JP5457108B2 - Solution casting method and equipment - Google Patents

Description

  The present invention relates to a solution casting method and equipment for obtaining a polymer film by casting a dope in which a polymer is dissolved in a solvent on a support, and then peeling and drying the dope.

  TAC films formed from cellulose esters, particularly cellulose triacetate (hereinafter referred to as “TAC”) having an average degree of acetylation of 57.5% to 62.5%, are excellent in optical isotropy. Is used as a protective film for polarizing plates of liquid crystal display devices.

  As a method for producing a TAC film, for example, as described in Patent Document 1, a solution casting method is well known. The solution casting method can produce a film having excellent physical properties such as optical properties as compared with other production methods such as a melt casting method. In the solution casting method, a dope is prepared by first mixing a polymer and various additives such as an ultraviolet absorber (UV agent), a matting agent, a retardation control agent, and a plasticizer in a mixed solvent containing dichloromethane and methyl acetate as a main solvent. Prepare. Next, a dope is cast on a support from a casting die to form a casting film. Then, after the cast film becomes self-supporting on the support, the cast film is peeled off as a wet film from the support, dried, and then wound into a roll form as a product film.

  By the way, it is necessary to manufacture the polymer film according to the application. However, it is not realistic to provide a solution casting apparatus for each product type, and it is usual to manufacture a plurality of product types with a single solution film forming facility. Since solution casting equipment cannot produce multiple varieties at the same time, when producing multiple varieties with one solution casting equipment, first produce one varieties. Change the varieties, such as producing other varieties later. There are the following two methods for changing the variety.

  The first method is as follows. First, a new dope in which the type and amount of additive is changed is prepared in a dissolution tank. Next, the prepared new dope is allowed to flow through the film forming line, and the old dope is replaced with the new dope to switch the dope.

  In the second method, a separate charging device is prepared, a new dope is prepared by this separate charging device, and the piping system is switched. This switching eliminates the need to push out the old dope with the new dope, and the pipe capacity for replacing the old dope with the new dope can be reduced, so that the product type can be switched quickly.

  Moreover, in order to finely adjust the addition amount of the additive, the additive solution is added immediately before the additive solution is added immediately before the casting die (see Patent Documents 2 and 3). When the additive is added immediately before casting, the dope is sampled or the finished product is sampled to measure the amount of additive. If the amount of additive is insufficient, an in-line mixer is required. Add the minute just before the casting die. Note that the addition or mixing of additives into the dope by an in-line mixer is also disclosed in Patent Document 4, for example.

Japanese Patent Laying-Open No. 2005-104148 JP 2006-76280 A JP 2007-216674 A JP 2006-085883 A

  There are the above-described first method and second method as a method of switching and manufacturing a plurality of types of films in one solution casting apparatus. However, in the case of the first method of switching the type by replacing the old dope with a new dope of the new formulation, it is not necessary to provide a separate system charging device, but the configuration is simplified, but the extrusion replacement is performed and the replacement is performed. It is necessary to flow a new dope of about three times the pipe capacity until the completion of the process. For this reason, there is a problem that time loss and product loss during extrusion increase.

  Further, in the case of the second method in which a separate system charging device is provided, there is no time loss or product loss unlike the extrusion replacement in the first method, but it is necessary to provide a plurality of additional charging devices. There is a problem that the equipment cost becomes enormous.

  Further, the methods of Patent Documents 2 and 3 in which an additive solution is added to the dope immediately before the casting die are effective when one kind is produced with one film forming equipment. However, when a plurality of varieties are manufactured with one film-forming facility, not only the type of additive to be used but also the timing of adding the additive and the target addition ratio may differ depending on the type of film. Therefore, even if the methods of Patent Documents 2 and 3 are used, it is not sufficient to simply switch the type of additive according to the type of film to be newly produced in these methods. For example, if the additive solution is always added under the same conditions even if the additive solution contained in the solution is changed, the additive solution cannot be mixed so that the dope is in a uniform state. Therefore, until the additive amount of the additive liquid reaches a certain level and the properties of the dope after the additive liquid is added, the film of the target variety cannot be obtained, and the raw materials and production There is a problem of time loss. Further, in some cases, casting is performed in a state where the target additive is insufficient, so that a filming trouble such as a hole is generated in the middle of the film forming, and the casting may be stopped.

  In particular, when the amount of additive liquid added immediately before the dope flow rate is small, both time loss and product loss are large. This is because the pipe leading to the additive nozzle is commonly used regardless of changes in the additive liquid, and the smaller the flow rate of the new additive liquid, the longer it takes to fill the pipe with the new additive. is there. Therefore, this time becomes a loss time, and the dope flowing at this time is not a predetermined ratio, so it cannot be made into a product when it becomes a film. It was connected.

  Therefore, the present invention is for solving the above-described problems. Even when films of different varieties are produced, the production of a solution that suppresses production time and product loss without increasing the cost of the production equipment. An object is to provide a membrane method and equipment. It is another object of the present invention to provide a solution casting method and equipment capable of suppressing manufacturing time and product loss even when the amount of additives to be added to a new variety is small.

The solution casting method of the present invention is based on a casting die when a reference dope preparation step for preparing a reference dope including a polymer and a solvent and a pipe capacity from the reference dope preparation step to the casting die is C1. Te {(1/280) × C1} or more upstream position where the {(1/7) × C1} the following piping capacity, additives specific to each model of the reference doped and hydrogenated pressurized teeth casting dope An adding step, a casting dope is cast on the support by the casting die, and a casting film is formed on the support, and a casting film is provided with self-supporting property and casting. A stripping process for peeling the membrane from the support as a wet film, a drying process for drying the wet film to form a film, and an additive changing process for changing the additive in the adding process according to the product type when changing the product type of the film The adding step is a liquid additive. Including the additive liquid preparation process to prepare the additive liquid by adding it to the inside, the additive liquid is added by the addition nozzle, and the additive change process is added to the standard dope flow rate QD according to the new variety. When the additive flow rate of additive fluid QAE to be added {(QAE / QD) × 100} is 10% or less and the additive fluid flow QAE is 300 × 10 ⁻⁶ m ³ / min or less The addition flow rate QAE is increased by 1.5 to 3.0 times the initial addition flow rate for a certain period of time, and the addition flow rate QAE is set after a lapse of a certain time.

The certain time is preferably a time until the pressure of the additive liquid at the outlet of the addition nozzle becomes the same as the pressure of the reference dope near the outlet of the addition nozzle. Before adding to the reference dope, it has a circulation step of circulating the additive solution in advance, and in this circulation step, the additive solution is preferably circulated at the initial addition flow rate.

Further, the solution casting method of the present invention includes a reference dope preparation step for preparing a reference dope containing a polymer and a solvent, and a casting die when the pipe capacity from the reference dope preparation step to the casting die is C1. based on {(1/280) × C1} or more upstream position where the pipe volume of {(1/7) × C1} or less, Shi added pressure to the specific additives in each model with respect to the reference dope casting A dope adding process, a casting dope is cast on a support by a casting die, a casting film is formed on the support, and a casting film is provided with self-supporting properties Stripping process to peel the membrane from the support as a wet film, drying process to dry the wet film to form a film, and additive changing process to change the additive in the adding process according to the product type when switching the film type In the addition step, the additive is added Including an additive liquid preparation step of adding an additive liquid to the liquid, and adding the additive liquid with an addition nozzle. It has a mixing step of forming a dope and is characterized in that a buffer solution layer is formed on the outer periphery of the additive solution and added to the reference dope.

The buffer solution is either one of the same solution as the solvent component, an additive solution dilution obtained by diluting the additive solution with the same solution as the solvent component, or a reference dope dilution solution obtained by diluting the reference dope with the same solution as the solvent component. It is preferable that In the addition step, the flow rate ratio (QB / QAE) is 0.01 or more and 0.1 or less when the buffer solution is the same solution as the solvent component, the flow rate of the additive solution is QAE, and the flow rate of the buffer solution is QB. It is preferable to do. The mixing step is preferably performed by passing through a plurality of in-line mixers having different mixing methods. The in-line mixer is a second in which a torsion-mixing static mixer configured by arranging a plurality of first elements made of twisted partition members in a reference dope passage and a plurality of elongated partition members alternately intersecting each other. At least one of a split-mix type through-the-mixer configured by arranging a plurality of elements in the reference dope passage and a dynamic mixer configured by arranging a rotating mixer body in the reference dope passage It is preferable.

In the addition step, the ratio of the flow rate of the additive solution to the flow rate of the reference dope is preferably 1% or more and 30% or less. In the addition step, it is preferable to add the additive solution in-line.

The additive contains a plasticizer, and the concentration of the plasticizer in the additive liquid is preferably 10% by weight or more and 65% by weight or less. The reference dope preferably contains additives necessary for each variety.

The reference dope is preferably a pure dope composed of a polymer and a solvent.

It is preferable to have a circulation step of circulating the additive solution in advance before adding the reference dope. In the circulation step, it is preferable to circulate the additive liquid at the same flow rate as that when adding the reference dope to the reference dope. The circulation step is preferably started at least 120 minutes before the start of addition. When changing the type of film, it may have a cleaning step of cleaning the flow path of the additive solution up to the addition nozzle with a cleaning solution made of the same solution as the solvent component before adding the additive solution used for the new type. preferable.

Further, the solution casting apparatus of the present invention includes a reference dope preparation unit for preparing a reference dope including a polymer and a solvent, and a casting capacity when the pipe capacity from the preparation of the reference dope to the casting die is C1. die based on {(1/280) × C1} or more upstream position where the pipe volume of {(1/7) × C1} or less, added Fahrenheit specific additives in each model with respect to the reference dope An additive addition unit to be cast dope and a cast dope to which the additive has been added are cast on a support by a casting die to form a cast film on the support. A new formulation of a film forming unit that gives self-supporting properties and peels the cast film from the support as a wet film, and dries the wet film to obtain a film, and an additive that is added to the standard dope when switching the film type Additive change section to change to The additive addition unit includes an addition nozzle for adding an additive liquid containing the additive to the reference dope, an additive supply unit for preparing an additive liquid to be supplied to the addition nozzle, and the additive liquid. And a mixing part that mixes the reference dope added to make the casting dope uniform, and the addition nozzle has a buffer solution layer forming means for forming a buffer solution layer on the outer periphery of the additive solution. It is configured as.

Additive supply unit, it is not better good with additives circulation means for circulating upstream than the addition nozzle additive solution.

The additive addition unit preferably includes a cleaning unit that cleans the flow path of the additive liquid to the addition nozzle with a cleaning liquid composed of the same liquid as the solvent component when the film type is switched.

The additive supply unit preferably has a flow rate control means for controlling the flow rate of the additive liquid.

  According to the present invention, when producing a new type of film having different components and amounts of various additives, it is possible to suppress the production time loss and product loss without increasing the equipment cost. Furthermore, it becomes possible to efficiently switch the additive, and it is possible to quickly start up to a predetermined addition ratio. Thereby, shortening of the time from the start of the addition of the additive until the quality is stabilized, film formation troubles such as hole opening due to the shortage of the additive are suppressed, and the dope is not wasted. According to the present invention, this effect can be obtained even when the amount of additive used for a new variety is small. Moreover, since the generation of gelation and the aggregation of the additive due to the addition of the additive is suppressed, the product loss is more reliably reduced as a result.

It is the schematic which shows the solution casting apparatus which is 1st Embodiment of this invention. It is the schematic which shows a film forming unit. It is the schematic which shows the addition unit which adds an additive to dope in 2 steps | paragraphs as 2nd Embodiment. It is the schematic which shows the solution casting installation which is 3rd Embodiment of this invention. It is the schematic which shows the solution film-forming equipment which is 4th Embodiment. It is the schematic which shows the additive addition unit of the solution casting installation which is 5th Embodiment. It is the schematic which shows the solution casting installation which is 6th Embodiment. It is a flowchart in 6th Embodiment of this invention which performs addition pre-processing with the initial stage addition flow volume larger than the target addition flow volume. It is a flowchart in 7th Embodiment. It is the schematic which shows the solution casting apparatus which is 8th Embodiment. It is sectional drawing of an addition nozzle. It is a perspective view of the front-end | tip part of an addition nozzle. It is a perspective view of an in-line mixer. It is sectional drawing of a dynamic mixer. It is a graph which shows the relationship between the liquid feeding amount and liquid feeding time of the additive liquid for demonstrating the Example of this invention.

  A solution casting apparatus 10 according to the first embodiment of the present invention shown in FIG. 1 includes a pure dope preparation unit 11, an additive addition unit 12, and a film forming unit 13.

  The pure dope preparation unit 11 includes a mixing unit 15, a dissolving unit 16, a concentration unit 17, and a storage unit 18. The mixing unit 15 includes first and second tanks 21 and 22, a dissolution tank 23, a storage tank 24, and a pump 25. A polymer 26 is placed in the first tank 21, and a predetermined amount of the polymer 26 is weighed by an attached measuring device and charged into the dissolution tank 23. A solvent 27 is placed in the second tank 22, and a predetermined amount of the solvent 27 is charged into the dissolution tank 23 by an attached metering pump (not shown).

  Thus, the dope which consists only of the polymer 26 and the solvent 27 is called pure dope in this invention. For this pure dope, it is necessary for each variety in common, and the minimum addition amount in each variety may be added in advance during the preparation of pure dope. Refer to the second embodiment). Further, pure dope and narrowly-defined reference dope are collectively referred to simply as reference dope.

  The polymer 26 according to the present invention is not particularly limited as long as it can be applied to the solution casting method. Among these, if cellulose acylate is used, a film having high transparency and excellent optical properties can be obtained, so that the obtained film is suitable for optical applications such as a protective film for polarizing plates and an optical compensation film. is there. Among them, when cellulose acetate is used, and particularly TAC having an average value of acetylation degree of 57.5% to 62.5% is used, a film having excellent optical characteristics can be obtained. The above-mentioned degree of acetylation means the amount of bound acetic acid per unit weight of cellulose, and can be determined according to the measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like). In this embodiment, granular TAC is used. In addition, when using a granular polymer, it is preferable that 90 weight% or more is a particle size of 0.1-4 mm from a compatible viewpoint with a solvent, More preferably, a particle size is 1-4 mm. It is.

  The solvent 27 is preferably a halogenated hydrocarbon, an ester, a ketone, an ether, an alcohol, or the like, but is not particularly limited, and may be appropriately selected in consideration of solubility with a polymer to be used. The solvent 27 may be one kind of compound or a mixed solvent in which a plurality of compounds are mixed. Specifically, halogenated hydrocarbons (eg, dichloromethane, etc.), esters (eg, methyl acetate, methyl formate, ethyl acetate, amyl acetate, butyl acetate, etc.), ketones (eg, acetone, methyl ethyl ketone, cyclohexanone, etc.) ), Ethers (eg, dioxane, dioxolane, tetrahydrofuran, diethyl ether, methyl-t-butyl ether, etc.), alcohols (eg, methanol, ethanol, etc.) and the like.

  The dissolution tank 23 is provided with a stirring blade, and the polymer 26 and the solvent 27 in the dissolution tank 23 are stirred by the rotation of the stirring blade. By this stirring, a crude solution in which the solute such as the polymer 26 is not completely dissolved in the solvent is obtained.

  The crude solution in the dissolution tank 23 is temporarily stored in the storage tank 24. As a result, the dissolution tank 23 is emptied, and a continuous batch system in which the crude solution is repeatedly produced batch by batch becomes possible. The storage tank 24 also includes a stirring blade. By rotating the stirring blade, the crude solution is stirred and made uniform.

  The crude solution in the storage tank 24 is sent to the first heater 31 of the dissolution unit 16 via the pump 25. As the first heater 31, an in-line mixer such as a multi-tube heat exchanger or a static mixer is used. The crude solution is heated by the first heater 31. The heating temperature, that is, the temperature of the crude solution by heating is preferably 50 to 120 ° C., and the so-called heating time for maintaining the temperature of the crude solution in this temperature range is preferably 5 to 30 minutes. By this heating, the solute such as the polymer 26 necessary for solution casting is completely dissolved without being modified, and a pure dope is prepared. The pure dope thus prepared is adjusted to 14 to 24% by weight as the solid content concentration of the cellulose ester.

  The pure dope heated by the first heater 31 is sent to the cooler 32. The cooler 32 cools the water to below the boiling point of the main solvent constituting the pure dope. The cooled pure dope is sent to the first filter 34 by the pump 33. The main solvent means a single component when the solvent 27 consists of a single component, and means a liquid component with the largest mass ratio when it consists of a plurality of liquid components.

  Although not shown in the drawings, the first filter 34 includes a plurality of filter main bodies for switching and use, a cleaning device for the filter main bodies, and the like, while performing filtration on the one hand and cleaning and replacing the filter on the other hand. Do. Thereby, continuous filtration of pure dope is enabled. The filtration method is not particularly limited. The pure dope after filtration is sent to the concentration unit 17 by the pump 35.

  The pure dope 44 after filtration is heated by the second heater 40 of the concentration unit 17 and then sent to the flash tank 41, where the pure dope is concentrated by the flash concentration method. The concentrated pure dope is stored in the storage tank 43 of the storage unit 18 by the pump 42. In addition, the concentration part 17 is provided as needed and may be omitted.

  The pure dope 44 stored in the storage tank 43 is sent to the additive addition unit 12 by a pump 45. The additive solution is added inline to the pure dope 44 by the additive addition unit 12. The additive addition unit 12 creates a predetermined additive liquid 67, and supplies the prepared additive liquid 67 to the pure dope 44 flowing through the dope pipe 46, an additive nozzle 51, a static mixer 52, and The second filter 53 is used. In addition, a check valve (not shown) and an open / close valve (not shown) for preventing the backflow of the additive liquid 67 are provided in the pipe for sending the additive liquid 67 to the addition nozzle 51 as necessary. .

  The additive liquid supply unit 50 includes a plurality of additive preparation systems 61, a pump 62, and a controller 63 that prepare an additive liquid that contains a predetermined additive and is used as it is or mixed with the additive liquid 67. I have. The additive preparation system 61 includes an additive preparation unit 64, an additive liquid tank 65, and an opening / closing valve 66a. In some cases, the additive solution prepared by each additive preparation system 61 may be used as it is alone as the additive solution 67, or the additive solution prepared by different additive preparation systems 61 may be mixed to add the additive solution. In some cases, the liquid 67 is used. Thus, by providing the plurality of additive preparation systems 61, it is possible to input a plurality of types of additive liquids 67 into the pure dope 44 according to the film type.

  The types of various additives in the additive liquid 67 and the amount added to the pure dope 44 are determined in advance for each type of film 106 to be manufactured (see FIG. 2), and are stored in the compound look-up table memory (preparation LUT) 68. It is remembered. The controller 63 obtains the type and amount of the corresponding additive from the blending LUT 68 according to the type of the film 106. And the additive liquid made into the additive kind and quantity according to a film kind is prepared by the additive preparation part 64 from the kind and addition amount of the calculated | required additive. This additive solution is stored in each additive solution tank 65. The plurality of additive liquid tanks 65 are provided with additive liquid changing means 66 for adjusting the opening degree of the piping in order to change the additive liquid 67 in accordance with the film type. The additive liquid changing means 66 is composed of a plurality of opening / closing valves 66a, and the opening degree of each of these valves is controlled so that the additive liquid to constitute the additive liquid 67 is sent to the addition nozzle 51 in a predetermined amount. become. Each opening / closing degree of the opening / closing valve 66 a is controlled by the controller 63, whereby the additive liquid 67 to be added to the pure dope 44 is changed, and the additive liquid 67 corresponding to the film type is supplied to the addition nozzle 51 by the metering pump 62. Sent.

  The addition nozzle 51 is a flat nozzle whose tip is flattened and extended in the diameter direction of the circular cross section of the dope pipe 46. The addition nozzle 51 and the static mixer 52 disposed on the downstream side are described in detail in Japanese Patent Application Laid-Open No. 2006-117904, and detailed description thereof is omitted. After the additive solution 67 is uniformly added to the pure dope 44 by the static mixer 52, the foreign substance is removed from the pure dope 44 by the second filter 53, thereby forming the casting dope 54. The casting dope 54 is sent to the casting die 107 (see FIG. 2) of the film forming unit 13.

  In the additive addition unit 12, the addition flow rate ratio of the additive solution 67 to the reference dope, that is, the flow rate of the reference dope when adding the additive solution to the reference dope is QD, and the flow rate of the additive solution 67 when adding. Is a QAE, the percentage (unit:%) obtained by {(QAE / QD) × 100} is preferably 1% or more and 30% or less. In the present embodiment shown in FIG. 1, QD is the flow rate of the pure dope 44.

  In addition, when the addition flow rate ratio of the additive liquid 67 with respect to the reference dope is 0.9%, the additive liquid 67 often needs to have a high concentration by the amount that the addition flow rate ratio is set low. Although gelation may occur at the addition position and a gel failure may occur in the product film 106, the occurrence of gelation is reliably suppressed when the addition flow rate ratio is 1% or more.

  On the other hand, when the ratio of the addition flow rate of the additive solution 67 to the reference dope is 31%, the flow rate QAE of the additive solution 67 becomes larger than the flow rate QD of the reference dope, which causes a problem in the mixing property after addition. However, when the additive flow rate ratio is 30% or less, the reference dope and the additive liquid 67 are mixed and uniform, and the mixing property is reliably improved.

  Further, the ratio (ρ1 / ρ2) of the viscosity ρ1 of the pure dope 44 that is the liquid to be added and the viscosity ρ2 of the additive liquid 67 is preferably 500 or less. If the viscosity ratio exceeds 500 or the addition flow rate ratio exceeds 30%, both are difficult to mix, and if it is less than 1%, efficient addition is not possible although it is mixed.

  Further, the additive contains a plasticizer, and the concentration of the plasticizer in the additive liquid 67 is preferably 10 wt% or more and 65 wt% or less. The concentration of the plasticizer is a percentage (unit:%) obtained by (y / x) × 100, where x is the weight of the additive liquid 67 and y is the weight of the plasticizer. If the concentration is less than 10% by weight, the concentration is too small, and in order to obtain the final required plasticizer amount, it is necessary to increase the amount of additive liquid 67 added to pure dope 44, and the mixing ratio of additive liquid 67 to pure dope 44 May increase, resulting in poor mixing of the two. Moreover, when it exceeds 65 weight%, the additive which does not melt | dissolve in the pure dope 44 will increase.

  In the present invention, for the pure dope 44 to which no additive is added, depending on the film type to be manufactured, the necessary additive is added to the casting die of the film forming unit 13 by the additive liquid supply unit 50 and the addition nozzle 51. Since it is supplied immediately before entering 107, it can respond quickly to new varieties. Thus, the addition is done near the casting die 107 and upstream of the casting die 107. In addition, when supplying the additive liquid 67 to the pure dope 44, the additive contained in the additive liquid 67 is required for each kind including those peculiar to each kind. On the other hand, as in a third embodiment to be described later, an additive common to each type is added to the pure dope 44 in advance, and the additive solution is added to the narrowly-defined reference dope thus obtained. In the case of supplying 67, the additive contained in the additive liquid 67 is an additive specific to each product type.

  Examples of the additive include a plasticizer, a matting agent, an ultraviolet absorber (UV agent), a retardation control agent, and other additives. The additive blending unit 64 identifies various additives necessary for the varieties to be manufactured from the blending LUT 68, mixes the identified additives into the solvent 27 in a necessary amount, and blends the additive liquid 67. These additives are described, for example, in paragraphs [0196] to [0516] of JP-A-2005-104148, and these descriptions can also be applied to the present invention.

  As described above, in the present invention, it is only necessary to change the type of additive liquid 67 and the amount of addition, and in comparison with the conventional method, when the old and new dopes are switched, the previous dope is extruded and replaced with the new dope. The section can be shortened.

  The extruded replacement part is in a state where old and new dopes are mixed. Until the new dope is completely replaced with the conventional equipment in which the additive is added in the mixing section 15, the new capacity is about three times the pipe capacity from the storage tank 24 to the casting die of the film forming unit 13. Requires dope. Therefore, in the case of conventional equipment, by the time the extrusion replacement is completed, a new dope that is about three times the pipe capacity from the storage tank 24 to the casting die does not become a product, and the additive is mixed. Therefore, the film continuously cast by this extrusion replacement cannot be used for recycling. That is, the new dope corresponding to this extrusion replacement amount is wasted. For this reason, the loss of new dope has become enormous in the conventional method for switching new varieties by extrusion replacement. On the other hand, in the present invention, since the additive is added to the reference dope immediately before the casting die 107 (see FIG. 2) of the film forming unit 13, the amount of extrusion substitution can be further reduced.

  In the first embodiment, when the product type is changed, the pipe capacity C2 is 1/280 or more and 1/7 or less with respect to the conventional pipe capacity C1 on the downstream side, that is, the inlet of the casting die of the film forming unit 13. It becomes possible to arrange the addition nozzle 51 at the position. In addition, the film part in which the old and new additives are mixed is about three times the pipe capacity after this addition nozzle, and the dope loss is about 1/280 to 1/7 of that of the conventional equipment. Can be suppressed.

  The pure dope 44 flowing through the dope pipe 46 has a very high viscosity compared to the additive solution 67. For example, the viscosity ρ2 of the additive liquid 67 is approximately 0.001 to 1.0 (unit; Pa · s), whereas the viscosity ρ1 of the pure dope 44 is approximately 10 to 150 (unit; Pa · s). The viscosity ρ2 of the additive liquid 67 is 1 / 150,000 to 1/10 of the viscosity ρ1 of the pure dope. As described above, when the pure dope 44 and the additive liquid 67 having viscosities greatly different from each other are mixed, droplets of the additive liquid 67 are likely to remain in the pure dope 44. That is, minute droplets of the additive liquid 67 are likely to be dispersed in the pure dope 44, and gelation is likely to occur. And this tendency is so large that the flow volume of the additive liquid 67 is small with respect to the flow volume of the pure dope 44 at the time of supplying the additive liquid 67 to the pure dope 44.

  In order to proceed with mixing so that the additive is uniformly dispersed in the pure dope 44 from such a liquid dispersion state, the liquid to be mixed is continuously sent to a plurality of elements. A so-called in-line mixer, for example, a static mixer 52, is effective. However, an in-line mixer such as the static mixer 52 is arranged such that a plurality of elements 52a having a predetermined shape are arranged in the longitudinal direction of the dope pipe 46, as is well known. Since the number of elements 52a is determined so that the additive can be uniformly dispersed in the pure dope 44, the length of the in-line mixer that increases as the number of elements 52a increases is determined by the additive liquid. It is determined according to the viscosity ratio and flow rate ratio between 67 and pure dope, and the longer the viscosity ratio and flow rate ratio, the longer. Further, as the number of elements 52a is increased and the length of the in-line mixer is increased, gelation is more reliably suppressed.

  In this way, in order to supply the additive liquid 67 to the pure dope 44 and uniformly disperse the additive, the additive is evenly dispersed in the static mixer 52 to be used to some extent, that is, by shearing by the element 52a. It needs to be as long as possible. The upstream end of C2 is set more upstream as the static mixer 52 becomes longer.

  In FIG. 1, only one dissolution tank 23 is illustrated, but normally a plurality of dissolution tanks 23 are provided, and the plurality of dissolution tanks 23 are connected to the storage tank 24. In some cases, each dissolution tank 23 is connected to the storage tank 24 with an independent pipe, and only the connection pipe with the predetermined dissolution tank 23 is switched to an open state. In some cases, a switching valve is connected to one pipe connected to the storage tank 24, and a switching valve for switching the crude dissolution liquid from the predetermined dissolution tank 23 to the storage tank 24 is connected to the connection portion. In FIG. 1, the former case is illustrated, and the upstream end of C1 is the downstream end of the dissolution tank 23, that is, the upstream end of the pipe connecting the dissolution tank 23 and the storage tank 24. On the other hand, in the latter case, it is preferable that the connection portion where the pipe extending from each dissolution tank 23 is connected to one pipe is the upstream end of C1.

  Further, some additives used are soluble in the solvent 27. Therefore, conventionally, the additive liquid 67 is added upstream of the first heater 31. Moreover, it is considered preferable that the solvent 27 and the additive come into contact with each other at the earliest possible timing, and the additive liquid 67 is added as upstream as possible. However, since the plurality of dissolution tanks 23 are switched and used as described above in preparing the crude dissolution liquid, the additive liquid 67 can be added to the dissolution tank 23 and the reservoir even at the most upstream side. This is the upstream end of the pipe connecting the tank 24. From this viewpoint, in FIG. 1, the upstream end of the conventional pipe capacity C <b> 1 is illustrated as the downstream end of the dissolution tank 23. On the other hand, when the additive is also mixed in the dissolution tank 23, the upstream end of the dissolution tank 23 may be the upstream end of the conventional pipe capacity C1.

  As described above, the upstream end of the conventional pipe capacity C1 and the upstream end of the pipe capacity C2 are set. Therefore, the range of 1/280 to 1/7 of C2 / C1 is based on these settings.

  In FIG. 1, as described above, the case where the additive solution 67 is added to the crude solution at the upstream end of the pipe connecting the dissolution tank 23 and the storage tank 24 is illustrated with respect to the conventional pipe capacity C1. . In this case, the mixture of the crude solution and the additive solution 67 flowing in the pipe between the dissolution tank 23 and the storage tank 24 is replaced with a mixture of the crude solution and the new additive solution 67. Therefore, the upstream end of the conventional pipe capacity C1 serves as a connection portion between the dissolution tank 23 and the pipe. Therefore, when mixing the crude solution and the additive solution 67 in the dissolution tank 23, the inside of the dissolution tank 23 is replaced with a new mixture, so that the upstream end of the conventional pipe capacity C1 is dissolved. It becomes the upstream end of the tank 23.

  The conventional pipe capacity C1 and the pipe capacity C2 include not only the capacity of the pipes connecting between the devices such as the cooler 32 and the pump 33 and between the tanks, but also the capacity of each equipment and each tank. . That is, all the capacities including the old dope are present.

  If necessary, an online component meter may be provided on the outlet side of the additive liquid tank 65 to measure whether or not the additive component of the additive liquid is within the predetermined range. In this case, according to a measurement result, the addition amount of various additives in the additive preparation part 64 is increased / decreased, and the addition amount of various additive components is controlled within a predetermined range. Near infrared spectroscopy is used for online component measurement.

  Near-infrared spectroscopy is performed by irradiating the additive liquid with near-infrared light in the short wavelength region and detecting the measurement light such as scattered reflected light, scattered transmitted light, or transmitted reflected light from the measured object with an optical sensor. By measuring the absorbance spectrum of the measurement object and obtaining the absorbance in the spectral wavelength region having a correlation inherent to the component amount of the additive solution, the component amount of the additive solution is calculated from the absorbance based on the calibration curve prepared in advance. Is a method of calculating

  As shown in FIG. 2, the film forming unit 13 includes a casting chamber 100, a transfer portion 101, a tenter 102, a drying chamber 103, and a winder 104, and a film 106 using a casting dope 54. Is made. In the casting chamber 100, a casting die 107 in which a discharge port for the casting dope 54 is formed, a casting drum 108 acting as a support, and a peeling roller 109 are arranged.

  The casting dope 54 is cast on a rotating casting drum 108 as an endless casting support through a casting die 107, and a casting film 111 is formed on the peripheral surface. The surface temperature of the casting drum 108 is preferably substantially constant within a range of −10 ° C. to 10 ° C. If the dope is cast on such a casting drum 108, the dope is quickly cooled, so that a gel-like casting film 111 is formed within a short time. As the casting drum 108 rotates, gelation of the casting film 111 proceeds, and the casting film 111 having self-supporting properties is peeled off from the casting drum 108 as a wet film 113 while being supported by the peeling roller 109.

  In the crossover part 101, the wet film 113 is supported by a large number of rollers, and drying proceeds while being transported. In the tenter 102, both end portions of the wet film 113 are held by holding means such as pins, and then dried while being transported to form a film 106. Thereafter, the film 106 is wound up in a roll shape around the core 105 of the winder 104.

  The second filter 53 of the additive addition unit 12 is installed on the upstream side of the casting die 107, and the pure dope 44 mixed with the additive liquid 67 is filtered before being used for casting. Thereby, the casting dope 54 from which impurities are further removed is obtained. In the present embodiment, an apparatus including a metal filter is used, but the filtration method is not particularly limited, and filter paper is also preferably used. Here, the pores of the filter preferably have an average pore diameter of 100 μm or less in order to remove even fine impurities. If the average pore size is too small, the filtration pressure increases, and the pressure limit of the filter may be reached in a short time. On the other hand, if the average pore diameter is too large, it is difficult to capture fine impurities in the casting dope 54. A filter may be appropriately selected in consideration of productivity and the like.

  Solvent recovery from casting chamber 100, casting die 107, casting drum 108, etc. structure, co-casting, peeling method, stretching, drying conditions of each process, handling method, curling, winding method after flatness correction The method and the film recovery method are described in detail in paragraphs [0617] to [0889] of JP-A-2005-104148, and these descriptions can also be applied to the present invention. In the above-described embodiment, the cooling gelation method is adopted in which the casting film is cooled and gelled on the casting drum 108 to have self-supporting property. However, the casting film is dried on the band or the drum to be self-supporting. The present invention can be carried out in the same manner even with a drying method that imparts the property.

  The film obtained by the present invention has high transparency and retardation value and low humidity dependency. Therefore, although it can use suitably as a retardation film of a polarizing plate especially, it can utilize also as a protective film for protecting the surface of a polarizing plate. Regarding specific uses of the cellulose ester film of the present invention, in Japanese Patent Application Laid-Open No. 2005-104148, for example, from [1088] paragraph to [1265] paragraph, as a liquid crystal display device, TN type, STN type, VA type, The OCB type, the reflection type, and other examples are described in detail, and these descriptions can also be applied to the present invention.

  In the continuous production of the film, when changing the kind and amount of various additives and switching the type, the additive addition unit 12 switches from the old additive to the new additive while continuing the casting. First, product type switching information is sent from a master controller (not shown) to the controller 63 of the additive addition unit 12. The type switching information includes switching timing, the type and concentration of additives used for the new type. When the type change information is sent, the controller 63 controls the additive preparation unit 64 so as to make each additive liquid (illustrated) constituting the additive liquid 67 corresponding to the new variety. Further, the controller 63 controls the opening degree of each open / close valve 66a of the additive liquid changing means 66 so that the additive liquid produced by the additive preparation unit 64 is sent from the additive liquid tank 65 to the downstream side. In this way, the additive solution 67 corresponding to the old product is switched to the new product solution 67 by inputting the product switching timing signal to the controller 63. At this time, the old-type additive liquid 67 is discharged and washed, and then a new-type additive liquid 67 is sent to the addition nozzle 51.

  In the first embodiment, single layer casting has been described as an example. In addition to this, in addition to the base layer, co-casting in which outer layers are cast on both surfaces of the base layer simultaneously or sequentially may be used. . Also in this case, as in the above embodiment, first, a pure dope without additives is prepared, and the additive necessary for each layer is added to this pure dope, and the position immediately before the casting die for each layer. Can be added.

  In the case of simultaneous co-casting, a plurality of casting dopes 54 are guided independently to one casting die 107 and merged inside the casting die 107 to be cast independently. A case where a feed block for joining the plurality of cast dopes 54 in a layered manner is provided upstream of the casting die 107, and the plurality of joined dopes 54 are sent to the casting die 107 by a single layered flow; There is. In the latter case using a feed block, the internal flow path of the feed block is also included in the conventional pipe capacity C1 and pipe capacity C2.

  In the case of sequential co-casting, since each casting dope 54 is cast using a plurality of casting dies 107, the upstream end of each casting die 107 is used as the downstream end of the conventional pipe capacity C1. May be used as a reference position for determining the pipe capacity C2.

  In the said 1st Embodiment, although the additive is added in the same addition position, as shown in FIG. 3, you may use the multistage addition unit 70 which adds an additive in multiple positions. The multi-stage addition unit 70 according to the second embodiment is configured by arranging the first addition part 71 and the second addition part 72 apart from the dope pipe 73 in the dope flow direction. The first and second addition units 71 and 72 include an additive liquid supply unit 50, an addition nozzle 51, and a static mixer 52. Further, the multi-stage addition unit 70 includes the same second filter 53 as the additive addition unit 12 downstream of the second addition unit 72.

  This multi-stage addition is effective when the addition is not uniformly performed by a single addition at the same addition position. Note that a plurality of stages may be connected in series, and the number of stages is not particularly limited. The additives at each addition position may be the same component, or additives having different components may be added at each addition position.

  Next, a third embodiment of the present invention will be described with reference to FIG. In this third embodiment, with respect to the pure dope consisting of a polymer and a solvent, the additive used in common for each variety is added in advance by the reference dope preparation unit 80 for the minimum amount of use, and it is narrowly defined. The reference dope 81 is manufactured. In the additive addition unit 82, the shortage is added on the basis of the additive addition amount in the narrowly-defined reference dope 81, but the configuration of the additive addition unit 82 is the same as the additive addition unit 12 of FIG. . In FIG. 4, the additive liquid added by the additive addition unit 82 is denoted by reference numeral 87.

  In the third embodiment, the parts different from the first embodiment are the following three points (1) to (3), and the other configurations are the same as those in the first embodiment. In FIG. The same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. The difference from the first embodiment is that (1) a base additive (common additive) 83 is added from the third tank 84 to the dissolution tank 23 of the mixing unit 85, and the reference dope 81 in a narrow sense is added. (2) In the additive addition unit 82, only the deficiency is added to the additive already added in the narrowly-defined reference dope 81. (3) Furthermore, it is necessary for each film type. It is to add a new additive. Therefore, the additive liquid 87 contains at least one of “deficiency” in (2) and “new additive necessary for each product type” in (3).

  In the third embodiment, when the casting dope 54 having a new formulation that does not require the common additive 83 added when the reference dope 81 in the narrow sense is unnecessary, after the reference dope 81 in the narrow sense is used up, Although there is a demerit that it takes time to switch between the new prescriptions because it is necessary to prepare a narrow standard dope 81 for the new prescription dope, on the other hand, the common additive 83 commonly used is added in the dissolution tank 23 By doing so, there is an advantage that the addition amount in the additive addition unit 82 can be reduced by that amount, and the addition amount in the addition unit 82 can be reduced. The method for adding the common additive 83 is not limited to the third tank 84 but may be added to the dissolution tank 23 by various addition methods.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth to eighth embodiments described below, only aspects different from the first embodiment will be described. In FIG. 5, the same devices and members as those in FIGS. The same reference numerals as in FIGS.

  The solution casting apparatus 90 of the fourth embodiment includes the following additive addition unit 92 in place of the additive addition unit 12 of the first embodiment.

  The pure dope 44 stored in the storage tank 43 of the storage unit 18 is sent to the additive addition unit 92 by the pump 45. The additive addition unit 92 includes an additive liquid supply unit 93, an addition nozzle 51, a static mixer 52, a second filter 53, and a pipe 55 that connects the additive liquid supply unit 93 and the addition nozzle 51. A check valve 56 and an opening / closing valve 57 for preventing the backflow of the additive liquids 99a to 99c are provided in the pipe 55 for feeding the additive liquids 99a to 99c to the addition nozzle 51.

  The additive liquid supply unit 93 includes first to third additive liquid preparation systems 95 to 97 and a controller 98 for these preparation systems 95 to 97. Each of the pipes 180 extending downstream from the additive blending units 170 of the first to third additive liquid blending systems 95 to 97 includes a three-way switching valve 179b described later, and this three-way switching valve 179b. It connects to the piping 55 connected to the addition nozzle 51 downstream. Thus, by providing the plurality of additive liquid preparation systems 95 to 97, a plurality of types of additive liquids 99a to 99c can be added to the pure dope 44 as much as necessary depending on the film type. In this embodiment, three additive liquid preparation systems 95 to 97 are provided, but these may be two or more.

  The first additive liquid blending system 95 is for adding a plasticizer. The additive liquid blending section 170 and a metering pump that sends the additive liquid 99a produced by the additive liquid blending section 170 to the downstream side. 172 and a circulation part 173 are provided. The additive liquid preparation unit 170 is connected to the pipe 55 as described above, and stirs and mixes the plasticizer supply unit 174, the solvent supply unit 175, and the plasticizer and the solvent supplied from the supply units 174 and 175. A mixing tank 176 and an additive liquid tank 177 are provided. Each supply part 174,175 is connected to each additive tank and solvent tank which are not shown in figure, and an additive and a solvent are measured and supplied to the mixing tank 176. The mixing tank 176 prepares an additive liquid 99a by adding a plasticizer to the solvent in an amount determined for each film type in accordance with the type of TAC film. The additive agent 99a has a plasticizer concentration of, for example, 25% by weight and a viscosity of 10 mPa · s. This plasticizer concentration is preferably used in the range of 10 wt% to 65 wt%. The plasticizer viscosity is preferably used within a range of 10,000 mPa · s or less.

  The second additive liquid preparation system 96 prepares an additive liquid 99b in which a UV agent and a solvent are mixed. Further, the third additive liquid preparation system 97 prepares an additive liquid 99c in which a retardation control agent and a solvent are mixed. These second and third additive liquid preparation systems 96 and 97 are configured in the same manner as the first additive liquid preparation system 95.

  The types and amounts of various additives such as plasticizers, UV agents, retardation control agents, and matting agents added to the pure dope 44 are determined in advance for each type of film to be manufactured. LUT) 167 is stored in the controller 98. The controller 98 obtains the type and amount of the corresponding additive from the blending LUT 167 according to the film type. Then, additive liquids 99a to 99c are prepared by the additive liquid preparation unit 170 based on the obtained types and amounts of additives. The prepared additive liquids 99a to 99c are stored in each additive liquid tank 177.

  Each circulation part 173 includes a circulation pipe 178 and three-way switching valves 179a and 179b for circulating the additive liquids 99a to 99c upstream of the connection part between the pipe 55 and the pipe 180. The circulation pipe 178 is connected to a pipe 180 that connects the additive liquid preparation unit 170 and the pump 172, and a three-way switching valve (hereinafter referred to as an inlet-side three-way switching valve) 179a is provided at this connection part. That is, the inlet side three-way switching valve 179 a is provided in the pipe 180 between the additive liquid preparation unit 170 and the pump 172. The pipe extending downstream from the first additive liquid blending system 95 and provided with the pump 172 is connected to the pipe 55 as described above, and branches to the circulation pipe 178 upstream from this connecting portion. The aforementioned three-way switching valve (hereinafter referred to as an outlet-side three-way switching valve) 179b is provided at this branching portion.

  As for these inlet side three-way switching valve 179a and outlet side three-way switching valve 179b, the opening degree of the three valves is adjusted independently. This opening degree adjustment includes switching between opening and closing, and the flow paths of the additive liquids 99a to 99c are switched by switching between opening and closing. For example, when the outlet-side three-way switching valve 179b closes only the valve on the circulation pipe 178 side, the additive liquids 99a to 99c of the additive liquid preparation unit 170 do not flow into the circulation pipe 178 and are added through the pipe 55. 51. When the outlet side three-way switching valve 179b closes only the valve on the connection portion side with the pipe 55, the additive liquids 99a to 99c flow to the circulation pipe 178 without being sent to the addition nozzle 51, and the additive It flows so that it circulates through the piping 180 extended downstream from the liquid preparation part 170, and the circulation piping 178 branched from here. Moreover, when opening the predetermined valves of the inlet side three-way switching valve 179a and the outlet side three-way switching valve 179b, the flow rate and pressure of each of the additive liquids 99a to 99c to be flowed are adjusted by adjusting the opening degree. Is controlled.

  When each of the three-way switching valves 179a and 179b receives a switching timing signal for the next new product, the opening of the valve is switched based on the switching timing signal. By this switching, the additive liquids 99a to 99c used for the new variety are flowed to the circulation pipe 178 at a predetermined flow rate before the addition timing, and the additive liquid 99a is circulated through the circulation pipe 178 and the pipe 180. The pre-circulation process for flowing ~ 99c is started. Thereafter, at a predetermined timing, the opening degree of each of the three-way switching valves 179a and 179b is switched again, and the additive liquids 99a to 99c to be sent to the addition nozzle 51 are caused to flow through the pipe 55 at a predetermined flow rate. . In this way, the pre-circulation treatment that is circulated before the addition to the pure dope 44 and the preparation of the additive solution to be added to the pure dope 44 are performed. The pre-circulation time is preferably in the range of 120 minutes to 1440 minutes, particularly preferably 150 minutes to 720 minutes.

  The pre-circulation time is set to 120 minutes and the pre-circulation process is performed before the addition so that the circulation starts 120 minutes before the addition start timing signal. In order to determine the pre-circulation time, it was tried by changing various values between 60 minutes and 300 minutes. If it is less than 120 minutes, the additive may not be uniform and the product may become uneven. was there. Further, when it exceeds 240 minutes, there is no particular problem in terms of the product, but it becomes an excessive operation time and is not a preferable value from the viewpoint of running cost and the like. Therefore, the pre-circulation time is preferably 120 minutes or more and 1440 minutes or less, and particularly preferably 150 minutes or more and 720 minutes or less.

The circulation flow rate in the circulation unit 173 is the same as the addition flow rates of the additive liquids 99a to 99c. The addition flow rate is set as a flow rate ratio with respect to the pure dope 44. When the addition flow rate of the additive liquid having an additive concentration of 1% when the pure dope 44 is 20 L / min, 200 cc is set. It is circulated in the circulation part 173 at a flow rate of / min (= 200 × 10 ⁻⁶ m ³ / min). Then, the opening / closing valve is opened by the addition start timing signal to the pure dope 44, and the additive liquids 99a to 99c are added to the pure dope 44 from the addition nozzle 51 in the same amount as the circulation flow rate. In this way, by performing the pre-circulation process at the same flow rate as at the time of addition, the flow rate at the time of pre-circulation process and the flow rate at the time of addition become the same, so it moves in the process of switching from circulation to addition The only thing is a valve. For this reason, there is no occurrence of pulsation, and the additive switching time for suppressing the occurrence of pulsation becomes unnecessary. On the other hand, in the conventional switching process, since the flow rate is adjusted after the addition start timing signal is input, the pressure also varies and the flow rate also varies. Therefore, pulsation and pressure fluctuation are large, and it takes a long time to adjust. During this adjustment time, since the casting dope has not reached the content of the additive necessary for the product, the film with the casting dope during this time cannot be a product and is wasted. In the present invention, this adjustment time is not necessary, so that the loss time is reduced accordingly, and the waste of casting dope is reduced.

  The other additive liquid blending systems 96 and 97 are configured in the same manner, and the same components are denoted by the same reference numerals. The circulation unit 173 configures the circulation unit 173 with the on-off valve 57 closed until the newly prepared additive liquids 99a to 99c are added to the pure dope 44, and the additive liquid 65a is formed in the circulation unit 173. Circulating ~ 65c and waiting.

  A cleaning liquid supply unit 182 is connected to the circulation unit 173 via an on-off valve 181. The cleaning liquid supply unit 182 sends a solvent as a cleaning liquid to the circulation unit 173 at the time of product type switching, and cleans the previously supplied additive solution. The cleaning liquid after cleaning is discharged from the addition nozzle 51, and the parts from the additive liquid supply unit 93 to the addition nozzle 51 are cleaned. After the cleaning, each additive liquid preparation system 95 to 97 sends the new additive liquids 65a to 65c for the next variety after the opening / closing valve 57 is closed, and circulates it in the circulation unit 173. In addition, the film | membrane by casting dope in the kind change operation in which this washing | cleaning liquid is discharged from the addition nozzle 51 does not become the predetermined additive addition amount, and is excluded from a product. As described above, at the time of product type switching of the film 106, among the additive liquid supply unit 93, the additive liquids 99a to 99c added to the film 106 before switching and the additive liquid 99a added to the film 106 after switching. The pipe through which -99c flows is washed with a washing liquid.

  The addition nozzle 51 is the same flat nozzle as in the first embodiment. After the additive liquids 99a to 99c are uniformly added to the pure dope 44 by the static mixer 52, the pure dope 44 has the foreign matter removed by the second filter 53 in the same manner as in the first embodiment, and becomes the casting dope 54. . Then, the casting dope 54 is sent to the casting die 107 (see FIG. 2) of the film forming unit 13.

  In the fourth embodiment, as in the first embodiment, the necessary additives are added to the additive liquid supply unit 93 and the addition nozzle according to the type of film to be manufactured with respect to the pure dope 44 to which no additive is added. Since it is supplied by 51, it is possible to respond quickly to new varieties.

  The additive liquid blending unit 170 identifies various additives necessary for the varieties manufactured from the blending LUT 167, and adds and mixes the identified amounts of the identified additives into the solvent 27 to prepare the additive liquid.

  Thus, when the casting dope 54 containing mutually different additives is manufactured by switching with one solution film-forming equipment 90, it is only necessary to change the types of additive liquids 99a to 99c and their addition amounts. As before, when switching between old and new dopes, the section in which the previous dope is pushed and replaced by the new dope can be shortened.

  Also in the fourth embodiment, when the product type is switched, the addition nozzle 51 is arranged at a position where the pipe capacity C2 is 1/280 to 1/7 of the conventional pipe capacity C1 with respect to the downstream side. For this reason, similarly to the first to third embodiments, the dope loss can be suppressed to about 1/280 to 1/7 of that of the conventional equipment.

  On the outlet side of the additive liquid tank 177, as with the outlet side of the additive liquid tank 65 (see FIG. 1), an online component meter is provided as necessary, so that the additive component of the additive liquid is added. You may measure whether it is in a predetermined range. In this case, according to the measurement result, the amount of various additives added in the mixing tank 176 is increased or decreased, and the various additive components are controlled within a predetermined range.

  The additive addition unit 92 includes the second filter 53 as in the additive addition unit 12 of the first embodiment. By this second filter 53, the pure dope 44 to which the additive liquids 99a to 99c are added is filtered on the upstream side of the casting die 107 before being subjected to casting. Thereby, the casting dope 54 in the third embodiment also has impurities removed further.

  In the continuous production of the film 106, when changing the type and amount of various additives and switching the product type, the additive addition unit 92 switches from the old additive to the new additive while continuing the casting. . First, when the product type switching information is sent from a master controller (not shown) to the controller 98 of the additive addition unit 92, the controller 98 prepares additive liquids 99a to 99c corresponding to the new variety. In addition, the controller 98 inputs the type change timing signal of the additive liquids 99a to 99c corresponding to the old type among the type change information sent, and the controller 98 adds the additive liquid to be added to the pure dope 44 at this change timing. In order to enable switching, discharging and washing of the old-type additive liquids 65a to 65c and circulation of the new-type additive liquids 65a to 65c are performed. Then, the three-way switching valves 179a and 179b are switched again by the type switching timing signal, and the circulation is stopped and the on-off valve 57 provided in the pipe 55 extending to the adding nozzle 51 is opened, and a new kind of additive liquid is added. 51 to pure dope 44 is added.

  In the fourth embodiment, various additive liquids 99a to 99c are added to the pure dope 44 using one addition nozzle 51. Instead of this, as shown in FIG. The additive addition unit 187 may be used in which the additive liquid is added at different positions with respect to the pure dope 44 using the four addition nozzles 185a to 185d. In the case of the fifth embodiment, additive liquid supply units 186a to 186d are provided for each additive liquid. The additive liquid supply units 186a to 186d are configured in the same manner as the additive liquid supply unit 93 of the fourth embodiment, but the additive liquid preparation system has only one system corresponding to each additive. . A plurality of additive liquid supply units 93 capable of supplying a plurality of types of additive liquids according to the fourth embodiment may be used as the additive liquid supply units 86a to 86d. In FIG. 6, the same components as those in the first to fourth embodiments are denoted by the same reference numerals as those in FIGS. 1 to 5, and redundant descriptions are omitted.

  The solution casting apparatus 210 of the sixth embodiment shown in FIG. 7 includes a pure dope preparation unit 11, an additive addition unit 212, and a film forming unit 13. In FIG. 7, the same components as those in the first to fifth embodiments are denoted by the same reference numerals as those in FIGS. 1 to 6, and redundant description is omitted.

  The pure dope 44 stored in the storage tank 43 of the storage unit 18 is sent to the additive addition unit 212 by the pump 45. The additive addition unit 212 includes first to fourth additive liquid supply units 247 to 250, addition nozzles 51 a to 51 d, a static mixer 52, a second filter 53, and a controller 258. A check valve 56 and an opening / closing valve 57 for preventing the backflow of the additive liquids 261a to 261d are provided in the pipe 255 for feeding the additive liquids 261a to 261d to the addition nozzles 51a to 51d.

  The 1st additive liquid supply part 247 is for adding a plasticizer, and is for sending the additive liquid 261a from this additive liquid preparation part 170 and this additive liquid preparation part 260 to the addition nozzle 51a. A liquid feeding unit 262 is provided. The liquid feeding unit 262 includes a pump 263, a pipe 264, and a circulation unit 265.

  The additive liquid preparation unit 170 is the same as that in the fourth embodiment shown in FIG. 5, and the plasticizer and solvent supplied from the plasticizer supply unit 174, the solvent supply unit 175, and the supply units 174 and 175. Are mixed with a mixing tank 176 and an additive liquid tank 177. The plasticizer concentration of the additive liquid 261a adjusted in the mixing tank 176 is, for example, 25% by weight, and the viscosity is 10 mPa · s. This plasticizer concentration is preferably used in the range of 10 wt% to 65 wt%. The plasticizer viscosity is preferably used within a range of 10,000 mPa · s or less.

  The circulation unit 265 includes a circulation pipe 268 and three-way switching valves 266 and 267. Further, a cleaning liquid supply unit 270 is connected to the circulation pipe 268 via an on-off valve 269. The inlet side three-way switching valve 266 is provided in a pipe 264 that connects the additive liquid preparation unit 170 and the pump 263. The outlet side three-way switching valve 267 is provided in the liquid supply pipe 255 of the first additive liquid supply unit 247. When the next new product type switching timing signal is input to the three-way switching valves 266 and 267, the valve opening degree is switched in the same manner as in the fourth embodiment based on the switching timing signal. By this switching, the additive liquids 261a to 261d used for the new variety are started to be pre-circulated at a predetermined flow rate prior to the addition timing. Thereafter, at a predetermined timing, the opening degree of each of the three-way switching valves 266 and 267 is switched again, and the additive liquids 261a to 261d to be added to the pure dope 44 are added at a predetermined flow rate. 51d. In this way, preparation of the additive liquids 261a to 261d and pre-circulation processing are performed. The pre-circulation time is preferably in the range of 120 minutes to 240 minutes, and particularly preferably 150 minutes to 210 minutes.

The circulation flow rate in the circulation unit 265 is the same as the addition flow rate of the additive liquid 261a. The addition flow rate is set as a flow rate ratio with respect to the pure dope 44. When the addition flow rate of 1% additive liquid is set when the pure dope 44 is 20 L / min, 200 cc / min (= 200 It is circulated in the circulation part 265 at a flow rate of × 10 ⁻⁶ m ³ / min). Then, the opening / closing valve is opened by the addition start timing signal to the pure dope 44, and the additive liquid 261a is added from the addition nozzle 51a in the same amount as the circulation flow rate. Thus, also in the sixth embodiment, by performing the standby circulation operation at the same flow rate to be added, the flow rate during the standby circulation operation and the flow rate during the addition become the same, so the switching process from circulation to addition is performed. The only thing that moves is the valve. For this reason, there is no occurrence of pulsation, and the additive switching time for suppressing the occurrence of pulsation becomes unnecessary. Therefore, the loss time is reduced as much as this adjustment time becomes unnecessary, and the waste of casting dope is reduced.

  By the way, when the addition flow rate of the additive liquid 261a is small compared to the flow rate of the pure dope 44, even if it is circulated and waits as described above and then switched at a predetermined timing, it will continue until a predetermined pressure is reached. It takes a long time, and the switching time becomes longer compared to the usual addition. If switching takes a long time, efficient switching becomes impossible. In addition, during the switching time, since the casting dope has not reached the content of the additive necessary for the product, the film by casting dope during this time cannot be a product and is wasted. Such production time loss and product loss are larger as the additive flow rate of the additive liquid 261a is smaller than the pure dope 44 flow rate.

Therefore, in the sixth embodiment, in order to shorten the adjustment time when a small amount is added, as shown in FIG. 8, the amount of additive liquid added is less than a predetermined amount (“A” in FIG. 8) at the time of product type switching. Specifically, it is the additive flow rate (target value) QAE addition flow rate ratio of the additive liquid to be switched in accordance with the new product type with respect to the dope flow rate QD {(QAE / QD) × 100} (Unit:%) is 10% or less, and when the addition flow rate QAE is 300 cc / min or less (= 300 × 10 ⁻⁶ m ³ / min), the addition flow rate QAE is 1.5 times or more. Increased addition is performed for a certain time at an initial addition flow rate QAS of 0 times or less. The flow rate is changed from QAS to QAE, which is a target value, after the predetermined time has elapsed. If the initial addition flow rate QAS is less than 1.5 times the addition flow rate QAE, the effect of time reduction is small, and if it exceeds 3.0 times the addition flow rate QAE, pulsation occurs when returning to the target addition flow rate. In addition, it is necessary to use a liquid pump having a large capacity, which is disadvantageous in terms of equipment. In this way, it is preferable to perform an increase addition of flowing the additive liquid at a flow rate larger than the target addition flow rate QAE for a certain period of time, and to reduce the flow rate to the addition flow rate QAE that is the target value after a certain time has elapsed.

  The predetermined time is a time until the pressure of the additive liquid 261a at the outlet of the addition nozzle 51a becomes the same as the pressure of the pure dope 44 near the outlet of the addition nozzle 51a. For this time, a representative value obtained in advance by experiments or the like is stored in the LUT memory 258a for each additive solution, and an increased amount can be added based on the stored time. Further, instead of using the representative value stored in advance, the pressure of the additive liquid 261a is measured by a pressure gauge provided near the outlet of the addition nozzle 51a as in the seventh embodiment shown in FIG. The certain time may be changed based on the value. The predetermined time is changed based on the measured pressure value, that is, when the measured pressure value of the additive liquid 261a becomes the same as the pressure of the pure dope 44 in the vicinity of the outlet of the addition nozzle 51a, the previously predicted The addition of the increased amount is terminated regardless of the fixed time.

  As described above, the “predetermined time” for carrying out the increased addition is most preferably the time until the pressure of the additive liquid 261a at the outlet of the addition nozzle 51a becomes the same as the pressure of the pure dope 44. However, even if the setting of the flow rate of the additive solution 261a is changed from the initial addition flow rate QAS to the addition flow rate QAE, the pressure at the outlet of the addition nozzle 51a of the additive solution 261a does not become constant immediately when the flow rate is changed. There is a time difference between when the flow rate setting is continued and the flow rate setting is changed and when the rising pressure becomes constant, and it may be difficult to set this time difference to 0 (zero). For example, in such a case, considering the time difference, etc., before reaching the same pressure as that of the pure dope 44 near the outlet of the addition nozzle 51a, that is, within a pressure smaller than the pressure of the pure dope 44. It is advisable to end the increase addition. That is, according to the time difference or the like, the “certain time” may be set to a time shorter than the time until the pressure of the additive liquid 261a reaches the same pressure as the pressure of the pure dope 44.

  In the LUT memory 258a, the additive liquid addition amount for each product type is obtained and stored in advance, so that it is not necessary for the operator to input the additive liquid flow rate of various additive liquids, and setting due to an input operation error. The value is correct. For this reason, in the case of a set value miss, the dope in the section of the set value miss is wasted, but such a waste can be eliminated.

  Further, when the addition flow rate ratio {(QAE / QD) × 100} of the additive flow QAE of the additive liquid to be switched in accordance with the new variety exceeds the flow rate QD of the pure dope 44 which is the reference dope Does not need to be circulated at the increased initial addition flow rate QAS or increased addition treatment as described above, and circulates at the addition flow rate QAE for a certain period of time. The predetermined time is obtained in advance by experiments or simulations and stored in the LUT memory 58a of the controller 258. As described above, the circulation process can reduce the dope addition time (loss time) in the state where the additive is mixed in the middle of switching, and the waste of casting dope is reduced.

  In the LUT memory 258a, in addition to the predetermined time, the types and amounts of various additives such as a plasticizer, a matting agent, a UV agent, and a retardation control agent added to the pure dope 44 are stored. The types and amounts of these various additives are determined in advance for each type of film 106 to be manufactured. The controller 258 obtains the type and amount of the corresponding additive from the LUT memory 258a according to the film type. And based on the kind and addition amount of the calculated | required additive, the additive liquid preparation part 170 prepares the additive liquid 261a-261d. The prepared additive liquids 261a to 261d are stored in each additive liquid tank 177. Also, the presence / absence of the increase addition process, the increase ratio at the increase addition process, and the like are obtained in advance by experiments and stored in the LUT memory 258a.

  Other 2nd-4th additive liquid supply parts 248-250 are also comprised similarly to the 1st additive liquid supply part 247, and abbreviate | omit detailed description. The second additive liquid supply unit 248 prepares an additive liquid 261b in which a matting agent and a solvent are mixed. The third additive liquid supply unit 249 prepares an additive liquid 261c in which a UV agent and a solvent are mixed. The fourth additive liquid supply unit 250 prepares an additive liquid 261d in which a retardation control agent and a solvent are mixed.

  In this way, by providing a plurality of additive liquid supply units 247 to 250 corresponding to the types of necessary additives, a plurality of types of additive liquids 261a to 261d corresponding to the necessary film types are each purely doped 44 as much as necessary. Can be put in. In the present embodiment, the four additive liquid supply units 247 to 250 are provided, but these need only be provided.

  The circulation unit 265 circulates by the three-way switching valves 266 and 267 and the circulation pipe 268 and waits until the newly prepared additive solutions 261a to 261d start to be added to the pure dope 44.

  Further, a cleaning liquid supply unit 270 is connected to the circulation unit 265 via an on-off valve 269. The cleaning liquid supply unit 270 sends the solvent to the circulation unit 265 at the time of product type switching, and cleans the additive liquid supplied previously. The cleaning liquid after cleaning is discharged from the addition nozzle 51a, and the first additive liquid supply unit 247 to the addition nozzle 51a are cleaned. After the cleaning, the additive liquid preparation unit 170 closes the on-off valve 57, and then sends new additive liquids 261a to 261d for the next variety and circulates them in the circulation unit 265. In addition, the film | membrane by casting dope in the kind change operation in which this washing | cleaning liquid is discharged from the addition nozzle 51a does not become the predetermined additive addition amount, and is excluded from a product.

  Other 2nd-4th additive liquid supply parts 248-250 are also comprised similarly to the 1st additive liquid supply part 247, and abbreviate | omit detailed description. The second additive liquid supply unit 248 prepares an additive liquid 261b in which a matting agent and a solvent are mixed. The third additive liquid supply unit 249 prepares an additive liquid 261c in which a UV agent and a solvent are mixed. The fourth additive liquid supply unit 250 prepares an additive liquid 261d in which a retardation control agent and a solvent are mixed.

  In this way, by providing a plurality of additive liquid supply units 247 to 250 corresponding to the types of necessary additives, a plurality of types of additive liquids 261a to 261d corresponding to the necessary film types are each purely doped 44 as much as necessary. Can be put in. In this embodiment, four additive liquid supply units 247 to 250 are provided, but these may be increased or decreased as appropriate.

  The addition nozzles 51a to 51d are the same flat nozzles as the addition nozzle 51 of the first embodiment whose tip is flattened. The addition nozzles 51 a to 51 d are arranged in the dope pipe 46 so that the tip flat portion is aligned with the diameter direction of the dope pipe 46. The static mixer 52 arranged on the downstream side of the addition nozzles 51a to 51d is arranged so that a large number of elements 52a formed by twisting a rectangular plate at 180 degrees are arranged in series in the pipe, so that the addition nozzle for the pure dope is added. Various additive liquids added by 51a to 51d are dispersed and mixed. The pure dope 44 having passed through the static mixer 52 is removed by the second filter 53 to become a casting dope 54. The casting dope 54 is sent to the casting die 107 (see FIG. 2) of the film forming unit 13.

  In the sixth embodiment, necessary additives are supplied to the pure dope 44 to which no additive is added by the additive liquid supply units 47 to 50 and the addition nozzles 51 a to 51 d according to the film type to be manufactured. Therefore, it is possible to respond quickly to new varieties.

  In the additive liquid blending unit 170, various additives necessary for the varieties manufactured from the LUT 258a are specified, and the specified additive is added to the solvent 27 in a necessary amount and mixed to prepare the additive liquid.

  Thus, also in the sixth embodiment, it is only necessary to change the type of additive liquid and the amount of addition, and as before, when the old and new dopes are switched, the previous dope is extruded and replaced with the new dope. The section can be shortened.

  The extruded replacement part is in a state where old and new dopes are mixed. Also according to the sixth embodiment, the addition nozzles 51a to 51d are arranged at positions where the pipe capacity C2 is 1/280 to 1/7 of the conventional pipe capacity C1 with respect to the downstream side at the time of product type switching. For this reason, the film part in which the old and new additives are mixed is about three times the pipe capacity after the addition nozzle, and the dope loss is 1/280 to 1/7 of that of the conventional equipment. It can be suppressed to the extent.

  Also in the sixth embodiment, an online component meter may be provided on the outlet side of the additive liquid tank 177 to measure whether the additive component of the additive liquid is within a predetermined range. And according to a measurement result, it is good to increase / decrease the addition amount of the various additives in the mixing tank 76, and to control various additive components within the predetermined range.

  The additive addition unit 212 includes the second filter 53 as in the additive addition unit 12 of the first embodiment. By the second filter 53, the pure dope 44 to which the additive liquids 261a to 261d have been added is filtered upstream of the casting die 107 before being cast. As a result, the casting dope 54 in this embodiment also has impurities removed further.

  In the continuous production of the film 106, when changing the type and amount of various additives and switching the product type, the additive addition unit 212 switches from the old additive to the new additive while continuing the casting. . First, when the product type switching information is sent from a master controller (not shown) to the controller 258 of the additive addition unit 212, the controller 258 controls each unit so as to prepare additive liquids 261a to 261d corresponding to the new variety. . In addition, the additive liquids 261a to 261d corresponding to the old varieties are discharged, washed, and new varieties of the old varieties of additive liquids 261a to 261d so that they can be switched at this switching timing by inputting the type switching timing signal. The additive liquids 261a to 261d are circulated. Then, the three-way switching valves 266 and 267 are switched by the type switching timing signal to stop the circulation, and the on-off valve 57 is opened to add a new type of additive liquid into the pure dope from the addition nozzles 51a to 51d.

  In the fifth embodiment, various additive liquids 261a to 261d are added to the pure dope 44 using the respective addition nozzles 51a to 51d provided corresponding to the respective additive liquid supply units 247 to 250. However, instead of this, although not shown in the figure, for example, an additive addition unit in which the additive liquid is added to the pure dope 44 at the same position by using one addition nozzle may be used. .

  In the sixth embodiment, it is determined whether or not the amount of time for increasing the initial addition flow rate QAS has reached a predetermined time, and after the predetermined time has elapsed, the initial addition flow rate QAS is changed to the addition flow rate QAE. However, the timing of this change is that the pressure near the outlet of the addition nozzle is detected by a pressure sensor as in the seventh embodiment shown in FIG. 9, and this detected pressure Pa reaches, for example, 90% of the set pressure P1. The initial addition flow rate QAS may be changed to the addition flow rate QAE.

  The solution casting apparatus 310 of the eighth embodiment shown in FIG. 10 includes a pure dope preparation unit 11, an additive addition unit 312, and a film forming unit 13. In FIG. 10, the same components as those in FIGS. 1 to 10 as the first to seventh embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  The pure dope (reference dope) 44 stored in the storage tank 43 of the storage unit 18 is sent to the additive addition unit 312 by the pump 45. The additive addition unit 312 includes a dope pipe 46 through which the pure dope 44 flows, first to fourth additive liquid supply units 247 to 250 similar to the sixth embodiment, addition nozzles 51a to 51d, an in-line mixer 352, a first 2 filters 53 and a controller 358. A check valve 56 and an open / close valve 57 for preventing the backflow of the additive liquids 261a to 261d are provided in each pipe 355 for feeding the additive liquids 261a to 261d to the addition nozzles 51a to 51d.

  In the LUT memory 358a, as in the LUT memory 258a of FIG. 7, the additive liquid addition amount for each type is obtained and stored in advance.

  In addition, the circulation processing time before the addition of the additive solution is obtained in advance by experiments or simulations, and these are stored in the LUT memory 358a of the controller 358. As described above, the circulation process can reduce the dope addition time (loss time) in the state where the additive is mixed in the middle of switching, and the waste of casting dope is reduced.

  In the LUT memory 358a, in addition to the predetermined time, types and amounts of various additives such as a plasticizer, a matting agent, a UV agent, and a retardation control agent added to the pure dope 44 are stored. The type and amount of these various additives are determined in advance for each type of film to be produced. The controller 358 determines the type and amount of the corresponding additive from the LUT memory 358a according to the film type. And based on the kind and addition amount of the calculated | required additive, the additive liquid preparation part 170 prepares the additive liquid 261a-261d. The prepared additive liquids 261a to 261d are stored in each additive liquid tank 177. Also, the presence / absence of the increase addition process, the increase ratio at the increase addition process, and the like are obtained in advance by experiments and stored in the LUT memory 358a.

  Other 2nd-4th additive liquid supply parts 248-250 are also comprised similarly to the 1st additive liquid supply part 247, and abbreviate | omit detailed description. The second additive liquid supply unit 48 prepares an additive liquid 61b in which a matting agent and a solvent are mixed. The third additive liquid supply unit 49 prepares an additive liquid 61c in which a UV agent and a solvent are mixed. The fourth additive liquid supply unit 50 prepares an additive liquid 61d in which a retardation control agent and a solvent are mixed.

  In this way, by providing a plurality of additive liquid supply units 47 to 50 corresponding to the necessary types of additives, a plurality of types of additive liquids 61a to 61d corresponding to the necessary film types are added to the addition nozzle 51a. To 51d can be put into the pure dope 44 (pipe 46 for dope). In this embodiment, four additive liquid supply units 47 to 50 are provided, but these may be increased or decreased as appropriate. In the present embodiment, an in-line mixer 352 is provided on each downstream side of the addition nozzles 51a to 51d.

  As shown in FIGS. 11 and 12, the addition nozzle 51a has a double piping structure including an inner tube 380 and an outer tube 381, and the outer peripheral surface of the inner tube 380 through which the additive liquid 61a flows and the inner periphery of the outer tube 381. An outer passage 384 through which the buffer solution 387 flows is formed between the surfaces. A first additive solution supply unit 247 is connected to the inner passage 383 of the addition nozzle 51a, and a buffer solution supply unit 385 for supplying the buffer solution 387 to the outer passage 384 is connected to the outer passage 384. Yes.

  The buffer solution supply unit 385 includes a solvent supply unit 375 and a liquid feed pump 386, and the liquid feed pump 386 uses the same liquid as the component of the solvent 27 in the second tank 22 (see FIG. 10) as a buffer solution 387. Supply to passage 384. By supplying the buffer solution 387 to the outer passage 384, a buffer solution layer 389 a composed of the buffer solution flow 389 is formed on the outer periphery of the additive solution flow 388 at the boundary with the pure dope flow 44 a. The buffer solution layer 389a mixes the additive solution 261a and the buffer solution 387, and the buffer solution 387 and the pure dope 44 little by little. Therefore, when the additive solution 261a is in direct contact with the pure dope 44 and mixed. In comparison, gelation and condensation of additives do not occur. Thus, the buffer solution 387 is used to form the buffer solution layer 389a that suppresses buffering between the additive solution 261a and the pure dope 44 at the time of addition. When reaching the static mixers 392 and 393 (see FIG. 13) of the in-line mixer 352, the pure dope 44, the buffer solution 387, and the additive solution 261a are dispersed and mixed in the elements 394a, 394b, 395a, and 395b. Similarly, no gelation or aggregation of additives occurs. The distal end portion of the inner tube 380 is formed in a tapered shape in which the diameter of the inner peripheral surface having a circular cross section is constant in the longitudinal direction, whereas the outer peripheral surface is smaller in diameter toward the distal end. Thereby, the buffer solution layer 389a is more reliably formed around the additive solution flow 388.

  At this time, in the eighth embodiment, the flow rate ratio (QB / QAE) is 0 when the flow rate of the additive liquid flow 388, that is, the flow rate of the additive liquid 261a is QAE, and the flow rate of the buffer liquid flow 389 is QB. The flow rate of each of the liquid streams 388 and 389 is adjusted so as to be 0.01 or more and 0.1 or less. This is because when the flow rate ratio is less than 0.01, the buffer function by the buffer layer 389a is weakened, and as described above, gelation and aggregation of additives may occur. On the other hand, if the flow rate ratio exceeds 0.1, the concentration of the additive liquid 261a in the pure dope 44 decreases, and the casting suitability of the casting dope 54 may deteriorate.

  Similarly, the other second to fourth additive liquid supply units 248 to 250 include double structure addition nozzles 51 b to 51 d and a buffer solution supply unit 385. Depending on the type of additive liquid, there are some that cause less gelation and condensation. In this case, the double-structured addition nozzle and the buffer solution supply unit may be omitted. What is necessary is just to add an additive liquid using an addition nozzle. The addition nozzles 51 and 51a used in the first to seventh embodiments are also the same as the addition nozzle 51a of this embodiment.

  As shown in FIG. 13, the in-line mixer 352 includes a split-mixing static mixer 392 and a torsion-mixing static mixer 393. The split mixing type static mixer 392 is installed in the vicinity of the front of each of the addition nozzles 51a to 51d. The split mixing type static mixer 392 is provided with elements 394 a and 394 b, which are alternately arranged in the longitudinal direction of the dope pipe 46. The elements 394a and 394b are formed by assembling a plurality of elongated partition plates so as to alternately cross each other. The split mixing type static mixer 392 mixes the pure dope 44 flowing through the dope pipe 46 and the additive liquids 261a to 261d while being divided by the elements 394a and 394b.

  The torsion mixing type static mixer 393 is arranged on the downstream side of the divided mixing type static mixer 392. The torsion mixing type static mixer 393 is provided with elements 395 a and 395 b, which are alternately arranged in the longitudinal direction of the dope pipe 46. The elements 395a and 395b are formed by twisting a rectangular plate by 180 °, and the twisting directions of the elements 395a and 395b are reversed. The elements 395a and 395b are arranged in a state of being rotated by 90 ° around the axis of the dope pipe 46 so that the side ends of the plates are orthogonal. The torsion mixing type static mixer 393 mixes the pure dope 44 flowing in the dope pipe 46 and the additive liquids 261a to 261d while being switched by the elements 395a and 395b.

  In FIG. 13, among the four addition nozzles 51 a to 51 d and the four inline mixers 352 illustrated in FIG. 10, the most upstream addition nozzle 51 a and the inline mixer 352 are illustrated, but the other addition nozzles 51 b are illustrated. The same applies to .about.51d and the in-line mixer 352 arranged downstream thereof.

  Similarly to the additive addition unit 12 of the first embodiment, the additive addition unit 312 is also provided with the second filter 53. By this second filter 53, the pure dope 44 that has passed through the in-line mixer 352 is filtered on the upstream side of the casting die 107 before being subjected to casting. As a result, the casting dope 54 in the eighth embodiment is further removed of impurities, and is sent to the casting die 107 (see FIG. 2) of the film forming unit 13.

  Also in the present embodiment, necessary additives are supplied to the pure dope 44 to which no additive is added, depending on the type of film to be manufactured, by the additive liquid supply units 247 to 250 and the addition nozzles 51a to 51d, respectively. Therefore, it is possible to respond quickly to new varieties. Further, in the present embodiment, an in-line mixer 352 is provided on each downstream side of the addition nozzles 51a to 51d, and mixing is performed each time the additive liquids 261a to 261d are supplied. The additives contained in ˜261d are each easily dispersed uniformly in the pure dope 44.

  The additive liquid blending unit 170 identifies various additives necessary for the varieties to be manufactured from the blending LUT 358a, and mixes the identified additives into the solvent 27 in a necessary amount, and blends the additive liquid.

  In the continuous production of the film 106, when changing the type and amount of various additives and switching the product type, the additive addition unit 212 switches from the old additive to the new additive while continuing the casting. . First, when the product type switching information is sent from a master controller (not shown) to the controller 358 of the additive addition unit 312, the controller 358 controls each unit so as to prepare additive liquids 261a to 261d corresponding to the new variety. . In addition, the additive liquids 261a to 261d corresponding to the old varieties are discharged, washed, and new varieties of the old varieties of additive liquids 261a to 261d so that they can be switched at this switching timing by inputting the type switching timing signal. The additive liquids 261a to 261d are circulated. Then, the three-way switching valves 266 and 267 are switched by the type switching timing signal to stop the circulation, and the on-off valve 57 is opened to add a new type of additive liquid into the pure dope from the addition nozzles 51a to 51d.

  In the present embodiment, various additive liquids 61a to 61d are added to the pure dope using the respective addition nozzles 51a to 51d provided corresponding to the respective additive liquid supply units. Although not shown, for example, an additive addition unit in which an additive liquid is added at the same position with respect to the pure dope by using one addition nozzle may be used. Also in this case, a double pipe structure is used, a mixed additive solution obtained by mixing a plurality of types of additive solutions is supplied to the inner passage, and a buffer solution is supplied to the outer passage. In addition, although not shown, instead of mixing addition, for example, a four-pipe structure, a plurality of additive liquid passages are formed, the additive liquids are individually supplied to the respective passages, and the buffer solution is supplied to the outermost layer passages. May be supplied.

  Moreover, when adding in the same position, as shown in FIG. 11, you may add an additive to a reference | standard dope (pure dope) by arrange | positioning multiple addition nozzles of the said double piping structure. A plurality of additive nozzles having a multiple piping structure may be used to add a plurality of additives at the same position or different positions in the reference dope passage.

  In the eighth embodiment, the static mixers 392 and 393 are exemplified as the inline mixer 352, but the present invention is not limited to this, and may be a dynamic mixer 420 (see FIG. 14).

  As shown in FIG. 14, the dynamic mixer 420 includes a cylindrical case 421 provided in the middle of the dope pipe 46, a mixer body 422 housed in the case 421, and a support that rotatably supports the mixer body 422. And a member 423.

  The mixer main body 422 includes a conical tip portion 422a and a cylindrical body portion 422b, and is attached to the support member 423 so that the tip portion 422a faces upstream in the liquid flow direction. Thus, a gap 425 is formed between the inner wall surface of the case 421 and the outer peripheral surface of the mixer body 422 so as to gradually decrease from the upstream side to the downstream side in the liquid flow direction. The mixer body 422 operates (rotates) on the same operating principle as that of a known pulse motor, for example, by an electromagnet provided at a predetermined pitch on the outer peripheral surface of the case 421 and a magnet built in the body portion 422b.

  The support member 423 is a substantially cylindrical rotating shaft that extends from the downstream side toward the upstream side in the liquid flow direction. The mixer body 422 is attached to the front end of the support member 423 and the rear end is fixed to the inner wall surface of the case 421. Has been. In addition, the support member 423 is formed with a gap channel 423a communicating with the dope pipe 46 on the downstream side in the liquid flow direction.

  The pure dope 44 and the additive liquids 261a to 261d sent to the dynamic mixer 420 are divided by the tip 422a of the mixer body 422, pass through the gap 425 and the gap flow path 423a, and go to the downstream dope pipe 46. Flowing. At this time, when the mixer main body 422 rotates, the pure dope 44 and the additive liquids 261a to 261d passing through the gap 425 are stirred and mixed.

  In the above embodiment, the same solution as the component of the solvent 27 of the pure dope or the reference dope in the narrow sense is used as the buffer solution 387. However, the present invention is not limited to this, and the additive solution is used as the component of the solvent. As the buffer solution 387, an additive solution diluted solution diluted with the same solution as described above, a reference dope diluted solution obtained by diluting the reference dope with the same solution as the component of the solvent, or the like may be used. The same liquid as the component is a single component when the solvent 27 is composed of a single component, and may be at least one of the plural components when the solvent 27 is composed of a plurality of components. In the above embodiment, the description has been given by taking the addition nozzle having a substantially circular cross section as an example. However, the present invention is not limited to this, and for example, it extends long in the diameter direction of the dope pipe 46. Various shaped nozzles such as a flattened nozzle may be used.

  In the fourth to eighth embodiments, the additive solution is added to the pure dope 44 immediately before the casting die 107. However, the dope is not limited to the pure dope 44. A casting dope containing various additives in the dope may be used. In this case, a film of a new variety can be produced in the same manner by adding the additive immediately before the casting die. . Various additives are mixed in the same manner when the polymer 26 and the solvent 27 are mixed in the mixing unit 15 in FIG. 5.

  Further, in place of the pure dope 44 and the conventional casting dope, when the polymer 26 and the solvent 27 are mixed in the mixing unit 15 in FIGS. 5, 7, and 10, the common additive is added and mixed together. However, it may be a reference dope in a narrow sense. The reference dope in the narrow sense is prepared by dispersing only the additive commonly required for each type when the polymer 26 and the solvent 27 are dissolved in advance. In this case, the amount of additive added immediately before the casting die, that is, the amount of additive added immediately before can be reduced by the amount of the common additive, and efficient addition becomes possible.

  In the fourth to eighth embodiments, single layer casting has been described as an example. However, similarly to the first to third embodiments, co-casting may be used.

  In addition, the static mixer 52 of the first to seventh embodiments may be either the split mixing type static mixer 392 or the torsion mixing type static mixer 393 in the eighth embodiment, or a combination thereof. . Further, the static mixer 52 may be replaced with the dynamic mixer 420.

  Examples of the present invention will be described below to specifically explain the present invention. However, the present invention is not limited to these examples.

  The following polymer 26 and solvent 27 were mixed in the dissolution tank 23 to prepare a pure dope 44. As the solvent 27, a so-called mixed solvent obtained by mixing dichloromethane, methanol, and 1-butanol was used.

[polymer]
100 parts by weight of cellulose triacetate [mixed solvent]
Dichloromethane 320 parts by weight Methanol 83 parts by weight 1-butanol 3 parts by weight

In the additive addition unit 12, the above-mentioned mixed solvent and additive were mixed to form an additive liquid A, and this additive liquid was added to the pure dope 44 by the addition nozzle 51.
[Additive liquid A]
Mixed solvent 80 parts by weight Plasticizer A 7.6 parts by weight Plasticizer B 3.8 parts by weight UV agent a 0.7 parts by weight UV agent b 0.3 parts by weight Citric acid ester mixture 0.006 parts by weight Fine particles 0.05 Parts by weight

The additive liquid B when switching film types is as follows.
[Additive liquid B]
Mixed solvent 80 parts by weight Plasticizer C 6 parts by weight Plasticizer D 6 parts by weight UV agent a 0.7 part by weight UV agent b 0.3 part by weight Citric acid ester mixture 0.006 part by weight Fine particles 0.05 part by weight

  The cellulose triacetate has a substitution degree of 2.84, a viscosity average polymerization degree of 306, a water content of 0.2% by weight, a viscosity of 6% by weight in a dichloromethane solution of 315 mPa · s, an average particle diameter of 1.5 mm, and a standard Powder with a deviation of 0.5 mm, plasticizer A is triphenyl phosphate, plasticizer B is diphenyl phosphate, UV agent a is 2 (2'-hydroxy-3 ', 5'-di- -Tert-butylphenyl) benzotriazole, UV agent b is 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, and the citrate compound is It is a mixture of citric acid, monoethyl ester, diethyl ester and triethyl ester. The fine particles have an average particle diameter of 15 nm and a Mohs hardness of about 7. It is of silicon. In addition, when preparing the pure dope 44, a retardation control agent (NN′-di-m-toluyl-Np-methoxyphenyl-1,3,5-triazine-2,4,6-triamine) is used as a film. It was added so that it might become 4.0 weight% with respect to the total weight at the time.

  Next, in the solution casting apparatus 10 shown in FIG. 1, the casting dope 54 from which the foreign matter has been removed by the second filter 53 is used, and the casting unit 13 shown in FIG. Each process of drying was performed and the TAC film 106 was obtained.

  The pipe capacity C1 of the entire process from the dissolution tank 23 to the casting die 107 inlet of the film forming unit 13 is 56000 L (liter), and the pipe capacity C2 from the addition position by the addition nozzle 51 to the casting die 107 is 8000 L. is there. After the additive liquid A was added by the addition nozzle 51, in-line mixing was performed by the static mixer 52. When switching from a film of type A using additive liquid A to pure dope 44 to a film of type B using additive liquid B to pure dope 44, the additive liquid is used without stopping continuous casting. A was switched to additive solution B. The time required for changing the varieties was 6 hours.

[Comparative Example 1]
In Comparative Example 1, instead of adding immediately before the casting die 107 in Example 1, as in the conventional equipment, the case is switched from the additive liquid A to the additive liquid B in the dissolution tank 23. The formulation for B was the same as in Example 1. The pipe capacity C1 is 56000 L, and it takes 42 hours to change from the casting dope of the product A to the casting dope of the product B. During this time, the additive liquids A and B are mixed, and the pipe capacity is about 3 Double casting dope could not be used as product, resulting in product loss.

In order to obtain the film 106 of the kind A, the dope flow rate is 20 L / min, the plasticizer addition rate is 2% immediately before, and the UV agent addition rate is 1% immediately before. The solution casting equipment 90 shown in FIG. A film 106 was manufactured in the unit 13. Before the last addition (added at the timing of C2 / C1 = 1/280) (120 minutes before), the additive liquid flow rate (400 cc / min (= 400 * 10 < ^-6 > m < ³ > / min)), and it was made to circulate and waited. Moreover, it was made to circulate and wait as an additive liquid flow rate (200 cc / min (= 200 * 10 < ^-6 > m < ³ > / min)) which made the additive liquid 99b containing UV agent the same rate as the addition ratio. In response to the addition start timing signal, switching from circulation to addition was performed, and each additive solution was added to the pure dope 44 from the addition nozzle 51. It added without generating a flow rate change after the addition operation start. In other words, by performing the standby circulation operation with the same flow rate to be added, the flow rate during the standby circulation operation and the flow rate during the addition become the same. Therefore, in the switching process from circulation to addition, only the valve moves. It becomes. For this reason, there is no occurrence of pulsation, and the additive switching time for suppressing the occurrence of pulsation becomes unnecessary. In the case of the conventional switching process, since the flow rate is adjusted after the addition start timing signal is input, the pressure also varies and the flow rate also varies. For this reason, pulsation and pressure fluctuations are large, and it takes a long time to stabilize (adjustment time), causing a loss, but this can be solved. In Example 2, pulsation prevention at the time of addition and additive adjustment time are not required, and the loss time until reaching the target addition amount that can be a product is 300 minutes, which is approximately 20% less than Example 4 described later.

In order to obtain a film 106 of type B, the dope flow rate was 20 L / min, the plasticizer addition ratio was 2%, the UV agent addition ratio was 1.1%, and the retardation control agent addition ratio was 5%. Similarly, a film 106 was produced. Before the last addition (added at the timing of C2 / C1 = 1/280) (120 minutes before), the additive liquid flow rate (400 cc / minute (= 400 * 10 < ^-6 > m < ³ > / min)), and it was made to circulate and waited. The additive liquid 65b containing the UV agent was circulated and waited at an additive liquid flow rate (220 cc / min (= 220 × 10 ⁻⁶ m ³ / min)) at the same rate as the addition ratio. Further, the additive liquid 65c containing the retardation control agent was circulated and waited at the same rate as the addition ratio as the additive liquid flow rate (1000 cc / min (= 1000 × 10 ⁻⁶ m ³ / min)). In response to the addition start timing signal, switching from circulation to addition was performed, and each additive solution was added to the pure dope 44 from the addition nozzle 51. It added without generating a flow rate change after the addition operation start. There was no need for pulsation prevention and additive adjustment time at the time of addition, and the loss time to reach the target addition amount that could be a product was 300 minutes, a decrease of about 20% compared to Example 4 described later.

In order to obtain a film of the same kind as in Example 2, the dope flow rate is 20 L / min, the plasticizer addition ratio is 2%, and the UV agent addition ratio is 1%. A film was produced by the film production unit 13 shown in FIG. C2 / C1 is 1/280. The part different from Example 2 is that the additive liquid flow rate (200 cc / min = 200 × 10 −6 m) of the addition ratio of the additive liquid 65a containing the plasticizer is added to the additive liquid 65a without circulating the additive liquid. ³ / min)) and added to pure dope 44. Moreover, the additive liquid 65b containing the UV agent was added to the pure dope 44 as an additive liquid flow rate (100 cc / min (= 100 × 10 ⁻⁶ m ³ / min)) of 1/2 of the addition ratio. In the fourth embodiment, as in the second and third embodiments, the additive liquid circulation processing is not performed immediately before switching, and the flow rate is changed after the addition start timing signal is input. Also fluctuate. For this reason, pulsation and pressure fluctuation are large, and it takes a long time (adjustment time) to stabilize. Since the dope during this adjustment time does not reach the specified additive addition ratio, it cannot be a product and causes loss. The loss time in Example 4 was 360 minutes.

In order to obtain a film of the same kind as in Example 2, the dope flow rate is 20 L / min, the plasticizer addition ratio is 2%, and the UV agent addition ratio is 1%. A film was produced by the film production unit 13 shown in FIG. Prior to the last addition (added at the timing of C2 / C1 = 1/280) (110 minutes before), the additive liquid flow rate (200 cc / min (= 200 × 10 ⁻⁶ m ³ / min) (half the flow rate of Example 2)). Further, as an additive liquid flow rate (100 cc / min (= 100 × 10 ⁻⁶ m ³ / min) (a half of the flow rate of Example 2)) in which the additive liquid 65b containing the UV agent was set to the same rate as the addition ratio, Circulated and waited. In response to the addition start timing signal, switching from circulation to addition was performed, and each additive solution was added to the dope from the addition nozzle 51. Since the circulation process is performed until just before switching at half the flow rate as compared with the first embodiment, the adjustment time can be shortened compared with the fourth embodiment, but the pulsation and pressure fluctuation are larger than those of the second embodiment. As a result, it took a little longer to adjust until it became stable, which caused loss as in Example 4. The loss time in Example 5 was 330 minutes.

  Hereinafter, Example 6 to Example 9 will be described in detail with reference to FIG. Using the solution casting apparatus 210 shown in FIG. 7, the increase addition was performed in Examples 6 to 8, and the increase addition was not performed in Example 9. In FIG. 15, the sixth embodiment is denoted by reference numeral (A), the seventh embodiment is denoted by reference numeral (B), the eighth embodiment is denoted by reference numeral (C), and the ninth embodiment is denoted by reference numeral (D). Further, “T1” shown at the bottom of the graph of FIG. 15 is a period in which the increase addition is performed, that is, a period in which the initial addition flow rate QAS is continued (hereinafter referred to as an increase addition period) (unit: minute), and “P1 "Is the time when the flow of the additive liquid 261a is switched from the initial addition flow QAS to the addition flow QAE, and" P2 "is the pressure of the additive liquid 261a at the outlet of the addition nozzle 51a. The time when the pressure equal to the pressure of the pure dope 44 near each outlet of the addition nozzle 51a, that is, the pressure increase achievement point, “T2” is a period during which the addition flow rate QAE is continued until the pressure increase achievement point (hereinafter referred to as target flow rate addition period) Means (unit; minute).

In order to obtain the film 106 of the kind B, the flow rate QD of the pure dope 44 is 5 L / min, the addition flow rate QAE is 50 cc / min (= 50 × 10 ⁻⁶ m ³ / min) at the addition ratio of 1% immediately before the additive solution. did. C2 / C1 is 1/100. In this case, the initial addition flow rate QAS was 150 cc / min (= 150 × 10 ⁻⁶ m ³ / min), and the increase addition period T1 was 15 minutes. Further, after the increase addition period T1 had elapsed, the addition flow rate QAE was set to 50 cc / min (= 50 × 10 ⁻⁶ m ³ / min), and the target flow rate addition period T2 was set to 10 minutes. The target outlet pressure of the addition nozzle 51a was 1 MPa. It took 25 minutes to increase the pressure up to 1 MPa, and the time required for the addition at the time of product changeover from product type A to product type B could be reduced by 30 minutes compared to Example 9 in which only the addition flow rate QAE described later is used. . In this example, the amount of the additive liquid 261a flowed from the start of the increase addition to P2 is 150 (cc / min) × 15 minutes + 50 (cc / min) × 10 minutes = 2750 cc (= 2750 × 10 ⁻⁶ m ³ ).

The same conditions as in Example 6 were used except that the initial addition flow rate QAS was 75 cc / min (= 75 × 10 ⁻⁶ m ³ / min), the increase addition period T1 was 30 minutes, and the target flow rate addition period T2 was 10 minutes. It took 40 minutes to increase the pressure to 1 MPA, and the time until the addition of the product from the product A to the product B was changed by 15 minutes compared to Example 9 in which only the addition flow rate QAE described later was used. . In this example, the amount of the additive liquid 261a flowed from the start of the increase addition to P2 is 75 (cc / min) × 30 minutes + 50 (cc / min) × 10 minutes = 2750 cc (= 2750 × 10 ⁻⁶ m ³ ).

The conditions were the same as in Example 6 except that the initial addition flow rate QAS was 150 cc / min (= 150 × 10 ⁻⁶ m ³ / min), the increase addition period T1 was 18 minutes, and the target flow rate addition period T2 was 1 minute. It took 19 minutes to increase the pressure to 1 MPA, and the time required for the addition at the time of product change from product type A to product type B could be reduced by 36 minutes compared to Example 9 in which only the addition flow rate QAE described later is used. . In this example, the amount of the additive liquid 261a flowed from the start of the increase addition to P2 is 150 (cc / min) × 18 min + 50 (cc / min) × 1 min = 2750 cc (= 2750 × 10 ⁻⁶ m ³ ).

Without increasing the amount, the target addition flow rate QAE was set to 50 cc / min (= 50 × 10 ⁻⁶ m ³ / min), and the liquid was fed only in the target flow rate addition period T2 to increase the pressure. Other conditions are the same as in Example 6. It took 55 minutes to increase the pressure to 1 MPA. In this example, the amount of the additive liquid 261a flowed from the start of the increase addition to P2 was 50 (cc / min) × 55 minutes = 2750 cc (= 2750 × 10 ⁻⁶ m ³ ).

  In Example 10, pure dope 44 was prepared using solution casting apparatus 310 shown in FIG. 10, using TAC as polymer 26, and using a mixed solvent of dichloromethane, methanol, and 1-butanol as organic solvent 27. The pipe capacity C1 of all processes is 56000L, and the pipe capacity C2 after the addition of the additive is 8000L. Therefore, C2 / C1 is 1/7. As an additive, a phosphate plasticizer solution ({additive weight / (additive weight + mixture solvent weight)} × 100 = 55%) is used, and the organic solvent 27 for preparing the pure dope 44 is used as the buffer solution 387. The buffer layer 389a was formed between the pure dope 44 and the additive solution. The additive liquid amount was 7% with respect to the flow rate of the pure dope 44, and the buffer solution 387 had an addition ratio of 0.07% with respect to the pure dope 44 (flow rate ratio = buffer flow rate / additive liquid amount = 0.07). /7=0.01). After the additive liquid was added, the additive liquid and the pure dope were dispersed and mixed in a composite mixer in which a dynamic mixer 420 and a torsion mixing type static mixer 393 were connected in series. Gelation did not occur, and casting and stripping could be performed without problems.

  The conditions were the same as in Example 10 except that the addition ratio of the buffer solution 387 was 0.7% (flow rate ratio = 0.7 / 7 = 0.1). Gelation did not occur, and casting and stripping could be performed without problems.

  The conditions were the same as in Example 10 except that the addition ratio of the buffer solution 387 was 0.06% (flow rate ratio = 0.06 / 7≈0.009). Gelation occurred.

  The conditions were the same as in Example 10 except that the addition ratio of the buffer solution 387 was 0.8% (flow rate ratio = 0.8 / 7≈0.11). Although gelation did not occur, the gel strength was lowered due to a decrease in the concentration of the casting dope, and therefore, unpeeled residue was generated at the time of peeling.

10, 90, 210, 310 Solution casting apparatus 11 Pure dope preparation unit 12, 82, 92, 187, 212, 312 Additive addition unit 13 Film forming unit 15, 85 Mixing part 16 Dissolving part 17 Concentrating part 18 Reserving part 26 Polymer 27 Solvent 44 Pure dope 50, 93 Additive supply unit 51, 51a to 51d Addition nozzle 52 Static mixer 54 Casting dope 81 Standard dope 83 Common additive 93 Additive supply unit 170 Additive liquid preparation unit 173, 265 Circulation unit 182,270 Cleaning liquid supply unit 247-250 First to fourth additive liquid supply units

Claims (21)

A reference dope preparation step for preparing a reference dope comprising a polymer and a solvent;
When the pipe capacity from the reference dope preparation step to the casting die is C1, the piping of {(1/280) × C1} or more and {(1/7) × C1} or less on the basis of the casting die upstream position where the capacitance, and the adding step to the specific additives and added pressure teeth casting dope to each model relative to the reference dope,
A casting step of casting the casting dope onto a support by the casting die, and forming a casting film on the support;
A stripping step of imparting self-supporting property to the casting membrane and peeling the casting membrane from the support as a wet film;
A drying step of drying the wet film to form a film;
When changing the type of film, the additive changing step of changing the additive in the addition step according to the type,
The addition step includes an additive solution preparation step of preparing an additive solution by adding the additive into the solution, and adding the additive solution with an addition nozzle,
In the additive changing step, the additive flow rate ratio {(QAE / QD) × 100} of the additive flow rate QAE of the additive solution added in accordance with a new variety is 10% or less with respect to the flow rate QD of the reference dope. When the addition flow rate QAE of the additive liquid is 300 × 10 ⁻⁶ m ³ / min or less, the addition amount is increased for a certain time at an initial addition flow rate of 1.5 to 3.0 times the addition flow rate QAE. And performing the addition flow rate QAE after the lapse of the predetermined time.   The said predetermined time is a time until the pressure of the said additive liquid in the exit of the said addition nozzle becomes the same as the pressure of the said reference | standard dope in the exit vicinity of the said addition nozzle, It is characterized by the above-mentioned. Solution casting method. A circulation step of circulating the additive solution in advance before adding to the reference dope;
3. The solution casting method according to claim 1, wherein the additive solution is circulated at the initial addition flow rate in the circulation step. A reference dope preparation step for preparing a reference dope comprising a polymer and a solvent;
When the pipe capacity from the reference dope preparation step to the casting die is C1, the piping of {(1/280) × C1} or more and {(1/7) × C1} or less on the basis of the casting die upstream position where the capacitance, and the adding step to the specific additives and added pressure teeth casting dope to each model relative to the reference dope,
A casting step of casting the casting dope onto a support by the casting die, and forming a casting film on the support;
A stripping step of imparting self-supporting property to the casting membrane and peeling the casting membrane from the support as a wet film;
A drying step of drying the wet film to form a film;
When changing the type of film, the additive changing step of changing the additive in the addition step according to the type,
The addition step includes an additive solution preparation step of preparing an additive solution by adding the additive into the solution, and adding the additive solution with an addition nozzle,
The adding step has a mixing step of mixing and standardizing the reference dope to which an additive solution has been added to make the casting dope,
A solution casting method, wherein a buffer layer is formed on the outer periphery of the additive solution and added to the reference dope.   The buffer solution is the same solution as the solvent component, the additive solution diluted with the same solution as the solvent component, and the reference dope dilution obtained by diluting the reference dope with the same solution as the solvent component. 5. The solution casting method according to claim 4, wherein the solution is any one of liquids.   In the addition step, the flow rate ratio (QB / QAE) is 0.01 or more when the buffer solution is the same solution as the solvent component, the flow rate of the additive solution is QAE, and the flow rate of the buffer solution is QB. 6. The solution casting method according to claim 5, wherein the solution is made 0.1 or less.   The solution casting method according to claim 4, wherein the mixing step is performed by passing through a plurality of in-line mixers having different mixing methods.   The in-line mixer is formed by alternately intersecting a torsion-mixing static mixer configured by arranging a plurality of first elements each composed of a twisted partition member in the reference dope passage and a plurality of elongated partition members. At least one of a split-mix type through-the-mixer configured by arranging a plurality of second elements in the reference dope passage and a dynamic mixer configured by arranging a rotating mixer body in the reference dope passage 8. The solution casting method according to claim 7, wherein the solution casting method is one. Solution casting method according to any one of claims 1 to 8, wherein the ratio of the flow rate of the additive liquid to the flow rate of the reference dope is 30% or less than 1% in the addition step. The addition step solution casting method according to any one of claims 1 to 9, characterized by the addition of the additive solution in-line. The additive includes a plasticizer,
Solution casting method according to any one of claims 1 to 10, wherein the concentration of the plasticizer in the additive liquid is 10 wt% or more 65 wt% or less. The solution casting method according to any one of claims 1 to 11 , wherein the reference dope includes an additive commonly required for each type. The solution casting method according to any one of claims 1 to 12 , wherein the reference dope is a pure dope including the polymer and the solvent. Wherein prior to adding the reference dope, solution casting method according to any one of claims 1 to 13, characterized in that it has a circulation process allowed to advance circulating said additive liquid. The solution casting method according to claim 14 , wherein in the circulation step, the additive solution is circulated at the same flow rate as the flow rate when the additive solution is added to the reference dope. 16. The solution casting method according to claim 14 , wherein the circulation step is started 120 minutes or more before the start of the addition. When switching the type of the film, before adding the additive liquid used for a new type, the cleaning of the flow path of the additive liquid to the addition nozzle with a cleaning liquid made of the same liquid as the solvent component The solution casting method according to claim 14 , further comprising a step. A reference dope preparation unit for preparing a reference dope comprising a polymer and a solvent;
When the pipe capacity from the preparation of the reference dope to the casting die is C1, {(1/280) × C1} or more and {(1/7) × C1} or less based on the casting die in the pipe volume to become the upstream side position, and additives added unit to the specific additives and added pressure teeth casting dope to each model relative to the reference dope,
The casting dope to which the additive is added is cast on a support by the casting die to form a casting film on the support, and the casting film is provided with a self-supporting property. A casting unit that peels off the cast film as a wet film from the support, and obtains a film by drying the wet film; and
When changing the type of film, an additive change unit for changing the additive to be added to the reference dope into a new prescription,
The additive addition unit is
An addition nozzle for adding an additive liquid containing the additive to the liquid to the reference dope;
An additive supply unit for preparing the additive liquid to be supplied to the addition nozzle;
A mixing part that mixes and homogenizes the reference dope to which the additive solution has been added to form a casting dope,
The solution forming apparatus, wherein the addition nozzle has a buffer solution layer forming means for forming a buffer solution layer on the outer periphery of the additive solution. 19. The solution casting apparatus according to claim 18 , wherein the additive supply unit has an additive circulation means for circulating the additive liquid upstream of the addition nozzle. The additive addition unit includes a cleaning unit that cleans the flow path of the additive liquid to the addition nozzle with a cleaning liquid composed of the same liquid as the solvent component when the film type is switched. 20. The solution casting apparatus according to claim 18 or 19 . 21. The solution casting apparatus according to claim 18 , wherein the additive supply unit includes a flow rate control unit that controls a flow rate of the additive solution.

Images