JP2007254699A - Polymer film and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal-displaying device excellent in displaying grace by decreasing the unevenness of membrane thickness of a phase difference film. <P>SOLUTION: This polymer film is characterized by having ≤1 μm maximum difference of height (P-V value) of the membrane thickness within a range of 60 mm diameter by taking an optional point in the film as a center, ≤0.15 μm RMS (root mean square) value of the membrane thickness or ≤0.40° difference of the maximum value and minimum vale of orienting angle within a 60 mm×60 mm square. The method for producing the same, a polarlizing plate by using the same and the liquid crystal-displaying device by using the polarlizing plate are also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polymer film and a method for producing the same.

Liquid crystal display devices are widely used for personal computer and portable device monitors and television applications due to various advantages such as low voltage, low power consumption, and being capable of being reduced in size and thickness. 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, and fixing the optical compensation sheet to a TN mode liquid crystal cell to widen the viewing angle. . However, a liquid crystal display device for television that is expected to be viewed from various angles on a large screen has a strict requirement for viewing angle dependency, and even with the above-described method, the requirement cannot be satisfied. Therefore, liquid crystal display devices different from the TN mode, such as an IPS (In-Plane Switching) mode, an OCB (Optically Compensatory Bend) mode, and a VA (Vertically Aligned) mode, have been studied. In particular, the VA mode is attracting attention as a liquid crystal display device for TV because of its high contrast and relatively high production yield.

Cellulose acetate films are generally 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.
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 1 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, but it is necessary to increase the birefringence by simultaneously orienting the additives in the stretching process. 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.

Patent Document 2 has an acyl group having 2 to 4 carbon atoms as a substituent, where the substitution degree of acetyl group is A and the substitution degree of propionyl group or butyryl group is B, formula 2.0 ≦ An optical film containing cellulose acylate that simultaneously satisfies A + B ≦ 3.0 and formula A <2.4, and further has a refractive index Nx in the slow axis direction and a refractive index Ny in the fast axis direction at a wavelength of 590 nm. An optical film characterized by satisfying the formula 0.0005 ≦ Nx−Ny ≦ 0.0050 is disclosed.
Further, Patent Document 3 discloses a polarizing plate used in a VA mode liquid crystal display device, the polarizing plate having a polarizer and an optically biaxial mixed fatty acid cellulose acylate film, and a liquid crystal cell and a polarizer. A polarizing plate is disclosed in which the optically biaxial mixed fatty acid cellulose acylate film is disposed between the two.

  The cellulose ester film is usually produced by a solution casting method. The solution casting method can produce a film having excellent physical properties such as optical properties as compared with other production methods such as a melt casting method. In the solution casting method, a polymer solution (hereinafter referred to as a dope) is prepared by dissolving a polymer in a mixed solvent containing dichloromethane or methyl acetate as a main solvent. The dope is cast on a support by forming a casting bead from a casting die to form a casting film. After the cast film has a self-supporting property on the support, it is peeled off from the support as a film (hereinafter, this film is referred to as a wet film), dried and wound up as a film (for example, (Refer nonpatent literature 1.).

In the solution casting method, drying air is applied to the surface in order to advance the drying of the cast film. However, when the cast film is dried rapidly, the surface shape may be deteriorated. Therefore, a method is known in which the drying rate of the cast film is set to 300% by mass / min (= 5% by mass / s) or less in terms of the amount of solvent contained on a dry basis, and the drying is performed gently (for example, Patent Document 4). reference.). A co-casting method in which the cast film has a multilayer structure is also known. For example, a cast film that forms skin layers (skin layers) on both surfaces of the core layer, which is an intermediate layer, may be mentioned. In this case, the dope viscosity of the core layer is increased to ensure the strength of the cast film, and the dope viscosity for forming the skin layer is lowered to improve the surface smoothness (for example, patents). Reference 5).
European Patent Application No. 91656 JP 2002-71957 A JP 2003-270442 A JP-A-11-123732 JP 2003-276037 A Japan Society for Invention and Innovation Public Technical Bulletin No. 2001-1745

  The method disclosed in the above-mentioned document is effective in that an inexpensive and thin liquid crystal display device can be obtained. However, in a liquid crystal display device that imparts high retardation to the cellulose ester film and is used as a retardation film, slight thickness unevenness is also visually recognized. Furthermore, in a liquid crystal display device for TV, the black luminance decreases with the recent increase in the contrast of the panel, and slight unevenness of the optical film is also visually recognized. Therefore, the required level of film flatness is also increasing. On the other hand, under the conventional film forming conditions, there are problems that streaks and stagnation unevenness and unevenness observed during crossed Nicols occur due to the wind speed during drying. The unevenness generated at the time of drying is a serious problem particularly in the case of an optical film that requires excellent flatness. Furthermore, in order to increase the productivity of the film, the casting speed is increased and the drying speed is increased. In this case, in the method described in Patent Document 4, since the drying speed is reduced, there is a problem in that the productivity of the film is reduced. Further, the method described in Patent Document 5 always requires multi-layer casting, which may result in a production method that is not suitable for a desired film.

  The objective of this invention is providing the liquid crystal display device excellent in the display quality by reducing the film thickness nonuniformity of a phase difference film in the liquid crystal display device which uses a cellulose-ester film as a phase difference film.

  As a result of intensive studies by the present inventors, a film (hereinafter referred to as an initial film) is formed on the surface of the cast film by rapidly drying the cast film in the hot air drying zone within 15 seconds from the start of casting. It was found that the growth of the film was promoted while the surface shape of the initial film was smoothed by the leveling effect. Moreover, it discovered that the film obtained by extending | stretching and drying this cast film was excellent in planarity. Furthermore, by using the polymer film thus adjusted so that the maximum height difference (PV value) of the film thickness is 1 μm or less and the orientation angle distribution is adjusted to 0.40 degrees or less, The inventors have found that the object can be achieved and have completed the present invention.

  That is, the present invention is a polymer film having the following constitution, a solution casting method, a polarizing plate and a liquid crystal display device using the cellulose ester film, and thereby the above-described object of the present invention is achieved.

(1) A polymer film characterized by having a maximum difference in film thickness within a range of 60 mm in diameter with respect to an arbitrary point in the film as 1 μm or less.
(2) A polymer film characterized by having an RMS value of a film thickness in a range of 60 mm in diameter from 0 μm to 0.15 μm centering on an arbitrary point in the film.

(3) A polymer film characterized in that a difference between a maximum value and a minimum value of an orientation angle in any 60 mm × 60 mm square in the film is 0 degree to 0.40 degree.
(4) The polymer film as described in (1) or (2) above, wherein the difference between the maximum value and the minimum value of the orientation angle in any 60 mm × 60 mm square in the film is 0 degree to 0.40 degree .

(5) The front retardation Re ₍ λ ₎ is 0 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm, and the retardation Rth ₍ λ _{) in} the film thickness direction is 60 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm (1) -(4) The polymer film in any one.
Here, Re ₍ λ ₎ is the front retardation (Re) value (unit: nm) at the wavelength λnm, and Rth ₍ λ ₎ is the retardation (Rth) value (unit: nm) in the film thickness direction at the wavelength λnm.

(6) The polymer 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 polymer 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) The polymer film as described in any one of (1) to (7) above, wherein the film thickness is 40 to 180 μm.

(9) The polymer film according to any one of (1) to (8), wherein the polymer film is a cyclic polyolefin.
(10) The above polymer film characterized in that the raw material polymer of the polymer film is a cellulose ester, the acyl substituent consists essentially of an acetyl group, and the total substitution degree is 2.56 to 3.00. The polymer film according to any one of 1) to (8).

(11) The acyl substituent is substantially composed of at least two kinds of an acetyl group, a propionyl group, and a butanoyl group, and the total degree of substitution is 2.50 to 3.00 (1) to (8) ) The cellulose ester film according to any one of
(12) A film comprising cellulose acylate obtained by substituting a hydroxyl group of a glucose unit constituting cellulose with an acyl group having 2 or more carbon atoms, and depending on the acyl group of the hydroxyl group at the 2-position of the glucose unit When the substitution degree is DS2, the substitution degree of the hydroxyl group at the 3-position with an acyl group is DS3, and the substitution degree with the acyl group of the hydroxyl group at the 6-position is DS6, the following formulas (I) and (II) are satisfied: The cellulose ester film according to (10).
(I): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
(II): DS6 / (DS2 + DS3 + DS6) ≧ 0.315

(13) A dope containing a polymer and a solvent is cast on a support that runs endlessly from a casting die, a cast film is formed from the dope on the support, and the dope is flowed to the support. A solution casting method comprising a step of applying a dry air of 3 m / s or more to a casting membrane from within 15 seconds after stretching, and a step of peeling the casting membrane as a film, wherein the casting membrane is removed from the support. A solution casting method, comprising a step of stretching the film after peeling as a film.

(14) A dope containing a polymer and a solvent is cast on a support that runs endlessly from a casting die, a cast film is formed from the dope on the support, and the cast film is peeled off as a film. In the solution casting method, an initial film serving as a film formation start film is formed on the surface of the casting film, and the surface shape of the casting film surface is smoothed by a leveling effect of the initial film. A solution casting method comprising: a step of stretching the film after peeling the casting membrane from the support as a film.

(15) The solution casting method according to (14), wherein the initial film is formed by applying dry air to the casting film.
(16) Before the drying wind hits the casting film, the wind drifting on the casting film surface is less than 3 m / s in wind speed, and the time for which the wind drifts is 15 seconds or less. The solution casting method according to any one of (13) to (15).
(17) The solution casting method according to any one of (13) to (16), wherein the wind speed of the dry air is 3 m / s or more and 15 m / s or less.

(18) The solution casting method according to any one of (13) to (17), wherein the dry air is applied to the casting film for 20 seconds or more.
(19) The solution casting method according to any one of (13) to (18), wherein a gas concentration of the dry air is 25% or less.
(20) The solution casting method according to any one of (13) to (19), wherein the temperature of the drying air is 40 ° C. or higher and 150 ° C. or lower.

(21) The above-mentioned (13) to (20), wherein the organic solvent in the polymer solution before film formation (hereinafter referred to as dope) contains 0.1% by mass or more and 40% by mass or less alcohol having 6 or less carbon atoms. The solution casting method according to any one of the above.

(22) In the solution casting method described above, at least two layers of an inner layer and an outer layer are cast by co-casting, and the solid content concentration of the outer layer is 1 than the solid concentration of the inner layer dope. solution casting method according to any one of (13) to (21), wherein the above mass% is a low concentration.

(23) In the solution casting method, at least two layers of an inner layer and an outer layer are cast by co-casting, and the amount of alcohol added to the outer layer is 1.05 to 6. The solution casting method according to any one of (13) to (22), wherein the solution casting method is 0 times.
(24) A film forming method in which at least two layers of an inner layer and an outer layer are cast by co-casting, wherein the amount of matting agent fine particles added to the inner layer is lower than that of the outer layer dope (13) to (23) The solution casting method according to any one of (23).

(25) The solution casting method as described in any one of (13) to (24) above, wherein the draw ratio is 1.01 to 2.0.

(26) The polymer film according to any one of (1) to (12), which is produced by the solution casting method according to any one of (13) to (25).
(27) A polymer film comprising an optical compensation layer on the polymer film according to any one of (1) to (12) and (26).
(28) The polymer film according to (27), wherein the optical compensation layer is a discotic liquid crystalline compound.

(29) A polarizing plate using at least one of the polymer films according to any one of (1) to (12) and (26) to (28) as a protective film for a polarizer.
(30) The structure described in (29) above, wherein at least one 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. Polarizer.

(31) At least one of the polymer film according to any one of (1) to (12) and (26) to (28) and the polarizing plate according to (29) or (30) is used. A liquid crystal display device characterized by the above.

According to the solution casting method of the present invention, a dope containing a polymer and a solvent is cast on a support that runs endlessly from a casting die, and a casting film is formed from the dope on the support. In the solution casting method in which the casting film is peeled off as a film, the drying film is blown from the air blowing port within 15 seconds after the casting film is formed on the support, without using special equipment. In addition, a film with improved planarity can be produced without reducing the film forming speed.
Moreover, according to the cellulose ester film of the present invention, an optical film with little display unevenness can be provided when used in a liquid crystal display device.

Hereinafter, the present invention will be described in detail.
The present invention has a maximum height difference (PV value) of 1 μm or less and a RMS value of film thickness of 0.15 μm or less, with an arbitrary point in the film as the center, within a diameter of 60 mm. The present invention relates to a polymer film characterized in that the difference between the maximum value and the minimum value of the orientation angle distribution is 0.40 degrees or less.

The maximum height difference (PV value) of the film thickness was measured with a FUJINON fringe analyzer (FX-03). At this time, the measurement area was in the range of diameter φ = 60 mm. As the refractive index value to be input, an average refractive index of 1.48 of cellulose acylate or an average refractive index of 1.53 of cycloolefin polymer was used. The resolution of this apparatus is 512 × 512.
The maximum height difference (P-V value) of the film thickness can be measured by a method other than using the FUJINON fringe analyzer (FX-03). For example, a film thickness within a range of 60 mm in diameter with an arbitrary point in the film as the center can be measured using a laser displacement meter, a contact-type film thickness meter, etc., and the maximum height difference can be obtained.

    The RMS value of the film thickness is a value defined by the following formula, and was measured by a FUJINON fringe analyzer (FX-03) in the same manner as the PV value.

  The RMS value can also be obtained using other devices such as a laser displacement meter and a contact-type film thickness meter. In this case, the film thickness is measured using a laser displacement meter, a contact-type film thickness meter, or the like for at least 200 points within a diameter of 60 mm around an arbitrary point in the film, and an average value of the film thickness is obtained. Next, the RMS value can be obtained by calculating the difference between the average value of the film thickness and the film thickness at each measurement point, obtaining Δdi, and applying this to the above equation.

  A preferable range of the PV value of the film thickness thus measured is 1 μm or less, more preferably 0.8 μm or less, still more preferably 0.6 μm or less, and most preferably 0.8 μm or less. 4 μm or less.

  A preferable range of the RMS value of the film thickness is 0.15 μm or less, more preferably 0.10 μm or less, still more preferably 0.07 μm or less, and most preferably 0.04 μm or less. As described above, the film having excellent flatness is less likely to cause unevenness when the polarizing plates are bonded to each other, and can provide a panel without unevenness.

  The orientation angle distribution of the polymer film was measured by OPTIPRO (XY scanning stage, halogen lamp light + 550 nm interference filter). At this time, the measurement area was 60 mm × 60 mm, and measurement was performed at intervals of 4 mm using a beam with a diameter of 3 mm.

  A preferable range of the difference between the maximum value and the minimum value of the orientation angle distribution in the range of 60 mm × 60 mm measured in this way is 0.40 degrees or less, more preferably 0.30 degrees or less, More preferably, it is 0.20 degree or less, Most preferably, it is 0.10 degree or less. As described above, the film with improved orientation angle distribution in the minute region can remarkably improve the unevenness at the time of crossed Nicol observation, and can provide a panel without unevenness.

  In the present invention, the “orientation angle” does not refer to the angle between the orientation direction of the polymer film and a specific direction in the film plane. However, in the case of “difference between the maximum value and the minimum value of the orientation angle”, an arbitrary but common direction is used as a reference, and the difference between the maximum value and the minimum value of the angle formed by this and the orientation direction of the polymer film is calculated. Since it points to it, the value can be determined uniquely.

  The present invention also relates to the following solution casting method. Casting a dope containing a polymer and a solvent from a casting die onto a support that runs endlessly, forming a casting film from the dope on the support, and stripping the casting film as a film In the membrane method, dry air is applied to the cast membrane. And / or forming an initial film on the surface of the casting film as an initial film for forming the film, and due to the leveling effect of the initial film, the surface shape of the surface of the casting film, preferably the film after production is the above Smoothing so as to fall within the range of PV value, RMS value and orientation angle. This cast film is peeled off and stretched in some cases.

The latter process is as follows. For example, a film (hereinafter referred to as an initial film) is formed on the surface of the cast film by rapidly drying the cast film in a hot air drying zone within 15 seconds from the start of casting. The film growth is promoted while the shape is smoothed.
The initial film refers to a cast film bulk or a layer of volatile matter that is relatively lower than the volatile content on the support surface side.
As a result, for example, a film having a maximum height difference (P-V value) of 1 μm or less within a range of 60 mm in diameter around an arbitrary point in the film can be produced.

Although the solution casting method will be described in detail later, a preferred embodiment of the present invention will be described here.
The initial film is preferably formed by applying dry air to the casting film. Before the dry air hits the casting membrane, it is preferable that the time that the wind of less than 3 m / s floats on the surface of the casting membrane is 15 seconds or less, more preferably 10 seconds or less, most preferably 7 seconds or less.
The wind speed of the dry air is preferably 3 m / s or more and 15 m / s or less, more preferably 4 m / s or more and 12 m / s or less, and most preferably 4 m / s or more and 10 m / s or less.
The time for applying the dry air to the cast film is preferably 20 seconds or more.
The time for which the dry air is applied to the casting film is preferably not more than the time when the volatile solvent component is not problematic for casting film peeling (preferably 20% by mass or more), and depends on the drying conditions. Usually, 10 minutes or less is preferable.
The gas concentration of the dry air is preferably 25% or less, more preferably 20% or less, and most preferably 18% or less. In the present invention, the gas concentration means a volatile solvent component in dry air measured by infrared analysis.
The temperature of the drying air is preferably 40 ° C. or higher and 150 ° C. or lower, more preferably 45 ° C. or higher and 120 ° C. or lower, and most preferably 50 ° C. or higher and 100 ° C. or lower.
It is preferable that the drying air is applied to the surface of the casting film by a slit nozzle or a two-dimensional nozzle.
The drying is preferably performed in a nitrogen atmosphere. The relative humidity at this time is preferably 10% or less, more preferably 5% or less, and particularly preferably 1% or less.

The initial membrane preferably starts to be formed within 15 seconds after the casting membrane is formed on the support, more preferably within 10 seconds, and most preferably within 7 seconds.
The residual solvent amount of the cast film when starting the drying of the surface of the cast film is preferably 200% by mass or more and 500% by mass or less, and 250% by mass or more and 450% by mass or less based on the dry weight. More preferably, it is 300 mass% or more and 420 mass% or less.

The decrease rate of the solvent contained in the cast film for 30 seconds after supplying the drying air is preferably 1% by mass / s or more and 15% by mass / s or less based on the dry weight. It is more preferable that it is / s or more and 12 mass% / s or less, and it is further more preferable that they are 5 mass% / s or more and 10 mass% / s or less.
The viscosity at the time of casting of the dope is preferably 10 Pa · s or more and 100 Pa · s or less, more preferably 12 Pa · s or more and 50 Pa · s or less, and most preferably 15 Pa · s or more and 40 Pa · s or less. is there.

The casting is preferably performed by co-casting.
It is preferable that at least one of the thickness of the layer on the air surface side and the thickness of the layer on the support side is 0.5% to 30% of the thickness of the entire film in the film composed of multiple layers by co-casting.
When performing a co-casting, solid concentration of the dope of the outer layer, it is preferably a low concentration of 1 mass% or more than the solid concentration of the inner layer of doped, is 3 mass% or more lower concentration Further preferred. In addition, it is preferable that the dope contacting the outside world has a larger alcohol composition ratio than the internal dope. The amount of the dope alcohol added to the outer layer is preferably 1.05 to 6.0 times, more preferably 1.2 to 4.0 times, and more preferably 1.5 to 3.0 times that of the inner layer. It is particularly preferred that
The running speed of the support is preferably 10 m / min or more and 200 m / min or less, more preferably 15 m / min or more and 150 m / min or less, and further preferably 20 m / min or more and 120 m / min or less. preferable.

  Next, the polymer material preferably used in the present invention will be specifically described below.

[Material of polymer film]
As a material for forming the polymer film of the present invention, a polymer excellent in optical transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, and the like is preferable, and any material may be used. Examples thereof include polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, acrylic polymers such as polymethyl methacrylate, and styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin). Polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers , Polyether ether ketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl alcohol polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, or polymers mixed with the above polymers Take an example. The polymer film of the present invention can also be formed as a cured layer of an ultraviolet-curable or thermosetting resin such as acrylic, urethane, acrylic urethane, epoxy, or silicone. In addition, as a material for forming the polymer film of the present invention, a thermoplastic norbornene resin can be preferably used. Examples of the thermoplastic norbornene-based resin include ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., and ARTON manufactured by JSR Corporation.

  Further, as a material for forming the polymer film of the present invention, a cellulose polymer (hereinafter referred to as cellulose acylate) represented by triacetyl cellulose, which has been conventionally used as a transparent protective film for polarizing plates, is preferably used. I can do it. Details of the cellulose acylate will be described below.

Next, the cellulose ester film preferably used in the present invention 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 ester is a polymer obtained by esterifying some or all of these hydroxyl groups with a substituent having 2 or more carbon atoms. The substituent is preferably an acyl group. The degree of substitution means the ratio at which the hydroxyl group of cellulose is esterified at each of the 2-position, 3-position and 6-position (100% esterification has a degree of substitution of 1).
The total acyl substitution degree, that is, DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.20 to 2.90, and particularly preferably 2.55 to 2.85. Further, DS6 / (DS2 + DS3 + DS6) is preferably 0.310 or more, and particularly preferably 0.315 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 ester 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 preferably 2.00 to 3.00, more preferably 2.20 to 2.90, and particularly preferably 2.55 to 2.85. Further, DSB is 1.70 or less, and particularly preferably 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 ester 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.

  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, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst.
In order to obtain the cellulose acylate, specifically, a cellulose raw material such as cotton linter or wood pulp is pretreated with an appropriate amount of acetic acid, and is then esterified by introducing it into a pre-cooled carboxylated mixed solution. Synthesize the rate (the sum of the acyl substitution degree at the 2nd, 3rd and 6th positions is approximately 3.00). The carboxylated mixed solution generally contains acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. The carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system. After completion of the esterification reaction, a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc) is used for hydrolysis of excess carboxylic anhydride remaining in the system and neutralization of a part of the esterification catalyst. Of carbonate, acetate or oxide). Next, the obtained complete cellulose acylate is saponified and aged by maintaining it at 50 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain 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 to the cellulose acylate solution), the cellulose acylate is separated, washed and stabilized, and the like. Can be obtained.

In the cellulose acylate film, it is preferable that a polymer component constituting the film is substantially composed of the specific cellulose acylate. “Substantially” means 55% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more) of the polymer component.
The cellulose acylate is preferably used in the form of particles. 90% by mass or more of the particles to be used preferably have a particle diameter of 0.5 to 5 mm. Moreover, it is preferable that 50 mass% or more of the particle | grains to be used have a particle diameter of 1-4 mm. The cellulose acylate particles preferably have a shape as close to a sphere as possible.
The degree of polymerization of cellulose acylate preferably used in the present invention is a viscosity average degree of polymerization, preferably 200 to 700, more preferably 250 to 550, still more preferably 250 to 400, and particularly preferably 250 to 350. . The average degree of polymerization can be measured by Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Society, Vol. 18, No. 1, pages 105-120, 1962). Further details are described in JP-A-9-95538.

When the low molecular component is removed, the average molecular weight (polymerization degree) is increased, but the viscosity is lower than that of ordinary cellulose acylate. Therefore, the cellulose acylate from which the low molecular component is removed is useful. . Cellulose acylate having a small amount of low molecular components can be obtained by removing low molecular components from cellulose acylate synthesized by a usual method. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent. In addition, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose acylates. When the amount of the sulfuric acid catalyst is within the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized. When used in the production of cellulose acylate, the water content is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly 0.7% by mass or less. In general, cellulose acylate contains water and is known to have a water content of 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 page 7 to page 12 of the raw material cotton and the synthesis method in the Japan Society of Invention and Innovation Technical Bulletin No. 2001-1745 (issued March 15, 2001, Japan Society of Invention and Innovation). It is described in.

The optical property Re retardation value and Rth retardation value of the cellulose ester film of the present invention satisfy the following formulas (V) and (VI), respectively.
(V): 5 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
(VI): 60 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm

More preferably, the following formulas (VII) and (VIII) are satisfied.
(VII): 20 nm ≦ Re ₍₅₉₀₎ ≦ 100 nm
(VIII): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 300 nm

In the present specification, Re _(λ) and Rth _(λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. Re _(λ) is measured in KOBRA 21ADH (manufactured by Oji Scientific Instruments) by making light having a wavelength of λ nm incident in the normal direction of the film. Rth _(λ) is Re _(λ) , light having a wavelength of λ nm from a direction inclined by + 40 ° with respect to the film normal direction with an in-plane slow axis (determined by KOBRA 21ADH) as an inclination axis (rotation axis). And a retardation value measured by injecting light having a wavelength of λ nm from a direction tilted by −40 ° with respect to the normal direction of the film with the in-plane slow axis as the tilt axis (rotation axis). KOBRA 21ADH calculates based on the retardation value measured in a total of three directions, the assumed value of the average refractive index, and the input film thickness value. Here, as the assumed value of the average refractive index, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−nz) is further calculated from the calculated nx, ny, and nz. These measurements were performed in an environment of 25 ° C. and 60% RH unless otherwise specified.

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

<Additives>
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.

<Retardation expression agent>
In the present invention, it is preferable to use a retardation developer in order to develop a preferable retardation value. Examples of the retardation enhancer that can be used in the present invention include those composed of rod-like or discotic compounds. As the rod-like or discotic compound, a compound having at least two aromatic rings can be used.
The addition amount of the retardation developer composed of a rod-shaped compound is preferably 0.1 to 30 parts by mass, and preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. Further preferred.
The disk-shaped retardation developer is preferably used in a range of 0.05 to 20 parts by mass, and in a range of 1.0 to 15 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. It is more preferable to use, and it is still more preferable to use in the range of 3.0-10 mass parts.
Since the discotic compound is superior to the rod-like compound in Rth retardation expression, it is preferably used when a particularly large Rth retardation is required.
Two or more retardation developing agents may be used in combination.
The retardation developer composed of a rod-like or discotic compound preferably has maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

The discotic compound will be described. As the discotic compound, a compound having at least two aromatic rings can be used.
In the present specification, the “aromatic ring” includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring.

The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).
The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

  As the aromatic ring, benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferable, In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, a compound disclosed in JP-A-2001-166144 is preferably used as the discotic compound.

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

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

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

  The linking group in (c) is also preferably bonded to carbon atoms of two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof. Examples of linking groups consisting of combinations are shown below. In addition, the relationship between the left and right in the following examples of the linking group may be reversed.

c1: -CO-O-
c2: —CO—NH—
c3: -alkylene-O-
c4: —NH—CO—NH—
c5: —NH—CO—O—
c6: —O—CO—O—
c7: -O-alkylene-O-
c8: -CO-alkenylene-
c9: -CO-alkenylene-NH-
c10: -CO-alkenylene-O-
c11: -alkylene-CO-O-alkylene-O-CO-alkylene-
c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-
c13: -O-CO-alkylene-CO-O-
c14: -NH-CO-alkenylene-
c15: -O-CO-alkenylene-

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

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

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

The alkylthio group preferably has 1 to 12 carbon atoms. Examples of the alkylthio group include a methylthio group, an ethylthio group, and an octylthio group.
The alkylsulfonyl group preferably has 1 to 8 carbon atoms. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.
The number of carbon atoms in the aliphatic amide group is preferably 1-10. Examples of the aliphatic amide group include an acetamide group.
The number of carbon atoms of the aliphatic sulfonamide group is preferably 1-8. Examples of the aliphatic sulfonamido group include a methanesulfonamido group, a butanesulfonamido group, and an n-octanesulfonamido group.
The number of carbon atoms of the aliphatic substituted amino group is preferably 1-10. Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group, and a 2-carboxyethylamino group.

The number of carbon atoms in the aliphatic substituted carbamoyl group is preferably 2-10. Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.
The number of carbon atoms in the aliphatic substituted sulfamoyl group is preferably 1-8. Examples of the aliphatic substituted sulfamoyl group include a methylsulfamoyl group and a diethylsulfamoyl group.
The number of carbon atoms in the aliphatic substituted ureido group is preferably 2-10. Examples of the aliphatic substituted ureido group include a methylureido group.
Examples of the non-aromatic heterocyclic group include a piperidino group and a morpholino group.
The molecular weight of the retardation developer composed of a discotic compound is preferably 300 to 800.

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

  As the rod-shaped compound, those having at least two aromatic rings are preferable, and as the rod-shaped compound having at least two aromatic rings, a compound represented by the following general formula (1) is preferable.

Formula (1): Ar ¹ -L ¹ -Ar ²

In the general formula (1), Ar ¹ and Ar ² are each independently an aromatic group.
In the present specification, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.

An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. The heterocycle of the aromatic heterocyclic group is generally unsaturated. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As a hetero atom, a nitrogen atom, an oxygen atom or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.
As the aromatic ring of the aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring are preferable, and a benzene ring is particularly preferable. .

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

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

In the general formula (1), L ¹ is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, —O—, —CO—, and a combination thereof.
The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As the chain alkylene group, a linear alkylene group is more preferable than a branched alkylene group.
The alkylene group preferably has 1 to 20 carbon atoms, more preferably 1 to 15, more preferably 1 to 10, still more preferably 1 to 8, and most preferably 1 to 6. 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 alkenylene group and the alkynylene group preferably have 2 to 10 carbon atoms, more preferably 2 to 8, more preferably 2 to 6, still more preferably 2 to 4, and most preferably 2. (Vinylene or ethynylene).
The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.

In the molecular structure of the general formula (1), the angle formed by Ar ¹ and Ar ² across L ¹ is preferably 140 degrees or more.
As the rod-like compound, a compound represented by the following formula (2) is more preferable.

Formula ^{(2): Ar 1 -L 2} -X-L 3 -Ar 2

In the general formula (2), Ar ¹ and Ar ² are each independently an aromatic group. The definition and examples of the aromatic group are the same as those of Ar ¹ and Ar ^{2 in} the general formula (1).

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

  Specific examples of the compound represented by the general formula (1) or (2) are shown below.

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

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

Other preferred compounds are shown below.

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

<Plasticizer>
The plasticizer is preferably a phosphate ester or a carboxylic acid ester. The plasticizer may be triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, dimethyl phthalate (DMP), diethyl Phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP), diethyl hexyl phthalate (DEHP), triethyl O-acetylcitrate (OACTE), tributyl O-acetylcitrate (OACTB), Acetyl triethyl citrate, acetyl tributyl citrate, butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate, triacetin, Buchirin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and more preferably one selected from butyl phthalyl butyl glycolate. Furthermore, the plasticizer is preferably (di) pentaerythritol esters, glycerol esters, diglycerol esters.

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

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

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

  0.001-5 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of a ultraviolet absorber, 0.01-1 mass% is more preferable. 0.001 mass% or more is preferable at the point which can fully exhibit the addition effect, and 5 mass% or less is preferable at the point which can suppress the bleed-out of the ultraviolet absorber to the film surface.

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

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

<Peeling accelerator>
Examples of the peeling accelerator include citric acid ethyl esters. Furthermore, infrared absorbers are described, for example, in JP-A No. 2001-194522.
These additives may be added at any time in the dope preparation step, but may be added to the final preparation step of the dope preparation step by adding a preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, and these are conventionally known techniques. The glass transition point Tg measured with a dynamic viscoelasticity measuring device for cellulose acylate film (Vibron: DVA-225 (ITG Measurement & Control Co., Ltd.)) is determined at 70 to 150 ° C. In addition, it is preferable that the elastic modulus measured with a tensile tester (Strograph-R2 (Toyo Seiki)) is 1500 to 4000 MPa. More preferably, the glass transition point Tg is 80 to 135 ° C. and the elastic modulus is 1500 to 3000 MPa. That is, the cellulose ester film of the present invention preferably has a glass transition point Tg and an elastic modulus within the above ranges from the viewpoint of process suitability for polarizing plate processing and liquid crystal display device assembly.
Furthermore, regarding the additive, the Japan Institute of Invention and Innovation Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Japan Institute of Invention) p. Those described in detail after 16 can be used as appropriate.

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

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

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

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

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

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

Next, the organic solvent in which the cellulose ester of the present invention is dissolved will be described.
In the present invention, any of a chlorinated solvent containing a chlorinated organic solvent as a main solvent and a non-chlorinated solvent not containing a chlorinated organic solvent can be used as the organic solvent.

<Chlorine solvent>
In preparing the cellulose ester solution of the present invention, a chlorinated organic solvent is preferably used as the main solvent. In the present invention, the type of the chlorinated organic solvent is not particularly limited as long as the object can be achieved within the range in which cellulose acylate can be dissolved and cast and formed. These chlorinated organic solvents are preferably dichloromethane and chloroform. Particularly preferred is dichloromethane. In addition, there is no particular problem in mixing an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50% by mass of dichloromethane in the total amount of the organic solvent. Other organic solvents used in combination with the chlorinated organic solvent in the present invention will be described below. That is, as another preferable organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Esters, ketones, ethers and alcohols may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a solvent. 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 the 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. Moreover, it is preferable that the carbon number contained in alcohol is 6 or less. 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. Of these, methanol, ethanol, propanol and butanol are preferably used. The alcohol contained in the organic solvent is preferably 0.1% by mass to 40% by mass, more preferably 10% by mass to 30% by mass, and further preferably 20% by mass to 30% by mass. Most preferred.

In addition, both aromatic hydrocarbons and aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.
Examples of combinations of chlorinated organic solvents and other organic solvents include the following compositions, but are not limited thereto.

Dichloromethane / methanol (87/13, parts by mass),
Dichloromethane / methanol (75/25, parts by mass),
Dichloromethane / ethanol (90/10, parts by mass),
Dichloromethane / ethanol (80/20, parts by mass),
Dichloromethane / propanol (90/10, parts by mass),
Dichloromethane / propanol (85/15, parts by mass),
Dichloromethane / butanol (95/5, parts by mass),
Dichloromethane / butanol (80/20, parts by mass),
Dichloromethane / methanol / ethanol / butanol (80/10/5/5, parts by mass),
Dichloromethane / methanol / propanol (80/10/10, parts by mass),
Dichloromethane / methanol / butanol (80/15/5, parts by mass),
Dichloromethane / methanol / ethanol (80/10/10, parts by mass),
Dichloromethane / ethanol / butanol (85/10/5, parts by mass),
Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (75/10/10/5/7, parts by mass),
Dichloromethane / cyclopentanone / methanol / isopropanol (80/10/5/8, parts by mass)
Dichloromethane / methyl acetate / butanol (80/10/10, parts by mass),
Dichloromethane / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass)
Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),
・ Dichloromethane / 1, 3 dioxolane / methanol / ethanol (70/20/5/5, part by mass),
Dichloromethane / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),
Dichloromethane / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass),
・ Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (70/10/10/5/5, parts by mass),
Dichloromethane / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),
Dichloromethane / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),
Dichloromethane / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),
And so on.

<Non-chlorine solvent>
Next, the non-chlorine organic solvent preferably used for preparing the cellulose ester 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, cast, and formed into a film. The non-chlorine organic solvent used in the present invention is preferably a solvent selected from esters, ketones and ethers having 3 to 12 carbon atoms. Esters, ketones and ethers may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a main solvent, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The non-chlorine organic solvent used in the above cellulose acylate is selected from the various viewpoints described above, and is preferably as follows. That is, the non-chlorine solvent is preferably a mixed solvent containing the non-chlorine organic solvent as a main solvent, and is a mixed solvent of three or more different solvents, wherein the first solvent is methyl acetate, ethyl acetate, At least one selected from methyl formate, ethyl formate, acetone, dioxolane, and dioxane, or a mixture thereof; the second solvent is selected from ketones having 4 to 7 carbon atoms or acetoacetate; The solvent is a mixed solvent selected from alcohols or hydrocarbons having 1 to 10 carbon atoms, more preferably alcohols having 1 to 8 carbon atoms. Note that when the first solvent is a mixed liquid of two or more kinds of solvents, the second solvent may not be provided. The first solvent is more preferably methyl acetate, acetone, methyl formate, ethyl formate, or a mixture thereof, and the second solvent is preferably methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetyl acetate, or a mixed solvent thereof. It may be.

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

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

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

・ Methyl formate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, part by mass),
-Methyl formate / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass)
Acetone / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),
Acetone / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),
Acetone / 1,3-dioxolane / ethanol / butanol (65/20/10/5, parts by mass),
1,3-dioxolane / cyclohexanone / methyl ethyl ketone / methanol / butanol (55/20/10/5/5/5, parts by mass)
And so on.

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

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

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

Here, the definition of the associated molecular weight, the inertial square radius and the second virial coefficient in the present invention will be described. These are measured using the static light scattering method according to the following method. Although the measurement is performed in a dilute region for the convenience of the apparatus, these measured values reflect the behavior of the dope in the high concentration region of the present invention.
First, cellulose acylate is dissolved in a solvent used for the dope to prepare 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass% solutions. In order to prevent moisture absorption, the cellulose acylate is dried at 120 ° C. for 2 hours, and is measured at 25 ° C. and 10% RH. The dissolution method is carried out according to the method employed at the time of dope dissolution (room temperature dissolution method, cooling dissolution method, high temperature dissolution method). Subsequently, the solution and the solvent are filtered through a 0.2 μm Teflon filter. The filtered solution is measured for static light scattering 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 concentration gradient (dn / dc) uses the differential refractometer (Otsuka Electronics Co., Ltd. DRM-1021). Measure using the solvent and solution used for light scattering measurement.

<Dope manufacturing method>
Hereinafter, the method for producing a dope that is preferably used in the present invention will be described by way of example in which a cellulose ester is used as a polymer, but the present invention is not limited by this method. Moreover, when using it for the solution film-forming method of this invention, you may use another polymer.
First, a dope is manufactured using the above raw materials. First, the solvent is sent from the solvent tank to the dissolution tank. Next, the TAC contained in the hopper is fed into the dissolution tank while being measured. The required amount of the additive solution is fed from the additive tank to the dissolution tank. In addition to the method of sending the additive as a solution, for example, when the additive is liquid at room temperature, it can be sent to the dissolution tank in the liquid state. Further, when the additive is solid, a method of feeding into the dissolution tank using a hopper or the like is also possible. When a plurality of types of additives are added, a solution in which a plurality of types of additives are dissolved can be placed in the additive tank. Alternatively, a solution in which an additive is dissolved can be put in each of a plurality of additive tanks, and sent to the dissolution tank through independent pipes.

  In the above description, the order of putting into the dissolution tank is the solvent (used in the meaning including the case of the mixed solvent), TAC, and additive, but is not limited to this order. For example, a preferred amount of solvent can be fed after the TAC is metered into the dissolution tank. The additive does not necessarily need to be put in the dissolution tank in advance, and can be mixed in a mixture of TAC and a solvent (hereinafter, these mixtures may also be referred to as a dope) in a later step.

  The dissolution tank is provided with a jacket that wraps around its outer surface and a first stirrer that is rotated by a motor. Furthermore, it is preferable that the 2nd stirrer rotated by a motor is attached to the dissolution tank. The first stirrer is preferably provided with an anchor blade, and the second stirrer is preferably a dissolver type eccentric stirrer. Then, the temperature of the dissolution tank is adjusted by flowing a heat transfer medium between the dissolution tank and the jacket, and the preferred temperature range is -10 ° C to 55 ° C. By appropriately selecting and using the types of the first stirrer and the second stirrer, a swelling liquid in which TAC is swollen in a solvent is obtained.

  The swelling liquid is sent to the heating device by a pump. The heating device is preferably a jacketed pipe, and further preferably has a configuration capable of pressurizing the swelling liquid. By using such a heating apparatus, the dope is obtained by dissolving the solid content in the swelling liquid under heating conditions or under pressure heating conditions. Hereinafter, this method is referred to as a heating dissolution method. In this case, the temperature of the swelling liquid is preferably 50 ° C to 120 ° C. Moreover, the cooling dissolution method which cools a swelling liquid to the temperature of -100 degreeC--30 degreeC can also be performed. TAC can be sufficiently dissolved in a solvent by appropriately selecting the heating dissolution method and the cooling dissolution method. After the dope is brought to about room temperature with a temperature controller, the impurities contained in the dope are removed by filtration with a filtration device. The filtration filter used in the filtration device preferably has an average pore size of 100 μm or less. The filtration flow rate is preferably 50 L / hr or more. The dope 22 after filtration is sent to the stock tank 21 in the film production line 20 of FIG. 1 and stored therein.

  By the way, as described above, the method of once preparing the swelling liquid and then using the swelling liquid as a dope increases the time required as the concentration of TAC is increased, which may be problematic in terms of manufacturing cost. . In that case, it is preferable to prepare a dope having a concentration lower than the target concentration and then perform a concentration step for obtaining the target concentration. When using such a method, the dope filtered by the filtration device is sent to the flash device, and a part of the solvent in the dope is evaporated in the flash device. The solvent gas generated by the evaporation is condensed by a condenser (not shown) to become a liquid and recovered by a recovery device. The recovered solvent is regenerated and reused as a solvent for preparing a dope by a regenerator. This reuse is effective in terms of cost.

  Further, the concentrated dope is extracted from the flash device by a pump. Furthermore, it is preferable that a bubble removal process is performed to remove bubbles generated in the dope. As this defoaming method, various known methods are applied, for example, an ultrasonic irradiation method. The dope is then sent to a filtration device to remove foreign matter. In addition, it is preferable that the temperature of dope at the time of filtration is 0 degreeC-200 degreeC. The dope 22 is sent to the stock tank 21 and stored.

  By the above method, the dope whose TAC density | concentration is 5 mass%-40 mass% can be manufactured. More preferably, the TAC concentration is from 15% by mass to 30% by mass, and most preferably from 17% by mass to 25% by mass. The concentration of the additive (mainly a plasticizer) is preferably in the range of 1% by mass or more and 20% by mass or less when the total solid content in the dope is 100% by mass. In addition, from the [0517] paragraph of Japanese Patent Application No. 2004-264464 about the raw material in the solution casting method which obtains a TAC film, the raw material, the additive dissolution method and addition method, the filtration method, and the dope production methods such as defoaming [0616] The paragraph is detailed. These descriptions are also applicable to the present invention.

<Solution casting method>
Next, a method for producing a film using the dope 22 obtained above will be described. FIG. 1 is a schematic view showing a film production line 20. However, the present invention is not limited to the film production line as shown in FIG. The film production line 20 includes a stock tank 21, a filtration device 30, a casting die 31, a casting band 34 stretched around rotating rollers 32 and 33, a tenter dryer 35, and the like. In addition, an ear clip device 40, a drying chamber 41, a cooling chamber 42, a winding chamber 43, and the like are arranged.

  An agitator 61 that is rotated by a motor 60 is attached to the stock tank 21. The stock tank 41 is connected to the casting die 31 via the pump 62 and the filtration device 30.

  The material of the casting die 31 is preferably precipitation hardening type stainless steel, and its thermal expansion coefficient is preferably 2 × 10 −5 (° C. −1) or less. And what has corrosion resistance substantially equivalent to SUS316 in the forced corrosion test with the electrolyte aqueous solution can be used as the material of the casting die 31 and further immersed in a mixed solution of dichloromethane, methanol and water for 3 months. Even if it has corrosion resistance that does not cause pitting (perforation) at the gas-liquid interface, it is used. Furthermore, it is preferable to manufacture the casting die 31 by grinding a material that has passed one month or more after casting. As a result, the dope 22 flows uniformly in the casting die 31, and streaks are prevented from occurring in the casting film 69 described later. The finishing accuracy of the liquid contact surface of the casting die 31 is preferably 1 μm or less in terms of surface roughness, and the straightness is preferably 1 μm / m or less in any direction. The slit clearance of the casting die 31 can be adjusted in the range of 0.5 mm to 3.5 mm by automatic adjustment. About the corner | angular part of the liquid-contacting part of the lip | tip end of the casting die 31, the R shall be 50 micrometers or less over the whole width. Moreover, it is preferable that the shear rate in the casting die 31 is adjusted to be 1 (1 / sec) to 5000 (1 / sec).

  The width of the casting die 31 is not particularly limited, but is preferably 1.1 to 2.0 times the width of the film as the final product. Further, it is preferable to attach a temperature controller (not shown) to the casting die 31 so that the temperature during film formation is maintained at a predetermined temperature. The casting die 31 is preferably a coat hanger type. Further, it is more preferable that thickness adjusting bolts (heat bolts) are provided at predetermined intervals in the width direction of the casting die 31 and the casting die 31 is provided with an automatic thickness adjusting mechanism using a heat bolt. The heat bolt is preferably formed into a film by setting a profile according to the amount of pump 62 (preferably a high precision gear pump) according to a preset program. Further, feedback control may be performed by an adjustment program based on a profile of a thickness meter (for example, an infrared thickness meter) not shown in the film production line 20. The thickness difference between any two points in the width direction of the product film, excluding the casting edge portion, is adjusted within 1 μm, and the difference between the minimum value and the maximum value in the width direction thickness is adjusted to 3 μm or less. Preferably, adjusting to 2 μm or less is more preferable. Moreover, it is preferable to use the one whose thickness accuracy is adjusted to ± 1.5 μm or less.

  More preferably, a cured film is formed at the lip end of the casting die 31. A method for forming the cured film is not particularly limited, and examples thereof include ceramic coating, hard chrome plating, and a nitriding method. When ceramics are used as the cured film, it is preferable to use a ceramic that can be ground, has a low porosity, is not brittle, has good corrosion resistance, has good adhesion to the casting die 31, and does not have adhesion to the dope 22. Specific examples include tungsten carbide (WC), Al2O3, TiN, Cr2O3, etc. Among them, WC is particularly preferable. The WC coating can be performed by a thermal spraying method.

  In order to prevent the dope flowing out to the slit end of the casting die 31 from locally drying and solidifying, it is preferable to attach a solvent supply device (not shown) to the slit end. In this case, a solvent for solubilizing the dope (for example, a mixed solvent of 86.5 parts by mass of dichloromethane, 13 parts by mass of acetone, and 0.5 parts by mass of n-butanol) is used at both ends of the casting bead and at the end of the die slit. And it is preferable to supply to the periphery vicinity of the three-phase contact line which external air forms. Supplying at 0.1 mL / min to 1.0 mL / min to each one side of the end is preferable in order to prevent mixing of foreign matters into the cast film. In addition, as a pump which supplies this liquid, it is preferable to use a pump with a pulsation rate of 5% or less.

  A casting band 34 is provided below the casting die 31 so as to span the rotating rollers 32 and 33. The rotating rollers 32 and 33 are rotated by a driving device (not shown), and the casting band 34 travels endlessly with the rotation. The casting band 34 is preferably one that can move at a moving speed, that is, a casting speed of 10 m / min to 200 m / min, more preferably 15 m / min to 150 m / min, most preferably It is 20 m / min or more and 120 m / min or less. In view of film productivity, the casting speed is preferably 10 m / min or more. Moreover, 200 m / min or less is preferable at the point from which the casting bead is formed stably and the surface shape of the casting film 69 becomes favorable.

  Further, in order to set the surface temperature of the casting band 46 to a predetermined value, it is preferable that the heat transfer medium circulation device 63 is attached to the rotary rollers 32 and 33. The casting band 34 is preferably one whose surface temperature can be adjusted to -20 ° C to 40 ° C. A heat transfer medium flow path (not shown) is formed in the rotating rollers 32 and 33 used in the present embodiment, and the heat transfer medium maintained at a predetermined temperature passes through the flow path. The temperatures of the rotary rollers 32 and 33 are maintained at a predetermined value.

  The width of the casting band 34 is not particularly limited, but it is preferable to use a band having a range of 1.1 to 2.0 times the casting width of the dope 22. Further, it is preferable that the length is 20 m to 200 m, the thickness is 0.5 mm to 2.5 mm, and the surface roughness is polished to be 0.05 μm or less. The casting band 34 is preferably made of stainless steel, and more preferably made of SUS316 so as to have sufficient corrosion resistance and strength. Moreover, it is preferable to use the thickness unevenness of the entire casting band 34 of 0.5% or less.

It is also possible to use the rotating rollers 32 and 33 directly as a support. In this case, it is preferable that the rotation can be performed with high accuracy so that the rotation unevenness is 0.2 mm or less. In this case, it is preferable that the average roughness of the surfaces of the rotating rollers 32 and 33 is 0.01 μm or less. Therefore, the surface of the rotating roller is subjected to chrome plating or the like so as to have sufficient hardness and durability. In addition, it is necessary to suppress the surface defects of the support (the casting band 34 and the rotating rollers 32 and 33) to the minimum. Specifically, there is no pinhole of 30 μm or more, and the number of pinholes of 10 μm or more and less than 30 μm is 1 / m ² or less, and the number of pinholes of less than 10 μm is preferably ² / m ² or less.

  The casting die 31, the casting band 34 and the like are accommodated in the casting chamber 64. The casting chamber 64 is provided with a temperature control facility 65 for keeping the internal temperature at a predetermined value, and a condenser (condenser) 66 for condensing and recovering the volatile organic solvent. A recovery device 67 for recovering the condensed and liquefied organic solvent is provided outside the casting chamber 64. Further, it is preferable that a decompression chamber 68 for controlling the pressure of the back surface of the casting bead formed from the casting die 31 to the casting band 34 is disposed, and this is also used in this embodiment. .

  Air blowing ports 70, 71, 72 are provided near the peripheral surface of the casting band 34 in order to evaporate the solvent in the casting film 69. Further, as shown in FIG. 2, a labyrinth seal 50 is provided in the vicinity of the casting die 31 in order to suppress surface variation of the casting film 69 caused by blowing dry air to the casting film 69 immediately after casting. Is attached. Further, a quick drying air outlet (hereinafter referred to as a quick drying air outlet) 73 is provided between the labyrinth seal 50 and the air outlet 70. An air supply device 51 is attached to the quick drying air outlet 73 and the other air outlets 70 to 72. The quick-drying blower port 73 has a plurality of nozzles 73 a, and the drying film 57 is applied to the surface of the casting film 69 to form an initial film 69 a on the surface of the casting film 69. Although four nozzles provided in the quick drying air blowing port 73 are shown in FIG. 2, the present invention is not limited thereto. The distance between the labyrinth seal 50 and the quick drying air blowing port 73 is L1 (mm). This region is referred to as the “successful wind region A”. The length of the quick drying air blowing port 73 is L2 (mm). The decompression chamber 68 is connected to a decompression device (for example, a roots blower) 76. The time for which the drying air 57 is applied to the casting film 69 is preferably 20 seconds or longer. The air blowing time of the drying air 57 is preferably 20 seconds or more in that the formation of the initial film 69a proceeds and a film having an excellent surface shape can be obtained.

  As shown in FIG. 3, various modes of blowing air from the nozzle can be used. For example, as shown in FIG. 3A, there is one in which dry air is applied to the center of the casting film 69 from the nozzles 52 a and 52 b on both edges of the casting film 69. Moreover, as shown in (b), the nozzle 53 may be provided in the center part in the width direction of the casting film 69, and dry air may be applied to both edges from the said center part. Furthermore, as shown in (c), a dry air may be applied to the casting film 69 from the nozzle 54 of the casting film 69 toward the suction port 55. Further, the shape of the nozzle is not particularly limited.

  The crossover portion 80 is provided with a blower 81, and the ear-cutting device 40 downstream of the tenter dryer 35 is used for finely cutting the waste at the side end (referred to as an ear) of the cut film 82. Crusher 90 is connected.

  The drying chamber 41 is provided with a number of rollers 91, and an adsorption / recovery device 92 for adsorbing / recovering the solvent gas generated by evaporation is attached. In FIG. 1, the cooling chamber 42 is provided downstream of the drying chamber 41, but a humidity control chamber (not shown) may be provided between the drying chamber 41 and the cooling chamber 42. A forced static elimination device (static elimination bar) 93 for adjusting the charged voltage of the film 82 to a predetermined range (for example, −3 kV to +3 kV) is provided downstream of the cooling chamber 42. In FIG. 1, the forced static eliminating device 93 is illustrated on the downstream side of the cooling chamber 42, but is not limited to this installation position. Furthermore, in this embodiment, a knurling roller 94 for applying knurling to both edges of the film 82 by embossing is appropriately provided downstream of the forced static elimination device 93. Further, a winding roller 95 for winding the film 82 and a press roller 96 for controlling the tension at the time of winding are provided in the winding chamber 43.

  Next, an example of a method for producing the film 82 using the film production line 20 as described above will be described below. The dope 22 is always made uniform by the rotation of the stirrer 61. The dope 22 may be mixed with additives such as a plasticizer and an ultraviolet absorber even during the stirring.

  The dope 22 is sent to the filtration device 30 by the pump 62 and filtered there, and then is cast from the casting die 31 onto the casting band 34. The driving of the rotary rollers 32 and 33 is preferably adjusted so that the tension generated in the casting band 34 is 10 4 N / m to 10 5 N / m. Further, the relative speed difference between the casting band 34 and the rotating rollers 32 and 33 is adjusted to be 0.01 m / min or less. The speed fluctuation of the casting band 34 is preferably 0.5% or less, and the meandering in the width direction that occurs when the casting band 34 makes one rotation is preferably 1.5 mm or less. In order to control this meandering, a detector (not shown) for detecting the positions of both ends of the casting band 34 is provided, and based on the measured value, feedback control is performed on a position controller (not shown) of the casting band 34, More preferably, the position of the casting band 34 is adjusted. Further, it is preferable to adjust the casting band 34 immediately below the casting die 31 so that the vertical position fluctuation accompanying the rotation of the rotary roller 33 is 200 μm or less. The temperature of the casting chamber 64 is preferably set to −10 ° C. to 57 ° C. by the temperature control equipment 65. The solvent evaporated inside the casting chamber 64 is recovered by the recovery device 67 and then regenerated and reused as a dope preparation solvent.

  A casting bead is formed from the casting die 31 to the casting band 34, and a casting film 69 is formed on the casting band 34. The temperature of the dope 22 during casting is preferably −10 ° C. to 57 ° C. Further, in order to stabilize the casting bead, the back surface of the casting bead is preferably controlled to a desired pressure value by the decompression chamber 68. The back surface of the bead is preferably decompressed in the range of −2000 Pa to −10 Pa than the front surface. Further, it is preferable that a jacket (not shown) is attached to the decompression chamber 68 and the temperature is controlled so that the internal temperature is kept at a predetermined temperature. The temperature of the decompression chamber 68 is not particularly limited, but is preferably set to be equal to or higher than the condensation point of the organic solvent used. In order to keep the shape of the casting bead desired, it is preferable to attach a suction device (not shown) to the edge portion of the casting die 31. The edge suction air volume is preferably in the range of 1 L / min to 100 L / min.

The dope 22 from the casting die 31 forms a casting bead and is cast on the casting band 34. The viscosity (measured with a rheometer) of the dope 22 during casting is preferably 10 Pa · s or more and 100 Pa · s or less, more preferably 12 Pa · s or more and 50 Pa · s or less, and most preferably 15 Pa · s or more. 40 Pa · s or less.
The casting bead forms a casting film 69 on the casting band 34. A position where the casting bead contacts the casting band 34 is referred to as a casting start position 34a. The viscosity of the dope 22 is preferably 10 Pa · s or more in that the viscosity is not too low, unevenness due to dry air is less likely to be obtained, the surface shape of the cast film 69 is good, and the initial film 69a is easily formed. . Furthermore, the amount of the solvent is not too large, the solvent does not volatilize in the initial stage of drying of the cast film 69, poor drying (for example, foaming, etc.) hardly occurs, and it is not necessary to increase the size of the solvent recovery facility. Is preferable.

  The casting film 69 moves as the casting band 34 moves. A natural wind (hereinafter referred to as an "establishment wind") is generated above the casting film 69. In addition, the area | region until dry air is sent after casting is called the successful wind area | region A. FIG. A labyrinth seal 50 is provided in the growing air region A to prevent the downstream blowing air 56 from flowing back to the vicinity of the casting die 31. In the present invention, the airflow 56 has a wind speed of less than 3 m / s. Normally, the airflow 56 is a weak wind having a wind speed of 2 m / s or less. However, when the airflow 56, which is a turbulent flow, hits the surface of the casting film 69, the surface condition is deteriorated. Therefore, the length L1 (mm) of the successful wind region A is preferably as short as possible. However, the length L1 (mm) should just be 3000 mm or less on the relationship of the arrangement position of each apparatus of the film manufacturing line 20, More preferably, it is 2000 mm or less, More preferably, it is 1000 mm or less. Further, the time required for the casting film 69 to pass through the growing air region A is preferably 15 seconds or less, more preferably 10 seconds or less, and most preferably 7 seconds or less.

  Next, the cast film 69 is continuously transported to a place where the quick drying air blowing port 73 is disposed at the upper part. Drying air 57 is blown toward the casting film 69 from the nozzle 73 a of the quick drying air blowing port 73. The casting film 69 is exposed to the drying air 57, whereby an initial film 69a is formed on the surface thereof. Due to the leveling effect of the initial film 69a, the surface of the casting film 69 is smoothed and dried. In the present invention, the formation of the initial film 69a is not limited to the method of applying the drying air 57. For example, the initial film 69a may be formed by infrared heater heating, microwave heating, or the like.

  The wind speed of the drying air 57 is preferably 3 m / s or more and 15 m / s or less, more preferably 4 m / s or more and 12 m / s or less, and most preferably 4 m / s or more and 10 m / s or less. The wind speed is preferably 3 m / s or more in that the formation of the initial film 69a is smooth and the deterioration of the surface condition of the casting film 69 before the initial film formation can be avoided. Further, the wind speed is preferably 15 m / s or less in that the dry film 57 does not hit the cast film 69 too much and the initial film 69a having excellent surface shape is formed.

  The gas concentration of the drying air 57 is preferably 25% or less, more preferably 20% or less, and most preferably 18% or less. In the present invention, the gas concentration means a volatile solvent component in the dry air 57 measured by infrared analysis. The cast film 69 immediately after formation contains a large amount of solvent. Therefore, the gas concentration of the drying air 57 is preferably 25% or less from the viewpoint that the solvent volatilization from the casting film 69 having a large amount of solvent does not slow down and the initial film 69a can be easily formed.

  The temperature of the drying air 57 is preferably 40 ° C. or higher and 150 ° C. or lower, more preferably 45 ° C. or higher and 120 ° C. or lower, and most preferably 50 ° C. or higher and 100 ° C. or lower. The temperature is preferably 40 ° C. or higher in that the initial film 69a having a good film surface can be formed because the volatilization of the solvent from the cast film 69 easily proceeds. Further, the temperature is preferably 150 ° C. or lower in that there is no foaming of the solvent in the casting film 69, rapid volatilization does not occur, and it is easy to form the initial film 69a having a good surface shape.

  In the present invention, it is preferable that the time that the growing wind 56 hits the casting film 69 be 15 seconds or less after casting, more preferably 10 seconds or less, and most preferably 7 seconds or less. It is a rapid drying, and before the uniform initial film 69 a is formed on the surface of the casting film 69, it is possible to avoid the formation of uneven thickness on the surface of the casting film 69 and to obtain a film 82 having a uniform surface. In this respect, it is preferable that the time required for the blowing air 56 to hit the casting film 69 is 15 seconds or less. Moreover, since the drying time is short, the productivity of the film 82 is good.

  The content of the solvent at the time of starting the drying of the cast film 69 is preferably 200% by mass or more and 500% by mass or less, more preferably 250% by mass or more and 450% by mass or less based on the solid content. Preferably they are 300 mass% or more and 420 mass% or less.

  It is preferable that the decrease rate of the residual solvent of the casting film 69 for 30 seconds after the drying air 57 is sent to the casting film 69 is 1 mass% / s or more and 12 mass% / s or less, and 3 mass%. More preferably, it is more than / s and 11 mass% / s or less, Most preferably, they are 5 mass% / s or more and 10 mass% / s or less. The drying rate is preferably 1% by mass / s or more in that the delay in the formation of the initial film 69a can be suppressed and the initial film 69a having sufficient film surface strength can be easily formed. In addition, the drying rate is preferably 12% by mass / s or less from the viewpoint that the initial film 69a is formed uniformly and foaming of the cast film 69 and deterioration of the surface condition of the film surface can be suppressed.

  The casting film 69 moves as the casting band 34 travels. At this time, drying air is applied to the casting film 69 through the air blowing ports 70, 71, 72 to promote evaporation of the solvent. The surface of the casting film 69 may fluctuate due to the blowing of the dry air, but the labyrinth seal 50 suppresses this fluctuation. The surface temperature of the casting band 34 is preferably −20 ° C. to 40 ° C.

  After the casting film 69 has self-supporting properties, the casting film 69 is peeled off from the casting band 34 while being supported by the peeling roller 75 as a wet film 74. The amount of residual solvent at the time of stripping is preferably 20% by mass to 250% by mass based on the solid content. Thereafter, the transfer section 80 provided with a large number of rollers is conveyed, and the wet film 74 is fed into the tenter dryer 35. In the transfer part 80, the drying of the wet film 74 is advanced by sending the drying air of desired temperature from the air blower 81. FIG. At this time, the temperature of the drying air is preferably 20 ° C to 250 ° C. In the transition section 80, it is also possible to apply a draw tension to the wet film 74 by making the rotation speed of the downstream roller faster than the rotation speed of the upstream roller.

  The wet film 74 sent to the tenter dryer 35 is dried while being conveyed by being gripped by clips at both ends thereof. Moreover, it is preferable to divide the inside of the tenter dryer 35 into temperature zones and adjust the drying conditions appropriately for each of the zones. It is also possible to stretch the wet film 74 in the width direction using the tenter dryer 35. As described above, it is preferable that at least one direction of the wet film 74 in the casting direction and the width direction is stretched by 1.01 to 2.0 times by the crossing portion 80 and / or the tenter dryer 35. More preferably, the film is stretched 1.01 to 1.5 times, and more preferably 1.01 to 1.3 times.

  The wet film 74 is dried to a predetermined residual solvent amount by the tenter dryer 35 and then sent to the downstream side as a film 82. Both ends of the film 82 are cut at both edges by the edge-cutting device 40. The cut side end portion is sent to the crusher 90 by a cutter blower (not shown). The crusher 90 pulverizes the film side end portion into a chip. Since this chip is reused for dope preparation, this method is effective in terms of cost. In addition, although it can also abbreviate | omit about the cutting process of this film both ends, it is preferable to carry out in any one from the said casting process to the process of winding up the said film.

  The film 82 from which both side ends have been removed is sent to the drying chamber 41 and further dried. Although the temperature in the drying chamber 41 is not specifically limited, It is preferable that it is the range of 50 to 160 degreeC. In the drying chamber 41, the film 82 is conveyed while being wound around a roller 91, and the solvent gas generated by evaporation here is adsorbed and recovered by an adsorption recovery device 92. The air from which the solvent component has been removed is blown again as dry air inside the drying chamber 41. The drying chamber 41 is more preferably divided into a plurality of sections in order to change the drying temperature. In addition, if a preliminary drying chamber (not shown) is provided between the ear opener 40 and the drying chamber 41 and the film 82 is preliminarily dried, the film temperature is prevented from rising rapidly in the drying chamber 41. The shape change of the film 82 can be further suppressed.

  The film 82 is cooled to approximately room temperature in the cooling chamber 42. A humidity control chamber (not shown) may be provided between the drying chamber 41 and the cooling chamber 42, and air adjusted to a desired humidity and temperature can be blown onto the film 82 in the humidity control chamber. It is preferable. Thereby, generation | occurrence | production of the curling of the film 82 and the winding defect at the time of winding can be suppressed.

  Further, the forcible charge removal device (charge removal bar) 93 sets the charged voltage while the film 82 is being conveyed to a predetermined range (for example, −3 kV to +3 kV). Although FIG. 1 illustrates an example provided on the downstream side of the cooling chamber 42, the position is not limited thereto. Furthermore, it is preferable to provide a knurling roller 94 to give knurling to both edges of the film 82 by embossing. In addition, it is preferable that the unevenness | corrugation of the knurled location is 1 micrometer-200 micrometers.

  Finally, the film 82 is taken up by the take-up roller 95 in the take-up chamber 43. At this time, it is preferable to wind the sheet while applying a desired tension with the press roller 96. More preferably, the tension is gradually changed from the start to the end of winding. The film 82 to be wound is preferably at least 100 m in the longitudinal direction (casting direction). Moreover, it is preferable that the width | variety of the film 82 is 600 mm or more, and it is more preferable that they are 1400 mm or more and 1800 mm or less. The present invention is also effective when it is larger than 1800 mm. The present invention is also applied when a thin film having a thickness of 15 μm or more and 100 μm or less is manufactured.

In the solution casting method of the present invention, at the time of casting the dope, two or more kinds of dopes can be simultaneously laminated or sequentially laminated. Furthermore, you may combine both casting. When performing simultaneous lamination and co-casting, a casting die to which a feed block is attached may be used, or a multi-manifold casting die may be used. It is preferable that at least one of the thickness of the layer on the air surface side and the thickness of the layer on the support side is 0.5% to 30% of the thickness of the entire film in the film composed of multiple layers by co-casting.
When performing simultaneous lamination co-casting, it is preferable that the high-viscosity dope is wrapped with the low-viscosity dope when the dope is cast from the die slit to the support. Moreover, the solid concentration of the dope of the outer layer is preferably a low concentration of 1 mass% or more than the solid concentration of the inner layer of the dope, more preferably a low concentration of 3 mass% or more. In addition, it is preferable that the dope contacting the outside world has a larger alcohol composition ratio than the internal dope. The amount of the dope alcohol added to the outer layer is preferably 1.05 to 6.0 times, more preferably 1.2 to 4.0 times, and more preferably 1.5 to 3.0 times that of the inner layer. It is particularly preferred that

  From casting die, decompression chamber, support structure, co-casting, peeling method, stretching, drying conditions for each process, handling method, curl, winding method after flatness correction, solvent recovery method, film recovery method The details are described in paragraphs [0617] to [0889] of Japanese Patent Application No. 2004-264464. These descriptions are also applicable to the present invention.

  Furthermore, this invention relates to the polarizing plate characterized by using the said cellulose acylate film as a protective film of a polarizer.

<Polarizing plate>
A polarizing plate consists of a polarizer and two transparent protective films arrange | positioned at the both sides. The cellulose ester film of the present invention can be used as at least one protective film. 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 using the cellulose-ester film of this invention as a polarizing plate protective film, the preparation methods of a polarizing plate are not specifically limited, It can produce 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 cellulose ester film of the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer and the slow axis of the cellulose ester film of the present invention are matched. In addition, when the polarizing plate produced under polarizing plate cross Nicol was evaluated, the orthogonality accuracy between the slow axis of the cellulose ester film of the present invention and the absorption axis of the polarizer (axis orthogonal to the transmission axis) was 1 °. When larger, it was found that the polarization degree performance under the polarizing plate crossed Nicols was lowered and light leakage occurred. In this case, when combined with a liquid crystal cell, sufficient black level and contrast cannot be obtained. Therefore, the deviation between the direction of the main refractive index nx of the cellulose ester film of the present invention and the direction of the transmission axis of the polarizing plate is preferably within 1 °, preferably within 0.5 °.

<Surface treatment>
The cellulose ester 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-mentioned conditions, and examples thereof include 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 JIII Journal of Technical Disclosure No. 2001-1745 (issued on 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, and more preferably 12 or more. The reaction conditions during 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 the transparent protective film, or a medium refractive index layer, a high refractive index layer, and a low refractive index layer are formed on the 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. It is preferable that the matting particles are dispersed in the light scattering layer, and the refractive index of the material other than the matting particles in the light scattering layer is preferably in the range of 1.50 to 2.00. The refractive index is preferably in the range of 1.35 to 1.49. The light scattering layer may have both antiglare properties and hard coat properties, and may be a single layer or may be composed of 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 an 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.
In addition, the ratio of the minimum value and the maximum value of the reflectance within the range of a ^* value −2 to 2, b ^* value −3 to 3, and 380 nm to 780 nm in the light source under 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 according to the present invention is preferably 1.20 to 1.49, more preferably 1.30 to 1.44. Furthermore, the low refractive index layer preferably satisfies the following formula (XI) from the viewpoint of reducing the reflectance.

Formula (XI): (m / 4) × 0.7 <n ¹ d ¹ <(m / 4) × 1.3

In the formula, m is a positive odd number, n ¹ is the refractive index of the low refractive index layer, and d ¹ is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength and is a value in the range of 500 to 550 nm.

The material for forming the low refractive index layer according to the present invention will be described below.
The low refractive index layer according to the present invention preferably contains a fluorine-containing polymer as a low refractive index binder. The fluorine polymer is preferably a fluorine-containing polymer that is crosslinked by heat or ionizing radiation with a coefficient of dynamic friction of 0.03 to 0.20, a contact angle with water of 90 to 120 °, and a sliding angle of pure water of 70 ° or less. When the antireflection film according to 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. 1N or less is most preferable. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch, preferably 0.3 GPa or more, more preferably 0.5 GPa or more.

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

  Specific examples of the 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 fluorine-containing monomer unit and the structural unit for imparting crosslinking reactivity, a monomer that does not contain a fluorine atom may be copolymerized as appropriate from the viewpoint of solubility in a solvent and film transparency. The monomer unit that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2) -Ethylhexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyltoluene, α-methylstyrene, etc.), vinyl ethers (methyl) Vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate etc.), acrylamides (N-tert-butylacrylamide, N- 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 generally 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 usually contains a binder for imparting hard coat properties, matte particles for imparting light diffusibility, and inorganic fillers for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength as necessary. Is done.

  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 these monomers having an ethylenically unsaturated group can be carried out 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 has matte particles, such as inorganic compound particles or resin particles, which are larger than filler particles and have an average particle size of usually 1 to 10 μm, preferably 1.5 to 7.0 μm. It is preferable to contain.
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.

  Furthermore, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less, more preferably 0.1% of the total number of particles. 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 preferably 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less is contained.
Conversely, in order to increase the difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the light scattering layer using the high refractive index mat particles low. The preferred particle size is the same as that of the 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 from the viewpoint of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the light scattering layer, more preferably 20 to 80%, and particularly preferably 30 to 75%.
Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of binder and inorganic filler in the light scattering layer is preferably 1.48 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. It is preferable to contain in a composition. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the antireflection film of the present invention appears in a smaller addition amount. The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity.

Next, an antireflection layer in which a middle refractive index layer, a high refractive index layer, and a low refractive index layer are laminated in this order on the transparent protective film will be described.
An antireflection film comprising at least a middle refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) in order on the substrate must be designed to have a refractive index satisfying the following relationship: Is preferred.

  Refractive index of high refractive index layer> refractive index of medium refractive index layer> refractive index of transparent support> refractive index of low refractive index layer

A hard coat layer may be provided between the transparent support and the medium refractive index layer. 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. Examples of such a layer 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 preferably 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.
The inorganic compound fine particles having a high refractive index are preferably inorganic compounds having a refractive index of 1.65 or more, 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 treatment agent (for example, silane coupling agents, etc .: JP-A-11-295503, JP-A-11-153703, JP-A-2000-9908). , Anionic compounds or organometallic coupling agents: Japanese Patent Application Laid-Open No. 2001-310432), 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>
In the above configuration, the low refractive index layer is sequentially laminated on the high refractive index layer. The refractive index of the low refractive index layer is preferably 1.20 to 1.55. More preferably, it is 1.30-1.50.
It is preferable to construct as an outermost layer having scratch resistance and antifouling properties. 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], JP-A 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>
In general, 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 composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO 00/46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.
The hard coat layer can also serve as an antiglare layer (described later) provided with, for example, particles having an average particle size of 0.2 to 10 μm and imparted with an antiglare function (antiglare function).
The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.
The strength of the hard coat layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400. Moreover, in the Taber test according to JIS K5400, the smaller the amount of wear 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 case where the dependence is large and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material. It is preferable to use an uncolored metal oxide as the conductive layer material because the coloration of the entire film is suppressed. Zn, Ti, Al, In, Si, Mg, Ba, Mo, W, or V can be given as the metal that forms a metal oxide without coloring, and a metal oxide containing this as a main component is 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. In particular, ZnO, TiO ₂ and SnO ₂ are preferable. Examples of containing different atoms include, for example, additives such as Al and In for ZnO, addition of Sb, Nb and halogen elements for SnO ₂ , and Nb and TA for TiO ₂ . Addition is effective. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a material obtained by adhering the above metal oxide to other crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. The volume resistance value and the surface resistance value are different physical properties and cannot be simply compared. However, in order to ensure conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance, the conductivity 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 ester film of the present invention and the polarizing plate using the film can be used for liquid crystal cells and liquid crystal display devices in 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 and 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 (in Japanese Patent Publication No. 176625), and (2) a liquid crystal cell (SID97, Digest of tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (for MVA mode) in order to enlarge the viewing angle. ), (3) A 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 Japan 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 transmission type liquid crystal display device of the present invention, the polymer film 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 a row.
In another aspect of the transmissive liquid crystal display device of the present invention, an optical compensation sheet made of the polymer 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 polymer film may be used only for the transparent protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, or two (between the liquid crystal cell and the polarizer) of both polarizing plates. You may use said polymer film for a transparent protective film of a sheet. When the polymer film 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. For the lamination to the liquid crystal cell, the polymer film of the present invention is preferably on the VA cell side. The protective film may be a normal cellulose ester film, and is preferably thinner than the polymer film of the present invention. For example, 40-80 μm is preferable, and examples include, but are not limited to, commercially available KC4UX2M (40 μm manufactured by Konica Capto Corporation), KC5UX (60 μm manufactured by Konica Caputo 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.

[Example 1: Film formation of cellulose acylate films F1 to F23]
(1) Cellulose acylate Cellulose acylates having different degrees of acyl substitution described in Table 1 were prepared. In this, sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) was added as a catalyst, carboxylic acid was added, and an acylation reaction was performed at 40 ° C. Thereafter, the total substitution degree and the 6-position substitution degree were adjusted by adjusting the amount of sulfuric acid catalyst, the amount of water, and the aging time. The aging temperature was 40 ° C. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone. In the table, CAB is an abbreviation for cellulose acetate butyrate (cellulose ester derivative in which an acyl group is an acetate and a butyryl group), and CAP is cellulose acetate propionate (an acyl group is an acetate group and a propionyl group). CTA means cellulose triacetate (cellulose ester derivative in which an acyl group is composed only of an acetate group). Moreover, in the following description, these are generically called a cotton raw material.

(2) Composition (2-1) Cellulose acylate solution The following composition was put into a mixing tank, and each component was dissolved by stirring. It filtered with the sintered metal filter of the hole diameter of 10 micrometers.

―――――――――――――――――――――――――――――――――
Cellulose acylate solution ――――――――――――――――――――――――――――――――――
Cellulose acylate described in Table 1 100.0 parts by mass Triphenyl phosphate 7.9 parts by mass Biphenyl diphenyl phosphate 3.9 parts by mass Methylene chloride 403.0 parts by mass Methanol 60.2 parts by mass ――――――――――――――――――――――――――

(2-2) Matting Agent Dispersion Solution Next, the following composition containing the cellulose acylate solution prepared by the above method was charged into a dispersing machine to prepare a matting agent dispersion.

――――――――――――――――――――――――――――――――――
Matting agent dispersion ――――――――――――――――――――――――――――――――――
Silica particles having an average particle diameter of 16 nm (aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride 72.4 parts by mass Methanol 10.8 parts by mass Cellulose acylate solution 10.3 parts by mass ――――――――――――――――――――――――――――

  100 parts by mass of the cellulose acylate solution and 1.35 parts by mass of the matting agent dispersion were mixed to prepare a dope for film formation. This dope was used for film production of F14 to F17, F20 and F21.

(2-3) 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 used for film formation of F1-F10, F13, F18, F19, F22 and F23.

(2-4) 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 so as to have the ratio shown in Table 2 to prepare a dope for film formation. This dope was used for film formation of F11 and F12.
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.

[Example 2: Film formation of polymer films F27 to F43]
(1) Polymer The cotton described in Table 1 and the cyclic polyolefin described below are collectively referred to as a polymer material.

<Preparation of cyclic polyolefin polymer (P-1)>
100 parts by mass of purified toluene and 100 parts by mass of norbornenecarboxylic acid methyl ester were charged into the reaction kettle. Next, ethylhexanoate-Ni 25 mmol% (based on monomer) dissolved in toluene, tri (pentafluorophenyl) boron 0.225 mol% (based on monomer) and triethylanilinium 0.25 mol% (based on monomer) dissolved in toluene Mass) was charged into the reaction kettle. The reaction was allowed to proceed for 18 hours at room temperature with stirring. After completion of the reaction, the reaction mixture was put into excess ethanol to produce a polymer precipitate. The polymer (P-1) obtained by purifying the precipitate was vacuum dried at 65 ° C. for 24 hours.

(2) Composition (2-1) Preparation of polymer solutions (D1) and (D2) The following composition was placed in a mixing tank, stirred to dissolve each component, and further heated to 90 ° C. for about 10 minutes. It filtered with the filter paper with an average hole diameter of 34 micrometers, and the sintered metal filter with an average hole diameter of 10 micrometers.

(2-1-1) Polymer solution (D1) for film formation of polymer films F28, F30, F32, F34, F36, F38, F40

───────────────────────────────────────── Polymer solution (D1)
――――――――――――――――――――――――――――――――――――――――
Cellulose acylates listed in Tables 1 to 3 100.0 parts by mass Triphenyl phosphate 7.9 parts by mass Biphenyl diphenyl phosphate 3.9 parts by mass Methylene chloride 403.0 parts by mass An alcohol having 6 or less carbon atoms * 60.2 parts by mass ―――――――――――――――――――――――――――――――――――――――― * “6 carbon atoms used for each film The following “alcohols” are listed in Table 3.

(2-1-2) Polymer solution (D2) for forming polymer films F27, F29, F31, F33, F35, F37, F39, and F41

────────────────────────────────────────
Polymer solution (D2)
────────────────────────────────────────
Cellulose acylates listed in Tables 1 to 3 100.0 parts by mass Triphenyl phosphate 7.9 parts by mass Biphenyl diphenyl phosphate 3.9 parts by mass Methylene chloride 347.4 parts by mass Alcohol having 6 or less carbon atoms * 115.8 parts by mass ───────────────────────────────────────── * 6 carbon atoms used for each film The following “alcohols” are listed in Table 3.

(2-2) Preparation of polymer solution (D3) The following composition was put into a mixing tank, stirred to dissolve each component, and then filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm.

(2-2-1) Polymer solution (D3) for producing polymer film F42
――――――――――――――――――――――――――――――――――――――――
Polymer solution (D3)
────────────────────────────────────────
Cyclic polyolefin (P-1) 150.0 parts by mass Dichloromethane 391.5 parts by mass Methanol 58.5 parts by mass ────────────────────────── ──────────────

(2-2-2) Polymer solution (D4) for production of polymer film F43
────────────────────────────────────────
Polymer solution (D4)
────────────────────────────────────────
Cyclic polyolefin (P-1) 150.0 parts by mass Dichloromethane 337.5 parts by mass Methanol 112.5 parts by mass ────────────────────────── ──────────────

(2-3) Matting agent dispersion Next, the following composition containing the polymer solution prepared by the above method was thrown into a dispersing machine to prepare a matting agent dispersion.

(2-3-1) Matting agent dispersion (M1) for preparing polymer films F28, F30, F32, F34, F36, F38, F40
────────────────────────────────────────
Matting agent dispersion (M1)
────────────────────────────────────────
Silica particles with an average particle size of 16 nm
(Aerosil R972 Nippon Aerosil Co., Ltd.) 2.0 parts by mass methylene chloride 72.4 parts by mass (2-1-1) alcohol having 6 or less carbon atoms * 10.8 parts by mass polymer solution (D1) 10 .3 parts by mass ──────────────────────────────────────── * Used for each film “Alcohol having 6 or less carbon atoms” is shown in Table 3.

(2-3-2) Matting agent dispersion liquid (M2) for forming polymer films F27, F29, F31, F33, F35, F37, F39, and F41
────────────────────────────────────────
Matting agent dispersion (M2)
────────────────────────────────────────
Silica particles having an average particle diameter of 16 nm (aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride 62.8 parts by mass (2-1-2) Alcohol having 6 or less carbon atoms * 20.8 parts by mass Part polymer solution (D2) 10.3 parts by mass -------------------------- — * “Alcohols having 6 or less carbon atoms” used in each film are listed in Table 3.

(2-3-3) Matting agent dispersion for forming polymer film F42 (M3)
────────────────────────────────────────
Matting agent dispersion (M3)
――――――――――――――――――――――――――――――――――――――――
Silica particles having an average particle diameter of 16 nm (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride 72.4 parts by mass (2-2-1) Alcohol having 6 or less carbon atoms * 10.8 masses Part polymer solution (D3) 10.3 parts by mass ─────────────────────────────────────── — * “Alcohols having 6 or less carbon atoms” used in each film are listed in Table 3.

  100 parts by mass of the polymer solution (D3) and 1.35 parts of the matting agent dispersion (M3) were mixed to prepare a dope for forming a film, which was used for F42 film creation.

(2-3-4) Matting agent dispersion for forming polymer film F43 (M4)
────────────────────────────────────────
Matting agent dispersion (M4)
────────────────────────────────────────
Silica particles having an average particle diameter of 16 nm (aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.0 parts by mass Methylene chloride 62.4 parts by mass (2-2-2) C6 or less alcohol used * 20.8 parts by mass Part polymer solution (D2) 10.3 parts by mass -------------------------- — * “Alcohols having 6 or less carbon atoms” used in each film are listed in Table 3.

100 parts by mass of the polymer solution (D4) and 1.35 parts by weight of the matting agent dispersion (M4) were mixed to prepare a dope for film formation, and used for film formation for F43.

(2-4) Retardation developer solution C
Next, the following composition containing the polymer solution prepared by the above method was put into a mixing tank and dissolved by stirring while heating to prepare a retardation developer solution C.

(2-4-1) Retardation developer solution (C1) for preparing polymer films F28, F30, F32, F34, F36, F38, F40
────────────────────────────────────────
Retardation developer A 20.0 parts by mass Methylene chloride 58.3 parts by mass (2-1-1) Alcohol having 6 or less carbon atoms * 8.7 parts by mass Polymer solution (D1) 12.8 parts by mass ─────────────────────────────────────── * * 6 carbon atoms or less used for each film The “alcohols” are listed in Table 3.

  100 parts by mass of the polymer solution (D1), 1.35 parts by mass of the matting agent dispersion (M1), and the retardation developer solution (C1) are mixed so as to have the ratio shown in Table 3, and the dope for film formation is mixed. Prepared. This dope was used for film formation of F28, F30, F32, F34, F36, F38 and F40.

(2-4-2) Retardation agent solution for producing polymer films F27, F29, F31, F33, F35, F37, F39, and F41 (C2)
────────────────────────────────────────
Retardation developer A 20.0 parts by mass Methylene chloride 50.25 parts by mass (2-1-2) Alcohol having 6 or less carbon atoms * 16.75 parts by mass Polymer solution (D2) 12.8 parts by mass ─────────────────────────────────────── * * 6 carbon atoms or less used for each film The “alcohols” are listed in Table 3.

  100 parts by mass of the polymer solution (D2), 1.35 parts by mass of the matting agent dispersion (M2), and the retardation developer solution (C2) are mixed so as to have the ratio shown in Table 3, and the dope for film formation is mixed. Prepared. This dope was subjected to film formation of F27, F29, F31, F33, F35, F37, F39 and F41.

  Although the solution casting method will be described in detail later, the same conditions as those for the polymer film F4 were used for the drying and stretching conditions during solution casting film formation.

(3) Casting (3-1) Dope Preparation The above-mentioned plurality of solvents were mixed and stirred well in a 4000 L stainless steel dissolution tank having stirring blades to obtain a mixed solvent. In addition, as each raw material of a solvent, that whose water content is 0.5 mass% or less was used. Next, flaky powder of cotton raw material was gradually added from the hopper. The cotton raw material powder is put into a dissolution tank and is initially stirred under a condition that a dissolver type eccentric agitator that stirs at a peripheral speed of 5 m / sec and a stirrer having an anchor blade on the central shaft at a peripheral speed of 1 m / sec. Dispersed for 30 minutes. The temperature at the start of dispersion was 25 ° C., and the final temperature reached 48 ° C. Furthermore, the additive solution prepared in advance (the matting agent dispersion, or in some cases, the mixed solution of the matting agent dispersion and the retardation developing agent) is adjusted so that the total amount of the additive tank is 2000 kg. Liquid was sent. After finishing the dispersion of the additive solution, the high speed stirring was stopped. Then, the peripheral speed of the anchor blade was set to 0.5 m / sec, and the mixture was further stirred for 100 minutes to swell the cotton raw material powder to obtain a swelling liquid. Until the end of swelling, the inside of the dissolution tank was pressurized to 0.12 MPa with nitrogen gas. The inside of the dissolution tank at this time was kept in a state where there was no problem in terms of explosion prevention because the oxygen concentration was less than 2 vol%. The amount of water in the swelling liquid was 0.3% by mass.

(3-2) Dissolution / filtration The swelling liquid was sent to a pipe with a dissolution tank jacket. The swelling liquid was heated to 50 ° C. with a jacketed pipe, and further heated to 90 ° C. under a pressure of 2 MPa to completely dissolve. The heating time at this time was 15 minutes. Next, the temperature of the dissolved liquid was lowered to 36 ° C. with a temperature controller, and the solution was passed through a filtration device having a filter medium having a nominal pore diameter of 8 μm to obtain a dope (hereinafter referred to as a dope before concentration). At this time, the primary pressure in the filtration device was 1.5 MPa, and the secondary pressure was 1.2 MPa. The filters, housings, and piping exposed to high temperatures were made of Hastelloy (trade name) alloy and had excellent corrosion resistance, and were equipped with a jacket for circulating a heat transfer medium for heat insulation and heating.

(3-3) Concentration / Filtration / Defoaming / Additive The dope before concentration thus obtained is flash-evaporated in a flash apparatus at normal pressure at 80 ° C., and the evaporated solvent is recovered by a condenser. did. The solid content concentration of the dope 22 after the flash was 21.8% by mass. The condensed solvent was recovered with a recovery device to be reused as a dope preparation solvent. After regenerating with a regenerator, the solution was sent to a solvent tank. Distillation and dehydration were performed in the recovery device and the regeneration device. The flash tank of the flash device was provided with a stirrer (not shown) having an anchor blade on the stirring shaft, and the dope 22 flashed by the stirrer at a peripheral speed of 0.5 m / sec was stirred for defoaming. The temperature of the dope 22 in this flash tank was 25 ° C., and the average residence time of the dope 22 in the tank was 50 minutes. The dope 22 was collected and the shear viscosity measured at 25 ° C. was 450 Pa · s at a shear rate of 10 (sec −1).

  Next, bubbles were removed by irradiating the dope 22 with weak ultrasonic waves. After that, it was passed through a filtration device while being pressurized to 1.5 MPa using a pump. In the filtration apparatus, first, a sintered fiber metal filter having a nominal pore diameter of 10 μm was passed, and then a sintered fiber filter having a same pore size of 10 μm was passed. Respective primary pressures were 1.5 MPa and 1.2 MPa, and secondary pressures were 1.0 MPa and 0.8 MPa. The dope temperature after filtration was adjusted to 36 ° C., and the dope 22 was fed into a 2000 L stainless steel stock tank 21 and stored. The stock tank 21 has a stirrer 61 having an anchor blade on the central axis, and was constantly stirred at a peripheral speed of 0.3 m / sec. In addition, when the dope was prepared from the dope before concentration, no problem such as corrosion occurred at all in the wetted part of the dope.

Moreover, the mixed solvent A with 87.0 mass parts of methylene chloride and 13.0 mass parts of methanol was produced.

(3-4) Discharge / immediate addition / casting / bead depressurization A film 82 was produced using the film production line 20 shown in FIG. The dope 22 in the stock tank 21 was sent to the filtration device 30 by a high-precision gear pump 62. This gear pump 62 has a function of increasing the pressure on the primary side of the pump 62 and feeds the liquid by performing feedback control on the upstream side of the gear pump 62 with an inverter motor so that the pressure on the primary side becomes 0.8 MPa. . A gear pump 62 having a volume efficiency of 99.2% and a discharge rate variation rate of 0.5% or less was used. The discharge pressure was 1.5 MPa. Then, the dope 22 that passed through the filtration device 30 was fed to the casting die 31.

  The casting die 31 was cast by adjusting the flow rate of the dope 22 at the outlet of the casting die 31 so that the width of the casting die 31 was 1.8 m and the thickness of the dried film 82 was 80 μm. At this time, the viscosity of the dope 22 was 20 Pa · s. The casting width of the dope 22 from the discharge port of the casting die 31 was 1700 mm. The casting speed was 20 m / min. In order to adjust the temperature of the dope 22 to 36 ° C., a jacket (not shown) was provided on the casting die 31 and the inlet temperature of the heat transfer medium supplied into the jacket was set to 36 ° C.

  The casting die 31 and the piping were all kept at 36 ° C. during film formation. The casting die 31 was a coat hanger type die. The casting die 31 was provided with thickness adjusting bolts at a pitch of 20 mm and equipped with an automatic thickness adjusting mechanism using a heat bolt. The heat bolt can also set a profile according to the liquid feed amount of the gear pump 62 by a preset program, and is fed back by an adjustment program based on the profile of an infrared thickness meter (not shown) installed in the film production line 20. The thing which has the performance which can also be controlled was used. In the film excluding the edge 20 mm, the thickness difference between two arbitrary points 50 mm apart was within 1 μm, and the thickness variation in the width direction was adjusted to 3 μm / m or less. The overall thickness was adjusted to ± 1.5% or less.

  In addition, a decompression chamber 68 for decompressing this portion was installed on the primary side of the casting die 31. The degree of decompression of the decompression chamber 68 is adjusted so that a pressure difference of 1 Pa to 5000 Pa is generated before and after the casting bead, and this adjustment is made according to the casting speed. At that time, the pressure difference on both sides of the casting bead was set so that the length of the casting bead was 20 mm to 50 mm. The decompression chamber 68 was provided with a mechanism that can be set to a temperature higher than the condensation temperature of the gas around the casting portion. A labyrinth seal 50 (see FIG. 2) was provided on the front surface of the bead at the die discharge port. Also, openings were provided at both ends of the die discharge port of the casting die. Further, an edge suction device (not shown) for adjusting the disturbance of both edges of the casting bead was attached to the casting die 31.

(3-5) Casting Die As the material of the casting die 31, precipitation hardening type stainless steel having a coefficient of thermal expansion of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less was used. This had a corrosion resistance substantially equal to that of SUS316 in a forced corrosion test with an aqueous electrolyte solution. Further, even when immersed in a mixed solution of dichloromethane, methanol and water for 3 months, it had corrosion resistance that did not cause pitting (opening) at the gas-liquid interface. The finishing accuracy of the wetted surface of the casting die 31 was 1 μm or less in terms of surface roughness, the straightness was 1 μm / m or less in any direction, and the slit clearance was adjusted to 1.5 mm. About the corner | angular part of the liquid-contacting part of the lip | tip end of the casting die 31, what was processed so that R might be set to 50 micrometers or less over the full width of a slit was used. The shear rate of the dope 22 inside the casting die 31 was in the range of 1 (1 / sec) to 5000 (1 / sec). Further, a WC (tungsten carbide) coating was performed on the lip end of the casting die 31 by a thermal spraying method to provide a cured film.

  Further, in order to prevent the outflowing dope 22 from being locally dried and solidified, the mixed solvent A for solubilizing the dope 22 is discharged from both sides of the casting bead to the discharge port of the casting die 31. Each 0.5 ml / min was supplied to the interface with the outlet. The pulsation rate of the pump supplying the mixed solvent was 5% or less. Further, the pressure on the back side of the casting bead was lowered by 150 Pa from the front side by the decompression chamber 68. A jacket (not shown) was attached to make the internal temperature of the decompression chamber 68 constant at a predetermined temperature. A heat transfer medium adjusted to 35 ° C. was supplied into the jacket. The edge suction device can adjust the edge suction air volume so as to be in the range of 1 L / min to 100 L / min, and in the present embodiment, this is in the range of 30 L / min to 40 L / min. Adjusted appropriately.

(3-6) Metal Support A stainless steel endless band having a width of 2.1 m and a length of 70 m was used as the casting band 34 as a support. The casting band 34 was polished so that the thickness was 1.5 mm and the surface roughness was 0.05 μm or less. The material is made of SUS316 and has sufficient corrosion resistance and strength. The thickness unevenness of the entire casting band 34 was 0.5% or less. The casting band 34 was driven by two rotating rollers 32 and 33. At that time, the tension in the conveying direction of the casting band 34 was adjusted to 1.5 × 10 ⁵ N / m ² . The relative speed difference between the casting band 34 and the rotating rollers 32 and 33 was adjusted to be 0.01 m / min or less. At this time, the speed fluctuation of the casting band 34 was set to 0.5% or less. Further, both end positions of the casting band 34 were detected and controlled so that the meandering in the width direction of one rotation was limited to 1.5 mm or less. The positional fluctuation in the vertical direction between the die lip tip and the casting band 34 immediately below the casting die 31 was set to 200 μm or less. The casting band 34 was installed in a casting chamber 64 having wind pressure fluctuation suppressing means (not shown). The dope 22 was cast on the casting band 34 from the casting die 31.

As the rotating rollers 32 and 33, those capable of feeding a heat transfer medium therein were used so that the temperature of the casting band 34 could be adjusted. A 5 ° C. heat transfer medium was passed through the rotary roller 33 on the casting die 34 side, and a 40 ° C. heat transfer medium was passed through the other rotary roller 32 for drying. The surface temperature of the central part of the casting band 34 immediately before casting was 15 ° C., and the temperature difference between both side ends was 6 ° C. or less. The casting band 34 preferably has no surface defects, has no pinholes of 30 μm or more, has no pinholes of 10 μm to 30 μm, 1 pin / m ² or less, and ² pinholes of less than 10 μm / Those with m ² or less were used.

(3-7) Casting drying The temperature of the casting chamber 64 was kept at 35 ° C. using the temperature control equipment 65. The dope 22 was cast on the casting band 34 to form a casting film 69. In addition, the quick drying air blowing port 73 was attached, and the drying film 57 was applied to the surface of the casting film 69 to form the initial film 69a. At this time, the passage time of the growth air region A, the wind speed of the drying air 57, and the temperature were adjusted to satisfy the conditions shown in Table 2. Moreover, the wind speed of the growth wind was adjusted to 0.2 m / s or less, and the gas concentration of the dry wind 57 was adjusted to 16%. The drying rate of the cast film 69 at the quick drying wind port 73 was 7% by mass / s on the basis of the dry amount.

  A drying air of 135 ° C. was blown from the air blowing port 70 on the upstream side of the casting band 34. Further, 140 ° C. dry air was blown from the air blowing port 71 on the downstream side, and 65 ° C. dry air was blown from the air blowing port 72 below the casting band 34. The saturation temperature of each drying wind was around -8 ° C. The oxygen concentration in the dry atmosphere on the casting band 34 was kept at 5 vol%. In order to maintain this oxygen concentration at 5 vol%, the air was replaced with nitrogen gas. Further, in order to condense and recover the solvent in the casting chamber 64, a condenser (condenser) 66 was provided, and the outlet temperature thereof was set to -10 ° C.

The labyrinth seal 50 suppressed the static pressure fluctuation in the vicinity of the casting die 31 to ± 1 Pa or less. When the solvent ratio in the cast film 69 reached 50% by mass on the dry basis, the cast film was peeled off as a wet film 74 while being supported by the peel roller 75 from the cast band 34. The solvent content based on the dry weight is a value calculated by {(xy) / y} × 100, where x is the film mass at the time of sampling and y is the mass after the sampling film is dried. It is. The stripping tension is 1 × 10 ² N / m ^2, and the stripping speed (stripping roller draw) is 100.1% to 110% with respect to the speed of the casting band 34 in order to suppress stripping failure. Adjusted appropriately in range. The surface temperature of the peeled wet film 74 was 15 ° C. The solvent gas generated by the drying was condensed and liquefied by a condenser 66 at −10 ° C. and recovered by a recovery device 67. The recovered solvent was adjusted so that the water content was 0.5% or less. The drying air from which the solvent was removed was heated again and reused as drying air. The wet film 74 was conveyed through the roller of the crossing section 80 and sent to the tenter dryer 35. In the crossover 80, 40 ° C. dry air was blown from the blower 81 to the wet film 74. In addition, a tension of about 30 N was applied to the wet film 74 while being transported by the roller of the crossing section 80.

(3-8) Tenter Transport / Drying / Ear Cutting The wet film 74 sent to the tenter dryer 35 is transported in the drying zone of the tenter dryer 35 while being fixed at both ends with clips. Dried. The clip was cooled by supplying a heat transfer medium at 20 ° C. The clip was conveyed by a chain, and the speed fluctuation of the sprocket was 0.5% or less. Further, the interior of the tenter dryer 35 was divided into three zones, and the drying air temperature in each zone was set to 90 ° C., 110 ° C., and 120 ° C. from the upstream side. The gas composition of the drying air was set to a saturated gas concentration at −10 ° C. The average drying speed in the tenter dryer 35 was 120% by mass / min on a dry basis. The conditions of the drying zone were adjusted so that the amount of residual solvent in the film 82 was 7% by mass at the outlet of the tenter dryer 35. In the tenter dryer 35, the film was stretched in the width direction while being conveyed. In addition, when the width | variety of this wet film 74 before extending | stretching was 100%, it adjusted so that the width | variety after extending | stretching might become the value of Table 2. The draw ratio (tenter drive draw) from the peeling roller 75 to the entrance of the tenter dryer 35 was 1.02.

  The stretching ratio in the tenter dryer 35 is any two at a difference of 10% or less between each of the substantial stretching ratios at any two points at a position 10 mm or more away from the biting start position by the clip and at a distance of 20 mm. The difference in the stretching ratio of points was 5% or less. The stretching ratio here is (stretching ratio-1) X100. Further, the ratio of the length from the clip clamping start position to the clamping release position with respect to the length from the inlet to the outlet of the tenter dryer 35 was 90%. The solvent evaporated in the tenter dryer 35 was condensed and liquefied at a temperature of −10 ° C. and recovered. A condenser (condenser) was provided for condensation recovery, and the outlet temperature was set to -8 ° C. The condensed solvent was reused after adjusting the water content to 0.5% by mass or less. Then, the film was sent out from the tenter dryer 35 as a film 82.

  The ear-cutting device 40 cuts off both ends of the film 82 within 30 seconds from the exit of the tenter dryer 35. Ears 50 mm on both sides were cut with an NT type cutter, and the cut ears were blown to a crusher 90 with a cutter blower (not shown) and crushed into chips of about 80 mm 2 on average. This chip was used again as a raw material for dope production together with a cotton raw material powder as a raw material for dope preparation. The oxygen concentration in the drying atmosphere of the tenter dryer 35 was kept at 5 vol%. Note that the air was replaced with nitrogen gas in order to maintain the oxygen concentration at 5 vol%. Before drying at a high temperature in the drying chamber 41 described later, the film 82 was preheated in a predrying chamber (not shown) to which 100 ° C. drying air was supplied.

(3-9) Post-drying / static elimination The film 82 was dried in the drying chamber 41 at a high temperature. The drying chamber 41 was divided into four sections, and drying air of 120 ° C., 130 ° C., 130 ° C., and 130 ° C. was supplied from a blower (not shown) from the upstream side. The conveying tension of the film 82 by the roller 91 was set to 100 N / m, and the film was dried for about 10 minutes until the residual solvent amount finally reached 0.3% by mass. The wrap angle of the roller 91 (film winding center angle) was 90 degrees and 180 degrees. The material of the roller 91 was made of aluminum or carbon steel, and hard chrome plating was applied to the surface. The roller 91 has a flat surface shape and a blasted matte surface. The film position fluctuations due to the rotation of the roller 91 were all 50 μm or less. The roller deflection at a tension of 100 N / m was selected to be 0.5 mm or less.

  The solvent gas contained in the drying air was adsorbed and recovered using an adsorption recovery device 92. The adsorbent used here was activated carbon, and desorption was performed using dry nitrogen. The recovered solvent was reused as a dope preparation solvent with the water content adjusted to 0.3 mass% or less. The drying air contains plasticizers, UV absorbers and other high-boiling substances in addition to the solvent gas, so these were removed by a cooler and pre-adsorber to be removed by cooling and used for recycling. And adsorption / desorption conditions were set so that VOC (volatile organic compound) in the outdoor exhaust gas was finally 10 ppm or less. Moreover, the solvent amount collect | recovered by a condensation method among all the evaporation solvents was 90 mass%, and most of the remainder was collect | recovered by adsorption collection.

  The dried film 82 was conveyed to a first humidity control chamber (not shown). A drying air of 110 ° C. was supplied to the transition part between the drying chamber 41 and the first humidity control chamber. Air having a temperature of 50 ° C. and a dew point of 20 ° C. was supplied to the first humidity control chamber. Further, the film 82 was conveyed to a second humidity control chamber (not shown) that suppresses the curling of the film 82. In the second humidity control chamber, air of 90 ° C. and humidity of 70% was directly applied to the film 82.

(3-10) Knurling and Winding Conditions The film 82 after humidity control was cooled to 30 ° C. or lower in the cooling chamber 42 and then subjected to ear cutting at both ends again with an ear cutting device (not shown). A forced charge removal device (charge removal bar) 93 was installed so that the charged voltage of the film 82 during conveyance was always in the range of −3 kV to +3 kV. Further, knurling was applied to both ends of the film 82 by a knurling roller 94. The knurling is imparted by embossing from one side of the film 82, the width for imparting the knurling is 10 mm, and the knurling is pressed by the knurling roller 94 so that the height of the irregularities is 12 μm higher than the average thickness of the film 82. The pressure was set.

  Then, the film 82 was conveyed to the winding chamber 43. The winding chamber 43 was kept at a room temperature of 28 ° C. and a humidity of 70%. Inside the winding chamber 43, an ion wind static elimination device (not shown) was also installed so that the charged voltage of the film 82 was −1.5 kV to +1.5 kV. The product width of the film (thickness 80 μm) 82 thus obtained was 1475 mm. The diameter of the winding roller 95 was 169 mm. The tension pattern was such that the winding start tension was 300 N / m and the winding end was 200 N / m. The total winding length was 3940 m. The fluctuation range of winding deviation at the time of winding (sometimes referred to as oscillating width) was ± 5 mm, and the winding deviation period with respect to the winding roller 95 was 400 m. The pressing pressure of the press roller 96 against the winding roller 95 was set to 50 N / m. The temperature of the film 82 at the time of winding was 25 ° C., the water content was 1.4% by mass, and the residual solvent amount was 0.3% by mass. The average drying rate was 20% by mass / min on the basis of the dry weight throughout the entire process. Moreover, there was no winding looseness and wrinkles, and no winding slip occurred in the impact test at 10G. The roll appearance was also good.

  The film roll of the film 82 was stored in a storage rack at 25 ° C. and 55% RH for 1 month and further examined in the same manner as described above. As a result, no significant change was observed. Further, no adhesion was observed in the roll. Further, after the film 82 was formed, no peeling residue of the cast film 69 formed from the dope was observed on the cast band 34.

[Example 3: Production of polymer film by co-casting]
The polymer solutions shown below were prepared and used for the production of polymer films F44 to F51 together with the polymer solutions D1 to D3, matting agent dispersions M1 to M3, and retardation developer solutions C1 and C2 prepared in Example 2.

───────────────────────────────────────── Polymer solution (D5)
――――――――――――――――――――――――――――――――――――――――
Cellulose acylate listed in Table 4 100.0 parts by mass Triphenyl phosphate 7.9 parts by mass Biphenyl diphenyl phosphate 3.9 parts by mass Methylene chloride 344.9 parts by mass Alcohol having 6 or less carbon atoms 51.5 parts by mass ―――――――――――――――――――――――――――――――――――――――

――――――――――――――――――――――――――――――――――――――――
Polymer solution (D6)
────────────────────────────────────────
Cyclic polyolefin (P-1) 150.0 parts by mass Dichloromethane 462.7 parts by mass Methanol 69.1 parts by mass ────────────────────────── ──────────────
* "Alcohol having 6 or less carbon atoms" used for each film is shown in Table 4.

100 parts by mass of the polymer solution of the combination shown in Table 4, 1.35 mass of the matting agent dispersion, and a retardation developer solution were mixed so as to have the ratio shown in Table 4 to prepare a dope for film formation, and F44 It used for film preparation of -F51.
In solution casting film formation, a polymer film F44 was prepared under the same conditions as the polymer film F4. In addition, in the solution casting film formation, polymer films F45 to F51 were prepared under the same conditions as the polymer film F4 except that co-casting was used. Table 4 shows the composition of the dope used at this time.

[Example 4: Production of optical compensation film F26 having an optically anisotropic layer]
(Saponification treatment)
The film F3 produced in Example 1 was passed through a dielectric heating roll having a temperature of 60 ° C. to raise the film surface temperature to 40 ° C., and then an alkaline solution having the following composition was 14 ml / m ² using a bar coater. This was applied and allowed to stay under a steam far infrared heater (manufactured by Noritake Co., Ltd.) heated to 110 ° C. for 10 seconds, and then 3 ml / m ^{2 of} pure water was applied using the same bar coater. The film temperature at this time was 40 degreeC. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then the film was retained in a drying zone at 70 ° C. for 2 seconds and dried.

<Alkaline solution composition>
Potassium hydroxide 4.7 parts by weight Water 15.7 parts by weight Isopropanol 64.8 parts by weight Propylene glycol 14.9 parts by weight C ₁₆ H ₃₃ O (CH ₂ CH ₂ O) ₁₀ H (surfactant) 1.0 part by weight Part

(Formation of alignment film)
On the produced cellulose acetate film, a coating solution having the following composition was applied at 24 ml / m ² with a # 14 wire bar coater. The film was dried with warm air of 60 ° C. for 60 seconds and further with warm air of 90 ° C. for 150 seconds. Next, the longitudinal direction (conveying direction) of the cellulose acetate film was set to 0 °, and the formed film was rubbed in the clockwise direction of 135 °.

<Alignment film coating solution composition>
Denatured polyvinyl alcohol 40 parts by weight Water 728 parts by weight Methanol 228 parts by weight Glutaraldehyde (crosslinking agent) 2 parts by weight Citric acid ester (AS3, Sankyo Chemical Co., Ltd.) 0.69 parts by weight

(Formation of optically anisotropic layer)
On the alignment film, 41.01 kg of the following discotic liquid crystal compound, 4.06 kg of ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), cellulose acetate butyrate (CAB531-1, yeast) Manchemical Co., Ltd.) 0.29 Kg, Photopolymerization initiator (Irgacure 907, Ciba Geigy Co., Ltd.) 1.35 Kg, Sensitizer (Kayacure DETX, Nippon Kayaku Co., Ltd.) 0.45 Kg, Citrate ( Sankyo Chemical Co., Ltd. AS3) 0.1 kg of fluoroaliphatic group-containing copolymer (Megafac F780 manufactured by Dainippon Ink, Inc.) was added to a coating solution in which 0.45 kg was dissolved in 102 kg of methyl ethyl ketone, and # 2 .7 wire bar is rotated by 391 rotations in the same direction as the film transport direction, It apply | coated continuously on the orientation film | membrane surface of the film 15 currently conveyed at m / min. In the step of continuously heating from room temperature to 100 ° C., the solvent is dried, and then the film surface wind speed corresponding to the discotic liquid crystal compound layer is 1.5 m / sec in parallel with the film conveyance direction in the 135 ° C. drying zone. And heated for about 90 seconds to align the discotic liquid crystal compound. Next, the film is transported to a drying zone at 80 ° C., and an ultraviolet ray with an illuminance of 600 mW is applied by an ultraviolet irradiation device (ultraviolet lamp: output 160 W / cm, emission length 1.6 m) with the surface temperature of the film being about 100 ° C. Irradiation was carried out for 4 seconds to advance the crosslinking reaction, and the discotic liquid crystal compound was fixed to the orientation. Then, it was allowed to cool to room temperature and wound into a cylindrical shape to form a roll. Thus, the roll-shaped optical compensation film F26 was produced from the film F3 produced in Example 1 in this manner.

  The Re retardation value of the optically anisotropic layer measured at a wavelength of 633 nm using an ellipsometer (M-150, manufactured by JASCO Corporation) was 28 nm. Moreover, the average direction of the molecular symmetry axis of the optically anisotropic layer was 45.5 ° with respect to the longitudinal direction of the optical compensation film.

[Example 5: Production of optical compensation films F24 and F25 having optically anisotropic layers]
Using the films F14 and F15 prepared in Example 1, saponification treatment and alignment film preparation were performed in the same manner as in Example 4. Next, the longitudinal direction (conveying direction) of the cellulose acetate film was set to 0 °, and the formed film was rubbed in the clockwise 180 ° direction.

  On the alignment film, 91.0 kg of the above discotic liquid crystal compound, 9.0 kg of ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), cellulose acetate butyrate (CAB551-0.2, Eastman Chemical Co., Ltd.) 2.0 Kg, cellulose acetate butyrate (CAB531-1, Eastman Chemical Co., Ltd.) 0.5 Kg, photopolymerization initiator (Irgacure 907, Ciba Geigy Co.) 3.0 Kg, sensitizer ( Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) (1.0 kg) dissolved in 207 kg of methyl ethyl ketone, 0.4 kg of fluoroaliphatic group-containing copolymer (Megafac F780, manufactured by Dainippon Ink, Inc.) And transfer the film at # 391 wire bar with 391 rotations And is rotated in the same direction, was continuously coated on the orientation film surface of 20 m / min is being conveyed by the film F14 and F15. In the step of continuously heating from room temperature to 100 ° C., the solvent is dried, and then the film surface wind speed corresponding to the discotic liquid crystal compound layer is 5.0 m / sec in parallel with the film transport direction in the 135 ° C. drying zone. And heated for about 90 seconds to align the discotic liquid crystal compound. Next, the film is transported to a drying zone at 80 ° C., and an ultraviolet ray with an illuminance of 600 mW is applied by an ultraviolet irradiation device (ultraviolet lamp: output 160 W / cm, emission length 1.6 m) with the film surface temperature being about 100 ° C. Irradiation was carried out for 4 seconds to advance the crosslinking reaction, and the discotic liquid crystal compound was fixed to the orientation. Then, it was allowed to cool to room temperature and wound into a cylindrical shape to form a roll. In this manner, roll-shaped optical compensation films F24 and F25 were produced from the films F14 and F15 produced in Example 1, respectively.

  The Re retardation value of the optically anisotropic layer measured at a wavelength of 633 nm using an ellipsometer (M-150, manufactured by JASCO Corporation) was 45 nm. Moreover, the average direction of the molecular symmetry axis of the optically anisotropic layer was −0.3 ° with respect to the longitudinal direction of the optical compensation film.

(Evaluation of film properties)
About the polymer film produced in Examples 1-5, the sample for a measurement of seven places was cut out in the width direction in parallel with the film end surface, and the retardation in wavelength 590nm was measured using KOBRA 21ADH (Oji Scientific Instruments Co., Ltd. product). . Similarly, retardation from directions inclined by 40 ° and −40 ° from the normal to the film surface was measured, and Rth was calculated. The average values for the seven locations were defined as Re (590) and Rth (590) of this film. Moreover, the maximum height difference (P-V value) of the film thickness and the RMS value of the film thickness were measured by a FUJINON fringe analyzer (FX-03). At this time, the measurement area was in the range of φ = 60 mm. The orientation angle distribution was measured by OPTIPRO (XY scanning stage, halogen lamp light + 550 nm interference filter). At this time, the measurement area was 60 mm × 60 mm, and measurement was performed at intervals of 4 mm using a beam with a diameter of 3 mm. The results obtained in this experiment are shown in Tables 5 to 7, respectively.

[Example 6: Production of polarizing plate]
A polyvinyl alcohol (PVA) film having a thickness of 80 μm is dyed by immersing it in an aqueous iodine solution having an iodine concentration of 0.05% by mass at 30 ° C. for 60 seconds, and then in an aqueous boric acid solution having a boric acid concentration of 4% by mass. The film was vertically stretched to 5 times the original length while being immersed for 2 seconds, and then dried at 50 ° C. for 4 minutes to obtain a polarizing film having a thickness of 20 μm.
Polymer films F1, F2, F4 to F13, F16 to 26, and F27 to 51 produced in Examples 1 to 4 were attached to one side of a polarizer using a polyvinyl alcohol-based adhesive (TAC1 in FIGS. 4 to 6). Equivalent). 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 polymer 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 triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd .: equivalent to TAC2 in FIG. 5, TAC2-1 or 2-2 in FIG. 6) is saponified and polarized using a polyvinyl alcohol adhesive Affixed to the opposite side of the child and dried at 70 ° C. for 10 minutes or longer to produce polarizing plates P1 to P48.
The transmission axis of the polarizer and the slow axis of the polymer film produced in Examples 1 to 5 were arranged in parallel (FIG. 4). The transmission axis of the polarizer and the slow axis of the commercially available cellulose triacetate film were arranged so as to be orthogonal.
An acrylic adhesive was applied to the cell side surface of the polarizing plate prepared above, and a separate film was attached on the adhesive. A protective film was attached to the surface opposite to the cell.

[Example 7]
(Implementation to panel-1)
Polarizing plates P12 to P18 and P21 to P23 prepared in Example 6 on the front and back sides of the VA mode liquid crystal TV (LC-20C5-S, manufactured by Sharp Corporation) were peeled off and the retardation plates were peeled off. , P31 to 38 and P47 were pasted. In this case, the absorption axis of the polarizing plate on the viewing side is in the horizontal direction of the panel, the absorption axis of the polarizing plate on the backlight side is in the vertical direction of the panel, and the pressure-sensitive adhesive surface is on the liquid crystal cell side.

(Panel mounting-2)
VA mode liquid crystal TV (LC-20C5-S, manufactured by Sharp Corporation) is peeled off the front and back polarizing plates and retardation plates, and commercially available polarizing plates (HLC2-5618, Sanritz (No. The polarizing plates P1-11, P19, P20, P24-30, P39-46, and P48 produced in Example 6 were pasted on the back side. In this case, the absorption axis of the polarizing plate on the viewing side is in the horizontal direction of the panel, the absorption axis of the polarizing plate on the backlight side is in the vertical direction of the panel, and the pressure-sensitive adhesive surface is on the liquid crystal cell side.

(Panel mounting-3)
The polarizing plates on the front and back of the TN mode liquid crystal TV (LC-20V1, manufactured by Sharp Corporation) were peeled off, and polarizing plates P21 and 22 produced in Example 6 were attached. At this time, the directional relationship of each polarizing plate absorption axis was arranged to be the same as that on the market, and the pressure-sensitive adhesive surface was arranged on the liquid crystal cell side.

(Panel mounting-4)
The polarizing plates on the front and back of the OCB mode liquid crystal TV (VT23XD1, manufactured by Nanao Co., Ltd.) were peeled off, and the polarizing plate P23 produced in Example 6 was attached. At this time, the directional relationship of each polarizing plate absorption axis was arranged to be the same as that on the market, and the pressure-sensitive adhesive surface was arranged on the liquid crystal cell side.

The unevenness evaluation was performed by black display from the front. The evaluation was performed in the direction of front and azimuth angles of 45 °, 135 °, and polar angle of 10 °, and the ratings were as follows.
1: Haze-like unevenness is clearly visible and impractical, 3: Unevenness on the haze appears faint, but practically acceptable, 5: Unevenness is not visible at all 2, 4: Intermediate level

  The obtained results are shown in Tables 5-7. As described above, Re of each film is a value measured by making light with a wavelength of 590 nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments), and Rth is the Re, in-plane Retardation value measured by making light of wavelength 590 nm incident from a direction inclined + 40 ° with respect to the film normal direction with the slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis), and in-plane Retardation values measured in three directions, including retardation values measured by making light with a wavelength of 590 nm incident from a direction inclined by −40 ° with respect to the normal direction of the film with the slow axis as the tilt axis (rotation axis) Based on the average refractive index of cellulose acylate 1.48 or the average refractive index of cycloolefin polymer 1.53 and the input film thickness value OBRA 21ADH is a value calculated. Since F24 to F26 are obtained by applying an optically anisotropic layer having a different average refractive index on a cellulose acylate film, these values are not calculated.

  From Table 5, it can be seen that the film obtained by the present invention is superior to the comparative example in terms of black display unevenness.

  From Table 6, in the present invention, the films F27, F29, F31, F33, F35, F37, F39, F41, and F43 produced by increasing the alcohol concentration of the polymer solution before film formation are F4, F28, and F30. , F 32, F 34, F 36, F 38, F 30, and F 42, it can be seen that the black display unevenness is much better.

  From Table 7, it can be seen that in the present invention, the films F45 to 51 produced by the co-casting method are more excellent in terms of black display unevenness than F44.

It is an example of the schematic of the film manufacturing line for enforcing the solution casting method of this invention. It is a principal part enlarged view of FIG. It is other embodiment of how to apply dry air for implementing the solution casting method of the present invention. It is a schematic diagram which shows an example of the bonding method of the polymer film at the time of manufacture of the polarizing plate of this invention. It is sectional drawing which shows typically an example of the cross-sectional structure of the polarizing plate of this invention. It is sectional drawing which shows typically an example of the cross-section of the liquid crystal display device of this invention.

Explanation of symbols

20 Film Production Line 21 Stock Tank 22 Dope 30 Filtration Device 31 Casting Die 32 Rotating Roller 33 Rotating Roller 34 Casting Band 35 Tenter Type Dryer 40 Ear Clipping Device 41 Drying Chamber 42 Cooling Chamber 43 Winding Chamber 46 Casting Band 50 Labyrinth Seal 51 Air supply device 52a, 52b Nozzle 53 for applying drying air to the center of casting film 69 at both edges of casting film 69 The drying air is applied to both edges of the central part in the width direction of casting film 69 nozzle
54 Nozzle 55 for Applying Drying Air to Casting Film 69 toward Suction Port 55 Suction Port 57 Drying Air 60 Motor 61 Stirrer 62 Pump 63 Heat Transfer Medium Circulating Device 64 Casting Chamber 65 Temperature Control Facility 66 Condenser (Condenser)
67 Recovery Device 68 Decompression Chamber 69 Casting Film 69a Initial Films 70, 71, 72 Other Blowing Ports 73 Quick Drying Blowing Ports 73a Multiple Nozzles 76 Decompression Devices (eg, Roots Type Blower)
80 Crossing part 81 Blower 82 Film 90 Crusher 91 Numerous rollers 92 Adsorption / recovery device 93 Forced static elimination device (static elimination bar)
94 Knurling roller 95 Winding roller 96 Press roller A Successive wind area

Claims (31)

  A polymer film having a maximum difference in film thickness within a range of 60 mm in diameter with respect to an arbitrary point in the film of 1 μm or less.   A polymer film characterized in that an RMS value of a film thickness within a range of 60 mm in diameter is 0 μm to 0.15 μm centering on an arbitrary point in the film.   A polymer film, wherein a difference between a maximum value and a minimum value of an orientation angle in an arbitrary 60 mm × 60 mm square in the film is 0 ° to 0.40 °.   3. The polymer film according to claim 1, wherein a difference between a maximum value and a minimum value of an orientation angle in an arbitrary 60 mm × 60 mm square in the film is 0 degree to 0.40 degree. The front retardation Re ₍ λ ₎ is 0 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm, and the retardation Rth ₍ λ _{) in} the film thickness direction is 60 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm. The polymer film described in 1.
[Where Re ₍ λ ₎ is the front retardation (Re) value (unit: nm) at wavelength λnm, and Rth ₍ λ ₎ is the retardation (Rth) value (unit: nm) in the film thickness direction at wavelength λnm. .   The polymer film according to claim 1, comprising at least one retardation developer composed of a rod-like or discotic compound.   The polymer 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 polymer film in any one of Claims 1-7 characterized by the above-mentioned.   The polymer film according to any one of claims 1 to 8, wherein a raw material polymer of the polymer film is a cyclic polyolefin.   9. The raw material polymer of the polymer film is a cellulose ester, wherein the acyl substituent is substantially composed of only an acetyl group, and the total substitution degree is 2.56 to 3.00. The polymer film according to any one of the above.   The acyl substituent is substantially composed of at least two kinds of an acetyl group, a propionyl group, and a butanoyl group, and the total substitution degree is 2.50 to 3.00. The cellulose ester film as described. A cellulose acylate film 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 determined. DS2, when the substitution degree of the hydroxyl group at the 3-position with an acyl group is DS3, and the substitution degree with the acyl group of the hydroxyl group at the 6-position is DS6, the following formulas (I) and (II) are satisfied: Item 11. The cellulose ester film according to Item 10.
(I): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
(II): DS6 / (DS2 + DS3 + DS6) ≧ 0.315   A dope containing a polymer and a solvent is cast on a support that runs endlessly from a casting die, a cast film is formed from the dope on the support, and the dope is cast on the support after being cast. A solution casting method comprising a step of applying a dry air of 3 m / s or more to a casting membrane from within a second, and a step of peeling the casting membrane as a film, wherein the casting membrane is peeled from the support as a film Then, a solution film-forming method is provided, wherein a step of stretching the film is provided.   Casting a dope containing a polymer and a solvent from a casting die onto a support that runs endlessly, forming a casting film from the dope on the support, and stripping the casting film as a film In the membrane method, an initial film that forms the film formation start film is formed on the surface of the casting film, and the surface shape of the surface of the casting film is smoothed by a leveling effect of the initial film. A film forming method, comprising the step of stretching the film after peeling the cast film from the support as a film.   The solution casting method according to claim 14, wherein the initial film is formed by applying dry air to the casting film.   The wind drifting on the surface of the casting film is less than 3 m / s before the drying wind hits the casting film, and the time for which the wind drifts is 15 seconds or less. The solution casting method according to any one of -15.   The solution casting method according to any one of claims 13 to 16, wherein a wind speed of the dry air is 3 m / s or more and 15 m / s or less.   The solution casting method according to claim 13, wherein the drying air is applied to the casting film for 20 seconds or more.   The solution casting method according to any one of claims 13 to 18, wherein a gas concentration of the dry air is 25% or less.   The solution casting method according to any one of claims 13 to 19, wherein the temperature of the drying air is 40 ° C or higher and 150 ° C or lower.   The organic solvent in a polymer solution (hereinafter referred to as dope) before film formation contains 0.1% by mass or more and 40% by mass or less of an alcohol having 6 or less carbon atoms. Solution casting method. In the solution casting method, a film forming method of casting at least two layers of inner and outer layers by co-casting, the solid concentration of the dope of the outer layer, 1 mass% from the solids concentration of the inner layer of doped The solution casting method according to any one of claims 13 to 21, wherein the concentration is low.   In the solution casting method, at least two layers of the inner layer and the outer layer are cast by co-casting, and the amount of the dope alcohol added to the outer layer is 1.05 to 6.0 times that of the inner layer. The solution casting method according to claim 13, wherein the solution casting method is provided.   24. A film forming method in which at least two layers of an inner layer and an outer layer are cast by co-casting, wherein the addition amount of the matting agent fine particles in the inner layer is lower than that in the outer layer. The solution casting method according to claim 1.   The solution casting method according to any one of claims 13 to 24, wherein a draw ratio is 1.01 to 2.0 times.   The polymer film according to any one of claims 1 to 12, which is produced by the solution casting method according to any one of claims 13 to 25.   27. A polymer film comprising an optical compensation layer on the polymer film according to any one of claims 1 to 12 and claim 26.   28. The polymer film according to claim 27, wherein the optical compensation layer is a discotic liquid crystalline compound.   A polarizing plate using at least one of the polymer films according to any one of claims 1 to 12 and claims 26 to 28 as a protective film for a polarizer.   30. The polarizing plate according to claim 29, 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.   A liquid crystal display device using at least one of the polymer film according to any one of claims 1 to 12 and claims 26 to 28 and the polarizing plate according to claim 29 or 30.

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