TW201534451A - Labyrinth seal, casting device, and solution casting apparatus and method - Google Patents

Abstract

There are provided a labyrinth seal, a casting device, a solution casting apparatus, and a solution casting method, for preventing occurrence of streak unevenness and air entrainment at the time of producing a thin film at a high speed. An air shielding block is disposed in proximity to a belt along a bead at an upstream side in a moving direction of the belt, so as to prevent accompanied air from blowing toward the bead. A labyrinth seal is formed on a surface of the air shielding block facing the belt. The labyrinth seal consists of first to third seal sections. The first to third seal sections include seal units composed of three teeth and grooves. A height and a width of each of the grooves are determined in accordance with frequency band of air pressure vibration of the accompanied air. Each of the grooves prevents vibration of the bead, and thereby streak unevenness does not occur on a casting film.

Description

Labyrinth seal, casting device, solution film forming device and method

The present invention relates to a labyrinth seal, a casting device, a solution film forming apparatus and method.

A translucent polymer film (hereinafter referred to as a film) is widely used as an optical film such as a protective film of a polarizing plate, a retardation film, an antireflection film, or a transparent conductive film. The uniformity and optical properties of the thickness are required for the film. Conventionally, a thick film having a thickness of 80 μm or more has been mainly used. However, in recent years, a thin film forming demand for a film has been increased, and a thin film having a thickness of 40 μm or less has been required.

As a method for producing a film, there is a solution film forming method. The solution film forming method is a method of obtaining a film by, for example, casting a casting support (hereinafter referred to as a support) such as a metal drum or a conveyor belt by a casting die (hereinafter referred to as a die). A cast film in which a polymer is dissolved in a solvent (hereinafter referred to as a dope) is formed to form a cast film, which is dried and stripped.

In order to increase the productivity of the solution film formation, it is a problem to increase the speed of the casting process in which the cast film is formed from the dope. In order to carry out the casting process at a high speed, for example, when the traveling speed of the support body is increased, a wind that flows in the traveling direction together with the support body as the support body travels is generated in the vicinity of the surface of the support body (hereinafter, referred to as carrying wind) ). If the carrying wind blows onto the liquid bead, the liquid bead vibrates. The vibration of the bead causes uneven thickness in the casting direction of the produced film (the traveling direction of the support). For this reason, for example, in Japanese Laid-Open Patent Publication No. 2004-114328, a windshield is disposed close to the liquid bead on the upstream side of the support in the traveling direction of the support, thereby preventing the carrier air from entering the liquid bead.

Further, in Japanese Laid-Open Patent Publication No. 2010-158834, a decompression chamber is disposed close to the liquid bead on the upstream side of the support in the traveling direction of the support, and the air is carried by the negative pressure to suppress the wind caused by the carrier air. The vibration of the liquid bead. Similarly, in Japanese Patent Publication 2000- In the publication No. 79621, a suction box for attracting liquid beads is provided. The suction box is divided into a first negative pressure region to a third negative pressure region, and the pressure is reduced. In the first negative pressure region, the periphery of the liquid bead is attracted throughout the width direction of the liquid bead, and the periphery of both sides in the width direction of the liquid bead is sucked in the second negative pressure region, and the liquid bead is removed from the third negative pressure region. Both sides are attracted. By this suction, the entrainment of air between the casting film and the support (hereinafter referred to as air entrapment), and the casting of the liquid bead and the support are suppressed. Line stabilization.

When a suction device such as a suction box is used, air is caught in the side surface at the end portion in the width direction of the liquid bead, and when the casting speed (the traveling speed of the support body) is increased, the air that is entrained becomes a bubble and appears in the flow. On the film, due to the bubbles, cracking or the like occurs during stretching, and productivity is lowered. In the Japanese Patent Publication No. Hei 10-264185, a blowing nozzle or a pressurizing box is disposed on the downstream side of the traveling direction of the support in the direction in which the liquid droplets travel, thereby suppressing the entrapment of air.

Further, in Japanese Laid-Open Patent Publication No. 2005-104148, a windshield is disposed on the upstream side and the downstream side of the support in the traveling direction of the support, thereby preventing the wind from flowing to the liquid bead. The wind deflector has a labyrinth seal between it and the support.

However, with the increase in size and weight of flat panel displays in recent years, the thickness of the manufactured film has also been increased. In order to produce a thin film more efficiently, in addition to being formed thin by stretching in the stretching process after film formation, it is preferable to make the thickness thinner at the liquid bead stage, and to reduce the thickness of the liquid bead. The improvement was studied.

In order to make the bead thinner, for example, the thickness of the bead of the die spout is not changed, but the walking speed of the support is increased to make the thickness of the bead before the contact with the support is thinned, and the discharge port of the mold is The thickness of the bead is set to be thinner than the conventional one. However, if the liquid bead is cast thinner, even if there is no problem with the thickness of the bead until now, the liquid bead is easily affected by the carrying wind in accordance with the amount of thinning.

For example, when the windshield associated with the movement of the support body is cut off by the wind shield described in Japanese Laid-Open Patent Publication No. 2004-114328, if the liquid bead is made thin, a long thickness does not occur in the width direction. All. Since the thickness unevenness changes in the traveling direction of the support body, it becomes a step-shaped unevenness change which changes into a waveform in the traveling direction, and is required to be improved. Further, the stepped unevenness is a periodic thickness unevenness caused by the vibration of the liquid bead generated in the casting direction, and if it is deteriorated, it can be visually confirmed by an evaluation method described later.

In the decompression chamber described in Japanese Patent Laid-Open Publication No. 2010-158834, When the bead is thinned, the bead is easily vibrated by the air pressure generated by the negative pressure, and the same planar failure occurs. Moreover, due to the vibration of the liquid bead, the entrapment of air is liable to occur. When air remains between the support and the liquid bead, the air becomes a bubble and enters between the cast film formed by casting the dope on the support and the support. The entrapment of the air sometimes progresses to breakage of the cast film when it is peeled off from the support after the cast film is dried. At this time, the casting stops, and a large amount of time and labor are required before the start of the casting. Therefore, it is required to suppress the entrapment of air.

When the inside is divided into three negative pressure regions to attract the periphery of the liquid bead by the suction box described in Japanese Laid-Open Patent Publication No. 2000-79621, since the suction is divided into three negative pressure regions, the suction box itself becomes In addition to the complicated structure, it is also necessary to slightly adjust the pressure setting of each negative pressure region. Also, since there are three negative pressure regions, three blowers are required, resulting in an increase in equipment cost. In addition, when the traveling speed of the support is 50 m/min or more, the casting of the liquid droplets is difficult, and it is difficult to stably maintain the casting line due to the suction of the three negative pressure regions. Air is involved.

In the blowing nozzle or the pressure tank described in Japanese Patent Publication No. Hei 10-264185, the liquid bead is disposed on the downstream side in the traveling direction of the support, and the liquid bead can be pressed back to the upstream side, that is, the mold side, and Correspondingly, the line where the liquid bead is connected to the support, that is, the casting line, is stabilized. However, in order to press the liquid ball back to the upstream side, it is necessary to increase the wind pressure of the blowing nozzle or the pressurizing tank, and as the liquid bead is thinned, the liquid bead becomes easy to vibrate. Due to this vibration, a long thickness unevenness occurs in the width direction, which changes in the traveling direction of the support body, and thus becomes a step-shaped unevenness change which changes in a traveling direction into a waveform.

Japanese Laid-Open Patent Publication No. 2005-104148 discloses that a labyrinth seal is provided on the windshield to suppress the wind from entering the liquid bead. However, since the labyrinth seal is disposed on the upstream side and the downstream side in the traveling direction of the support body away from the mold, It can suppress the air pressure vibration generated near the mold. Further, since the labyrinth seal is disposed on the upstream side and the downstream side of the traveling body traveling direction with respect to the decompression chamber, the air pressure vibration caused by the decompression chamber cannot be suppressed. Therefore, the obtained film becomes a step-shaped unevenness in which the thickness changes in the conveying direction.

Further, the labyrinth seal itself has failed to remove the air pressure fluctuation of the wind carried by the traveling body in accordance with the band component, and the air pressure vibration cannot be effectively suppressed.

It is an object of the present invention to provide an air pressure vibration that can be effectively removed, and When a thin film is produced in a solution, productivity is improved by high-speed casting, and a labyrinth seal, a casting device, and a solution film which are caused by a step-type unevenness failure and a flow stop due to air entrapment can be suppressed. Equipment and methods.

The labyrinth seal of the present invention includes a first seal portion and a second seal portion, and is disposed close to the surface of the traveling body to be traveled, and is provided on the windshield member that carries the wind carried by the shield surface. The first sealing portion is formed on a surface of the wind shield that faces the surface and has a first groove. The first groove is formed long in a direction crossing the traveling direction of the traveling body. The first groove is divided into three or more in the traveling direction. The second sealing portion has a second groove having a groove width or a groove depth different from that of the first groove. The second groove is divided into three or more in the traveling direction.

It is preferable that the labyrinth seal further includes a third sealing portion. The third sealing portion is adjacent to the second sealing portion. The third seal portion has a third groove having a groove width or a groove depth different from that of the first groove and the second groove. The third groove is divided into three or more in the traveling direction.

It is preferable that the groove width and the groove depth are combined with a frequency band based on the air pressure vibration of the wind.

The casting device of the present invention includes a traveling support, a mold, a wind shield, and a labyrinth seal. The mold discharges the dope from the discharge port toward the support. The mold forms a liquid bead between it and the support and forms a cast film on the surface of the support. The windshield member blocks the wind caused by the walking of the support body. The wind-shielding member is disposed closer to the surface of the support body than the liquid bead on the upstream side in the traveling direction of the support body, and is disposed along the liquid droplet. The labyrinth seal is disposed on the opposite side of the wind shield facing the support. The labyrinth seal has a first seal portion and a second seal portion. The first sealing portion is formed on the opposing surface and has a first groove. The first groove is formed to be long in a direction crossing the traveling direction. The first groove is divided into three or more in the traveling direction. The second sealing portion has a second groove having a groove width or a groove depth different from that of the first groove. The second groove is divided into three or more in the traveling direction.

The groove width is preferably 3 mm or more and 30 mm or less, and the groove depth is preferably 1 mm or more and 20 mm or less.

The solution film forming apparatus of the present invention includes a traveling support body, a mold, a wind shield member, a labyrinth seal, and a drying device. The mold discharges the dope from the discharge port toward the support. The mold forms a liquid bead between it and the support and forms a cast film on the surface of the support. The windshield member blocks the wind caused by the walking of the support body. The windshield component is in the direction of the support body than the liquid bead The upstream side is located close to the surface of the support and is disposed along the liquid droplets. The labyrinth seal is disposed on the opposite side of the wind shield facing the support. The labyrinth seal has a first seal portion and a second seal portion. The first sealing portion is formed on the opposing surface and has a first groove. The first groove is formed to be long in a direction crossing the traveling direction. The first groove is divided into three or more in the traveling direction. The second sealing portion has a second groove having a groove width or a groove depth different from that of the first groove. The second groove is divided into three or more in the traveling direction. The drying device peels off the cast film from the support and performs drying.

The solution film forming method of the present invention includes a cast film forming step and a drying step. In the cast film forming step, a casting film is formed using a casting device. The casting device has a walking support, a mold, a wind shield, and a labyrinth seal. The cast film is formed on the support. The mold discharges the dope from the discharge port toward the support. The mold forms a liquid bead between it and the support and forms a cast film on the surface of the support. The windshield member blocks the wind carried by the walking body. The wind-shielding member is disposed closer to the surface of the support body than the liquid bead on the upstream side in the traveling direction of the support body, and is disposed along the liquid droplet. The labyrinth seal is disposed on the opposite side of the wind shield facing the support. The labyrinth seal has a first seal portion and a second seal portion. The first sealing portion is formed on the opposing surface and has a first groove. The first groove is formed to be long in a direction crossing the traveling direction. The first groove is divided into three or more in the traveling direction. The second sealing portion has a second groove having a groove width or a groove depth different from that of the first groove. The second groove is arranged in three or more different directions in the traveling direction. In the drying step, the cast film is peeled off from the support and dried.

According to the present invention, the air pressure vibration of the wind carried by the circumferential surface of the walking can be eliminated in accordance with the frequency band. According to the casting device, the solution film forming apparatus and the method of the present invention, the labyrinth seal member is used for the windshield member, and the vibration of the liquid bead caused by the wind can be suppressed, and the step unevenness can be effectively suppressed while being generated. A thin film is produced.

10‧‧‧solution film making equipment

11‧‧‧casting device

12‧‧‧ tenter

13‧‧‧Drying device

14, 15‧‧‧ slitting machine

16‧‧‧Winding device

21‧‧‧1st roller

22‧‧‧2nd roller

23‧‧‧Conveyor belt

24‧‧‧ Guide roller

25‧‧‧Mold

25A‧‧‧Export

26A, 26B, 89‧‧‧Attraction box

27, 70‧‧‧ wind block

27A‧‧‧Conveyor belt facing surface of windshield 27

28A, 28B, 28C, 36‧‧‧ catheter (membrane dryer)

29‧‧‧ peeling roller

30‧‧‧Liquor

31, 105‧‧‧ liquid beads

32, 106‧‧‧ cast film

32A‧‧‧ bubbles

33‧‧‧film

33A‧‧‧roll film

34‧‧‧ clip

35‧‧‧Decompression chamber

38‧‧‧roll

40, 41‧‧‧ bracket

43‧‧‧ Triangle cylinder

43A‧‧‧ horizontal board

43B‧‧‧ vertical board

43C‧‧‧ inclined board

44A, 44B‧‧‧ side panels

45‧‧‧ attracting mouth

46‧‧‧1st partition

47‧‧‧2nd partition

48‧‧‧Attraction room

50‧‧‧ bearing

51‧‧‧ Guide ring

51A‧‧‧Guide

52, 92, 93‧‧‧ internal thread ring

52A, 92A, 93A‧‧‧ internal thread

53‧‧‧1st rotating shaft

54‧‧‧2nd rotation axis

53A, 54A, 90A, 90B‧‧‧ External thread

53B, 54B‧‧ Guidance Department

55, 95‧‧‧ suction tube

55A‧‧‧Flange

56‧‧‧through ring

57‧‧‧ suction pump

58‧‧‧ Carrying the wind

59, 69, 74‧‧‧ labyrinth seals

61, 71, 81‧‧‧1st seal

62, 72, 82‧ ‧ 2nd seal

63, 73, 83‧ ‧ third seal

65, 66, 67, 75, 76, 77‧‧‧ Sealing unit

65A, 66A, 67A, 75A, 76A, 77A‧‧‧ teeth

65B, 66B, 67B, 75B, 76B, 77B‧‧‧ slots

90‧‧‧Rotary axis

91‧‧‧Guide axis

94‧‧‧Fixed ring

96‧‧‧wind shield

Conveyor belt facing surface of 96A‧‧ windshield 96

BCA‧‧‧Liquor Central District

BSA‧‧‧ Both ends of the liquid bead

BLN, BLO‧‧‧casting line

BTA‧‧‧ vertex area

G‧‧‧ gap

H1‧‧‧ tooth height, groove depth

L1‧‧‧Attraction length

L2‧‧‧ tooth width

L31, L32, L33‧‧‧ slot width

OS‧‧‧ offset length

Summit of T1‧‧‧

X‧‧‧ direction

Y‧‧‧The direction of travel of the conveyor belt

Fig. 1 is a side view showing an outline of a solution film forming apparatus of the present invention.

Fig. 2 is a perspective view showing an outline of a periphery of a mold of a casting device.

Fig. 3 is a longitudinal cross-sectional view showing the relationship between a mold, a liquid bead, and a suction box in the first embodiment.

Fig. 4 is a perspective view showing a portion of the inclined plate of the suction box cut away.

Fig. 5 is a plan view showing a portion of the inclined plate of the suction box cut away.

Fig. 6 is a front view showing the arrangement of the suction box with respect to the liquid bead.

Fig. 7 is a plan view showing a bead casting line and a casting film in a state in which both ends of the liquid bead are sucked by the suction box.

Fig. 8 is a plan view showing a conventional type of liquid bead casting line and a cast film which are not attracted to both end portions of the liquid bead.

Figure 9 is a side view showing the labyrinth seal of the wind block.

Fig. 10 is a cross-sectional view showing another embodiment of the labyrinth seal of the windshield block.

Figure 11 is a cross-sectional view showing another embodiment of the labyrinth seal of the windshield block.

Figure 12 is a plan view showing a suction box of another embodiment in which a plurality of partitions are moved by one rotating shaft, with a portion of the inclined plate being cut.

Fig. 13 is a bottom view showing a windshield-integrated suction box having a windshield and a suction box.

As shown in FIG. 1, the solution film forming apparatus 10 is provided with a casting device 11, a tenter 12, a slitter 14, a drying device 13, a slitting machine 15, and a winding device 16 in this order from the upstream side, and the components are connected in series. connection.

The casting device 11 includes an endless belt (support) 23, a guide roller 24, a mold 25, suction boxes (suction members) 26A and 26B, a wind block (wind shield) 27, a duct (film dryer) 28A, and 28B, 28C and peeling roller 29. The conveyor belt 23 is formed in a ring shape and functions as a metal casting support. This conveyor belt 23 is wound around the circumferential surfaces of the first drum 21 and the second drum 22. The first roller 21 is rotationally driven by a motor (not shown), and the endless belt 23 travels in a direction indicated by an arrow Y. In the following description, the traveling direction Y of the conveyor belt 23 may be referred to as a belt running direction Y or a Y direction. The guide roller 24 supports the upper conveyor belt 23 from the inner side.

As shown in FIG. 2, the mold 25 is disposed above the first drum 21. The mold 25 continuously flows out of the discharge port 25A (see FIG. 3) as the liquid bead 31 with respect to the surface of the traveling belt 23 during traveling. Thereby, the casting film 32 is formed on the conveyor belt 23. The dope 30 is produced by dissolving a cellulose halide in a solvent, for example, in a dope production line (not shown), and supplies it to the mold 25.

A pair of suction boxes 26A and 26B are disposed upstream of the traveling beads Y of the conveyor belt 23 with respect to the liquid droplets 31 from the mold 25.

As shown in FIG. 1, in order to increase the manufacturing speed, the casting film 32 which faces the peeling roller 29 is heated by the 2nd drum 22 and the conveyor belt 23. Further, at the casting position, the conveyor belt 23 is cooled by the first drum 21, and excessive temperature rise is suppressed. Therefore, the first roller 21 and the second roller 22 have temperature adjustment devices (not shown).

The ducts 28A, 28B, and 28C are arranged along the traveling path of the conveyor belt 23, and blow dry air. The temperature controller (not shown) independently controls the temperature, humidity, and flow rate of the dry air. The temperature of the casting film 32 is adjusted by the temperature and flow rate control of the drying air and the temperature control by the temperature adjustment means of the first roller 21 and the second roller 22 itself, and the solvent is evaporated from the casting film 32 to be cast. Drying of film 32. Further, the casting film 32 is cured to such an extent that it can be conveyed by the tenter 12.

With respect to the mold 25, a peeling roller 29 is disposed on the upstream side of the traveling direction Y of the conveyor belt 23 in the vicinity of the circumferential surface of the first drum 21. The peeling roller 29 supports the cast film 32 when the dried cast film 32 is removed from the conveyor belt 23 in a state containing a solvent. The stripped cast film 32 is guided as a film 33 to the tenter 12.

In the tenter 12, the both sides of the film 33 are gripped by the clip 34, and the dry air is sent from the duct 36, thereby imparting a tension toward the film width direction X indicated by an arrow X while conveying the film 33, thereby expanding The width of the film 33. In addition, since the respective width directions of the film 33, the casting film 32, and the liquid droplets 31 coincide with each other, the width direction thereof is indicated by the symbol X, and is sometimes referred to as the X direction in the present specification.

The slitter 14 cuts off both sides including the holding marks caused by the clips 34 of the tenter 12. The film 33 which is cut off at both sides is sent to the drying device 13.

In the drying device 13, the film 33 is wound around a plurality of rolls 38 and conveyed. The temperature or humidity of the atmosphere inside the drying device 13 is adjusted by a temperature adjuster (not shown), and the solvent evaporates from the film 33 during the conveyance of the film 33.

The film that has passed through the drying device 13 is cut off by the slitter 15 to be, for example, the target product width or the like. The film 33 which is cut off at both sides is taken up in a roll shape by the winding device 16. The roll film 33A obtained by the present invention can be especially used for a retardation film or a polarizing plate protective film.

Further, a second tenter (not shown) may be provided on the downstream side of the film running of the drying device 13. The second tenter has the same structure as the tenter 12, and has a clip and a catheter. The clip holds the film 33 and extends in the width direction. At the time of stretching, the film 33 having desired optical characteristics can be obtained by controlling the stretching ratio and temperature conditions and the like. When the second tenter is installed, it is preferable to arrange the slitter 15 downstream of the second tenter to cut off the both sides including the holding trace by the clip of the second tenter.

As shown in FIG. 2, the suction boxes 26A and 26B are disposed near the liquid droplets 31 and are disposed at both end portions of the casting film 32 in the width direction X. The suction boxes 26A and 26B are attached to the mold 25 via the bracket 40. The opposite faces of the conveyor belts of the suction boxes 26A, 26B are formed as smooth surfaces that are parallel with respect to the circumferential surface of the conveyor belt 23.

As shown in FIG. 4, the suction box 26A disposed at one end portion of the liquid bead 31 in the width direction X blocks the triangular cylinder 43 composed of the horizontal plate 43A, the vertical plate 43B, and the inclined plate 43C by the side plates 44A and 44B. Both ends are formed into a triangular column shape. The horizontal plate 43A is disposed substantially parallel to the conveyor belt 23. Further, the inclined plate 43C is disposed in parallel with the front end surface of the mold 25.

As shown in FIG. 3, a slit-like gap is provided between the horizontal plate 43A and the inclined plate 43C. The suction port 45 of the suction box 26A is formed by the gap.

As shown in FIG. 4, in the suction box 26A, the two partition plates 46, 47 are mounted to be movable with respect to the width direction X of the liquid droplet 31. In the following description, reference numeral 46 is referred to as a first separator, and reference numeral 47 is referred to as a second separator. The first partition plate 46 and the second partition plate 47 are formed in the same shape as the side plates 44A and 44B and are slightly smaller than the side plates 44A and 44B, and are slidable in the suction box 26A. The first rotating shaft 53 and the second rotating shaft 54 are attached to the first partition plate 46 and the second partition plate 47 by the guide ring 51 and the female thread ring 52. The suction box space sandwiched by the first partition plate 46 and the second partition plate 47 serves as the suction chamber 48. The first rotating shaft 53 and the second rotating shaft 54 are rotatably attached to the side plates 44A and 44B by bearings 50.

In Fig. 5, the first rotating shaft 53 is formed with a male screw portion 53A only in the right half portion thereof, and the left half portion serves as the guide portion 53B. The male screw portion 52A of the female screw ring 52 is screwed into the male screw portion 53A, and the guide hole 51A of the guide ring 51 is fitted to the guide portion 53B. As a result, as shown in FIG. 4, when the first rotating shaft 53 is rotated clockwise, the first partition plate 46 is moved to the right in the X direction, and when the first rotating shaft is rotated counterclockwise, the first partition is opened. The plate 46 moves to the left. Similarly, as shown in FIG. 5, when viewed from the side of the back surface (vertical plate 43B), the second rotating shaft 54 is formed with the male screw portion 54A only in the left half portion thereof, and the right half portion serves as the guide portion 54B. Further, the female screw portion 52A of the female screw ring 52 is screwed to the male screw portion 54A, and the guide portion 54B is fitted with a guide. Since the guide hole 51A of the ring 51 is rotated by the second rotation shaft 54, the second partition 47 moves to the right or left in the X direction.

As shown in FIG. 6, the length of the suction port 45 in the X direction (hereinafter referred to as the suction port length) L1 and the liquid droplet can be changed by the movement of the first separator 46 and the second separator 47 in the X direction. The amount of shift in the X direction from the end of 31 to the suction port 45 (hereinafter referred to as offset length) OS. The suction port length L1 is, for example, 10 mm or more and 50 mm or less. Further, the offset length OS is, for example, 5 mm or more and 30 mm or less. Thereby, the suction boxes 26A and 26B can attract a range of, for example, 10 mm or more and 50 mm or less from the both ends of the liquid bead 31 toward the center portion. Further, it is preferable to appropriately change the offset length OS depending on the type and viscosity of the dope 30, the thickness, width, length, and the like of the bead 31. In addition, since the suction air volume can be adjusted by changing the length L1 of the suction port, for example, as shown in Japanese Laid-Open Patent Publication No. 2000-79621, different negative pressures are generated with respect to the first to third negative pressure regions, so that it is not necessary to provide three. The blower can suppress equipment costs.

As shown in FIG. 5, the suction pipe 55 is attached to the 2nd partition plate 47 by the flange part 55A. The suction pipe 55 is inserted through the through ring 56 of the outer side plate 44B, and the suction source connected to the outside is connected to, for example, the suction pump 57 shown in Fig. 4 .

The suction box 26B disposed at the other end portion of the liquid bead 31 in the width direction X is also configured to be the same as the suction box 26A. However, the first rotating shaft 53, the second rotating shaft 54, and the suction pipe 55 provided in the suction box 26B are in the center portion in the width direction X of the liquid droplet 31, and the first rotating shaft 53 and the second rotating shaft that face the suction box 26A. 54. The outer side of the opposite side of the protruding side of the suction tube 55 protrudes.

In the present embodiment, as shown in FIG. 7, the suction boxes 26A and 26B are disposed on the upstream side of the belt running direction Y on the upstream side of the liquid droplet 31 in the vicinity of the liquid droplets 31. By the suction boxes 26A and 26B, both ends of the liquid droplets 31 are sucked at the both end portions BSA of the liquid bead. Therefore, the casting line BLN that the liquid bead 31 is in contact with the conveyor belt 23 is compared with the conventional type of casting line BLO (indicated by a chain double-dashed line in the figure) which is convexly curved in the traveling direction Y of the conveyor belt, as indicated by a broken line. It is linear in the central portion BCA of the liquid bead beyond the BSA at both end portions of the bead. Therefore, unlike the conventional type of casting line BLO shown in Fig. 8, the air enters from the apex portion BTA which is curved into a convex shape, and air does not become the bubble 32A between the casting film 32 and the conveyor belt 23, and the air roll The production of the ingress is suppressed.

Fig. 8 shows a conventional casting line BLO in plan view. On the casting line BLO, the center of the width direction X of the liquid droplet 105 becomes the vertex T1, and the film is formed along the conveyor belt by high speed film formation. The traveling direction Y becomes a substantially circular arc. Therefore, air enters from the apex portion BTA bent into a convex shape, and a bubble 32A is generated between the conveyor belt 23 and the casting film 106 in the traveling direction Y of the conveyor belt. On the other hand, in the present embodiment, as shown in Fig. 7, the both ends of the liquid bead BSA are attracted, and the casting line BLN is as shown by the solid line, and is in the center of the liquid bead beyond the BSA at both end portions of the bead. The area BCA is linear. Therefore, in the conventional type as shown in Fig. 8, the air enters from the apex portion BTA which is curved into a convex shape, and becomes a bubble 32A between the conveyor belt 23 and the casting film 106, and generation of air entrapment is suppressed. Therefore, the casting film 32 does not remain on the peeling roller 29 (see FIG. 1) by the air bubbles 32A, and does not cause a casting stop or the like due to the residual.

However, depending on the requirements for the film formation of the film 33, it is necessary to cause the conveyor belt 23 to travel at a high speed in a range of, for example, 50 m/min or more and 100 m/min or less. By the high speed running of the conveyor belt 23, the conveyor belt 23 carries air, and a carrying wind 58 is generated on the surface of the conveyor belt 23. In order to eliminate the influence of the portable wind 58, in the present embodiment, as shown in Fig. 2, a wind block 27 is disposed between the pair of suction boxes 26A and 26B. The wind block 27 blocks the carrying wind 58 on the upstream side of the liquid bead 31, so that the carrying wind 58 does not blow to the liquid bead 31. The wind block 27 is attached to the mold 25 via the bracket 41.

A gap G (see FIG. 9) is provided between the conveyor belt 23 and the windshield 27, and the windshield 27 does not come into contact with the traveling conveyor belt 23. Therefore, the lower portion of the carrier wind 58 that is not completely blocked passes through the gap G between the conveyor belt 23 and the windshield block 27.

In the conventional case where the traveling speed of the conveyor belt 23 is about 30 m/min, as shown in Fig. 8, the carrying wind accompanying the traveling of the conveyor belt 23 has less influence on the liquid droplet 105, and it rarely develops into a cast film. The stepped shape of 106 is uneven. On the other hand, when the traveling speed of the conveyor belt 23 is set to a high speed of 50 m/min or more as required for the film formation, the liquid bead 105 is also thinned as the speed is increased, and it is susceptible to the wind. In the past, the windshield described in Japanese Patent Laid-Open Publication No. 2004-114328 is used to block the wind, but the lower portion of the wind that passes through the gap between the windshield and the conveyor belt 23 is generated after passing through the windshield. swirl. The generation of the vortex and the vibration imparted to the liquid droplet 105 by the vortex were confirmed by experiments by the inventors.

Therefore, as shown in FIG. 9, a labyrinth seal 59 is formed on the belt facing surface 27A of the windshield 27. The labyrinth seal 59 has a first seal portion 61, a second seal portion 62, and a third seal portion 63. The first sealing portion 61 has three sealing units 65 in the Y direction, and the sealing unit has teeth (plate-like projections) 65A parallel to the X direction and the Y direction A groove 65B adjacent to the tooth 65A and parallel to the X direction. The height H1 of the tooth 65A is the same as the depth of the groove 65B, preferably 1 mm or more and 20 mm or less, more preferably 3 mm or more and 15 mm or less.

The length L2 of the tooth 65A in the Y direction is preferably 1 mm or more and 10 mm or less, more preferably 1 mm or more and 5 mm or less. Further, the Y direction length (width) L31 of the groove 65B is preferably 3 mm or more and 30 mm or less, more preferably 3 mm or more and 20 mm or less.

The number of the respective sealing units 65 in the first sealing portion 61 is three, but it may be three or more. Further, the number of the arrays of the sealing units 65 is not particularly limited. However, from the viewpoint of equipment efficiency, 10 or less is preferable, and 5 or less is more preferable.

The second sealing portion 62 and the third sealing portion 63 also have three sealing units 66 and 67 similarly to the first sealing portion 61. The sealing units 66, 67 have teeth 66A, 67A and grooves 66B, 67B. In each of the sealing units 66 and 67, the widths L32 and L33 of the grooves 66B and 67B are gradually wider toward the liquid bead 31 in the Y direction than the groove width L31 of the first sealing portion 61, and the points are different. The outer structure is the same.

By setting the width and depth of the grooves 65B to 67B of the respective sealing units 65 to 67, the number of times of the grooves 65B to 67B and the teeth 65A to 67A or the teeth 65A to 67A and the grooves 65B to 67B to a constant range, it is possible to suppress the number of grooves. The gap G between the conveyor facing surface 27A of the wind block 27 and the conveyor belt 23 enters the air pressure vibration of the specific frequency band caused by the wind 58. This finding was obtained by various experiments for changing the sizes of the teeth 65A to 67A and the grooves 65B to 67B of the labyrinth seal 59 and their number of repetitions (number of arrays) in the Y direction. That is, various experiments were carried out to obtain the following findings: the widths L31 to L33, the depths H1, the grooves 65B to 67B, and the teeth 65A to 67A or the teeth 65A to 67A and the grooves 65B to 67B of the grooves 65B to 67B are set to a certain range. Thereby, the air pressure vibration of a specific frequency band can be effectively suppressed. Thereby, the air pressure vibration of the specific frequency band carrying the wind 58 can be suppressed or cut off by the labyrinth seal 59.

When the gap G is not 3 mm or less, the carrier wind 58 does not pass through the gap G, and the effect of reducing the air pressure vibration is lowered. Further, the closer the lower limit value is to 0 mm, the more preferable. However, when it is close to 0 mm, the belt facing surface 27A of the windshield 27 may come into contact with the conveyor belt 23 due to the thickness error of the conveyor belt 23 and the circumferential surface error of the first drum 21. Therefore, the lower limit value is preferably 1 mm or more.

The depth H1 of the grooves 65B, 66B, and 67B (the height H1 of the teeth 65A, 66A, and 67A) is preferably 1 mm or more and 20 mm or less, more preferably 3 mm or more and 15 mm or less. If less than When 1 mm is used, wind turbulence cannot be generated in the grooves 65B to 67B, and the pressure loss does not rise, so that the wind shielding effect is lowered. When it exceeds 20 mm, the effect of reducing the air pressure vibration is saturated, and a better effect cannot be obtained than the increase in the machining load caused by the deepening grooves 65B to 67B.

The widths L31, L32, and L33 of the grooves 65B, 66B, and 67B are preferably 3 mm or more and 30 mm or less, more preferably 3 mm or more and 20 mm. If it is less than 3 mm, wind turbulence cannot be generated in the grooves 65B, 66B, and 67B, the pressure loss does not rise, and the effect of reducing the air pressure vibration is lowered. When it exceeds 30 mm, the effect of reducing the air pressure vibration is saturated, and a better effect cannot be expected. Also, the processing load is also increased.

The widths L31, L32, and L33 of the grooves 65B, 66B, and 67B are preferably determined in combination with the frequency band to be cut off by the air pressure vibration caused by the wind 61. For example, by setting the groove widths L31, L32, and L33 to 3 mm, it is possible to cut off the air pressure vibration in the air pressure in the frequency band of 100 Hz or more and less than 150 Hz. In addition, by setting the groove widths L31, L32, and L33 to 10 mm, it is possible to cut off the air pressure vibration in the air pressure range of 50 Hz or more and less than 100 Hz. Further, by setting the groove widths L31, L32, and L33 to 20 mm, it is possible to cut off the air pressure vibration of less than 50 Hz. Further, the frequency band and the groove widths L31, L32, and L33 in the air pressure vibration to be cut off are not limited to the above relationship. The frequency band in the air pressure vibration to be cut can be changed by changing the groove widths L31, L32, and L33. These relationships can be experimentally performed by forming teeth and grooves in which the groove width and the groove depth H1 are changed, thereby specifying a frequency band having a truncation effect.

It is preferable that the widths L2 of the teeth 65A, 66A, and 67A are 1 mm or more and 20 mm or less. If it is less than 1 mm, the strength will be insufficient and the durability will be lowered. When it exceeds 20 mm, only the length of the labyrinth seal 59 in the Y direction is increased, and the effect of reducing the air pressure vibration is lowered.

Further, both ends of the grooves 65B to 67B of the labyrinth seal 59 may be opened or closed. However, if it is opened, the wind entering each of the grooves 65B to 67B easily escapes from both end portions, so that the wind shielding effect with respect to the liquid bead 31 becomes higher.

Fig. 10 shows a labyrinth seal 69 of the second embodiment in which the teeth 65A to 67A of the sealing units 65 to 67 and the first to third sealing portions 71 to 73 of the grooves 65B to 67B are exchanged in the Y direction. Thus, even if the teeth 65A to 67A and the grooves 65B to 67B are exchanged in the Y direction, the vibration in the specific frequency band can be cut off. The same components as those of the above-described embodiment are denoted by the same reference numerals and the description thereof will not be repeated. The order of arrangement of the first sealing portions 61, 71, the second sealing portions 62, 72, and the third sealing portions 63, 73 in the traveling direction Y of the conveyor belt can be appropriately changed. Each slot 65B to 67B are formed to extend in the X direction orthogonal to the traveling direction Y of the conveyor belt, but the direction in which the grooves 65B to 67B are formed may be intersected with the traveling direction Y of the conveyor belt, and the crossing angle is not limited to a right angle. In Fig. 10, a windshield provided with a labyrinth seal 69 is denoted by reference numeral 70.

Fig. 11 shows a first sealing portion 81 to a windshield block 78 of another embodiment in which the grooves 75B to 77B of the labyrinth seal 74 are formed shallower than the grooves in the labyrinth seal 59 of the first embodiment. 3 sealing portion 83. The first to third sealing portions 81 to 83 have three sealing units 75 to 77 which are continuously formed in the Y direction. In Fig. 11, reference numerals 75A, 76A, and 77A are attached to the respective teeth of the sealing units 75, 76, and 77. Even if the depth H1 of each of the grooves 75B to 77B is shallower than that of the first embodiment, the vibration of the specific frequency band can be cut off.

In each of the above embodiments, the suction pressure BP of the suction boxes 26A and 26B is preferably -3000 Pa or more to 150 Pa or less, and more preferably -1000 Pa or more to 500 PaPa or less. The casting device 11 includes a chamber (not shown) that houses the mold 25, the first roller 21, the second roller 22, and the conveyor belt 23. The suction pressure BP based on the suction boxes 26A and 26B is a value based on the pressure in the vicinity of the upper portions of the suction boxes 26A and 26B in the chamber. However, the pressure in the vicinity of the upper portion of the mold 25 may be used as a reference value. If it exceeds -150 Pa, the guidance of the carrying wind 58 cannot be sufficiently performed. Further, if it is less than -3000 Pa, the bead itself is also deformed by the negative pressure, resulting in deterioration of the surface.

In each of the above embodiments, the wind blocks 27, 70, and 78 are provided on the upstream side of the conveyor belt traveling direction Y with respect to the mold 25. However, the decompression chamber may be further provided on the upstream side of the windshields 27, 70, and 78. . The decompression chamber sucks the air in the upstream side region of the wind blocks 27, 70, 78 to decompress the region, and suppresses the carried wind 58 from entering the bead 31. It is preferable that the suction pressure based on the decompression chamber is smaller than the suction pressure of the suction boxes 26A, 26B. That is, it is preferable that the pressure in the decompression chamber is larger than the pressure inside each of the suction boxes 26A, 26B. Also, a decompression chamber can be used instead of the wind blocks 27, 70, 78.

In the suction boxes 26A and 26B of the above-described embodiment, the first partition plate 46 and the second partition plate 47 are moved by the first rotating shaft 53 and the second rotating shaft 54. However, as shown in FIG. 12, instead of the above, the suction box 89 which moves the 1st partition 46 and the 2nd partition 47 by one rotation shaft 90 and one guide shaft 91 may be used. The rotating shaft 90 is rotatably attached to the both side plates 44A and 44B of the suction box 89 via the bearing 50. The guide shaft 91 is fixed to the side plates 44A, 44B by a fixing ring 94. The same components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

The rotating shaft 90 is attached to the pair of partition plates, that is, the first partition 46 and the second partition 47 via the internally threaded rings 92 and 93. The rotating shaft 90 has external thread portions 90A and 90B that are opposite to each other from the center toward both end portions. One internal thread ring 92 has an internal thread portion 92A that is screwed to the external thread portion 90A, and the other internal thread ring 93 has an internal thread portion 93A that is screwed to the external thread portion 90B. The guide shaft 91 is attached to the pair of partition plates, that is, the first partition plate 46 and the second partition plate 47 via the guide ring 51. The guide ring 51 has a guide hole 51A that slidably holds the guide shaft 91.

When the rotating shaft 90 is rotated to one side, the pair of partition plates, that is, the first partition plate 46 and the second partition plate 47 are brought close to each other via the female screw rings 92 and 93, and the first partition plate is rotated to the other side. 46. The second partition 47 is separated. Thereby, the width of the suction chamber 48 can be changed. Therefore, when the viscosity of the dope 30 or the thickness of the liquid droplet 31 changes, the width of the suction port 45 of the suction box 89 can be optimized by rotating the rotating shaft 90. By changing the width of the suction port 45, the suction air volume can be adjusted without changing the negative pressure of the air blower. Further, the mechanism for moving the first separator 46 and the second separator 47 in parallel is not limited to the above, and various mechanisms can be used. Further, the separator is not limited to a pair, and three or more sheets may be provided. In this case, each of the partition plates is provided so as to be movable in the width direction X of the liquid droplets 31, and the number of suction chambers partitioned by the respective partition plates in the suction box is two or more, whereby the suction can be set more carefully. Air volume and attraction area.

In the above embodiment, the suction pipe 55 is provided in the second partition plate 47. However, as shown in Fig. 12, the suction pipe 95 may be provided in the vertical plate 43B constituting the suction box 89 instead of the above. Further, although not shown, the suction pipe 95 may be provided in the inclined plate 43C constituting the suction box 89.

Further, although not shown, the suction boxes 26A, 26B, and 89 can be attached to move in the width direction of the liquid droplet 31 by using a displacement mechanism. At this time, it is possible to finely adjust the suction regions at both end portions of the liquid droplets 31 in accordance with the viscosity of the dope 30 or the like. Moreover, it is also easy to cope with the change in the width of the bead 31.

In the above embodiment, the windshield block 27 is disposed between the suction boxes 26A and 26B. However, as shown in Fig. 13, the windshield plate 96 may be made longer than the casting film 32 (see Fig. 2). For example, it is set to be the same length as the mold 25 in the X direction. A labyrinth seal 59 is formed long in the X direction on, for example, the entire surface of the belt facing surface 96A of the windshield 96. Further, suction boxes 26A and 26B are disposed at both end portions of the upper surface of the windshield 96 in the X direction. At this time, the gap between the suction boxes 26A, 26B and the conveyor belt 23 can be reduced by the labyrinth seal 59. The air pressure of the wind 58 is carried. Further, in the suction belts 26A and 26B of the first embodiment, the labyrinth seal 59 similar to the windshield 27 can be formed on the opposite side of the conveyor belt, thereby replacing the integral type of the windshield 96 and the suction boxes 26A and 26B.

In the above-described example, the side surface (conveyor surface) on which one side of the dope 30 is carried by the conveyor belt 23 that carries the wind system is not limited thereto. In other words, the wind can be carried as long as it is on the surface of the traveling body. Therefore, the labyrinth seals 59, 69, and 74 may be provided on the windshield member disposed close to the surface of the traveling body different from the conveyor belt 23. As the traveling body, there is a drum that serves as a support body instead of the conveyor belt 23 and that rotates in the circumferential direction. Further, as another example of the traveling body, there is an elongated material (mesh) in which a coating liquid is applied to a surface of a film having a multilayer structure by coating to form a coating film.

In the solution film forming apparatus of the present invention, the width of the film 33 as a product is preferably 600 mm or more, more preferably 1400 mm or more and 2500 mm or less. Further, it is also effective when the width of the film 33 is larger than 2,500 mm. Further, the film thickness of the film 33 is preferably 10 μm or more and 80 μm or less, more preferably 10 μm or more and 40 μm or less. The polymer which is a raw material of the film 33 is not particularly limited, and examples thereof include cellulose halides and cyclic polyolefins.

The thiol group used for the cellulose oxime in the present invention may be used alone or two or more kinds of fluorenyl groups may be used. When two or more kinds of fluorenyl groups are used, one of them is preferably an acetamino group. It is preferred that the ratio of the esterification of the cellulose to the cellulose group, that is, the degree of substitution of the thiol group, satisfies all of the following formulas (I) to (III). Further, in the following formulas (I) to (III), A and B represent the degree of substitution of a mercapto group, A is a degree of substitution of an ethylidene group, and B is a degree of substitution of a mercapto group having 3 to 22 carbon atoms. Further, it is preferred that 90% by mass or more of triacetylcellulose (TAC) is 0.1 mm or more and 4 mm or less.

The total substitution degree A+B of the fluorenyl group is preferably 2.20 or more and 2.90 or less, and more preferably 2.40 or more and 2.88 or less. Further, the degree of substitution B of the fluorenyl group having 3 to 22 carbon atoms is more preferably 0.30 or more, and particularly preferably 0.5 or more.

The details of the cellulose oxime are described in paragraphs [0140] to [0195] of Japanese Patent Laid-Open Publication No. 2005-104148. These descriptions can also be applied to the present invention. and, Additives such as solvents, plasticizers, deterioration inhibitors, ultraviolet absorbers (UV agents), optical anisotropy control agents, retardation inhibitors, dyes, matting agents, release agents, and stripping accelerators are also described in detail in Japanese patents. Paragraphs [0196] to [0516] of 2005-104148 are disclosed.

[Examples]

The height (groove depth) H1 of the teeth 65A, 66A, and 67A; the width L2 of the teeth 65A, 66A, and 67A; the widths L31 to L33 of the grooves 65B, 66B, and 67B; the clearance G; and the air pressure that can be cut off are performed. Experiments on the relationship between vibrations. Table 1 is a list showing the results of the experiment. In Experiment 1, the groove depth H1 was set to 3 mm, the tooth width L2 was set to 1 mm, the groove width L31 was set to 3 mm, the groove width L32 was set to 10 mm, the groove width L33 was set to 20 mm, and the number of cells was set. In the case of three, the frequency peak of the cutoff is obtained for a frequency band of 0 Hz or more and less than 50 Hz, 50 Hz or more and less than 100 Hz, and 100 Hz or more and less than 150 Hz. The truncated frequency peak is represented by a comparison with a frequency peak of 0.8 Pa cut off in Experiment 5 without a labyrinth seal, and the frequency peak cut in Experiment 1 is 0.4 Pa. Experiment 2 changed the groove depth H1 as compared with Experiment 1, thereby measuring the influence of the groove depth H1 on the cutting effect. Experiments 3 and 4 changed the number of cells compared with Experiment 1, thereby measuring the influence of the truncation effect when the number of cells was small (Experiment 3) and when the number of cells was large (Experiment 4). In addition, the band and the frequency peak which can be cut off are obtained by connecting the air pressure vibrating pickup and the amplifier to the FFT analyzer (SA-01 manufactured by Rion Co., Ltd.) so as not to be cast near the mold 25. The state in which the operation is performed offline with a total of three castings in the center of the width and the center is performed. Further, in the "width L3" column of "groove" in Table 1, the seal portion number "1" column indicates the groove width L31, the seal portion number "2" column indicates the groove width L32, and the seal portion number "3" column indicates the groove width. L33.

In Experiment 1 of Table 1, the peak frequency of the cutoff was 0.4 Pa, and it was found that the cut-off effect of carrying wind 58 was obtained. On the other hand, in Experiment 2 from the groove depth H1 of 3 mm of Experiment 1 to the groove depth H1 of 10 mm, the peak value of the cutoff was 0.1 Pa, and it was found that the cutting effect was the highest. Further, in Experiment 3 in which the number of cells was changed from "3" to "2" in Experiment 1, the peak frequency of the cutoff was 0.6 Pa, and the cutoff effect was lower than Experiment 1. Further, in Experiment 4 in which the number of cells was set to "5", the peak frequency of the truncation was 0.4, which was the same as when the number of cells was 3. Therefore, it is understood that the number of cells is preferably 3 or more and 5 or less. Further, in Experiment 5 without the labyrinth seal, the peak frequency of the cutoff was 0.8 Pa, and it was found that there was no cutoff effect.

Experiments were conducted to confirm the effects based on the suction boxes 26A and 26B. The results are shown in Table 2.

In the experiments 11 to 13, the suction boxes 26A and 26B shown in Figs. 2 to 4 are used to suck the both ends of the liquid bead 31 on the upstream side in the traveling direction Y of the conveyor belt, and as shown in Fig. 7, the casting line BLN is realized. Straight line. Further, the influence of the vibration of the liquid bead 31 caused by the wind 58 is excluded by using the wind block 27. After the casting film 32 is formed on the conveyor belt 23 by the solution film forming apparatus 10 shown in FIG. 1, the casting film 32 is peeled off as the film 33, and the film 33 is produced by the tenter 12 and the drying device 13, and The film 33 is taken up in a roll shape. The film 33 was composed of TAC, and the width was set to 200 mm in Experiment 11, 400 mm in Experiment 12, and 800 mm in Experiment 13, and the thickness was set to 10 μm, 30 μm, and 60 μm in each of Experiments 11 to 13.

In Experiment 14, the film 33 was produced under the same conditions as those of Experiment 11, except that the suction boxes 26A and 26B of the experiment 11 and the wind block 27 were removed.

In Experiment 15, in the same manner as in Experiment 11, except that the decompression chambers 35 indicated by two-dot chain lines in Fig. 1 were provided instead of the suction boxes 26A and 26B of the experiment 11 and the windshield block 27, Film 33.

As is clear from Table 2, in the experiments 11 to 13, no air entrapment occurred, and step unevenness did not occur. On the other hand, in the experiment 14, although the step shape unevenness did not occur, air entrapment occurred. Further, although air entrapment did not occur in Experiment 15, step unevenness occurred.

In addition, in Table 2, when air entrapment did not occur, the occurrence of air entrapment was evaluated as "A", and when air entrapment occurred, it was evaluated as "B". Further, when stepped unevenness was not generated, the step unevenness was evaluated as "A", and when stepped unevenness was generated, it was evaluated as "B".

Regarding the air entrapment, the cast film 32 including the casting line is photographed by a high speed camera, and the captured image is enlarged to 5 to 15 times and displayed on the display. Even if there is a small amount of air caught in, it is judged as B, and when it is not entrained with air, it is regarded as having a bubble suppressing effect, and it is judged as A. In addition, air entrapment is performed by visual confirmation of the display. However, it is also possible to perform image processing on an image displayed on the display, and automatically recognize the entrapment of air by pattern recognition or the like, thereby performing determination.

For uneven step shape, the obtained film is sampled at a predetermined size, and the sampled film is placed on a transparent film placing table, and the film is illuminated by a point light source (USHIO xenon lamp) from 1500 mm to 2000 mm above the film. Projecting the light through the film and film placement table onto the observation table to evaluate whether the projected light from the observation table can be visually observed. All. When it was confirmed by visual evaluation that the step shape was uneven, it was judged as B, and when the step shape unevenness was not confirmed, it was judged as A. In addition, evaluation was performed in a state where the film placement stage was tilted in a range of 45° or more and 60° or less with respect to the observation stage.

From the above results, it is understood that the effect of improving step unevenness and the effect of suppressing bubbles can be obtained. In addition, it is estimated that the same effect can be obtained under the actual production conditions, that is, when the width is, for example, 1400 mm or more and 2500 mm or less, or more than the range, and the thickness is 10 μm or more and 60 μm or less.

23‧‧‧Conveyor belt

27‧‧‧ wind block

27A‧‧‧ conveyor belt facing opposite

58‧‧‧ Carrying the wind

59‧‧‧Labyrinth seals

61‧‧‧1st seal

62‧‧‧2nd seal

63‧‧‧3rd seal

65‧‧‧ Sealing unit

65A‧‧‧ teeth

65B‧‧‧ slot

66‧‧‧Seal unit

66A‧‧‧ teeth

66B‧‧‧ slot

67‧‧‧ Sealing unit

67A‧‧‧ teeth

67B‧‧‧ slot

G‧‧‧ gap

H1‧‧‧ tooth height, groove depth

L2‧‧‧ tooth width

L31‧‧‧ slot width

L32‧‧‧ slot width

L33‧‧‧ slot width

Y‧‧‧The direction of travel of the conveyor belt

Claims (13)

A labyrinth seal is disposed adjacent to a surface of the traveling body and is disposed on a wind-shielding member that blocks the surface and carries the wind. The labyrinth seal has a first sealing portion formed in the block The wind member has a first groove facing the surface, and the first groove is formed to be long in a direction intersecting the traveling direction of the traveling body, and the first groove is arranged in the traveling direction. And the second sealing portion has a second groove having a groove width or a groove depth different from the first groove, and the second groove is arranged in three or more rows in the traveling direction. The labyrinth seal according to claim 1, wherein the labyrinth seal further includes a third seal portion adjacent to the second seal portion, wherein the third seal portion has a groove width or a groove depth The third groove different from the first groove and the second groove has three or more grooves arranged in the traveling direction. The labyrinth seal according to claim 1 or 2, wherein the groove width and the groove depth are determined in accordance with a frequency band of the air pressure vibration that carries the wind. A casting device comprising: a supporting body for walking; a mold for discharging a dope from the discharge port toward the support body, the mold forming a liquid bead between the mold and the support body, and forming a casting on a surface of the support body a wind-shielding member that blocks the wind carried by the traveling of the support body, wherein the wind-shielding member is closer to the surface of the support body than the liquid bead on the upstream side of the traveling body in the traveling direction of the support bead And the labyrinth seal is disposed on a facing surface of the windshield member facing the support body, the labyrinth seal having a first seal portion and a second seal portion, wherein the first seal portion is formed on The first groove has a first groove, and the first groove is formed to be long in a direction intersecting the traveling direction, and the first groove is divided into three or more in the traveling direction, and the second sealing portion has a groove. The second groove having a width or a groove depth different from the first groove, and the second groove is arranged in three or more in the traveling direction. The casting device according to claim 4, wherein the labyrinth seal has a third sealing portion adjacent to the second sealing portion, and the third portion The sealing portion has a third groove having a groove width or a groove depth different from the first groove and the second groove, and the third groove is arranged in three or more in the traveling direction. The casting apparatus according to Item 4 or 5, wherein the groove width and the groove depth are determined in accordance with a frequency band of the air pressure vibration of the wind. The casting device according to Item 4 or 5, wherein the groove width is 3 mm or more and 30 mm or less, and the groove depth is 1 mm or more and 20 mm or less. The casting device according to claim 6, wherein the groove width is 3 mm or more and 30 mm or less, and the groove depth is 1 mm or more and 20 mm or less. A solution film forming apparatus comprising: a traveling support; a mold that discharges a dope from the discharge port toward the support body, the mold forming a liquid bead between the support and the support body, and forming a flow on a surface of the support body a wind-shielding member that blocks the wind carried by the walking of the support body, wherein the wind-shielding member is closer to the surface of the support body than the liquid droplet on the upstream side of the traveling direction of the support body and along the liquid a labyrinth seal is disposed on a facing surface of the windshield member facing the support body, the labyrinth seal having a first seal portion and a second seal portion, wherein the first seal portion is formed on The first groove has a first groove, and the first groove is formed to be long in a direction intersecting the traveling direction, and the first groove is divided into three or more in the traveling direction, and the second sealing portion has a groove. a second groove having a width or a groove depth different from that of the first groove; the second groove is arranged in three or more rows in the traveling direction; and a drying device that peels the cast film from the support and performs drying . The solution film forming apparatus according to claim 9, wherein the labyrinth seal has a third seal portion adjacent to the second seal portion, and the third seal portion has a groove width or a groove depth and the aforementioned In the third groove different from the first groove and the second groove, the third groove is arranged in three or more in the traveling direction. The solution film forming apparatus according to claim 9 or 10, wherein the groove width and the groove depth are determined in accordance with a frequency band of the air pressure vibration of the wind. The solution film forming apparatus according to claim 9 or 10, wherein the groove width is 3 mm or more and 30 mm or less, and the groove depth is 1 mm or more and 20 mm or less. A solution film forming method comprising the steps of: forming a cast film by using a casting device, wherein the casting device has a support body, a mold, a windshield member, and a labyrinth seal, and the mold is moved from the discharge port toward the front side The support body discharges the dope, the mold forms a liquid bead between the support and the support body, and a casting film is formed on the surface of the support body, and the wind shield member blocks the wind carried by the support body, and the wind shield is blocked. The member is disposed closer to the surface of the support than the liquid droplet on the upstream side of the support body in the traveling direction, and is disposed along the liquid bead, and the labyrinth seal is disposed on the support of the wind shield toward the support The labyrinth seal has a first seal portion and a second seal portion, and the first seal portion is formed on the opposing surface and has a first groove, and the first groove intersects with the traveling direction The first groove is formed in a long direction, and the first groove has three or more grooves arranged in the traveling direction. The second sealing portion has a second groove having a groove width or a groove depth different from the first groove. The second grooves are arranged three or more apart in the traveling direction; and the step of peeling the cast film from the support and drying it.