JP2019166795A - Film-forming apparatus - Google Patents

Abstract

To provide a film-forming apparatus capable of elevating uniformity of film thickness.SOLUTION: The film-forming apparatus is assembled with a die for extruding a molten resin from a cyclic discharge port 18a to a tubular form and a film thickness adjustment part 2 for adjusting a film thickness of the molten resin extruded from the discharge port 18a. The die includes a lip part defining a circumference of the discharge port. The film thickness adjustment part 2 has plural adjustment units 16 arranged so as to surround the lip part, wherein each of the plural adjustment units 16 controls the width of the discharge port 18a in its radial direction by elastic deformation of the lip part, and uniforming means for making the temperature of the lip part uniform.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a film forming apparatus.

  2. Description of the Related Art A film forming apparatus is known that forms a film by solidifying molten resin extruded in a tube shape from an annular discharge port of a die with cooling air from an air ring. 2. Description of the Related Art Conventionally, a film forming apparatus has been proposed in which the outer peripheral member of a die that defines the outer periphery of an annular discharge port is elastically deformed by pressing it with a bolt (Patent Document 1). ).

JP-A-3-216324

  Since the conventional film forming apparatus described above can partially control the film thickness in the circumferential direction, the uniformity of the film thickness can be improved. However, the demand for higher uniformity does not cease.

  This invention is made | formed in view of such a condition, The objective is to provide the film forming apparatus which can improve the uniformity of film thickness more.

  In order to solve the above problems, a film forming apparatus according to an aspect of the present invention includes a die for extruding a molten resin in a tube shape from an annular discharge port, and a film for adjusting the film thickness of the molten resin extruded from the discharge port A thickness adjusting unit. The die includes a lip portion that defines the outer periphery of the discharge port. The film thickness adjustment unit is a plurality of adjustment units arranged so as to surround the lip part, each of which includes a plurality of adjustment units that elastically deform the lip part to adjust the radial width of the discharge port, and the lip Homogenizing means for homogenizing the temperature of the part.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  According to the present invention, the uniformity of the film thickness can be further improved.

It is a figure which shows schematic structure of the film forming apparatus which concerns on embodiment. It is sectional drawing which shows the die | dye of FIG. 1, and a film thickness adjustment part. It is a top view of the die | dye of FIG. 1, and a film thickness adjustment part. It is a perspective view which shows the upper part of the outer peripheral member of FIG. 2, and the adjustment unit attached to it. It is a side view which shows the upper part of the outer peripheral member of FIG. 2, and the adjustment unit attached to it. FIG. 3 is a perspective view showing the adjustment unit of FIG. 2. FIG. 3 is a perspective view showing the adjustment unit of FIG. 2. 8A and 8B are explanatory diagrams for explaining the operation of the adjustment unit. FIG. 3 is a cross-sectional view showing the adjustment unit of FIG. 2 and its periphery. It is a block diagram which shows typically the function and structure of a control apparatus of FIG. It is an AA line end view of FIG. It is sectional drawing which shows the thermal radiation member which concerns on a modification, and its periphery. FIGS. 13A and 13B are end views showing a heat dissipating member according to another modification and the periphery thereof.

  Hereinafter, the same or equivalent components and members shown in the respective drawings are denoted by the same reference numerals, and repeated descriptions thereof are omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  FIG. 1 shows a schematic configuration of a film forming apparatus 1 according to the embodiment. The film forming apparatus 1 forms a tubular film. The film forming apparatus 1 includes a die 10, a film thickness adjusting unit 2, a pair of stabilizing plates 4, a pair of pinch rolls 5, a thickness measuring sensor 6, and a control device 7.

  The die 10 shapes the molten resin supplied from an extruder (not shown) into a tube shape. In particular, the die 10 forms the molten resin into a tube shape by extruding the molten resin from a ring-shaped slit 18 (described later in FIG. 2).

  The film thickness adjusting unit 2 adjusts the film thickness and cools the molten resin extruded from the die 10. When the molten resin is cooled, a film is formed.

  The pair of stabilizing plates 4 is disposed above the film thickness adjusting unit 2 and guides the formed film between the pair of pinch rolls 5. The pinch roll 5 is disposed above the stabilizer 4 and is folded flat while pulling up the guided film. The folded film is wound up by a winder (not shown).

  The thickness measuring sensor 6 is disposed between the film thickness adjusting unit 2 and the stabilizing plate 4. The thickness measurement sensor 6 measures the film thickness at each position in the circumferential direction around the tube-shaped film at a predetermined cycle. The measurement value by the thickness measurement sensor 6 is sent to the control device 7.

  The control device 7 sends a control command corresponding to the measurement result received from the thickness measurement sensor 6 to the film thickness adjusting unit 2. In response to this control command, the film thickness adjusting unit 2 adjusts the width of the slit 18 (particularly, its discharge port) so that the variation in film thickness is reduced.

  FIG. 2 is a cross-sectional view showing the die 10 and the film thickness adjusting unit 2. FIG. 3 is a top view of the die 10 and the film thickness adjusting unit 2. In FIG. 3, the cooling device 3, the support member 58, and the closing member 66 are not shown.

  The die 10 includes a die main body 11, an inner peripheral member 12, and an outer peripheral member 14. The inner peripheral member 12 is a substantially columnar member placed on the upper surface of the die body 11. The outer peripheral member 14 is an annular member and surrounds the inner peripheral member 12. Between the inner peripheral member 12 and the outer peripheral member 14, a slit 18 extending in a vertical direction in a ring shape is formed. The molten resin flows upward through the slit 18, and the molten resin is pushed out from the discharge port (that is, the upper end opening) 18a of the slit 18 to form a film having a thickness corresponding to the width of the discharge port 18a.

  A plurality of heaters 56 are mounted on the outer periphery of the die body 11. In addition, heaters 56 are mounted on the outer periphery of the lower portion of the outer peripheral member 14 (specifically, a large diameter portion 27 described later) and the outer periphery of the upper portion of the outer peripheral member 14 (specifically, a small diameter portion 25 described later). The die body 11 and the outer peripheral member 14 are heated to a required temperature by the heater 56. Thereby, the molten resin flowing inside the die 10 can be maintained at an appropriate temperature and in a molten state.

  The film thickness adjusting unit 2 includes the cooling device 3, a plurality of (here, 32) adjustment units 16, a support member 58, a closing member 66, and a plurality (the same number as the adjustment unit 16, 32 here) of heat dissipation. Member 68.

  The cooling device 3 is disposed above the die 10. The cooling device 3 includes an air ring 8 and an annular rectifying member 9. The air ring 8 is a ring-shaped housing whose inner peripheral portion is recessed downward. A ring-shaped air outlet 8 a that opens upward is formed on the inner peripheral portion of the air ring 8. The air outlet 8a is formed to be concentric with the ring-shaped slit 18 in particular.

  A plurality of hose ports 8 b are formed at equal intervals in the circumferential direction on the outer peripheral portion of the air ring 8. A hose (not shown) is connected to each of the plurality of hose ports 8b, and cooling air is sent into the air ring 8 from the blower (not shown) via this hose. The cooling air sent into the air ring 8 is blown from the blowout port 8a and blown to the molten resin.

  The flow regulating member 9 is disposed in the air ring 8 so as to surround the air outlet 8a. The rectifying member 9 rectifies the cooling air sent into the air ring 8. Thereby, cooling air blows off from the blower outlet 8a with the uniform flow volume and wind speed in the circumferential direction.

  The plurality of adjustment units 16 are arranged, for example, at equal intervals in the circumferential direction so as to surround the upper end side of the outer circumferential member 14. In particular, the adjustment unit 16 is attached to the outer peripheral member 14 in a cantilevered manner. Each of the plurality of adjustment units 16 is configured to apply a radially inward pressing load or a radially outward tensile load to the outer peripheral member 14. Therefore, by adjusting the plurality of adjusting units 16, the width of the discharge port 18a can be partially adjusted in the circumferential direction, and the film thickness can be partially controlled in the circumferential direction. When the film thickness varies in the circumferential direction, for example, a tensile load is applied to the outer peripheral member 14 from the adjustment unit 16 corresponding to a thin portion (for example, located below the thin portion), The gap of the discharge port 18a below the thin portion is increased. Thereby, the dispersion | variation in film thickness becomes small.

  The support member 58 is an annular member, and is placed and fixed on the plurality of adjustment units 16 so as to surround the upper part of the outer peripheral member 14. The cooling device 3 is fixed above the support member 58. That is, the support member 58 supports the cooling device 3.

  The closing member 66 is a thin disk-like member having a hole formed in the center, and is provided between the inner peripheral portion of the air ring 8 and the plurality of adjusting units 16. A detailed functional configuration of the closing member 66 will be described later with reference to FIG.

  The plurality of heat radiating members 68 are disposed so as to surround the outer peripheral member 14 (specifically, a flexible lip portion 22 described later), and function as a uniformizing means for making the temperature of the flexible lip portion 22 more uniform in the circumferential direction. To do. The detailed functional configuration of the heat dissipation member 68 will be described later with reference to FIG.

  4 and 5 are a perspective view and a side view showing the upper part of the outer peripheral member 14 and the adjustment unit 16 attached thereto. 4 and 5, only one adjustment unit 16 is shown, and the display of the remaining adjustment units 16 is omitted. 6 and 7 are perspective views showing the adjustment unit 16. FIG. 7 shows a state where one of the pair of support members 30 is removed.

  The upper part of the outer peripheral member 14 includes a small diameter portion 25 formed at the upper end, a medium diameter portion 26 formed below the small diameter portion 25 with a larger diameter than the small diameter portion 25, and a medium diameter portion below the medium diameter portion 26. And a large-diameter portion 27 having a larger diameter than 26. The small diameter portion 25 has a flexible lip portion 22. The flexible lip portion 22 refers to a portion of the small-diameter portion 25 above the concave notch portion 20 provided along the circumferential direction. The flexible lip part 22 is elastically deformed with the notch part 20 as a boundary. The flexible lip portion 22 includes a cylindrical main body portion 28 and an annular protruding surrounding portion 29 that protrudes radially outward from the main body portion 28.

  The adjustment unit 16 includes a pair of support members 30 attached to the outer peripheral member 14, a rotation shaft 32 fixed to the pair of support members 30, and a lever 34 supported rotatably about the rotation shaft 32 as a fulcrum. The operating rod 36 that operates in the axial direction upon receiving the rotational force of the lever 34, the connecting member 38 that connects the operating rod 36 and the flexible lip portion 22 in the axial direction, and the operating rod that is slidable in the axial direction are supported. A bearing member 40 that performs rotation, and an actuator 24 that applies a rotational force to the lever 34.

  The pair of support members 30 are formed in a flat plate shape and screwed to the outer peripheral member 14 so as to be parallel to each other. A space for interposing the lever 34 is provided between the pair of support members 30. The bearing member 40 is formed in a rectangular shape and is screwed to the outer peripheral member 14 on the radially inner side of the support member 30. The bearing member 40 is formed with an insertion hole 42 penetrating in the radial direction. The inner peripheral surface of the insertion hole 42 constitutes a so-called sliding bearing (oil-free type bearing), and supports the operating rod 36 so as to be slidable.

  The rotation shaft 32 is fixed to the pair of support members 30 so that the shaft faces the horizontal direction and is substantially orthogonal to the radial direction.

  The operating rod 36 is formed in a stepped cylindrical shape, and an intermediate portion thereof is inserted into the insertion hole 42 of the bearing member 40. A reduced diameter portion 44 is provided on the outer side in the axial direction of the operating rod 36. The reduced diameter portion 44 functions as a connecting portion with the lever 34 as will be described later. A concave engaging portion 46 is provided on the axially inner side of the operating rod 36. The engaging portion 46 functions as a connecting portion with the connecting member 38 as will be described later. The outer peripheral surface (hereinafter referred to as “pressure receiving surface 23”) of the overhang surrounding portion 29 of the flexible lip portion 22 faces the distal end surface of the operating rod 36.

  The connecting member 38 is formed in a bifurcated shape in a longitudinal sectional view. Specifically, the connecting member 38 is provided with engaging portions 48 and 50 protruding downward on the surface facing the outer peripheral member 14 in the axial direction. The engaging portion 48 is generally complementary to the engaging portion 46 of the actuating rod 36. An annular engaging groove 52 that is recessed downward in the axial direction is formed in the overhang surrounding portion 29 of the flexible lip portion 22. The engaging portion 50 is substantially complementary to the engaging groove 52.

  The operating rod 36 and the connecting member 38 are screwed so that the engaging portion 48 is engaged with the engaging portion 46 and the engaging portion 50 is engaged with the engaging groove 52. The opposing surfaces of the engaging portion 48 and the engaging portion 46 are tapered surfaces. Thereby, as the screw 54 is fastened, the distal end surface of the operating rod 36 is pressed against the pressure receiving surface 23 of the flexible lip portion 22, and the operating rod 36 and the flexible lip portion 22 are firmly fixed. A part of the flexible lip portion 22 is sandwiched between the engaging portion 50 of the connecting member 38 and the distal end portion of the operating rod 36. Thereby, the action | operation rod 36 is connected with the flexible lip | rip part 22 in the axial direction.

  The lever 34 has a long plate-like main body 60 extending in the radial direction, and one end of the lever 34 is rotatably supported by the rotation shaft 32. The lever 34 is provided so that the main body 60 and the operating rod 36 are substantially parallel in the non-operating state. A bifurcated connecting portion 62 is provided so as to extend from one end portion of the main body 60 in a direction perpendicular to the axis of the main body 60. That is, the connecting portion 62 is composed of a pair of connecting pieces 64, and the interval between them is slightly larger than the outer diameter of the reduced diameter portion 44 of the actuating rod 36, and their width is slightly smaller than the length of the reduced diameter portion 44. Yes. With such a configuration, the lever 34 and the operating rod 36 are connected in such a manner that the connecting portion 62 fits into the reduced diameter portion 44.

  Note that the present embodiment is not limited to this embodiment as long as the rotational force of the lever 34 is directly applied to the operating rod 36. For example, the connecting portion 62 may not extend from the axis of the main body 60 in the direction perpendicular to the axis. The axis of the main body 60 and the extending direction of the connecting portion 62 may form an acute angle or an obtuse angle. Further, the main body 60 and the operating rod 36 may not be parallel when the lever 34 is in an inoperative state.

  The actuator 24 is pneumatically driven in the present embodiment, and includes two sets of bellows 70 and 72 and bellows 71 and 73 that are operated by supplying and discharging compressed air, a first base 75, and a shaft of the first base 75. A second base 76 disposed on the lower side in the direction and four connecting rods 77 are included. The first base 75 and the second base 76 are spaced apart in the axial direction and are connected by four connecting rods 77. Bellows 70 and 72 are disposed between the lever 34 and the first base 75, and bellows 71 and 73 are disposed between the lever 34 and the second base. That is, the end portion that is the power point of the lever 34 is supported so as to be sandwiched between the bellows 70 and 72 and the bellows 71 and 73. By supplying compressed air to one of the bellows 70, 72 or the bellows 71, 73, the lever 34 is driven to rotate clockwise or counterclockwise in the drawing.

  In FIG. 5, when pressure is applied to the bellows 70 and 72 by the supply of compressed air and the bellows 70 and 72 extend, the lever 34 rotates counterclockwise in the drawing, and the rotational force is the left side in the axial direction of the operating rod 36. (Ie, radially outward). As a result, a tensile load is applied to the flexible lip portion 22 and the corresponding gap (that is, the radially inner side of the adjustment unit 16) of the slit 18 changes in a direction in which the gap of the discharge port 18a increases. On the other hand, when pressure is applied to the bellows 71 and 73 by the supply of compressed air and the bellows 71 and 73 extend, the lever 34 rotates clockwise in the figure, and the rotational force is the right side in the axial direction of the operating rod 36 (ie, the diameter). Converted to force inward). As a result, a pressing load is applied to the flexible lip portion 22 and the corresponding gap of the slit 18 is changed in a decreasing direction.

  In order to realize such pneumatic driving, compressed air is supplied from a pressure adjusting device (not shown) via a supply path 75 a formed in the first base 75 and a supply path 76 a supplied to the second base 76. The The pressure adjusting device controls the pressure in the bellows 70 to 73 based on a control command from an adjusting operation control unit 83 (described later).

  FIG. 8 is an explanatory diagram for explaining the operation of the adjustment unit 16. FIG. 8A shows the neutral state of the adjustment unit 16 (the state in which the bellows 70 to 73 are both inactive), and FIG. 4B shows the expansion operation state of the adjustment unit 16 (only the bellows 70 and 72 are activated). Status).

  According to the adjusting unit 16, the rotational force of the lever 34 is directly applied to the operating rod 36 at the point of action P. That is, the rotational force of the lever 34 is applied to the flexible lip portion 22 as a force in the axial direction of the operating rod 36. At that time, since the operating rod 36 is stably supported by the outer peripheral member 14, the axial force is efficiently transmitted to the flexible lip portion 22. As a result, the driving force for adjusting the gap between the inner peripheral member 12 and the outer peripheral member 14 can be efficiently applied.

  In the present embodiment, as shown in FIG. 8A, a straight line connecting a connection point between the lever 34 and the actuating rod 36 (the action point P of the lever 34) and the rotating shaft 32 (a fulcrum of the lever 34). L1 is configured to be orthogonal to the axis L2 of the operating rod 36. Thereby, the tangential direction of the virtual circle C passing through the action point P with the rotation shaft 32 as the center coincides with the axial direction of the operating rod 36.

  For this reason, as shown in FIG. 8B, the direction of the operating point P of the rotational force of the lever 34 coincides with the axial direction of the operating rod 36. As a result, the rotational force of the lever 34 becomes the driving force in the axial direction of the actuating rod 36 as it is, and the force transmission efficiency can be maximized. That is, the driving force of the actuator 24 when the flexible lip portion 22 is expanded can be applied very efficiently (see the thick arrow in the figure).

  Although illustration is omitted, even when the adjustment unit 16 is in a narrow operation state (a state in which only the bellows 71 and 73 are operated), only the direction of the force in FIG. The direction at the point P coincides with the axial direction of the operating rod 36. As a result, the rotational force of the lever 34 becomes the driving force in the axial direction of the actuating rod 36 as in the expansion operation, and the force transmission efficiency can be maximized. That is, according to the adjustment unit 16, it is possible to efficiently apply the driving force for adjusting the interval between the discharge ports 18 a of the slit 18.

  Note that the present embodiment is not limited to this embodiment as long as the rotational force of the lever 34 is directly applied to the operating rod 36. For example, as a result of the extending direction of the connecting portion 62 (the direction connecting the rotation shaft 32 and the action point P) and the axial direction of the operating rod 36 forming an acute angle or an obtuse angle, the direction at the action point P of the rotational force of the lever 34 The configuration may be such that the axial direction of the actuating rod 36 (also referred to as “axial force acting direction” for convenience) does not match (for convenience, also referred to as “rotational force acting direction”). In that case, while the main body 60 and the operating rod 36 are parallel, the axis of the main body 60 and the extending direction of the connecting portion 62 may form an acute angle or an obtuse angle. Alternatively, the axis of the main body 60 and the extending direction of the connecting portion 62 may be perpendicular, while the main body 60 and the operating rod 36 may not be parallel. Alternatively, the axis of the main body 60 and the extending direction of the connecting portion 62 may form an acute angle or an obtuse angle, and the main body 60 and the actuation rod 36 may not be parallel. Moreover, you may employ | adopt as a main body 60 what has a bending part or a curved part in at least one part (structure which cannot necessarily specify an axis line).

  FIG. 9 is a cross-sectional view showing the adjustment unit 16 and its periphery. First, let us consider a case where there is no closing member 66. In this case, when the cooling air is blown upward from the air outlet 8a of the air ring 8, a space 90 below the air outlet 8a, that is, a space 90 surrounded by the air ring 8, the molten resin, and the plurality of adjusting units 16 is obtained. , Become negative pressure. As a result, air flows into the space 90 from below the air ring 8 through the annular gap 84 between the main body portion 28 of the flexible lip portion 22 of the outer peripheral member 14 and the inner peripheral portion of the air ring 8, and is blown to the molten resin. . Specifically, from below or / and the outer peripheral side of the adjustment unit 16, air passes through a plurality of (here, 32) gaps between the adjustment units 16 and enters the space 88 between the air ring 8 and the plurality of adjustment units 16. Flows into the space 90 from the space 88. Since the gap between the adjusting units 16 is discontinuous in the circumferential direction, the air volume of the air flowing into the space 88 varies in the circumferential direction, and therefore the air volume of the air flowing from the space 88 into the space 90 also varies in the circumferential direction. When wind with a non-uniform air volume in the circumferential direction is blown onto the molten resin, the timing at which the molten resin solidifies becomes non-uniform in the circumferential direction and the film thickness becomes non-uniform in the circumferential direction.

  On the other hand, in the present embodiment, a closing member 66 is provided between the inner peripheral portion of the air ring 8 and the adjustment unit 16. The closing member 66 is configured to close the gap 84. In other words, the closing member 66 is configured to close the flow path from between the outer peripheral member 14 and the plurality of adjustment units 16 and the air ring 8 to the upper side of the air ring 8 through the inner peripheral side of the air ring 8. The

  Specifically, an annular recess 94 that is recessed downward is formed on the outer edge of the upper end of the main body portion 28 of the flexible lip portion 22. The closing member 66 has an inner diameter larger than the inner diameter of the bottom surface 94a of the recess 94 (the outer diameter of the upper surface 28a of the main body 28) and smaller than the outer diameter of the bottom surface 94a. The closing member 66 is provided such that the inner peripheral end of the lower surface 66 a abuts (places) the bottom surface 94 a of the recess 94, and the outer peripheral end of the lower surface 66 a abuts (places) the support member 58. ing.

  The closing member 66 prevents air from flowing into the space 90. Although the closing member 66 contacts the flexible lip portion 22 but is not fixed to the flexible lip portion 22, the flexible lip portion 22 can be elastically deformed by receiving a load from the adjustment unit 16. That is, the closing member 66 does not hinder the elastic deformation of the flexible lip portion 22.

  FIG. 10 is a block diagram schematically showing the function and configuration of the control device 7. Each block shown here can be realized in hardware by an element such as a CPU of a computer or a mechanical device, and in software it is realized by a computer program or the like. Draw functional blocks. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

  The control device 7 includes a holding unit 80, an acquisition unit 81, a determination unit 82, and an adjustment operation control unit 83. The acquisition unit 81 acquires a measurement value obtained by the thickness measurement sensor 6. The holding unit 80 includes a film thickness and a load that the adjustment unit 16 should apply to the outer peripheral member 14 in order to set a film to be formed later to a target film thickness when the film thickness is measured by the thickness measurement sensor 6. Are stored in association with each other.

  The determining unit 82 determines the load that each adjusting unit 16 should apply to the outer circumferential member 14 in order to reduce the variation in film thickness. In particular, the determination unit 82 determines a load to be applied to the outer circumferential member 14 with reference to the measurement value by the thickness measurement sensor 6 and the holding unit 80. In addition, the determination unit 82 calculates how much the pressure of the bellows 70 to 73 of the adjustment unit 16 is controlled so that the determined load is applied to the outer peripheral member 14. The adjustment operation control unit 83 sends a control command to the pressure adjustment device so that the pressure of the bellows 70 to 73 becomes the pressure calculated by the determination unit 82.

  Operation | movement of the film forming apparatus 1 comprised as mentioned above is demonstrated. The molten resin is extruded from the discharge port 18a of the die 10, and the cooling device 3 blows cooling air to the extruded molten resin. Thereby, a film is shape | molded. At this time, the thickness measurement sensor 6 measures the film thickness at each position in the circumferential direction at a predetermined cycle. The control device 7 controls each adjustment unit 16 of the film thickness adjustment unit 2 based on the measurement value by the thickness measurement sensor 6 so that the variation in the film thickness is reduced.

  The above is the basic configuration and operation of the film forming apparatus 1. Next, a uniformizing unit for uniformizing the temperature of the flexible lip portion 22 will be described. 11 is an AA end view of FIG. In FIG. 11, the display of the closing member 66 is omitted. Please refer to FIG. 3 and FIG.

  In the adjustment unit 16, each component is made of a metal material, that is, a material having a relatively high heat transfer coefficient, and each component is not heated by the heater 56 like the die 10. Therefore, the adjustment unit 16 functions as a heat radiating member for the die 10, particularly the flexible lip portion 22 thereof.

  Due to the size of the adjustment unit 16, the adjustment unit 16 cannot be arranged so that the connecting members 38 are arranged without a gap in the circumferential direction. Therefore, a plurality of adjustment units 16 that function as heat radiating members are connected to the overhanging surrounding portion 29 of the flexible lip portion 22 at intervals in the circumferential direction.

  Here, a case where there is no heat dissipation member 68 is considered. In this case, since the heat radiating member (adjustment unit 16) is connected to the overhang surrounding portion 29 at intervals in the circumferential direction, the temperature of the overhang surrounding portion 29 becomes uneven in the circumferential direction. Specifically, a portion to which the adjustment unit 16 that functions as a heat dissipation member is connected (hereinafter referred to as a “connection portion”) and an adjustment unit 16 that functions as a heat dissipation member are connected to the overhang surrounding portion 29. There is a temperature difference between the non-connected portions (hereinafter referred to as “non-connected portions”). Then, the main body portion 28 of the flexible lip portion 22 also corresponds to the portion corresponding to the connecting portion of the overhang surrounding portion 29 (that is, the radially inner side of the connecting portion) and the non-connecting portion of the overhang surrounding portion 29. A temperature difference occurs between the portions, and as a result, the heat taken away from the molten resin by the main body portion 28 corresponds to the portion corresponding to the connection portion of the overhang surrounding portion 29 and the non-connection portion of the overhang surrounding portion 29. There is a difference between parts That is, the temperature of the molten resin extruded from the die 10 is not uniform in the circumferential direction. When the temperature of the molten resin becomes nonuniform in the circumferential direction, the timing at which the molten resin solidifies becomes nonuniform in the circumferential direction, and the film thickness becomes nonuniform in the circumferential direction.

  On the other hand, in the present embodiment, the heat radiating member 68 is connected to the unconnected portion of the overhang surrounding portion 29. That is, the connecting member 38 and the heat radiating member 68 of the adjustment unit 16 are alternately connected to the overhang surrounding portion 29 in the circumferential direction with almost no gap. Accordingly, since the heat radiating member is connected to the overhanging surrounding portion 29 in both the connecting portion and the non-connecting portion, the temperature of the overhanging surrounding portion 29 and the flexible lip portion 22 is compared with the case where the heat radiating member 68 is not provided. Becomes more uniform in the circumferential direction.

  The heat dissipation member 68 of the present embodiment includes a first member 78 and a second member 79. The first member 78 is a member that is substantially the same as the connecting member 38 of the adjustment unit 16 (that is, the shape, size, and material are the same in design). The second member 79 is a member corresponding to the tip side of the actuating rod 36, that is, the portion to which the connecting member 38 is attached. Specifically, the second member 79 only needs to include a portion with which the engaging portion 48 of the coupling member 38 of the concave engaging portion 46 of the operating rod 36 of the adjusting unit 16 engages (contacts). .

  The adjustment unit 16 is connected (contacted) to and supported by the medium diameter portion 26 and the large diameter portion 27 in addition to the overhang surrounding portion 29. On the other hand, the heat radiating member 68 is connected (contacted) only to the overhang surrounding portion 29 and is supported only by the overhang surrounding portion 29.

  As described above, according to the film forming apparatus 1 according to the present embodiment described above, the connecting member 38 and the heat radiating member 68 of the adjustment unit 16 are substantially spaced in the circumferential direction in the overhang surrounding portion 29 of the flexible lip portion 22. Are connected alternately. That is, some heat radiating member is connected to the projecting surrounding portion 29 in the circumferential direction with almost no gap. Thereby, compared with the case where there is no heat radiating member 68, the temperature of the overhanging surrounding portion 29 becomes more uniform in the circumferential direction, and as a result, the temperature of the molten resin extruded from the die 10 becomes more uniform in the circumferential direction. The film thickness becomes more uniform in the circumferential direction.

  Further, according to the film forming apparatus 1 according to the present embodiment, since the heat radiating member 68 is connected only to the overhanging surrounding portion 29, it is also connected to the medium diameter portion 26 and the large diameter portion 27. In comparison, the heat of the overhang surrounding portion 29 is dissipated. Therefore, compared with the case where the heat radiating member 68 is also connected to the medium diameter portion 26 and the large diameter portion 27, the adjustment unit 16 reduces the amount of heat that the heat radiating member 68 takes away from the overhang surrounding portion 29. The amount of heat taken away from the surrounding portion 29 can be approached. As a result, the temperature of the molten resin extruded from the die 10 becomes more uniform in the circumferential direction, and the film thickness becomes more uniform in the circumferential direction.

  Further, according to the film forming apparatus 1 according to the present embodiment, the first member 78, which is one of the constituent parts of the heat radiating member 68, is the same as the connecting member 38, which is one of the constituent parts of the adjustment unit 16, so As a result, the manufacturing cost of the member 68 and the film forming apparatus 1 can be reduced.

  The configuration and operation of the film forming apparatus according to the embodiment have been described above. It is to be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective components, and such modifications are within the scope of the present invention.

(Modification 1)
FIG. 12 is an end view showing the heat dissipating member 68 and its periphery according to a modification. FIG. 12 corresponds to FIG. In this modification, the heat radiating member 68 extends to above the bearing members 40 of the two adjacent adjusting units 16 and is placed on them. Specifically, the second member 79 extends to above the bearing member 40. For example, as shown in FIG. 12, the second member 79 extends to above the bearing member 40 while being bent, and is placed on the bearing member 40. Note that the heat radiating member is merely placed on the bearing member 40 and is not fixed to the bearing member 40 so as not to hinder the elastic deformation of the flexible lip portion 22.

  According to this modification, the heat radiating member 68 is supported at two locations, that is, the overhang surrounding portion 29 and the bearing member 40 of the two adjacent adjustment units 16. The heat dissipation member 68 is stably held as compared with the case where it is supported only by the above.

(Modification 2)
FIGS. 13A and 13B are end views showing the heat dissipating member 68 and its surroundings according to another modification, respectively. FIGS. 13A and 13B respectively correspond to FIG. The heat dissipating member 68 protrudes downward and engages with the engaging groove 52, and extends in the vertical direction on the outer side in the radial direction from the overhang surrounding portion 29, and comes into contact with the upper surface of the medium diameter portion 26. The extending portion 97 includes a connecting portion 98 that connects the engaging portion 96 and the extending portion 97. For example, the heat radiating member 68 is press-fitted into the overhanging surrounding portion 29 so that the overhanging surrounding portion 29 is sandwiched between the engaging portion 96 and the extending portion 97, so that the overhanging surrounding portion 29. Fixed against.

  In the example of FIG. 13A, the extending portion 97 includes an upper portion 97a, a lower portion 97b positioned below the upper portion 97a, and an elastic hinge portion that connects the upper portion 97a and the lower portion 97b. 97c. The lower portion 97 b abuts on the upper surface of the medium diameter portion 26 of the outer peripheral member 14 of the die 10.

  The elastic hinge portion 97 c is configured to be elastically deformable with the elastic deformation of the flexible lip portion 22. Specifically, for example, the elastic hinge portion 97c is formed such that at least the thickness in the radial direction is thinner than the thickness of the upper portion 97a and the lower portion 97b. Thereby, even if the lower end of the extending portion 97 of the heat dissipation member 68 is in contact with the upper surface of the medium diameter portion 26, the elastic deformation of the flexible lip portion 22 is not hindered.

  In the example of FIG. 13B, the lower end portion of the extending portion 97 is formed in a circular shape in a longitudinal sectional view. The lower end portion of the extending portion 97 may be formed in a hemispherical shape. When the flexible lip portion 22 is elastically deformed, the heat dissipation member 68 tilts. At this time, the lower end portion of the extending portion 97 of the heat dissipation member 68 rolls on the upper surface of the medium diameter portion 26. In other words, the heat radiating member 68 can be tilted by forming the lower end portion in a circular shape in cross-sectional view so that the lower end portion of the extending portion 97 can make rolling contact with the upper surface of the medium diameter portion 26. Therefore, even if the lower end of the extending portion 97 of the heat dissipation member 68 is in contact with the upper surface of the medium diameter portion 26, the elastic deformation of the flexible lip portion 22 is not hindered.

  According to these modified examples, the heat radiating member 68 is supported at two locations of the overhang surrounding portion 29 and the medium diameter portion 26, and therefore, the heat dissipating member 68 is supported only by the overhang surrounding portion 29. In comparison, the heat dissipation member 68 is stably held.

(Modification 3)
Although not particularly mentioned in the embodiment and the above-described modification, in order to make the temperature of the overhanging surrounding portion 29 and the flexible lip portion 22 more uniform, the heat radiating member 68 and the adjusting unit 16 functioning as a heat radiating member are provided. It is preferable that the heat dissipation performance (ie, thermal resistance) of the

  Therefore, the material, size, and shape of the heat radiating member 68 (shape that increases the surface area) are determined so that the heat resistance of the heat radiating member 68 is closer to the heat resistance of the adjusting unit 16 and preferably the same. do it.

  For example, by configuring the heat dissipating member 68 with a material having a smaller thermal resistance than the adjustment unit 16, the heat dissipating member 68 smaller than the adjustment unit 16 can realize substantially the same heat resistance as the adjustment unit 16, or Compared with the case where the heat radiating member 68 is made of the same material, the thermal resistance can be made closer to the adjustment unit 16.

  Since the heat radiating member 68 is not loaded, the material, size, and shape of the heat radiating member 68 can be determined without considering the strength of the heat radiating member 68.

(Modification 4)
The film forming apparatus 1 may include a heat insulating material as a uniformizing unit instead of or in addition to the heat radiating member 68. The heat insulating material may be provided between the operating rod 36 and the connecting member 38 of the adjustment unit 16 and the flexible lip portion 22 so that the adjustment unit 16 does not contact the flexible lip portion 22. According to this modification, the heat of the flexible lip portion 22 is not transferred to the adjustment unit 16, so that the adjustment unit 16 is connected to the overhang surrounding portion 29 with an interval in the circumferential direction. The occurrence of a temperature difference in the circumferential direction at the exit surrounding portion 29 is suppressed, and as a result, the film thickness becomes more uniform in the circumferential direction.
(Modification 5)
In the embodiment, the case where the film thickness is partially changed in the circumferential direction by widening or narrowing the radial gap of the discharge port 18a of the slit 18 by the adjustment unit 16 has been described. Not limited. The film thickness may be partially changed in the circumferential direction by partially changing at least one of the air volume and the temperature of the cooling air blown from the cooling device 3 in the circumferential direction. In this case, the cooling device 3 may include a plurality of valves and a plurality of heaters in the air ring 8 for adjusting the air volume.

  Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment generated by the combination has the effects of the combined embodiment and the modified examples. In addition, it should be understood by those skilled in the art that the functions to be fulfilled by the constituent elements described in the claims are realized by the individual constituent elements shown in the embodiments and the modified examples or by their linkage. .

  DESCRIPTION OF SYMBOLS 1 Film forming apparatus, 2 Film thickness adjustment part, 10 die | dye, 14 outer peripheral member, 16 adjustment unit, 18a discharge outlet, 22 flexible lip part, 68 heat dissipation member.

Claims (5)

A die that extrudes molten resin in a tube shape from an annular discharge port;
A film thickness adjusting unit for adjusting the film thickness of the molten resin extruded from the discharge port,
The die includes a lip portion that defines an outer periphery of the discharge port,
The film thickness adjusting unit is
A plurality of adjusting units arranged so as to surround the lip part, each of which adjusts the radial width of the discharge port by elastically deforming the lip part; and
And a uniformizing means for uniformizing the temperature of the lip portion. The plurality of adjustment units are connected to the lip portion at intervals in the circumferential direction,
The film forming apparatus according to claim 1, wherein the uniformizing unit includes a heat radiating member connected to the lip portion between adjacent adjustment units.   The film forming apparatus according to claim 2, wherein the heat radiating member is connected only to the lip portion.   The film forming apparatus according to claim 2, wherein the heat radiating member is supported by the lip portion and an adjacent adjusting unit.   The film forming apparatus according to claim 2, wherein the heat radiating member is supported by the lip portion and the portion of the die that is radially outward from the lip portion.

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