JP2009078490A - Water screen former of resin film manufacturing device, and film manufacturing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a uniform water screen by uniformly blowing wet air to the surface of a drum. <P>SOLUTION: This water screen former for forming a water screen on the surface of a rotary casting drum is attached to a resin film manufacturing device which manufactures a resin film by supplying a sheet-like molten resin to the surface of the rotary casting drum. The water screen former comprises (1) a former body which is arranged adjacently to the surface of the casting drum and has a chamber openable to the face side of the casting drum, (2) a wet air jetting means for spewing the wet air to the chamber of the former body, and (3) an opening part and a regulating valve arranged for uniformly spewing the wet air to the surface of the casting drum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water film forming apparatus, and more particularly to a water film forming apparatus used in a resin film manufacturing apparatus for manufacturing a resin film by supplying a sheet-like molten resin onto a rotating drum.

  As a method for producing a resin film at high speed, there is a method in which a thin film of water is formed on the surface of a rotating body (for example, a casting drum), and a molten resin is supplied to the surface of the casting drum through this water film to produce a resin film. Are known. An apparatus for carrying out this type of manufacturing method generally includes a casting drum, a water film forming part for forming a water film on the surface of the casting drum, and a sheet-like melt on the casting drum on which the water film is formed. A resin supply unit for extruding the resin and a water film removing unit for removing the water film on the surface of the casting drum are provided.

  In such an apparatus, the presence of a water film between the resin film and the casting drum surface eliminates the air accompanying the resin film and greatly suppresses the generation of microbubbles that are likely to form on the resin film surface. It is done. As a result, the production speed can be greatly increased, and technical proposals have already been made.

  For example, Patent Document 1 is an apparatus for forming a water film on the surface of a casting drum, and is a technique for attaching a mesh member for the purpose of uniformly diffusing indoor humid air. The proposal is diffused by passing moist air through the mesh member, but the effect is limited. The reason is that the amount of wet air from the jet port varies in the drum width direction. Usually, the amount of ejection near the supply port tends to be larger than that of the discharge portion, and the inclination tends to occur with respect to the width direction. For this reason, the amount of damp air is adjusted to adjust the variation, but this is not sufficient.

  Further, Patent Document 2 discloses that in a device that forms a water film on a casting drum by dew condensation on the casting drum, a sub-humid air blowing device is attached separately from the main wet air blowing device. However, since the amount of wet air from the jet port varies in the width direction of the drum, the effect of making the water film uniform is limited as described above.

Further, Patent Document 3 manufactures humid air by setting the hot water temperature in the sealed container to 81 ° C. or higher and 90 ° C. or lower in the humid air generator, and passing the air through the hot water. Even in this technology, the effect is limited. The reason is that the amount of wet air from the jet outlet varies in the width direction of the drum as described above. Unless the variation is eliminated in the width direction, a fundamental solution cannot be achieved.
Japanese Patent Laid-Open No. 06-071663 Japanese Patent Laid-Open No. 06-071665 Japanese Patent Laid-Open No. 06-071667

  In the conventional resin film manufacturing apparatus, the casting drum is cooled, and humid air is ejected from the water film forming section. This moist air hits the surface of the casting drum to cause condensation, thereby forming a water film on the surface of the casting drum. At this time, it is important to form a water film having a uniform predetermined thickness on the surface of the casting drum. For example, when the thickness of the water film is locally thin, the surface tension of this part becomes strong, and when the manufactured resin film is separated from the casting drum, the part is difficult to peel off, and the film may be cut off. is there.

  Therefore, when the humid air is ejected from the water film forming portion to the casting drum surface, it is important that the humid air uniformly contacts over a predetermined area of the drum surface. An object of the present invention is to provide a water film forming apparatus for a resin film manufacturing apparatus capable of uniformly applying wet air to a drum surface and forming a water film having a uniform desired thickness on the drum surface. .

  A water film forming apparatus according to the present invention is provided in a resin film manufacturing apparatus for manufacturing a resin film by supplying a molten resin in a sheet form onto a rotating casting drum, and an apparatus for forming a water film on the surface of the casting drum It is. It is equipped with a device main body, a pipe as a humid air ejection means, and an adjustment valve that adjusts the opening and the opening amount at the end of the pipe, and appropriately adjusts the flow rate of the humid air in the opening and the discharge amount of the adjustment valve. By doing so, the object of the present invention could be achieved.

  In the present invention, a device main body, a pipe as a humid air ejecting means, and an adjustment valve for adjusting the opening and the opening amount at the end of the pipe are provided, and the flow rate of the humid air in the opening and the discharge amount of the adjustment valve The water film having a uniform thickness can be formed by appropriately adjusting. By being able to form a uniform water film on the drum surface, it is possible to improve the peeling performance when the film leaves the drum.

  In the water film forming apparatus of the resin film manufacturing apparatus according to the present invention, humid air is jetted into the interior of the apparatus main body. It is equipped with a device main body, a pipe as a humid air ejection means, and an adjustment valve that adjusts the opening and the opening amount at the end of the pipe, and appropriately adjusts the flow rate of the humid air at the opening and the discharge amount of the adjustment valve. By doing so, a water film having a uniform thickness can be formed.

  FIG. 1 shows a resin film manufacturing apparatus according to an embodiment of the present invention. In the figure, the resin film manufacturing apparatus is mainly composed of a film manufacturing section 1, a film stretching section 2, and a winding section 3. The film manufacturing unit 1 includes a casting drum 4, a resin supply device 5, a static electricity application device 6, a water film formation device 7, and three wet air generation devices 80 (only one is shown in the figure) And a film feeder 8.

  The casting drum 4 is a cylindrical member having a smooth outer peripheral surface, and can be rotated counterclockwise by a driving device (not shown). The casting drum 4 has a built-in cold water pipe (not shown) for circulating the cooling water to cool the inner peripheral surface. The resin supply device 5 has a base (not shown) disposed above the casting drum 4 and extending in parallel with the axis of the casting drum 4. From this die, a sheet-like molten resin 5 a having a constant thickness can be supplied onto the casting drum 4.

  The static electricity application device 6 is disposed slightly apart from the outer peripheral surface of the casting drum 4 on the left side of the resin supply device 5 in the figure. The static electricity applying device 6 has a static electricity applying wire 6 a extending in parallel with the axis of the casting drum 4. A voltage applying device (not shown) is connected to the static electricity applying wire 6a so that a high voltage can be applied.

  The water film forming device 7 is disposed on the right side of the resin supply device 5 in the figure, and can be brought into contact with and separated from the casting drum 4 by the retracting device 9. Here, the details of the water film forming device 7 and the retracting device 9 will be described with reference to FIGS. The water film forming apparatus 7 is configured in a unit shape integrally including a water film forming part 19 and a water film removing part 20 provided on the film feeding apparatus 8 side of the water film forming part 19 (FIG. 2). ). As shown in FIG. 3, the water film forming unit 19 includes a main wet air blowing device 21 and a pair of sub wet air blowing devices 22 and 22. The main wet air blowing device 21 is arranged in parallel with the axis of the casting drum 4 and has a length longer than that of the resin supply device 5 (FIG. 4). The main wet air blowing device 21 is formed in a U-shaped cross section and has a main body 24 made of an aluminum material into which a sheathed heater 23 is cast. The main body 24 has a chamber 25 facing the casting drum 4, and the chamber 25 extends along the axis of the casting drum 4. The width D of the chamber 25 in the direction orthogonal to the axial direction of the casting drum 4 is preferably 20 to 300 mm, more preferably 50 to 100 mm. In this embodiment, the width D is set to 75 mm with respect to the casting drum 4 having a diameter of 1 m.

  A pipe 26 for ejecting humid air into the chamber 25 is disposed in the upper portion of the chamber 25. The lower half of the pipe 26 protrudes into the chamber 25, and small holes 26a for ejecting wet air are provided in a staggered pattern with a predetermined pitch. Further, a flexible tube (not shown) from the humid air generator 80 is connected to one end of the pipe 26. A stainless steel wire mesh member 29 is disposed in the opening of the chamber 25. This wire mesh member has a wire diameter of 0.12 mm, a mesh of 80 mesh, and an aperture ratio of 39.3%. In addition, as for the metal-mesh member 29, a mesh is 30 mesh or more, and opening ratio is 30 to 50%. Further, the metal mesh member 29 can also be constituted by a resin mesh member or the like.

  An edge member 28 made of an aluminum material is attached to an end of the main body 24 on the casting drum 4 side. The edge member 28 extends in parallel with the axis of the casting drum 4, and the end surface on the casting drum 4 side is inclined corresponding to the surface shape of the casting drum 4. Further, a heat insulating material 27 such as glass fiber is disposed on the upper part and both side parts of the main body 24.

  The pair of sub-humid air blowing devices 22 are disposed at both ends of the main humid air blowing device 21 on the side of the resin supply device 5 of the main wet air blowing device 21 (see FIG. 4). As shown in FIG. 3, each sub-humid air blowing device 22 has substantially the same structure as the main wet air blowing device 21, and is opposite to the main body 31 having the chamber 30, the upper portion of the main body 31, and the main wet air blowing device 21. A heat insulating material 32 provided on the side of the side, an edge member 33 provided on the casting drum 4 side of the main body 31, a stainless steel wire mesh 34 provided in the opening of the chamber 30, and a humid air generator 80. A pipe 35 for jetting wet air to which a flexible tube (not shown) is connected. A sheathed heater 36 is embedded in the main body 31.

  As shown in FIG. 5, the water film removing unit 20 includes a nonwoven fabric roll 37, a bearing unit 38 that rotatably supports the nonwoven fabric roll 37, and an air cylinder 39 for pressing the nonwoven fabric roll 37 against the surface of the casting drum 4. Have. The nonwoven fabric roll 37 extends in parallel with the axis of the casting drum 4 (see FIG. 4). The nonwoven fabric roll 37 is covered with a cover (not shown) and connected to a flexible tube extending from the vacuum pump 67a (FIG. 1).

  As shown in FIG. 6, cradles 41 are fixed to both ends of the water film forming apparatus 7 in the longitudinal direction. A flange portion 42 is provided on the side of the receiving drum 41 on the casting drum 4 side. In addition, a pair of brackets 43, 43 protrude in parallel from the water film forming device 7 toward the retracting device 9. Each bracket 43 is provided with a pin hole 43a.

  The evacuation device 9 is mainly composed of a moving unit 9a and a docking device 60 (see FIG. 1; the docking device is not shown). Details of the moving unit 9a will be described with reference to FIGS. The moving unit 9 a includes a moving block 44 and a moving frame 45 fixed to the upper portion of the moving block 44. The moving block 44 is disposed between a pair of brackets 43, 43 protruding from the water film forming apparatus 7. A pair of pins 54, 54 protruding from both ends of the moving block 44 are fitted into the corresponding pin holes 43 a, 43 a of the bracket 43, whereby the moving block 44 supports the water film forming device 7. Yes. The pins 54 and 54 are configured to be able to enter and leave the moving block 44 by a cylinder (not shown) provided in the moving block 44.

  Two sets of moving rollers 46 are rotatably provided on the side end surface of the moving frame 45. The moving roller 46 is disposed on a horizontal guide rail 48 supported by a support frame 47 as shown in FIG. Further, a moving air cylinder 49 is fixed to the support frame 47, and the moving frame 45 is supported by the rod tip 49a. In the moving unit 9 a, the moving frame 45 can reciprocate along the guide rail 48 by the moving air cylinder 49.

  The docking device 60 is disposed at both ends of the casting drum 4 and is attached to a fixed frame (not shown) for rotatably supporting the casting drum. As shown in FIG. 7, the docking device 60 mainly includes a contact portion 63 and an air cylinder 62 for raising and lowering the contact portion 63. The abutting portion 63 is formed in a shape with which the flange portion 42 of the water film forming apparatus 7 can abut.

  Holding links 70 are rotatably attached to both ends of the contact portion 63. A clamp roller 71 is rotatably mounted at the tip of each holding link 70, and a holding air cylinder 72 is connected to the other end. With such a docking device 60, the water film forming device 7 can take a retracted position indicated by a one-dot chain line in FIG. 1 and a water film forming position close to the casting drum 4. Here, the cylinder stroke of the elevating air cylinder 62 is set so that the lower end of each of the wet air blowing devices 21 and 22 is 50 mm or more from the surface of the casting drum 4 when the water film forming device 7 is moved to the retracted position. 3 and is set so that the gap E between the tips of the edge members 28 and 33 shown in FIG. 3 and the surface of the casting drum 4 is 1 to 5 mm, preferably 1 to 3 mm, when moved to the water film formation position. ing. When the gap E exceeds 5 mm, in the water film forming operation (described later) on the casting drum 4, the wet air is prevented from reaching the casting drum 4 by the accompanying airflow of the drum 4, and a good water film forming operation is performed. I can't. The retracted position is desirably 100 mm from the surface of the casting drum 4. In addition, it is desirable to set the water film formation position to 2 mm in order to form a uniform water film. The air flow rate of the air cylinder 62 is adjusted so that the speed at which the water film forming apparatus 7 is moved between the retracted position and the water film forming position can be set to 0.1 m / s or more. This moving speed is preferably 0.2 m / s.

  Each wet air generator 80 has a sealed container 81 as shown in FIG. As shown in FIG. 8, one end of a water supply pipe 82 for supplying water into the sealed container 81 is disposed in the sealed container 81. The water supply pipe 82 has a temperature raising tank 83 and an electromagnetic valve 84. The temperature raising tank 83 has a heater 85 for warming the internal water. Further, a temperature sensor (not shown) is attached to the temperature rising tank 83.

  An air supply pipe 86 is disposed at the bottom of the sealed container 81. The air supply pipe 86 has a control valve 87, and compressed air having a constant pressure can be supplied from a compressed air supply device (not shown) such as a compressor. The air supply pipe 86 has a large number of small holes (not shown) for ejecting compressed air in the sealed container 81. The small holes are set to have a diameter of 5 mm or less (preferably 3 mm or less). Further, the sealed container 81 has a heater 88 for warming water, a temperature sensor 89 for measuring the water temperature, and a liquid level sensor 90 for detecting the liquid level. The liquid level sensor 90 is disposed at a height of 300 mm or more from the bottom surface of the sealed container 81. The upper limit of the height of the liquid level sensor 90 is not particularly limited, but is normally regulated by the height of the hermetic container 81 that is limited in relation to other devices.

  A wet air supply pipe 91 is attached to the upper part of the sealed container 81. The humid air supply pipe 91 is mainly composed of a supply pipe main body 92 and a heater 93 for heat insulation. One end of the supply pipe main body 92 is attached to the upper end of the sealed container 81, and opens in the sealed container 81. The supply pipe main body 92 extends upward from the sealed container 81 and is bent so as to have an ascending slope in the middle. And the other end is connected with the other end of the flexible tube for supplying humid air to a humid air blowing apparatus. The heater 93 is disposed so as to cover the outer periphery of the supply pipe main body 92 and can be controlled by a temperature sensor (not shown).

  The film feeding device 8 is mainly composed of a suction roll 10 and a pair of guide rolls 11 and 12. The suction roll 10 is disposed in the vicinity of the casting drum 4 and extends parallel to the axis of the casting drum 4. Further, the suction roll 10 can be rotated clockwise by a driving device (not shown). The suction roll 10 has a large number of suction holes on the roll surface and is connected to a vacuum pump 13. The pair of guide rolls 11 and 12 are arranged on the downstream side of the suction roll 10 and are arranged in parallel with the suction roll 10.

  The film stretching unit 2 is disposed on the downstream side of the film manufacturing unit 1 and has a vertical axis stretching unit 14 and a horizontal axis stretching unit 15 in this order. The vertical axis stretching unit 14 is composed of a large number of rolls arranged in parallel, and can apply the tension in the transport direction to the resin film F from the film manufacturing unit 1 to stretch the resin film F in the vertical axis direction. . The horizontal-axis extending | stretching part 15 can hold | grip the both edges of the resin film F, and can perform the extending | stretching process of the width direction.

  The winding unit 3 has a winding roll 16. A pair of guide rolls 17 and 18 for guiding the resin film F from the film stretching section 2 to the winding roll 16 is disposed between the winding roll 16 and the film stretching section 2. Next, the manufacturing method of the biaxially stretched resin film by the said resin film manufacturing apparatus is demonstrated.

  In the film manufacturing unit 1, cooling water is supplied to the casting drum 4, and the surface temperature of the drum is set to 25 ° C., for example. Then, the casting drum 4 is rotated counterclockwise by a driving device (not shown). On the rotating casting drum 4, the sheet-like molten resin 5 a is pushed out from the die of the resin supply device 5. When the molten resin 5 a from the die comes into contact with the surface of the casting drum 4, it is cooled and solidified to form a resin film F. The resin film F is brought into close contact with the surface of the casting drum 4 by the static electricity applying device 6. Here, when a high voltage is applied to the static electricity applying wire 6a, the air in the vicinity of the static electricity applying device 6 is ionized, so that the surface of the casting drum 4 is charged and the resin film F is in close contact.

  The resin film F obtained by the casting drum 4 moves according to the rotation of the casting drum 4, leaves the casting drum 4, and is conveyed to the film feeding device 8. In the film feeding device 8, the resin film F from the casting drum 4 is in close contact with the surface of the suction roll 10, and is sent to the guide roll 11 by driving the suction roll 10. The resin film F is guided by the guide rolls 11 and 12 and conveyed to the film stretching unit 2. Here, the resin film F is stretched in the vertical axis direction and the horizontal axis direction in the vertical axis extending part 14 and the horizontal axis extending part 15, respectively, to become a biaxially stretched resin film. The biaxially stretched resin film is conveyed to the winding unit 3, guided by the guide rolls 17 and 18, and wound on the winding roll 16.

  In the manufacturing process described above, when the front end of the resin film F passes through the longitudinal axis extending portion 14, a water film starts to be formed on the surface of the casting drum 4. Next, the operation of forming this water film will be described. First, the moving air cylinder 49 of the retracting device 9 is operated to move the moving block 44 from the position indicated by the solid line in FIG. At this position, the tips of the edge members 28 and 33 of the wet air blowing devices 21 and 22 of the water film forming device 7 supported by the moving block 44 are separated from the surface of the casting drum 4 by about 100 mm.

  In this state, when the air cylinder 62 for raising and lowering the docking devices 60 and 60 disposed at both ends of the casting drum 4 is operated to project the rod, the contact portion 63 of the docking device 60 becomes the water film forming device. It moves in 7 directions and comes into contact with the flange portion 42 of the cradle 41 of the water film forming apparatus 7. Here, the air cylinder 72 for holding the docking device 60 is operated, and the rod projects. As a result, the holding links 70, 70 at both ends of the abutting portion 63 rotate, and the flange portion 42 of the water film forming apparatus 7 is pressed against the abutting portion 63 at the clamping roller 71 portion at the tip thereof. Connect firmly.

  As described above, when the docking operation between the docking device 60 and the water film forming device 7 is completed, the humid air is generated from the humid air generating device 80 corresponding to the main wet air blowing device 21 and the sub wet air blowing devices 22 and 22 next. Begin to supply. Here, the humid air supply operation by the humid air generator 80 will be described first. In the water supply pipe 82 of the humid air generator 80, water is first stored in the temperature rising tank 83. The water stored in the temperature raising tank 83 is heated by the heater 85. The water in the temperature raising tank 83 thus heated is continuously supplied into the sealed container 81 through the water supply pipe 82 when the electromagnetic valve 84 is opened. Thereby, in the sealed container 81, the water from the water supply pipe 82 is stored up to the level of the liquid level sensor 90. When the water level in the sealed container 81 reaches the level of the liquid level sensor 90, the control valve 84 is closed in accordance with a signal from the liquid level sensor 90, and the supply of water into the sealed container 81 is stopped. In addition, although the water supplied in the airtight container 81 may be normal drinking water, ion-exchange water is preferable. This is because a small hole (not shown) of the air supply pipe 86 is likely to be clogged due to calcium contained in the drinking water.

The water from the water supply pipe 82 stored in the hermetic container 81 is heated by the heater 88 so as to reach a constant temperature in the range of 81 to 90 ° C. Here, the heater 88 operates according to a signal from the temperature sensor 89, and maintains the water temperature in the sealed container constant. When the hot water in the sealed container 81 is set to a constant temperature, the compressed air having a constant pressure starts to be supplied from a compressed air supply device (not shown) into the air supply pipe 86. In addition, it is preferable to set the supply amount of compressed air to 7-30 liters / minute in the range of 1-5 kgf / cm < ² > of gauge pressures. When the control valve 87 is opened, the compressed air is jetted into warm water from a small hole (not shown). The jetted air rises in the hot water and absorbs moisture, becomes humid air, and is stored in the upper part of the sealed container 81. Here, since the hole diameter of the small hole of the air supply pipe 86 is set in the above-described range as described above, the air from the air supply pipe 86 becomes a fine bubble and rises in the warm water. Moreover, since the depth of the warm water is set in the above range, a sufficient residence time of the air in the warm water is ensured. Furthermore, since the water temperature is set in the above-mentioned temperature range, the air in the warm water efficiently absorbs moisture. For this reason, the air from the air supply pipe 86 is stored in the upper portion of the sealed container 81 as stable, stable humid air.

  The humid air stored in the upper part of the sealed container 81 is supplied to the corresponding humid air blowing device through the humid air supply pipe 91. Here, the humid air rises in the supply pipe main body 92 and is supplied to the humid air blowing device via the flexible tube. The humid air in the supply pipe main body 92 is kept warm by the heater 93. For this reason, the humid air is prevented from condensing in the supply pipe main body 92. Even if the supply pipe main body 92 condenses, the condensed water returns to the sealed container 81 because the supply pipe main body 92 has an upward slope. As a result, moist air with a constant water content can be stably supplied to the water film forming apparatus 7.

  When the hot water in the sealed container 81 decreases and the liquid level decreases, the liquid level sensor 90 operates to open the electromagnetic valve 84 and water is supplied from the water supply pipe 82. The water to be replenished here is preheated in the temperature rising tank 83 to the temperature of the hot water stored in the sealed container 81. If it carries out like this, even if new warm water is supplied in the airtight container 81, the temperature of the warm water in the airtight container 81 does not change easily. As a result, the humid air generator 80 can continue to stably supply the humid air having a constant humidity.

  The humid air supplied to the water film forming device 7 is supplied into the pipes 26 and 35 of the main wet air blowing device 21 and the sub wet air blowing devices 22 and 22, and is discharged into the respective chambers 25 and 30. Here, the main bodies 24 and 31 of the wet air blowing devices 21 and 22 are preheated by the sheathed heaters 23 and 36, respectively. In this way, the humid air is discharged into the chambers 25 and 30 without condensation in the pipes 26 and 35. The wet air discharged from the pipes 26 and 35 can be uniformly diffused into the chambers 25 and 30 because the wire mesh members 29 and 34 are disposed at the outlet portions of the chambers 25 and 30. In addition, since the water film forming apparatus 7 is sufficiently separated from the surface of the casting drum 4 as described above, the humid air from each of the wet air blowing apparatuses 21 and 22 hardly reaches the surface of the casting drum 4. For this reason, on the surface of the casting drum 4, condensation due to the humid air leaking from the humid air blowing devices 21, 22 hardly occurs.

  Next, when the humid air is sufficiently diffused in the chambers 25 and 30 of the main wet air blowing device 21 and the sub wet air blowing devices 22 and 22, the water film forming device 7 is shown as a solid line from the position indicated by the one-dot chain line in FIG. Move to the position indicated by. Here, in the moving block 44, the pin 54 is moved into the moving block 44 by a cylinder for pin operation (not shown) and extracted from the pin hole 43 a of the bracket 43. Thereby, the support of the water film forming apparatus 7 by the moving block 44 is released. Next, when the lifting / lowering air cylinder 62 of each docking device 60 is actuated to retract its rod, the water film forming device 7 moves away from the moving block 44, and the water film forming position close to the surface of the casting drum 4 is reached. Move to. At this time, the air supply amount of the lifting air cylinder 62 is set so that the moving speed of the water film forming device 7 is 0.2 m / s. It approaches the surface of the casting drum 4. At this water film forming position, the gap E (FIG. 3) between the lower ends of the edge members 28 and 33 of the wet air blowing devices 21 and 22 and the surface of the casting drum 4 is 2 mm.

  In this state, the humid air supplied onto the casting drum 4 from the chambers 25 and 30 of the humid air blowing devices 21 and 22 through the stainless steel wire mesh 29 and 34 is cooled by touching the casting drum 4 and condensed to form water. A film is formed. At this time, since the gap between the lower ends of the wet air blowing devices 21 and 22 and the surface of the casting drum 4 is set to about 2 mm, a uniform water film is formed on the surface of the casting drum 4. Further, when the wet air blowing devices 21 and 22 are brought close to the surface of the casting drum 4, the air cylinder 62 makes the wet air blowing devices 21 and 22 approach at a high speed at a moving speed of 0.2 m / s. The boundary between the part where the film is not formed and the part where the film is formed can be clarified, and the thickness unevenness of the water film can be suppressed.

  Further, a water film is continuously formed on the surface of the casting drum 4, but the width of the opening of the chamber 25 of the main wet air blowing device 21 is not less than the film length in the axial direction and 75 mm in the direction intersecting with the film length. Therefore, the humid air is in contact with the rotating casting drum 4 for a sufficient time, and a more uniform water film can be formed. In addition, water films formed by the sub-wet air blowing device 22 are formed on both ends of the water film formed by the main wet air blowing device 21. For this reason, since the water film on the casting drum 4 is prevented from drying at both ends, the thickness at the center and both ends becomes uniform.

  The water film disposed on the surface of the casting drum 4 eliminates air flowing into the contact portion with the casting drum 4 along with the molten resin 5a from the base. As a result, since the adhesion between the resin film F and the casting drum 4 is further improved, the resin film F can be produced at a higher speed on the casting drum 4. In the casting drum 4 after the resin film F has been peeled off, the water film disposed between the casting drum 4 and the resin film F remains as water droplets. The water droplets move to the water film forming device 7 according to the rotation of the casting drum 4 and are removed by the nonwoven fabric roll 37 in the water film forming device 7. Here, the nonwoven fabric roll 37 is pressed against the surface of the casting drum 4 by the air cylinder 39 and rotates to absorb the water film on the surface of the casting drum 4. The water absorbed by the nonwoven fabric roll 37 is sucked and removed by the vacuum pump 67a.

  A water film is formed again on the surface of the casting drum 4 from which water droplets have been removed by the nonwoven fabric roll 37 by the wet air blowing devices 21 and 22. At this time, since the water film is removed by the nonwoven fabric roll 37 as described above, a uniform water film with little thickness unevenness can be formed. For this reason, in the film manufacturing part 1, since the adhesiveness of the resin film F and the casting drum 4 can be maintained favorable, film breakage due to uneven peeling of the resin film F hardly occurs, and the resin film F can be continuously produced at high speed.

  The thickness of the water film obtained by the water film forming apparatus in the present invention is preferably 0.2 to 0.6 [mu] m, more preferably 0.2 to 0.3 [mu] m. If the water film is too thin, the peeling performance when the film is separated from the drum is deteriorated and film breakage is induced. If the water film is too thick, the film slips on the drum surface, leading to poor film thickness or film breakage.

  In order to obtain a water film thickness of 0.3 μm on the casting drum 4 having a surface temperature of 35 ° C. in the water film forming apparatus 7 having a width of 0.85 m, conventionally, the supply amount of the humid air to the pipe 26 is 10 liters / minute. Need to be reduced. However, it is difficult to keep the water film thickness variation in the width direction of the casting drum 4 within 20%.

  Therefore, the supply amount of the humid air to the pipe 26 is nearly doubled by providing the opening 50 and the adjustment valve 51 capable of adjusting the opening ratio at the other end of the pipe 26 other than the humid air supply section. A sufficient pressure is ensured inside, and the amount of discharge is reduced by adjusting the control valve 51 from the opening 50 provided at the other end of the pipe 26 except for the amount of humid air necessary for ejection from the humid air generator 21. By pulling out at 18 liters / minute, a uniform water film can be formed on the surface of the casting drum 4, and the water film thickness unevenness in the width direction of the casting drum 4 is kept within 20%. Can do. At this time, the inner diameter of the pipe 26 for ensuring a sufficient pressure inside the pipe 26 is preferably in a range of 15 mm to 50 mm. More preferably, it is the range of 20-35 mm. When the inner diameter of the pipe 26 is less than 15 mm, the flow velocity of the humid air inside the pipe 26 is increased, resulting in a water film thickness spot. Further, when the inner diameter of the pipe 26 is larger than 50 mm, sufficient pressure cannot be secured inside the pipe 26 and the water film thickness unevenness is also caused.

  The thickness of the water film formed on the surface of the casting drum 4 is measured with a water film measuring device.

  A polarization infrared moisture meter (manufactured by Kurashiki Boseki Co., Ltd.) is incorporated in the measuring section of the water film measuring apparatus. This water film measuring device is arranged in a section from when the molten resin 5a is cast on the casting drum 4 until it is separated, and moves in the width direction of the resin film 5a to measure the water film thickness. The thickness of the water film is adjusted while observing the maximum value and the minimum value for each arbitrary section in the width direction of the resin film 5a and the average value for each arbitrary section in the width direction.

  The present invention relates to a water film forming apparatus, and more particularly to a water film forming apparatus used in a resin film manufacturing apparatus for manufacturing a resin film by supplying a sheet-like molten resin onto a rotating drum.

The schematic front view of the resin film manufacturing apparatus by which one Example of this invention was employ | adopted. The front view of the evacuation apparatus part of the said resin film manufacturing apparatus. The longitudinal cross-sectional schematic of the water film formation part of the said Example. The plane schematic of the casting drum part of the said resin film manufacturing apparatus. The schematic of the water film removal part of the said Example. The perspective fragmentary view of the connection part of the said evacuation apparatus and the said water film formation part. Schematic of the docking device part of the said evacuation device. The schematic block diagram of the humid air generator part of the said Example.

Explanation of symbols

4 Casting drum 5 Resin supply device 20 Water film removal unit 21. Main wet air blowing device 22 Sub wet air blowing device 25, 30 Chamber 26, 35 Pipe 29, 34 Wire mesh member 50 Opening 51 Control valve

Claims (6)

A water film forming apparatus for supplying a sheet-like molten resin onto a rotating casting drum and forming a water film on the surface of the casting drum in a resin film manufacturing apparatus for manufacturing a resin film,
An apparatus main body that has a chamber that is arranged close to the casting drum surface and opens on the casting drum surface side;
Wet air jetting means for jetting wet air to the chamber of the apparatus body;
The water film formation apparatus of the resin film manufacturing apparatus provided with the opening part and control valve which were arrange | positioned in order to make the casting drum surface jet out humid air uniformly.   A pipe is used as the humid air ejecting means, the inner diameter of the pipe is 15 mm or more, and the supply of the humid air to the pipe is 7 to 30 liters / minute, which is different from the humid air supply part of the pipe. The water film forming apparatus of the resin film manufacturing apparatus according to claim 1, wherein the discharge amount is adjusted to 3 to 18 liters / minute by an adjustment valve of an opening provided at the other end of the resin film. A water film forming section for disposing a water film on the casting drum;
The thickness measurement part for measuring the thickness of the said water film arrange | positioned at the said casting drum is provided, The said water film formation part can adjust water film thickness continuously by this measurement part. The water film forming apparatus of the resin film manufacturing apparatus described in 1.   The water film formation apparatus of the resin film manufacturing apparatus in any one of Claims 1-3 whose water film thickness unevenness of the width direction formed in the said casting drum is less than 20%.   The water film formation apparatus of the resin film manufacturing apparatus in any one of Claims 1-4 which sets the water film thickness formed in the said casting drum to 0.2-0.6 micrometer.   The film manufacturing method using the water film forming apparatus in any one of Claims 1-5.

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