JP2006117904A - Method and apparatus for producing dope and method for forming film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently stir and mix a raw material dope with an additive. <P>SOLUTION: An addition nozzle 160 is formed so as to extend to the tip in the diametrical direction of a pipeline 150 for the dope. A slit-like addition port 162 is formed at the tip of the addition nozzle 160 and an additive 51 for an interlayer is added from a gap of the slit of the addition port 162. The addition nozzle 160 is arranged so that the longitudinal direction of the addition port 162 intersects the lateral end 152a of an element 152 closest to the addition nozzle 160 at right angles. The additive is surely divided from the top of a static mixer by adding the additive from the slit-like addition port 162. Since the additive is stably injected without rotation, the raw material dope can efficiently be stirred and mixed with the additive. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for manufacturing a dope, and more particularly to a method and an apparatus for manufacturing a dope for forming a polymer film used for optical applications such as a liquid crystal display device. Furthermore, this invention relates to the film forming method using the dope manufactured with the manufacturing method and apparatus of the said dope.

  Various polymers are used as polymers for optical polymer films. Among them, cellulose acylate films are widely used because they have transparency and moderate moisture permeability, have high mechanical strength, and low dimensional stability in humidity and temperature. One.

  A liquid crystal display device includes a polarizing plate and an optical compensation film, and the polarizing plate often has a structure having protective films on both sides of a polarizing film. In recent years, the optical compensation film may be replaced with one of the protective films. It is known that a cellulose acylate film serves as both a protective film and an optical compensation film by giving excessive optical properties.

On the other hand, the demand for liquid crystal display devices is increasing as a liquid crystal television display device, and there is a demand for higher brightness, larger screen, and higher image quality. In these high quality improvements, minute mixing unevenness of the additive relating to the present invention has become obvious and has become a problem.

  In the case of forming a cellulose acylate film, a solution film forming method is often applied. The solution casting method involves mixing a polymer with a solvent to form a raw material dope, and adding various additives such as a plasticizer, an ultraviolet absorber, a matting agent, and a retardation control agent to the raw material dope. In this method, the dope is produced by casting the dope from the die to the casting support, and the casting film is peeled off at a position having self-supporting property and dried in the drying step. The casting support is a drum or band that continuously rotates.

  In the production of the dope, the additive is added to the raw material dope immediately before the die and stirred by a static mixer. A static mixer puts a substance in a cylindrical container, divides the flow of the substance into a plurality of parts in the container, rotates the directions of the divided flows in the container, and repeats the division and rotation. Is mixed.

  A typical static mixer is a static mixer TM (manufactured by Kenix). In the static mixer, a rectangular plate is formed by twisting, a clockwise element that divides the substance flow into two parts and rotates it 180 ° clockwise, and a substance flow that divides the substance flow into two parts and rotates counterclockwise 180. The counterclockwise elements to be rotated are arranged so as to be alternately shifted by 90 ° in the container. When the mixture to be doped is put into such a static mixer, the mixture is continuously stirred.

If the stirring is insufficient and the dope is not homogeneous, the quality of the product will deteriorate. For this reason, various devices have been made so that stirring can be performed reliably. For example, Japanese Patent Application No. 2003-282937 discloses a technique in which the heating condition of the static mixer and the dope pressure are controlled to prevent the generation of the temperature distribution of the dope and obtain a homogeneous dope. Has been proposed. Patent Document 1 below describes an example in which the additive addition port is brought close to a static mixer.
JP 2003-53752 A

  However, it has been difficult to say that the conventional method can efficiently perform stirring. That is, conventionally, since the additive is added from a circular addition nozzle arranged at the substantially central part of the pipe through which the raw material dope flows, the inner peripheral wall of the pipe from the center of the pipe through which the raw material dope flows It takes time to spread in the direction of. For this reason, in order to perform sufficient stirring, it is necessary to use a mixer having a large number of elements, and there is a problem that the process is increased in size and cost.

  An object of this invention is to provide the manufacturing method of dope which can perform stirring efficiently.

  In order to achieve the above object, the present invention adds a additive to a raw material dope in which a polymer is dissolved in a solvent, and stirs and mixes the mixture with an in-line mixer to produce a dope. An additive is added from a slit-like addition port extending in the direction.

In addition, the present invention preferably satisfies the following.
(1) The length of the slit of the addition port is 20% to 80% of the inner diameter of the pipe.
(2) The slit gap of the addition port is 0.1 mm to 1/10 of the inner diameter of the pipe.
(3) The distance from the tip of the addition port to the in-line mixer is 1 mm to 250 mm.
(4) When the flow rate of the additive is V1 and the flow rate of the raw material dope is V2, 1 ≦ V1 / V2 ≦ 5.
(5) The raw material dope has a viscosity at 20 ° C. of 5000 cp to 500000 cp, and 0.1 (1 / s) ≦ V3 ≦ 30 (1 / s) when the shear rate in the pipe is V3. And the number of lay nozzles is 200 or less, and the additive has a viscosity at 20 ° C. of 0.1 cp to 100 cp.
(6) The addition ratio of the additive is 0.1% to 50% in flow rate ratio.
(7) The in-line mixer is a static mixer, and the addition nozzle is arranged so that the longitudinal direction of the addition port and the upstream end of the element are substantially perpendicular.

  The film-forming method of the present invention is characterized in that a dope produced by the above-described dope producing method is used, and this dope is cast to form a cast film. You may comprise the support body for photography used when manufacturing the film for polarizing plate protective films, and the photographic film with the said film forming method. Furthermore, it can be used as an optical compensation film for improving the viewing angle dependency of a liquid crystal display device for television. In particular, it is effective for applications that also serve as a protective film for a polarizing film. Therefore, it is used not only in the conventional TN mode but also in the IPS mode, OCB mode, VA mode, and the like. Moreover, you may comprise a polarizing plate using the said film for polarizing plate protective films.

  According to the present invention, since the additive is added from the slit-shaped addition port extending in the diameter direction of the pipe through which the raw material dope flows, the additive and the raw material dope can be efficiently stirred and mixed in the in-line mixer. For this reason, the number of elements of the in-line mixer can be reduced, and the process can be reduced in size and cost.

  In addition, since the present invention can obtain a homogeneous dope by efficiently stirring and mixing the additive and the raw material dope, a film forming method using the dope, a polarizing plate protecting film, an optical compensation film, a photograph By applying to a support for a high-quality, a high-quality product can be obtained.

[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). Hereinafter referred to as TAC.
(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 to use particles having 90% by mass or more of TAC of 0.1 mm to 4 mm.

  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 acetyl groups, and DSB is the total substitution degree with hydroxyl groups other than the acetyl groups 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 substituent at the 6-position hydroxyl group, more preferably 25% or more is a substituent at the 6-position hydroxyl group, more preferably 30% or more, and particularly 33% or more is 6%. A substituent of a hydroxyl group is preferred. Furthermore, it is preferable that the substitution value at the 6-position of the cellulose acylate is 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. is there. With these cellulose acylates, a solution having a preferable solubility (dope) can be produced. In particular, in a non-chlorine organic solvent, a good solution can be produced. Furthermore, a solution having a low viscosity and good filterability can be produced.

  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 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, 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 is preferably used, and dichloromethane is most preferably used. From the viewpoint of physical properties such as solubility of TAC, peelability of cast film from the support, mechanical strength of the film, and optical properties of the film, in addition to dichloromethane, one or more alcohols having 1 to 5 carbon atoms are used. It is preferable to mix several types. 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. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, but methanol, ethanol, n-butanol or a mixture thereof is 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 paragraphs [0140] to [0195] of Japanese Patent Application No. 2004-264464. These descriptions are also applicable to the present invention. The same applies to additives such as solvents and plasticizers, deterioration inhibitors, UV absorbers (UV agents), optical anisotropy control agents, retardation control agents, dyes, matting agents, release agents, release accelerators, etc. The details are described in paragraphs [0196] to [0516] of Japanese Patent Application No. 2004-264464.

[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 dissolution tank 13. Next, the TAC contained in the hopper 14 is fed into the dissolution tank 13 while being measured. The additive solution is sent from the additive tank 15 to the dissolution tank 13 by opening and closing the valve 16. In addition to the method of sending the additive as a solution, for example, when the additive is liquid at room temperature, it is also possible to send the additive to the dissolution tank 13 in the liquid state. In addition, when the additive is solid, it can be fed into the dissolution tank 13 using a hopper. 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 15. 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 13 through independent pipes.

  In the above description, the order of putting into the dissolution tank 13 is the solvent (used in the meaning including the case of the mixed solvent), TAC, and additive, but it is not limited to this order. It is also possible to send a preferable amount of the solvent after sending the TAC to the dissolution tank 13 while measuring it. Further, the additive does not necessarily need to be put in the dissolution tank 13 in advance, and can be mixed in a mixture of TAC and a solvent in a later step.

  A jacket 17 is provided so as to enclose the dissolution tank 13. A first stirring blade 19 that is rotated by a motor 18 is attached. Furthermore, it is preferable that the 2nd stirring blade rotated by the motor 20 is attached. The first stirring blade is preferably an anchor blade, and the second stirring blade 21 is preferably a dissolver type eccentric stirring machine. It is preferable to flow the heat transfer medium through the jacket 17 and adjust the temperature in the dissolution tank 13 in the range of −10 ° C. to 55 ° C. By appropriately selecting and rotating the first stirring blade 19 and the second stirring blade 21, the swelling liquid 22 in which the TAC is swollen in the solvent can be obtained.

  The swelling liquid 22 is sent to the heating device 26 by the pump 25. The heating device 26 preferably uses a jacketed pipe, and preferably has a configuration capable of pressurizing the swelling liquid 22. A raw material dope is obtained by dissolving TAC or the like in a solvent under heating or pressure heating conditions of the swelling liquid 22. In this case, the temperature of the swelling liquid 22 is preferably 0 ° C to 97 ° C. Moreover, the cooling dissolution method which cools the swelling liquid 22 to the temperature of -150 degreeC--10 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 temperature of the raw material dope is set to about room temperature by the temperature controller 27, filtration by the filtering device 28 is performed 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. 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 solution film-forming dope described later. However, the method of dissolving TAC after preparing the swelling liquid 22 takes time as the concentration of TAC is increased, and may cause a problem in terms of cost. In that case, it is preferable to carry out a concentration step of preparing a raw material dope having a target concentration after preparing a raw material dope having a concentration lower than the target TAC concentration. The raw material dope filtered by the filtering device 28 is sent to the flash device 31 through the valve 29. A part of the solvent in the raw material dope 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. Furthermore, it is preferable to remove bubbles in the raw material dope. Defoaming may be performed by any known method, for example, an ultrasonic irradiation method. Thereafter, the liquid is fed to the filtration device 35 to remove foreign matters. At this time, the temperature of the raw material dope is preferably 0 ° C. to 200 ° C. Thus, the raw material dope 36 having a TAC concentration of 5% by mass to 40% by mass can be manufactured. The produced raw material dope 36 is stored in the stock tank 30.

  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, a raw material, the dissolution method and addition method of an additive, the filtration method, dope manufacturing methods, such as defoaming [0616] The paragraph is detailed. These descriptions are also applicable 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) 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 additives such as an ultraviolet absorber and 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 the static mixer 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, 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 the static mixer 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, silicon dioxide) that suppresses adhesion between film surfaces when the film is wound into a roll. The air surface additive 61 may contain additives such as a peeling accelerator, a plasticizer, and an ultraviolet absorber.

  As will be described in detail later, in the dope manufacturing process, the present invention is an addition nozzle 160 for adding an additive to each raw material dope of the intermediate layer raw material dope, the support surface raw material dope, and the air surface raw material dope (FIG. 4). The material dope and the additive can be obtained by devising the shape of the shape shown in FIG. 5, the distance between the addition nozzle 160 and the static mixers 53, 58 and 63, the flow rate ratio of the material dope and the additive, and the like. Efficient stirring and mixing are possible.

  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.

"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 3.5 mm by 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 ceramics that can be ground, have low porosity, are not brittle, have good corrosion resistance, and have no adhesion to the casting die 71. 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 its both edges are gripped by a clip and conveyed. Moreover, it is preferable to divide the inside of the tenter 100 into different temperature zones to adjust the drying conditions. It is also possible to stretch the wet film 87 in the width direction using the tenter 100. As described above, 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.

  In the polymer film of the present invention, it is preferable that the axial shift between the slow axis of an arbitrary region of the film and the slow axis of all the regions adjacent to the arbitrary region is less than 2.0 degrees. In addition, it is more preferable that the axial deviation is less than 1.0 degree. Moreover, it is a polymer film manufactured by the solution casting method, and it is preferable to relax in the width direction of the film after stretching in the width direction of the film when performing the solution casting method.

  The stretching and the relaxation are performed by gripping the film with gripping means. 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. When the film width is L2 (mm) and the film width is L3 (mm) when the film is relaxed and the gripping means releases the film, 1 <(L2-L3) / L1 × 100 <15 Preferably there is. When performing the stretching relaxation, it is preferable that the drying temperature of the film is kept substantially the same. 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 present invention also includes a polymer film produced by a melt film forming method.

  It is preferable that the region is a region of 50 mm in each direction in the longitudinal direction and the width direction of the film. 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 solution casting method of the present invention is a solution casting in which a dope containing a polymer and a solvent is cast on a support and then peeled off from the support as a film, and stretching is relaxed while both ends of the film are held by gripping means. In the method, it is preferable that the film is stretched in the width direction during the stretching relaxation and then relaxed. When stretching the film, the width of the film when gripping both ends of the film is L1 (mm), the width of the film when the film is fully stretched in the width direction is L2 (mm), and the film is relaxed Thus, it is more preferable that the relationship 1 <(L2−L3) / L1 × 100 <15 is satisfied when the width of the film when the gripping means separates the film is L3 (mm).

  When film stretching is relaxed, it is preferable to keep the film drying temperature substantially the same. More preferably, the drying temperature of the film is substantially the same 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 said casting process to the process of winding up the said film.

  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, a preliminary drying chamber (not shown) is provided between the ear opener 102 and the drying chamber 105, and the preliminary drying of the film 101 can suppress the change in the shape of the film due to a sudden rise in the film temperature. preferable.

  The film 101 is conveyed to the cooling chamber 107 and cooled to approximately room temperature. Note that 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. The thickness of the film can also be applied when manufacturing a thin film having a thickness of 15 μm to 100 μm.

  In the solution casting method of the present invention, when casting dopes, two or more kinds of dopes are simultaneously laminated or sequentially laminated. Furthermore, you may combine both casting. When performing simultaneous lamination and co-casting, a casting die 71 to which a feed block 70 is attached may be used as shown in FIG. 2, or a multi-manifold 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.

  As shown in FIG. 2, the desired characteristics of the film 101 can be easily obtained by co-casting three kinds of dopes. 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.

  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 paragraphs [0617] to [0889] of Japanese Patent Application No. 2004-264464. 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 paragraphs [0112] to [0139] of Japanese Patent Application No. 2004-264464. 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 surface treatment functional layer imparting method for realizing various functions and properties on the cellulose acylate film is described in Japanese Patent Application No. 2004-264464, paragraphs [0890] to [1087]. It is included. These are also applicable to the present invention.

The functional layers preferably contain at least one surfactant 0.1mg / m ² ~1000mg / m ² containing. Further, the functional layers preferably contain at least one sort of plasticizers in the 0.1mg / m ² ~1000mg / m ² containing. 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 a surface-treated functional layer for realizing various functions and properties of cellulose acylate film includes detailed conditions and methods described in [0843] to [1079] of Japanese Patent Application No. 2003-319673. Is also included. These are also applicable to the present invention.

(Use)
The cellulose acylate film is particularly useful as a polarizing plate protective film. Usually, two polarizing plates each having a cellulose acylate film bonded to a polarizer are bonded to a liquid crystal layer to produce a liquid crystal display device. However, the arrangement of the liquid crystal layer and the polarizing plate is not limited, and various known arrangements can be employed. Japanese Patent Application No. 2004-264464 describes in detail TN type, STN type, VA type, OCB type, reflection type, and other examples of liquid crystal display devices. This method can also be applied to the present invention. 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 use as an optical compensation film is also described as a biaxial cellulose acylate film imparting appropriate optical performance. This can also be used as a polarizing plate protective film. These descriptions are also applicable to the present invention. Details are described in paragraphs [1088] to [1265] of Japanese Patent Application No. 2004-264464.

  Moreover, the cellulose triacetate film (TAC film) which is excellent in an optical characteristic by the manufacturing method of this invention can be obtained. The TAC film can be used as a polarizing plate protective film or a base film for a photographic photosensitive material. Further, it can be used as an optical compensation film for improving the viewing angle dependency of a liquid crystal display device such as a television. In particular, it is effective for applications that also serve as a protective film for a polarizing plate. Therefore, it is used not only for the conventional TN mode but also for the IPS mode, OCB mode, VA mode, and the like. Moreover, you may comprise a polarizing plate using the said film for polarizing plate protective films.

  Hereinafter, the dope manufacturing process according to the present invention will be described in detail. In the present embodiment, the intermediate layer dope channel 43, the support surface dope channel 44, and the air surface dope channel 45 in the dope manufacturing process are the same, although the types of additives to be added are different. The configuration was as follows. For this reason, in the following description, the dope flow path 43 for the intermediate layer will be described as an example on behalf of the respective dope flow paths 43, 44, 45.

  As shown in FIG. 3, in the intermediate layer dope channel 43, elements 152 and 154 constituting the static mixer 53 are alternately arranged in a dope pipe 150 through which the intermediate layer raw material dope flows. The elements 152 and 154 are formed by twisting a rectangular plate by 180 °, and the twisting directions of the element 152 and the element 154 are reversed. The elements 152 and 154 are arranged in the longitudinal direction of the dope pipe 150 in a state shifted by 90 ° so that the side ends of the plates are orthogonal.

  On the upstream side of the static mixer 53, an additive pipe 156 through which the intermediate layer additive 51 flows is disposed. The additive pipe 156 has an addition nozzle 160 attached to the tip of a circular pipe 158 that penetrates the dope pipe 150. Then, the intermediate layer additive 51 is fed from the stock tank 50 by the pump 52 and added into the dope pipe 150 from the addition nozzle 160.

  As shown in FIGS. 4 and 5, the addition nozzle 160 is formed so as to extend in the diameter direction of the dope pipe 150 over the tip. A slit-shaped addition port 162 is formed at the tip, and the intermediate layer additive 51 is added through a gap between the slits of the addition port 162. The longitudinal direction of the addition nozzle 160 and the addition port 162 and the side end portion 152a of the element 152 closest to the addition nozzle 160 are arranged so as to be orthogonal to each other. By adding the additive from such an addition port 162, the additive is reliably divided from the top of the static mixer, and the additive is stably injected without rotation. Can be efficiently stirred and mixed.

  In order to mix the additive and the raw material dope more efficiently, the length L of the slit of the addition port 162 is preferably 20% to 98% of the inner diameter W of the dope pipe 160. If the length L of the slit of the addition port 162 is too short, the efficiency is lowered during stirring and mixing, and conversely if too long, the additive may be added to the gap between the dope pipe 150 and the element 152. .

  Further, the gap C between the slits of the addition port 162 is preferably 0.1 mm to 1/10 of the inner diameter W of the dope pipe 150. Furthermore, the distance D between the addition port 162 and the side end 152a of the element 152 is preferably 1 mm to 250 mm, and more preferably the distance D is 2 mm to 250 mm. If the distance D is too close, the addition nozzle 160 may be clogged due to the resistance of the raw material dope, and conversely, if it is too far, the additive may not be added to the center of the static mixer 53.

  Furthermore, it is preferable that 1 ≦ V1 / V2 ≦ 5 is satisfied when the flow rate of the additive is V1 and the flow rate of the raw material dope is V2. If the value of V1 / V2 is too small, the liquid may run out in the liquid feeding direction. Conversely, if the value is too large, the additive has energy and may pass through the static mixer 53 vigorously.

  Further, when the viscosity of the additive is N1 and the viscosity of the raw material dope is N2, at 20 ° C., N1 is 0.1 cp to 100 cp, N2 is 5000 cp to 500000 cp, and the viscosity ratio is 1000 ≦ N 2 / It is preferable that N1 ≦ 1000000.

  Furthermore, it is preferable that the shear rate V3 of the raw material dope flowing through the dope pipe 160 is 0.1 (1 / s) to 30 (1 / s). If the shear rate V3 is too small, the mixing may not proceed. Conversely, if the shear rate V3 is too large, the pressure loss in the dope pipe 160 will increase, and it may not be able to withstand the pressure of 20 kg. For the same reason, the raw material dope lay nozzle number Re is preferably Re ≦ 200.

  Moreover, it is preferable that the addition ratio of an additive is 0.1%-50% by flow rate ratio. If the addition ratio of the additive is too low, it is difficult to add it with high accuracy. Conversely, if it is too high, it is difficult to mix with the raw material dope.

  As described above, according to the present invention, since the additive is added from the slit-shaped addition port extending in the diameter direction of the pipe through which the raw material dope flows, the additive and the raw material dope are efficiently mixed in the static mixer. Can be stirred and mixed. For this reason, the number of elements of the static mixer can be reduced, and the process can be reduced in size and cost. In addition, since the present invention can obtain a homogeneous dope by efficiently stirring and mixing the additive and the raw material dope, a film forming method using the dope, a film for protecting a polarizing plate, a polarizing plate, and a photo By applying to a support, a high quality product can be obtained.

  In the above embodiment, an example in which a static mixer including an element formed by twisting a rectangular plate is used as an inline mixer has been described. However, the present invention is not limited to this, and other types are used. An in-line mixer may be used. As an in-line mixer, for example, it is conceivable to use a slewer mixer including elements formed by combining a plurality of strip-shaped plates in a lattice shape.

[Example]
Hereinafter, specific examples of the present invention will be described in comparison with comparative examples. The present invention is not limited to the following examples.

The used mass part is shown below.
[composition]
Cellulose triacetate (substitution degree 2.84, viscosity average polymerization degree 306, water content 0.2 mass%, viscosity 6 mass% in dichloromethane solution 315 mPa · s, average particle diameter 1.5 mm with standard deviation 0.5 mm Some powders) 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 plasticizer A (triphenyl phosphate) 7.6 parts by mass Plasticizer B (diphenyl phosphate) 3.8 parts by mass

[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. The cellulose triacetate powder (flakes) is gradually added from the hopper 14 to the 4000 L stainless steel dissolution tank 13 having the stirring blades 19 and 21 while mixing and dispersing the plurality of solvents as a mixed solvent. Was adjusted to 2000 kg. In addition, all the solvents used that the water content is 0.5 mass% or less. A dissolver type eccentric stirring shaft 21 that stirs in the dissolution tank 13 at a peripheral speed of 5 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² ) at the beginning, and an anchor blade 19 on the central shaft. And dispersed for 30 minutes under the condition of stirring at a peripheral speed of 1 m / sec (shear stress 1 × 10 ⁴ kgf / m / sec ² ). The starting temperature of dispersion was 25 ° C., and the final temperature reached 48 ° C. After completion of the dispersion, the high-speed stirring was stopped, the peripheral speed of the anchor blade 19 was set to 0.5 m / sec, and the mixture was further stirred for 100 minutes to swell the cellulose triacetate flakes to obtain a swelling liquid 22. Until the end of swelling, the inside of the tank was pressurized to 0.12 MPa with nitrogen gas. At this time, the oxygen concentration in the tank was less than 2 vol%, and the state of no problem was maintained in terms of explosion protection. The water content in the raw material dope was 0.3% by mass.

(2) Dissolution / filtration The swelling liquid 22 was fed from the dissolution tank 13 to the jacketed pipe 26 by the pump 25. It heated to 50 degreeC with the piping 26 with a jacket, 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 primary pressure of filtration was 1.5 MPa, and the secondary pressure was 1.2 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 80 ° C. and normal pressure, 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 flash tank of the flash device 31 has an anchor blade on the center axis, and deaeration was performed by stirring at a peripheral speed of 0.5 m / sec. The temperature of the raw material dope in the flash tank was 25 ° C., and the average residence time in the tank was 50 minutes. The shear viscosity of this raw material dope collected and measured at 25 ° C. 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. Moreover, the mixed solvent 37 of 86.5 mass parts of dichloromethane, 13 mass parts of acetone, and 0.5 mass part of n-butanol was produced.

(4) Discharge Film was formed using the fail film forming 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.

  The casting die 71 is equipped with a feed block 70 having a width of 1.8 m and adjusted for co-casting, and is capable of forming a three-layer film by laminating on both sides in addition to the mainstream. Was used. In the following description, a layer formed from the mainstream is referred to as an intermediate layer, a support surface side layer is referred to as a support surface, and an opposite surface is referred to as an air surface. In addition, the dope liquid supply flow path used three flow paths: an intermediate layer dope flow path 43, a support surface dope flow path 44, and an air surface dope flow path 45.

(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), mixed solvent 37 and raw material dope 36 were mixed, and intermediate layer additive solution 51 was placed in stock 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 And the casting width is 1700 mm so that the film thickness (air surface, intermediate layer, support surface) of the target TAC film is 4 μm, 73 μm and 3 μm, respectively, and the product thickness is 80 μm. Casting was performed by adjusting the flow rate of each dope (interlayer dope, support surface dope, air surface dope). 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. The casting band 72 is installed in a casting chamber 76 having wind pressure fluctuation suppressing means (not shown). 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 TAC flakes as a dope preparation raw material. 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) Comparative Evaluation In the process of manufacturing the film 101 as described above, in the dope manufacturing process shown in (5), the addition nozzle 160 having the slit-shaped addition port 162 (see FIGS. 4 and 5). ) Was used as an example. On the other hand, in the manufacturing process of the dope shown in (5), an additive was added using a conventionally used circular addition nozzle as a comparative example.

As shown in FIG. 6, after visualizing the dope manufactured by changing various conditions, the mixed state of the additive and the raw material dope was visually observed and evaluated. In both Examples and Comparative Examples, the inner diameter W of the dope pipe 150 through which the raw material dope flows was 0.055 m, the raw material dope solution density was 1300 kg / m ^3, and the atmospheric temperature of the process was 20 ° C. Crystal violet was used as a coloring agent for visualization.

[Comparative Example 1]
The speed ratio V1 / V2 between the flow rate V1 of the additive and the flow rate V2 of the raw material dope was set to 3. The viscosity N2 of the raw material dope was 20000 cp, and the viscosity N1 of the additive was 0.5 cp. The additive addition ratio was 20% in flow rate ratio. The shear rate V3 of the raw material dope was 1.3 (1 / s), and the number of lay nozzles of the raw material dope was 5. The distance D between the addition port and the static mixer was 10 mm. The number of elements of the static mixer was 42. The dope produced under such conditions was poorly mixed and color unevenness could be confirmed, so the evaluation was x.

[Comparative Examples 2 and 3]
In Comparative Examples 2 and 3, the number of elements of the static mixer was changed compared to Comparative Example 1. In Comparative Example 2, the number of elements of the static mixer was 120, and in Comparative Example 3, the number of elements of the static mixer was 132. Other conditions were the same as those in Comparative Example 1. As a result, the dope produced under the conditions of Comparative Example 2 was poorly mixed, and color unevenness could be confirmed. The dope manufactured under the conditions of Comparative Example 3 had a relatively good mixed state and no color unevenness could be confirmed.

[Example 1]
The speed ratio V1 / V2 between the flow rate V1 of the additive and the flow rate V2 of the raw material dope was set to 3. The viscosity N2 of the raw material dope was 20000 cp, and the viscosity N1 of the additive was 0.5 cp. The additive addition ratio was 20% in flow rate ratio. The shear rate V3 of the raw material dope was 1.3 (1 / s), and the number of lay nozzles of the raw material dope was 5. The distance D between the addition port and the static mixer was 10 mm. The number of elements of the static mixer was 42. Since the dope produced under such conditions was in a good mixed state and color unevenness could not be confirmed, the evaluation was ◎.

[Examples 2 to 5]
In Examples 2 to 5, the speed ratio V1 / V2 was changed with respect to Example 1. In Example 2, the speed ratio V1 / V2 is set to 0.9, in Example 3, the speed ratio V1 / V2 is set to 1, in Example 4, the speed ratio V1 / V2 is set to 5, and in Example 5, The speed ratio V1 / V2 was set to 5.5. Other conditions were the same as in Example 1. As a result, the dope produced under the conditions of Example 2 had a relatively good mixed state and no noticeable color unevenness. Since the dope produced under the conditions of Examples 3 and 4 was in a good mixed state and color unevenness could not be confirmed, the evaluation was ◎. The dope produced under the conditions of Example 5 was not very well mixed and had some color unevenness, so the evaluation was Δ.

[Examples 6 to 8]
In Examples 6 to 8, the speed ratio V1 / V2 was changed to 2.5 with respect to Example 1. Further, the viscosity N2 of the raw material dope was changed with respect to Example 1. In Example 6, the raw material dope viscosity N2 was 5000 cp, in Example 7, the raw material dope viscosity N2 was 500,000 cp, and in Example 8, the raw material dope viscosity N2 was 600000. Other conditions were the same as in Example 1. As a result, the dope produced under the conditions of Examples 6 and 7 was in a good mixed state and no color unevenness could be confirmed. The dope produced under the conditions of Example 8 was not very well mixed and had some color unevenness, so the evaluation was Δ.

[Examples 9 to 12]
In Examples 9 to 12, the speed ratio V1 / V2 was changed to 2.5, and the viscosity N2 of the raw material dope was changed to 100000 with respect to Example 1. Moreover, in Examples 9-12, the viscosity N1 of the additive was changed with respect to Example 1. In Example 9, the viscosity N1 of the additive was 0.05 cp, in Example 10, the viscosity N1 of the additive was 0.1 cp, and in Example 11, the viscosity N1 of the additive was 100 cp. In No. 12, the viscosity N1 of the additive was 150 cp. Other conditions were the same as in Example 1. As a result, the dope manufactured under the conditions of Examples 9 and 12 was not very good in the mixed state, and some color unevenness was generated. Since the dope manufactured under the conditions of Examples 10 and 11 was in a good mixed state and color unevenness could not be confirmed, the evaluation was ◎.

[Examples 13 to 15]
In Examples 13 to 15, the speed ratio V1 / V2 was changed to 2.5 with respect to Example 1, the raw material dope viscosity N2 was changed to 100,000, and the additive viscosity N1 was set to 1. Moreover, in Examples 13-15, the addition ratio of the additive was changed with respect to Example 1. In Example 13, the addition ratio was set to 0.1% in flow rate ratio, in Example 14, the addition ratio was set to 50% in flow rate ratio, and in Example 15, the addition ratio was set to 55% in flow rate ratio. As a result, the dope produced under the conditions of Examples 13 and 14 had a good mixed state and no color unevenness could be confirmed. The dope produced under the conditions of Example 15 was relatively good in the mixed state and the color unevenness was not noticeable.

[Examples 16 to 18]
In Examples 16 to 18, with respect to Example 1, the speed ratio V1 / V2 was changed to 2.5, the viscosity N2 of the raw material dope was changed to 100000, and the viscosity N1 of the additive was set to 1. Further, in Examples 16 to 18, the material dope shear rate V3 and the material dope lay nozzle number Re were changed with respect to Example 1. In Example 16, the shear rate V3 is 0.1 (1 / s) and the number of ray nozzles Re is 0.7. In Example 17, the shear rate V3 is 30 (1 / s) and the number of ray nozzles Re is 205. In Example 18, the shear rate V3 was 40 (1 / s), and the number of lay nozzles Re was 254. As a result, the dope produced under the conditions of Example 16 had a good mixed state and no color unevenness could be confirmed. When the dope was manufactured under the conditions of Example 17, the mixed state was good, but the pressure loss was slightly higher, so the evaluation was “good”. When the dope was manufactured under the conditions of Example 18, the mixed state was good, but the pressure loss was high, so the evaluation was Δ.

[Examples 19 to 22]
In Examples 19 to 22, the speed ratio V1 / V2 is changed to 2.5, the viscosity N2 of the raw material dope is changed to 100000, the viscosity N1 of the additive is 1, and the raw material dope The shear rate V3 and the number of lay nozzles Re were changed so that V3 was 5 (1 / s) and Re was 32. Moreover, in Examples 19-22, the distance D of an addition port and a static mixer was changed with respect to Example 1. FIG. In Example 19, the distance D was 1 mm, in Example 20, the distance D was 2 mm, in Example 21, the distance D was 250 mm, and in Example 22, the distance D was 275 mm. As a result, when the dope was manufactured under the conditions of Example 19, the addition nozzle was sometimes clogged. Since the dope produced under the conditions of Examples 20 and 21 was in a good mixed state and color unevenness could not be confirmed, the evaluation was ◎. When the dope was produced under the conditions of Example 22, the additive was not sometimes added to the center of the static mixer, and the mixing state varied, so the evaluation was Δ.

[Examples 23 to 25]
In Examples 23 to 25, the distance D between the addition port and the static mixer was changed to 150 mm with respect to Examples 19 to 22. Moreover, in Examples 23-25, the number of elements of the static mixer was changed with respect to Examples 19-22. Other conditions were the same as in Examples 19-22. In Example 23, the number of elements was 18, in Example 24, the number of elements was 24, and in Example 25, the number of elements was 120. As a result, the dope produced under the conditions of Example 23 was not very well mixed, and some color unevenness occurred, so the evaluation was Δ. Since the dope produced under the conditions of Examples 24 and 25 was in a good mixed state and color unevenness could not be confirmed, the evaluation was ◎.

(10) General Review As described above, it was confirmed that the raw material dope and the additive can be efficiently stirred and mixed by adding the additive from the slit-shaped addition port extending in the diameter direction of the pipe through which the raw material dope flows. . Furthermore, it can be confirmed that the raw material dope and the additive can be stirred and mixed more efficiently by devising various conditions such as the distance between the additive nozzle and the static mixer and the flow rate ratio between the raw material dope and the additive. It was.

  In addition, as a method for efficiently stirring and mixing the raw material dope and the additive, it may be considered that the raw material dope is handled in a turbulent flow region having a Ray nozzle number Re of 2000 or more, but in this way, the pressure loss becomes very large. End up. However, by applying the present invention, it was confirmed that even when the raw material dope was handled in a laminar flow region having a Ray nozzle number Re of 100 or less, mixing and stirring could be performed efficiently.

It is explanatory drawing showing the production line of dope. It is explanatory drawing showing a film forming line. It is a top view of the dope flow path for intermediate | middle layers. It is a perspective view of the dope flow path for intermediate | middle layers. It is a top view of the dope flow path for intermediate | middle layers. It is a chart showing the result of having investigated the dope mixing degree manufactured by changing the shape of nozzles and various conditions.

Explanation of symbols

36 Raw material dope 51 Intermediate layer additive 56 Support surface additive 61 Air surface additive 43 Intermediate layer dope channel 44 Support surface dope channel 45 Air surface dope channel 53, 58, 63 Static mixer 150 Dope piping 152, 154 Element 156 Additive piping 160 Addition nozzle 162 Addition port

Claims (10)

In the method for producing a dope, an additive is added to a raw material dope in which a polymer is dissolved in a solvent, and the dope is produced by stirring and mixing with an in-line mixer.
A method for producing a dope comprising a slit-like addition port extending in a diameter direction of a pipe through which the raw material dope flows, and adding the additive from the addition port.   The dope manufacturing method according to claim 1, wherein a length of the slit of the addition port is 20% to 80% of an inner diameter of the pipe.   The dope manufacturing method according to claim 1 or 2, wherein a gap between the slits of the addition port is 0.1 mm to 1/10 of the inner diameter of the pipe.   The distance from the said addition port to the said in-line mixer is 1 mm-250 mm, The manufacturing method of the dope in any one of Claims 1-3 characterized by the above-mentioned.   The dope manufacturing method according to claim 1, wherein 1 ≦ V1 / V2 ≦ 5 is satisfied, where V1 is a flow rate of the additive and V2 is a flow rate of the raw material dope. The raw material dope has a viscosity of 5000 cp to 500000 cp at 20 ° C., and 0.1 (1 / s) ≦ V3 ≦ 30 (1 / s) when the shear rate in the pipe is V3, And the number of lay nozzles is 200 or less,
The method for producing a dope according to any one of claims 1 to 5, wherein the additive has a viscosity at 20 ° C of 0.1 cp to 100 cp.   The method for producing a dope according to any one of claims 1 to 6, wherein an addition ratio of the additive is 0.1% to 50% in flow rate ratio.   A dope produced by the method for producing a dope according to claim 1, and casting the dope to form a cast film. In the dope manufacturing apparatus for adding the additive to the raw material dope in which the polymer is dissolved in the solvent, and stirring and mixing with the in-line mixer, the dope is manufactured.
An apparatus for producing a dope comprising an addition nozzle having a slit-like addition port extending in a diameter direction of a pipe through which the raw material dope flows. The in-line mixer is a static mixer having an element formed by twisting a plate,
The dope manufacturing apparatus according to claim 9, wherein the addition nozzle is arranged so that a longitudinal direction of the addition port and an upstream end of the element are substantially perpendicular.

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