JP2023054461A - Extrusion molding mouthpiece - Google Patents

Abstract

To provide an extrusion molding mouthpiece capable of preventing exposure of side ends of a second rubber layer in a rubber ribbon.SOLUTION: An extrusion molding mouthpiece attached to an end of an extrusion molding apparatus that continuously discharges a rubber ribbon provided with a first rubber layer located on one side of a ribbon thickness direction and a second rubber layer located on the other side of the ribbon thickness direction of the first rubber layer includes: a first rubber inflow passage into which a first rubber forming the first rubber layer flows; a second rubber inflow passage extending in a direction crossing the first rubber inflow passage and into which a second rubber forming the second rubber layer flows; and a rubber ribbon discharge passage extending from a confluence position of the first rubber inflow passage and the second rubber inflow passage. The first rubber inflow passage intersects one side of the second rubber inflow passage in the ribbon thickness direction, including a side end of the second rubber inflow passage in a ribbon width direction.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to extrusion dies.

Patent Literature 1 discloses an extrusion molding device that continuously extrudes a rubber ribbon whose cross section is divided into a first rubber layer made of a first rubber and a second rubber layer made of a second rubber. In the extrusion molding device, the first rubber forming the first rubber layer and the second rubber forming the second rubber layer are combined at a rubber combining portion of the extrusion molding device to form a rubber ribbon from the die for extrusion molding. Discharge.

A rubber member is formed by spirally winding a rubber ribbon discharged from the extrusion die around a forming drum. At that time, the rubber member such as the inner liner rubber is molded so that the second rubber layer is not exposed to the molding drum side. However, if the side edges of the second rubber layer of the rubber ribbon in the ribbon width direction are exposed, the second rubber layer of the rubber member may be exposed to the forming drum side.

International Publication No. 2008/7420

An object of the present disclosure is to provide an extrusion die capable of preventing exposure of side ends of a second rubber layer in a rubber ribbon.

The extrusion molding die of the present disclosure continuously forms a rubber ribbon having a first rubber layer arranged on one side in the ribbon thickness direction and a second rubber layer arranged on the other side of the first rubber layer in the ribbon thickness direction. A die for extrusion molding attached to the tip of an extrusion molding device that discharges the material in a direction that intersects the first rubber inflow passage into which the first rubber forming the first rubber layer flows and the first rubber inflow passage. and a rubber ribbon discharge path extending from a confluence position of the first rubber inflow path and the second rubber inflow path. , the first rubber inflow path intersects one side in the ribbon thickness direction of the second rubber inflow path including the side end of the second rubber inflow path in the ribbon width direction.

A cross-sectional view of a rubber ribbon molded by an extrusion molding device according to one embodiment. Sectional drawing of the rubber ribbon shape|molded by the extrusion molding apparatus which concerns on other embodiment Sectional view showing a state in which a rubber ribbon is wound around a forming drum Schematic diagram of an extrusion molding apparatus according to one embodiment FIG. 2 is an enlarged front view of a main part of the extrusion molding device according to the same embodiment; VV line sectional view of FIG. Sectional drawing for demonstrating the molding method of the rubber ribbon in the same embodiment. Enlarged front view of essential parts of an extrusion molding device according to another embodiment VIII-VIII line sectional view of FIG.

[rubber ribbon]
First, an example of a rubber ribbon molded by an extrusion molding device will be described with reference to FIGS. 1A to 2. FIG. In each figure (FIGS. 1A to 8), the dimensional ratios of the drawings and the actual dimensional ratios do not necessarily match, and the dimensional ratios between the drawings do not necessarily match.

As shown in FIG. 1A, the rubber ribbon 100 is continuously discharged by an extrusion molding device 1, which will be described later, and molded into a long plate. The thickness of the rubber ribbon 100 gradually decreases from the center portion toward the side end portions in the ribbon width direction D2. As a result, as shown in FIG. 2, when the rubber ribbon 100 is spirally wound around the forming drum 400, the thickness of the rubber member 500 formed by the rubber ribbon 100 can be made nearly uniform. In this embodiment, the rubber ribbon 100 is shaped to have a substantially triangular cross-section, but is not limited to this. For example, the rubber ribbon 100 may be shaped to have a substantially trapezoidal cross section, a substantially crescent cross section, or the like.

As shown in FIG. 1A, the rubber ribbon 100 includes a first rubber layer 101 arranged on one side in the ribbon thickness direction D1 (first ribbon thickness direction D11), and the other side of the first rubber layer 101 in the ribbon thickness direction D1. and a second rubber layer 102 arranged in the (second ribbon thickness direction D12). In this embodiment, one side in the ribbon thickness direction D1 corresponds to the inner side in the tire radial direction, and the other side in the ribbon thickness direction D1 corresponds to the outer side in the tire radial direction.

Side ends 102a, 102a of the second rubber layer 102 in the ribbon width direction D2 are covered with the first rubber layer 101. As shown in FIG. Thereby, as shown in FIG. 2, when the rubber ribbon 100 is spirally wound around the forming drum 400, the second rubber layer 102 can be prevented from being exposed to the forming drum 400 side. The second rubber layer 102 is exposed at the central portion of the rubber ribbon 100 in the ribbon width direction D2. In this embodiment, as shown in FIG. 1A, the first rubber layer 101 covers the second rubber layer 102 from the side ends 102a, 102a of the second rubber layer 102 to the second ribbon thickness direction D12 side. , but not limited to this. For example, as shown in FIG. 1B, the first rubber layer 101 may cover the side ends 102a of the second rubber layer 102 up to 102a.

As shown in FIG. 2, the rubber member 500 is molded by spirally winding the rubber ribbon 100 around the molding drum 400 . By molding the rubber member 500 using the rubber ribbon 100 in which the rubber layers 101 and 102 are integrated, the molding time of the rubber member 500 can be shortened and the number of sheets can be reduced as compared with the case where the rubber layers 101 and 102 are wound separately. It is possible to reduce mistakes in attaching the first rubber layer 101 and the second rubber layer 102 . In addition, it becomes easy to adjust the ratio of each rubber layer 101, 102 in the rubber member 500, and for example, it is possible to reduce the weight of a pneumatic tire (hereinafter simply referred to as "tire") and improve tire performance such as rolling resistance. .

In this embodiment, the rubber member 500 is inner liner rubber of a tire, but is not limited to this. The first rubber layer 101 forms the innermost surface of the tire. The second rubber layer 102 is arranged between the first rubber layer 101 and a carcass ply arranged outside the inner liner rubber in the tire radial direction.

The first rubber layer 101 is made of a first rubber, and the second rubber layer 102 is made of a second rubber different from the first rubber. In the present embodiment, the first rubber is butyl rubber which is excellent in preventing air permeation. The second rubber is a squeegee rubber that prevents the carcass ply from being exposed on the innermost surface of the tire when the unvulcanized tire is expanded by the bladder. Squeegee rubber is a rubber material harder than butyl rubber. In addition, the first rubber and the second rubber are not limited to the above.

When the side ends 102a, 102a of the second rubber layer 102 in the rubber ribbon 100 are exposed, the second rubber layer 102 is exposed on the tire innermost surface of the inner liner rubber (the molding drum 400 side of the rubber member 500), Air in the tire may permeate through the exposed portion of the two rubber layers 102 . Therefore, it is necessary to suppress the exposure of the second rubber layer 102 on the tire innermost surface of the inner liner rubber by suppressing the exposure of the side ends 102a, 102a of the second rubber layer 102 in the rubber ribbon 100. FIG.

[Extrusion device]
Next, an example of an extrusion molding apparatus will be described with reference to FIGS. 3 to 5. FIG.

As shown in FIG. 3, the extrusion molding device 1 includes a first rubber extruder 8 that extrudes the first rubber, a first rubber supply section 2 that supplies the first rubber, and a second rubber extruder that extrudes the second rubber. 9, a second rubber supply unit 3 that supplies the second rubber, and an extrusion die (hereinafter simply referred to as " ) 4, which is referred to as a "base".

The rubber ribbon 100 ejected from the die 4 is conveyed by a plurality of conveying rollers 200 and pressed against the forming drum 400 by the pressing roller 300 . The forming drum 400 is configured to be movable in its axial direction (the direction perpendicular to the plane of FIG. 3) and to be rotatable around its axis. The rubber ribbon 100 is helically wound around the forming drum 400 by moving the forming drum 400 into which the rubber ribbon 100 is fed while rotating in the axial direction.

The first rubber supply section 2 is attached to the first rubber extruder 8 . As shown in FIGS. 3 and 5 , the first rubber supply section 2 includes a first rubber supply path 21 that supplies the first rubber extruded from the first rubber extruder 8 to the mouthpiece 4 . In the present embodiment, the first rubber supply path 21 has a substantially circular cross section and is arranged on the first ribbon thickness direction D11 side of the mouthpiece 4, but is not limited to this. In this embodiment, the first rubber supply section 2 is separate from the second rubber supply section 3 , but may be integrated with the second rubber supply section 3 .

As shown in FIG. 3 , the second rubber feeder 3 is attached to the second rubber extruder 9 . As shown in FIGS. 3 and 5 , the second rubber supply section 3 includes a second rubber supply passage 31 that supplies the second rubber extruded from the second rubber extruder 9 to the mouthpiece 4 . In the present embodiment, the second rubber supply path 31 is formed to have a substantially circular cross section, but it is not limited to this. The second rubber supply path 31 is arranged on the upstream side of the nozzle 4 in the ribbon discharge direction D3.

[Extrusion die]
As shown in FIGS. 4 and 5, the die 4 is arranged at the tip of the extrusion molding device 1 and attached to the first rubber supply section 2 and the second rubber supply section 3 (for example, bolted). In this embodiment, the base 4 is formed in a substantially rectangular parallelepiped shape, but it is not limited to this. The base 4 includes a first base 5 arranged on the downstream side in the ribbon discharge direction D3 and a second base 6 arranged on the upstream side in the ribbon discharge direction D3. In this embodiment, the first base 5 and the second base 6 are separate bodies, and fixed to the first rubber supply section 2 and the second rubber supply section 3 by a fixing member (for example, bolt fastening) not shown. ing. Note that the first cap 5 may be formed integrally with the second cap 6 .

The mouthpiece 4 includes a first rubber inflow passage 41 into which the first rubber flows, a second rubber inflow passage 42 into which the second rubber flows, and a rubber ribbon 100 formed by forming the first rubber and the second rubber into a ribbon discharge direction D3. and a rubber ribbon discharge path 43 for discharging the rubber ribbon.

The second rubber inflow path 42 extends from the second rubber supply path 31 to the rubber ribbon discharge path 43 . In this embodiment, the second rubber inflow path 42 is a through hole that penetrates the second mouthpiece 6 . The second rubber inflow path 42 is formed in a substantially triangular shape when viewed in the ribbon discharge direction D3. In addition, the second rubber inflow path 42 is not limited to the above.

The second rubber inflow path 42 extends in a direction crossing the first rubber inflow path 41 . In the present embodiment, the second rubber inflow path 42 extends in the same direction as the rubber ribbon discharge path 43 (ribbon discharge direction D3), but it is not limited to this. For example, the second rubber inflow path 42 may extend in a direction crossing the rubber ribbon discharge path 43 . The second rubber inflow path 42 preferably extends in the same direction as the second rubber supply path 31 from the viewpoint of improving the rubber flow of the second rubber.

In the present embodiment, the thickness T2 of the second rubber inflow passage 42 is constant, but is not limited to this. For example, the thickness T2 may decrease toward the joining position P1 where the first rubber inflow passage 41 and the second rubber inflow passage 42 join. Also, the width W2 of the second rubber inflow path 42 in the ribbon width direction D2 is constant, but is not limited to this. For example, the width W2 may narrow toward the confluence position P1.

The confluence position P1 is a position on the upstream side in the ribbon discharging direction D3 where the first rubber inflow path 41 and the second rubber inflow path 42 merge. In this embodiment, the confluence position P1 is located on the upstream end face 51 of the first mouthpiece 5 (the downstream end face 61 of the second mouthpiece 6).

The first rubber inflow path 41 extends from the first rubber supply path 21 to the rubber ribbon discharge path 43 . In the present embodiment, the first rubber inflow path 41 is formed by the first mouthpiece 5 and the second mouthpiece 6, but is not limited to this.

The first nozzle 5 has a concave portion 51a on the upstream end face 51 in the ribbon discharge direction D3. The concave portion 51a extends from a position where it intersects the rubber ribbon discharge path 43 to an end surface 53 of the first nozzle 5 in the first ribbon thickness direction D11. By attaching the first nozzle 5 to the second nozzle 6, the recess 51a and the downstream end surface 61 of the second nozzle 6 in the ribbon discharging direction D3 form the first rubber inflow path 41. As shown in FIG.

According to such a configuration, the shape of the first rubber inflow passage 41 can be easily changed by changing the shape of the recess 51a. That is, the shape of the first rubber inflow passage 41 can be easily changed by replacing the first mouthpiece 5 having a different shape of the concave portion 51a.

The first rubber inflow passage 41 may be, for example, a hole extending inward from the outside of the first mouthpiece 5 , and includes a through hole penetrating the second mouthpiece 6 and an inner side of the first mouthpiece 5 from the through hole. It may be a hole configured with an extending hole.

The first rubber inflow path 41 preferably extends in the same direction as the first rubber supply path 21 from the viewpoint of improving the rubber flow of the first rubber. The confluence angle of the first rubber inflow passage 41 and the second rubber inflow passage 42 is preferably 90 degrees or less from the viewpoint of improving the confluence of the first rubber and the second rubber. The confluence angle is the angle between the center line of the first rubber inflow passage 41 and the center line of the second rubber inflow passage 42 .

In this embodiment, the first rubber inflow passage 41 is formed in a flat plate shape. That is, the thickness T1 of the first rubber inflow passage 41 is constant. The thickness T1 may decrease toward the confluence position P1. That is, the junction position side thickness T11 of the thickness T1 may be smaller than the supply path side thickness T12 of the thickness T1.

The first rubber inflow path 41 extends along one side of the second rubber inflow path 42 in the ribbon thickness direction D1 (first ribbon thickness direction D11) including the side ends 421, 421 of the second rubber inflow path 42 in the ribbon width direction D2. intersect with From the viewpoint of reliably covering the side ends 102a, 102a of the second rubber layer 102 in FIG. It is preferable to cross 50% or more of the thickness in the ribbon thickness direction D1 up to the central portion 422 . The first rubber inflow path 41 may cover the entire circumference of the second rubber inflow path 42 .

A width W1 of the first rubber inflow path 41 in the ribbon width direction D2 is larger than a width W2 of the second rubber inflow path 42 . From the viewpoint of improving the flow of rubber to the downstream side of the first rubber inflow passage 41, it is preferable that the width W1 is narrowed toward the confluence position P1. In the present embodiment, the downstream end portions 411, 411 of the first rubber inflow passage 41 are formed in an arc shape, but the shape is not limited to this.

From the viewpoint of improving the rubber flow of the first rubber to the downstream end portions 411, 411, the first rubber inflow passage 41 has a shape in which the thickness T1 at the central portion in the ribbon width direction D2 is reduced, or may be formed in a shape in which the thickness T1 of the side end portion of is greatly widened.

The rubber ribbon discharge path 43 extends outward from the mouthpiece 4 from the confluence position P1. In this embodiment, the rubber ribbon discharge path 43 is a through hole that penetrates the first mouthpiece 5 . Although the rubber ribbon discharge path 43 is formed in a substantially triangular shape when viewed in the ribbon discharge direction D3, it is not limited thereto.

The area of the cross section perpendicular to the rubber ribbon discharge path 43 is preferably larger than the area of the cross section perpendicular to the second rubber inflow path 42 . In the present embodiment, the thickness T3 of the rubber ribbon discharge path 43 in the ribbon thickness direction D1 is greater than the thickness T2 of the second rubber inflow path 42, and the width W3 of the rubber ribbon discharge path 43 in the ribbon width direction D2 is equal to the thickness of the second rubber inflow path. greater than the width W2 of the path 42;

The thickness T1 of the first rubber inflow path 41 at the confluence position P1 (the thickness T11 on the confluence position side) is preferably smaller than the thickness T3 of the rubber ribbon discharge path 43 . The width W3 should be 90% to 110% of the width W1 of the first rubber inflow passage 41 from the viewpoint of reliably covering the side ends 102a, 102a of the second rubber layer 102 in FIG. 1A with the first rubber layer 101. is preferred.

The rubber ribbon discharge path 43 has a discharge port 43a through which the rubber ribbon 100 is discharged. The discharge port 43a is arranged on the downstream end face 52 of the first nozzle 5 in the ribbon discharge direction D3. A minimum length Lmin from the first rubber inflow passage 41 to the discharge port 43a is preferably 2 mm or more. From the viewpoint of preventing deformation of the rubber ribbon 100 due to contact with the rubber ribbon discharge path 43, the length Lmax of the rubber ribbon discharge path 43 (from the confluence position P1 to the discharge port 43a) is 10 times or less the thickness T3 of the rubber ribbon discharge path 43. It is preferable that the thickness be equal to or less than the thickness T3, and it is more preferable that the thickness be 5 times or less of the thickness T3.

The thicknesses of the first rubber layer 101 and the second rubber layer 102 in FIG. It is appropriately set depending on the inflow speed, the inflow speed of the second rubber, and the like.

[Rubber ribbon molding method]
Next, an example of a molding method of the rubber ribbon 100 using the extrusion molding device 1 will be described with reference to FIG.

First, as shown in FIG. 6(a), the second rubber R2 is supplied from the second rubber supply passage 31 by attaching the second mouthpiece 6 to the second rubber supply portion 3, and the second rubber R2 is supplied to the second rubber inflow passage 42. 2 Fill with rubber R2. Then, the supply of the second rubber R2 is stopped, and the second rubber R2 protruding outside the second rubber inflow passage 42 (second mouthpiece 6) is removed.

Next, as shown in FIG. 6B, the first mouthpiece 5 is attached to the second mouthpiece 6, and the first rubber supply part 2 is attached to the first mouthpiece 5 and the second mouthpiece 6. Next, as shown in FIG. Then, the first rubber R1 is supplied from the first rubber supply path 21 to fill the first rubber inflow path 41 and the rubber ribbon discharge path 43 with the first rubber R1.

Next, as shown in FIG. 6C, after stopping the supply of the first rubber R1, the second rubber R2 is supplied again to fill the rubber ribbon discharge path 43 with the second rubber R2. At this time, the first rubber R1 filled in the rubber ribbon discharge path 43 is pushed out of the rubber ribbon discharge path 43 (first mouthpiece 5) by the second rubber R2, and the rubber ribbon discharge path 43 is discharged from the first rubber inflow path 41. Only a part of the first rubber R1 protruded to the outside remains in the rubber ribbon discharge path 43.

Then, by stopping the supply of the second rubber R2, the preparation for molding the rubber ribbon 100 is completed. By making preparations for molding, it is possible to prevent the second rubber R2 from flowing into the first rubber inflow passage 41 . In addition, even if the rubbers R1 and R2 are of the same color, it is possible to reliably confirm whether the rubbers R1 and R2 have been discharged from the mouthpiece 4 or not. It should be noted that the preparation for molding is preferably performed at the time of mounting the die 4 or after maintenance of the extrusion molding apparatus 1 .

After the preparation for molding is completed, as shown in FIG. The second rubber R2 flowing from the inflow path 42 merges at the merging position P1 to form the rubber ribbon 100, and the rubber ribbon 100 is discharged from the discharge port 43a.

As described above, as in the present embodiment, the extrusion die 4 is arranged on one side (the first ribbon thickness direction D11) of the ribbon thickness direction D1, and the first rubber layer 101 is arranged on the ribbon thickness direction. An extrusion die 4 attached to the tip of an extrusion molding device 1 that continuously discharges a rubber ribbon 100 having a second rubber layer 102 arranged on the other side of D1 (second ribbon thickness direction D12), A first rubber inflow passage 41 into which the first rubber R1 forming the first rubber layer 101 flows, and a second rubber R2 extending in a direction intersecting the first rubber inflow passage 41 and forming the second rubber layer 102 flows in. A second rubber inflow path 42 and a rubber ribbon discharge path 43 extending from a confluence position P1 of the first rubber inflow path 41 and the second rubber inflow path 42 are provided. It is preferable that the second rubber inflow path 42 including the side ends 421, 421 of 42 in the ribbon width direction D2 intersects one side (the first ribbon thickness direction D11) in the ribbon thickness direction D1.

According to such a configuration, the side end portion in the ribbon width direction D2 of the second rubber R2 flowing in from the second rubber inflow path 42 can be covered with the first rubber R1 flowing in from the first rubber inflow path 41 . As a result, the side ends 102a, 102a of the second rubber layer 102 can be covered with the first rubber layer 101, and the side ends 102a, 102a of the second rubber layer 102 of the rubber ribbon 100 can be prevented from being exposed. .

Further, like the extrusion die 4 according to the present embodiment, it is preferable that the area of the cross section orthogonal to the rubber ribbon discharge path 43 is larger than the area of the cross section orthogonal to the second rubber inflow path 42 .

According to such a configuration, it is possible to secure a space for joining the first rubber R1 and the second rubber R2 in the rubber ribbon discharge path 43, and the first rubber layer 101 is arranged at the side ends 102a and 102a of the second rubber layer 102. The rubber ribbon 100 can be molded while keeping the state of covering 102a.

Further, like the extrusion die 4 according to this embodiment, the thickness T1 of the first rubber inflow path 41 at the confluence position P1 (the thickness T11 on the confluence position side) is equal to the thickness T3 of the rubber ribbon discharge path 43 in the ribbon thickness direction D1. is preferably smaller than .

Such a configuration makes it easier for the second rubber R2 to flow into the rubber ribbon discharge passage 43, thereby suppressing the second rubber R2 from flowing into the first rubber inflow passage 41. As shown in FIG.

Further, like the extrusion die 4 according to this embodiment, it is preferable that the minimum length Lmin from the first rubber inflow passage 41 to the discharge port 43a of the rubber ribbon discharge passage 43 is 2 mm or more.

According to such a configuration, it is possible to stabilize the flow of rubber after the first rubber R1 and the second rubber R2 join together, and the first rubber layer 101 moves the side ends 102a, 102a of the second rubber layer 102. The rubber ribbon 100 can be molded while maintaining the covered state.

The extrusion die 4 is not limited to the configuration of the embodiment described above, nor is it limited to the effects described above. Further, the extrusion die 4 can of course be modified in various ways without departing from the gist of the present invention. For example, it is of course possible to arbitrarily select one or a plurality of configurations, methods, etc., according to various modified examples described below, and employ them in the configurations, methods, etc., according to the above-described embodiment.

As shown in FIGS. 7 and 8, the extrusion molding die 4 may be configured to include a rubber flow adjusting portion 7 for adjusting the rubber flow of the first rubber. According to such a configuration, the rubber flow adjusting section 7 can adjust the rubber flow of the first rubber in response to changes in the rubber flow of the first rubber due to variations in the molding environment of the rubber ribbon 100 and the viscosity of the first rubber. can. In addition, the extrusion die 4 may be provided with a plurality of rubber flow adjusting portions 7 .

From the viewpoint of improving the rubber flow of the first rubber to the downstream end portions 411, 411 of the first rubber inflow passage 41, the rubber flow adjusting portion 7 is arranged in the center of the first rubber inflow passage 41 in the ribbon width direction D2. is preferably arranged. As the rubber flow adjusting portion 7, for example, a male screw such as a bolt can be used. In the case of a male screw, it is necessary to provide the first cap 5 or the second cap 6 with a female thread penetrating to the first rubber inflow passage 41 . By rotating the male screw, it is possible to adjust the passage length T4 of the male screw entering the first rubber inflow passage 41, thereby adjusting the rubber flow of the first rubber.

DESCRIPTION OF SYMBOLS 1... Extrusion apparatus, 2... 1st rubber supply part, 21... 1st rubber supply path, 3... 2nd rubber supply part, 31... 2nd rubber supply path, 4... Die for extrusion molding, 41... 1st rubber Inflow path 411 Downstream side end 42 Second rubber inflow path 421 Side end 422 Center part 43 Rubber ribbon discharge path 43a Discharge port 5 First mouthpiece 51a Concave portion 6... Second nozzle, 7... Adjusting unit, 8... First rubber extruder, 9... Second rubber extruder, 100... Rubber ribbon, 101... First rubber layer, 102... Second rubber layer, 102a... Side end , 200 Conveying roller 300 Pressing roller 400 Forming drum 500 Rubber member P1 Merging position R1 First rubber R2 Second rubber T4 Flow passage penetration length

Claims (4)

A tip end of an extruder for continuously discharging a rubber ribbon comprising a first rubber layer arranged on one side in the ribbon thickness direction and a second rubber layer arranged on the other side of the first rubber layer in the ribbon thickness direction. An extrusion die attached to the
a first rubber inflow path into which the first rubber forming the first rubber layer flows;
a second rubber inflow path extending in a direction crossing the first rubber inflow path and into which the second rubber forming the second rubber layer flows;
a rubber ribbon discharge path extending from a confluence position of the first rubber inflow path and the second rubber inflow path;
The extrusion molding die, wherein the first rubber inflow path intersects one side of the second rubber inflow path in the ribbon thickness direction including the side end of the second rubber inflow path in the ribbon width direction. 2. The die for extrusion molding according to claim 1, wherein the area of the cross section orthogonal to said rubber ribbon discharge path is larger than the area of the cross section orthogonal to said second rubber inflow path. 3. The die for extrusion molding according to claim 1, wherein the thickness of said first rubber inflow path at said joining position is smaller than the thickness of said rubber ribbon discharge path in the ribbon thickness direction. The die for extrusion molding according to any one of claims 1 to 3, wherein a minimum length from said first rubber inflow passage to an outlet of said rubber ribbon discharge passage is 2 mm or more.

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