JP5426627B2 - Casting apparatus, casting film forming method and solution casting method - Google Patents

Description

The present invention, casting apparatus, a forming method and a solution casting method of casting film.

  With the increase in the screen size of a liquid crystal display (LCD), an optical film used for the LCD is also required to have a large area. The optical film is manufactured to be long and then cut into a predetermined size according to the dimensions of the LCD. Therefore, in order to manufacture an optical film having a larger area, it is necessary to manufacture a long optical film having a width larger than that of the conventional one.

  As a typical method for producing a long optical film, there is a solution casting method. As is well known in the solution casting method, a dope in which a polymer is dissolved in a solvent is cast on a moving casting support, and a casting film made of the dope is formed on the casting support. In this method, the cast film is peeled off from the cast support and dried.

  As the casting support, a metal endless band stretched around a plurality of metal drums is used. The maximum width of the film that can be produced by the solution casting method is limited by the width of the endless band. Therefore, a larger width endless band is required to produce a larger width film. However, until now, only endless bands with a width of about 2 m have been obtained.

  Therefore, in Patent Document 1, an endless band having a larger width than the conventional one is welded by welding a central band that is a central part in the width direction and a pair of side bands that are each side part in the longitudinal direction. It has gained.

Korean Patent Publication No. 2009-0110082

  However, when the solution casting method is performed continuously for a long time (for example, 700 hours or more) using an endless band as described in Patent Document 1, a shaving powder failure or a thickness unevenness failure occurs. As a result of the inventor's earnest study, it has been found that the shaving powder failure and the thickness unevenness failure are caused by the projection of the welded portion and the residual stress.

  Furthermore, as a result of intensive studies by the inventors, it has been found that the endless band as described in Patent Document 1 is likely to warp in the width direction due to the welded portion extending in the longitudinal direction. In particular, warping tends to occur from the end in the width direction of the endless band, that is, from the center band to the side band. If the solution casting method is performed using an endless band whose width direction end is warped, unevenness in the thickness of the cast film occurs due to this warpage. Even if the cast film having such thickness unevenness is dried, it becomes a film having thickness unevenness (hereinafter referred to as thickness unevenness failure).

  In addition, when the endless band is stretched over the metal drum so that the inner surface of the endless band curved by warpage is in contact with the peripheral surface of the metal drum, the end of the band is locally on the side of the endless band. It will contact the peripheral surface. If the state where the band end locally contacts the peripheral surface of the driving roller is continued, the deformation of the side portion of the endless band increases, so that the above-described thickness unevenness failure is likely to occur.

  Further, when the cast film with uneven thickness is peeled off, a failure to peel off is likely to occur, and when the cast film with uneven thickness is dried, foaming is likely to occur.

  In order to correct warping of the endless band, it is also possible to increase the moving tension applied to the endless band by moving the metal drum so that the interval between the metal drums becomes large with the endless band being wound. However, if the solution casting method is performed in a state where the moving tension applied to the endless band is increased, the film thickness unevenness failure and the shaving powder failure due to the welded portion are likely to occur.

  The present invention solves such problems, and an object thereof is to provide a metal drum, a casting apparatus, a casting film forming method, and a solution casting method.

The casting apparatus of the present invention supports a metal endless band having a welded portion that is rotatably supported and extends in the longitudinal direction on the circumferential surface, and a groove for escaping from the welded portion is circumferentially provided on the circumferential surface. a metallic drum which extends, welded portion is wound around a metal drum to be positioned above the groove, the endless band is moved by the rotation of the metal drum, the dope containing a polymer and a solvent on the surface of the endless band A casting die that flows out, a membrane dryer that evaporates the solvent from the casting film by applying heated air to the casting film that is formed of the outflowing dope and formed on the surface, and the casting film is connected to the endless band. Among them, a peeling machine that peels from the endless band at the part supported by the metal drum for peeling to make a wet film, a peeling drum cooler that cools the metal drum for peeling, and a metal drum for peeling. And a band back surface coolers for cooling the welded portion of the endless band moving from the back side.

The dope flowing out from the casting die reaches a portion of the endless band supported by the casting metal drum, and a casting drum cooler for cooling the casting metal drum and the dope of the endless band reach. And a band surface cooler that is provided between the position where the casting film is peeled off and the position where the casting film is peeled off and cools the welded portion supported by the metal drum for casting from the surface side .

Alternatively, the casting apparatus of the present invention supports a metal endless band having a welded portion that is rotatably supported and extends in the longitudinal direction on the circumferential surface, and a groove for escaping from the welded portion is provided on the circumferential surface. including a metal drum which is extended in the direction, the welds are wound around the metallic drum to be positioned above the groove, and Rue down dress band move by the rotation of the metallic drum, a polymer and a solvent dope flows toward the surface of the e down dress band, et down and out casting die flow to reach to the supporting portion in the metallic drum for extending dress band, Ri Do from spilled doped front surface on by applying a heated air stream to the casting film formed on a membrane dryer to evaporate the casting film or al SOLVENTS, a peeling machine according to the wet film was peeled off the casting film from the endless band, for casting Casting drum cooler for cooling metal drums and endless bar Position and the casting membrane dope reaches of de is provided between the position to be peeled off, and a band surface coolers for cooling the welded portion supported on a metal drum for casting from the surface side.

It is preferable that the groove is formed in an annular shape .

Moreover, it is preferable that the bottom of the groove is flat .

The casting film forming method of the present invention forms the casting film on the surface of the endless band using the above casting apparatus.

The solution casting method of the present invention uses the above-described casting apparatus to form a casting film on the surface of the endless band, and peels the casting film from the endless band to form a film.

  ADVANTAGE OF THE INVENTION According to this invention, the strip | belt-shaped film whose width | variety is wider than before can be manufactured efficiently, suppressing the thickness nonuniformity failure of a film resulting from a welding part, and a cutting powder failure.

  Although a welded portion also exists in a conventional endless band (having a width of 2 m or less), the welded portion extends in the width direction. In the film obtained by using such an endless band, a portion affected by an adverse effect such as thickness unevenness caused by the welded portion extends in the width direction similarly to the welded portion. Therefore, by cutting the obtained belt-like film in the width direction, it was easy to remove a part that had an adverse effect from the product film. On the other hand, when an endless band having a welded portion extending in the longitudinal direction is used, unlike a conventional endless band, it is not easy to remove a portion adversely affected by the welded portion. According to this invention, the part formed on the welding part among cast films can be included in the film for products.

  According to the present invention, even in such a case, it is possible to efficiently produce a strip-shaped film having a width wider than that of the conventional film while suppressing the thickness unevenness failure and the shaving powder failure due to the welded portion.

It is a side view which shows the outline | summary of the manufacturing equipment of a band. It is a top view which shows the outline | summary of a band manufacturing equipment. It is a side view which shows the outline | summary of a welding unit. It is a top view which shows the outline | summary of a welding unit. It is a VV line sectional view showing an outline of a welding support roller. It is explanatory drawing of a weld bead and its periphery. It is the schematic of a taper roller. It is the schematic of a clip. It is the schematic of a band. It is a side view which shows the outline | summary of solution casting apparatus. It is a side view which shows the outline | summary of a casting apparatus. It is a perspective view which shows the outline | summary of a casting apparatus main body. It is a perspective view which shows the outline | summary of a horizontal drum. It is the P1-P1 sectional view taken on the line of a band. It is a perspective view which shows the outline | summary of a band back surface cooler. It is a P2-P2 line sectional view of a band.

  The band manufacturing equipment 10 shown in FIG. 1 and FIG. 2 creates a long band member 13 including a long central member 12 and side members 11 provided on both sides of the central member 12 in the width direction.

  The side member 11 and the central member 12 are metal sheet materials, respectively. The side member 11 is a narrow sheet material having a relatively narrow width. The side member 11 and the central member 12 are preferably formed from the same material, and more preferably formed through the same raw material and forming process. For example, as the side member 11 and the central member 12, it is preferable to use those formed from stainless steel.

  As the central member 12, a band that has been used as a conventional casting support may be used. The central member 12 is wider than the side member 11, and the width of the central member 12 in this embodiment is constant in the range of 1500 mm to 2100 mm, and the width of the side member 11 is constant in the range of 50 mm to 500 mm. is there.

  The band manufacturing facility 10 includes a delivery unit 16, a butting unit 17, a welding unit 18, a heating unit 19, and a winding device 20.

(Sending part)
The sending unit 16 includes a first sending device 23 that sends out the side member 11 and a second sending device 24 that sends out the central member 12, and sends the side member 11 and the central member 12 to the butting unit 17 independently. . The side member 11 wound in a roll shape is set in the first delivery device 23, and the side member 11 is unwound and sent to the butting portion 17. In the second delivery device 24, the central member 12 wound in a roll shape is set, and the central member 12 is unwound and sent to the butting portion 17.

  The abutting portion 17 abuts the side member 11 and the central member 12 that are independently guided so that the side edge 11e of the side member 11 and the side edge 12e of the central member 12 are in contact with each other. The abutting portion 17 includes a first roller 26 and a second roller 27 that are sequentially arranged on the conveyance path of the central member 12 from the upstream side, a third roller 28 that is disposed on the conveyance path of the side member 11, and the side member 11 and the central member. It is preferable to have the 4th roller 29 distribute | arranged to a conveyance path so that both of 12 may be supported.

  The fourth roller 29 is a butt that supports the fed side member 11 and the central member 12 at a butt position Ph where one side edge of the side member 11 and one side edge of the central member 12 start to contact each other. It is a support roller.

  The second roller 27 and the third roller 28 respectively adjust the conveyance path of the central member 12 and the conveyance path of the side member 11 so that the central member 12 and the side member 11 are in contact with each other on the peripheral surface of the fourth roller 29. To do.

  The 2nd roller 27 adjusts the conveyance path | route of the center member 12, and controls the passage path | route of the side edge 12e which should be welded with the side member 11 toward the abutting position Ph. The second roller 27 is movable in the width direction Y of the central member 12. The shift mechanism 32 moves the second roller 27 in the width direction Y.

  Between the second roller 27 and the fourth roller 29, there is position detecting means 34 for detecting the passing position of one of the side edges 12e of the central member 12 and sending a signal of the detected passing position to the controller 33. Arranged. The controller 33 obtains the displacement amount of the second roller 27 in the width direction Y based on the sent signal of the passing position, and sends the displacement amount signal to the shift mechanism 32. The shift mechanism 32 changes the inclination of the second roller 27 and the position of the second roller 27 in the width direction Y of the central member 12 based on the sent displacement amount signal. Thus, the central member 12 is displaced in the width direction Y by changing the inclination and position of the second roller 27.

  The first roller 26 is preferably provided with a shift mechanism 37. By this shift mechanism 37, the first roller 26 pushes the central member 12 toward the second roller 27 from one member surface. Depending on the amount of displacement of the first roller 26, the pressing force of the first roller 26 against the central member 12 changes, and the winding central angle of the central member 12 wound around the second roller 27 is adjusted by adjusting the pressing pressure. Can be controlled. By controlling the winding center angle, the amount of displacement of the central member 12 in the width direction Y by the second roller 27 can be controlled more precisely.

  The 3rd roller 28 adjusts the conveyance path of the side member 11, and adjusts the passage path of one side edge 11e which should be welded with the center member 12 toward the abutting position Ph. The third roller 28 is provided with a controller 38 that controls the orientation in the longitudinal direction. For example, the controller 38 moves the longitudinal direction of the third roller 28 to the side so that the angle θ1 formed by the circumferential direction in the contact area while in contact with the side member 11 and the transport direction X of the central member 12 changes. It changes along the member surface of the member 11.

  As described above, it is preferable to use the first roller 26 to the third roller 28 to control the butting position Ph on the fourth roller 29. The first roller 26 to the third roller 28 are preferably drive rollers that rotate in the circumferential direction. By rotating in the circumferential direction, the first roller 26 and the second roller 27 also function as a transport unit for the central member 12, and the third roller 28 also functions as a transport unit for the side member 11. By using the first roller 26 to the third roller 28 as driving rollers, the control of the conveyance path between the side member 11 and the central member 12 becomes more reliable, and the first roller 26 between the side member 11 and the central member 12 becomes more reliable. The slip on the third roller 28 is prevented and the member surface is prevented from being damaged.

(Welding unit)
The welding unit 18 welds the side member 11 and the central member 12 supplied from the butt portion 17 in a state where the side edges 11e and 12e are in contact with each other. By being continuously supplied from the abutting portion 17, a longitudinal welding process of welding the side member 11 and the central member 12 in the longitudinal direction can be performed. The welding unit 18 includes a welding device 42. Examples of the welding device 42 include a laser welding device. As the laser welding apparatus, for example, a CO ₂ laser welding apparatus or a YAG laser welding apparatus can be used. In this embodiment, a case where a CO ₂ laser welding apparatus is used as the welding apparatus 42 will be described.

The welding device 42 emits the condensed laser light and irradiates the side member 11 and the central member 12 as irradiation targets with the laser light, thereby melting and joining the side member 11 and the central member 12. The welding apparatus 42 includes a laser oscillator 43, a welding apparatus main body 46 that collects and emits laser light guided from the laser oscillator 43, and a gas supply unit that supplies CO ₂ gas when irradiating the laser light ( (Not shown). The CO ₂ gas prevents oxidation of the side member 11 and the central member 12. In FIG. 2, the illustration of the laser oscillator 43 is omitted to avoid complication of the drawing.

  A TIG welding (Tungsten Inert Gas welding) apparatus may be used instead of the laser welding apparatus. As is well known, TIG welding is one type of welding arc welding that uses an arc as a heat source, and is a type of inert gas arc welding that uses inert gas (inert gas) as a shielding gas and tungsten or a tungsten alloy as an electrode. is there. Laser welding is more preferable than TIG welding. Moreover, it is good also as hybrid welding which combined TIG welding and laser welding.

  A welding support roller 41 for supporting the side member 11 and the central member 12 on the circumferential surface is provided in the conveyance path between the side member 11 and the central member 12 so as to face the laser beam exit of the welding apparatus main body 46. is there. The rotation axis of the welding support roller 41 is parallel to the width direction Y of the side member 11 and the central member 12. The support position of the side member 11 and the central member 12 by the welding support roller 41 is set so that the side member 11 and the central member 12 while being supported by the peripheral surface of the welding support roller 41 are irradiated with laser light. It is preferable to do. That is, it is preferable to perform welding on the welding support roller 41. Thereby, the side member 11 and the central member 12 are stabilized in a state in which the side edges 11e and 12e are in contact with each other, and the laser beam can be reliably irradiated to the portion to be irradiated.

  The welding apparatus body 46 is preferably provided with a shift mechanism 50 for displacement in the width direction Y. A contact position Ps (see FIG. 5) where the side edge 11e of the side member 11 and the side edge 12e of the central member 12 are in contact with each other is detected on the upstream side of the welding device 42, and the detected contact position Ps (see FIG. 5) is detected. ) Position detecting means 47 is provided for sending the signal (1) to the controller 51. The position detection means 47 should just be distribute | arranged to the conveyance path vicinity from the butting position Ph to the welding apparatus 42 (for example, welding position Pw).

  The controller 51 obtains the displacement amount of the welding apparatus main body 46 in the width direction Y based on the sent signal of the contact position Ps (see FIG. 5), and sends the displacement amount signal to the shift mechanism 50. When the conveyance speed signal between the side member 11 and the central member 12 is input, the controller 51 sends a displacement timing signal together with a displacement timing signal to the displacement mechanism 50 to the displacement mechanism 50. The shift mechanism 50 changes the position of the welding apparatus main body 46 at a predetermined timing based on the received displacement amount and displacement timing signal. Thus, by changing the position of the welding apparatus main body 46 in the width direction Y, the irradiation position of the laser beam is controlled more precisely, and the side member 11 and the central member 12 are more reliably welded. In addition, the conveyance speed of the side member 11 and the central member 12 to the welding apparatus 42 in this embodiment is set as a range of 0.15 m / min or more and 20 m / min or less.

  As shown in FIG. 1, the welding unit 18 is more preferably provided with a chamber 52 that partitions the welding device main body 46 and the welding support roller 41 from the external space, and a cleaning device 55 that cleans the gas. In FIG. 2, the illustration of the chamber 52 and the cleaning device 55 is omitted to avoid complication of the drawing. The chamber 52 is provided with a first opening (not shown) for letting out the internal gas to the outside and a second opening (not shown) for guiding the gas cleaned by the cleaning device 55 to the inside. The first opening and the second opening are each connected to the cleaning device 55. The gas inside the chamber 52 is guided to the cleaning device 55 from the first opening, and the cleaning device 55 cleans the gas guided from the chamber 52 and sends it to the chamber 52 through the second opening. In this way, the internal gas of the chamber 52 is circulated with the cleaning device 55.

  By cleaning the internal gas of the chamber 52, the welding position Pw and its periphery are cleaned, and foreign matter and the like are prevented from being mixed into the welded portion 13w. Note that, by keeping the pressure inside the chamber 52 higher than the pressure in the external space, the inside of the chamber 52 can be reliably held in a clean state. Further, by setting the welding position Pw to a relatively high position with respect to the delivery unit 16, the butting unit 17, the heating unit 19, and the winding device 20, it is possible to further prevent foreign matters from being guided from these positions. it can.

  The cleanliness inside the chamber 52 is preferably, for example, class 1000 or less, more preferably class 100 or less, according to the US Federal Standard FED-STD-209D.

(Heating part)
The heating unit 19 is preferably provided on the downstream side of the welding unit 18. The heating part 19 will not be specifically limited if it heats the welding part 13w of the band member 13 obtained by welding so that it may become a fixed temperature range. There may be a case where stress due to distortion caused by welding remains inside the welded portion 13w and its periphery. The stress can be removed by heating the welded portion 13w and the periphery thereof by the heating unit 19. By removing the stress, deformation of the welded portion 13w can be suppressed even when the solution casting method is performed continuously for a long time.

  Although the temperature of the welding part 13w by the heating of the heating part 19 will not be specifically limited if it is the temperature from which stress is removed, For example, when the band member 13 consists of stainless steel, the temperature of the welding part 13w is 100 degreeC or more. It is preferably 200 ° C. or lower, and more preferably 120 ° C. or higher and 180 ° C. or lower.

  As the heating unit 19, for example, there is a blowing means. As shown in FIG. 1, the blowing means as the heating unit 19 includes a duct 56 that blows out a gas having a constant temperature, and a blower 57 that sends the gas to the duct 56 after controlling the temperature of the gas. In FIG. 2, the illustration of the duct 56 and the blower 57 is omitted to avoid complication of the drawing.

  The heating unit 19 may be provided on the opposite side of the welding support roller 41 as shown in FIG. 1 with respect to the conveyance path of the band member 13 or may be provided on the same side as the welding support roller 41.

  The band member 13 from which the stress has been removed is sent to the winding device 20 downstream of the heating unit 19 and wound up in a roll shape. In the winding device 20, a winding core for winding the band member 13 is set, and driving means for rotating the winding core in the circumferential direction is provided.

  The winding device 20 also functions as a welding tension control means for controlling the tension between the band member 13, the side member 11, and the central member 12 at the welding position Pw. Therefore, it is preferable to control the torque of the winding device 20 so that the tension between the band member 13, the side member 11, and the central member 12 at the welding position Pw is kept constant. Thereby, the welding part 13w can be made into a fixed state in a longitudinal direction.

  When starting welding, it is preferable to use the winding device 20 as follows, for example. First, the side member 11 and the central member 12 are set on the conveyance path from the delivery unit 16 to the winding device 20, and the respective ends of the side member 11 and the central member 12 are wound around the winding core of the winding device 20. Winding of the side member 11 and the central member 12 is started. Winding is started, the conveyance path between the side member 11 and the central member 12 is controlled, and the butting position Ph is held at a predetermined position. After the abutting position Ph between the side member 11 and the central member 12 is held constant, welding is started by the welding device 42.

(Prevents slippage)
It is preferable that the welding is performed while suppressing the displacement of the side member 11, the central member 12, and the band member 13. For example, instead of the welding unit 18, a welding unit 61 as shown in FIGS. 3 and 4 provided with a pressing device may be used. The welding unit 61 further includes a pressing device 62 in addition to the welding unit 18 shown in FIGS. In order to avoid complication of illustration, these illustrations are omitted in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS. 1 and 2 and description thereof is omitted. In the welding unit 61, the chamber 52 surrounds the pressing device 62 and the welding support roller 41 so as to partition from the external space.

  The pressing device 62 suppresses misalignment of the side member 11, the central member 12, and the band member 13 at the welding position Pw, and is welded by a pair of belts including a first belt 63 and a second belt 64. The side member 11, the central member 12, and the band member 13 on the support roller 41 are pressed.

  The first belt 63 and the second belt 64 are endless belts formed in an annular shape. The first belt 63 and the second belt 64 are wound around the circumferential surfaces of the fifth roller 67 to the seventh roller 69 so as to be aligned in the longitudinal directions of the fifth roller 67 to the seventh roller 69. At least one of the fifth roller 67 to the seventh roller 69 is a drive roller that rotates in the circumferential direction. Due to the rotation of the driving roller, the first belt 63 and the second belt 64 are conveyed while maintaining a conveyance path parallel to each other.

  The fifth roller 67 to the seventh roller 69 are arranged so that the rotation axis thereof is parallel to the rotation axis of the welding support roller 41.

  The fifth roller 67 to the seventh roller 69 are arranged in a region opposite to the side on which the fourth roller 29 and the welding support roller 41 are arranged with respect to the conveyance path between the side member 11 and the central member 12. . The fifth roller 67 is provided so as to face the conveyance path between the side member 11 and the central member 12 from the fourth roller 29 toward the welding support roller 41. The sixth roller 68 is provided so as to face the conveyance path between the side member 11 and the central member 12 from the welding support roller 41 toward the heating unit 19. The seventh roller 69 is appropriately arranged so as to determine the conveyance path of the first belt 63 and the second belt 64 from the sixth roller 68 to the fifth roller 67.

  The fifth roller 67 and the sixth roller 68 are the first belt 63 and the second belt 64 that are directed from the fifth roller 67 to the sixth roller 68, and the side member 11, the central member 12, and the band on the welding support roller 41. It arrange | positions so that it may convey so that the member 13 may be pressed. For example, when the side member 11 and the central member 12 on the welding support roller 41 are welded from above, the lower end of each of the fifth roller 67 and the sixth roller 68 is higher than the upper end of the welding support roller 41. Also, it is arranged to be in a low position.

  The fifth roller 67 and the sixth roller 68 are arranged so that the conveyance path of the first belt 63 faces the conveyance path between the side member 11 and the side portion 13s of the band member 13 formed from the side member 11, and The transport path of the second belt 64 is provided so as to face the transport path between the central member 12 and the central portion 13c of the band member 13 formed from the central member 12. Accordingly, the first belt 63 presses the side member 11 and the side portion 13s against the welding support roller 41, and the second belt 64 presses the center member 12 and the center portion 13c against the welding support roller 41, respectively.

  As described above, the first belt 63 and the second belt 64 are provided to face the welding support roller 41, respectively, so that the heights of the side member 11 and the central member 12 at the welding position Pw are equal. Press. The height of the side member 11 and the central member 12 is the height of the surface of each member 11 and 12. By pressing the side member 11 and the central member 12 so that the heights are equal to each other and performing welding in this state, the aspect of the welded portion 13w becomes more uniform in the longitudinal direction and welding is more reliably performed. Can be done.

  The longitudinal welding process will be described in more detail with reference to FIGS. The first belt 63 and the second belt 64 are conveyed in a state of being separated from each other. The conveyance path is set so that the welding position Pw passes through the gap between the first belt 63 and the second belt 64 for the first belt 63 and the second belt 64. Thereby, the contact position Ps at which the side edge 11e of the side member 11 and the side edge 12e of the central member 12 are in contact with each other passes through the gap between the first belt 63 and the second belt 64, as shown in FIG. Welding is performed between the first belt 63 and the second belt 64. In addition, illustration of the welding apparatus main body 46 is abbreviate | omitted in FIG.

  The distance D1 between the first belt 63 and the second belt 64 is preferably in the range of 6 mm to 12 mm. In the cross section in the width direction Y between the side member 11 and the central member 12, the distance D2 between the contact position Ps and the first belt 63 and the distance D3 between the contact position Ps and the second belt 64 are 3 mm or more and less than 6 mm, respectively. It is preferable to set it as the range.

  Instead of the pressing device 62, rollers (not shown) having a rotation axis parallel to the rotation axis of the welding support roller 41 may be arranged upstream and downstream of the welding device main body 46, respectively. In this case, the side member 11 and the central member 12 at the welding position Pw can be pressed by pressing the side member 11 and the central member 12 with one upstream roller and pressing the band member 13 with the other downstream. it can.

  As shown in FIG. 6, a weld bead 72 is formed at the contact position Ps and the periphery thereof by melting by the heat of the welding device 42. Heat is transmitted from the weld bead 72 to both sides, and a heat-affected region 73 is generated in each of the side member 11 and the central member 12 that is affected by heat in welding. The heat-affected area 73 may immediately show a different property from other areas that are not affected by heat or may show over time. For example, when a material having such a wide thermal effect is used as a casting support, the welded part 13w is deformed or the casting film is foamed when the solution casting method is continuously performed for a long time. And other harmful effects occur.

  Therefore, as shown in FIG. 5, in the peripheral region of the welding support roller 41, a high heat conduction portion made of a material having higher heat conductivity than the side member 11 and the central member 12 is in a passage region through which the contact position Ps passes. 71 is preferably formed. Thereby, the heat from the welding apparatus 42 (refer FIG. 3, FIG. 4) can be spread | diffused more quickly. In order to diffuse heat more quickly on the side of the welding support roller 41, the width of the heat affected area 73 between the side member 11 and the central member 12 can be made smaller or the depth of the heat affected area 73 can be made shallower.

  It is preferable that the width D4 of the passage region used as the high heat conducting portion 71 is in a range of 26 mm or more and 32 mm or less.

  Furthermore, it is more preferable that high heat conductive portions made of a material having higher thermal conductivity than the side member 11 and the central member 12 are formed on both surfaces of the first belt 63 and the second belt 64. Thereby, the magnitude | size of the heat affected zone 73 can be made small in the width direction or the thickness direction.

  It is preferable that the side edge 11e of the side member 11 and the side edge 12e of the central member 12 are in close contact with each other so that the gap is 0 (zero) at the welding position Pw. Therefore, it is preferable that the side member 11 and the central member 12 are formed in advance so as not to generate a gap when the side edges 11e and 12e are brought into contact with each other. Thereby, the band member without a space | gap in a welding part can be manufactured more reliably.

  The above-described longitudinal welding process may be only a continuous welding process in which welding is continuously performed in the longitudinal direction of the side member 11 and the central member 12, and in addition to this, intermittent welding in which welding is intermittently performed. A welding process may be performed. When intermittently welding, the side member 11 and the central member 12 that are continuously sent to the welding device 42 are welded intermittently. Such an intermittent welding process is preferably performed before the continuous welding process. In this case, in the intermittent welding process, first, the side member 11 and the central member 12 may be temporarily joined, and then joined over the entire longitudinal direction in the continuous welding process.

  When temporary joining is performed in the intermittent welding process and then joining is performed in the continuous welding process, the side member 11 and the central member 12 are guided to the welding unit 18 from the butt portion 17 (see FIGS. 1 and 2), and intermittently. Weld to. In addition, when the side member 11 and the central member 12 are provided with a surface corresponding to a casting surface when used as a subsequent casting support and a back surface corresponding to a non-casting surface, intermittent The welding in the welding process is preferably performed on the back surface. Then, the side member 11 and the central member 12 are conveyed so that a back surface may pass facing the welding apparatus main body 46 (refer FIG. 1).

  After performing an intermittent welding process, it guides to the winding device 20 and winds up. In addition, you may heat with the heating part 19 with respect to a welding part before winding. A temporary joining member (not shown) made up of the side member 11 and the central member 12 wound through the intermittent welding process is unwound by a feeding device (not shown) and sent to the welding unit 18 again. This feeding is performed so that the surface of the temporary welding member passes facing the welding apparatus main body 46 (see FIG. 1). The welding unit 18 performs continuous welding to obtain the band member 13. In place of this method, the two welding units 18 are arranged side by side relatively upstream and downstream, intermittent welding is performed by one upstream welding unit 18, and continuous welding is performed by the other downstream welding unit 18. May be implemented.

  When welding is performed, the weld bead 72 may be formed so as to be higher than the side member 11 and the central member 12. Therefore, as shown in FIG. 5, the welding support roller 41 used in the case where the first process of welding one surface in the longitudinal direction and the second process of welding the other surface in the longitudinal direction are performed as shown in FIG. Further, it is preferable that a groove 76 is formed in a passing region through which the contact position Ps passes on the peripheral surface of the welding support roller 41. It is good to carry out the 2nd process by conveying the side member 11 and the central member 12 so that the welding part formed from the welding beat 72 raised in the 1st process may pass this groove | channel 76. FIG. Thereby, the band member 13 that is smoother and has less residual stress can be obtained. Therefore, even when used in solution casting, it is possible to more reliably produce a film in which the band as a casting support is less deformed and changes in properties, the casting membrane does not foam, and the thickness is not uneven.

  The width D5 of the groove 76 is preferably in the range of 6 mm to 12 mm, and the depth D6 of the groove may be about 1 mm.

  In the above embodiment, the third roller 28 is used as means for adjusting the conveyance path of the side member 11 in the abutting portion 17, but instead of the third roller 28, a tapered roller 81 as shown in FIG. 7 may be used. The taper roller 81 is a roller having a circular cross section formed so that the diameter d continuously decreases gradually from one end to the other end. The diameter d gradually decreases gradually from one end to the other end at a constant rate. The taper roller 81 is arranged so that one end with a large diameter d faces the conveyance path of the central member 12 and the other end with a small diameter d faces the side opposite to the central member 12 (conveyance path side of the side member 11).

  The side member 11 being conveyed comes into contact with the taper roller 81, thereby changing the conveyance path to the direction of the arrow A toward the central member 12, and approaching the central member 12. Thereby, the side member 11 is reliably conveyed toward the butting position Ph (refer FIG. 1, FIG. 2).

  The taper roller 81 is preferably provided with driving means 82 that rotates in the circumferential direction. The rotating shaft is formed through the center of one end surface and the center of the other end surface. By conveying the side member 11 by the taper roller 81 rotated by the driving means 82, the side member comes closer to the central member 12 more effectively.

  Instead of the third roller 28, a clip 85 as gripping means as shown in FIG. 8 may be used. The clip 85 includes a clip body 86 opened in a U-shape and a pair of sandwiching pins 87 provided at the respective distal end portions of the clip body 86, and grips and holds the side member 11. The pinching pin 87 is provided so as to be movable between a pinching position for pinching the side member 11 and a retreating position for retreating from the pinching position. The clip 85 includes a moving mechanism 88 and is movable between a grip start position where gripping is started and a grip release position where gripping is released. The clip 85 is also movable in the width direction Y.

  The clip 85 grips the side member 11 when the pinching pin 87 moves to the pinching position at the gripping start position. The clip 85 is conveyed downstream while approaching the direction A toward the central member 12 with the side member 11 being gripped.

  The taper roller 81 and the clip 85 may be used to bring the central member 12 closer to the side member 11 in addition to being used to bring the side member 11 closer to the central member 12. In this case, the central member 12 may be supported or conveyed by the taper roller 81 and the clip 85.

  In the above embodiment, the both side members 11 are welded to the central member 12 at the same time. However, after the one side member 11 is welded to the central member 12, the other side member 11 may be welded to the central member 12. .

(band)
As shown in FIG. 9, a band 91 used as a casting support is an endless band formed into an annular shape. The band 91 is formed by welding one end and the other end in the longitudinal direction of the band member 13. The band member 13 for forming the band 91 may be cut to a predetermined length, or when the band member 13 is made from the side member 11 and the central member 12 that have been cut to a predetermined length in advance. The band 91 may be made as it is without cutting. The diameter of the pinhole in the weld is preferably less than 40 μm.

  The band member 13 is preferably cut in a direction crossing the width direction Y. More preferably, the cut direction is such that the angle formed with the width direction Y is in the range of approximately 5 ° to 15 °. The angle θ2 formed by the welded portion 91v in which the front end and the front end in the longitudinal direction of the band member 13 thus cut are welded and the width direction Y is approximately in the range of 5 ° to 15 °. As described above, in the annular welding process in which the long band member 13 is annular, the welding apparatus 42 used in the longitudinal welding process may be used, or other known welding apparatuses may be used.

  The band 91 manufactured by welding includes a side portion 91s formed from the side member 11 (see FIGS. 1 to 8) and a center portion 91c formed from the central member 12 (see FIGS. 1 to 8). The welded portion 91w of the side portion 91s and the central portion 91c is exposed on the front surface 91a and the back surface 91b. The welded portion 91w is a portion corresponding to the welded portion 13w. The linear welded portion 91 w is preferably provided so as to be parallel to the longitudinal direction of the band 91. The width of the band 91 thus obtained is in the range of 2000 mm to 3000 mm.

  The obtained band 91 is used for a solution casting facility after the surface is polished to a mirror surface. Next, a method for producing a film in a solution casting apparatus will be described below. The kind of polymer is not particularly limited, and a known polymer that can be formed into a film by solution casting may be used. In the following embodiments, a case where cellulose acylate is used as a polymer will be described as an example.

(Solution casting equipment)
As shown in FIG. 10, the solution casting apparatus 110 performs the casting apparatus 115 that creates the wet film 113 from the dope 112, the clip tenter 117 that obtains the film 116 by drying the wet film 113, and the wet film 113. A film drying device 118 and a winding device 119 for winding the film 116 around a winding core are provided.

(Casting device)
As shown in FIGS. 10 and 11, the casting apparatus 115 includes a casing 121 and a casting apparatus main body arranged in the casing 121. The casting apparatus main body includes a casting support unit, a partition unit, a casting unit, a film drying unit, and a peeling roller 122.

  The casting support unit includes horizontal drums 124 and 125, a band 91 spanned over the horizontal drums 124 and 125, and a band movement control unit 128 (see FIG. 12).

  The horizontal drum 124 includes a drive shaft 124a and a stainless steel drum main body 124b attached to the drive shaft 124a. The horizontal drum 125 includes a shaft 125a and a stainless steel drum body 125b that is attached to the shaft 125a. The peripheral surfaces of the drum bodies 124b and 125b are formed flat.

  The band 91 is obtained by connecting both ends of a band-shaped sheet material. The band 91 can be manufactured by the band manufacturing facility 10 (see FIG. 1) described above.

  The band 91 is preferably made of SUS316 having sufficient corrosion resistance and strength. The width of the band 91 is preferably 1.1 to 2.0 times the casting width of the dope 112, for example. The length of the band 91 is preferably 20 m or more and 200 m or less, for example. The thickness of the band 91 is preferably 0.5 mm to 2.5 mm, for example. Note that the thickness unevenness of the band 91 is preferably 0.5% or less with respect to the total thickness. Further, a surface 91a on which the cast film is formed (hereinafter referred to as a cast surface) 91a and a back surface 91b in contact with the drum main bodies 124b and 125b are formed flat. In particular, the casting surface 91a is preferably polished, and the surface roughness of the casting surface 91a is preferably 0.05 μm or less.

  As shown in FIG. 12, the band movement control unit 128 is for controlling the movement and temperature of the band 91, and includes a drive motor 128m, an axis shift unit 128s, a load cell 128lc, and a drum temperature adjustment unit 128d. And a band temperature controller 128b and a controller 128c.

  The drive motor 128m is connected to the drive shaft 124a. The controller 128c controls the driving motor 128m to rotate the drum body 124b at a predetermined speed. The band 91 circulates and moves in a predetermined direction as the drum body 124 b rotates, and the drum body 125 b rotates according to the movement of the band 91. Hereinafter, the moving direction of the band 91 is referred to as a Z1 direction, the width direction of the band 91 is referred to as a Z2 direction, and the vertical direction is referred to as a Z3 direction.

The moving speed V _91a of the casting surface 91a of the band 91 is preferably 150 m / min or less. If the moving speed V _91a exceeds 150 m / min, it becomes difficult to stably form the beads. The lower limit value of the moving speed V _91a may be determined in consideration of the target film productivity. The lower limit value of the moving speed V _91a is, for example, 10 m / min.

  The drive shaft 124a is between a tension application position where a predetermined moving tension is applied to the band 91 spanned over the drum bodies 124b and 125b, and a slack position where the band 91 spanned over the drum bodies 124b and 125b is slack. It is free to move. The shaft shift unit 128s can shift the drive shaft 124a between the tension application position and the slack position under the control of the controller 128c. The shaft shift unit 128s preferably shifts the drive shaft 124a while maintaining a state parallel to the shaft 125a.

  The load cell 128lc is attached to the drive shaft 124a. The load cell 128lc detects an external force received by the drive shaft 124a. The controller 128c reads the external force received by the drive shaft 124a from the load cell 128lc. Next, the controller 128 c controls the shaft shift unit 128 s so that the moving tension applied to the band 91 becomes a predetermined value based on the read external force and the value of the cross-sectional area of the built-in band 91. Thus, a uniform moving tension can be applied to the band 91 in the Z2 direction.

  The drum temperature adjustment unit 128d includes a drum temperature adjustment unit 128da attached to the horizontal drum 124 and a drum temperature adjustment unit 128db attached to the horizontal drum 125. The drum temperature control units 128da and 128db circulate the heat transfer medium adjusted to a desired temperature under the control of the controller 128c in the flow paths provided in the drum main bodies 124b and 125b, respectively. Due to the circulation of the heat transfer medium, the drum bodies 124b and 125b can be maintained at a desired temperature. It is preferable that the temperature of the casting surface 91a of the band 91, particularly the portion where the casting film is formed, is adjusted to be substantially constant within a range of 10 ° C to 40 ° C.

  The band temperature adjustment unit 128b will be described later.

  As shown in FIG. 11, the partition unit includes first to third seal members 131 to 133. The first to third seal members 131 to 133 are sequentially arranged in the casing 121 from the upstream side in the Z1 direction toward the downstream side. The first to third seal members 131 to 133 are provided so as to protrude from the inner wall surface of the casing 121, and the protruding end is close to the casting surface 91 a of the band 91. The area surrounded by the first to third seal members 131 to 133 in the casing 121, that is, the inner wall surface of the casing 121 and the casting surface 91a, is the casting chamber 121a from the upstream side toward the downstream side in the Z1 direction. The drying chamber 121b and the peeling chamber 121c are partitioned. And the airtightness of the casting chamber 121a is maintained by the 1st-2nd seal members 131-132. Moreover, the airtightness of the drying chamber 121b is maintained by the second to third seal members 132 to 133. The space | interval of the 1st-3rd seal members 131-133 and the casting surface 91a is 1.5 mm or more and 2.0 mm or less, for example.

(Casting room)
A casting unit that forms a casting film 141 from the dope 112 is disposed in the casting chamber 121a. The casting unit includes a casting die 142 and a decompressor 143. The casting die 142 has a dope outlet 142 a that flows out of the dope 112, and is disposed above the horizontal drum 124 so that the dope outlet 142 a is close to the band 91.

  The casting die 142 flows out the dope 112 from the dope outlet 142a toward the band 91. The dope 112 that flows out from the dope outlet 142a and reaches the casting surface 91a forms a bead. The dope 112 that has reached the casting surface 91a is caused to flow in the Z1 direction, thereby forming a belt-like casting film 141.

  The decompressor 143 is for decompressing the upstream side of the bead in the Z1 direction. The decompressor 143a is disposed upstream of the dope outlet 142a of the casting die 142 in the Z1 direction, and in the decompression chamber 143a. A decompression fan (not shown) for sucking the gas, and a suction pipe (not shown) connecting the decompression fan and the decompression chamber 143a.

(Drying room)
The drying chamber 121b is provided with a film drying unit for drying the cast film. The membrane drying unit includes a first dryer 151 and a second dryer 152 that supply predetermined drying air to the casting membrane 141, and a drying controller (not shown). The first dryer 151 to the second dryer 152 are sequentially provided from the upstream side toward the downstream side in the Z1 direction in the drying chamber 121b. The first dryer 151 is disposed above the band 91 that spans the horizontal drums 124 and 125. The second dryer 152 is disposed below the band 91 that spans the horizontal drums 124 and 125.

  The first dryer 151 includes a first air supply duct 151a and a first exhaust duct 151b. The first air supply duct 151a and the first exhaust duct 151b are sequentially provided from the upstream side in the Z1 direction toward the downstream side. The first air supply duct 151 a and the first exhaust duct 151 b are spaced apart from the band 91. The first air supply duct 151b is provided with a first air supply port through which the first drying air 151da is sent out. The first air supply opening that opens toward the downstream side in the Z1 direction extends from one end of the casting membrane 141 to the other end. The first exhaust duct 151a is provided with a first exhaust port for exhausting the first dry air 151da. The first exhaust opening that opens toward the upstream side in the Z1 direction extends from one end of the casting film 141 to the other end.

  The second dryer 152 includes a second exhaust duct 152a and a second air supply duct 152b. The second exhaust duct 152a and the second air supply duct 152b are sequentially provided from the upstream side in the Z1 direction toward the downstream side. The second exhaust duct 152a and the second air supply duct 152b are arranged separately from the band 91, respectively. The second exhaust duct 152a is provided with a second exhaust port for exhausting the second dry air 152da. The second exhaust opening that opens toward the downstream side in the Z1 direction extends from one end of the casting film 141 to the other end. The second air supply duct 152b is provided with a second air supply port through which the second drying air 152da is sent out. The second air supply port that opens toward the upstream side in the Z1 direction extends from one end of the casting membrane 141 to the other end.

  The drying controller independently adjusts the temperature and wind speed of the first drying air 151da and the second drying air 152da, and adjusts the temperature of the first drying air 151da and the second drying air 152da. A two-temperature controller (not shown), first and second blower fans (not shown) for adjusting the air volume of the first drying air 151da and the second drying air 152da, and a controller (not shown) are provided. The first to second temperature controllers and the first to second blower fans are provided in the ducts of the first dryer 151 to the second dryer 152. The controller controls the first and second temperature controllers and the first and second blower fans to independently adjust the temperature and the wind speed of the first drying air 151da and the second drying air 152da.

(Peeling room)
A peeling roller 122 is disposed in the peeling chamber 121c. The peeling roller 122 peels off the cast film 141 that has been peeled off from the band 91 to form a wet film 113, and sends the wet film 113 from an outlet 121co provided in the peeling chamber 121c. Thus, the horizontal drum 124 becomes a metal drum for casting and peeling.

  The casting apparatus 115 may be provided with a condensing device that condenses the solvent contained in the atmosphere in the casing 121 and a collecting device that collects the condensed solvent. Thereby, the density | concentration of the solvent contained in the atmosphere in the casing 121 can be kept in a fixed range.

  As shown in FIG. 13, a band support surface 124bs for supporting the back surface 91b of the band 91 is formed on the outer periphery of the drum main body 124b. A relief groove 124bd is provided in the band support surface 124bs. The escape groove 124bd extends in the circumferential direction and is formed in an annular shape. Similarly, a band support surface 125bs that supports the back surface 91b of the band 91 is formed on the outer peripheral portion of the drum body 125b. The band support surface 125bs is provided with a relief groove 125bd. The escape groove 125bd is formed in the same shape as the escape groove 124bd, extends in the circumferential direction, and is formed in an annular shape. The escape grooves 124bd and 125bd extending in the circumferential direction are not annular, that is, both ends of the escape grooves 124bd and 125bd are separated as long as the thickness unevenness failure and the shavings failure due to the welded portion can be suppressed. Shape may be sufficient.

  As shown in FIG. 14, the band 91 is wound around the drum body 124b so that the welded portion 91w is on the escape groove 124bd. Similarly, the band 91 is stretched over the drum body 125b so that the welded portion 91w is on the escape groove 125bd.

The width W _124bd of the escape groove 124bd may be the width of the welded portion 91w plus the meandering width of the band 91 when moved around the drums 124 and 125, for example, 20 mm or more. 40 mm or less. The depth D _124bd of the escape groove 124bd may be such that the distance CL1 from the bottom of the escape groove 124bd to the back surface 91b of the band 91 is within 0.1 mm, for example, 0.03 mm or more and 0.1 mm or less. is there. The end portion 124bE of the escape groove 124bd is preferably chamfered.

  When the band 91 meanders, a heat transfer failure to the band 91 occurs when the distance between the bottom part 124bb of the escape groove 124bd and the band 91 increases, and when the distance between the bottom part 124bb and the band 91 decreases, the contact with the welded part 91w occurs. The problem arises. Therefore, the bottom 124bb of the escape groove 124bd is preferably flat, that is, parallel to the band support surface 124bs. Since the bottom part 124bb of the escape groove 124bd is parallel to the band support surface 124bs, even when the band 91 meanders, the distance between the bottom part 124bb and the band 91 can be kept constant.

(Band temperature control section)
As shown in FIGS. 11 and 12, the band temperature adjustment unit 128b includes a band surface cooler 161 disposed in the peeling chamber 121c and a band back surface cooler 162 disposed in the drying chamber 121b.

  As shown in FIGS. 14 and 15, the band surface cooler 161 is downstream in the Z1 direction from the position PP where the casting film 141 is peeled off (hereinafter referred to as a peeling position), and in the Z2 direction, it escapes. It is provided in a portion facing the groove 124bd, that is, in the vicinity of the weld portion 91w. Here, the peeling position PP is set to a part of the band 91 supported by the peeling metal drum, that is, the horizontal drum 124.

  The band surface cooler 161 includes a temperature adjusting unit 161t that adjusts the temperature of the cooling gas 161a, a cooling nozzle 161n that sends out the cooling gas 161a, and a cooling gas 161a that is sent out from the cooling nozzle 161n on the casting surface 91a side. A cooling nozzle position adjusting unit 161s for adjusting the position of the cooling nozzle 161n is provided so as to correspond to 91w.

  As shown in FIGS. 15 and 16, the band back surface cooler 162 is a portion of the band 91 that moves so as to approach the horizontal drum 124 in the Z1 direction, and faces the escape groove 124bd in the Z2 direction. It is provided in the vicinity of the portion, that is, the welded portion 91w.

  Similarly to the band surface cooler 161, the band back surface cooler 162 includes a temperature adjustment unit 162t that adjusts the temperature of the cooling gas 162a, a cooling nozzle 162n that sends out the cooling gas 162a, and a cooling gas 162a that is sent out from the cooling nozzle 162n. Is provided with a cooling nozzle position adjusting unit 162s for adjusting the position of the cooling nozzle 162n so as to correspond to the welded portion 91w on the back surface 91b side.

  Returning to FIG. 10, a plurality of support rollers 171 that support the wet film 113 are arranged in a transition portion between the casting device 115 and the clip tenter 117. The support roller 171 is rotated around an axis by a motor (not shown). The support roller 171 supports the wet film 113 sent out from the casting device 115 and guides it to the clip tenter 117. In addition, although the case where the two support rollers 171 are arranged in the transition part is shown, the present invention is not limited to this, and one or three or more support rollers 171 may be arranged in the transition part. Further, the support roller 171 may be a free roller.

  The clip tenter 117 has a number of clips that grip both side edges of the wet film 113 in the width direction, and these clips move on the stretching track. Dry air is sent to the wet film 113 held by the clip, and the wet film 113 is subjected to a drying process along with a stretching process in the width direction.

  An ear clip device 172 is provided between the clip tenter 117 and the film drying device 118. At both ends in the width direction of the film 116 sent to the ear-cutting device 172, grip marks formed by clips are formed. The ear opener 172 cuts off both end portions having the grip marks. This separated part is sequentially sent to a cut blower (not shown) and a crusher (not shown) by air blowing, cut into small pieces, and reused as a raw material such as a dope.

  The film drying device 118 includes a casing having a conveyance path for the film 116, a plurality of rollers 118a that form the conveyance path for the film 116, and an air conditioner (not shown) that adjusts the temperature and humidity of the atmosphere in the casing. . The film 116 introduced into the casing is conveyed while being wound around a plurality of rollers 118a. By adjusting the temperature and humidity of the atmosphere, the remaining solvent evaporates from the film 116 conveyed in the casing. Further, an adsorption recovery device that recovers the solvent evaporated from the film 116 by adsorption is connected to the film drying device 118.

  Between the film drying device 118 and the winding device 119, a cooling chamber 173, a charge removal bar (not shown), a knurling roller 174, and an ear-cutting device (not shown) are provided in this order from the upstream side. The cooling chamber 173 cools the film 116 until the temperature of the film 116 reaches substantially room temperature. The neutralization bar is sent out from the cooling chamber 173 and performs a neutralization process for removing electricity from the charged film 116. The knurling roller 174 applies a winding knurling to both ends of the film 116 in the width direction. The edge-cutting device cuts both ends of the film 116 in the width direction so that knurling remains at both ends of the cut film 116 in the width direction.

  The winding device 119 includes a press roller 119a and a winding core 119b. The film 116 sent to the winding device 119 is wound around the winding core 119b while being pressed by the press roller 119a, and becomes a roll.

  Next, the operation of the present invention will be described. As shown in FIG. 11, the controller 128c rotates the horizontal drum 124 via the drive motor 128m. As a result, the band 91 sequentially circulates through the chambers 121a to 121c.

(Film formation process)
In the casting chamber 121a, a casting process for forming a casting film 141 made of the dope 112 on the band 91 is performed. The casting die 142 continuously flows out the dope 112 from the dope outlet 142a. The dope 112 that has flowed out forms a bead from the casting die 142 to the band 91, and is spread on the band 91. Thus, the casting film 141 made of the dope 112 is formed on the band 91.

  The decompressor 143 can create a state where the pressure on the upstream side of the bead in the Z1 direction is lower than the pressure on the downstream side of the bead in the Z1 direction. The pressure difference ΔP between the bead Z1 direction upstream side and the Z1 direction downstream side is preferably 10 Pa or more and 2000 Pa or less.

(Film drying process)
In the drying chamber 121b, a drying process is performed in which a predetermined drying air is applied to the casting film 141 to evaporate the solvent from the casting film 141. The film drying process is performed until the cast film 141 is in a state where it can be conveyed independently. In the film drying process, the first film drying process and the second film drying process are sequentially performed.

  In the first film drying step, the solvent is evaporated from the casting film 141 until a dry layer is formed on the surface layer of the casting film 141. The first dryer 151 sends out the first drying air 151da from the first air supply port.

  By this first film drying step, the cast film 141 has a dry layer and a wet layer. The dry layer is a portion that is generated on the surface side of the casting film 141 and is more dried than the wet layer positioned on the band 91 side of the dry layer. That is, the solvent content of the dry layer is lower than that of the wet layer. Further, the surface of the dry layer is formed smoothly. When a predetermined drying process is performed on the cast film 141 having the dry layer, the surface of the dry layer becomes the surface of the obtained cast film 141. Therefore, a cast film 141 having a smooth surface can be obtained by forming a dry layer in the cast film 141 immediately after formation.

  Here, the content of the solvent indicates the amount of the solvent contained in the cast film or each film on a dry basis, a sample is taken from the target film, the weight of this sample is x, the sample When the weight after drying is y, {(xy) / y} × 100.

  The temperature of the first drying air 151da is preferably 30 ° C. or higher and 80 ° C. or lower. Moreover, it is preferable that the wind speed of 1st drying wind 151da is 5 m / sec or more and 25 m / sec or less.

  In the second film drying step, the solvent is evaporated from the casting film 141 using the second drying air 152da until the film can be conveyed independently. The second dryer 152 causes the second drying air 152da to flow along the film surface of the casting film 141 from the downstream side in the Z1 direction toward the upstream side. In this way, by causing the second drying air 152da to flow in the direction opposite to the Z1 direction, the evaporation of the solvent is promoted as compared with the case of flowing in the Z1 direction. It is preferable to perform a 2nd film | membrane drying process with respect to the casting film | membrane 141 whose content of a solvent is 20 mass% or more and 150 mass% or less. The temperature of the second drying air 152da is preferably 40 ° C. or higher and 80 ° C. or lower. Moreover, it is preferable that the wind speed of 2nd drying wind 152da is 5 m / sec or more and 20 m / sec or less.

(Peeling process)
In the peeling chamber 121c, a peeling process for peeling the cast film 141 that has been peeled off from the band 91 is performed. The peeling roller 122 peels off the casting film 141 in a peelable state from the band 91 to form a wet film 113, and sends the wet film 113 from an outlet 121CO provided in the peeling chamber 121c. It is preferable to perform a peeling process with respect to the cast film 141 whose solvent content is 20 mass% or more and 80 mass% or less.

  After the band 91 is fed out of the peeling chamber 121c, the band 91 is again introduced into the casting chamber 121a.

  The band 91 having the welded portion 91w is likely to warp from the central portion 91c (see FIG. 9) to the side portion 91s (see FIG. 9). When the band 91 is warped, a part of the band 91 is lifted from the horizontal drums 124 and 125, resulting in a foaming failure, a non-peeling failure, and a film thickness unevenness failure. The floating amount of the band 91 in the horizontal drums 124 and 125 decreases as the vertical stress N acting on the band 91 wound around the horizontal drums 124 and 125 increases. By utilizing this property, a floating amount reduction process for decreasing the floating amount CL by increasing the vertical stress N may be performed.

Here, when Dr is the radius of the horizontal drum, T is the moving tension of the band, and TH is the thickness of the band, the vertical stress N acting on the band wound around the horizontal drum is expressed by the following equation.
N = TH × T / Dr

Note that when the radius Dr of the horizontal drum 124 and 125 1000 mm, thickness TH of the band is 1.6 mm, the moving tension applied to the band 91 is, for ^{example, 50N / mm 2 ~70N / mm 2} .

  When the solution casting method using the band 91 having the welded portion 91w is continuously performed for a long time, a shaving powder failure or a thickness unevenness failure due to the welded portion 91w occurs. When the solution casting method is continuously performed for a long time, the welded portion 91w protrudes from the back surface 91b.

  Here, when the solution casting method is continuously performed for a long time, the cause that the welded portion 91w protrudes from the back surface 91b is presumed to be a phase transformation caused by the residual stress of the welded portion 91w.

  And if the band 91 is moved in the state which the welding part 91w protruded from the back surface 91b, the welding part 91w and the outer peripheral part of drum main body 124b, 125b will contact. When this contact is repeated on the back surface 91b, the welded portion 91w on the casting surface 91a is deformed into a concave shape over time. If the solution casting method is performed in this state, the trace of the welded portion 91w remains as uneven thickness on the film 116. If the film 116 having this thickness unevenness is wound on the winding core 119b as it is, the marks of the welded portion 91w are overlapped to form a black belt and appear on the film roll (hereinafter referred to as black belt failure). In addition, when the solution casting method is performed in a state where the welded portion 91w protrudes from the back surface 91b, a shaving powder failure occurs due to friction between the welded portion 91w and the outer peripheral portions of the drum main bodies 124b and 125b.

  In the present invention, the band 91 is wound around the drum body 124b so that the escape groove 124bd is provided on the band support surface 124bs of the drum body 124b, and the weld 91w is positioned on the escape groove 124bd. It does not contact the main body 124b. Similarly, since the band 91 is wound around the drum main body 125b so that the welded portion 91w is positioned on the escape groove 125bd, the welded portion 91w does not contact the drum main body 125b. For this reason, it becomes possible to suppress thickness unevenness failure and shaving powder failure.

  Moreover, the temperature of the band 91 which passed through the film | membrane drying process is high compared with before the film | membrane drying process introduction | transduction by contact with each drying wind. When the film forming process is performed using the band 91 in a high temperature state, the dope may be foamed. According to the drum temperature adjustment unit 128da, the drum main body 124b can be cooled so that the band 91 is lower than the foaming temperature of the dope. By cooling the drum body 124b, the temperature of the portion of the band 91 that directly contacts the drum body 124b can be made lower than the foaming temperature of the dope.

  However, the portion of the band 91 that does not directly contact the drum main body 124b, that is, the portion that faces the escape groove 124bd is not sufficiently cooled. If the cooling is insufficient, foaming of the dope occurs.

  As shown in FIG. 14, since the band surface cooler 161 can apply the cooling gas 161a to the portion facing the escape groove 124bd using the cooling nozzle 161n, the drum body temperature controller 128da cools the drum body 124b. We can make up for the shortage. Therefore, the film 116 can be efficiently manufactured while more reliably suppressing the foaming of the dope.

  From the viewpoint of production efficiency, it is preferable that the timing of performing the peeling step is higher in the solvent content of the cast film. However, if a peeling process is performed on a cast film having a high solvent content, a remaining failure is likely to occur. Therefore, it is preferable to cool the cast film immediately before the peeling step. By cooling the drum main body 124b using the drum temperature control unit 128da, it is possible to cool the casting film immediately before the peeling step. By cooling the drum body 124b, the temperature of the portion of the band 91 that directly contacts the drum body 124b can be made lower than the foaming temperature of the dope.

  However, the portion of the band 91 that does not directly contact the drum main body 124b, that is, the portion that faces the escape groove 124bd is not sufficiently cooled. And, if the cooling is insufficient, a non-peeling failure will occur.

  As shown in FIG. 16, the band back surface cooler 162 can apply the cooling gas 162a to the portion facing the escape groove 124bd by using the cooling nozzle 162n, so that the drum main body 124b is cooled by the drum temperature adjustment unit 128da. We can make up for the shortage. Therefore, it is possible to efficiently manufacture the film 116 while more reliably suppressing the remaining peeling failure.

  The setting position of the band surface cooler 161 in the Z1 direction may be either the separation chamber 121c or the casting chamber 121a as long as it is between the separation position PP and the arrival position CP. Here, the reaching position CP is set to a portion of the band 91 supported by the metal drum for casting, that is, the horizontal drum 124 (see FIGS. 11 and 15). Thus, the process of cooling the band 91 using the band surface cooler 161 may be performed between the peeling process and the next film forming process.

  In the above embodiment, the stainless steel band 91 is used, but a metal band 91 may be used. Similarly, although the stainless steel horizontal drums 124 and 125 are used, metal horizontal drums 124 and 125 may be used.

  Instead of applying the cooling gas 161a to the welded portion 91w on the casting surface 91a side using the band surface cooler 161, the solvent is applied to the welded portion 91w on the casting surface 91a side, and then the applied solvent is evaporated. Or you may roll in the state which made the cooled roller contact the welding part 91w by the side of the casting surface 91a. Similarly, instead of applying the cooling gas 162a to the welded portion 91w on the back surface 91b side using the band back surface cooler 162, the solvent is applied to the welded portion 91w on the back surface 91b side, and then the applied solvent is evaporated. Alternatively, the roller may be rolled in a state where the cooled roller is in contact with the welded portion 91w on the back surface 91b side. When the band 91 is cooled using a band surface cooler or a band back surface cooler, a solvent contained in the dope may be applied to the band 91.

  Although the installation position of the casting die 142 is set above the horizontal drum 124, the present invention is not limited to this. When the seal members 131 to 132 are provided so as to be close to the portion of the band 91 wound around the horizontal drum 125, the installation position of the casting die 142 may be set above the horizontal drum 125. In this case, the horizontal drum 125 is a casting metal drum, and the horizontal drum 124 is a peeling metal drum.

  Further, when the support drum for supporting the band 91 is provided between the horizontal drums 124 and 125 and the seal members 131 to 132 are provided so as to be close to the portion of the band 91 supported by the support drum, The installation position may be above the support drum. In this case, the support drum is a casting metal drum, and the horizontal drum 124 is a peeling metal drum.

  The film 116 obtained by the present invention can be used particularly for a retardation film or a polarizing plate protective film.

  The width of the film 116 is preferably 600 mm or more, and more preferably 1400 mm or more and 2500 mm or less. The present invention is also effective when the width of the film 116 is larger than 2500 mm. The film 116 preferably has a thickness of 20 μm or more and 80 μm or less.

  The in-plane retardation Re of the film 116 is preferably 20 nm to 300 nm, and the thickness direction retardation Rth of the film 116 is preferably −100 nm to 300 nm.

The method for measuring the in-plane retardation Re is as follows. In-plane retardation Re is a letter obtained by conditioning a sample film at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and measuring it from the vertical direction at 632.8 nm with an automatic birefringence meter (KOBRA21DH Oji Scientific Co., Ltd.). The foundation value was used. Re is expressed by the following equation.
Re = | n1-n2 | × d
n1 is the refractive index of the slow axis, n2 is the refractive index of the fast axis 2, and d is the thickness (film thickness) of the film.

The measuring method of the thickness direction retardation Rth is as follows. The sample film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and measured in the same manner while tilting the film surface with an ellipsometer (M150 manufactured by JASCO Corporation) measuring 632.8 nm from the vertical direction. It calculated according to the following formula from the extrapolated value of the retardation value.
Rth = {(n1 + n2) / 2−n3} × d
n3 represents the refractive index in the thickness direction.

(polymer)
In the said embodiment, the polymer used as the raw material of a polymer film is not specifically limited, For example, there exist a cellulose acylate, cyclic polyolefin, etc.

(Cellulose acylate)
Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more kinds of acyl groups are used, it is preferable that one of them is an acetyl group. The ratio in which the hydroxyl group of cellulose is esterified with carboxylic acid, that is, the substitution degree of the acyl group satisfies all of the following formulas (I) to (III) is preferable. In the following formulas (I) to (III), A and B represent the substitution degree of the acyl group, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 to 22 carbon atoms. It is. In addition, it is preferable that 90 weight% or more of a triacetyl cellulose (TAC) is 0.1 mm-4 mm particle | grains.
(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 acyl group is more preferably 2.20 or more and 2.90 or less, and particularly preferably 2.40 or more and 2.88 or less. Further, the substitution degree B of the acyl group having 3 to 22 carbon atoms is more preferably 0.30 or more, and particularly preferably 0.5 or more.

  Cellulose, which is a raw material for cellulose acylate, may be obtained from either linter or pulp.

  The acyl group having 2 or more carbon atoms of the cellulose acylate of the present invention may be an aliphatic group or an aryl group and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include propionyl, butanoyl, pentanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl , Naphthylcarbonyl, cinnamoyl group and the like. Among these, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are more preferable, and propionyl and butanoyl are particularly preferable.

(solvent)
Solvents for preparing the dope include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol, Diethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (eg, tetrahydrofuran, methyl cellosolve, etc.). In the present invention, the dope means a polymer solution or dispersion obtained by dissolving or dispersing a polymer in a solvent.

  Among these, halogenated hydrocarbons having 1 to 7 carbon atoms are preferably used, and dichloromethane is most preferably used. In addition to dichloromethane, one kind of alcohol having 1 to 5 carbon atoms is used from the viewpoint of physical properties such as solubility of polymer, peelability from cast film support, mechanical strength of film and optical properties of film. It is preferable to mix several kinds. The content of the alcohol is preferably 2% by weight to 25% by weight and more preferably 5% by weight to 20% by weight with respect to the whole solvent. 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.

  By the way, recently, for the purpose of minimizing the influence on the environment, studies have been conducted on the solvent composition when dichloromethane is not used. For this purpose, ethers having 4 to 12 carbon atoms, carbon atoms A ketone having 3 to 12 carbon atoms, an ester having 3 to 12 carbon atoms, and an alcohol having 1 to 12 carbon atoms are preferably used. These may be used in combination 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. A compound having two or more functional groups of ether, ketone, ester, and alcohol (that is, —O—, —CO—, —COO—, and —OH) can also be used as the solvent.

  The details of cellulose acylate are described in paragraphs [0140] to [0195] of JP-A-2005-104148. These descriptions are also applicable to the present invention. The same applies to additives such as solvents and plasticizers, deterioration inhibitors, ultraviolet absorbers (UV agents), optical anisotropy control agents, retardation control agents, dyes, matting agents, release agents, and release accelerators. JP-A-2005-104148 describes in detail in paragraphs [0196] to [0516].

  Although the solution casting method has been described in the above embodiment, the present invention is also applicable to a method of forming a coating film by applying (casting) a liquid onto a support.

  In order to confirm the effect of the present invention below, Experiments 1 to 4 were performed. The details of each experiment will be described in Experiment 1. For Experiments 2 to 4, only the conditions different from Experiment 1 are shown.

(Experiment 1)
Using the band 91 in which the casting surface 91a and the back surface 91b were subjected to a predetermined polishing treatment, the solution film-forming facility 110 (see FIG. 10) was continuously performed for 700 hours to produce the film 116 from the dope 112. As the casting support unit, horizontal drums 124 and 125, a band 91, and a band movement control unit 128 as shown in FIG. 12 were used. The maximum distance CL1 (see FIG. 14) between the bottom of the escape groove 124bd and the back surface 91b of the band 91 was 0.1 mm. The temperature of the drum main body 124b was adjusted to 10 ° C., and the temperature of the drum main body 125b was adjusted to 30 ° C. by the drum temperature control units 128da and 128db. The moving tension T1 applied to the band 91 was 60 N / mm ² . The band temperature adjustment unit 128b is not used.

(Experiment 2)
A film 116 was produced in the same manner as in Experiment 1 except that CL1 was the value shown in Table 1 and that the band back surface cooler 162 was used as the band temperature adjustment unit 128b. The temperature of the cooling gas 162a was 5 ° C., and the wind speed of the cooling gas 162a was 20 m / sec.

(Experiment 3)
A film 116 was produced in the same manner as in Experiment 1, except that CL1 was the value shown in Table 1 and that the band surface cooler 161 was used as the band temperature adjustment unit 128b. The temperature of the cooling gas 161a was 5 ° C., and the wind speed of the cooling gas 161a was 20 m / sec.

(Experiment 4)
A film 116 was manufactured in the same manner as in Experiment 1 except that a horizontal drum having no escape groove and a flat entire peripheral surface was used in place of the horizontal drums 124 and 125.

  (Evaluation)

  The films obtained in Experiment 1 to Experiment 4 were evaluated as follows.

1. Evaluation of shavings failure The presence of shavings failure was investigated.
○: No cutting dust failure occurred.
X: A shaving powder failure occurred.

2. Evaluation of thickness unevenness in the trace of the welded portion In the following procedure, it was examined whether or not the trace of the welded portion remained as the thickness unevenness. A sample film was cut out from the film before being wound around the winding core by the winding device 119. Ten cut sample films were stacked. Then, when light was transmitted through the ten sample films, the shadow appearing on the surface of the sample film was visually observed. If no shadow is observed in the part of the sample film formed in the welded part, (○), if the shadow is observed in the part of the sample film formed in the welded part, it is not so In this case, it was (x).

  The evaluation results of Experiments 1 to 4 are shown in Table 1. In Table 1, the numbers assigned to the evaluation results represent the numbers assigned to the evaluation items.

DESCRIPTION OF SYMBOLS 110 Solution casting apparatus 115 Casting apparatus 91 Casting band 141 Casting film 124, 125 Horizontal drum 124bs, 125bs Band support surface 124bd, 125bd Escape groove 161 Band surface cooler 162 Band back surface cooler

Claims (7)

Is rotatably supported, a metal endless band having a weld extending in the longitudinal direction and supported by the peripheral surface, gold genus groove for escape from the weld is extended in the circumferential direction on the peripheral surface Drums ,
The endless band wound around the metal drum so that the weld is positioned on the groove, and moved by rotation of the metal drum;
A casting die for flowing a dope containing a polymer and a solvent toward the surface of the endless band;
A film drier that applies heating air to a cast film formed on the surface and made of the outflowed dope, and evaporates the solvent from the cast film;
A peeling machine according to the wet film the casting film is peeled off from the endless band supported portion to the metal drum for peeling of the endless band,
A peeling drum cooler for cooling the metal drum for peeling;
Casting device characterized in that a band back surface coolers for cooling the welded portion of the endless band moves closer to the metal drum for the release from the back side. The dope flowing out of the casting die reaches a portion of the endless band supported by the metal drum for casting,
A casting drum cooler for cooling the casting metal drum;
A band surface that is provided between the position where the dope reaches and the position where the casting film is peeled off in the endless band, and cools the welded part supported by the metal drum for casting from the surface side. casting apparatus according to claim 1, characterized in that a cooling machine. Is rotatably supported, a metal endless band having a weld extending in the longitudinal direction and supported by the peripheral surface, gold genus groove for escape from the weld is extended in the circumferential direction on the peripheral surface Drums ,
The endless band wound around the metal drum so that the weld is positioned on the groove, and moved by rotation of the metal drum;
A casting die that causes a dope containing a polymer and a solvent to flow toward the surface of the endless band, and reaches a portion of the endless band supported by the metal drum for casting;
A film drier that applies heating air to a cast film formed on the surface and made of the outflowed dope, and evaporates the solvent from the cast film;
A peeling machine for peeling the casting film from the endless band to form a wet film;
A casting drum cooler for cooling the casting metal drum;
A band surface that is provided between the position where the dope reaches and the position where the casting film is peeled off in the endless band, and cools the welded part supported by the metal drum for casting from the surface side. you wherein casting apparatus further comprising a cooler. The casting apparatus according to any one of claims 1 to 3, wherein the groove is formed in an annular shape . The casting apparatus according to any one of claims 1 to 4, wherein a bottom of the groove is flat . A method for forming a cast film, comprising: forming the cast film on a surface of the endless band using the casting apparatus according to any one of claims 1 to 5 . A casting apparatus according to any one of claims 1 to 5 , wherein the casting film is formed on a surface of the endless band, and the casting film is peeled from the endless band to form a film. A solution casting method characterized by the above.

Images