JP6588364B2 - Solution casting apparatus and solution casting method - Google Patents

Description

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

  A solution casting method is known as a method for producing a film for optical use. A solution casting method for producing a long film is a method in which a casting film is formed on a support by flowing out from a die toward a support running a dope in which a polymer is dissolved in a solvent. This is a production method in which the membrane is peeled off from the support and dried. The cast film may be dried on the support so that it can be transported by a roller or the like after being peeled off from the support. And in order to express the target optical performance or improve the mechanical properties, the film formed by peeling off from the support is stretched in the width direction by a stretching device called a tenter. Usually applied.

  The tenter stretches the film in the width direction by holding the side end of the long film by the holding member and moving the holding member in the width direction while moving in the film transport direction. When the cast film is peeled off after drying on the support, a clip is used as the holding member, and the side end of the film is held by the clip.

  By the way, the film guided by the tenter may have a thicker side end gripped by the clip than a central portion between one side end and the other side end. For example, a bead formed of a dope from a die to a support is pulled in the traveling direction by the traveling support, whereby both side edges are pulled toward the center in the width direction, and the side end is thicker than the center. This phenomenon is called necking. In recent years, there has been a demand for further thinning of the optical film, and in order to prevent tearing by gripping with a clip, the side end portion may be formed intentionally thicker than the central portion (for example, , See Patent Document 1).

  In order to improve productivity, it is necessary to increase the running speed of the support.However, the higher the running speed of the support, the lower the degree of drying of the cast film during stripping. It will be guided to the tenter in a soft state. As the side end portion is thicker as described above, the clip is guided to the clip in a state of low drying, cannot withstand gripping of the clip, and the film may break in the gripping region gripped by the clip. In order to avoid such a phenomenon, there is a technique of increasing the drying conditions on the support, specifically, drying the cast film with a dry gas at a higher temperature. However, with this technique, there is a concern that the cast film may be foamed due to a rapid temperature rise, and the concern increases as the film having a thinner thickness is manufactured. There is also a method of proceeding drying under different conditions for the side edge and the center of the film guided to the tenter. For example, a gas whose temperature is adjusted is blown to a film formed by peeling off, and the film is dried by setting the gas blown to the side end portion and the gas blown to the central portion to different temperatures (for example, Patent Document 2, 3).

JP 2014-148125 A JP 2005-161619 A JP 2005-271233 A

  In a so-called transition part from the support to the tenter, the film is supported by a roller, and tension is applied in the longitudinal direction in order to stably transport the film. In this transition, the film depends on the meandering of the support on the upstream side, the difference in the degree of drying between the one and the other in the width direction of the film at the time of peeling, and the drive unevenness in the tenter on the downstream side. Meanders. Due to this meandering, there is a problem in the tenter that the film is not gripped by the clip, or the gripping region gripped by the clip is shifted in the width direction of the film. This problem becomes more prominent by increasing the running speed of the support or by making the film thinner. When the gripping area is shifted in the width direction of the film, the area in the width direction where the optical performance is constant is shifted in the longitudinal direction, leading to the widening of the cut part on the side, and as a result The product yield is reduced. The methods disclosed in Patent Documents 2 and 3 have a certain effect in stabilizing the conveyance of the film in the transition portion. However, even when the running speed of the support is increased, or when a film having a thinner thickness is manufactured, a method for further widening the width of the product by making the tenter clip more stable is desired. .

  Accordingly, an object of the present invention is to provide a solution casting apparatus and a solution casting method that further stabilize the conveyance of a tenter with a clip and widen a product collection width.

The solution casting apparatus of the present invention includes a dryer, a stretching device, and a cooling device, and continuously forms a casting film from a dope in which a polymer is dissolved in a solvent on a traveling support. A film is formed by peeling off the cast film, and the film is dried. The dryer dries the cast film. The stretching device has a gripping member that grips the side edge of the film. The stretching device stretches the film in the width direction by moving the gripping member in the width direction while moving the gripping member in the film transport direction. The grip member at the grip start position is movable in the film width direction. The cooling device is provided between the support and the stretching device so as to be movable in the width direction of the film. The cooling device moves together with the gripping member at the gripping start position to cool the gripping region gripped by the gripping member of the film, thereby hardening the film. The cooling device has a pair of delivery nozzles and a suction nozzle. The pair of delivery nozzles is formed with a first delivery opening for delivering cooled gas, with the first delivery opening facing the side edge of the film, one film surface side and the other film surface side. And arranged. The suction nozzle is formed with a suction opening for sucking gas, and is disposed in a state where the suction opening is opposed to the side edge of the film.

  It is preferable that the pair of delivery nozzles have an air volume adjusting unit that adjusts the flow rate of the gas discharged from one and the other of the pair of delivery nozzles.

  Each of the pair of delivery nozzles has an outer first wall and an inner second wall in the width direction, and the first wall is arranged in a posture perpendicular to the film surface, and the first wall and the second wall The distance from the wall is preferably gradually reduced toward the first delivery opening.

  The solution casting apparatus preferably includes a drying device. The drying apparatus has a second delivery opening for discharging heated gas, and the second delivery opening is opposed to a central portion between one side end and the other side end of the film toward the stretching apparatus. The central portion is dried by a heated gas that is placed in a state.

  The stretching device has a cover that encloses the moving path of the gripping member, and the gripping member and the cover move together in the width direction, and the solution film forming equipment has a fixed length connecting member that connects the cover and the cooling device. It is preferable to provide.

  A supply unit that supplies cooled gas to the inside of the cover, and a guide unit that connects the cover and each of the pair of delivery nozzles and guides the cooled gas from the cover to each of the pair of delivery nozzles. Is preferred.

  It is preferable that the cooling device cools the range from the outer 5 mm to the inner 5 mm of the grip region in the width direction.

  The solution casting apparatus is particularly effective when the thickness of the grip region is in the range of 25 μm to 90 μm.

  The solution casting method of the present invention produces the film from the dope using the solution casting equipment.

  According to the present invention, the transport of the tenter with the clip is more stable, and the product yield is wider.

It is the schematic of the solution casting apparatus which implemented this invention. It is a plane schematic diagram of a clip tenter and a cooling device. It is explanatory drawing of a clip and a cover. It is a partial cross section schematic diagram of a cooling device.

  In FIG. 1, a solution casting apparatus 10 embodying the present invention is for continuously producing an optical film (hereinafter simply referred to as “film”) 11. The thickness of the film 11 to be manufactured is 40 μm in this embodiment, but the thickness is not particularly limited, and is in the range of 10 μm to 60 μm. In each of the embodiments shown below, as the thickness of the film 11 is thinner, the effect of improving the productivity is more remarkable. For example, when producing the film 11 in the range of 10 μm or more and 50 μm or less, compared to the conventional technique. Particularly significant effects have been confirmed.

  The solution casting apparatus 10 includes a casting device 12, a drying device 13, a cooling device 14, a clip tenter 15, a drying chamber 16, and a winding device 17 in order from the upstream side. In addition, in this example, although the film 11 used as a protective film of the polarizing plate of a liquid crystal display is manufactured, it is not restricted to this, For example, the film used as a phase difference film which has a protective function of a polarizing plate, or a low moisture-permeable film Can be manufactured.

  The casting apparatus 12 is for forming a film 11 containing a solvent from a dope 18 which is a polymer solution in which a polymer is dissolved in a solvent. In this example, the polymer of the dope 18 is cellulose triacetate (hereinafter referred to as TAC), and the solvent is a mixture of dichloromethane and methanol. However, the polymer of the dope 18 and the solvent are not limited to this. Other examples of the polymer include cellulose acylate different from TAC, polymethyl methacrylate (PMMA), and the like. Examples of cellulose acylate different from TAC include cellulose diacetate and cellulose acetate propionate. Other examples of the solvent include methanol, butanol, acetone, chloroform, and the like. These substances may be used alone or in combination, depending on the type of polymer used. Can be decided.

  The casting apparatus 12 includes a die 19, a casting belt 22, rotating rollers 23 and 24, a peeling roller 25 for peeling the casting film 20 from the casting belt 22, a temperature controller 26, a blower 27a, 27b and the like.

  The die 19 forms the flow of the dope 18 in the form of a film while guiding the supplied dope 18 inside, and flows out from the outlet 19a. The outlet 19a is formed in a slit shape extending in the depth direction of FIG. The casting belt 22 supports the dope 18 flowing out from the die 19 and forms the casting film 20. In the present embodiment, the outlet 19a has a short length in the longitudinal direction that is constant in the longitudinal direction. However, the present invention is not limited to this, and the length in the short direction is limited to each end in the longitudinal direction. It may be larger than the center.

  A casting belt 22 as a support formed in an annular shape is stretched around the rotating rollers 23 and 24. The longitudinal direction of the outlet 19 a coincides with the width direction of the casting belt 22. The rotating rollers 23 and 24 have rotating shafts 23a and 24a, and the rotating shafts 23a and 24a rotate in the circumferential direction by being rotated by a driving device (not shown). With this rotation, the casting belt 22 continuously runs in the longitudinal direction. The die 19 is provided on the rotating roller 23 in the present embodiment, but may be provided on the casting belt 22 from the rotating roller 23 toward the rotating roller 24. As the dope 18 continuously flows out from the die 19 toward the traveling belt 22 that travels, a casting film 20 is formed on the casting belt 22. The dope 18 flowing out from the outlet 19a of the die 19 is applied to the casting belt 22 to form a film-like bead 18a (see FIG. 3). In this example, the casting belt 22 is used as a support that is stretched around the rotation rollers 23 and 24 and travels by the rotation of the rotation rollers 23 and 24. However, the present invention is not limited to this, and a casting drum (not shown) is used. May be used.

  The casting belt 22 has a running speed in the range of 40 m / min to 90 m / min, and thus the production speed of the film 11 is in the range of 40 m / min to 90 m / min. In this embodiment, the running speed of the casting belt 22 and the production speed of the film 11 are set to 60 m / min.

  The temperature controller 26 is for setting the temperature of the belt surface of the casting belt 22 that supports the casting film 20 to a predetermined value. The temperature controller 26 is attached to the rotating rollers 23 and 24 and includes a temperature adjusting unit (not shown) that adjusts the temperature of the heat transfer medium, and heat transfer provided in the temperature adjusting unit and the rotating rollers 23 and 24. A heat transfer medium adjusted to a desired temperature is circulated between the flow path of the medium. By the circulation of the heat transfer medium, the temperature of the casting belt 22 is adjusted via the rotating rollers 23 and 24.

  The blowers 27 a and 27 b are an example of a dryer that dries the casting film 20. The blowers 27 a and 27 b are provided on the downstream side of the die 19 in the traveling direction of the casting belt 22. The blowers 27 a and 27 b have a plurality of slit-like openings extending in the width direction of the casting belt 22 on the facing surface facing the casting belt 22 along the running direction of the casting belt 22. Dry air is sent out from each opening. Thereby, in this embodiment, dry air is sent out toward the casting film 20 which passes. However, the direction in which the drying air is sent is not limited to this, and may be the traveling direction of the casting belt, for example. Further, in this example, the casting film 20 is dried using the blowers 27a and 27b as the dryer, but the dryer and the drying method are not limited to this, and for example, a far infrared heater is used as the dryer. A technique of drying by heating, or a technique of drying by heating the casting film 20 from the belt surface opposite to the side on which the casting film 20 is formed via the casting belt 22. A known material that can dry the cast film may be used.

  The stripping roller 25 is arranged such that its rotation axis is in parallel with the rotation axis of the rotation roller 23. In this example, the peeling roller 25 is disposed on the side opposite to the casting belt 22 with respect to the conveyance path of the film 11, and the film 11 is wound around the circumferential surface. The stripping roller 25 rotates following the conveyance of the film 11. With the film 11 wound around the stripping roller 25, the film 11 is pulled toward the downstream side of the solution casting equipment 10, whereby the casting film 20 is peeled from the casting belt 22 at a predetermined stripping position. Note that the peeling roller 25 may be rotated in synchronization with the conveyance of the film 11 by a motor.

  A plurality of rollers 28 are arranged on the conveyance path from the casting device 12 to the clip tenter 15, and these rollers 28 guide the film 11 to the clip tenter 15. The drying device 13 is provided in the vicinity of the conveyance path of the film 11 set by a plurality of rollers 28. The drying device 13 is for drying the film 11 containing a solvent. The drying device 13 is a blower that sends out heated gas, and is provided on the side of the peeling surface of the film 11 that has been peeled off from the casting belt 22. A plurality of nozzles 13 a are formed along the transport direction X of the film 11 on the facing surface facing the film transport path. A plurality of nozzles 13a each having an opening (hereinafter referred to as a second delivery opening) 13b for delivering heated gas is formed at the tip of each nozzle 13a. These nozzles 13a extend in the width direction Y (see FIG. 2) of the film 11, and the second delivery opening 13b also has a slit shape extending in the width direction Y. The drying device 13 delivers heated gas from each second delivery opening 13 b facing the film 11. In this example, a blower is used as the drying device 13, but the drying method of the drying device 13 and the film 11 is not limited to this. For example, heating with a far infrared heater may be used, and the film 11 can be dried. May be used. However, from the viewpoint of drying the film 11 more efficiently, the drying device 13 is most preferably a blower as in this embodiment. Further, the drying device 13 may be disposed on the surface opposite to the peeling surface side of the film 11 with respect to the transport path of the film 11.

  The cooling device 14 is provided between the casting belt 22 and the clip tenter 15. In this embodiment, the cooling device 14 is provided between the drying device 13 disposed downstream of the casting device 12 and the clip tenter 15. ing. Specifically, the cooling device 14 is connected upstream of the clip tenter 15 as will be described later with reference to another drawing.

  The clip tenter 15 is a stretching device that stretches the film 11 in the width direction. The clip tenter 15 has a casing 15 a that surrounds the transport path of the film 11. The clip tenter 15 has an air blower 30 inside the casing 15a, and the air blower 30 performs temperature adjustment and drying of the film 11 being transported by supplying a temperature-adjusted gas to the film 11. . In the clip tenter 15, the film 11 is heated in order to stretch the film 11 as described later. Therefore, the blower 30 supplies a gas heated to a predetermined temperature to the film 11. Details of the clip tenter 15 will be described later with reference to another drawing.

  An ear clip device 31 may be provided downstream of the clip tenter 15 as in the present embodiment. The edge-cutting device 31 cuts off both sides in the width direction Y of the film 11. The separated both sides are sent to the crusher 32 by air blowing, crushed by the crusher 32, and reused as a raw material such as a dope.

  The drying chamber 16 is for further drying while conveying the film 11. A large number of rollers 34 are provided in the drying chamber 16, and the film 11 is conveyed while being wound around each of the rollers 34. The temperature and humidity of the atmosphere in the drying chamber 16 are adjusted by an air conditioner (not shown).

  The drying chamber 16 includes a drying unit 16a that dries by heating the film 11, and a cooling unit 16b that cools the film 11, and the cooling unit 16b is located on the downstream side of the drying unit 16a. The cooling unit 16b cools the film 11 whose temperature has been increased in the drying unit 16a, for example, until it reaches room temperature.

  In the present embodiment, a knurling roller 35 is provided downstream of the cooling unit 16b. The knurling roller 35 applies knurling composed of a large number of irregularities on both sides of the film 11. The winding device 17 has a press roller 36. A winding core 37 for winding the film 11 is set in the winding device 17, and the winding core 37 is rotated in the circumferential direction by a drive unit (not shown) to hold the film 11 on the winding core 37 while being pressed by the press roller 36. Wind up.

  As shown in FIG. 2, an inlet 15 i and an outlet 15 o for the film 11 are formed in the casing 15 a of the clip tenter 15. The clip tenter 15 includes a plurality of clips 40 as gripping members that grip the side end portion 11s. The plurality of clips 40 are attached to a clip moving part 41 (see FIG. 3) such as a chain formed in an annular shape with a predetermined interval. The clip moving part 41 is attached so as to be movable along the rail 42, and meshes with a turn wheel 15b disposed on the inlet 15i side and a sprocket 15c disposed on the outlet 15o side. As the sprocket 15c rotates, the clip moving unit 41 moves, and the clip 40 circulates and moves along the rail 42 by this movement. As described above, the rail 42 is a moving path of the clip 40.

  The clip 40 starts gripping the guided film 11 in the vicinity of the inlet 15i, moves toward the outlet 15o, and releases the grip in the vicinity of the outlet 15o. The clip 40 whose grip has been released moves again to the vicinity of the entrance 15i to grip the newly guided film 11. The clip tenter 15 extends in the width direction Y while transporting the film 11 in the longitudinal direction by moving the clip 40 in the longitudinal direction and the width direction Y of the film 11. That is, the longitudinal direction of the film 11 is the transport direction X. In FIG. 2, a sign Pa is assigned to a grip start position where gripping by the clip 40 is started, and a sign Pb is assigned to a grip release position where the grip is released. FIG. 2 shows an example in which the grip start position Pa is downstream of the inlet 15i and the grip release position Pb is upstream of the outlet 15o. However, the grip start position Pa may be upstream of the inlet 15i. In addition, the grip release position Pb may be downstream of the outlet 15o.

  In this example, the distance between one rail 42 and the other rail (hereinafter referred to as the distance between the rails) from the upstream side to the downstream side in the transport direction X is substantially constant, and the distance between the rails. The second section in which the distance between the rails gradually increases, the third section in which the distance between the rails gradually decreases, and the fourth section in which the distance between the rails is substantially constant are provided, and the film 11 at the outlet 15o is larger than the width of the film 11 at the inlet 15i. The distance between each rail is set so as to increase the width of the rail. However, the number of sections and the change in the distance between the rails in each section are not limited to this example, and are appropriately set according to the optical performance such as retardation of the target film 11 or mechanical properties.

  The clip tenter 15 includes a cover 43 that surrounds the rail 42, the clip moving unit 41, and the clip 40. The cover 43 is movable in the width direction Y and is moved in the width direction by the shift mechanism 46. The cover 43 and the rail 42 are fixed as will be described later, and the clip 40 moves on the rail 42. Therefore, the cover 43 and the clip 40 move together in the width direction Y. The shift mechanism 46 moves the cover 43 so that the position of the rail 42 in the width direction Y becomes a target position. For example, the position in the width direction Y of the cover 43 at the grip start position Pa can be changed during manufacture so as to correspond to the meandering of the guided film 11. The shift mechanism 46 may be operated by an operator (operator), and is also operated by the operator in this embodiment. When the shift mechanism 46 is operated by an operator, for example, the position in the width direction Y of the rail 42 at the grip start position Pa and the guided film 11 are observed with a monitor, and the cover 43 is moved according to the meandering of the film 11. Move it. As a result, at the grip start position Pa, the film 11 is securely gripped by the clip 40 moving on the rail 42, and the grip region CR (see FIG. 3) of the film 11 gripped by the clip 40 is the width direction Y. At a certain position.

  The cooling device 14 upstream of the clip tenter 15 is for hardening the grip region CR (see FIG. 3) of the film 11 gripped by the clip 40. The cooling device 14 is provided in each of the passage paths through which each side end portion 11 s of the film 11 that goes to the clip tenter 15 passes.

  Similarly to the cover 43, the cooling device 14 is also provided so as to be movable in the width direction Y. In this example, the cover 43 and the cooling device 14 are not substantially changed in length, that is, they are connected by a connecting member 47 having a fixed length. Move in direction Y. As a result, the cooling device 14 moves integrally with the clip 40 at the grip start position Pa.

  Further, the cover 43 has a partition wall 43p that partitions the inside in the width direction X. By this partition wall 43p, inside the cover 43, the forward path portion 43g that surrounds the portion of the rail 42 in which the clip 40 goes from the grip start position Pa to the grip release position Pb, and the rail 42 that goes from the grip release position Pb to the grip start position Pa. The return path part 43r surrounding this part is formed. The clip tenter 15 has a supply unit 48 that supplies the cooled gas to the inside of the cover 43, specifically, to the return path unit 43r.

  The supply part 48 is for cooling the clip 40 toward the grip start position Pa. In the clip tenter 15, by supplying the gas heated from the blower 30 to the film 11 as described above, the target optical performance or the like is expressed on the film 11. For this reason, the clip 40 is at a high temperature due to the gas from the blower 30 while moving from the grip start position Pa to the grip release position Pb. When the film 11 is newly gripped by returning to the grip start position Pa in a high temperature state, the film 11 is foamed or the grip region CR (see FIG. 3) is softened. Therefore, the supply section 48 sends the cooled gas to the return path section 43r of the cover 43, thereby lowering the temperature of the clip 40 while returning from the grip release position Pb to the grip start position Pa.

  The cooling device 14 includes a delivery nozzle 51 that sends out the cooled gas toward the gripping region CR, and a suction nozzle 52 that sucks the gas. The delivery nozzle 51 is provided on each of the film surface side and the other film surface side of the film 11. When not distinguished from each other, the delivery nozzle 51 will be described with reference numeral 51. This will be described using reference numerals 51A and 51B as described later with reference to another drawing. The delivery nozzle 51 may be connected to the return path 43r of the cover 43, which is also the case in this embodiment. Specifically, the upstream end 43u of the cover 43 described above is opened so that the clip 40 passes through, and the upstream end 43u of the return passage 43r and the delivery nozzle 51 are connected by a pipe 53. The pipe 53 is a guide part that guides the cooled gas supplied from the supply part 48 to the return path part 43 r to the delivery nozzle 51. Thus, since the pipe 53 guides the cooled gas in the return passage 43r to the delivery nozzle, the connection position of the end of the pipe 53 on the cover 43 side needs to be the upstream end 43u of the return passage 43r. There is no. For example, an opening may be provided at any position on the return path 43r, and the pipe 53 may be connected to the opening. As described above, the supply unit 48 has a function of hardening the grip region CR of the film 11 in the cooling device 14 in addition to the clip cooling function of cooling the clip 40.

  The blower nozzle 51 has an air volume adjusting unit 56. The air volume adjusting unit 56 is for adjusting the flow rate of the gas emitted from the blowing nozzle 51 toward the film 11. In this example, the air volume adjusting unit 56 is provided in the pipe 53, and adjusts the flow rate of the gas that is guided from the return path unit 43 r to the blowing nozzle 51, thereby adjusting the flow rate of the gas that exits from the blowing nozzle 51. However, the air volume adjusting unit 56 is not limited to this, and is provided integrally with the blowing nozzle 51, for example, and adjusts the opening degree of the first sending opening 66 (see FIG. 4) for sending the gas of the blowing nozzle 51 to adjust the gas flow. The flow rate may be adjusted. Note that the cooled gas supplied to the blower nozzle 51 is not limited to the gas in the cover 43. For example, a blower (not shown) may be provided outside the clip tenter 15 and the cooled gas may be supplied from the blower to the blow nozzle 51. In this case, the air volume adjusting unit 56 may be provided between the blower and the blower nozzle 51, for example.

  The suction nozzle 52 is for preventing the cooled gas from the blowing nozzle 51 from flowing toward the center of the film 11 in the width direction Y. The suction nozzle 52 is disposed outside the side edge 11 e of the film 11 in the width direction Y, and has a suction adjustment unit 57. The suction adjusting unit 57 guides the gas emitted from the blower nozzle 51 toward the film 11 to the side edge side of the film 11 in the width direction Y by adjusting the suction amount of the gas sucked by the suction nozzle 52.

  The movement of the cover 43 and the clip 40 will be described with reference to FIG. The cover 43 and the rail 42 are fixed, and the clip 40 and the clip moving part 41 are fixed. The clip moving part 41 is attached so as to be movable along the rail 42. Thereby, the clip 40 moves in the width direction Y integrally with the cover 43 moved by the shift mechanism 46.

  The clip 40 includes a U-shaped frame 61, a flapper 62, and a rotation shaft 63. The flapper 62 is rotatably attached to the frame 61 by a rotation shaft 63. The lower end surface of the flapper 62 is a pressing surface 62 a that presses the side end portion 11 s of the film 11 with the support surface 61 a that supports the film 11 of the frame 61. The flapper 62 changes the posture between a holding posture in which the pressing surface 62a is in contact with the film 11 supported by the support surface 61a and a retracting posture in which the pressing surface 62a is retracted from the film 11 supported by the support surface 61a. As shown in FIG. 3, the flapper 62 is in a gripping posture in the forward path portion 43g and in a retracted posture in the return path portion 43r. 3 and 4, the film 11 is depicted as a mode in which a part of the side end portion 11s is formed thicker than the central portion 11c by the aforementioned necking.

  The side end portion 11s of the film 11 is gripped by the pressing by the pressing surface 62a and the support surface 61a. The aforementioned gripping region CR is a region pressed by the pressing surface 62a and the support surface 61a as shown in FIG. In this example, the entire region in the width direction Y of the side end portion 11s is in the cover 43. However, the present invention is not limited to this example, and a partial region on the side edge 11e side of the side end portion 11s is in the cover 43. The mode which enters can be used.

  As described above, the cooling device 14 includes the delivery nozzle 51A disposed on one film surface (hereinafter referred to as the first film surface) 11a side, and the other film surface (hereinafter referred to as the second film surface) 11b side. And a delivery nozzle 51B. The delivery nozzle 51 </ b> A and the delivery nozzle 51 </ b> B are provided in a target posture with respect to the film 11. Since the delivery nozzle 51B has the same configuration as the delivery nozzle 51A, the delivery nozzle 51A will be described in detail below, and the description of the delivery nozzle 51B will be omitted.

  The delivery nozzle 51 </ b> A has a first delivery opening 66 for discharging the cooled gas at the tip. In the delivery nozzle 51A, the positional relationship in the width direction Y between the first delivery opening 66 and the rail 42 is constant, and the first delivery opening 66 is opposed to the gripping region CR of the side end portion 11s. Arranged. Thereby, the cooled gas delivered from the first delivery opening 66 is blown to the gripping region CR, and the gripping region CR is cooled and hardened.

  The region in the width direction Y of the side end portion 11s cooled by the delivery nozzle 51A is preferably suppressed to a range of 5 mm from the outside 5 mm to the inside 5 mm of the grip region CR. This is because prevention of breakage of the film 11 due to gripping with the clip 40 and securing of the central portion 11c with a wider width are more reliably achieved. Thus, in order to suppress the area of the side end portion 11s cooled by the delivery nozzle 51A within the above range, the delivery nozzle 51A has the following configuration.

  The delivery nozzle 51A has an outer first wall 67 and an inner second wall 68 in the width direction Y. The first wall 67 is arranged in a posture perpendicular to the first film surface 11 a, and the distance D between the first wall 67 and the second wall 68 gradually decreases toward the first delivery opening 66. That is, the second wall 68 is arranged in such a posture that it is inclined toward the side edge 11e of the film 11 in the width direction Y as it goes to the first delivery opening 66. Since the side end portion 11s is formed thicker than the central portion 11c as described above, strictly speaking, the film surface of the side end portion 11s is not flat unlike the film surface of the central portion 11c. For this reason, the first film surface 11a and the second film surface 11b are defined by the respective film surfaces in the central portion 11c.

  In order to suppress the region of the side end portion 11s cooled by the delivery nozzle 51A within the above range, in the present embodiment, the above-described suction nozzle 52 is further arranged. The suction nozzle 52 has a suction opening 71 at the tip for sucking gas. The suction nozzle 52 is arranged with the suction opening 71 facing the side edge 11e.

  The delivery nozzle 51 also has a function of suppressing curling of the side end portion 11 s of the film 11 toward the clip tenter 15. In the present embodiment, the flow rate of each gas from the delivery nozzle 51A and the delivery nozzle 51B is independently adjusted by the air volume adjusting unit 56, and thus the flow rate of the gas emitted from the pair of delivery nozzles 51A and 51B. Is preferably adjusted. Specifically, when the side end 11s curls on the first film surface 11a side, the flow rate from the delivery nozzle 51B disposed on the second film surface 11b side may be increased. On the other hand, when the side end portion 11s curls on the second film surface 11b side, the flow rate from the delivery nozzle 51A disposed on the first film surface 11a side may be increased.

  The operation of the above configuration will be described. The dope 18 is continuously supplied to the die 19 by a pump (not shown). Inside the die 19, while the dope 18 is guided toward the outlet 19 a, the width of the flow is continuously increased to form a film, and the die 19 continuously flows out from the outlet 19 a. The dope 18 flows out toward the traveling casting belt 22, whereby a casting film 20 is formed on the casting belt 22. A bead 18 a is formed between the outlet 1 and the casting belt 22.

  On the casting belt 22, the casting film 20 is dried by the drying air from the blowers 27a and 27b and has a self-supporting property before being peeled off. The stripping roller 25 is dried to such an extent that it can be transported, and the casting film 20 having self-supporting properties is continuously peeled off from the casting belt 22 to form the belt-like film 11. The solvent content of the cast film 20 at the time of peeling is preferably in the range of 20% by mass to 250% by mass. In the present specification, the solvent content (unit:%) is a value based on the dry amount. Specifically, when the mass of the solvent is MS and the mass of the casting film 20 or the film 11 is MF, The percentage obtained by {MS / (MF-MS)} × 100.

  While passing through the drying device 13, the film 11 is heated in the whole area in the width direction Y in this example, so that drying proceeds. In this example, the entire region in the width direction Y of the film 11 is dried, but at least a central portion between one side end portion 11s (see FIG. 2) of the film 11 and the other side end portion 11s. What is necessary is just to dry 11c (refer FIG. 2).

The cover 43 of the clip tenter 15 is displaced in the width direction Y by the shift mechanism 46 so that the side end portion 11s is gripped by the clip 40 at the grip start position Pa. Thereby, the grip region CR in the width direction Y is set. Since the cooling device 14 moves in the width direction Y integrally with the cover 43, the grip region CR of the film 11 toward the clip tenter 15 passes through the first delivery openings 66 of the pair of delivery nozzles 51A and 51B. As a result, the grip region CR is reliably cooled and hardened, and is gripped by the clip 40 in a hard state. Even if the film 11 meanders upstream of the clip tenter 15, since the cooling device 14 moves in the width direction Y integrally with the cover 43, the position in the width direction Y of the gripping region CR is constant in the longitudinal direction of the film 11. And the area | region in the width direction Y cooled is suppressed narrowly. Thereby, since the area | region where optical performance is influenced by cooling is suppressed narrowly, the picking width of the product in the center part 11c becomes wider.

  Since the first wall 67 is arranged in a posture perpendicular to the first film surface 11a, the cooled gas flowing on the first wall 67 side is directed toward the grip region CR with respect to the first film surface 11a. It is sent out almost vertically. Further, since the second wall 68 is arranged in a posture inclined toward the side edge 11e side of the film 11 in the width direction Y toward the first delivery opening 66, the cooled gas flowing on the second wall 68 side is arranged. Is sent toward the side edge 11e side of the grip region CR. As a result, the region of the side end portion 11s cooled by the delivery nozzle 51A is narrow and sufficient, for example, a range from the outer 5 mm to the inner 5 mm of the grip region CR.

  Since the suction nozzle 52 is arranged, the region of the side end portion 11s cooled by the delivery nozzle 51A is narrow and sufficient, for example, a range from 5 mm outside to 5 mm inside the grip region CR.

  Further, since the flow rate of the gas discharged from the pair of delivery nozzles 51A and 51B is adjusted, the film 11 is guided to the clip tenter 15 in a state where curling of the side end portion 11s is further suppressed. For this reason, the side end portion 11s is more reliably gripped at the grip start position Pa. This curl suppressing function is considered to be an action of drying the side end portion 11s by a gas flow, rather than an action of cooling by the cooled gas.

  Since the delivery nozzle 51 and the return path part 43r are connected by the pipe 53, the cooled gas from the supply part 48 flows between the clip 40 in the return path part 43r and the grip region CR of the film 11 toward the clip tenter 15. Used for both cooling.

  When the thickness T of the gripping region CR is in the range of 25 μm or more and 90 μm or less, particularly in the range of 35 μm or more and 85 μm or less, and further in the range of 40 μm or more and 80 μm or less, This is particularly noticeable. When the thickness of the grip region CR is not constant in the width direction Y, the largest value in the width direction Y is set as the thickness T.

  The film 11 sent out from the clip tenter 15 is sent to the drying chamber 16 after both sides including the gripping region CR in the clip tenter 15 are cut off by the ear clip device 31. The drying unit 16 a of the drying chamber 16 sends the film 11 downstream while supporting the film 11 with the roller 34. The film 11 is further dried by passing through the drying chamber 16 in which the temperature and humidity of the atmosphere are adjusted. The film 11 is cooled to, for example, room temperature by passing through the cooling unit 16b.

  After the film 11 is cooled, knurling is imparted to both sides by a knurling roller 35. The film 11 to which the knurling is applied is wound around the winding core 37 in a roll shape by the winding device 17.

DESCRIPTION OF SYMBOLS 10 Solution casting apparatus 11 Film 11a 1st film surface 11b 2nd film surface 11c Center part 11e Side edge 11s Side edge part 12 Casting apparatus 13 Drying apparatus 13a Nozzle 13b 2nd delivery opening 14 Cooling apparatus 15 Clip tenter 15a Casing 15b Turn wheel 15c Sprocket 15i Inlet 15o Outlet 16 Drying chamber 16a Drying unit 16b Cooling unit 17 Winding device 18 Dope 19 Die 19a Outlet 20 Casting film 22 Casting belt 23, 24 Rotating roller 25 Stripping roller 26 Temperature controller 27a, 27b Air blower 28 Roller 30 Air blower 31 Ear opener 32 Crusher 34 Roller 35 Knurling imparting roller 36 Press roller 37 Winding core 40 Clip 41 Clip moving part 42 Rail 43 Cover 43g Outward part 43p Bulkhead 43 Return path part 46 Shift mechanism 47 Connecting member 48 Supply part 51 Delivery nozzle 52 Suction nozzle 53 Piping 56 Air volume adjustment part 57 Suction adjustment part 61 Frame 61a Support surface 62 Flapper 62a Press surface 63 Rotating shaft 66 First delivery opening 67 First wall 68 Second wall 71 Suction opening CR Gripping area Pa Gripping start position Pb Gripping release position T Gripping area thickness

Claims (9)

In a solution casting apparatus for continuously forming a cast film from a dope in which a polymer is dissolved in a solvent on a traveling support, forming a film by peeling off the cast film, and drying the film ,
A dryer for drying the cast film;
A gripping member for gripping a side edge of the film; the gripping member is stretched in the width direction by moving the gripping member in the transport direction of the film; A stretching device that is movable in the width direction of the film;
It is provided between the support and the stretching device so as to be movable in the width direction of the film, and is gripped by the gripping member of the film by moving integrally with the gripping member at the gripping start position. A cooling device that hardens by cooling the gripping area ,
The cooling device is
A first delivery opening for delivering the cooled gas is formed, and the first delivery opening is disposed on one film surface side and the other film surface side in a state where the first delivery opening is opposed to the side end portion of the film. A pair of delivery nozzles,
A suction opening for sucking gas is formed, and a suction nozzle arranged in a state where the suction opening is opposed to a side edge of the film;
A solution casting apparatus. 2. The solution casting apparatus according to claim 1 , wherein the pair of delivery nozzles includes an air volume adjustment unit that adjusts a flow rate of the gas discharged from one and the other of the pair of delivery nozzles. Each of the pair of delivery nozzles is
An outer first wall and an inner second wall in the width direction;
The first wall is arranged in a posture perpendicular to the film surface,
The solution casting apparatus according to claim 1 or 2 , wherein a distance between the first wall and the second wall is gradually decreased toward the first delivery opening. A second delivery opening for delivering heated gas, the second delivery opening being opposed to a central portion between one side end and the other side end of the film toward the stretching device; The solution casting apparatus according to any one of claims 1 to 3 , further comprising a drying device that is disposed in a heated state and dries the central portion with the heated gas. The stretching device has a cover that surrounds the moving path of the gripping member, and the gripping member and the cover move integrally in the width direction,
The solution casting apparatus according to any one of claims 1 to 4 , further comprising a fixed-length connecting member that connects the cover and the cooling device. A supply unit for supplying a cooled gas to the inside of the cover;
A guide for connecting the cover and each of the pair of delivery nozzles and guiding the cooled gas from the cover to each of the pair of delivery nozzles;
The solution casting apparatus according to claim 5 . The solution casting apparatus according to any one of claims 1 to 6 , wherein the cooling device cools a range from 5 mm outside to 5 mm inside the gripping region in the width direction. The solution casting apparatus according to any one of claims 1 to 7 , wherein a thickness of the gripping region is in a range of 25 µm to 90 µm. The solution casting method which manufactures the said film from the said dope using the solution casting equipment of any one of Claim 1 thru | or 8 .

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