JP2009214312A - Casting device, solution film forming equipment, and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a pressure change in a decompression chamber interior by suppressing flowing-in of the inflow wind into the decompression chamber. <P>SOLUTION: In a casting device, a dope discharged from a casting die forms a casting film on the peripheral surface traveling in the X direction after forming a casting bead. The decompression chamber depressurizes the upstream side of the X direction of the casting bead by sucking. The decompression chamber has a pair of side labyrinth plate 76 and a width labyrinth plate 77. The pair of side labyrinth plate 76 is provided in the X direction. The width labyrinth plate 77 bridges the pair of side labyrinth plates 76 and provided in Y direction. The side labyrinth plate 76 is provided with a labyrinth groove 96 extending in X direction. Both the ends of the X direction of the labyrinth groove 96 are provided with wind shielding members 98 so as to block the labyrinth groove 96. The wind labyrinth plate 77 is provided with the labyrinth groove 97 extending in the Y direction. Both the ends parts in the Y direction of the width labyrinth plate 77 abut to the pair of side labyrinth plate 76 so as to block the labyrinth groove 96. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a casting apparatus, a solution casting apparatus, and a solution casting method.

  Polymer films (hereinafter referred to as “films”) are widely used as optical functional films because of their features such as excellent light transmittance, flexibility, and light weight thinning. Among them, cellulose ester films using cellulose acylate have toughness and low birefringence, and therefore, the composition of liquid crystal display devices (LCDs) that have recently expanded in the market including photographic photosensitive films. It is used as a protective film or an optical compensation film for a polarizing plate as a member.

  Main film production methods include a melt extrusion method and a solution casting method. The melt extrusion method is a method in which a polymer is heated and dissolved as it is, and then extruded with an extruder to produce a film, which has features such as high productivity and relatively low equipment cost. However, it is difficult to adjust the film thickness with high precision, and since fine lines (die lines) can be formed on the surface of the film, a high quality film that can be used for an optical functional film is manufactured. Is difficult. On the other hand, in the solution casting method, a cast film formed by casting a polymer solution containing a polymer and a solvent on a support has self-supporting properties, and then peeled off from the support. In this method, a wet film is formed, and the wet film is further dried to form a film. Compared with the melt extrusion method, it is superior in optical isotropy and thickness uniformity, and can obtain a film with less contained foreign substances. Therefore, optical functional films for LCD applications are mainly produced by a solution casting method. ing.

  This solution casting method prepares a polymer solution (hereinafter referred to as a dope) in which a polymer such as cellulose triacetate is dissolved in a mixed solvent containing dichloromethane or methyl acetate as a main solvent. Furthermore, a predetermined additive is mixed with this dope to prepare a casting dope. Using a casting die, a casting dope is cast on a support such as a casting drum or an endless band to form a casting film (hereinafter referred to as a casting step). After the cast film is cooled on the support and becomes self-supporting, it is peeled off from the support as a film (hereinafter referred to as a wet film), and the wet film is dried as a film. Wind up.

  By the way, in order to meet the recent significant increase in demand for liquid crystal display devices and the like, establishment of a solution film forming method with high production efficiency is required. Considering from the viewpoint of improving the production efficiency, the casting process becomes rate-determining when the speed of the solution casting method is increased. In order to increase the speed of the solution casting method, the traveling speed of the support is increased, and a decompression means such as a decompression chamber is provided on the back side of the casting bead formed by casting dope from the casting die to the support. It is also used to reduce the pressure.

In the casting process, if the gap between the support and the decompression chamber fluctuates, the pressure in the decompression chamber fluctuates, the dope landing point fluctuates, and the film thickness of the casting film is uneven. The adhesion between the support surface and the casting bead is lowered, and air may be mixed between the casting membrane and the support surface. And when these generate | occur | produced, the film thickness nonuniformity and the film surface defect (a stripe, a step nonuniformity, etc.) generate | occur | produced and became a problem. For this reason, in Patent Document 1, when the gap between the support and the decompression chamber is detected and becomes a set value or less, the decompression chamber is moved so that the gap between the support and the decompression chamber becomes greater than the set value. An apparatus for producing such a film has been proposed. Patent Document 2 proposes a cellulose ester film manufacturing apparatus using a decompression chamber having a plurality of labyrinth seals.
JP 2001-79864 A JP 2003-1655 A

  However, even when solution film formation is performed using the above-described decompression chamber, fluctuations in pressure in the decompression chamber cannot be sufficiently suppressed. As a result of intensive studies, the inventor has found that the pressure fluctuation in the decompression chamber is caused by the structure of the labyrinth seal.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a casting apparatus, a solution casting apparatus, and a solution casting method that can easily suppress the pressure fluctuation inside the decompression chamber. And

  The present invention discharges a dope from a casting die to a traveling support, forms a casting bead from the casting die to the support, forms a casting film on the support, In the casting apparatus for decompressing the upstream side in the running direction of the support of the casting bead by the suction used, the casting bead is provided in the decompression chamber between the decompression chamber and the support, and is orthogonal to the inflow air by the suction. And at least one pair of protrusions for forming a labyrinth groove extending in a long direction, and a shielding member provided at both ends in the longitudinal direction of the labyrinth groove and blocking the suction air by closing the labyrinth groove. It is characterized by providing. Moreover, it is preferable that the labyrinth groove extends long in the running direction of the support.

  Further, the solution casting apparatus of the present invention comprises the above casting apparatus, a stripping apparatus for stripping the casting film from the support, and drying the stripped casting film to form a film. And a device.

  Furthermore, the solution casting method of the present invention is characterized in that the casting film is formed on the support using the casting apparatus, and the casting film is peeled off and dried to form a film. .

  According to the casting apparatus of the present invention, at least one pair of protrusions for forming a labyrinth groove that is provided in the decompression chamber between the decompression chamber and the support and extends long in a direction perpendicular to the inflow air by suction. Since the shield member is provided at both ends of the labyrinth groove in the longitudinal direction and blocks the labyrinth groove and suppresses inflow of suction air, the inflow of inflow air to both ends of the labyrinth groove can be prevented. Therefore, according to the present invention, since the inflow of the inflow air into the decompression chamber can be suppressed, the pressure fluctuation in the decompression chamber can be suppressed, and as a result, the film can be manufactured while suppressing the occurrence of thickness unevenness. it can.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments listed here.

  As shown in FIG. 1, the film production line 10 includes a stock tank 11, a casting chamber 12, a pin tenter 13, a clip tenter 14, a drying chamber 15, a cooling chamber 16, and a winding chamber 17.

  The stock tank 11 is provided with a stirring blade 11b rotated by a motor 11a and a jacket 11c, and a casting dope (hereinafter referred to as dope) 21 as a raw material for the film 20 is stored therein. . In the stock tank 11, the temperature of the dope 21 is adjusted to 25 to 35 ° C. by flowing a heat transfer medium inside the jacket 11c, and the stirring blade 11b is rotated by the motor 11a. Thereby, the dope 21 is kept homogeneous while suppressing aggregation of polymers and the like.

  A pump 25 and a filtration device 26 are provided downstream of the stock tank 11. An appropriate amount of the dope 21 is appropriately sent from the stock tank 11 to the filtering device 26 by the pump 25 and filtered to remove impurities in the dope 21.

  In the casting chamber 12, as a casting apparatus, a casting die 30 that is an outflow means of the dope 21, a casting drum 32 that is an endless support, and a peeling film 33 that peels off the casting film 33 from the casting drum 32. A roller 34, a temperature adjusting device 35 for adjusting the internal temperature of the casting chamber 12, and a decompression chamber 36 as decompression means are provided.

  As shown in FIG. 2, an outlet 30 a through which the dope 21 flows out is provided at the tip of the casting die 30. The outflow port 30a casts the dope 21 on the peripheral surface 32a of the casting drum 32 disposed below the outlet 30a. The material of the casting die 30 is formed of a material having high corrosion resistance against a mixed solution of an electrolyte aqueous solution, methylene chloride, methanol, and the like, and a low coefficient of thermal expansion. Moreover, it is preferable to use the finishing precision of the wetted surface of the casting die 30 with a surface roughness of 1 μm or less and a straightness of 1 μm / m or less in any direction. By using such a casting die 30, a casting film 33 without streaks and unevenness can be formed on the casting drum 32.

  As shown in FIGS. 1 and 2, the casting drum 32 is formed in a substantially cylindrical shape, and is rotated around an axis by a driving device (not shown). With this driving device, the casting drum 32 rotates so that the peripheral surface 32a travels in a predetermined traveling direction (hereinafter referred to as X direction) at a predetermined traveling speed (10 to 300 m / min). The peripheral surface 32a of the casting drum 32 is subjected to a chrome plating process and has sufficient corrosion resistance and strength. A heat transfer medium circulation device 37 is attached to the casting drum 32. The heat transfer medium maintained at a desired temperature in the heat transfer medium circulation device 37 passes through the heat transfer medium flow path in the casting drum 32, so that the surface temperature of the casting drum 32 is in a desired range. Can be held in.

  In the casting process, the dope 21 flows out from the outlet 30 a toward the peripheral surface 32 a of the casting drum 32. The dope 21 forms a casting bead 40 from the outlet 30a to the peripheral surface 32a. On the traveling peripheral surface 32a, the dope 21 is flowed and a cast film 33 is formed. The casting film 33 is conveyed at a predetermined speed in the X direction by the rotation of the casting drum 32. In this way, by continuously flowing out the dope 21 to the traveling peripheral surface 32a, the elongated casting film 33 is formed on the peripheral surface 32a.

  The decompression chamber 36 is disposed on the upstream side in the X direction with respect to the casting die 30 and decompresses the back side of the casting bead 40 with a negative pressure. By reducing the pressure on the back side of the casting bead 40, the adhesion between the circumferential surface 32a and the casting bead 40 is improved, so that air is mixed between the casting film 33 and the circumferential surface 32a. Can be prevented. Here, the back side refers to one side of the casting bead 40 located on the upstream side in the X direction. As shown in FIG. 1, the decompression chamber 36 is connected to a suction device 46 via a pipe 45. As shown in FIG. 2, the control unit (not shown) depressurizes the hollow portion 60 a of the decompression chamber 36 via the suction device 46, and as a result, the back side of the casting bead 40 is set within a range of −1500 Pa to −10 Pa. The pressure can be reduced. As shown in FIG. 1, the casting film 33 provided with self-supporting property by cooling on the casting drum 32 is peeled off from the casting drum 32 by the peeling roller 34 to become a wet film 47.

  The internal temperature of the casting chamber 12 is adjusted by the temperature control equipment 35 so as to be substantially constant within a predetermined range. The internal temperature of the casting chamber 12 is preferably 10 ° C or higher and 30 ° C or lower. In the casting chamber 12, a condenser (condenser) 48 for condensing and recovering the vaporized solvent and a recovery device 49 for recovering the condensed and liquefied solvent are provided. The organic solvent condensed and liquefied by the condenser 48 is recovered by the recovery device 49. The solvent is regenerated as a solvent for preparing a dope after being regenerated by a regenerator. By this recovery device 49, the condensation point of the solvent in the casting chamber 12 is maintained at -10 ° C or higher and 25 ° C or lower. When the condensation point in the casting chamber 12 is less than −10 ° C., the solvent is likely to evaporate, which is not preferable because the plate-out easily occurs. When the condensation point exceeds 25 ° C., the film surface is not preferable. It is not preferable because the condensation of the solvent that causes the failure of the state tends to occur on the peripheral surface 32a. Here, the condensation point is a temperature at which condensation of the solvent contained in the atmosphere starts.

  A pin tenter 13 that dries the wet film 47 to form the film 20 and a clip tenter 14 that stretches while drying the film 20 are provided downstream of the casting chamber 12. In the pin tenter 13, a large number of pins are inserted and fixed at both end portions of the wet film 47, and then drying is promoted while the wet film 47 is conveyed to form the film 20. Then, the film 20 still containing the solvent is fed into the clip tenter 14.

  In the clip tenter 14, drying is promoted while the film 20 is transported after the both ends of the film 20 are sandwiched by a number of clips that run endlessly by the movement of the chain. At this time, the film 20 is stretched by expanding the width of the facing clip and applying tension in the width direction of the film 20. Thus, by the stretching process in the width direction of the film 20, the molecules in the film 20 are oriented, and desired optical properties such as retardation can be imparted to the film 20. The clip tenter 14 may be omitted.

  The film 20 sent out from the clip tenter 14 is cut at both end portions by the edge-cutting device 51. The edge-cutting device 51 is provided with a crusher 52. Here, both end portions of the film 20 are cut and then fed into the crusher 52 to be crushed. The crushed film strip is reused as a raw material dope.

  The film 20 whose both end portions are cut by the edge cutting device 51 is sent to the drying chamber 15. The drying chamber 15 is provided with a number of rollers 53 and an adsorption / recovery device 54. The film 20 is conveyed through the drying chamber 15 by a roller 53. The film 20 dried in the drying chamber 15 is sent to the cooling chamber 16, cooled to 30 ° C. or less, and then sent to the winding chamber 17. Further, a forced static elimination device (static elimination bar) 55 is provided downstream of the cooling chamber 16. Furthermore, in the present embodiment, a knurling roller 56 is provided on the downstream side of the forced static elimination device 55.

  Inside the winding chamber 17, there are provided a winder 57 and a press roller 58 that rotate the core 57 a to wind the film 20 around the core 57 a. The film 20 sent to the winding chamber 17 is wound around the winding core 57 a while being pressed by the press roller 58.

  As shown in FIGS. 2 and 3, the decompression chamber 36 includes a casing 60. The casing 60 has a hollow interior from a pair of side plates 61 provided in the X direction, a top plate 62 spanned between the side plates 61, first to second front plates 63 to 64, and a rear plate 66. It forms so that it may become the part 60a. An opening 60 b that is partially blocked by the tip 30 c of the casting die 30 is formed on the front side of the casing 60, and the casing 60 is disposed near the peripheral surface 32 a of the casting drum 32. The opening 60c to be formed is formed. As a forming material of each plate 61-66, it is preferable that it has the intensity | strength which is hard to melt | dissolve in an organic solvent and can endure the pressure difference with the inside of the casing 60, and the exterior, for example, each plate 61-66 is stainless steel. Composed.

  As shown in FIGS. 3 and 4, a pair of ear side seal plates 71, an inner side seal plate 72, and an inner width seal plate 73 are provided in the casing 60. The ear side seal plate 71 and the inner side seal plate 72 are provided in the X direction, and the hollow portion 60a is divided into a plurality of portions in the width direction of the casting film 33 (hereinafter referred to as the Y direction). Each of these side seal plates 71, 72 acts as a rectifying plate for the incoming air 400 by suction of the decompression chamber 36. The inner width seal plate 73 is provided in the Y direction and is fixed to the inner side seal plate 72. Further, the inner width seal plate 73 is attached to and held by the casing 60.

  The ear side seal plate 71 is provided on the upstream side in the X direction of the both end portions 40 a of the casting bead 40. Here, the both end portions 40a indicate both end portions of the casting bead 40 in the Y direction. The hollow portion 60a is divided into three compartments in the Y direction by a pair of ear side seal plates 71: a both-end chamber portion and a central chamber portion. Each of the seal plates 71 to 73 is preferably formed of a material that is difficult to dissolve in an organic solvent such as MC nylon (registered trademark) or Teflon (registered trademark).

  A pair of side labyrinth plates 76 and a width labyrinth plate 77 are provided outside the casing 60. The pair of side labyrinth plates 76 is provided along the side plate 61, and the width labyrinth plate 77 is provided along the rear plate 66. Each labyrinth plate 76, 77 is provided with a labyrinth groove which will be described later. The labyrinth groove can prevent the inflow air 400 from flowing into the hollow portion 60a. Note that the side labyrinth plate 76 and the width labyrinth plate 77 may be omitted. In this case, a labyrinth groove may be formed directly on the lower end surfaces of the side plate 61 and the rear plate 66 constituting the casing 60.

  As shown in FIG. 5, the width labyrinth plate 77 includes a plurality of seal plates 83 that overlap in the X direction. The width labyrinth plate 77 is attached to the end portion 66 a on the peripheral surface 32 a side of the rear plate 66 by the bracket 84. The seal plate 83 is preferably formed from a material that is difficult to dissolve in an organic solvent, such as MC nylon (registered trademark) or Teflon (registered trademark).

  Each seal plate 83 is provided in the Y direction, and is arranged so as to stand up with respect to the peripheral surface 32a and so that the end portion 83a of each seal plate 83 is close to the peripheral surface 32a. A groove forming recess 86 is provided at the end 83a so as to extend in the Y direction.

The groove forming recess 86 includes a bottom surface 86a, a slope 86b, a tip 86c, and a vertical surface 86d that are provided in order from the downstream side in the X direction toward the upstream side. The clearance between the bottom surface 86a and the peripheral surface 32a is substantially constant in the X direction, and the clearance between the inclined surface 86b and the peripheral surface 32a gradually decreases from the downstream side in the X direction toward the upstream side. Due to the inclined surface 86b and the vertical surface 86d, the cross-sectional shape of the tip 86c on the surface orthogonal to the X direction is formed at an acute angle. The tip angle θ1 of the tip 86c in this cross section is preferably 20 ° or more and 60 ° or less, and more preferably 30 ° or more and 50 ° or less. Further, the cross-sectional area of the groove forming recess 86 on the surface orthogonal to the Y direction is preferably 300 mm ² or more and 2000 mm ² or less, and more preferably 700 mm ² or more and 1500 mm ² or less.

  As shown in FIG. 5 and FIG. 6, by overlapping the seal plates 83 each having such a groove forming recess 86 at the end 83 a in the X direction, the end on the peripheral surface 32 a side of the width labyrinth plate 77 is formed. , A labyrinth groove 97 extending in the Y direction is formed. Similarly, the side labyrinth plate 76 includes five seal plates 83 that overlap in the Y direction, and is attached to the end portion of the side plate 61 on the peripheral surface 32a side. Thus, a labyrinth groove 96 extending in the X direction is formed at the end of the side labyrinth plate 76 on the peripheral surface 32a side.

  As shown in FIGS. 4 and 7, both end portions of the width labyrinth plate 77 in the Y direction are in contact with the pair of side labyrinth plates 76. Thus, the pair of side labyrinth plates 76 closes both ends of the labyrinth groove 97 in the Y direction. As shown in FIGS. 6 and 7, a wind shielding member 98 is provided at the upstream end of the labyrinth groove 96 in the X direction. Although not shown in the figure, a wind shielding member 98 is also provided at the downstream end of the labyrinth groove 96 in the X direction. Thus, the wind shielding member 98 closes both ends of the labyrinth groove 96 in the X direction. Note that a plurality of wind shielding members 98 may be arranged in the labyrinth groove 98 to block both ends in the Y direction of all the labyrinth grooves 97.

  Next, the operation of the film production line 10 configured as described above will be described. As shown in FIGS. 1 and 2, the casting drum 32 rotates and the peripheral surface 32a travels in the X direction. When the dope 21 flows out from the outlet 30a toward the peripheral surface 32a, a casting bead 40 is formed from the outlet 30a to the peripheral surface 32a. By a control unit (not shown), the suction device 46 sucks the air in the hollow portion 60a of the decompression chamber 36 and depressurizes the hollow portion 60a to a desired pressure.

  As shown in FIG. 4, the air on the back surface side of the casting bead 40 and the air outside the casing 60 flow toward the hollow portion 60 a as inflow air 400 by this suction. The side labyrinth plate 76 prevents inflow of the inflow air 400 from the side, and the width labyrinth plate 77 prevents inflow of the inflow air 400 from the upstream side in the X direction.

  As shown in FIGS. 4 and 7, the pair of side labyrinth plates 76 block both ends in the Y direction of the labyrinth groove 97, so that the inflow of the inflow air 400 into the labyrinth groove 97 can be suppressed. Similarly, as shown in FIG. 7, since the wind shielding member 98 closes both ends of the labyrinth groove 96 in the X direction, the inflow of the incoming air 400 into the labyrinth groove 96 can be suppressed. Thus, since the inflow of the inflow air 400 into the labyrinth grooves 96 and 97 can be suppressed, the casting process can be performed while suppressing the pressure fluctuation of the hollow portion 60a that causes the thickness unevenness. Therefore, according to the present invention, a film can be produced while suppressing thickness unevenness.

  The wind shield member 98 may be formed integrally with the side labyrinth plate 76. Further, the wind shield member is not limited to the wind shield member 98 described above as long as the cross section of the labyrinth groove can be closed. For example, as shown in FIG. 8, wind shielding members 99 are provided at both ends in the Y direction of the labyrinth groove 97, and the slope 99 b, the tip 99 c and the vertical surface 99 d are attached to the wind shielding member 99 in the Y direction of the labyrinth groove 97. You may form sequentially from the center part toward both ends. The inclined surface 99b and the vertical surface 99d are preferably formed in the same shape as the inclined surface 86b and the vertical surface 86d, and the tip 99c is preferably formed with an acute angle in cross section, similar to the tip 86c. In the labyrinth groove 97, a plurality of wind shielding members 99 may be arranged in the direction Y.

  In the above-described embodiment, the pair of side labyrinth plates 76 are provided so as to abut on both ends of the width labyrinth plate 77 in the Y direction so as to block both ends of the labyrinth groove 97 in the Y direction. However, the width labyrinth plate 77 may be provided in contact with the upstream end portion in the X direction of the side labyrinth plate 76 so as to block the upstream end portion in the X direction of the labyrinth groove 96. And the wind shield member 98 and the wind shield member 99 may be provided at both ends in the Y direction of the labyrinth groove 97 and downstream ends of the labyrinth groove 96 in the X direction.

  In the above-described embodiment, the labyrinth grooves 96 and 97 having a sharp tip 86c are provided, but the present invention is not limited to this, and the cross-sectional shape of the tip 86c may be an obtuse angle or an arc. The labyrinth grooves 96 and 97 may be V-grooves, U-grooves or square grooves, or may have a rectangular or arcuate cross-sectional shape.

  In the above embodiment, the labyrinth grooves are provided in the labyrinth plates 76 and 77 by superimposing the plurality of seal plates 83. However, the present invention is not limited to this, and the circumference of the labyrinth plates 76 and 77 is not limited thereto. A labyrinth groove may be provided at the end on the surface 32a side.

  Further, similarly to the labyrinth plates 76 and 77, it is preferable that a labyrinth groove is provided at the end portion of each seal 71 to 73 on the peripheral surface 32a side. And it is preferable to provide a wind-shielding member in the both ends of the direction where these labyrinth grooves extend long. Thereby, it becomes possible to improve the rectification effect in the vicinity of the ear | edge part of the casting bead 40, and the vibration of the casting bead 40 can be suppressed.

  As the width of the film 22 to be manufactured increases, the width of the casting film increases, and as a result, pressure fluctuations in the hollow portion 60a of the decompression chamber 36 tend to occur. According to the casting apparatus of the present invention, it is possible to suppress the pressure fluctuation in the hollow portion 60a of the decompression chamber 36 even when the width is widened. For example, the width of the cast film is preferably 600 mm or more, and more preferably 1400 mm or more and 3000 mm or less. The present invention is also effective when it is larger than 3000 mm.

  Furthermore, when casting dopes, simultaneous lamination co-casting in which two or more types of dopes are simultaneously co-cast and laminated, or sequential lamination co-casting in which multiple dopes are sequentially co-cast and laminated It can be performed. In addition, you may combine both casting. When performing simultaneous lamination and co-casting, a casting die to which a feed block is attached may be used, or a multi-manifold casting die may be used. However, it is preferable that at least one of the thickness of the layer on the air surface side and the thickness of the layer on the support side is 0.5 to 30% of the thickness of the entire film of the film composed of multiple layers by co-casting. . In addition, when performing simultaneous lamination and co-casting, it is preferable that the high-viscosity dope is enveloped by the low-viscosity dope when the dope is cast from the die slit to the support, and is formed from the die slit to the support. Of the casting beads, the dope in contact with the outside world preferably has a higher alcohol composition ratio than the inner dope.

  The present invention can also be applied to a casting apparatus that uses a casting band that moves over a rotating roller instead of the casting drum 32.

It is explanatory drawing which shows the outline | summary of a film manufacturing line. It is a side view which shows the outline | summary of a casting die, a casting drum, and a pressure reduction chamber. It is a perspective view which shows the outline | summary of a casting drum and a pressure reduction chamber. It is a top view which shows the outline | summary of the pressure reduction chamber when it sees from the surrounding surface side of a casting drum. It is a VV line sectional view showing an outline of a width labyrinth board and its peripheral member. It is a top view when the outline | summary of the contact part of a width labyrinth board and a side labyrinth board is seen from the surrounding surface side of a casting drum. It is a perspective view which shows the outline | summary of a labyrinth groove | channel and the wind-shielding member provided in the labyrinth groove | channel. It is a perspective view which shows the outline | summary of a 2nd wind shielding member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Film production line 12 Casting chamber 20 Film 21 Dope 21a Casting bead 30 Casting die 32 Casting drum 32a Circumferential surface 33 Casting film 36 Decompression chamber 60 Casing 60b, 60c Opening 71 Ear side seal plate 72 Inner side seal Plate 73 Inner width seal plate 76 Side labyrinth plate 77 Width labyrinth plate 83 Seal plate 86 Groove forming recess 86a Bottom surface 86b Slope 86c Tip 86d Vertical surface 96, 97 Labyrinth groove 98, 99 Wind shield member

Claims (4)

A dope is discharged from a casting die onto a traveling support, and after forming a casting bead from the casting die to the support, a casting film is formed on the support, and suction is performed using a vacuum chamber. In the casting apparatus for decompressing the traveling direction upstream side of the support of the casting bead,
At least one pair of ridges provided in the decompression chamber between the decompression chamber and the support and for forming a labyrinth groove extending in a direction orthogonal to the inflow air by the suction;
A casting apparatus comprising: a shielding member provided at both ends in the longitudinal direction of the labyrinth groove and blocking the inflow of the suction air by closing the labyrinth groove.   The casting apparatus according to claim 1, wherein the labyrinth groove extends long in the traveling direction of the support. The casting apparatus according to claim 1 or 2,
A stripping device for stripping the cast film from the support;
A drying device for drying the cast film peeled off to form a film;
A solution casting apparatus comprising:   A solution casting method, wherein the casting film is formed on the support using the casting apparatus according to claim 1, and the casting film is peeled off and dried to form a film.

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