Die for extrusion molding, film manufacturing device, and film manufacturing method

Abstract

When a virtual line passing through the center of the resin introduction part 31 and extending in the Y direction to the opening part 25 is defined as a central axis 32c, the boundary BL34 between the junction land part 33 and the junction land part 34 includes: a region R1 including a portion intersecting the central axis 32c; a region R2 located between the region R1 and one end of the boundary between the land 33 and the land 34 in the X direction; and a region (R3) located between the region (R1) and the other end of the boundary between the land section (33) and the land section (34) in the X direction. The flow path length (FPL1) from the boundary between the land section (33) and the land section (34) to the opening section (25) gradually varies at a first rate of change in region (R2) from the region (R1) side to one end section, gradually varies at a first rate of change in region (R3) from the region (R1) side to the other end section, and varies at a constant rate of change in region (R1) or at a rate of change that is smaller than the first rate of change.

Description

Technical Field

[0001] The present invention relates to an extrusion die, a film production apparatus, and a film production method. Background Art

[0002] Japanese Patent Application Laid-Open No. 2011-173263 (Patent Document 1) describes a technique related to an extrusion molding die.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-173263 Summary of the Invention

[0006] A film (resin film) can be produced by extrusion molding. In this case, it is desired to produce a film having a uniform thickness.

[0007] Other problems and new features will become clear from the description of the specification and the accompanying drawings.

[0008] An extrusion molding die according to one embodiment includes: a first opening for supplying molten resin; a second opening for discharging the molten resin; and a resin flow path extending from the first opening to the second opening. The resin flow path includes: a resin inlet connected to the first opening; a manifold connected to the resin inlet; and a first land portion and a second land portion, arranged sequentially between the manifold portion and the second opening in a first direction from the manifold toward the second opening. The second opening extends in a second direction orthogonal to the first direction. The thickness of the second land portion differs from that of the first land portion. With an imaginary line passing through the center of the resin inlet and extending in the first direction to the second opening as a first central axis, the boundary between the first and second land portions includes: a first region including a portion intersecting the first central axis; a second region located between one end of the boundary between the first and second land portions in the second direction and the first region; and a third region located between the other end of the boundary between the first and second land portions in the second direction and the first region. The first flow path length from the boundary between the first connecting platform and the second connecting platform to the second opening gradually changes at a first rate of change from the first region side to the one end portion in the second region, gradually changes at the first rate of change from the first region side to the other end portion in the third region, and remains constant or changes at a rate of change smaller than the first rate of change in the first region.

[0009] Another embodiment of an extrusion molding die includes: a first opening for supplying molten resin; a second opening for discharging the molten resin; and a resin flow path extending from the first opening to the second opening. The resin flow path includes: a resin inlet connected to the first opening; a manifold connected to the resin inlet; and a connecting platform arranged between the manifold and the second opening so as to connect to the manifold in a first direction. The second opening extends in a second direction orthogonal to the first direction. The thickness of the connecting platform is less than or equal to the thickness of the manifold. With an imaginary line passing through the center of the resin inlet and extending in the first direction to the second opening as a first central axis, the boundary between the manifold and the connecting platform includes: a first region including a portion intersecting the first central axis; a second region located between one end of the boundary between the manifold and the connecting platform in the second direction and the first region; and a third region located between the other end of the boundary between the manifold and the connecting platform in the second direction and the first region. The length of the first flow channel from the boundary between the manifold portion and the connecting platform portion to the second opening gradually decreases at a first rate of change from the first region side to the one end portion in the second region, gradually decreases at the first rate of change from the first region side to the other end portion in the third region, and is constant or changes at a rate of change smaller than the first rate of change in the first region.

[0010] According to the aforementioned embodiment, a film having a uniform thickness can be produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is an explanatory diagram showing a schematic configuration of an extrusion molding device according to one embodiment.

[0012] Figure 2 This is an enlarged cross-sectional view of an extrusion die according to one embodiment.

[0013] Figure 3 This is an enlarged cross-sectional view of an extrusion die according to one embodiment.

[0014] Figure 4 This is a cross-sectional view of an extrusion die according to one embodiment.

[0015] Figure 5 This is a perspective view showing a resin flow path portion of an extrusion die according to one embodiment.

[0016] Figure 6 It is a top view showing a resin flow path portion of an extrusion molding die according to one embodiment.

[0017] Figure 7 To show relative to Figure 6 A plan view of a resin flow path portion of an extrusion molding die according to a comparative example.

[0018] Figure 8 To show from Figure 6 A cross-sectional view showing the cross-sectional shape of a film-shaped molten resin discharged from the die shown.

[0019] Figure 9 To show from Figure 7 A cross-sectional view showing the cross-sectional shape of a film-shaped molten resin discharged from the die shown.

[0020] Figure 10 To show relative to Figure 6 An enlarged plan view of a resin flow path portion of an extrusion molding die according to a modified example of FIG.

[0021] Figure 11 To show relative to Figure 6 An enlarged top view of a resin flow path portion of an extrusion molding die according to another modified example.

[0022] Figure 12 To show relative to Figure 6 A top view of a resin flow path portion of an extrusion molding die according to another modified example.

[0023] Figure 13 For the Figure 12 An enlarged cross-sectional view of line B2-B2.

[0024] Figure 14 To show relative to Figure 12 A top view of a resin flow path portion of an extrusion molding die according to a modified example of FIG.

[0025] Figure 15 To enlarge the Figure 14 An enlarged top view of the periphery of the resin inlet portion.

[0026] Figure 16 To show relative to Figure 6 A top view of a resin flow path portion of an extrusion molding die according to another modified example.

[0027] Figure 17 For the Figure 16 An enlarged cross-sectional view of the C1-C1 line.

[0028] Figure 18 For the Figure 16 An enlarged cross-sectional view of the C2-C2 line.

[0029] Figure 19 To show relative to Figure 6A top view of a resin flow path portion of an extrusion molding die according to another modified example.

[0030] Figure 20 For the Figure 19 An enlarged cross-sectional view of the D1-D1 line.

[0031] Figure 21 For the Figure 19 An enlarged cross-sectional view of the D2-D2 line. DETAILED DESCRIPTION

[0032] Below, the embodiments are described in detail based on the accompanying drawings. In addition, in all drawings used to illustrate the embodiments, components with the same functions are marked with the same reference numerals, and their repeated descriptions are omitted. In addition, in the following embodiments, the description of the same or equivalent parts is not repeated in principle unless otherwise required.

[0033] (Implementation Method)

[0034] <Overall Structure of Membrane Production Equipment>

[0035] Reference Figure 1 The overall structure of a film production apparatus (extrusion molding apparatus, extrusion molding machine) 1 according to the present embodiment will be described. Figure 1 It is an explanatory diagram (side view) showing a schematic configuration of the film production apparatus 1 according to the present embodiment.

[0036] In extrusion molding, a molten resin material (molten resin) is extruded and continuously molded. The molten resin passes through a die (metal mold) to be molded into a predetermined cross-sectional shape (film shape), and after passing through the die, it is cooled and solidified.

[0037] In this application, the term "melting" is not limited to melting by heat but also includes dissolution by solvents, etc. Therefore, "molten resin" encompasses not only melting by heating but also dissolving resin in solvents and melting resin using microwaves. Furthermore, liquid resin is also encompassed within the term "molten resin."

[0038] like Figure 1 As shown, the film production apparatus 1 of the present embodiment includes an extruder (extrusion device) 2 , a die (metal die) 3 , a cooling roll (casting roll) 4 , a touch roll 5 , and a recovery machine (recovery device) 6 .

[0039] The extruder 2 melts the resin material and extrude the molten resin material (molten resin) toward the die 3. The die 3 shapes the molten resin extruded from the extruder 2 into a film (sheet). The cooling roller 4 rapidly cools and solidifies the molten resin discharged from the die 3. The cooling roller 4 can also be regarded as a cooling tool (cooling device) for cooling the molten resin discharged from the die 3. The contact roller 5 clamps the resin between the cooling roller 4 and passes it. There may also be a case where the contact roller 5 is not provided. The recycling machine 6 recycles the resin film solidified by the cooling roller 4 and transports it to a winder (not shown). The extruder 2 also has a winder (not shown) for winding the resin film transported from the recycling machine 6, and a cutter (not shown) for cutting the wound resin film, but Figure 1 The illustration thereof is omitted.

[0040] Next, the operation of the film production apparatus 1 , in other words, the outline of the film production method using the film production apparatus 1 will be described.

[0041] First, the film manufacturing method of the present embodiment includes a process of supplying a raw material (resin material) from the resin inlet 2a of the extruder 2 into the extruder 2. The resin material supplied into the extruder 2 is heated and melted while being transported forward by the rotation of the screw in the extruder 2, for example. The resin material (molten resin) melted in the extruder 2 is extruded from the front end of the extruder 2 toward the die 3. In other words, the film manufacturing method of the present embodiment includes a process of extruding a molten resin 11 from the extruder 2 and supplying it to the die 3. The molten resin extruded from the extruder 2 is supplied to the die 3, passes through the die 3 (more specifically, passes through the resin flow path portion 23 described later in the die 3), and is discharged from the die 3 to the cooling roller 4. The molten resin supplied from the extruder 2 to the die 3 passes through the die 3 to be formed into a predetermined cross-sectional shape (here, a film shape), but at the stage of being discharged from the die 3, the resin material (resin material formed into a film shape) maintains a molten state. The film manufacturing method of the present embodiment includes a process of forming the molten resin 11 into a film shape using the die 3. Therefore, Figure 1The molten resin 11 discharged from the mold 3 shown is a molten resin formed into a film shape (film-shaped molten resin, molten resin film). The molten resin 11 discharged from the mold 3 reaches the rotating cooling roller 4, and is rapidly cooled and solidified while rotating with the cooling roller 4 in a state of being attached to the surface of the cooling roller 4. In other words, the film manufacturing method of this embodiment includes a process of cooling the film-shaped molten resin 11 discharged from the mold 3. When a contact roller 5 is provided, the molten resin 11 or resin film 11a passes through the narrow space (gap) between the cooling roller 4 and the contact roller 5. The molten resin 11 discharged from the mold 3 is solidified by the cooling roller 4 and becomes a solidified resin film 11a, which is recovered by the recovery machine 6 and conveyed to the stretching processing machine 7. The resin film 11a conveyed to the stretching processing machine 7 is subjected to a stretching process (elongation process). The stretched resin film 11a is conveyed to a winder (not shown). The resin film 11a conveyed to the winder is wound into a roll and cut by a cutting machine (not shown) as needed. In addition, Figure 1 , the steel sheet may be conveyed to a coiler (not shown) without being subjected to a stretching process.

[0042] <Mold>

[0043] Next, refer to Figure 2-Figure 6 The structure of the extrusion die 3 according to this embodiment will be described. Figure 2-Figure 4 It is a cross-sectional view of the extrusion molding die 3 of this embodiment. Figure 5 It is a perspective view showing the resin flow path portion 23 of the extrusion molding die 3 according to the present embodiment. Figure 6 It is a plan view showing the resin flow path portion 23 of the extrusion molding die 3 according to the present embodiment. Figure 2 Roughly corresponds to Figure 5 and Figure 6 An enlarged cross section of the mold 3 at the position of the A1-A1 line is shown. Figure 3 Roughly corresponds to Figure 5 and Figure 6 An enlarged cross section of the mold 3 at the position of the A2-A2 line is shown. Figure 4 Roughly corresponds to Figure 5 and Figure 6 A cross section of the mold 3 is shown at the position of the A3-A3 line.

[0044] In addition, Figure 2-Figure 6The X direction, Y direction and Z direction are shown. The X direction, Y direction and Z direction are directions that intersect with each other, more specifically, directions that are orthogonal to each other. The X direction and the Y direction are orthogonal to each other, and the Z direction is orthogonal to the X direction and the Y direction. The Y direction is the direction from the manifold portion 32 toward the opening portion 25. Therefore, the direction in which the molten resin mainly flows in the connecting platform portions 33, 34, and 35 of the resin inlet portion 31 is the Y direction. The extension direction (long side direction) of the opening portion 25 is the X direction. The width direction of the manifold portions 32, 34, and 35 of the resin inlet portion 31 is the X direction. In addition, the film-like molten resin 11 (refer to Figure 1 ) is also the X direction. The Z direction is the thickness direction of the connecting platforms 33, 34, and 35 of the resin introduction portion 31. In addition, the thickness direction of the film-shaped molten resin 11 discharged from the opening 25 is also the Z direction. Therefore, in the following description, the connecting platforms 33, 34, and 35, the opening 25, and the molten resin 11 (see Figure 1 ) corresponds to the thickness (size) in the Z direction.

[0045] like Figure 2 and Figure 3 As shown, the mold 3 has a pair of mold parts (mold body, metal mold) 21 and 22. The mold parts 21 and 22 are preferably made of metal materials. The mold parts 21 and 22 are fixed to each other by fixing members such as bolts (not shown).

[0046] A resin flow channel 23 is formed within the mold 3. This channel is formed between the mold sections 21 and 22. This is the space between the mold sections 21 and 22 where the molten resin supplied (introduced) into the mold 3 can flow (move). The resin flow channel 23 can be considered a flow channel formed within the mold 3 through which the molten resin passes. The resin flow channel 23 is surrounded by the mold sections 21 and 22.

[0047] Therefore, the mold 3 includes mold members 21 and 22, a resin flow path 23 formed between the mold members 21 and 22, and fixing members (bolts, etc.) for mutually fixing the mold members 21 and 22. The mold 3 is a so-called T-mold.

[0048] The mold 3 also has an opening (supply port, introduction port) 24 for supplying (introducing) molten resin into the mold 3, and an opening (discharge port) 25 for discharging the molten resin to the outside of the mold 3. The resin flow path 23 is a flow path (a flow path for the molten resin) from the molten resin supplied from the opening 24 to the molten resin discharged from the opening 25. The molten resin supplied from the extruder 2 to the opening 24 of the mold 3 passes through the resin flow path 23 and is discharged from the opening 25 to the outside of the mold 3. Therefore, the mold 3 has the opening 24 for supplying the molten resin, the opening 25 for discharging the molten resin, and the resin flow path 23 from the opening 24 to the opening 25.

[0049] Next, refer to Figure 2-Figure 6 The resin flow path portion 23 will be described in detail.

[0050] The resin flow channel portion 23 includes a manifold portion 32, a resin inlet portion 31 that guides molten resin supplied (introduced) from the opening portion 24 toward the manifold portion 32, and a slit portion connected to the manifold portion 32. The slit portion has three regions (connection platforms 33, 34, and 35) of varying thicknesses. In other words, the resin flow channel portion 23 includes the resin inlet portion 31, the manifold portion 32, and the connection platforms (slit portions, regions) 33, 34, and 35. The resin inlet portion 31, the manifold portion 32, the connection platforms 33, the connection platforms 34, and the connection platforms 35 are arranged in sequence along the direction of molten resin flow. Therefore, the connection platforms 33, 34, and the connection platforms 35 are arranged in sequence between the manifold portion 32 and the opening portion 25, extending from the manifold portion toward the opening portion 25 (i.e., in the Y direction).

[0051] Opening 24, serving as an inlet for the molten resin in mold 3, is connected to resin inlet 31, while opening 25, serving as an outlet for the molten resin in mold 3, is connected to connecting platform 35. Opening 25 is formed by connecting platform 35 reaching the surface of mold 3. Specifically, the downstream end surface of connecting platform 35 serves as opening 25. Therefore, the shape of opening 25 is substantially identical to the cross-sectional shape of connecting platform 35 (a cross-sectional shape approximately perpendicular to the Y direction), and the thickness of opening 25 (the dimension in the Z direction) is substantially identical to the thickness (in the Z direction) of connecting platform 34.

[0052] The shape (planar shape) of the opening 25 is preferably a rectangle. Accordingly, the cross-sectional shape (cross-sectional shape approximately perpendicular to the Y direction) of the connecting platform 35 is preferably a rectangle. Therefore, the opening 25 has a major axis (long side) and a minor axis (short side), with the X direction being the major axis (long side) and the Z direction being the minor axis (short side).

[0053] From the extruder 2 (refer to Figure 1 ) extruded molten resin 11 (refer to Figure 1) flows in from the opening 24 of the mold 3, passes through the resin inlet portion 31, the manifold portion 32, the connecting platform portion 33, the connecting platform portion 34 and the connecting platform portion 35 in sequence, and is discharged from the opening 25 of the mold 3.

[0054] The thickness of the formed resin film 11a can be controlled by the thickness of the opening 25 (the thickness of the connecting platform 34), the flow rate (flow velocity) of the molten resin 11 discharged from the opening 25 of the mold 3, and the recovery speed (rotation speed) of the cooling roller 4. Even if the thickness of the opening 25 (the thickness of the connecting platform 34) is not changed, the smaller the flow rate (flow velocity) of the molten resin 11 discharged from the opening 25 of the mold 3 becomes, the thinner the thickness of the formed resin film 11a becomes. In addition, the cooling roller 4 (see Figure 1 ) becomes faster, the thickness of the formed resin film 11a becomes thinner. The opening 25 can function as a lip (lip opening) for discharging molten resin, and the connecting platform 35 can function as a lip connecting platform.

[0055] The manifold portion 32 extends in the X direction and is connected to the resin introduction portion 31 near the center of the manifold portion 32 (near the center in the X direction). Figure 1 ) The molten resin 11 supplied to the opening 24 of the mold 3 (see Figure 1 ) flows into the manifold portion 32 through the resin introduction portion 31. The molten resin 11 flowing into the manifold portion 32 from the resin introduction portion 31 can move in the manifold portion 32 along the extension direction of the manifold portion 32 (here, the X direction) and can move to both ends of the manifold portion 32. Therefore, the molten resin 11 flowing into the manifold portion 32 from the resin introduction portion 31 (refer to Figure 1 ) spreads in the lateral direction (X direction) within the manifold portion 32. The manifold portion 32 guides the molten resin 11 flowing from the resin inlet portion 31 toward both ends of the manifold portion 32. The molten resin 11 spreads throughout the manifold portion 32, and thus moves from the entire manifold portion 32 toward the connecting platform portion 33. The cross-sectional shape of the manifold portion 32 (the cross-sectional shape approximately perpendicular to the X direction) can be, for example, circular, and accordingly, the three-dimensional shape of the manifold portion 32 can be, for example, cylindrical.

[0056] Connecting platform 33 is integrally connected to manifold 32, connecting platform 34 is integrally connected to manifold 32, and connecting platform 35 is integrally connected to connecting platform 34. Therefore, in the Y direction, connecting platform 33 is positioned adjacent to manifold 32, connecting platform 34 is positioned adjacent to connecting platform 33, and connecting platform 35 is positioned adjacent to connecting platform 34. However, connecting platform 33 is positioned downstream of manifold 32, connecting platform 34 is positioned downstream of connecting platform 33, and connecting platform 35 is positioned downstream of connecting platform 34.

[0057] In this embodiment, the downstream side refers to the molten resin 11 (see Figure 1 ) is the downstream side of the flow of the molten resin 11, and the upstream side means the upstream side of the flow of the molten resin 11. Accordingly, the side close to the opening 25 is the downstream side, and the side away from the opening 25 is the upstream side.

[0058] The molten resin 11 flowing from the resin inlet 31 into the manifold 32 spreads throughout the manifold 32 and flows from the entire manifold 32 into the connection platform 33. The molten resin flowing from the manifold 32 into the connection platform 33 flows through the connection platform 33 into the connection platform 34, then flows through the connection platform 34 into the connection platform 35, and then flows through the connection platform 35 to be discharged from the opening 25 to the outside of the mold 3.

[0059] The connection platforms 33, 34, and 35 have a slit-like (plate-like) shape including a plane (main surface) substantially parallel to the directions X and Y. The thickness relationship of the connection platforms 33, 34, and 35 is as follows.

[0060] That is, Figure 3 As shown, the thickness t2 of the connecting platform 34 is smaller than the thickness t1 of the connecting platform 33 (t1>t2), and the thickness t3 of the connecting platform 35 is smaller than the thickness t2 of the connecting platform 34 (t2>t3). In addition, the thickness of the connecting platform 33 is uniform, the thickness of the connecting platform 34 is uniform, and the thickness of the connecting platform 35 is uniform.

[0061] Taking thicknesses t1, t2, and t3 as an example, thickness t1 is approximately 2-20 mm, thickness t2 is approximately 0.8-10 mm, and thickness t3 is approximately 0.4-6 mm.

[0062] In addition, the dimensions of the resin introduction portion 31 and the manifold portion 32 in the thickness direction (Z direction) relative to the connecting platforms 33, 34, and 35 are as follows. For example, if the cross-sectional shape (cross-sectional shape substantially perpendicular to the X direction) of the manifold portion 32 is circular, its diameter is larger than the thickness t1, t2, and t3 of the connecting platforms 33, 34, and 35, respectively. Therefore, the molten resin 11 (see FIG. 1 ) is larger in the resin introduction portion 31 and the manifold portion 32 than in the connecting platforms 33, 34, and 35. Figure 1 ) is easier to move. According to this, the molten resin is spread throughout the entire manifold portion 32, so that the molten resin 11 can flow from the entire manifold portion 32 into the connecting platform portion 33.

[0063] The widths of the connecting platform 33, the connecting platform 34, and the connecting platform 35 are identical. Therefore, the ends (side surfaces) of the connecting platforms 33, 34, and 35 are aligned with each other and arranged in the Y direction. Furthermore, the ends (side surfaces) of the connecting platforms 33, 34, and 35 are substantially parallel to the Y direction.

[0064] In a plan view, the planar shape of the connecting platform portion 33 is line-symmetrical with respect to the central axis 32c. Furthermore, in a plan view, the planar shape of the connecting platform portion 34 is line-symmetrical with respect to the central axis 32c. Furthermore, in a plan view, the planar shape of the connecting platform portion 35 is line-symmetrical with respect to the central axis 32c. In other words, the connecting platforms 33, 34, and 35 are each symmetrical with respect to the central axis 32c along the Y direction.

[0065] In addition, including the following Figure 19 The connecting platform portion 36 shown, when describing the connecting platform portions 33, 34, 35, 36, "width" refers to the width (size) corresponding to the X direction, "end" refers to the end corresponding to the X direction, "two ends" refers to the two ends corresponding to the X, and "center" or "center" refers to the center corresponding to the X direction. In addition, when describing the connecting platform portions 33, 34, 35, 36, "top view" refers to the case of viewing from above parallel to the X direction and the Y direction, and "planar shape" refers to the planar shape when viewing from above parallel to the X direction and the Y direction. In addition, when describing the connecting platform portions 33, 34, 35, 36, "center axis ( Figure 2 、 Figure 3 ,and Figure 6 The central axis 32c)" shown in FIG. 32 is a straight line passing through the center of the connecting stages 33, 34, 35, and 36 in the X direction and parallel to the Y direction. The central axis 32c is a straight line passing through the center of the connecting stages 33, 34, 35, and 36 in the X direction and parallel to the Y direction. Figure 2 The imaginary line (imaginary straight line) is the center of the resin introduction portion 31 shown. In the example of this embodiment, the opening 24 is provided at the top of the resin introduction portion 31 extending in the Y direction. Therefore, the central axis 32c passes through the center of the opening 24.

[0066] exist Figure 6 In the plan view shown, the boundary BL23 between the manifold portion 32 and the connecting platform portion 33 is parallel to the X direction. Furthermore, in the plan view, the boundary BL45 between the connecting platform portion 34 and the connecting platform portion 35 is parallel to the X direction. Furthermore, the extending direction of the opening portion 25 at the downstream end of the connecting platform portion 35 is parallel to the X direction.

[0067] On the other hand, Figure 6When viewed from above, the boundary BL34 between the connecting platform 33 and the connecting platform 34 is not parallel to the X direction, but includes portions (region R2 and region R3) that are inclined with respect to the X direction. The boundary BL34 between the connecting platform 33 and the connecting platform 34 includes a region R1 that includes a portion that intersects the central axis 32c, a region R2 that is located between one end of the boundary BL34 between the connecting platform 33 and the connecting platform 34 in the X direction and the region R1, and a region R3 that is located between the other end of the boundary BL34 between the connecting platform 33 and the connecting platform 34 in the X direction and the region R1. In the X direction, the region R1 is located at the center of the boundary BL34. Figure 6 In the example shown, the boundary BL34 is parallel to the X direction in the region R1 . In other words, the boundary BL34 is parallel to the extending direction of the opening 25 in the region R1 .

[0068] When focusing on the inclination angles of regions R1, R2, and R3 relative to the X-direction, the following can be expressed. Specifically, in region R2, boundary BL34 is inclined at an angle less than 90 degrees relative to the X-direction. In region R3, boundary BL34 is inclined at an angle less than 90 degrees relative to the X-direction. The angle formed by boundary BL34 with the X-direction in region R1 is smaller than the angle formed by boundary BL34 with the X-direction in regions R2 and R3 (however, this also includes 0 degrees).

[0069] exist Figure 6 In the example shown, the angle between region R2 of boundary BL34 and the X direction is, for example, approximately 1-10 degrees. Furthermore, the angle between region R3 of boundary BL34 and the X direction is the same as the angle between region R2 of boundary BL34 and the X direction, for example, approximately 1-10 degrees.

[0070] Next, the flow path length FPL1 of the resin flow path from the boundary BL34 to the opening 25 in each of the regions R1 , R2 , and R3 will be described. Figure 6The flow path length FPL1 shown is the sum of the flow path length FPL4 of the connecting platform 34 and the flow path length FPL5 of the connecting platform 35. Flow path length FPL3 corresponds to the dimension (length) of the connecting platform 33 in the Y direction, flow path length FPL4 corresponds to the dimension (length) of the connecting platform 34 in the Y direction, and flow path length FPL5 corresponds to the dimension (length) of the connecting platform 35 in the Y direction. In each of the connecting platforms 33, 34, and 35, the molten resin flows (moves) primarily in the Y direction. Therefore, flow path length FPL3 can be considered the dimension (length) of the connecting platform 33 along the direction of the molten resin flow, while flow path length FPL4 can be considered the dimension (length) of the connecting platform 34 along the direction of the molten resin flow. Therefore, flow path length FPL3 defines the flow distance of the molten resin in the connecting platform 33, flow path length FPL4 defines the flow distance of the molten resin in the connecting platform 34, and flow path length FPL5 defines the flow distance of the molten resin in the connecting platform 35.

[0071] In the example of this embodiment, the boundary BL45 between the connecting lands 34 and 35 is parallel to the X-direction, which is the direction in which the opening 25 extends. Consequently, the flow path length FPL5 remains constant regardless of the position in the X-direction. On the other hand, as previously described, the boundary BL34 between the connecting lands 33 and 34 includes a portion that is inclined relative to the X-direction, which is the direction in which the opening 25 extends. Therefore, the flow path length FPL4 of the connecting land 34 is not constant but varies depending on the position in the X-direction. This will be explained in detail below.

[0072] In addition, the flow path length FPL1 from the boundary BL34 to the opening 25 will be described below. As mentioned above, in the case of this embodiment, the flow path length FPL5 is constant regardless of the position in the X direction, so the description of the flow path length FPL1 described below can be replaced with the description of the flow path length FPL4. Figure 6 , the length of the flow channel from region R1 of boundary BL34 to opening 25 along the Y direction within flow channel length FPL1 is shown as flow channel length L1. Furthermore, the length of the flow channel from region R2 of boundary BL34 to opening 25 along the Y direction within flow channel length FPL1 is shown as flow channel length L2. Furthermore, the length of the flow channel from region R3 of boundary BL34 to opening 25 along the Y direction within flow channel length FPL1 is shown as flow channel length L3.

[0073] Specifically, in the X direction, the flow path length FPL1 is the largest (longest) in the region R1 near the center of the boundary BL34. Figure 6 In the example shown, the value of the flow path length L1 is constant regardless of the position in the X direction.

[0074] In region R2 of boundary BL34, the flow path length FPL1 gradually decreases from region R1 to one end of boundary BL34. The angle between region R2 of boundary BL34 and the X-direction is constant. Therefore, the angle between region R2 and the X-direction can be expressed as the rate of change of flow path length FPL1. Specifically, in region R2, flow path length FPL1 (flow path length L2) gradually decreases at a first rate of change from region R1 to one end of boundary BL34.

[0075] In region R3 of boundary BL34, the angle gradually decreases from region R1 to the other end of boundary BL34. The absolute value of the angle between region R3 of boundary BL34 and the X-direction is the same as the absolute value of the angle between region R2 of boundary BL34 and the X-direction and is constant. Therefore, when defining the angle between region R3 and the X-direction as the rate of change of flow channel length FPL1, it can be expressed as follows. That is, in region R3, flow channel length FPL1 (flow channel length L3) gradually decreases from region R1 to the other end of boundary BL34 at the first rate of change described above.

[0076] exist Figure 6 In the case of the die 3 shown, the flow rate distribution of the molten resin in the X direction (width direction) can be made uniform. The reason for this is as follows.

[0077] The molten resin flowing from the resin inlet 31 into the manifold 32 spreads throughout the entire manifold 32, and the molten resin flows from the entire manifold 32 into the connecting platform 33. However, near the center in the X direction, the molten resin flows more easily from the manifold 32 to the connecting platform 33 because it is closer to the resin inlet 31. In contrast, as the manifold 32 moves toward the ends in the X direction, the molten resin tends to flow less easily from the manifold 32 to the connecting platform 33 because it is farther from the resin inlet 31. Consequently, the inflow pressure of the molten resin flowing from the manifold 32 into the connecting platform 33 is higher near the center in the X direction, while the inflow pressure of the molten resin flowing from the manifold 32 into the connecting platform 33 tends to decrease toward the ends in the X direction.

[0078] Here, in the case of mold 3, the flow path length FPL4 of the connecting platform 34 (in the case of this embodiment, it can also be called the total flow path length FPL1 of the connecting platform 34 and the connecting platform 35) is set to the maximum in the area R1 near the center, and is gradually reduced from the area R1 to the two ends (the two ends in the X direction). The thickness t2 of the connecting platform 34 is smaller than the thickness t1 of the connecting platform 33, so it is more difficult for the molten resin to flow in the connecting platform 34 than in the connecting platform 33. That is, when the molten resin flows the same distance in the connecting platform 33 and the connecting platform 34, the flow path resistance in the connecting platform 34 is greater than that in the connecting platform 33. That is, the flow path resistance per unit distance is greater in the connecting platform 34 than in the connecting platform 33. In addition, the flow path resistance per unit distance in the connecting platforms 33, 34, and 35 becomes greater as the thickness becomes smaller.

[0079] By setting the flow path length FPL1 to its maximum in region R1 of boundary BL34 and gradually decreasing from region R1 toward both ends, the combined flow path resistance of connecting platform 33 and connecting platform 34 reaches its maximum in region R1 and gradually decreases from region R1 toward both ends (the ends in the X direction). This allows the inflow pressure of the molten resin flowing from connecting platform 34 into connecting platform 35 to remain approximately constant regardless of its position in the X direction. Specifically, considering that the inflow pressure of the molten resin flowing from manifold 32 into connecting platform 33 gradually decreases from region R1 toward both ends in the X direction, the flow path resistance of the molten resin as it passes through connecting platforms 33 and 34 gradually decreases from the center toward both ends in the X direction. According to this, the unevenness of the flow resistance of the connecting platforms 33 and 34 can be used to offset the unevenness of the inflow pressure of the molten resin when it flows from the manifold portion 32 into the connecting platform 33. As a result, the unevenness of the inflow pressure of the molten resin when it flows from the connecting platform 34 into the connecting platform 35 can be suppressed, and the inflow pressure of the molten resin when it flows into the connecting platform 35 can be kept substantially constant regardless of the position in the X direction. Figure 3 ) is constant regardless of the position in the X direction. Therefore, the flow rate (flow velocity) of the molten resin discharged from the opening 25 located at the downstream end of the connecting platform 35 can be kept substantially constant regardless of the position in the X direction. In other words, the mold 3 can function to provide a uniform flow rate distribution of the molten resin in the X direction (width direction).

[0080] When the flow rate distribution of the molten resin discharged from the opening 25 is uniform, the film thickness of the film-shaped molten resin discharged from the opening 25 becomes uniform. In other words, by using the mold 3 of this embodiment, a film having a uniform thickness can be manufactured. Figure 1In the film manufacturing apparatus shown, in order to make the thickness of the resin film 11a discharged from the recycling machine 6 or the stretching machine 7 uniform, it is necessary to make the thickness of the film-shaped molten resin 11 discharged from the mold 3 uniform. In the case of the mold 3 of this embodiment, the film-shaped molten resin 11 can be molded with a uniform thickness, so the thickness of the resin film 11a discharged from the recycling machine 6 or the stretching machine 7 can be made uniform.

[0081] In addition, Figure 7 In the case of the mold 3C1 of the comparative example shown, there is no Figure 6 The region R1 shown in FIG. 1 is connected to the region R2 and the region R3 at the position intersecting the central axis 32c. Figure 6 The mold 3 shown is different. Figure 7 To show relative to Figure 6 A plan view of a resin flow path portion of an extrusion molding die according to a comparative example. Figure 8 To show from Figure 6 A cross-sectional view showing the cross-sectional shape of a film-shaped molten resin discharged from the die shown. Figure 9 For Figure 7 A cross-sectional view showing the cross-sectional shape of a film-shaped molten resin discharged from the die shown.

[0082] When not considered Figure 7 When the width W31 (length in the X direction) of the resin introduction portion 31 is shown, Figure 7 The mold 3C1 shown in the figure can also make the flow rate distribution of the molten resin in the X direction (width direction) uniform. However, the inventors of this application have found that Figure 7 In the case of the mold 3C1 shown, Figure 9 As shown in the molten resin film 112, the thickness T11c near the center in the X direction is smaller than the thickness T11e near the ends. Figure 8 As shown, in the mold 3 of this embodiment (refer to Figure 6 ) In the case of the molten resin film 111 discharged, the difference between the thickness T11c near the center and the thickness T11e near the ends is small enough to be ignored, and the thickness is uniform.

[0083] Figure 8 The molten resin film 111 shown is relative to Figure 9 The reason why the molten resin film 112 shown has a uniform thickness is as follows.

[0084] That is, in Figure 6 and Figure 7In the portion of the boundary BL34 shown, which overlaps with the resin inlet 31 in the Y direction, the inflow pressure of the molten resin is approximately constant. Strictly speaking, as will be described later, the distribution of the inflow pressure in the X direction may not be constant. However, when comparing the difference between the ends and the center of the region 34 in the X direction, the inflow pressure unevenness is small.

[0085] On the other hand, when focusing on flow resistance, Figure 7 In the case of the mold 3C1 shown, the flow resistance to the molten resin is not constant in the portion overlapping with the resin inlet portion 31 in the Y direction, and the flow resistance increases as the distance from the central axis 32c increases. Therefore, near the center in the X direction, the molten resin 11 discharged from the opening 25 (see Figure 9 ) is smaller than that near both ends in the X direction. Figure 9 In the case of the molten resin film 112 shown in FIG. 1 , the thickness T11c near the center in the X direction is smaller than the thickness T11e near the ends. Figure 7 In the example shown, in the portion overlapping with the resin inlet portion 31, the unevenness of the inflow pressure when the molten resin flows from the manifold portion 32 into the connecting platform portion 33 is poorly balanced with the unevenness of the flow resistance of the connecting platforms 33 and 34, and there is a portion where the flow resistance is excessively large.

[0086] On the other hand, Figure 6 In the case of the mold 3C1 shown, the flow path length FPL1 from the boundary BL34 between the connecting platform 33 and the connecting platform 34 to the opening 25 is constant in the region R1 or changes at a rate smaller than the first rate of change in the regions R2 and R3. Figure 6 In the example shown, in region R1, the flow path length FPL1 is substantially constant. Therefore, in the case of the mold 3, including the portion overlapping with the resin inlet portion 31 in the Y direction, the unevenness of the inflow pressure when the molten resin flows from the manifold portion 32 into the connecting platform portion 33 and the unevenness of the flow path resistance of the connecting platforms 33 and 34 can be balanced at all positions in the X direction. As a result, in the case of the mold 3, even when the width W31 of the resin inlet portion 31 is taken into account, the flow rate distribution of the molten resin in the X direction (width direction) can be made uniform over the entire range. Accordingly, in Figure 8 In the case of the molten resin film 111 shown, the difference between the thickness T11c near the center and the thickness T11e near both ends is negligibly small, and the thickness is uniform.

[0087] <Regarding the scope of area R1>

[0088] Next, Figure 6The relationship between the width WR1 of the region R1 shown and the width W31 of the resin introduction portion 31 will be described. Figure 10 To show relative to Figure 6 An enlarged plan view of a resin flow path portion of an extrusion molding die according to a modified example of FIG. Figure 11 To show relative to Figure 6 An enlarged top view of a resin flow path portion of an extrusion molding die according to another modified example.

[0089] exist Figure 6 In the example shown, the resin introduction portion 31 and the region R1 overlap in the Y direction. The width W31 of the resin introduction portion 31 matches the width WR1 of the region R1. The regions R2 and R3 do not overlap with the resin introduction portion 31 in the Y direction. Figure 6 The embodiment shown can be described as follows. That is, when the region of the boundary BL34 between the connecting platform portion 33 and the connecting platform portion 34 that overlaps with the resin introduction portion 31 in the Y direction is defined as region R4 (refer to Figure 10 and Figure 11 ), the width WR1 of the region R1 in the X direction is equal to the width WR4 of the region R4 (refer to Figure 10 and Figure 11 ) is 100%.

[0090] However, it is not limited to Figure 6 The range of the region R1 shown is in a state where the range completely coincides with the resin introduction portion 31 in the Y direction. The range of the region R1 can be adjusted according to the width W31 of the resin introduction portion 31 .

[0091] In e.g. Figure 10 In the case of the resin flow channel portion 23 of the mold 3M1 shown, the width W31 of the resin inlet portion 31 is wide (for example, about 120-250 mm). In this case, there is a case where the inflow pressure from the resin inlet portion 31 to the manifold portion 32 is different depending on the position in the X direction in the resin inlet portion 31. That is, there is a case where the inflow pressure from the resin inlet portion 31 to the manifold portion 32 is high at a position close to the center axis 32c, and the inflow pressure from the resin inlet portion 31 to the manifold portion 32 becomes low at a position close to the inner wall of the resin inlet portion 31 due to the flow channel resistance from the inner wall. In this case, in the area close to the inner wall of the resin inlet portion 31, the inflow pressure from the connecting platform portion 33 to the connecting platform portion 34 is also relatively easy to become lower than near the center axis 32c.

[0092] Here, in Figure 10In the case of the mold 3M1 shown, a portion of each of region R2 and region R3 overlaps with the resin inlet portion 31 in the Y direction. Since a portion of each of region R2 and region R3 overlaps with the resin inlet portion 31 in the Y direction at a position close to the inner wall of the resin inlet portion 31, the unevenness of the inflow pressure when the molten resin flows from the manifold portion 32 into the connecting platform portion 33 can be balanced with the unevenness of the flow path resistance of the connecting platforms 33 and 34 at all positions in the X direction, including the periphery of the position overlapping with the inner wall of the resin inlet portion 31 in the Y direction.

[0093] On the other hand, in e.g. Figure 11 In the case of the resin flow channel portion 23 of the mold 3M2 shown, the width W31 of the resin inlet portion 31 is narrow (e.g., approximately 30-100 mm). In this case, the molten resin introduced from the resin inlet portion 31 flows into the manifold portion 32 at a high speed. Therefore, the inflow pressure of the resin from the manifold portion 32 to the connecting platform portion 33 may become high within a region wider than the region R4 that overlaps with the resin inlet portion 31 in the Y direction. In this case, even in the region of the boundary BL34 that does not overlap with the resin inlet portion 31, the inflow pressure may be similar to that of the region R1.

[0094] Here, in Figure 11 In the case of the mold 3M2 shown, region R1 is wider than region R4. Specifically, assuming that the region of boundary BL34 between the connecting platform 33 and the connecting platform 34 that overlaps with the resin inlet 31 in the Y direction is region R4, the width WR1 of region R1 in the X direction is greater than 100% of the width WR4 of region R4. The wider range of region R1 relative to region R4 allows for the balance of the unevenness of the inflow pressure of the molten resin flowing from the manifold 32 into the connecting platform 33 and the unevenness of the flow resistance of the connecting platforms 33 and 34 at all locations in the X direction, including the area surrounding region R4 that overlaps with the resin inlet 31 in the Y direction.

[0095] If using Figure 10 and Figure 11As described above, the range of region R1 can be made smaller or larger than the width WR4 of region R4, depending on the width W31 of the resin inlet portion 31. However, near the center axis 32c, there are cases where the pressure of the resin flowing from the manifold portion 32 to the connecting platform portion 33 can be considered to be approximately constant. In this case, the following relationship preferably holds between region R1 and region R4. That is, the range of region R1 is wider than the range of region R4. Specifically, when the region overlapping the resin inlet portion 31 in the Y direction of the boundary BL34 between the connecting platform portion 33 and the connecting platform portion 34 is defined as region R4, the width WR1 of region R1 in the X direction is greater than or equal to 80% and less than or equal to 120% of the width WR4 of region R4.

[0096] <Variation 1>

[0097] Next, use Figure 12 and Figure 13 relative to Figure 6 Other variations of are described below. Figure 12 To show relative to Figure 6 A top view of a resin flow path portion of an extrusion molding die according to another modified example. Figure 13 For the Figure 12 An enlarged cross-sectional view of line B2-B2. Figure 12 and Figure 13 The mold 3M3 shown in FIG. 3M3 has a shape of the resin flow channel portion 23, in particular, no Figure 6 The connection platform 35 shown is the same as Figure 6 The mold 3 shown is different.

[0098] In the case of the mold 3M3, the lower end (end on the downstream side) of the connecting platform 34 is provided with an opening 25. In this case, the connecting platform 34 functions as a lip connecting platform. In the case of the mold 3M3, the connecting platform 34 is provided with an opening 25. Figure 6 The flow path length FPL1 described above is consistent with the flow path length FPL4 of the connecting platform 34. Figure 13 As shown, the thickness t3 of the connecting platform 34 is smaller (thinner) than the thickness t1 of the connecting platform 33. As an example of thicknesses t1 and t3, the thickness t1 is about 2-20 mm, and the thickness t3 is about 0.4-6 mm.

[0099] The flow path length FPL1 from the boundary BL34 between the connecting platform 33 and the connecting platform 34 to the opening 25 is also the same as that of the mold 3M3. Figure 6 The same as the mold 3 described above. That is, in the X direction, in the region R1 near the center of the boundary BL34, the flow path length FPL1 is the largest (longest). Figure 12In the example shown, the value of the flow path length L1 is constant regardless of the position in the X direction. In region R2, the flow path length FPL1 (flow path length L2) gradually decreases at a first rate of change from the region R1 side to one end of the boundary BL34. In region R3, the flow path length FPL1 (flow path length L3) gradually decreases at the aforementioned first rate of change from the region R1 side to the other end of the boundary BL34. Accordingly, in Figure 12 In the case of the die 3M3 shown, it is possible to function to make the flow rate distribution of the molten resin in the X direction (width direction) uniform.

[0100] In addition, Figure 12 and Figure 13 The case of the mold 3M3 shown is compared Figure 6 and Figure 3 The mold 3 shown in FIG. 3 has a thickness t3 of the connecting platform 34 (in Figure 3 In the example shown, the thickness t2 of the connecting platform 34 is narrow. Therefore, the mold 3M3 is larger than the mold 3 in terms of the flow resistance in the connecting platform 34. As a method of reducing the flow resistance of the resin flow path portion 23 as a whole, as shown in FIG. Figure 3 As shown, there is a method of providing a connecting platform 35 that functions as a lip connecting platform on the downstream side of the connecting platform 34. Alternatively, by shortening Figure 12 The flow path length FPL1 shown is used to reduce the flow path resistance.

[0101] use Figure 12 and Figure 13 The mold 3M3 described above has the following differences: Figure 6 The mold 3 shown is the same. Therefore, regarding the structure common to the mold 3, repeated description is omitted.

[0102] In addition, it is possible to use Figure 12 and Figure 13 Explanation of the structure and use of mold 3M3 Figure 10 The structure or use of the mold 3M1 described Figure 11 The structural combination of the mold 3M2 described above is applicable.

[0103] <Variation 2>

[0104] Next, use Figure 13 and Figure 15 relative to Figure 12 Other variations of are described below. Figure 14 To show relative to Figure 12 A top view of a resin flow path portion of an extrusion molding die according to a modified example of FIG. Figure 15 To enlarge the Figure 14 An enlarged top view of the periphery of the resin inlet portion. Figure 14 and Figure 15The shape of the resin flow channel portion 23 of the mold 3M4 shown, in particular, the shape of the region R1 at the boundary BL34 between the connecting platform portion 33 and the connecting platform portion 34 is similar to that of the mold 3M4. Figure 12 The mold 3M3 shown is different. Figure 15 In order to clearly illustrate the situation where the rate of change of the boundary BL34 in region R1 is smaller than the rate of change in region R2 and the rate of change in region R3, the extension line of the side of region R2 and the extension line of the side of region R3 are illustrated as imaginary lines BL34D.

[0105] Specifically, in Figure 14 and Figure 15 In the case of the mold 3M4 shown in FIG. 1 , the region R1 from the boundary BL34 between the connecting platform portion 33 and the connecting platform portion 34 is formed along the Y direction to the opening portion 25 (see FIG. 1 ). Figure 14 ) varies according to the position in the X direction. Figure 6 The mold 3 shown, Figure 10 The mold 3M1 shown, Figure 11 The mold 3M2 shown, and Figure 12 The molds 3M3 shown are each different.

[0106] Like using Figure 10 As described above, when the width W31 of the resin inlet 31 is wide, the inflow pressure of the molten resin from the manifold 32 to the connection platform 33 may differ depending on the position in the X direction within the region R4 overlapping the resin inlet 31. That is, the inflow pressure is relatively high at a position close to the central axis 32c, and the inflow pressure is low near the side wall of the resin inlet 31 due to the influence of the flow resistance of the side wall. Figure 14 and Figure 15 In the case of the mold 3M4 shown, the value of the flow path length FPL1 in region R1 varies depending on the position in the X direction. In this variation, in region R1, boundary BL34 has an arc shape with its vertex at the point where it intersects the central axis 32c. The value of flow path length FPL1 is maximum at the point where it overlaps the central axis 32c. One end of the arc connects to region R2, and the other end connects to region R3.

[0107] However, the amount of change in the inflow pressure of the molten resin in region R1 according to the position in the X direction is smaller than the amount of change in the inflow pressure of the molten resin in regions R2 and R3 according to the position in the X direction. Therefore, in the case of this modified example, the rate of change in the flow path length FPL1 according to the position in the X direction in region R1 is smaller than the rate of change in the flow path length FPL1 in region R2 and the rate of change in the flow path length FPL1 in region R3. This point is compared with Figure 15It can be seen that the angle formed between the illustrated imaginary line BL34D and the X direction is smaller than the angle formed between the boundary BL34 in the region R1 and the X direction.

[0108] In the case of this modification, the slight unevenness of the inflow pressure near the central axis 32c can be offset by the shape of the region R1 of the boundary BL34, so Figure 12 The mold 3M3 shown is able to obtain a more uniform film.

[0109] use Figure 14 and Figure 15 The mold 3M4 described above has the following differences: Figure 12 The mold 3M3 shown is the same. Therefore, regarding the structure common to the mold 3M3, repeated description is omitted.

[0110] In addition, it is possible to use Figure 14 and Figure 15 Explanation of the structure and use of mold 3M4 Figure 6 The structure and use of the mold 3 described Figure 11 The structure and use of the mold 3M2 described Figure 12 The structural combination of the mold 3M3 described above is applicable.

[0111] In addition, this modification shows an example in which the shape of region R1 of boundary BL34 is an arc as an embodiment in which the rate of change of boundary BL34 in region R1 is smaller than the rate of change in region R2 and the first rate of change in region R3. However, the shape of region R1 of boundary BL34 is not limited to an arc, and various modifications can be applied within a range that satisfies the condition that the rate of change of boundary BL34 in region R1 is smaller than the rate of change in region R2 and the first rate of change in region R3.

[0112] <Variation 3>

[0113] Next, use Figure 15 、 Figure 17 ,and Figure 18 relative to Figure 6 Other variations of are described below. Figure 16 To show relative to Figure 6 A top view of a resin flow path portion of an extrusion molding die according to another modified example. Figure 17 For the Figure 16 An enlarged cross-sectional view of the C1-C1 line. Figure 18 For the Figure 16 An enlarged cross-sectional view of the C2-C2 line. Figure 16 The cross section of the C3-C3 line shown is Figure 4 The same as above, so the illustration is omitted. Figure 16-18The mold 3M5 shown has a shape of the resin flow channel portion 23, especially a thickness t1 of the connecting platform portion 33 (see Figure 18 ) than the thickness t2 of the connecting platform 34 (refer to Figure 18 ) small (thin) and the shape of the boundary BL34 Figure 6 The mold 3 shown is different.

[0114] Specifically, if Figure 18 As shown, the connection platforms 33, 34, and 35 have a slit-like (plate-like) shape having a plane (main surface) substantially parallel to the X and Y directions. The thickness relationship of the connection platforms 33, 34, and 35 is as follows.

[0115] That is, Figure 3 As shown, the thickness t2 of the connecting platform 34 is greater than the thickness t1 of the connecting platform 33 (t1 < t2), and the thickness t3 of the connecting platform 35 is smaller than the thickness t2 of the connecting platform 34 (t2 > t3). Furthermore, the thickness of the connecting platform 33 is uniform, the thickness of the connecting platform 34 is uniform, and the thickness of the connecting platform 35 is uniform. As an example of thicknesses t1, t2, and t3, thickness t1 is approximately 2-20 mm, thickness t2 is approximately 0.4-6 mm, and thickness t3 is approximately 0.8-10 mm.

[0116] In this variation, the thickness t2 of land portion 34 is greater than the thickness t1 of land portion 33. Therefore, molten resin flows more easily on land portion 34 than on land portion 33. Specifically, when molten resin flows the same distance on land portions 33 and 34, the flow resistance on land portion 34 is smaller than on land portion 33. In other words, the flow resistance per unit distance is smaller on land portion 34 than on land portion 33. Furthermore, as previously mentioned, the smaller the thickness of land portions 33, 34, and 35, the greater the flow resistance per unit distance.

[0117] In this modification, the thickness t1 of the connecting platform 33 and the thickness t2 of the connecting platform 34 are as described above. Figure 2 The mold 3 shown is different, and therefore the shape of the boundary BL34 needs to be different accordingly.

[0118] Specifically, in the X direction, the flow path length FPL1 is the smallest (shortest) in region R1 near the center of the boundary BL34. Figure 16 In the example shown, the value of the flow path length L1 is constant regardless of the position in the X direction.

[0119] In region R2 of boundary BL34, the flow path length FPL1 gradually increases from region R1 toward one end of boundary BL34. The angle between region R2 and the X-direction is constant. Therefore, if the angle between region R2 and the X-direction is defined as the rate of change of flow path length FPL1, it can be expressed as follows. Specifically, in region R2, flow path length FPL1 (flow path length L2) gradually increases at a first rate of change from region R1 toward one end of boundary BL34.

[0120] In region R3 of boundary BL34, the angle gradually increases from region R1 toward the other end of boundary BL34. The absolute value of the angle formed between region R3 of boundary BL34 and the X-direction is the same as the absolute value of the angle formed between region R2 of boundary BL34 and the X-direction and is constant. Therefore, when the angle formed between region R3 and the X-direction is defined as the rate of change of flow channel length FPL1, it can be expressed as follows. That is, in region R3, flow channel length FPL1 (flow channel length L3) gradually increases from region R1 toward the other end of boundary BL34 at the first rate of change described above.

[0121] Figure 16 The case of mold 3M5 shown is also the same Figure 6 The mold 3 shown in FIG. 1 is the same as the one shown in FIG. 1 , and can function to make the flow rate distribution of the molten resin in the X direction (width direction) uniform. The reason for this is the same as using Figure 6 The reasons for the above are the same. In this modification, Figure 6 Different points are explained.

[0122] In the case of this modification, if Figure 17 As shown, the thickness t1 of the connecting platform 33 is smaller than the thickness t2 of the connecting platform 34. Therefore, from the perspective of facilitating the flow of molten resin, the following can be explained. Specifically, the molten resin flows more easily in the connecting platform 34 than in the connecting platform 33. In other words, the flow resistance of the connecting platform 33 is greater than that of the connecting platform 34.

[0123] In the case of the mold 3M5 of this modified example, the flow path length FPL4 of the connecting platform 34 (in this modified example, it can be considered the combined flow path length FPL1 of the connecting platform 33 and the connecting platform 34) is minimized in region R1 near the center and gradually increases from region R1 to both ends (both ends in the X direction). The flow path length FPL1 is minimized in region R1 of the boundary BL34 and gradually increases from region R1 to both ends. As a result, the combined flow path resistance of the connecting platform 33 and the connecting platform 34 is maximized in region R1 and gradually decreases from region R1 to both ends (both ends in the X direction). This allows the inflow pressure of the molten resin flowing from the connecting platform 34 to the connecting platform 35 to be maintained substantially constant regardless of the position in the X direction.

[0124] Thus, it is possible to suppress the unevenness of the inflow pressure of the molten resin when it flows from the connecting platform 34 into the connecting platform 35, and to keep the inflow pressure of the molten resin when it flows into the connecting platform 35 substantially constant regardless of the position in the X direction. Figure 3 ) is constant regardless of the position in the X direction. Therefore, the flow rate (flow velocity) of the molten resin discharged from the opening 25 located at the downstream end of the connecting platform 35 can be kept substantially constant regardless of the position in the X direction. In other words, in the case of the mold 3M5, the flow rate distribution of the molten resin in the X direction (width direction) can be uniform.

[0125] use Figure 16-18 The mold 3M5 described above has the following differences: Figure 6 The mold 3 shown is the same. Therefore, regarding the structure common to the mold 3, repeated description is omitted.

[0126] In addition, it is possible to use Figure 16-18 Explanation of the structure and use of mold 3M5 Figure 10 Explanation of the structure and use of mold 3M1 Figure 11 Explanation of the structure and use of mold 3M2 Figure 12 The structure and use of the mold 3M3 described Figure 14 The structure and combination application of mold 3M4 are described.

[0127] In combining this modification with the Figure 10 The structure and use of the mold 3M1 described Figure 11 In the case of the structural combination of the mold 3M2 described above, it is preferable to satisfy the following relationship. Figure 10 or Figure 11 As shown, when the region R4 in the boundary BL34 between the connecting platform 33 and the connecting platform 34 that overlaps with the resin introduction portion 31 in the Y direction, the width WR1 of the region R1 in the X direction is 80% or more and 120% or less of the width WR4 of the region R4. Figure 10 and Figure 11 As mentioned above.

[0128] In addition, when combining this modification with the Figure 14 In the case of the structure combination of the mold 3M4 described above, the flow path length FPL1 is the minimum value at the position where the boundary BL34 overlaps the central axis 32c. In the case of combination with this modification, the shape of the region R1 of the boundary BL34 is not limited to the arc shape as described above.

[0129] <Variation 4>

[0130] Next, use Figure 18 、 Figure 20 ,and Figure 21 relative to Figure 6 Other variations of are described below. Figure 19 To show relative to Figure 6 A top view of a resin flow path portion of an extrusion molding die according to another modified example. Figure 20 For the Figure 19 An enlarged cross-sectional view of the D1-D1 line. Figure 21 For the Figure 19 The enlarged cross-sectional view of the D2-D2 line. Figure 19 The cross section of the D3-D3 line shown is Figure 4 The same as above, so the illustration is omitted. Figures 19-21 The mold 3M6 shown has the same shape and structure as the manifold 32. Figure 6 The mold 3 shown is different.

[0131] Specifically, the mold 3M6 of this modification includes a manifold portion 32 connected to the resin introduction portion 31 and a connection platform portion 36 provided on the downstream side of the manifold portion 32 and connected to the manifold portion 32. Figure 6 In the example shown, the boundary BL23 between the manifold portion 32 and the connecting platform portion 33 is parallel to the X direction. Figure 19 In the case of the mold 3M6 shown, the boundary BL26 between the manifold portion 32 and the connecting platform portion 36 is not parallel to the X direction and includes portions (regions R2 and R3) inclined with respect to the X direction.

[0132] The manifold portion 32 is connected to the resin introduction portion 31 on the opposite side of the boundary BL26, and has a side 32s1 and a side 32s2 on both sides of the connection portion with the resin introduction portion. Figure 6 In the example shown, the side 32s1 and the side 32s2 are parallel to the X direction. Figure 19 In the case of the example shown, it is inclined with respect to the X direction.

[0133] In this modification, a single connection platform 36 is provided instead of a plurality of connection platforms on the downstream side of the manifold 32. An opening 25 is formed as a lip at the lower end (downstream end) of the connection platform 36.

[0134] In this modified example, the shape of the manifold portion 32 is set as described above, thereby achieving a structure that reduces the time the molten resin flows in the resin flow path portion 23. By reducing the time the molten resin flows in the resin flow path portion 23, it is possible to reduce damage to the resin caused by thermal energy.

[0135] In this modification, Figure 6The same as the mold 3 shown, in order to make the flow distribution of the molten resin in the X direction (width direction) uniform, the following conditions are required. That is, the boundary BL26 between the manifold portion 32 and the connecting platform portion 36 includes a region R1 including a portion intersecting with the central axis 32c, a region R2 located between one end of the boundary BL26 between the manifold portion 32 and the connecting platform portion 36 in the X direction and the region R1, and a region R3 located between the other end of the boundary BL26 between the manifold portion 32 and the connecting platform portion 36 in the X direction and the region R1. In the X direction, the region R1 is located at the center of the boundary BL34. Figure 6 In the example shown, in region R1 , boundary BL34 is parallel to the X direction. In other words, in region R1 , boundary BL34 is parallel to the extending direction of opening 25 .

[0136] When focusing on the inclination angles of regions R1, R2, and R3 relative to the X-direction, the following can be expressed. Specifically, in region R2, boundary BL26 is inclined at an angle less than 90 degrees with the X-direction. In region R3, boundary BL26 is inclined at an angle less than 90 degrees with the X-direction. The angle formed by boundary BL26 with the X-direction in region R1 is smaller than the angle formed by boundary BL26 with the X-direction in regions R2 and R3 (including 0 degrees).

[0137] Next, the flow path length FPL1 of the resin flow path from the boundary BL26 to the opening 25 in each of the regions R1 , R2 , and R3 will be described. Figure 19 The flow path length FPL1 shown is the flow path length of the connecting land portion 34. The flow path length FPL1 can be regarded as the dimension (length) of the connecting land portion 36 along the direction in which the molten resin flows.

[0138] In the case of this modification, in the X direction, the flow path length FPL1 is the largest (longest) in the region R1 near the center of the boundary BL26. Figure 6 In the example shown, the value of the flow path length L1 is constant regardless of the position in the X direction.

[0139] In region R2 of boundary BL26, the length of flow channel FPL1 gradually decreases from region R1 toward one end of boundary BL26. The angle between region R2 of boundary BL26 and the X-direction is constant. Therefore, if the angle between region R2 and the X-direction is defined as the rate of change of flow channel length FPL1, it can be expressed as follows. That is, in region R2, flow channel length FPL1 (flow channel length L2) gradually decreases at a first rate of change from region R1 toward one end of boundary BL26.

[0140] In region R3 of boundary BL26, the flow path length FPL1 gradually decreases from region R1 toward the other end of boundary BL26. The absolute value of the angle between region R3 of boundary BL26 and the X-direction is the same as the absolute value of the angle between region R2 of boundary BL26 and the X-direction and is constant. Therefore, if the angle between region R3 and the X-direction is defined as the rate of change of flow path length FPL1, it can be expressed as follows. That is, in region R3, flow path length FPL1 (flow path length L3) gradually decreases from region R1 toward the other end of boundary BL26 at the first rate of change described above.

[0141] However, existence and utilization Figure 14 and Figure 15 In the case of the structural combination of the mold 3M4 described above, the rate of change of the flow path length FPL1 in the region R1 changes at a rate smaller than the first rate of change.

[0142] exist Figure 19 In the case of the die 3M6 shown, the function can also be exerted to make the flow rate distribution of the molten resin in the X direction (width direction) uniform. The reason for this is as follows.

[0143] In the case of the mold 3M6, the flow path length FPL1 of the connecting platform 36 is set to be the largest in the region R1 near the center and gradually decreases from the region R1 to both ends (both ends in the X direction). Figure 21 ) is the thickness t1 of the manifold portion 32 (refer to Figure 21 ) is less than the minimum value. Therefore, the molten resin is less likely to flow in the connection platform 36 than in the manifold 32. In other words, when the molten resin flows the same distance in the manifold 32 and the connection platform 36, the flow resistance in the connection platform 36 is greater than that in the manifold 32.

[0144] By setting the flow path length FPL1 to its maximum in region R1 of boundary BL26 and gradually decreasing from region R1 toward both ends, the flow path resistance of connecting platform 36 is maximized in region R1 and gradually decreases from region R1 toward both ends (the ends in the X direction). This allows the inflow pressure of the molten resin flowing from connecting platform 36 into connecting platform 35 to be roughly consistent regardless of its position in the X direction. Specifically, considering that the inflow pressure of the molten resin flowing from manifold 32 into connecting platform 36 gradually decreases from region R1 toward both ends in the X direction, the flow path resistance of the molten resin as it passes through connecting platform 36 gradually decreases from the center toward both ends in the X direction. Accordingly, the unevenness of the inflow pressure of the molten resin when it flows from the manifold portion 32 into the connecting platform portion 36 can be offset by the unevenness of the flow path resistance of the connecting platforms 33 and 34. As a result, the unevenness of the inflow pressure of the molten resin when it flows from the connecting platform portion 36 into the connecting platform portion 35 can be suppressed, so that the flow rate of the molten resin when it is discharged from the opening portion 25 is approximately constant regardless of the position in the X direction.

[0145] use Figures 19-21 The mold 3M6 described above has the following differences: Figure 6 The mold 3 shown is the same. Therefore, regarding the structure common to the mold 3, repeated description is omitted.

[0146] In addition, it is possible to use Figures 19-21 Explanation of the structure and use of mold 3M6 Figure 10 Explanation of the structure and use of mold 3M1 Figure 11 Explanation of the structure and use of mold 3M2 Figure 12 The structure and use of the mold 3M3 described Figure 14 The structure and combination application of mold 3M4 are described.

[0147] In combining this modification with the Figure 10 Explanation of the structure and use of mold 3M1 Figure 11 Explanation of the structure and use of mold 3M2 Figure 12 The structure and use of the mold 3M3 described Figure 14 When the structure of the mold 3M4 described above is applied in combination, the boundary BL34 between the connecting platform portion 33 and the connecting platform portion 34 in each description is replaced with the boundary BL26 between the manifold portion 32 and the connecting platform portion 36.

[0148] In addition, when combining this modification with the Figure 10 The structure and use of the mold 3M1 described Figure 11 In the case of the structure combination of the mold 3M2 described above, it is preferable to satisfy the following relationship. That is, when the region overlapping the resin introduction portion 31 in the Y direction in the boundary BL26 between the manifold portion 32 and the connecting platform portion 36 is defined as region R4 (refer to Figure 10 and Figure 11 ), the width WR1 of the region R1 in the X direction is equal to the width WR4 of the region R4 (refer to Figure 10 and Figure 11 ) is 80% or more and 120% or less. Figure 10 and Figure 11 As described.

[0149] In addition, the molds of the above-mentioned modifications can be replaced with Figure 1 The mold 3 shown is applicable. For example, Figures 19-21 The mold 3M6 shown is replaced by Figure 1 In the case of the mold 3 shown, the film production apparatus 1 including the mold 3M6 and the film production method using the film production apparatus 1 can be obtained.

[0150] In summary, the invention made by the inventors has been specifically described based on the embodiments. However, the present invention is not limited to the aforementioned embodiments, and it is needless to say that various modifications are possible without departing from the scope of the present invention.

[0151] Description of Reference Numerals

[0152] 1. Film manufacturing equipment (extrusion molding equipment, extrusion molding machine)

[0153] 2 Extruder (extrusion device)

[0154] 2a Resin inlet

[0155] 3. 3C1, 3M1, 3M2, 3M3, 3M4, 3M5, 3M6 molds (extrusion molds, metal molds)

[0156] 4 cooling rollers (casting rollers)

[0157] 5 contact rollers

[0158] 6. Recovery machine (recovery device)

[0159] 7 Stretching Processor

[0160] 11 Molten resin

[0161] 11a Resin film

[0162] 111, 112 molten resin film

[0163] 21, 22 mold parts (mold body, metal mold)

[0164] 23 resin flow channel

[0165] 24 openings (supply port, introduction port)

[0166] 25 opening (discharge port)

[0167] 31 Resin inlet

[0168] 32 Manifold

[0169] 32c center axis

[0170] 32s1, 32s2 edge

[0171] 33, 34, 35, 36 connecting the platform (slit part, area) BL23, BL26, BL34, BL45 boundary BL34D imaginary line FPL1, FPL3, FPL4, FPL5, L1, L2, L3 flow path length R1, R2, area R3, R4 area W31, WR1, WR4 width

Claims

1. An extrusion die, characterized in that: include: a first opening for supplying molten resin; a second opening for discharging the molten resin; as well as a resin flow channel portion extending from the first opening portion to the second opening portion, The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; as well as a first connecting platform portion and a second connecting platform portion, which are sequentially arranged between the manifold portion and the second opening portion in a first direction from the manifold portion toward the second opening portion; The second opening extends along a second direction perpendicular to the first direction. The thickness of the second connecting platform portion is different from the thickness of the first connecting platform portion, When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the first connecting platform portion and the second connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the first connecting platform portion and the second connecting platform portion and the first region in the second direction; as well as a third region located between the first region and the other end of the boundary between the first connecting platform portion and the second connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the first connecting platform and the second connecting platform to the second opening, In the second region, the first region gradually changes from the first region side to the one end at a first change rate. In the third region, the first change rate gradually changes from the first region side to the other end. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

2. The extrusion molding die according to claim 1, wherein When a region of the boundary between the first connecting platform portion and the second connecting platform portion that overlaps with the resin introduction portion in the first direction is defined as a fourth region, In the second direction, the width of the first region is not less than 80% and not more than 120% of the width of the fourth region.

3. The extrusion molding die according to claim 1, wherein The thickness of the second connecting platform is thinner than that of the first connecting platform. Regarding the first flow channel length from the boundary between the first connecting platform and the second connecting platform to the second opening, In the second region, the first rate of change gradually decreases from the first region side to the one end portion. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. The first flow channel length in the first region is equal to or greater than the maximum value of the first flow channel length in the second region, and is equal to or greater than the maximum value of the first flow channel length in the third region.

4. The extrusion molding die according to claim 1, wherein The thickness of the second connecting platform is thicker than that of the first connecting platform. Regarding the first flow channel length from the boundary between the first connecting platform and the second connecting platform to the second opening, In the second region, the first rate of change gradually increases from the first region side to the one end portion. In the third region, the first rate of change gradually increases from the first region side to the other end portion. The first flow channel length in the first region is less than or equal to the minimum value of the first flow channel length in the second region, and is less than or equal to the minimum value of the first flow channel length in the third region.

5. The extrusion molding die according to claim 1, wherein A first flow channel length from a boundary between the first connecting platform and the second connecting platform to the second opening is constant in the first region.

6. The extrusion molding die according to claim 1, wherein A first flow channel length from a boundary between the first connecting platform and the second connecting platform to the second opening changes in the first region at a rate of change smaller than the first rate of change.

7. An extrusion molding die, characterized in that: include: a first opening for supplying molten resin; a second opening for discharging the molten resin; as well as a resin flow channel portion extending from the first opening portion to the second opening portion, The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; as well as a connecting platform portion, which is arranged between the manifold portion and the second opening portion in a manner connected to the manifold portion in a first direction, The second opening extends along a second direction perpendicular to the first direction. The thickness of the connecting platform is less than the thickness of the manifold. When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the manifold portion and the connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the manifold portion and the connecting platform portion and the first region in the second direction, and a third region located between the first region and the other end of the boundary between the manifold portion and the connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the manifold portion and the connecting platform portion to the second opening portion, In the second region, the temperature gradually decreases from the first region side to the one end at a first rate of change. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

8. The extrusion molding die according to claim 7, wherein: When a region of the boundary between the manifold portion and the connection platform portion that overlaps with the resin introduction portion in the first direction is defined as a fourth region, In the second direction, the width of the first region is not less than 80% and not more than 120% of the width of the fourth region.

9. The extrusion molding die according to claim 7, wherein: A first flow channel length from a boundary between the manifold portion and the connecting platform portion to the second opening is constant in the first region.

10. The extrusion die according to claim 7, wherein A first flow channel length from a boundary between the manifold portion and the connecting platform portion to the second opening portion changes in the first region at a rate of change smaller than the first rate of change.

11. A film manufacturing device, characterized in that: include: Extruder; a die to which the molten resin extruded from the extruder is supplied; as well as a cooling tool for cooling the molten resin discharged from the mold, The mold comprises: a first opening for supplying the molten resin; a second opening for discharging the molten resin; and a resin flow channel portion extending from the first opening portion to the second opening portion; The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; and a first connecting platform portion and a second connecting platform portion, which are sequentially arranged between the manifold portion and the second opening portion in a first direction from the manifold portion toward the second opening portion; The second opening extends along a second direction perpendicular to the first direction. The thickness of the second connecting platform portion is different from the thickness of the first connecting platform portion, When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the first connecting platform portion and the second connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the first connecting platform portion and the second connecting platform portion and the first region in the second direction; and a third region located between the first region and the other end of the boundary between the first connecting platform portion and the second connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the first connecting platform and the second connecting platform to the second opening, In the second region, the temperature gradually decreases from the first region side to the one end at a first rate of change. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

12. A film manufacturing method, characterized in that: The following steps are included: Extruding molten resin from an extruder and feeding it to a die; forming the molten resin into a film shape using the mold; as well as cooling the film-shaped molten resin discharged from the mold, The mold comprises: a first opening for supplying the molten resin; a second opening for discharging the molten resin; and a resin flow channel portion extending from the first opening portion to the second opening portion; The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; and a first connecting platform portion and a second connecting platform portion, which are sequentially arranged between the manifold portion and the second opening portion in a first direction from the manifold portion toward the second opening portion; The second opening extends along a second direction perpendicular to the first direction. The thickness of the second connecting platform portion is different from the thickness of the first connecting platform portion, When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the first connecting platform portion and the second connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the first connecting platform portion and the second connecting platform portion and the first region in the second direction; and a third region located between the first region and the other end of the boundary between the first connecting platform portion and the second connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the first connecting platform and the second connecting platform to the second opening, In the second region, the temperature gradually decreases from the first region side to the one end at a first rate of change. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

13. A film manufacturing device, characterized in that: include: Extruder; a die to which the molten resin extruded from the extruder is supplied; as well as a cooling tool for cooling the molten resin discharged from the mold, The die is an extrusion die, comprising: a first opening for supplying molten resin; a second opening for discharging the molten resin; and a resin flow channel portion extending from the first opening portion to the second opening portion; The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; and a connecting platform portion, which is arranged between the manifold portion and the second opening portion in a manner connected to the manifold portion in a first direction, The second opening extends along a second direction perpendicular to the first direction. The thickness of the connecting platform is less than the thickness of the manifold. When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the manifold portion and the connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the manifold portion and the connecting platform portion and the first region in the second direction, and a third region located between the first region and the other end of the boundary between the manifold portion and the connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the manifold portion and the connecting platform portion to the second opening portion, In the second region, the temperature gradually decreases from the first region side to the one end at a first rate of change. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

14. A film manufacturing method, characterized in that: The following steps are included: Extruding molten resin from an extruder and feeding it to a die; forming the molten resin into a film shape using the mold; as well as cooling the film-shaped molten resin discharged from the mold, The die is an extrusion die, comprising: a first opening for supplying molten resin; a second opening for discharging the molten resin; and a resin flow channel portion extending from the first opening portion to the second opening portion; The resin flow channel portion has: a resin introduction portion connected to the first opening; a manifold portion connected to the resin introduction portion; and a connecting platform portion, which is arranged between the manifold portion and the second opening portion in a manner connected to the manifold portion in a first direction, The second opening extends along a second direction perpendicular to the first direction. The thickness of the connecting platform is less than the thickness of the manifold. When an imaginary line passing through the center of the resin introduction portion and extending along the first direction to the second opening is defined as a first central axis, The boundary between the manifold portion and the connecting platform portion includes: a first region including a portion intersecting the first central axis; a second region located between one end of a boundary between the manifold portion and the connecting platform portion and the first region in the second direction, and a third region located between the first region and the other end of the boundary between the manifold portion and the connecting platform portion in the second direction; Regarding the first flow channel length from the boundary between the manifold portion and the connecting platform portion to the second opening portion, In the second region, the temperature gradually decreases from the first region side to the one end at a first rate of change. In the third region, the first rate of change gradually decreases from the first region side to the other end portion. In the first region, the value is constant or changes at a rate smaller than the first rate of change.

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