Rth80% RH) value at 25 ° C. and 80% RH is 32 nm or less. The cellulose acylate film for optics according to any one of claims 1 to 9.   The optical cellulose acylate film according to any one of claims 1 to 10, wherein an equilibrium moisture content at 25 ° C and 80% RH is 3.4% or less. The optical fiber cellulose acylate according to any one of claims 1 to 11, which has a moisture permeability (converted to a film thickness of 80 µm) at 60 ° C and 95% RH for 24 hours of 400 g / m ² · 24 hr to 2300 g / m ² · 24 hr. Rate film.   The optical cellulose acylate film according to any one of claims 1 to 12, wherein a mass change is 0 to 5% when left to stand at 80 ° C and 90% RH for 48 hours.   The dimensional change when left at 60 ° C and 90% RH for 24 hours and the dimensional change when left at 90 ° C and 3% RH for 24 hours are both within ± 2%. The optical cellulose acylate film according to claim 1, wherein the optical cellulose acylate film is provided.   Glass transition temperature Tg is 80-180 degreeC, The cellulose acylate film for optics of Claims 1-14 characterized by the above-mentioned.   The optical cellulose acylate film according to claim 1, wherein the elastic modulus is 1500 to 5000 MPa. The optical cellulose acylate film according to claim 1, which has a photoelastic coefficient of 50 × 10 ⁻¹³ cm ² / dyn (5 × 10 ⁻¹¹ Pa−1) or less.   The optical cellulose acylate film according to claim 1, having a haze of 0.01 to 2%.   The optical cellulose acylate film according to claim 1, comprising silicon dioxide fine particles having a secondary average particle size of 0.2 or more and 1.5 μm or less. The relationship of the following (D) and (E) is established between the Re value and the Rth value measured by changing the wavelength at 25 ° C. and 60% RH environmental humidity. The cellulose acylate film for optical use according to 1.
(D): 0.90 ≦ Re (450) / Re (550) ≦ 1.10 and 0.90 ≦ Re (650) / Re (550) ≦ 1.10.
(E): 0.90 ≦ Rth (450) / Rth (550) ≦ 1.25 and 0.90 ≦ Rth (650) / Rth (550) ≦ 1.10.   The optical cellulose acylate film according to any one of claims 1 to 20, wherein the number of bright spot foreign matters having a major axis of 20 µm or more is 20 or less.   A polarizing plate comprising at least one of the optical cellulose acylate films according to claim 1 as a protective film for a polarizer. The single plate transmittance TT (%), parallel transmittance PT (%), orthogonal transmittance CT (%) and polarization degree P measured under the conditions of 25 ° C. and 60% RH of the polarizing plate are the following formulas (a) to The polarizing plate according to claim 22, wherein at least one of (d) is satisfied.
(A) 40.0 ≦ TT ≦ 45.0
(B) 30.0 ≦ PT ≦ 40.0
(C) CT ≦ 2.0
(D) 95.0 ≦ P The orthogonal single plate transmittance change ΔCT (%) and polarization degree change ΔP when left at 60 ° C. and 95% RH for 500 hours satisfy at least one of the following formulas (j) and (k). The polarizing plate according to claim 22 or 23.
(J) −6.0 ≦ ΔCT ≦ 6.0
(K) -10.0 ≦ ΔP ≦ 0.0
(Here, the amount of change indicates the value obtained by subtracting the measured value before the test from the measured value after the test.)   The surface of the protective film arrange | positioned on the opposite side to the liquid crystal cell of a polarizing plate provided the hard coat layer, the glare-proof layer, and the anti-reflective layer at least one layer, The any one of Claims 22-24 characterized by the above-mentioned. Polarizer.   The polarized light according to any one of claims 22 to 25, wherein the polarized light is packaged in a bag subjected to moisture-proof treatment, and the humidity in the packaged state is 43% RH to 70% RH at 25 ° C. Board.   It is packaged in a bag subjected to moisture-proofing treatment, and the humidity in the packaged state is a difference within 15% RH with respect to the humidity when the polarizing plate is bonded to the liquid crystal panel. Item 27. The polarizing plate according to any one of Items 22 to 26.   An OCB mode liquid crystal display comprising at least one of the optical cellulose acylate film according to any one of claims 1 to 21 and the polarizing plate according to any one of claims 22 to 27. apparatus.   A VA mode liquid crystal display comprising at least one of the optical cellulose acylate film according to any one of claims 1 to 21 and the polarizing plate according to any one of claims 22 to 27. apparatus.   30. Only one of the optical cellulose acylate film according to any one of claims 1 to 21 or the polarizing plate according to any one of claims 22 to 27 is used. VA mode liquid crystal display device of description.   The optical cellulose acylate film according to any one of claims 1 to 21 or the polarizing plate according to any one of claims 22 to 27 is used on a backlight side. Item 33. The VA mode liquid crystal display device according to item 29 or 30.

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