JP2007083507A - Dispersion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion apparatus the maintenance labor for which can be reduced. <P>SOLUTION: The free rotatable first rotor 144 is arranged in the dispersion chamber 132, and on the upper faces of this first rotor 144 the agitating blades 146 are attached. On the outside of the dispersion chamber 132 the second rotor 148 is arranged so as to face through the chamber wall of the dispersion chamber 132 oppositely to the first rotor 144. The rotors 144 and 148 are each composed of a disk-shaped permanent magnet in which S poles and N poles are alternately formed along the rotational direction of the first rotor 144, and coupled together by magnetism. By rotating the second rotor 148 by the motor 152 and transferring this driving force to the first rotor 144, the agitating blades 146 are revolved. Because the agitating blades are rotated without recourse to an axis penetrating the chamber wall of the dispersion chamber, there is no need of installing a packing to prevent the leakage of the dispersion liquid, and therefore time and labor for maintenance can be saved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dispersion apparatus in which a polymer and a solvent are charged into a dispersion chamber provided with a stirring blade, and the stirring blade is rotated to disperse the polymer in the solvent.

  As a method for forming an optical polymer film such as a cellulose acylate film, a solution film forming method is known. In the solution casting method, after a polymer is dispersed in a solvent, the polymer is dissolved in the solvent to form a dope, and this dope is cast from a die onto a metal support such as a rotating band or drum. Produces a cast film. Then, the cast film is dried and peeled when it has a self-supporting property to obtain a belt-like film.

  When dispersing the polymer in the solvent, a dispersing device is used (for example, see Patent Document 1 below). The dispersion device continuously introduces a polymer and a solvent into a dispersion chamber provided with a stirring blade, and rotates the stirring blade to disperse the polymer in the solvent to generate a dispersion. The dispersion is discharged from the discharge unit. Discharge. Driving means such as a motor is provided outside the dispersion chamber, and the stirring blade is rotationally driven by this motor. The stirring blade and the motor are connected by a shaft penetrating the chamber wall of the dispersion chamber, and the rotation of the motor is transmitted to the stirring blade through this shaft. A seal mechanism such as an oil seal or a mechanical seal is provided between the shaft and the dispersion chamber so that the dispersion liquid does not leak from the dispersion chamber. As a material for the sealing mechanism, a fluorinated resin such as nitrile rubber, fluororubber, silicone rubber, ethylene propylene rubber, or tetrafluorinated ethylene resin is usually used.

Further, since the dispersion apparatus has a risk of explosion if the oxygen concentration in the dispersion chamber is high, the air in the dispersion chamber is replaced with nitrogen gas or the like. Furthermore, when the produced dispersion liquid is discharged from the discharge portion and the dispersion chamber is in a reduced pressure state, air containing oxygen enters from the powder hopper, and the risk of explosion increases. Therefore, in order to prevent this, it is necessary to continuously supply nitrogen to the dispersion chamber and the hopper.
JP 2005-097378 A

  However, the conventional dispersion device deteriorates the sealing material due to factors such as friction caused by the rotation of the motor, swelling due to organic solvents, deterioration, or aging. There was a problem such as. In addition, there are problems in that the cost for continuously sending nitrogen gas into the dispersion chamber and the cost for recovering the solvent from the exhaust nitrogen containing the solvent are incurred.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a dispersion apparatus that can reduce the labor required for maintenance. Another object of the present invention is to provide a dispersion apparatus that can reduce the cost required for operation.

  In order to achieve the above object, a dispersion apparatus according to the present invention is disposed in a dispersion chamber, and is connected to a stirring blade to rotate integrally with the rotor, and the outside of the dispersion chamber so as to face the rotor across the chamber wall of the dispersion chamber. And a rotor driving means for rotationally driving the rotor by magnetic force.

  In the rotational driving method using magnetic force, for example, magnetic poles having different polarities along the rotation direction of the rotor are alternately formed on each of the facing surfaces where the rotor and the rotor driving means face each other, and the magnetic poles formed by the rotor driving means There is a method of rotating the rotor by shifting the position in the rotation direction of the rotor. However, the magnetic pole arrangement method is not limited to this example. In addition, the rotor is preferably connected to a rotating shaft standing in the dispersion chamber via a bearing and is rotatably held. The bearing is preferably a non-magnetic material. An example of the material of the nonmagnetic material is ceramic.

  In addition, a gas circulation passage connecting the vicinity of the discharge portion where the dispersion liquid in which the polymer is dispersed in the solvent is discharged and the dispersion chamber, and a gas circulation passage inserted into the gas circulation passage, the flow rate of the gas passing through the gas circulation passage is changed. It is preferable to provide pressure adjusting means for controlling the pressure in the vicinity of the discharge portion and the pressure in the dispersion chamber.

  It is preferable to keep the pressure in the dispersion chamber in the range of −5000 Pa to −10 Pa. Moreover, it is preferable to maintain the pressure in the vicinity of the discharge part in a range of −2000 Pa to 2000 Pa. Further, it is preferable that a mixer for further mixing the dispersion liquid is provided in the vicinity of the discharge portion, and the mixer and the dispersion chamber are connected by the gas circulation passage.

  According to the present invention, since the stirring blade disposed in the dispersion chamber is rotated by magnetic force from the outside of the dispersion chamber, the driving force of the motor is transmitted to the stirring blade without providing a shaft that penetrates the chamber wall of the dispersion chamber. Since it is not necessary to provide a packing for preventing the dispersion liquid from leaking out from the dispersion chamber, maintenance work can be saved.

  Also, since the gas is sent from the vicinity of the discharge portion that is in a pressurized state as the dispersion liquid is discharged to the dispersion chamber that is in the reduced pressure state as the dispersion liquid is discharged, the gas is circulated in the dispersion device. Compared with the case where new gas is sent from the outside to the dispersion chamber, the cost can be reduced.

  Hereinafter, a dope production line for producing a raw material dope using the disperser of the present invention, and a film production line for producing a film by a solution casting method using the raw material dope produced in this dope production line will be described. Do.

[material]
As the cellulose acylate, it is preferable to use a cellulose acylate in which the degree of substitution of the hydroxyl group of cellulose satisfies all of the following formulas (1) to (3).
(1) 2.5 ≦ A + B ≦ 3.0
(2) 0 ≦ A ≦ 3.0
(3) 0 ≦ B ≦ 2.9
In the formula, A and B represent the substitution degree of the acyl group substituted with the hydroxyl group of cellulose, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 to 22 carbon atoms. . In addition, it is preferable that 90 mass% or more of cellulose acylate uses 0.1 mm to 4 mm particles.

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group having 2 or more carbon atoms. The degree of acyl substitution means the ratio at which the hydroxyl group of cellulose is esterified at each of the 2-position, 3-position and 6-position (100% esterification has a substitution degree of 1).

  The total acyl substitution degree, that is, DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. Further, D6S / (DS2 + DS3 + DS6) is preferably 0.28 or more, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. Here, DS2 is the degree of substitution of the hydroxyl group at the 2-position of the glucose unit with an acyl group (hereinafter also referred to as “degree of acyl substitution at the 2-position”), and DS3 is the degree of substitution of the hydroxyl group at the 3-position with an acyl group (hereinafter, referred to as “acyl group”). DS6 is the substitution degree of the hydroxyl group at the 6-position with an acyl group (hereinafter also referred to as “acyl substitution degree at the 6-position”).

  Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more types of acyl groups are used, one of them is preferably an acetyl group. DSA + DSB where DSA is the total substitution degree of hydroxyl groups at the 2nd, 3rd and 6th positions with an acetyl group and DSB is the total substitution degree with an acyl group other than the acetyl group at the 2nd, 3rd and 6th hydroxyl groups. The value of is preferably 2.22 to 2.90, more preferably 2.40 to 2.88. The DSB is preferably 0.30 or more, particularly preferably 0.7 or more. Further, 20% or more of DSB is preferably a 6-position hydroxyl group substituent, more preferably 25% or more is a 6-position hydroxyl group substituent, more preferably 30% or more, and particularly 33% or more is 6%. It is preferably a hydroxyl group substituent. The cellulose acylate preferably has a substitution degree value at the 6-position of 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. . With these cellulose acylates, a solution having a preferable solubility (raw material dope) can be produced. In particular, in a non-chlorine organic solvent, a good solution can be produced. Furthermore, it becomes possible to produce a solution having a low viscosity and good filterability.

  The cellulose acylate may be obtained from either linter cotton or pulp cotton, but is preferably obtained from linter cotton.

  The acyl group having 2 or more carbon atoms of the cellulose acylate of the present invention may be an aliphatic group or an aryl group and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include propionyl group, butanoyl group, pentanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, iso-butanoyl group , T-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group 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.

  Solvents for preparing the raw material dope include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol). , Diethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (eg, tetrahydrofuran, methyl cellosolve, etc.). .

  A halogenated hydrocarbon having 1 to 7 carbon atoms and dichloromethane are preferably used. From the viewpoint of physical properties such as the solubility of cellulose acylate, the peelability of the cast film from the support, the mechanical strength of the film, and the optical properties of the film, an alcohol having 1 to 5 carbon atoms is added in addition to dichloromethane. It is preferable to mix one kind or several kinds. 2 mass%-25 mass% are preferable with respect to the whole solvent, and, as for content of alcohol, 5 mass%-20 mass% are more preferable. Examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, and a mixture thereof is also preferably used.

  Recently, a solvent composition not using dichloromethane has been proposed in order to minimize the influence on the environment. For this purpose, ethers having 4 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, and esters having 3 to 12 carbon atoms are preferable, and these are used by being appropriately mixed. These ethers, ketones and esters may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as a solvent. The solvent may have another functional group such as an alcoholic hydroxyl group. In the case of a 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.

  The details of cellulose acylate are described in Japanese Patent Application No. 2003-319673, [0141] to [0192], and can also be applied to the present invention. Similarly, additives such as solvents and plasticizers, deterioration inhibitors, ultraviolet absorbers, optical anisotropy control agents, dyes, matting agents, and release agents are also described in Japanese Patent Application No. 2003-319673 [0193] to [0531]. ] And is applicable to the present invention.

[Production of raw material dope]
FIG. 1 shows a raw material dope production line 10. In manufacturing the raw material dope, first, the valve 12 is opened from the solvent tank 11, and the solvent is sent to the dispersing device 13. Next, the cellulose acylate flakes or pellets contained in the hopper 14 are fed into the dispersing device 13 while being weighed. The additive solution is sent from the additive tank 15 to the dispersing device 13 by opening and closing the valve 16. The dispersion device 13 generates a swelling liquid in which the cellulose acylate is swollen in the solvent by dispersing and mixing the cellulose acylate in the solvent. As will be described in detail later, in the present invention, the disperser 13 is devised to improve maintenance and reduce costs.

  The swelling liquid generated by the dispersion device 13 is sent to the heating device 26 by the pump 25. The heating device 26 preferably uses a multi-tube heat exchanger, a spiral heat exchanger, a jacket-type static mixed heat exchanger, or the like. The pressure in the heating device 26 is monitored by a pressure sensor 180 and controlled to 0.5 to 2.0 MPa by a valve 182. A raw material dope is obtained by placing the swelling liquid under pressure and heating and dissolving cellulose acylate in a solvent. In this case, the temperature of the swelling liquid is preferably 30 ° C to 110 ° C. Moreover, the cooling dissolution method which cools swelling liquid to the temperature of -150 degreeC--10 degreeC can also be performed. Cellulose acylate can be sufficiently dissolved in a solvent by appropriately selecting a heating dissolution method and a cooling dissolution method. After the temperature of the raw material dope is set to 20 to 50 ° C. by the temperature controller 27, filtration is performed by the filtering device 28 to remove impurities in the raw material dope. The average pore diameter of the filtration filter of the filtration device 28 is preferably 100 μm or less. The filtration flow rate is preferably 50 L / hr or more. Further, the filtration flow rate may be increased or decreased in conjunction with the amount of the raw material dope 36 in the tank 30, or a part or the whole may be circulated before the pump 25 through the valve 184. Further, it is preferable that the filtration flow rate is kept above the upper limit value of the normal use flow rate range, and a part or all of the filtration flow rate is circulated before the pump 25 in order to prevent foreign matter trapped in the filtration device from flowing out due to flow rate fluctuations. The raw material dope after filtration is put into the stock tank 30 through the valve 29.

  The raw material dope can be used as a dope in the solution casting method. However, from the viewpoint of peelability from the casting support, it is preferable to reduce the cellulose acylate concentration to shorten the solvent drying time or to improve the film strength at the time of peeling. In that case, it is preferable to concentrate the raw material dope to a target concentration in the dispersing device 13 with a concentrating device. It is desirable to use a flash concentrator as the concentrator. The raw material dope filtered by the filtration device 28 is sent to the pump 200 through the valve 29, and sent to the heating device 202 by the pump 200, and heated to 60 to 120 ° C. The pressure in the heating device 202 is monitored by the pressure sensor 204 and controlled to 0.5 to 2.0 MPa by the valve 206. Then, the raw material dope is sent to the flash device 31, and a part of the solvent is evaporated in the flash device 31. The evaporated solvent is made liquid by a condenser (not shown), and then recovered by the recovery device 32. It is advantageous from the viewpoint of cost that the solvent is regenerated and reused as a solvent for preparing the raw material dope by the regenerator 33.

  The concentrated raw material dope is extracted from the flash unit 31 using the pump 34. Although the bubble removal in the raw material dope can be performed by flash concentration, the bubble removal in the raw material dope may be further performed as necessary. Defoaming may be performed by any known method, and examples thereof include an ultrasonic irradiation method and a vacuum degassing method. The raw material dope after defoaming is stored in the stock tank 30. At this time, the temperature of the raw material dope is preferably 20 to 50 ° C. Further, the stored raw material dope is removed by the filtration device 35 from the foreign matter that cannot be removed by the filtration device 28 and the skin and gel foreign matter generated in the stock tank 30 and sent to the film production line 40. It is done.

  In addition, about the raw material, the raw material, the dissolution method of the additive, the filtration method, the defoaming, and the addition method when manufacturing the raw material dope, it is described in detail in Japanese Patent Application No. 2003-31673 [0514] to [0608]. These can be applied to the present invention.

[Solution casting method]
FIG. 2 shows a film production line 40. A stirring blade 42 that is rotated by a motor 41 is attached to the stock tank 30. The material dope 36 is always made uniform by rotating the stirring blade 42. Connected to the stock tank 30 are an intermediate layer dope channel 43, a support surface dope channel 44, and an air surface dope channel 45. The raw material dope 36 is fed by pumps 46, 47, 48 provided in the respective flow paths 43, 44, 45. After being fed to the feed block 70 and merged, it is cast from the casting die 71 onto the casting band 72.

"Dope manufacturing process"
The intermediate layer additive 51 contained in the stack tank 50 is fed by the pump 52 and mixed with the raw material dope in the intermediate layer dope flow path 43 (hereinafter referred to as the intermediate layer raw material dope). . Thereafter, the mixture is stirred and mixed by a static mixer (static mixer, sulzer mixer (Sulzer), etc.) 53 to be uniform. Thereby, the dope for the intermediate layer is generated. In the intermediate layer additive 51, for example, a solution (or dispersion) containing an additive such as an ultraviolet absorber or a retardation control agent in advance is placed.

  The support surface additive 56 contained in the stock tank 55 is fed to the raw material dope (hereinafter referred to as support surface raw material dope) in the support surface dope channel 44 by a pump 57 and mixed. . Thereafter, the mixture is stirred and mixed by a static mixer (static mixer, sulzer mixer (Sulzer), etc.) 58 to be uniform. Thereby, the dope for the support surface is generated. The support surface additive 56 includes a peeling accelerator (e.g., citrate ester) that facilitates peeling from the casting band as the support, and the film surface between the film surfaces when the film is wound into a roll. Additives such as a matting agent (for example, fine particle powder such as silicon dioxide) for suppressing adhesion are contained in advance. The support surface additive 56 may contain additives such as a plasticizer and an ultraviolet absorber.

  The air surface additive 61 contained in the stock tank 60 is fed to the raw material dope in the air surface dope channel 45 (hereinafter referred to as air surface raw material dope) by the pump 62 and mixed. . Thereafter, the mixture is stirred and mixed by a static mixer (static mixer, sulzer mixer (Sulzer), etc.) 63 to be uniform. Thereby, the dope for air surfaces is produced | generated. The air surface additive 61 contains in advance additives such as a matting agent (for example, fine particle powder such as silicon dioxide) that suppresses adhesion between film surfaces when the film is wound into a roll. Yes. The air surface additive 61 may contain additives such as a peeling accelerator, a plasticizer, and an ultraviolet absorber.

  Each dope generated by adding various additives to each raw material dope is fed to the feed block 70 at a desired flow rate. After the dopes merge in the feed block 70, they are cast from the casting die 71 onto the casting band 72. The dope of each dope channel (intermediate layer, support surface, air surface) is not branched from the stock tank 30, but a stock tank is provided for each layer, and the dope is different in composition and type of cellulose acylate raw material. May be used.

"Casting process"
The material of the casting die 71 is preferably a double layer stainless steel. It is preferable to use a material having a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. Moreover, what has corrosion resistance substantially equivalent to SUS316 in the forced corrosion test in electrolyte aqueous solution can also be used. Further, a material having corrosion resistance that does not cause pitting (opening) at the gas-liquid interface even when immersed in a mixed solution of dichloromethane, methanol, and water for 3 months is used. Further, it is preferable that the casting die 71 is manufactured by grinding a material that has passed one month or more after casting. Thereby, the surface shape of the dope flowing in the casting die 71 is kept constant. It is preferable to use a finishing accuracy of the wetted surfaces of the casting die 71 and the feed block 70 in terms of surface roughness of 1 μm or less and straightness of 1 μm / m or less in any direction. The slit clearance that can be adjusted in the range of 0.5 mm to 5.0 mm by manual adjustment or automatic adjustment is used. About the corner | angular part of the liquid-contacting part of the lip | tip end of the casting die 71, R uses 50 micrometers or less over the full width of a slit. Moreover, it is preferable to use what was adjusted so that the shear rate in the casting die 71 might be set to 1 (1 / sec)-5000 (1 / sec).

  The width of the casting die 71 is not particularly limited, but it is preferable to use a casting die having a width of about 1.0 to 2.0 times the width of the final film. Further, during film formation, it is preferable to attach a temperature controller so as to be maintained at a predetermined temperature. The casting die 71 is preferably a coat hanger type. Furthermore, it is more preferable to provide a thickness adjusting bolt (heat bolt) at a predetermined interval and attach an automatic thickness adjusting mechanism using a heat bolt. It is preferable that the heat bolt is subjected to film formation by setting a profile according to the amount of pump 46 (preferably high precision gear pump) 46 to 48 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 forming line 40. It is preferable that the thickness difference between any two points except the casting edge is adjusted within 1 μm, and the maximum difference in the width direction thickness is adjusted to 3 μm or less. 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 tip of the lip. A method for forming the cured film is not particularly limited, and examples thereof include ceramic coating, hard chrome plating, and a nitriding method. In the case of using ceramics 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 71, and does not have adhesion to the dope. Specific examples include tungsten carbide (WC), Al ₂ O ₃ , TiN, Cr ₂ O _{3 and the} like, but it is particularly preferable to use WC. 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 71 from locally drying and solidifying, it is preferable to attach a solvent supply device (not shown) to the slit end. Supplying 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) to the gas-liquid interface between the end of the casting bead and the slit. Is preferred. In addition, it is preferable to use a pump having a pulsation rate of 5% or less for supplying the liquid.

  A casting band 72 is provided below the casting die 71 so as to span the rotating rollers 73 and 74. The casting band 72 travels endlessly as the rotating rollers 73 and 74 are rotated by a driving device (not shown). The moving speed of the casting band 72, that is, the casting speed is preferably 10 m / min to 200 m / min. In order to make the surface temperature of the casting band 72 a predetermined value, it is preferable that a heat transfer medium circulation device 75 is attached to the rotary rollers 73 and 74. The surface temperature of the casting band 72 is preferably −20 ° C. to 40 ° C. A heat transfer medium flow path is formed in the rotation rollers 73 and 74, and the temperature of the rotation rollers 73 and 74 is set to a predetermined value by passing through the heat transfer medium maintained at a predetermined temperature. Can hold.

  The width of the casting band 72 is not particularly limited, but it is preferable to use one having a range of 1.1 to 3.0 times the casting width of the dope. Moreover, it is preferable to use what was polished so that length may be 10 m-200 m, thickness may be 0.3 mm-10 mm, and surface roughness may be 0.05 micrometer or less. The material 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 a thickness unevenness of the entire casting band 72 of 0.5% or less.

It is preferable to adjust the tension generated in the casting band 72 when the rotary rollers 73 and 74 are driven to be 1.5 × 10 ⁴ kg / m. Further, the relative speed difference between the casting band 72 and the rotating rollers 73 and 74 is adjusted to be 0.01 m / min or less. The speed fluctuation of the casting band 72 is preferably 0.5% or less, and the meandering in the width direction that occurs when the casting band 72 rotates once is preferably 1.5 mm or less. In order to control this meandering, it is more preferable to provide a detector (not shown) for detecting both ends of the casting band 72 and perform feedback control based on the measured value. Furthermore, it is preferable to adjust so that the vertical position fluctuation accompanying the rotation of the rotary roller 73 on the surface of the casting band 72 immediately below the casting die 71 is 200 μm or less.

It is also possible to use the rotating rollers 73 and 74 directly as a support. In this case, it is preferable to rotate with high accuracy so that the rotation unevenness is 0.2% or less. In this case, it is preferable that the average roughness of the surfaces of the rotary rollers 73 and 74 is 0.01 μm or less. Therefore, chrome plating is performed to provide sufficient hardness and durability. In addition, it is necessary to suppress the surface defects of the support (the casting band 72 and the rotating rollers 73 and 74) to the minimum. Specifically, there are no pinholes of 30 μm or more, pinholes of 10 μm or more and less than 30 μm are 1 / m ² or less, and pinholes of less than 10 μm are preferably ² / m ² or less.

  The casting die 71, the casting band 72, etc. are accommodated in the casting chamber 76. A temperature control facility 77 is attached to keep the temperature in the casting chamber 76 at a predetermined value. It is preferable that the temperature of the casting chamber 76 is −10 ° C. to 57 ° C. Further, a condenser (condenser) 78 for condensing and recovering the volatile organic solvent is provided. The condensed and liquefied organic solvent is recovered and regenerated by the recovery device 79 and then reused as a dope preparation solvent.

  A casting film 80 is formed by co-casting a dope (air surface dope, intermediate layer dope, support surface dope) from the casting die 71 on the casting band 72 while forming a casting bead. In addition, it is preferable that the temperature of each dope at this time is -10 degreeC-57 degreeC. In order to stabilize the formation of the casting bead, the decompression chamber 81 is preferably attached to the rear surface of the casting bead and adjusted to a desired pressure. The back surface of the bead is preferably decompressed in the range of −10 Pa to −2000 Pa rather than the pressure with the front surface. Furthermore, in order to keep the temperature of the decompression chamber 81 at a predetermined temperature, it is preferable to attach a jacket (not shown). The temperature of the decompression chamber 81 is not particularly limited, but is preferably in the range of 10 ° C to 50 ° C. Further, it is preferable to attach a suction device (not shown) to the edge portion of the casting die 71 in order to have the desired shape of the casting bead. The edge suction air volume is preferably in the range of 1 L / min to 100 L / min.

  The casting film 80 moves as the casting band 72 travels. At this time, it is preferable to provide the blowers 82, 83, and 84 in order to evaporate the solvent in the casting film 80. Although the attachment position of the blower is illustrated as being provided on the upper upstream side 82, the downstream side 83, and the lower part 84 of the casting band 72, the present invention is not limited to this. Further, it is preferable that a wind shield device 85 is provided in order to suppress the surface variation of the film surface due to the drying air being blown onto the cast film 80 immediately after the formation. Although the figure shows an example in which a casting band is used as a support, a casting drum can also be used. The surface temperature of the casting drum is preferably -20 ° C to 40 ° C.

"Peeling and drying process"
After the casting film 80 has a self-supporting property, it is peeled off from the casting band 72 as a wet film 87 while being supported by a peeling roller 86. Thereafter, the transfer section 90 provided with a large number of rollers is conveyed and then fed into the tenter 100. In the transfer part 90, the drying of the wet film 87 is advanced by sending the drying air of desired temperature from the air blower 91. FIG. At this time, the temperature of the drying air is preferably 20 ° C to 250 ° C. In the crossover section 90, it is also possible to give the wet film 87 a draw by making the rotation speed of the downstream roller faster than the rotation speed of the upstream roller.

  The wet film 87 sent to the tenter 100 is dried while being transported with its both edges held by clips. Moreover, it is preferable to divide the inside of the tenter 100 into different temperature zones to adjust the drying conditions. Further, the wet film 87 may be stretched in the width direction in the tenter 100. In this case, it is preferable that at least one direction of the wet film 87 in the casting direction and the width direction is stretched by 0.5% to 300% by the crossing portion 90 and / or the tenter 100.

  Moreover, it is preferable to perform relaxation after stretching. The stretching and the relaxation are performed by gripping the film with gripping means, and when the both ends of the film are gripped, the width of the film is L1 (mm), and the film is stretched to the maximum in the width direction. 1 <(L2−L3) / L1 × 100 <15, where L2 (mm) is the width of the film and L3 (mm) is the width of the film when the gripping means releases the film by relaxing the film. It is preferable that Furthermore, when performing the stretching relaxation, it is preferable that the drying temperature of the film is maintained at substantially the same temperature in the range of 50 ° C. or higher and 180 ° C. or lower.

  The wet film 87 dried to a predetermined residual solvent amount by the tenter 100 is sent out as a film 101. Both edges of the film 101 are cut at both ends by the ear clip device 102. The cut film is sent to the crusher 103 by a cutter blower (not shown). The edge of the film is crushed by the crusher 103 into chips. It is advantageous in terms of cost to reuse this chip for dope preparation. In addition, although the process of cut | disconnecting the both edges of this film can also be abbreviate | omitted, it is preferable to carry out in either from the casting process to the process of winding up the film mentioned later.

  Next, the film 101 is sent to a drying chamber 105 provided with a large number of rollers 104. Although the temperature in the drying chamber 105 is not specifically limited, It is preferable that it is the range of 50 to 180 degreeC. In the drying chamber 105, the film 101 is conveyed while being wound around the roller 104, and the solvent is volatilized and dried. Further, an adsorption recovery device 106 is attached to the drying chamber 105. The volatile solvent is adsorbed and recovered by the adsorption recovery device 106. The air from which the solvent component has been removed is blown into the drying chamber 105 as dry air. The drying chamber 105 is more preferably divided into a plurality of sections in order to change the drying temperature. In addition, it is preferable to provide a preliminary drying chamber (not shown) between the ear clip device 102 and the drying chamber 105 to perform preliminary drying of the film 101 to suppress a rapid increase in the film temperature. By performing preliminary drying in this way, it is possible to prevent a change in the shape of the film accompanying a rapid increase in the film temperature.

  The film 101 is conveyed to the cooling chamber 107 and cooled to approximately room temperature. A humidity control chamber (not shown) may be provided between the drying chamber 105 and the cooling chamber 107. Air adjusted to the desired humidity and temperature of the film 101 is blown in the humidity control chamber. Thereby, it is possible to suppress the occurrence of curling of the film 101 and the occurrence of winding failure during winding.

  A forced charge removal device (charge removal bar) 108 is provided so that the charged voltage during the conveyance of the film 101 falls within a predetermined range (for example, −3 kV to +3 kV). In the figure, an example provided on the downstream side of the cooling chamber 107 is illustrated, but the position is not limited thereto. Further, it is preferable that a knurling roller 109 is provided to give knurling to both edges of the film 101 by embossing. In addition, it is preferable that the unevenness | corrugation of the knurled location is 1 micrometer-200 micrometers.

"Winding process"
Finally, the film 101 is taken up by the take-up roller 111 in the take-up chamber 110. At this time, it is preferable to wind the sheet while applying a desired tension with the press roller 112. More preferably, the tension is gradually changed from the start to the end of winding. The film 101 to be wound is preferably at least 100 m in the longitudinal direction (casting direction). Further, the width direction is preferably 600 mm or more, and more preferably 1400 mm or more and 1800 mm or less. Also, it is effective when it is larger than 1800 mm.

  As described above, since the three types of dopes are co-cast in the present embodiment, the intended characteristics of the film 101 can be easily obtained. That is, when winding the film 101 as a roll, it is necessary to prevent adhesion between the film surfaces. Therefore, it is preferable to add a matting agent in the dope, but the matting agent usually causes deterioration of optical properties (for example, deterioration of transparency). Therefore, as in this embodiment, the matting agent is contained in the dope for the support surface and the dope for the air surface, which are the front and back surfaces of the film, and is not included in the dope for the intermediate layer. It is possible to obtain the optical characteristics.

  For co-casting, as in the above-described embodiment, simultaneous lamination co-casting in which two or more types of dopes are cast at the same time, and sequential lamination co-casting in which two or more types of dopes are cast in order from the lower layer side. The present invention can be applied to any of these. Moreover, you may combine these both casting. Moreover, when performing casting, the casting die 71 which attached the feed block 70 as shown in FIG. 2 may be used, and a multi-manifold type casting die may be used. It is preferable that the thickness of the layer on the air surface side and / or the thickness of the layer on the support side is 0.5% to 30% in the total film thickness of the film composed of multiple layers by co-casting. Furthermore, when performing simultaneous lamination co-casting, it is preferable to enclose the high-viscosity dope with the low-viscosity dope when casting the dope from the die slit to the support. Moreover, when performing simultaneous lamination co-casting, it is preferable that the dope inside is encapsulated with a dope having a higher alcohol composition ratio than the dope when the dope is cast from the die slit to the support.

  From casting die, decompression chamber, support structure, co-casting, peeling method, stretching, drying conditions of each process, handling method, curl, winding method after flatness correction, solvent recovery method, film recovery method The details are described in Japanese Patent Application No. 2003-319673 [0610] to [0842]. These descriptions are also applicable to the present invention.

[Performance / Measurement method]
(Curl degree / thickness)
The performance of the wound cellulose acylate film and the measuring method thereof are described in Japanese Patent Application No. 2003-319673 [0113] to [0140]. These are also applicable to the present invention.

[surface treatment]
It is preferable that at least one surface of the cellulose acylate film is surface-treated. The surface treatment is preferably at least one of vacuum glow discharge treatment, atmospheric pressure plasma discharge treatment, ultraviolet irradiation treatment, corona discharge treatment, flame treatment, acid treatment or alkali treatment.

[Functional layer]
(Antistatic, hardened layer, antireflection, easy adhesion, antiglare)
At least one surface of the cellulose acylate film may be undercoated.

  Further, it is preferable to use the cellulose acylate film as a base film as a functional material provided with another functional layer. The functional layer is preferably provided with at least one layer selected from an antistatic layer, a cured resin layer, an antireflection layer, an easy adhesion layer, an antiglare layer and an optical compensation layer.

The functional layers preferably contain at least one surfactant 0.1mg / m ² ~1000mg / m ² containing. Moreover, it is preferable that the said functional layer contains 0.1 mg / m2-1000 mg / m < ² > of at least 1 type of slip agent. Further, the functional layers preferably contain at least one sort of matting agents in the 0.1mg / m ² ~1000mg / m ² containing. Further, the functional layers preferably contain at least one sort of antistatic agents 1mg / m ² ~1000mg / m ² containing. In addition to the above, the method for applying the surface-treated functional layer to the cellulose acylate film for realizing various functions and properties is described in detail in [0843] to [1079] of Japanese Patent Application No. 2003-319673. , Including methods. These are also applicable to the present invention.

(Use)
The cellulose acylate film thus formed is particularly useful as a polarizing plate protective film used in a liquid crystal display device. Japanese Patent Application No. 2003-319673 describes in detail examples of using a cellulose acylate film for TN type, STN type, VA type, OCB type, reflective type, and other liquid crystal display devices. The application also describes a cellulose acylate film provided with an optically anisotropic layer and a cellulose acylate film provided with antireflection and antiglare functions. Furthermore, the same application also describes an example in which a biaxial cellulose acylate film imparted with appropriate optical performance is used as an optical compensation film, and the formed cellulose acylate film can be used for various applications. it can.

  Although the cellulose acylate film has been described as an example, the present invention can also be applied to a polymer film using a polymer other than cellulose acylate as a dope raw material. The polymer film is preferably an optical film. The polymer film is preferably a cellulose ester film. The cellulose ester film is preferably a cellulose acylate film, more preferably a cellulose acetate film, and most preferably a cellulose triacetate film. Moreover, what uses the said cellulose-ester film for various optical functional films is also contained in this invention. For example, a photographic material base film, a polarizing plate protective film, an optical compensation film base film, and the like. Furthermore, the present invention includes a liquid crystal display device configured using the optical functional film. The present invention also includes a polymer film produced by a melt film forming method.

  The film thus formed may have an axial deviation of less than 2.0 degrees between the slow axis of an arbitrary region of the film and the slow axes of all regions adjacent to the arbitrary region. preferable. In addition, it is more preferable that the axial deviation is less than 1.0 degree. Furthermore, the present invention can also be applied when manufacturing a thin film having a film thickness of 15 μm or more and 100 μm or less.

  Hereinafter, the dispersing device 13 according to the present invention will be described in detail. As shown in FIG. 3, the dispersion apparatus 13 is provided with a dispersion chamber 132 in the main body 130, and cellulose acylate, a solvent, and an additive are charged into the dispersion chamber 132. Cellulose acylate is introduced into the dispersion chamber 132 from an introduction pipe 134 that penetrates the top surface of the dispersion chamber 132. On the other hand, the solvent and the additive are sent to the tank 138 provided so as to surround the side portion of the dispersion chamber 132 through the liquid feeding pipe 136. The upper part of the tank 138 is formed so as to be connected to the dispersion chamber 132, and the sent solvent and additive are stored in the tank 138 in a certain amount and then overflowed into the dispersion chamber 132. The side wall of the dispersion chamber 132 is formed in a mortar shape, and the solvent and additive overflowing from the tank 138 are introduced into the central portion of the dispersion chamber 132 through this side wall. In addition, a part of the solvent and a part of the additive may be directly charged below the dispersion chamber 182.

  A cylindrical rotor support shaft 140 is erected on the lower surface of the dispersion chamber 132, and the first rotor 144 is rotatably attached to the rotor support shaft 140 via a bearing 142. The first rotor 144 is formed in a disk shape (see FIG. 4), and a plurality of stirring blades 146 are provided on the peripheral surface thereof. The stirring blade 146 rotates with the rotation of the first rotor 144 to disperse the cellulose acylate in the solvent. The dispersion chamber 132 is provided with a lubricating liquid passage 208 for supplying a lubricating liquid such as oil or solvent into the bearing 142 so that the first rotor 144 can smoothly rotate. The bearing 142 is preferably a non-metallic one, and particularly preferably a high-strength ceramic bearing.

  A second rotor 148 is disposed below the dispersion chamber 132. The second rotor 148 is formed in the same disk shape as the first rotor 144, and is disposed so as to face the first rotor 144 across the chamber wall of the dispersion chamber 132. The second rotor 148 is directly connected to a drive shaft 150 by a motor 152 and is driven to rotate by the motor 152. In this embodiment, the first rotor 144 is rotated by the rotation of the second rotor 148.

  For this reason, as shown in FIG. 4, both the first rotor 144 and the second rotor 148 are composed of permanent magnets that alternately form S poles and N poles along the rotational direction. By doing so, the S pole of the first rotor 144 and the N pole of the second rotor 148, and the N pole of the first rotor 144 and the S pole of the second rotor 148 are attracted to each other. Rotate together. Thereby, by rotating the second rotor 148 by the motor 152, this driving force is transmitted to the first rotor 144, and the first rotor 144 rotates. And the stirring blade 146 rotates with rotation of the 1st rotor 144, a cellulose acylate is disperse | distributed in a solvent, and a dispersion liquid is produced | generated. Due to the rotation of the second rotor 148, heat is generated due to overcurrent at the bottom surface of the chamber wall of the dispersion chamber 132. Therefore, a cooling water channel 209 is provided at the bottom of the dispersion chamber 132 to perform cooling.

  The dispersion is discharged from a discharge port 154 (see FIG. 3) provided on the side of the first rotor 144 and sent to the mixer 156. As the mixer 156, for example, a shear type mixer is used, and the dispersion is further sufficiently mixed while passing through the mixer 156. In this way, the cellulose acylate passes through the dispersing device 13 and is dispersed and mixed, so that the cellulose acylate swells in the solvent and a swelling liquid is generated. The mixer 156 may be a tank type stirring device. The tank may be continuously discharged or a batch type in which storage and discharge are completely repeated.

  In the process of generating the swelling liquid, if the oxygen concentration is high, there is a risk of explosion. Therefore, the dispersion chamber 132 and the mixer 156 are filled with nitrogen gas from the tank (not shown) through the valve 210. However, the vicinity of the discharge port 154 and the inside of the mixer 156 are in a pressurized state due to the discharge pressure from the discharge port 154 and the swelling of cellulose acylate. Further, when the dispersion liquid is discharged from the discharge port 154, the dispersion chamber 132 is decompressed, and the outside air containing oxygen is drawn into the dispersion chamber 132, increasing the risk of explosion.

  Therefore, in the dispersion device 13, the pressure and oxygen concentration in the dispersion chamber 132 are monitored by the pressure sensor 212 and the oxygen sensor 214, and the gas circulation passage 160 and the pressure control valve 162 are provided. Based on the pressure and the oxygen concentration, the pressure in the mixer 156 and the dispersion chamber 132 is controlled. The gas circulation passage 160 is composed of a pipe that connects the mixer 156 and the dispersion chamber 132, escapes the gas in the mixer 156 that is in a pressurized state, and supplies the escaped gas to the dispersion chamber 132 that is in a decompressed state. The pressure control valve 162 is inserted into the gas circulation passage 160 and changes the flow rate of the gas passing through the gas circulation passage 160. By operating the pressure control valve 162, the pressure in the spacer 156 and the dispersion chamber 132 can be controlled. At this time, it is preferable to keep the pressure in the mixer 156 in the range of −2000 Pa to 2000 Pa. Moreover, it is preferable to maintain the pressure of the dispersion chamber 132 in the range of −5000 Pa to −10 Pa. Further, in order to control the pressure of the mixer 156, a pressure sensor 220 for monitoring the pressure in the mixer 156 and a valve 222 for adjusting the discharge amount of the gas in the mixer 156 are provided. The pressure in mixer 156 is monitored by pressure sensor 220 and controlled by valve 222. The gas discharged through the valve 222 is sent to the recovery device.

  As described above, since the dispersion device 13 is configured to transmit the driving force of the motor to the stirring blade by magnetic force and rotate, the driving force is transmitted to the stirring blade by the shaft passing through the chamber wall of the dispersion chamber. In comparison, it is not necessary to provide a packing for preventing the dispersion liquid from leaking out from the periphery of the shaft, and labor for maintenance can be saved.

  In addition, since the gas in the mixer that is in a pressurized state is supplied to the dispersion chamber that is in a reduced pressure state, the mixer can be prevented from being excessively pressurized and can be smoothly swelled. It is possible to prevent the problem that the outside air enters due to the reduced pressure state. Furthermore, since the gas is circulated in the dispersion apparatus, the cost can be reduced as compared with the case where the gas is sent from the outside of the dispersion apparatus in order to avoid decompression of the dispersion chamber.

  In the above embodiment, the second rotor is made of a permanent magnet, and the first rotor is rotated by rotating the second rotor. However, the present invention is not limited to this. For example, an electromagnet may be used instead of the second rotor. In this case, an electromagnet that alternately forms S and N poles along the rotation direction of the first rotor by energization is used. Then, the energization direction to the electromagnet may be repeatedly reversed so that the positions of the S pole and the N pole are shifted in the rotation direction of the first rotor. Of course, an electromagnet that alternately forms S poles and N poles along the rotation direction of the first rotor may be used, and the electromagnets themselves may be rotationally driven. Even if it is such a structure, the effect similar to the said embodiment can be acquired.

  Furthermore, in the above embodiment, the example in which the mixer is provided immediately after the disperser has been described, but the mixer may be provided at a position away from the disperser. Further, since the polymer swells even when passed through a disperser, the present invention can be carried out without providing a mixer. As described above, when the mixer is separated from the disperser or when the mixer is not provided, the vicinity of the discharge port of the disperser and the dispersion chamber may be connected by the gas circulation passage. Further, although an example has been described in which gas is circulated in the dispersing device, in addition to this, new gas may be sent from the outside of the dispersing device. Furthermore, in consideration of cost, it is preferable to provide a gas circulation passage and circulate the gas in the dispersion apparatus, but the present invention can be implemented without providing the gas circulation passage.

  In order to perform more stable dispersion, a jacket may be provided so as to wrap the dispersion apparatus, and the temperature of the dispersion apparatus may be kept constant. In this case, it is preferable to adjust the temperature in the dispersion device 13 in the range of -10 ° C to 55 ° C. Furthermore, in the above-described embodiment, the dispersion apparatus using the anchor-shaped stirring blade has been described as an example. However, the present invention can be applied to various dispersion apparatuses such as a dissolver type eccentric dispersion apparatus. Various conditions in the process of producing the dispersion, such as the amount of cellulose acylate introduced, the flow rate of the solvent, and the shear rate by the stirring blade, are described in detail in Japanese Patent Application No. 2003-331178. It can also be applied.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

The used mass part is shown below.
[composition]
Cellulose triacetate (acyl group substitution degree 2.84, viscosity average degree of polymerization 306, water content 0.2 mass%, viscosity 315 mPa · s in 6 mass% dichloromethane solution, average particle diameter 1.5 mm, standard deviation 0 Powder of 0.5 mm) 100 parts by mass dichloromethane (first solvent) 320 parts by mass methanol (second solvent) 83 parts by mass 1-butanol (third solvent) 3 parts by mass triphenyl phosphate (plasticizer A) 6 parts by weight diphenyl phosphate (plasticizer B) 3.8 parts by weight

[Cotton compound]
The cellulose triacetate used here has a residual acetic acid content of 0.1% by mass or less, a Ca content of 58 ppm, a Mg content of 42 ppm, a Fe content of 0.5 ppm, a free acetic acid of 40 ppm, It contained 15 ppm of sulfate ions. The degree of substitution of the 6-position acetyl group was 0.91, 32.5% of the total acetyl. The acetone extract was 8% by mass, and the weight average molecular weight / number average molecular weight ratio was 2.5. The yellow index is 1.7, the haze is 0.08, the transparency is 93.5%, the Tg (glass transition temperature; measured by DSC) is 160 ° C., and the crystallization heat generation is 6.4 J / g. Met. This cellulose triacetate was synthesized from cellulose collected from cotton as a raw material.

(1) Raw material dope preparation The raw material dope production line 10 shown in FIG. 1 was used. Moreover, the stirring blade 146 was rotated by the magnetic force from the outside of the dispersion chamber 132 using the dispersion apparatus 13 (see FIG. 3) of the present invention. As the dispersing device 13, a stainless steel body was used. A ceramic bearing (NCT3208PT) manufactured by Koyo Seiko was used as the bearing 136 disposed between the rotor support shaft 140 and the first rotor 144. Then, the cellulose triacetate powder (flakes) is gradually added from the hopper 14 while the plurality of solvents are mixed and stirred and dispersed as a mixed solvent by the dispersing device 13, so that the dispersion flow rate becomes 200 kg per minute. Prepared. In addition, all the solvents used that the water content is 0.5 mass% or less. The stirring blade 146 was dispersed at a peripheral speed of 1 m / sec (shear stress 1 × 10 ⁴ kgf / m / sec ² ). The temperature of the dispersion was 25 ° C. Thereafter, the peripheral speed of the anchor blade 19 was set to 0.5 m / sec, and the mixture was further stirred for 100 minutes, and the produced dispersion was sent to the mixer 156 to obtain a swelling liquid in which cellulose triacetate flakes were swollen. The pressure control valve 162 was operated to control the pressure in the dispersion chamber 132 in the range of −5000 Pa to −10 Pa and the pressure in the mixer 156 in the range of −2000 Pa to 2000 Pa until the end of swelling. At this time, the oxygen concentration in the dispersion chamber 132 was less than 2 vol%, so that no problem was found in terms of explosion protection. The water content in the raw material dope was 0.3% by mass.

(2) Dissolution / filtration The swelling liquid was fed from the dispersion device 13 to the heating device 26 by the pump 25. It heated to 50 degreeC with the heating apparatus 26, and also heated to 90 degreeC under the pressurization of 2 MPa, and was dissolved completely. The heating time was 15 minutes. The temperature was lowered to 36 ° C. with a temperature controller 27 and passed through a filtration device 28 having a filter medium having a nominal pore diameter of 8 μm to obtain a raw material dope having a solid content concentration of 19% by mass (hereinafter referred to as a raw material dope before concentration). At this time, the outlet pressure of the temperature controller 27 was 1.5 MPa, the primary filtration pressure was 1.0 MPa, and the secondary filtration pressure was 0.5 MPa. In addition, the filter, housing, and piping exposed to high temperature used the thing which has a jacket which distribute | circulates the heat medium for heat insulation heating using the thing made from Hastelloy alloy and excellent in corrosion resistance.

(3) Concentration, filtration, and defoaming The raw material dope before concentration is flushed in a flash device 31 adjusted to normal pressure at 36 ° C., and the evaporated solvent is liquefied by a condenser and recovered and separated by a recovery device 32. . The solid content concentration of the raw material dope after the flash was 21.8% by mass. The recovered solvent was adjusted for reuse by the regenerator 33. The temperature of the raw material dope in the flash tank was 36 ° C., and the average residence time in the tank was 50 minutes. The shear viscosity measured at 36 ° C. after collecting this raw material dope was 450 Pa · s at a shear rate of 10 (1 / s).

  Next, bubbles were removed by irradiating the raw material dope with weak ultrasonic waves. Thereafter, the liquid was fed to the filtration device 35 while being pressurized to 1.5 MPa using the pump 34. In the filter device 35, first, the sintered fiber metal filter having a nominal pore diameter of 10 μm was passed, and then, the sintered fiber filter having the same pore diameter 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 temperature of the raw material dope after filtration was adjusted to 36 ° C. and stored in a 2000 L stainless steel stock tank 30. The stock tank 30 had an anchor blade 42 on the central axis and was constantly stirred at a peripheral speed of 0.3 m / sec. When preparing the raw material dope from the pre-concentration dope, no problems such as corrosion occurred at all in the wetted parts of the dope of each apparatus.

(4) Discharge Film deposition was performed using the film deposition line 40 shown in FIG. Subsequently, the raw material dope 36 in the stock tank 30 was fed by the feedback control by the inverter motor so that the primary pressure of the high precision gear pump became 0.8 MPa with the primary pressure increasing gear pumps 46, 47, 48. The high-precision gear pumps 46 to 48 had a volume efficiency of 99.2% and a discharge rate variation rate of 0.5% or less. The discharge pressure was 1.5 MPa. As the dope liquid supply channel, three channels of an intermediate layer dope channel 43, a support surface dope channel 44, and an air surface dope channel 45 were used. The casting die 71 was equipped with a feed block 70 having a width of 1.8 m and adjusted for co-casting to form a three-layer film.

(5) Production of dope UV agent a (2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole), UV agent b (2 (2′-hydroxy-3 ′, 5 ′) -Di-tert-amylphenyl) 5-chlorobenzotriazole) and a retardation control agent (N, N′-di-m-tolyl-N ″ -p-methoxyphenyl-1,3,5-triazine-2, 4,6-triamine), 86.5 parts by mass of dichloromethane, 13 parts by mass of acetone, 0.5 parts by mass of n-butanol, and the raw material dope 36 are mixed with stock solution 51 for intermediate layer. Placed in tank 50. The intermediate layer additive solution 51 was fed to the raw material dope 36 in the intermediate layer dope channel 43 by the pump 52. And it mixed through the static mixer 53, and the dope for intermediate | middle layers was produced | generated.

  0.05 parts by mass of silicon dioxide (particle size: 15 nm, Mohs hardness: about 7) as matting agent and citric acid ester mixture (citric acid, citric acid monoethyl ester, citric acid diethyl ester, citric acid triethyl ester) as peeling accelerator ) Was dissolved or dispersed in 0.006 parts by mass, the raw material dope 36 and the mixed solvent 37 to obtain a support surface addition liquid 56. The support surface additive liquid 56 was placed in the stock tank 55 and fed to the raw material dope 36 flowing in the support surface dope channel 44 at a desired flow rate using a pump 57. And it was made to mix with the static mixer 58, and the dope for support body surfaces was produced | generated.

  An air surface additive solution 61 was prepared by dispersing in a silicon dioxide mixed solvent 37 and placed in a stock tank 60. The air surface additive solution 61 was fed to the raw material dope 36 in the air surface dope channel 45 by the pump 62. And it was made to mix through the static mixer 63 and the dope for air surfaces was produced | generated.

(6) Casting Each film thickness (air surface, intermediate layer, support surface) of the target cellulose acylate film is 4 μm, 73 μm, and 3 μm, respectively, and each dope (intermediate) Casting was carried out by adjusting the flow rate of the dope for the layer, the dope for the support surface, and the dope for the air surface. The casting was performed such that the width W2 of the casting film 80 was 1570 mm. In order to adjust the temperature of each dope to 36 ° C, a jacket (not shown) was provided on the casting die 71, and the inlet temperature of the heat transfer medium supplied into the jacket was set to 36 ° C.

  The casting die 71, the feed block 70, and the piping were all kept at 36 ° C. during film formation. The casting die 71 was a coat hanger type, and thickness adjusting bolts (heat bolts) were provided at a pitch of 20 mm, and those equipped with an automatic thickness adjusting mechanism using heat bolts were used. The heat bolt can also set a profile according to the liquid feed amount of the high-precision gear pump by a preset program, and can be set by an adjustment program based on the profile of an infrared thickness meter (not shown) installed in the film deposition line 40 The feedback control also has a possible performance. The thickness difference between two arbitrary points separated by 50 mm in the film excluding the casting edge portion of 20 mm was within 1 μm, and the maximum difference in the width direction thickness was adjusted to be 3 μm / m or less. The average thickness accuracy of each layer was controlled so that both outer layers were controlled to ± 2% or less, the mainstream was controlled to ± 1% or less, and the total thickness was adjusted to ± 1.5% or less.

  A decompression chamber 81 for decompressing was installed on the primary side of the casting die 71. The degree of decompression of the decompression chamber 81 is such that a pressure difference of 1 Pa to 5000 Pa occurs before and after the casting bead and can be adjusted according to the casting speed. Moreover, the temperature of the decompression chamber 81 was equipped with the mechanism which can be set higher than the condensation temperature of the gas around a casting part. Labyrinth packings (not shown) were provided at the front and rear of the bead. Moreover, the opening part was provided in both ends. Furthermore, in order to adjust the disturbance of both edges of the casting bead, the one to which an edge suction device (not shown) is attached was used.

The material of the casting die 71 is a double-layer stainless steel, and has a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less, and is approximately the same corrosion resistance as that of SUS316 in a forced corrosion test with an aqueous electrolyte solution. The material which has the property was used. Further, a corrosion-resistant material that does not cause pitting (opening) at the gas-liquid interface even when immersed in a mixed solution of dichloromethane, methanol, and water for 3 months was used. The finishing accuracy of the wetted surfaces of the casting die 71 and the feed block 70 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-contact part of die-tip tip, it processed so that R might be 50 micrometers or less over the slit full width. The shear rate inside the die was in the range of 1 (1 / sec) to 5000 (1 / sec). Further, a WC coating was applied to the lip end of the casting die 71 by a thermal spraying method to provide a cured film.

  Furthermore, in order to prevent the dope flowing out from the slit end of the casting die 71 from locally drying and solidifying, the mixed solvent solubilizing the dope is placed on one side of the casting bead end and the slit gas-liquid interface. It was supplied at 0.5 ml / min. The pulsation rate of the pump supplying this liquid was 5% or less. Further, the pressure on the back surface of the bead was reduced by 150 Pa by the decompression chamber 81. In order to keep the temperature of the decompression chamber 81 constant, a jacket (not shown) was attached. A heat transfer medium adjusted to 35 ° C. was supplied into the jacket. The edge suction air volume that can be adjusted in the range of 1 L / min to 100 L / min was used, and in this example, it was appropriately adjusted in the range of 30 L / min to 40 L / min.

A stainless steel endless band having a width of 2.1 m and a length of 70 m was used as the casting band 72 as a support. The casting band 72 was 1.5 mm in thickness and polished so that the surface roughness was 0.05 μm or less. The material was made of SUS316 and had sufficient corrosion resistance and strength. The thickness unevenness of the entire casting band 72 was 0.5% or less. The casting band 72 was driven by two rotating rollers 73 and 74. At this time, the tension of the casting band 72 is adjusted to 1.5 × 10 ⁴ kg / m so that the relative speed difference between the casting band 72 and the rotating rollers 73 and 74 is 0.01 m / min or less. did. The speed fluctuation of the casting band 72 was 0.5% or less. Further, both ends of the casting band 72 were detected and controlled so that the meandering in the width direction of one rotation was limited to 1.5 mm or less. Further, the positional fluctuation in the vertical direction between the die lip tip and the casting band 72 immediately below the casting die 71 was set to 200 μm or less. Three layers of dope (air surface, intermediate layer, support surface) were co-cast on the casting band 72 from the casting die 71.

As the rotating rollers 73 and 74, those capable of feeding a heat transfer medium therein were used so that the temperature of the casting band 72 could be adjusted. A heat transfer medium (water) at 5 ° C. was passed through the rotary roller 73 on the casting die 71 side, and a heat transfer medium (water) at 40 ° C. was passed through the other rotary roller 74. The surface temperature of the center part of the casting band 72 immediately before casting was 15 ° C., and the temperature difference between both ends was 6 ° C. or less. The casting band 72 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 has 2 pinholes of less than 10 μm / m2. What was ² or less was used.

The temperature of the casting chamber 76 was kept at 35 ° C. using the temperature control equipment 77. The casting film 80 formed from the dope cast on the casting band 72 was first dried by parallel-flow drying air. The overall heat transfer coefficient from the drying air to the cast film 80 during drying was 24 kcal / m ² · hr · ° C. The temperature of the drying air was 135 ° C. on the upstream side of the upper part of the casting band 72 and 140 ° C. on the downstream side. Further, the lower part of the casting band 72 was blown from the blowers 82, 83, and 84 so that the temperature was 65 ° C. The saturation temperature of each drying wind was around -8 ° C. The oxygen concentration in the dry atmosphere on the casting band 72 was kept at 5 vol%. Note that the air was replaced with nitrogen gas in order to maintain the oxygen concentration at 5 vol%. Further, in order to condense and recover the solvent in the casting chamber 76, a condenser (condenser) 78 was provided, and the outlet temperature thereof was set to -10 ° C.

(7) Stripping / Drying For 5 seconds after casting, the wind-shielding device 85 prevents the drying air from directly hitting the dope and casting film 80, and the static pressure fluctuation in the immediate vicinity of the casting die 71 is suppressed to ± 1 Pa or less. did. When the solvent ratio in the cast film 80 reached 150% by mass on the dry basis, the film was peeled off from the casting band 72 as a film 87 (hereinafter referred to as a wet film) while being supported by a peeling roller. The peeling tension at this time is 10 kgf / m, and the peeling speed (peeling roller draw) is in the range of 100.1% to 110% with respect to the speed of the casting band 72 in order to suppress the peeling failure. Adjusted appropriately. The surface temperature of the wet film 87 was 15 ° C. The drying speed on the casting band 72 was an average of 60% by mass dry weight reference solvent / min. The solvent gas generated by drying was condensed and liquefied by a condenser 78 at −10 ° C. and recovered by a recovery device 79. The recovered solvent was adjusted and then reused as a dope preparation solvent. At that time, the amount of water contained in the solvent was adjusted to 0.5% or less. The drying air from which the solvent was removed was heated again and reused as drying air. The wet film 87 was conveyed through the roller of the crossing section 90 and sent to the tenter 100. At this time, 40 ° C. dry air was blown from the blower 91 to the wet film 87. In addition, a tension of about 20 N was applied to the wet film 87 during the conveyance with the roller of the crossing section 90.

  The wet film 87 sent to the tenter 100 was transported through the drying zone of the tenter 100 while being fixed at both ends with clips, and dried with drying air. The clip was cooled by supplying a heat transfer medium at 20 ° C. The tenter was driven by a chain, and the speed fluctuation of the sprocket was 0.5% or less. Further, the tenter 100 was divided into three zones, and the drying air temperature of each zone was set to 90 ° C., 100 ° C., and 110 ° C. from the upstream side. The gas composition of the drying air was set to a saturated gas concentration of −10 ° C. The average drying speed in the tenter 100 was 120% by mass (dry weight reference solvent) / min. The conditions of the drying zone were adjusted so that the amount of residual solvent in the film was 7% by mass at the exit of the tenter 100. In the tenter 100, stretching in the width direction was also performed while transporting. When the width of the wet film 87 when transported to the tenter 100 is 100%, the widening amount is 103%. The stretching ratio (tenter driven draw) from the peeling roller 86 to the tenter 100 inlet was 102%. As for the stretching ratio in the tenter 100, the difference in the actual stretching ratio in the portion separated by 10 mm or more from the tenter biting portion was 10% or less, and the difference in the stretching ratio at any two points 20 mm apart was 5% or less. . The ratio of the length of the base end fixed with a tenter was 90%. The solvent evaporated in the tenter 100 was condensed and liquefied at a temperature of −10 ° C. and recovered. A condenser (not shown) was provided for condensation recovery, and the outlet temperature was set to -8 ° C. The water content contained in the solvent was adjusted to 0.5% by mass or less and reused. Then, the film was sent out from the tenter 100 as a film 101.

Then, the ear-cleaving device 102 cuts the ears at both ends within 30 seconds from the exit of the tenter 100. Ears 50 mm on both sides were cut with an NT-type cutter, and the cut ears were blown to a crusher 103 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 preparation together with cellulose acylate flakes as a raw material for dope preparation. The oxygen concentration in the dry atmosphere of the tenter 100 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 a drying chamber 105 described later, the film 101 was preheated in a predrying chamber (not shown) to which 100 ° C. drying air was supplied.

  The film 101 was dried at a high temperature in a drying chamber 105. The drying chamber 105 was divided into four sections, and drying air at 120 ° C., 130 ° C., 130 ° C., and 130 ° C. was supplied from the blower (not shown) from the upstream side. The conveying tension of the film 101 by the roller 104 was 100 N / width, 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 104 was 90 degrees and 180 degrees (exaggerated in FIG. 2). The roller 104 was made of aluminum or carbon steel, and a hard chrome plating was applied to the surface. The roller 104 has a flat surface shape and a matt-processed surface by blasting. All the vibrations due to the rotation of the roller 104 were 50 μm or less. The roller deflection at a tension of 100 N / width was selected to be 0.5 mm or less.

  The solvent gas contained in the drying air was adsorbed and recovered using the adsorption recovery device 106. The adsorbent was activated carbon, and desorption was performed using dry nitrogen. The recovered solvent was reused as a dope preparation solvent after adjusting the water content to 0.3% by mass or less. In addition to solvent gas, the drying air contains plasticizers, UV absorbers, and other high-boiling substances, so these were removed by a cooler and a pre-adsorber that were cooled and removed, and were recycled and used. 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 the condensation method among all the evaporation solvents was 90 mass%, and most of the remainder was collect | recovered by adsorption collection.

  The dried film 101 was conveyed to a first humidity control chamber (not shown). A drying air of 110 ° C. was supplied to the transition portion between the drying chamber 105 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 101 was conveyed to a second humidity control chamber (not shown) that suppresses the curling of the film 101. In the second humidity control chamber, air of 90 ° C. and humidity 70% was directly applied to the film 101.

  The film 101 after humidity control was cooled to 30 ° C. or lower in the cooling chamber 107 and both ends were cut off. The forced charge removal device (charge removal bar) 108 was installed so that the film voltage during conveyance was always in the range of -3 kV to +3 kV. Further, knurling was performed on both ends of the film 101 by a knurling roller 109. The knurling was applied by embossing from one side, the knurling width was 10 mm, and the pressing pressure was set so that the maximum height was 12 μm higher than the average thickness on average.

(8) Winding Then, the film 101 was conveyed to the winding chamber 110. The winding chamber 110 was kept at a room temperature of 28 ° C. and a humidity of 70%. Furthermore, an ion wind static elimination device (not shown) was also installed so that the film voltage would be -1.5 kV to +1.5 kV. The product width of the film (thickness 80 μm) 101 thus obtained was 1475 mm. The diameter of the winding roller 111 was 169 mm. The tension pattern was such that the winding start tension was 360 N / width and the winding end was 250 N / width. The total winding length was 3940 m. The period during winding was 400 m, and the oscillating width was ± 5 mm. Further, the pressing roller 112 was pressed against the winding roller 111 and the pressure was set to 50 N / width. The temperature of the film 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 (dry weight reference solvent) / min 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 film 101 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 101 was formed, no peeling residue of the casting film 80 formed from the dope was observed on the casting band 72.

(9) Results and Evaluation After the production according to Example 1 was carried out for 500 hours, vibration due to bearing wear, contamination with foreign matter, etc. did not occur, and the operating state of the dispersion apparatus was stable. Further, no contamination due to adhesion of cellulose acylate powder occurred in the dispersion chamber.

<Comparative Example 1>
As the dispersion device, a device in which a rotor with a stirring blade attached and a motor arranged outside the dispersion chamber are connected by a shaft penetrating the dispersion chamber to perform dispersion is used. A rubber seal was used between the shaft and the dispersion chamber. Perfluoro rubber (Perflo PF, Nichias Corporation) was used as the rubber material. The other conditions were the same as in Example 1. As a result, after 100 hours from the operation, liquid leakage occurred due to wear of the rubber, and production was stopped.

<Comparative example 2>
A dispersion device that does not circulate nitrogen gas was used. The other conditions were the same as in Example 1. As a result, 50 hours after the operation, a large amount of cellulose acylate powder adhered to the dispersion chamber and became an aggregate to close the dispersion chamber.

It is explanatory drawing showing the production line of dope. It is explanatory drawing showing a film forming line. It is sectional drawing of a dispersion apparatus. It is a perspective view of a 1st rotor and a 2nd rotor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dope production line 13 Dispersion apparatus 40 Film production line 132 Dispersion chamber 140 Rotor support shaft 142 Bearing 144 First rotor 146 Stirring blade 148 Second rotor 150 Drive shaft 152 Motor 154 Discharge port 156 Mixer 160 Gas circulation passage 162 Pressure control valve

Claims (7)

In a dispersion apparatus in which a polymer and a solvent are charged into a dispersion chamber provided with a stirring blade, and the stirring blade is rotated to disperse the polymer in the solvent.
A rotor disposed in the dispersion chamber and connected to the stirring blade to rotate integrally;
A dispersion apparatus comprising: a rotor drive unit disposed outside the dispersion chamber so as to face the rotor across a chamber wall of the dispersion chamber and configured to rotationally drive the rotor by a magnetic force. While alternately forming magnetic poles having different polarities along the rotation direction of the rotor on each of the facing surfaces where the rotor and the rotor driving means face each other,
The dispersion apparatus according to claim 1, wherein the rotor is rotated by shifting a position of the magnetic pole formed by the rotor driving unit in a rotation direction of the rotor.   The dispersion apparatus according to claim 1, wherein the rotor is rotatably connected to a rotation shaft standing in the dispersion chamber via a bearing made of a non-metallic material. A gas circulation passage that connects the vicinity of the discharge portion from which the dispersion produced by the dispersion is discharged and the dispersion chamber;
Pressure control means that is inserted into the gas circulation passage, changes the flow rate of the gas passing through the gas circulation passage, and controls the pressure in the vicinity of the discharge portion and the pressure in the dispersion chamber. The dispersion apparatus according to claim 1.   The dispersion apparatus according to claim 4, wherein the pressure in the dispersion chamber is maintained in a range of −5000 Pa to −10 Pa.   The dispersion apparatus according to claim 4 or 5, wherein the pressure in the vicinity of the discharge unit is maintained in a range of -2000 Pa to 2000 Pa. 7. The mixer according to claim 4, wherein a mixer for further mixing the dispersion liquid is provided in the vicinity of the discharge portion, and the mixer and the dispersion chamber are connected by the gas circulation passage. Distributed device.

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