TWI586512B - Drying apparatus, film drying method, and solution casting method - Google Patents

Description

Drying device, film drying method and solution film forming method

The present invention relates to a drying device, a method for drying a film, and a method for forming a solution.

A translucent polymer film (hereinafter referred to as a film) is lightweight and easy to mold, and thus is widely used as an optical film. In particular, a cellulose ester film such as a cellulose halide is used as a constituent member of a liquid crystal display device which is widely used in the market as a representative of a photo-sensing film, that is, an optical film. Examples of such an optical film include a retardation film, a polarizing plate protective film, and the like.

This film is produced by a solution film forming method. The outline of the solution film forming method is as follows. First, a polymer solution containing a polymer and a solvent (hereinafter referred to as a dope) is discharged, and a cast film is formed on the movable support. Second, the solvent is evaporated from the casting film until the cast film is in a state of being independently transportable. Third, the cast film was peeled off from the moving support as a wet film. Thereafter, the film can be obtained from the wet film by evaporating the solvent from the wet film.

In order to improve the production efficiency in the solution film forming method, it is necessary to efficiently evaporate the solvent in the casting film. For this reason, it is necessary to blow a vertical dry wind to the cast film (hereinafter referred to as a formal drying process). However, if the vertical dry air is blown to the casting film after the formation, wrinkles are generated on the surface of the casting film. Even if the wrinkled cast film is peeled off directly from the support, wrinkles remain on the resulting film.

For example, Japanese Laid-Open Patent Publication No. 2007-290375 proposes a method of effectively drying a cast film while preventing generation of wrinkles. In the drying method described in Japanese Laid-Open Patent Publication No. 2007-290375, a drying duct is provided so as to cover the surface of the casting film with respect to the casting film after the formation, and the relative flow is sent toward the gap between the drying duct and the casting film. The film is formed into a pre-drying wind of the downwind (hereinafter referred to as pre-drying treatment). By performing the pre-drying treatment for a certain period of time, a dry layer having a smooth surface can be formed on the surface side of the cast film. Further, by performing the pre-drying treatment and the main drying treatment in sequence, it is possible to efficiently produce a film having a smooth surface.

In the drying method described in Japanese Laid-Open Patent Publication No. 2007-290375, in order to further improve the production efficiency, it is necessary to increase the moving speed of the moving support. However, when the moving speed of the moving support is increased, the length of the region where the pre-drying treatment is performed (hereinafter referred to as a pre-drying region) must be increased in order to secure the generation time of the dried layer. Therefore, by increasing the wind speed of the pre-drying air as the moving speed of the moving support increases, it is possible to ensure both the generation time of the dried layer and the expansion of the pre-drying area.

However, when the wind speed of the pre-drying wind is increased, a failure occurs in the case where the cast film is to be peeled off from the support, and the cast film remaining on the support or the peeled cast film is torn off.

As a result of intensive research by the inventors, it was found that the above problem is caused by a decrease in drying efficiency in the formal drying treatment. The present invention has been made in an effort to solve such problems, and an object of the invention is to provide a drying apparatus and a method for drying a film which can smoothly dry a cast film even if the surface of the cast film is smooth, and a solution film capable of efficiently producing a film having a smooth surface. method.

The drying device of the present invention is a drying device for drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The drying device includes a cover, a first intake port, a first drying unit, a second intake port, a second drying unit, and a control unit. The aforementioned cover covers the aforementioned film. The first intake air is sent out from the first intake port. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first air inlet sends the first dry air between the outer cover and the film. The first drying unit has the outer cover and the first air inlet. The first drying unit sends the first dry air from the first intake port until a dry layer is formed on the surface side of the film by evaporation of the solvent. The second intake air is sent out from the second intake port. The second intake port is provided on the downstream side of the moving direction of the moving support body than the outer cover. The second intake port sends a substantially vertical second drying wind toward the surface of the film. The second drying unit has the second intake port. The second drying unit promotes evaporation of the solvent by causing the second dry air to collide with the surface of the film. The control unit controls at least one of the wind speed V1 of the first dry air and the wind speed V2 of the second dry air. The control unit controls at least one of the wind speed V1 and the wind speed V2 so as to ensure collision of the second dry air on the surface of the film.

A value of V1/V2 of 0.6 or less is preferable.

It is preferable that the drying device includes an exhaust portion that exhausts the first dry air. The exhaust portion is provided between the outer cover and the second intake port.

The drying device of the present invention is a drying device for drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The drying device includes a cover, a first intake port, a first drying unit, a second intake port, a second drying unit, and an exhaust unit. The aforementioned cover covers the aforementioned film. The first intake air is sent out from the first intake port. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. The first drying unit includes the outer cover and the first air inlet. The first drying unit sends the first dry air from the first intake port until a dry layer is formed on the surface side of the film by evaporation of the solvent. The second intake air is sent out from the second intake port. The second intake port is provided on the downstream side of the moving direction of the moving support body than the outer cover. The second intake port sends a substantially vertical second drying wind toward the surface of the film. The second drying unit has the second intake port. The second drying unit promotes evaporation of the solvent by causing the second dry air to collide with the surface of the film. The exhaust unit exhausts the first dry air. The exhaust portion is provided between the outer cover and the second intake port.

The drying device preferably includes a windshield that blocks the first dry air flowing from the first intake port toward the second intake port.

The drying device of the present invention is a drying device for drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The drying device includes a cover, a first intake port, a first drying unit, a second intake port, a second drying unit, and a windshield. The aforementioned cover covers the aforementioned film. The first intake air is sent out from the first intake port. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. The first drying unit includes the outer cover and the first air inlet. The first drying unit sends the first dry air from the first intake port until a dry layer is formed on the surface side of the film by evaporation of the solvent. The second intake air is sent out from the second intake port. The second intake port is provided on the downstream side of the moving direction of the moving support body than the outer cover. The second intake port sends a substantially vertical second drying wind toward the surface of the film. The second drying unit has the second intake port. The second drying unit promotes evaporation of the solvent by causing the second dry air to collide with the surface of the film. The windshield blocks the first dry air flowing from the first intake port toward the second intake port. The windshield is disposed between the outer cover and the second air inlet.

The method of drying the film of the present invention is a film drying method of drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The method for drying the film includes a first drying step, a second drying step, and a control step. In the first drying step, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. In the second drying step, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. The control step controls at least one of the wind speed V1 of the first dry air and the wind speed V2 of the second dry air. At least one of the wind speed V1 and the wind speed V2 is controlled so as to ensure collision of the second dry wind on the surface of the film.

The method of drying the film of the present invention is a film drying method of drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The film drying method includes a first drying step (A step), a second drying step (B step), and an exhaust step (C step). In the step A, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. In the above step B, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. In the above step C, the first dry air is exhausted. The foregoing exhaust gas is performed between the aforementioned A step and the aforementioned B step.

The method of drying the film of the present invention is a film drying method of drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The method for drying the film includes a first drying step (D step), a second drying step (E step), and a wind shielding step (F step). In the above step D, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. In the above step E, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. In the above step F, the first dry air flowing toward the second intake port is blocked between the step D and the step E.

The solution film forming method of the present invention is a film forming method for producing a film by drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The solution film forming method includes a first drying step (G step), a second drying step (H step), a control step (I step), and a peeling step (J step). In the G step, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. In the above step H, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. In the first step, at least one of the wind speed V1 of the first dry air and the wind speed V2 of the second dry air is controlled. At least one of the wind speed V1 and the wind speed V2 is controlled so as to ensure collision of the second dry wind on the surface of the film. In the above J step, the film after the H step described above is peeled off from the moving support as a film.

The solution film forming method of the present invention is a film forming method for producing a film by drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The solution film forming method includes a first drying step (A step), a second drying step (B step), an exhaust step (C step), and a peeling step (K step). In the above step A, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer periphery and the film. In the above step B, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. In the above step C, the first dry air is exhausted. The foregoing exhaust gas is performed between the aforementioned A step and the aforementioned B step. In the above K step, the film after the step B described above is peeled off from the moving support as a film.

The solution film forming method of the present invention is a film forming method for producing a film by drying a film formed on a moving support. The foregoing film contains a polymer and a solvent. The solution film forming method includes a first drying step (D step), a second drying step (E step), a wind blocking step (F step), and a peeling step (L step). In the above step D, the first dry air is sent from the first intake port of the first drying unit until a dry layer is formed on the surface side of the film by evaporation of the solvent. The first drying unit has a cover and the first intake port. The aforementioned cover covers the aforementioned film. The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover. The first intake port sends a first dry air between the outer cover and the film. In the above step E, evaporation of the solvent is promoted by causing the second dry air from the second drying unit to collide with the surface of the film. The second drying unit has a second intake port. The second intake port sends the second dry air that is substantially perpendicular to the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support. The F step blocks the first dry air flowing toward the second intake port. The aforementioned step F is carried out between the aforementioned step D and the aforementioned step E. In the above-mentioned L step, the film after the step E described above is peeled off from the moving support as a film.

According to the present invention, since the first dry air can be prevented from flowing between the second intake port and the casting film which feed the second dry air toward the casting film, the cast film can be effectively dried. Therefore, according to the present invention, it is possible to prevent malfunction due to insufficient drying of the cast film and to efficiently produce a film having a smooth surface.

(solution film making equipment)

A first embodiment of the present invention will be described. As shown in FIG. 1, the solution film forming apparatus 10 has a casting device 15, a clip tenter 17, a drying device 18, and a winding device 19. The casting device 15 produces the wet film 13 from the dope 12. The clip tenter 17 obtains the film 16 by drying the wet film 13. The drying device 18 performs drying of the wet film 13. The take-up device 19 winds the film 16 around the winding core.

(casting device)

As shown in FIGS. 1 and 2, the casting device 15 has a casing 23 and horizontal rollers 24 and 25 which are arranged substantially horizontally in the casing 23. The horizontal roller 24 is composed of a drive shaft 24a and a roller main body 24b that is axially driven to the drive shaft 24a. The horizontal roller 25 is composed of a shaft 25a and a roller main body 25b that is axially coupled to the shaft 25a. An annular casting belt 26 is wound around the horizontal rolls 24, 25. The casting tape 26 is obtained by joining both ends of the strip-shaped sheet.

The drive shaft 24a is connected to a roller drive motor (not shown). A control unit (not shown) controls the roller drive motor to rotate the horizontal roller 24 at a predetermined speed. The casting belt 26 is cyclically moved in a predetermined direction as the horizontal roller 24 rotates, and the horizontal roller 25 rotates as the casting belt 26 moves. Hereinafter, the moving direction of the casting tape 26 is referred to as the X direction, the width direction of the casting tape 26 is referred to as the Y direction, and the vertical direction is referred to as the Z direction.

The moving speed V _26a of the surface (hereinafter referred to as a casting surface) 26a of the casting belt 26 is preferably 200 m/min or less. If the moving speed V _26a exceeds 200 m/min, it is difficult to stably form the bead. The lower limit of the moving speed V _26a may be considered in consideration of the productivity of the target film. The lower limit of the moving speed V26a is, for example, 10 m/min, that is, the moving speed V _{26a is,} for example, 10 m/min or more.

The casting tape 26 is preferably made of stainless steel, and is more preferably made of SUS316 having sufficient corrosion resistance and strength. The width of the casting belt 26 is preferably, for example, 1.1 times or more and 2.0 times or less the casting width of the dope 12 . The length of the casting belt 26 is preferably 20 m or more and 200 m or less, and the thickness of the casting belt 26 is preferably 0.5 mm or more and 2.5 mm or less. Further, it is preferable to use the casting tape 26 having a thickness unevenness of 0.5% or less with respect to the entire thickness. The casting surface 26a is preferably polished, and the surface roughness of the casting surface 26a is preferably 0.05 μm or less.

Further, in order to set the temperature of the casting surface 26a of the casting belt 26 to a predetermined value, it is preferable to attach a temperature regulating device (not shown) to the horizontal rollers 24 and 25. The surface temperature of the casting belt 26 is preferably a temperature which can be adjusted to 10 ° C to 40 ° C. The temperature regulating device circulates the heat carrier adjusted to a predetermined temperature in the flow path provided in the roller bodies 24b, 25b under the control of the control unit. The temperature of the roller bodies 24b, 25b can be maintained at a predetermined temperature by the circulation of the heat carrier.

In addition, the first to third sealing members 31 to 33 are disposed in this order from the upstream side in the X direction toward the downstream side in the casing 23 . In the casing 23, the first to third sealing members 31 to 33 are partitioned into a casting chamber 23a, a drying chamber 23b, and a separation chamber 23c from the upstream side in the X direction toward the downstream side. Further, the airtightness of the casting chamber 23a is maintained by the first to second sealing members 31 to 32. Further, the airtightness of the drying chamber 23b is maintained by the second to third sealing members 32 to 33.

The first sealing member 31 is composed of a windshield 31a attached to the casing 23 and a labyrinth seal 31b attached to the windshield 31a. The windshield 31a has a windshield that blocks the flow of gas in the casing 23. The windshield may be orthogonal to the X direction or may be obliquely intersected with the X direction. The windshield 31a protrudes from the inner wall surface of the casing 23 and extends toward the casting surface 26a of the casting belt 26. Further, the windshield 31a may be provided so as to protrude from the ceiling.

The labyrinth seal 31b is provided at the front end of the windshield 31a so as to be close to the casting 26a. It is preferable that the labyrinth seal 31b is disposed close to the casting surface 26a of the casting belt 26 which is wound around the horizontal roller 24. The interval between the labyrinth seal 31b and the casting surface 26a is preferably 1.5 mm or more and 2.0 mm or less.

The second sealing member 32 is composed of a windshield 32a attached to the casing 23 and a labyrinth seal 32b attached to the windshield 32a. The windshield 32a has the same shape as the windshield 31a, and protrudes from the ceiling in the casing 23, and extends toward the casting surface 26a of the casting belt 26. The labyrinth seal 32b has the same shape as the labyrinth seal 31b, and is provided at the front end of the windshield 32a so as to be close to the casting surface 26a. It is preferable that the labyrinth seal 32b is disposed close to the casting surface 26a of the casting belt 26 which is wound around the horizontal roller 24. The interval between the labyrinth seal 32b and the casting surface 26a is, for example, 1.0 mm or more and 1.5 mm or less.

The third seal member 33 is composed of a windshield 33a attached to the casing 23 and a labyrinth seal 33b attached to the windshield 33a. The windshield 33a has the same shape as the windshield 31a, and protrudes from the inner wall surface in the casing 23, and extends toward the casting surface 26a of the casting belt 26. The labyrinth seal 33b has the same shape as the labyrinth seal 31b, and is provided at the front end of the windshield 33a so as to be close to the casting surface 26a. The interval between the labyrinth seal 33b and the casting surface 26a is, for example, 1.5 mm or more and 2.0 mm or less.

(casting room)

A casting die 40 and a decompression unit 41 are provided in the casting chamber 23a. The casting die 40 has a dope outlet 40a that flows out of the dope 12, and is disposed above the horizontal roller 24 so that the dope outlet 40a is close to the casting tape 26.

The casting die 40 flows out of the dope 12 from the dope outlet 40a toward the casting belt 26. The dope 12 flowing out of the dope outlet 40a and reaching the casting face 26a forms a bead. The dope 12 reaching the casting surface 26a is cast in the X direction to form a strip-shaped cast film 43.

The decompression unit 41 is a unit for reducing the upstream side of the liquid bead in the X direction, and has a decompression chamber 41a, a decompression fan 41b, and a suction tube 41c. The decompression chamber 41a is disposed on the upstream side in the X direction from the dope outlet 40a of the casting die 40. The decompression fan 41b sucks the gas in the decompression chamber 41a. The suction pipe 41c is connected to the decompression fan 41b and the decompression chamber 41a.

(drying room)

In the drying chamber 23b, the first drying unit 51 to the third drying unit 53 that supply predetermined drying air to the casting film 43 are provided in this order from the upstream side in the X direction to the downstream side. The first drying unit 51 and the second drying unit 52 are disposed above the casting belt 26 that is stretched over the horizontal rollers 24 and 25. The third drying unit 53 is disposed below the casting belt 26 that is stretched over the horizontal rollers 24 and 25.

(first drying unit)

As shown in FIGS. 3 and 4, the first drying unit 51 is composed of a first intake duct 57, a cover 58, a first exhaust duct 59, and a first intake nozzle 60. The first intake duct 57, the outer cover 58, and the first exhaust duct 59 are provided in order from the upstream side in the X direction toward the downstream side. The first intake nozzle 60 is provided in the first intake duct 57.

(first intake duct)

As shown in FIG. 4 and FIG. 5, the first intake duct 57 is a duct through which the first dry air 61 flows, and is disposed closer to the second sealing member 32 in the X direction and away from the casting film 43 in the Z direction. The first intake nozzle 60 is provided on the lower surface 57a of the first intake duct 57, and includes a first intake port 60a that sends out the first dry air 61. The first intake nozzle 60 extends toward the downstream side in the X direction toward the feeding direction of the first dry air 61 . The first intake port 60a opening to the lower surface 57a of the first intake duct 57 is extended from one end of the cast film 43 to the other end.

(1st exhaust duct)

The first exhaust duct 59 is a duct through which the first dry air 61 flows, and is disposed away from the casting film 43 in the Z direction. On the lower surface of the first exhaust duct 59, the first exhaust port 59a that exhausts the first dry air 61 is opened so as to face the casting film 43. The first exhaust port 59a extends from one end of the casting film 43 to the other end.

(cover)

The outer cover 58 guides the first dry air 61 sent from the first air inlet 60a to the first air outlet 59a, and covers the casting film 43 in a state away from the casting film 43 in the Z direction. The outer cover 58 is formed in a plate shape, and is extended from the first intake duct 57 to the first exhaust duct 59 in the X direction, and extends from one end of the cast film 43 to the other end in the Y direction. Below the outer cover 58, there is a guide surface 58a substantially parallel to the casting film 43. The guide surface 58a is preferably on the same horizontal surface as the lower surface 57a of the first intake duct 57 and the lower surface of the first exhaust duct 59.

As shown in FIGS. 4 and 6, the side windshield 65 arranged in the Y direction extends from the first intake duct 57 to the first exhaust duct 59. The side windshield 65 extends from the lower surface 57a or the guide surface 58a toward the casting film 43. It is preferable that the surface 65a on the inner side in the Y direction of the side windshield 65 and the inner surface 60b of the first intake nozzle 60 are on the same horizontal surface. The first air inlet 60a is formed in the first air outlet 59a, and the first air inlet 60a is formed by the guide surface 58a, the lower surface 57a, the casting film 43, and the side windshield 65. The first drying air passage 66 of the wind 61 is dried. The width of the first drying air passage 66 in the Z direction may be determined according to the width W _{43 of the} casting film 43, and is preferably (W _{43 -} 60) mm or more (W ₄₃ -20) mm or less. The length of the first drying air passage 66 in the X direction may be determined according to the manufacturing conditions (moving speed V _{26a of the} casting surface 26a of the casting belt 26, etc.), and is preferably, for example, 2000 mm or more and 3000 mm or less.

(2nd drying unit)

As shown in FIG. 2, a plurality of second drying units 52 are arranged in the X direction. As shown in FIG. 3, the second drying unit 52 is composed of a second intake duct 71, a second exhaust duct 72, and a second intake nozzle 73. As shown in FIG. 4 and FIG. 7, the second intake duct 71 is disposed so as to be separated from the casting film 43 by the second dry air 75. The second intake nozzle 73 provided in the second intake duct 71 extends substantially perpendicularly from the lower surface of the second intake duct 71 toward the casting film 43. As shown in FIG. 4 and FIG. 8, the second intake port 73a that sends out the second dry air 75 is provided at the tip end of the second intake nozzle 73 close to the casting film 43. The interval between the second intake port 73a and the casting film 43 is preferably 100 mm or more and 200 mm or less. The second intake port 73a extends from one end of the casting film 43 to the other end.

The second exhaust duct 72 has a second exhaust port 72a that exhausts the second dry air 75, and is disposed on the downstream side in the X direction from the second intake nozzle 73. The second exhaust port 72a is disposed above the second intake port 73a in the Y direction on the outer side of the second intake port 73a. It is preferable that the second intake port 73a and the second exhaust port 72a are alternately arranged in the X direction.

(3rd drying unit)

As shown in FIG. 2, the third drying unit 53 is composed of a third exhaust duct 81 and a third intake duct 82 which are provided in this order from the upstream side in the X direction toward the downstream side. The third exhaust duct 81 and the third intake duct 82 are disposed apart from each other in the casting belt 26 . The third exhaust duct 81 is provided with a third exhaust port 81a that exhausts the third dry air 84. The third exhaust port 81a opening toward the downstream side in the X direction extends from one end of the casting film 43 to the other end. The third intake port 82a that sends out the third dry air 84 is provided in the third intake duct 82. The third intake port 82a opening toward the upstream side in the X direction extends from one end of the casting film 43 to the other end.

The first to third blowers (not shown) and the first to third temperature adjusters (not shown) are provided in each of the first drying unit 51 to the third drying unit 53. The control unit 85 is connected to the first to third blowers and the first to third temperature controllers. The control unit 85 independently adjusts the temperature or the wind speed of the first dry air 61, the second dry air 75, and the third dry air 84.

(stripping chamber)

A peeling roller 86 is provided in the peeling chamber 23c. The peeling roll 86 peels the cast film 43 which has been peeled off from the casting tape 26 as the wet film 13, and sends the wet film 13 from the exit 23o provided in the peeling chamber 23c.

A condensing device for condensing the solvent contained in the atmosphere in the casing 23 and a recovery device for recovering the condensed solvent may be provided in the casting device 15. Thereby, the concentration of the solvent contained in the atmosphere contained in the casing 23 can be maintained within a constant range.

Referring back to Fig. 1, a plurality of support rollers 87 supporting the wet film 35 are arranged in the transfer portion between the casting device 15 and the clip tenter 17. The support roller 87 rotates around the shaft by a motor (not shown). The support roller 87 supports the wetting film 35 sent from the casting device 15 and guides it to the clip tenter 17. In addition, although FIG. 1 shows the case where two support rollers 87 are arranged in the transfer portion, the present invention is not limited thereto, and one or three or more support rollers 87 may be arranged in the transfer portion. Further, the support roller 87 may be a free roller (non-driven roller, drive roller).

The clip tenter 17 has a plurality of clips that grip both side edges of the wet film 13 in the width direction, and the clip moves on the stretching rail. The wet film 13 held by the clip is sent to the dry air, and the wet film 13 is subjected to a drying process in the width direction.

A trimming device 88 is disposed between the clip tenter 17 and the drying device 18. Both ends of the film 16 fed to the trimming device 88 in the width direction are formed with gripping traces formed by the clips. The trimming device 88 cuts off the ends having the grip marks. The cut portion is sequentially sent to a cutting fan (not shown) and a crusher (not shown) by air supply, and is shredded, and reused as a raw material such as a dope.

The drying device 18 includes a casing having a conveying path of the film 16, a plurality of rollers 18a forming a conveying path of the film 16, and an air conditioner (not shown) for adjusting the temperature or humidity of the atmosphere in the casing. The film 16 introduced into the casing is conveyed while being wound around a plurality of rolls 18a. The residual solvent evaporates from the film 16 transported within the casing by adjustment of the temperature or humidity of the atmosphere. Further, the drying device 18 is connected to an adsorption recovery device (not shown) that recovers the solvent evaporated from the film 16 by adsorption.

A cooling chamber 89, a static eliminating rod (not shown), a knurling applying roller 90, and a trimming device (not shown) are provided between the drying device 18 and the winding device 19 in this order from the upstream side. The cooling chamber 89 cools the film 16 until the temperature of the film 16 becomes approximately room temperature. The static elimination bar performs a static elimination process for removing the film 16 sent from the cooling chamber 89 and charging it. The knurling applying roller 90 applies a knurling for winding to both ends in the width direction of the film 16. The trimming device cuts both ends in the width direction of the film 16 so that knurls are left at both ends in the width direction of the cut film 16.

The take-up device 19 has a pressure roller 19a and a winding core 19b. The film 16 fed to the winding device 19 is wound around the winding core 19b while being pressed by the pressure roller 19a to have a roll shape.

Next, the action of the present invention will be described. As shown in FIG. 2, each of the chambers 23a to 23b having airtightness is formed in the casing 23 by the first to third sealing members 31 to 33. The casting belt 26 passes through the respective chambers 23a to 23c in order.

(casting process)

A casting process in which the casting film 43 composed of the dope 12 is formed on the casting tape 26 is performed in the casting chamber 23a. The casting die 40 continuously flows out of the dope 12 from the dope outlet 40a. The concentrated dope 12 is formed from the casting die 40 over the casting tape 26 to form a bead, and is cast on the casting tape 26. Thus, the casting film 43 composed of the dope 12 is formed on the casting belt 26 (refer to Fig. 9).

Referring back to FIG. 2, the decompression unit 41 can construct a state in which the pressure on the upstream side in the X direction of the liquid droplet is lower than the pressure on the downstream side in the X direction of the liquid droplet. The pressure difference ΔP between the upstream side in the X direction and the downstream side in the X direction of the liquid bead is preferably 10 Pa or more and 2000 Pa or less.

(drying process)

In the drying chamber 23b, a drying process of blowing a predetermined dry air to the casting film 43 and evaporating the solvent from the casting film 43 is performed. The drying process is carried out until the casting film 43 is in a state of being independently transportable. In the drying process, the first drying process, the second drying process, and the third drying process are sequentially performed.

(1st drying process)

In the first drying process, the solvent is evaporated from the casting film 43 until the dry layer 43a is formed on the surface layer of the casting film 43 (refer to FIG. 10). As shown in FIG. 5, the first drying unit 51 sends out the first dry air 61 from the first intake port 60a. The angle θ1 between the direction of the first dry air 61 sent from the first intake port 60a and the Z1 direction is preferably 30° or more and 60° or less, and more preferably 45°. The first dry air 61 sent from the first intake port 60a is led to the first exhaust port 59a by the outer cover 58. Further, the first dry air 61 is exhausted from the first exhaust port 59a.

The wind speed near the surface of the casting film 43 can be increased by the cover 58 close to the casting film 43, and the evaporation of the solvent from the surface of the casting film 43 can be promoted. Further, since the guide surface 58a rectifies the first dry air 61, it has an effect of suppressing the dry spots of the casting film 43. By this first drying process, the casting film 43 becomes a film having the dry layer 43a and the wetting layer 43b (refer to FIG. 10). The dried layer 43a is a portion which is formed on the surface side of the casting film 43 and which is further dried than the wet layer 43b located on the side of the casting tape 26 than the dried layer 43a. Therefore, the solvent content of the dried layer 43a is lower than that of the wet layer 43b. In addition, the surface of the dry layer 43a is smoothly formed. When the casting film 43 which is a film having the dry layer 43a is subjected to a predetermined drying process, the surface of the dried layer 43a becomes the surface of the obtained casting film 43. Therefore, the cast film 43 having a smooth surface can be obtained by forming the dry layer 43a in the casting film 43 after the formation.

Here, the solvent content is the amount of the solvent contained in the cast film or each film as a dry amount standard, a sample is taken from the target film, the mass of the sample is set to x, and the mass after drying the sample is set to y. The time is expressed as {(xy)/y}×100.

The casting film 43 in which the content of the solvent is from 250% by mass to 400% by mass in the first drying process is preferably carried out, and the casting film 43 having a solvent content of 300% by mass or more and 350% by mass or less is more preferably carried out. The temperature of the first dry air 61 is preferably 30° C. or higher and 80° C. or lower. Further, the wind speed of the first dry air 61 is preferably 5 m/sec or more and 25 m/sec or less.

(2nd drying process)

As shown in FIG. 8, in the second drying process, the solvent is evaporated from the casting film 43 by the second dry air 75. The second intake nozzle 73 vertically blows the second dry air 75 to the casting film 43. As a result, when the second dry air 75 comes into contact with the surface of the casting film 43, the stagnation point P is generated in the vicinity of the surface side of the casting film 43 by the branch of the second dry air 75.

As a method of determining whether or not the stagnation point P is formed in the vicinity of the surface side of the casting film 43, when the wind direction is observed in the vicinity of the surface side of the casting film 43, the stagnation point P can be determined.

In the stagnation point P, the thermal energy of the second dry air 75 is easily transmitted to the casting film 43. Thus, the solvent evaporates in the casting film 43 by the contact with the second dry air 75. The second film drying process is preferably carried out with respect to the casting film 43 having a solvent content of 150% by mass or more and 300% by mass or less. The temperature of the second dry air 75 is preferably 30 ° C or more and 80 ° C or less. Further, the wind speed of the second dry air 75 is preferably 5 m/sec or more and 25 m/sec or less.

(3rd drying process)

In the third drying process, the solvent is evaporated from the casting film 43 by the third dry air 84 until it is independently transportable (refer to FIG. 2). The third drying unit 53 flows out of the third dry air 84 from the downstream side in the X direction toward the upstream side along the surface of the casting film 43. As described above, by flowing the third dry air 84 in the opposite direction to the X direction, evaporation of the solvent can be promoted compared to when flowing in the X direction. The third film drying process is preferably carried out with respect to the casting film 43 having a solvent content of 20% by mass or more and 150% by mass or less. The temperature of the third dry air 84 is preferably 40° C. or higher and 80° C. or lower. Further, the wind speed of the third dry air 84 is preferably 5 m/sec or more and 20 m/sec or less.

(peeling process)

In the peeling chamber 23c, a peeling process in which the casting film 43 which has been peeled off from the casting tape 26 is peeled off is performed. The peeling roll 86 peels the cast film 43 which has been peeled off from the casting tape 26 as the wet film 13, and sends the wet film 13 from the exit 23o provided in the peeling chamber 23c. The casting process is preferably carried out with respect to the casting film 43 having a solvent content of 20% by mass or more and 80% by mass or less.

When returning to the first drying process, when the speed of the first dry air 61 is increased, the first dry air 61 flows between the second intake nozzle 73 and the casting film 43. The second dry air 75 is extruded toward the downstream side in the X direction by the first dry air 61. As a result, in the second drying process, the second dry air 75 does not come into contact with the casting film 43. Therefore, as shown in FIG. 11, the stagnation point P regarding the second dry air 75 is not generated. In addition, the first dry air 61 that is in contact with the casting film 43 in the second drying process has a lower drying ability than the second dry air 75. At this time, the drying efficiency in the second drying process is lowered.

In the present invention, the first drying unit 51 exhausts the first dry air 61 from the first exhaust port 59a. Therefore, the first dry air 61 can be prevented from flowing between the second intake nozzle 73 and the casting film 43. Therefore, according to the present invention, the surface of the casting film 43 can be made smoother while the casting film 43 can be effectively dried. Further, according to the solution film forming method for performing such a drying process, the film 16 having a smooth surface can be efficiently produced (refer to Fig. 1).

Next, a second embodiment of the present invention will be described. As shown in FIG. 12, the first drying unit 51 is composed of a first intake duct 57, a cover 58, and a first rectifying plate 94 which are provided in this order from the upstream side toward the downstream side in the X direction.

The first rectifying plate 94 extending from one end of the casting film 43 to the other end is disposed to be erected with respect to the casting film 43. The lower end 94b of the first flow regulating plate 94 is close to the casting film 43, and the upper end 94a of the first flow regulating plate 94 extends above the second intake port 73a. The first rectifying plate 94 can prevent the first dry air 61 from flowing between the second intake nozzle 73 and the casting film 43.

Further, the upper exhaust duct 95 provided above the first rectifying plate 94 can be added to the first drying unit 51. The upper exhaust duct 95 includes an upper exhaust port 95a that exhausts the first dry air 61. The upper end 94a of the first flow regulating plate 94 is preferably extended toward the upper exhaust port 95a. Further, the first wind-shielding member 96 having the same configuration as that of the first sealing member 31 can be provided between the first drying unit 51 and the second drying unit 52.

Further, it is preferable that the lower end 94b of the first flow regulating plate 94 extends to the downstream portion of the first drying air passage 66 in the X direction. As shown, the first rectifying plate 94 may be a flat plate in addition to the curved plate, or may be a combination of a curved plate and a flat plate, a combination of a plurality of curved plates, and a combination of a plurality of flat plates. It is also possible to combine a plurality of flat plates or a combination of a flat plate and a curved plate. Further, in order to secure the maintenance at the time of stop of the flow, the first rectifying plate 94 is movable in a direction away from the casting belt 26 by an operation from the outside of the casing 23.

In addition, an anemometer of each dry air is provided in each of the first drying unit 51 and the second drying unit 52, and the balance between the first dry air 61 and the second dry air 75 is adjusted so that the first dry air 61 is in the first The dynamic pressure in the drying unit 51 becomes smaller than the dynamic pressure of the second drying air 75 in the second drying unit 52. Here, the "dynamic pressure of the first dry air 61 in the first drying unit 51" is the dynamic pressure between the outer cover 58 and the casting film 43 in the first dry air 61 (the first dry air 61x in the drawing). In addition, when the side air deflector 65 is provided, the "dynamic pressure of the first dry air 61 in the first drying unit 51" can be set as the dynamic pressure of the first dry air 61 in the first intake nozzle 60. The dynamic pressure of the second drying air 75 in the second drying unit 52 is the dynamic pressure of the second dry air 75 between the second intake nozzle 73 and the casting film 43.

In order to adjust the magnitude relationship between the dynamic pressure of the first dry air 61 and the dynamic pressure of the second dry air 75, the first anemometer 101 (refer to FIG. 5) and the second anemometer 102 (refer to FIG. 8) may be provided. The first anemometer 101 that measures the wind speed V ₆₁ of the first dry air 61 can be installed in the first intake nozzle 60 as shown in FIG. 5 or can be converted from the internal pressure of the first intake duct 57 into The wind speed may be provided in a duct disposed between the first intake duct 57 and the first blower fan, and may be converted based on the measured air volume. The measurement of the speed V ₇₅ of the second dry air 75 can measure the internal pressure of the second intake nozzle 73 and convert it into a wind speed, and can also be disposed in the duct between the second intake duct 71 and the second blower fan. Set the air flow meter and convert it according to the measured air volume (refer to Figure 8). The control unit 85 reads the speeds V ₆₁ and V ₇₅ from the first anemometer 101 and the second anemometer 102, respectively. Then, the control unit 85 controls the number of rotations of at least one of the first to second blowers based on the read speeds V ₆₁ and V ₇₅ so that the value of (V ₆₁ /V ₇₅ ) is 0.6 or less. In this way, it is possible to prevent the second dry air 75 from being rushed to the downstream side in the X direction by the first dry air 61 (refer to FIG. 11).

Moreover, the control unit 85 can control the number of rotations of at least one of the first to second blowers in order to prevent the first dry air 61 from flowing back in the X direction. In order to prevent backflow of the first dry air 61, the speed V ₆₁ is 20 m/sec or less and the value of (V ₆₁ /V ₇₅ ) is preferably 0.2 or more and 0.85 or less.

When the rotation speeds of the first to second blower fans are controlled as described above, the first exhaust duct 59 (refer to FIG. 5) in the first embodiment or the rectifying plate 90 and the upper row in the second embodiment can be omitted. Air duct 95 and windshield seal 92 (refer to Figure 12).

Further, a wind deflector 105 (refer to FIG. 5) may be provided between the first intake duct 57 and the second seal member 32. The windshield 105 is disposed in a posture in which the casting film 43 is erected. The lower end 105a of the windshield 105 protrudes toward the casting film 43 side from the lower surface 57a of the first intake duct 57. The backflow of the first dry air 61 can be prevented by the windshield 105.

The installation position of the casting die 40 is set to be above the horizontal roller 24, but the present invention is not limited thereto. When the sealing members 31 to 32 are disposed close to the portion wound by the casting belt 26 of the horizontal roller 25, the installation position of the casting die 40 can be set as the upper side of the horizontal roller 24. Further, when the support roller supporting the casting tape 26 is disposed between the horizontal rollers 24, 25, and the sealing members 31 to 32 are disposed close to the portion of the casting tape 26 supported by the support roller, the casting die can be used. The setting position of 40 is set to be above the support roller.

The film 16 obtained by the present invention can be especially used for a retardation film or a polarizing plate protective film.

The width of the film 16 is preferably 600 mm or more, more preferably 1400 mm or more and 2500 mm or less. Moreover, the present invention is also effective when the width of the film 16 is greater than 2,500 mm. Further, the film thickness of the film 16 is preferably 30 μm or more and 120 μm or less.

Further, the in-plane retardation Re of the film 16 is preferably 20 nm or more and 300 nm or less, and the thickness of the film 16 is preferably -100 nm or more and 300 nm or less in retardation Rth.

The method of measuring the in-plane retardation Re is as follows. The in-plane retardation Re was measured by using an automatic birefringence meter (KOBRA 21DH Prince Metering Equipment Co., Ltd.) from the vertical direction of 632.8 nm using a humidity measurement at a temperature of 25 ° C and a humidity of 60% RH for 2 hours. In addition, Re is expressed by the following formula.

Re=∣n1-n2∣×d

N1 represents the refractive index of the slow axis, n2 represents the refractive index of the phase axis 2, and d represents the thickness (film thickness) of the film.

The method of measuring the thickness direction retardation Rth is as follows. The sample film was conditioned for 2 hours at a temperature of 25 ° C and a humidity of 60% RH, and the value measured from the vertical direction of 632.8 nm was measured by an ellipsometer (M150 Japan Spectrophotogene Co., Ltd.) and the film side was inclined. The extrapolated value of the measured delay value is calculated according to the following formula.

Rth={(n1+n2)/2-n3}×d

N3 represents the refractive index in the thickness direction.

(polymer)

In the above embodiment, the polymer which is a raw material of the polymer film is not particularly limited, and examples thereof include cellulose halides and cyclic polyolefins.

(cellulose cellulose)

The thiol group used for the cellulose halide of the present invention may be used alone or two or more kinds of fluorenyl groups may be used. When two or more kinds of mercapto groups are used, one of them is preferably an ethylidene group. The ratio of the esterification of the hydroxyl group in the cellulose with a carboxylic acid, 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 to 4 mm.

(I) 2.0 A+B 3.0

(II) 1.0 A 3.0

(III)0 B 2.0

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 thiol group having 3 to 22 carbon atoms is more preferably 0.30 or more, and particularly preferably 0.5 or more.

The cellulose which is a raw material of the cellulose halide may be cellulose obtained from any one of cotton wool fibers and pulp.

The fluorenyl group having 2 or more carbon atoms of the cellulose halide of the present invention may be an aliphatic group or an aryl group, and is not particularly limited. These may, for example, be an alkylcarbonyl ester of cellulose, an olefinic carbonyl ester or an aromatic carbonyl ester, an aromatic alkylcarbonyl ester or the like, and may each have a further substituted group. As preferred examples thereof, a propyl group, a butyl group, a pentyl group, a hexyl group, a octyl group, a decyl group, a dodecyl group, a tridecyl fluorenyl group, a tetradecyl fluorenyl group, and a hexadecane group can be cited. An alkanoyl group, an octadecyl fluorenyl group, an isobutyl fluorenyl group, a tertiary butyl group, a cyclohexanecarbonyl group, an oil sulfhydryl group, a benzamyl group, a naphthylcarbonyl group, a cinnamyl group, and the like. Among them, a propyl fluorenyl group, a butyl decyl group, a dodecyl fluorenyl group, an octadecyl fluorenyl group, a tertiary butyl fluorenyl group, an oil fluorenyl group, a benzamidine group, a naphthylcarbonyl group and a cinnamyl group are more preferably a propyl sulfonyl group or a butyl fluorenyl group. Especially good.

(solvent)

Examples of the solvent for preparing the dope include aromatic hydrocarbons (for example, benzene and toluene), halogenated hydrocarbons (for example, dichloromethane and chlorobenzene, etc.), and alcohols (for example, methanol, ethanol, n-propanol, and n-butylene). Alcohol and diethylene glycol, etc., ketones (for example, acetone and methyl ethyl ketone), esters (for example, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (for example, tetrahydrofuran, methyl cellosolve, etc.) . Further, in the present invention, the dope refers to a polymer solution or a dispersion obtained by dissolving or dispersing a polymer in a solvent.

Among these, a halogenated hydrocarbon having 1 to 7 carbon atoms is preferably used, and dichloromethane is most preferred. From the viewpoint of the solubility of the polymer, the peelability of the cast film from the support, the mechanical strength of the film, and the optical properties of the film, etc., one to several carbon atoms are mixed in addition to methylene chloride. An alcohol of ～5 is preferred. The content of the alcohol is preferably 2% by mass to 25% by mass based on the total amount of the solvent, and more preferably 5% by mass to 20% by mass. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, and the like, but methanol, ethanol, n-butanol or a mixture thereof is preferably used.

However, in order to minimize the influence on the environment, the solvent composition when dichloromethane is not used has been studied. For this purpose, an ether having 4 to 12 carbon atoms and a carbon number are used. The ketone of 3 to 12, the ester having 3 to 12 carbon atoms, and the alcohol having 1 to 12 carbon atoms are preferred. Sometimes these are mixed as appropriate. For example, a mixed solvent of methyl acetate, acetone, ethanol, and n-butanol can be mentioned. These ethers, ketones, esters and alcohols may have a cyclic structure. Further, any one of a functional group having two or more ethers, a ketone, an ester, and an alcohol (that is, -O-, -CO-, -COO-, and -OH) can also be used as a solvent.

Further, the details of the cellulose halide 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. Further, in the paragraphs [0196] to [0516] of Japanese Patent Laid-Open Publication No. 2005-104148, solvents and plasticizers, deterioration inhibitors, ultraviolet absorbers (UV agents), optical anisotropy control agents, and retardation inhibition are also known. Additives such as agents, dyes, matting agents, release agents, and release accelerators are described in detail.

In the above embodiment, the cast film is formed by the present invention, but the present invention is not limited thereto, and may be applied to a case where a coating liquid is applied onto a support and a coating film is formed on the support. That is, according to the present invention, it is possible to effectively form a coating film having a smooth surface.

[Examples]

(Experiment 1)

The film 16 is produced in the solution film forming apparatus 10 shown in FIG. In the casting device 15, the casting process, the drying process, and the stripping process are sequentially performed. The first drying process, the second drying process, and the third drying process are sequentially performed in the drying process. The first drying process, the blowing wind speed V ₆₁ 43 1 drying air to the casting film 61. Second drying process, the wind speed V ₇₅ is blown to the casting film 43 second drying wind 75.

(Experiment 2 to 25)

The film 16 was produced in the same manner as in Experiment 1 except that the wind speed V ₆₁ and the wind speed V _{75 were} adjusted to the values shown in Table 1.

(Evaluation)

Regarding the film 16 obtained in Experiments 1 to 25, the following items were evaluated.

1. Stripability evaluation

The peeling property of the cast film was performed based on the following criteria.

A: The entire cast film can be peeled off from the casting tape.

B: A part of the cast film remains on the support.

2. Face evaluation

The surface shape of the cast film was visually observed and carried out according to the following criteria.

A: The film surface is smooth.

B: Small unevenness appeared on the surface of the film.

3. Evaluation of the first dry wind countercurrent

The pressure P1 between the wind deflector 105 (refer to FIG. 5) and the casting film 43 and the pressure P2 in the casting chamber 23a were measured by a pressure gauge. The pressure P2 is measured by disposing the open end of the hose connected to the pressure gauge between the windshield 105 (refer to FIG. 5) and the casting film 43. Further, the pressure from the pressure P2 minus the pressure P1 is set as the dynamic pressure.

A: The dynamic pressure obtained is less than 1.0 Pa.

B: The dynamic pressure obtained is 1.0 Pa or more.

In any of the above 1 to 3, A was acceptable, and B was unacceptable.

The values of V ₆₁ , V ₇₅ and (V ₆₁ /V ₇₅ ) in Experiments 1 to 25 and the above evaluation results are shown in Table 1. Further, the number added to the evaluation result of Table 1 indicates the number added to the above evaluation item.

10. . . Solution film making equipment

12. . . Concentrate

13. . . Wet film

15. . . Casting device

16. . . membrane

17. . . Clip tenter

18. . . Drying device

18a. . . Roll

19. . . Winding device

19a. . . Pressure roller

19b. . . Core

twenty three. . . case

23a, 23b, 23c. . . room

23o. . . Export

24, 25. . . Horizontal roller

24a. . . Drive shaft

24b, 25b. . . Roller body

25a. . . axis

26. . . Casting zone

26a. . . Casting surface

31. . . First sealing member

31a, 32a, 33a, 105. . . windshield

31b, 32b, 33b. . . Labyrinth seal

32. . . Second sealing member

33. . . Third sealing member

40. . . Casting die

40a. . . Concentrated liquid outlet

41. . . Decompression unit

41a. . . Decompression chamber

41b. . . Pressure reducing fan

41c. . . Suction tube

43. . . Cast film

43a. . . Dry layer

43b. . . Wet layer

51. . . First drying unit

52. . . Second drying unit

57. . . First intake duct

57a. . . Below the first intake duct 57

58. . . Cover

58a. . . Guide surface

59. . . First exhaust duct

59a. . . First exhaust port

60. . . First intake nozzle

60a. . . First air inlet

60b. . . Inner surface of the first intake nozzle 60

61, 61x. . . First dry wind

65. . . Side windshield

65a. . . The inner side surface of the side windshield 65 in the Y direction

66. . . First dry air path

71. . . Second intake duct

72. . . Second exhaust duct

72a. . . Second exhaust port

73. . . Second intake nozzle

73a. . . Second air inlet

75. . . Second dry wind

81. . . Third exhaust duct

81a. . . Third exhaust port

82. . . Third intake duct

82a. . . Third air inlet

84. . . Third dry wind

85. . . Control department

86. . . Stripping roller

87. . . Support roller

88. . . Trimming device

89. . . Cooling room

90. . . Knurling roller

94. . . First rectifying plate

94a. . . First rectifying plate

94b. . . The lower end of the first rectifying plate 94

95. . . Upper exhaust duct

95a. . . Upper exhaust port

96. . . First windshield sealing member

101. . . 1st anemometer

102. . . 2nd anemometer

105a. . . Lower end of the windshield 105

P. . . Stagnation point

X, Y, Z. . . direction

Θ1. . . angle

Fig. 1 is an explanatory view showing an outline of a solution film forming apparatus.

Fig. 2 is an explanatory view showing an outline of a casting device.

3 is a perspective view showing an outline of a first drying unit and a second drying unit.

4 is an explanatory view showing an outline of a first drying unit and a second drying unit.

Fig. 5 is a cross-sectional view taken along line V-V of Fig. 4 showing an outline of a first drying unit.

Fig. 6 is a cross-sectional view taken along line VI-VI of Fig. 4 showing an outline of the first drying unit.

Fig. 7 is a perspective view showing an outline of a second intake duct and a second intake nozzle.

Fig. 8 is a side view showing an outline of a second drying unit.

Fig. 9 is a cross-sectional view showing an outline of a cast film after formation.

Fig. 10 is a cross-sectional view showing an outline of a cast film having a dry layer.

Fig. 11 is an explanatory view schematically showing a state in which the second dry air is extruded by the first dry air.

FIG. 12 is an explanatory view showing an outline of a first drying unit and a second drying unit.

26. . . Casting zone

32. . . Second sealing member

43. . . Cast film

51. . . First drying unit

52. . . Second drying unit

57. . . First intake duct

58. . . Cover

58a. . . Guide surface

60. . . First intake nozzle

61. . . First dry wind

65. . . Side windshield

71. . . Second intake duct

72. . . Second exhaust duct

73. . . Second intake nozzle

73a. . . Second air inlet

75. . . Second dry wind

94. . . First rectifying plate

94a. . . First rectifying plate

94b. . . The lower end of the first rectifying plate 94

95. . . Upper exhaust duct

95a. . . Upper exhaust port

96. . . First windshield sealing member

101. . . 1st anemometer

102. . . 2nd anemometer

105. . . windshield

P. . . Stagnation point

Claims (12)

A drying device for drying a film comprising a polymer and a solvent formed on a moving support, wherein the drying device comprises: a cover covering the film; and a first air inlet for sending the first dry air, The first intake port is provided on the upstream side of the moving direction of the moving support body than the outer cover, and the first intake port sends the first dry air between the outer cover and the film; the first drying unit; The first outer drying unit and the first air inlet, the first drying unit sends the first dry air from the first air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent; the second air intake The second dry air is sent to the port, and the second air inlet is provided on the downstream side of the moving direction of the moving support body, and the second air inlet is sent to the surface of the film to be substantially perpendicular to the second side. a second drying unit having the second air inlet, wherein the second drying unit accelerates evaporation of the solvent by causing the second dry air to collide with a surface of the film; and a control unit controls At least one of the wind speed V1 of the first dry air and the wind speed V2 of the second dry air, the control unit controls the wind speed V1 and the wind speed V2 so as to ensure a collision of the second dry air against the surface of the film. At least either side. The drying apparatus according to claim 1, wherein the value of V1/V2 is 0.6 or less. The drying device according to claim 1, further comprising: an exhaust unit that exhausts the first dry air, wherein the exhaust unit is provided between the outer cover and the second intake port . A drying device for drying a film comprising a polymer and a solvent formed on a moving support, wherein the drying device comprises: a cover covering the film; and a first air inlet for sending the first dry air, The first intake port is provided on an upstream side of the moving direction of the moving support body than the outer cover, and the first intake port sends a first dry air between the outer cover and the film; and the first drying unit The first outer drying unit and the first air inlet, the first drying unit sends the first dry air from the first air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent; the second air inlet And sending the second dry air, wherein the second air inlet is provided on a downstream side of the moving direction of the moving support body, and the second air inlet sends a substantially vertical second drying toward the surface of the film. a second drying unit having the second air inlet, wherein the second drying unit promotes evaporation of the solvent by causing the second dry air to collide with a surface of the film; and an exhaust unit 1 Dry exhaust air, the exhaust portion is provided between the housing and the second intake port. The drying device according to claim 1, further comprising: a windshield that blocks the first dry air flowing from the first intake port toward the second intake port. A drying device for drying a film comprising a polymer and a solvent formed on a moving support, wherein the drying device comprises: a cover covering the film; and a first air inlet for sending the first dry air, The first intake port is provided on an upstream side of the moving direction of the moving support body than the outer cover, and the first intake port sends a first dry air between the outer cover and the film; and the first drying unit The first outer drying unit and the first air inlet, the first drying unit sends the first dry air from the first air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent; the second air intake The second dry air is sent to the port, and the second air inlet is provided on the downstream side of the moving direction of the moving support body, and the second air inlet is sent to the surface of the film to be substantially perpendicular to the second side. a second drying unit having the second air inlet, wherein the second drying unit promotes evaporation of the solvent by causing the second dry air to collide with a surface of the film; and a windshield to block The first air blower flows toward the first air inlet, and the wind deflector is provided between the outer cover and the second air inlet. A method for drying a film, which comprises drying a film comprising a polymer and a solvent on a moving support, wherein the method for drying the film comprises the step of: delivering the first from the first inlet of the first drying unit Drying the wind until a drying layer is formed on the surface side of the film by evaporation of the solvent, the first drying unit has a cover and the first air inlet, and the cover covers the film, and the first air inlet is more than the outer cover Provided on the upstream side in the moving direction of the moving support body, the first intake port sends a first dry air between the outer cover and the film; and the second dry air from the second drying unit and the film The surface collision causes evaporation of the solvent, and the second drying unit has a second intake port, and the second intake port sends the second dry air that is substantially perpendicular to the surface of the film, and the second air inlet is At least one of the second dry air is sent downstream of the moving cover in the moving direction of the moving support; and at least one of the wind speed V1 of the first dry air and the wind speed V2 of the second dry air is controlled. At least one of the wind speed V1 and the wind speed V2 is controlled so as to ensure collision of the second dry wind on the surface of the film. A film drying method for drying a film comprising a polymer and a solvent formed on a movable support, characterized in that the film drying method comprises the following steps: (A) a first air inlet from the first drying unit The first dry air is sent until a drying layer is formed on the surface side of the film by evaporation of the solvent, the first drying unit has a cover and the first air inlet, and the outer cover covers the film, and the first air inlet ratio The outer cover is provided on the upstream side in the moving direction of the moving support body, and the first intake port sends the first dry air between the outer cover and the film; (B) the second drying unit is provided (2) the drying air collides with the surface of the film to promote evaporation of the solvent, the second drying unit has a second air inlet, and the second air inlet sends a substantially vertical second drying air toward the surface of the film. The second intake port sends the second dry air downstream of the outer cover in a moving direction of the moving support; and (C) exhausts the first dry air, and the exhaust is in the step A and Step B above Between the steps. A method for drying a film, which comprises drying a film comprising a polymer and a solvent on a moving support, wherein the method for drying the film comprises the steps of: (D) a first air inlet from the first drying unit The first dry air is sent until a drying layer is formed on the surface side of the film by evaporation of the solvent, the first drying unit has a cover and the first air inlet, and the outer cover covers the film, and the first air inlet ratio The outer cover is provided on the upstream side in the moving direction of the moving support body, and the first intake port sends the first dry air between the outer cover and the film; (E) the second drying unit is provided (2) the drying air collides with the surface of the film to promote evaporation of the solvent, the second drying unit has a second air inlet, and the second air inlet sends a substantially vertical second drying air toward the surface of the film. The second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support; and (F) blocks the second intake port between the step D and the step E Flowing The first dry wind mentioned above. A solution film forming method for drying a film comprising a polymer and a solvent formed on a moving support to produce a film, wherein the solution film forming method comprises the following steps: (G) the first step from the first drying unit The first dry air is sent to the air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent, and the first drying unit has a cover and the first air inlet, and the outer cover covers the film, and the first The air port is provided on the upstream side of the moving direction of the moving support body than the outer cover, and the first air inlet port sends the first dry air between the outer cover and the film; (H) is caused by the second drying The second dry air of the unit collides with the surface of the film to promote evaporation of the solvent, the second drying unit has a second air inlet, and the second air inlet sends the second drying that is substantially perpendicular to the surface of the film. In the wind, the second intake port sends the second dry air downstream of the outer cover in the moving direction of the moving support; (I) controlling the wind speed V1 of the first dry air and the second dry wind Wind speed V2 At least one of the wind speed V1 and the wind speed V2 is controlled so as to ensure collision of the second dry wind on the surface of the film; and (J) after peeling off the H step from the moving support The aforementioned film serves as a film. A solution film forming method for drying a film comprising a polymer and a solvent formed on a movable support to produce a film, wherein the solution film forming method comprises the following steps: (A) the first step from the first drying unit The first dry air is sent to the air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent, and the first drying unit has a cover and the first air inlet, and the outer cover covers the film, and the first The air port is provided on the upstream side of the moving direction of the moving support body, and the first air inlet port sends the first dry air between the outer cover and the film; (B) the second drying is performed. The second dry air of the unit collides with the surface of the film to promote evaporation of the solvent, the second drying unit has a second air inlet, and the second air inlet sends the second drying that is substantially perpendicular to the surface of the film. In the wind, the second intake port sends the second dry air downstream of the outer cover in a moving direction of the moving support; (C) exhausts the first dry air, and the exhaust gas is in the A Steps and Carried out between the step B above; and (K) after the film is peeled from the previous step B moving support as a film. A solution film forming method for drying a film comprising a polymer and a solvent formed on a moving support to produce a film, wherein the solution film forming method comprises the following steps: (D) the first step from the first drying unit The first dry air is sent to the air inlet until a dry layer is formed on the surface side of the film by evaporation of the solvent, and the first drying unit has a cover and the first air inlet, and the outer cover covers the film, and the first The air port is provided on the upstream side of the moving direction of the moving support body, and the first air inlet port sends the first dry air between the outer cover and the film; (E) the second drying is performed. The second dry air of the unit collides with the surface of the film to promote evaporation of the solvent, the second drying unit has a second air inlet, and the second air inlet sends the second drying that is substantially perpendicular to the surface of the film. In the wind, the second intake port sends the second dry air downstream of the moving cover in the moving direction of the moving support; (F) blocks the second forward between the D step and the E step. Air port The first dry air flowing; and (L) the film after the step E is peeled off from the moving support as a film.