JP6862746B2 - Manufacturing method of extruded rubber - Google Patents

Description

The present invention relates to a method for producing a rubber extruded product. More specifically, when a plurality of unrefined rubbers are extruded from one extrusion port and integrated, the extruded rubber is extruded while suppressing fluctuations in the interface between the rubbers. The present invention relates to a method for producing an extruded rubber product capable of suppressing bending of an object.

When manufacturing rubber products such as tires, there is an extrusion process in which unvulcanized rubber is extruded by a rubber extruder. In a rubber extruder, so-called multicolor rubber extrusion, in which a plurality of unvulcanized rubbers are extruded from one extrusion port and integrated, may be performed (see, for example, Patent Document 1).

In multicolor rubber extrusion, due to the difference in flow velocity immediately before the extrusion port of each unvulcanized rubber that is sent out, each unvulcanized rubber is integrated and the rubber extrusion extruded from the extrusion port is curved. There is. In order to suppress the curvature of this rubber extrusion, the rotation speed (extrusion speed) of the screw that feeds out the unvulcanized rubber is adjusted to reduce the flow velocity difference between the unvulcanized rubbers. The interface between them fluctuates. As a result, the shape of the extruded rubber may not be obtained as set.

Japanese Unexamined Patent Publication No. 2015-47838

An object of the present invention is a rubber capable of suppressing bending of an extruded rubber extruded product while suppressing fluctuations in the interface between rubbers when a plurality of unvulcanized rubbers are extruded from one extrusion port and integrated. The purpose is to provide a method for producing an extruded product.

In order to achieve the above object, in the method for producing a rubber extruded product of the present invention, a plurality of unvulcanized rubbers are flowed through a flow path formed in one die and extruded from one extrusion port at the end of the flow path. the method of manufacturing a rubber extrudate to produce an integrated allowed rubber extrudate to the die, extruded a constant thickness flat plate-shaped rectifying plates rigid to fully isolate each of the unvulcanized rubber together The vulcanizing plate is extended and fixed in the direction, the extending length of the vulcanizing plate is set to 10 mm or more, the front end of the vulcanizing plate is set to a position recessed by 1 mm or more from the front end surface of the extrusion port, and each of the above By adjusting the flow velocity of at least one unvulcanized rubber in the die among the unvulcanized rubbers, the flow velocity of each of the unvulcanized rubbers in the die is set to be about the same, and the flow velocity of each of the unvulcanized rubbers is set to the same level. In the region where the rectifying plate exists, the unvulcanized rubbers are completely separated from each other, and the flow path is partitioned by the rectifying plate and flowed into a compartmentalized flow path having a different cross-sectional area. A method for producing a rubber extruded product, which comprises guiding the unvulcanized rubber forward in a region in front of the rectifying plate to integrate the unvulcanized rubber.

According to the present invention, a rigid rectifying plate that completely separates each unvulcanized rubber from each other is extended and fixed in the extrusion direction to one die on which one extrusion port is formed, and the rectification is performed. The front end of the plate is set at a position recessed by 1 mm or more from the front end surface of the extrusion port. As a result, in the region where the straightening vane of the die exists, the unvulcanized rubbers can be guided forward in a state of being completely separated from each other. Therefore, the facing surfaces of the unvulcanized rubbers are in a constant state along the straightening vane until just before joining each other. Along with this, even if the flow velocity of each unvulcanized rubber is adjusted to the same extent, it is possible to suppress the fluctuation of the boundary surface of each unvulcanized rubber when it becomes an integrated rubber extrusion. Further, by adjusting the flow velocity of each unvulcanized rubber to the same extent, it is possible to avoid a problem that the integrated rubber extrusion is curved. Further, by setting the front end of the straightening vane at a position recessed by 1 mm or more from the front end surface of the extrusion port, it is possible to firmly integrate the unvulcanized rubbers in the region in front of the straightening vane. it can.

It is explanatory drawing which illustrates the cross-sectional structure of the rubber extruder used in this invention in the side view. It is explanatory drawing which illustrates the die of FIG. 1 in the front view. It is an enlarged view around the die and the head of FIG. It is explanatory drawing which illustrates the state in which each unvulcanized rubber is integrated by the rubber extruder of FIG. It is explanatory drawing which illustrates the deformation example of a straightening vane in a vertical cross-sectional view.

Hereinafter, the method for producing an extruded rubber product of the present invention will be described based on the embodiment shown in the figure.

The rubber extrusion manufacturing apparatus 1 used in the present invention illustrated in FIGS. 1 to 3 includes a plurality of tubular cylinders 2A and 2B, and one head 4 installed at the tips of the plurality of cylinders 2A and 2B. This is a so-called multicolor rubber extruder provided with a die 5 having one extrusion port 6 arranged at the tip of the one head 4. The cylinders 2A and 2B are internally provided with screws 3A and 3B for supplying the internally kneaded unvulcanized rubbers r1 and r2 toward the head 4. A rigid straightening vane 8 is further installed on the die 5 in the manufacturing apparatus 1. A take-up conveyor 9 is arranged in front of the extrusion port 6.

A plurality of unvulcanized rubbers r1 and r2 supplied from the cylinders 2A and 2B by the rotating screws 3A and 3B are extruded from one extrusion port 6 to form an integrated rubber extrusion R. While being extruded from the extrusion port 6, the rubber extruded product R is taken up by the take-up conveyor 9 and conveyed to the next process.

The straightening vane 8 is arranged in the vicinity of the extrusion port 6, extends in the extrusion direction of the rubber extrusion R, and is fixed to the die 5. The rectifying plate 8 is a rigid body that completely separates the unvulcanized rubbers r1 and r2 supplied from the cylinders 2A and 2B from each other, and is made of a metal such as a steel plate.

The front end 8a of the straightening vane 8 is set at a position recessed by 1 mm or more from the front end surface of the extrusion port 6. That is, a straightening vane 8 having an extending length b extending rearward from the position of the predetermined dimension a starting from the position of the predetermined dimension a is installed behind the front end surface of the extrusion port 6, and the predetermined dimension a is set to 1 mm or more. There is. Due to the presence of the straightening vane 8, the die 5 is formed with a first flow path 7A through which one unvulcanized rubber r1 flows and a second flow path 7B through which the other unvulcanized rubber r2 flows.

The upper limit of the predetermined dimension a is set in the range where the straightening vane 8 is in the vicinity of the extrusion port 6, and is, for example, about 30 mm. The extending length b is set to, for example, 10 mm or more. The upper limit of the extended length b is, for example, about 100 mm, but is not limited to this.

The thickness of the straightening vane 8 is set to 0.5 mm or more so as not to be easily deformed by the pressure of the flowing unvulcanized rubbers r1 and r2. In order to surely suppress the deformation of the straightening vane 8, this thickness is preferably 2 mm or more. On the other hand, if the thickness of the straightening vane 8 is excessive, it becomes difficult to integrate the unvulcanized rubbers r1 and r2, so the thickness is set to 3 mm or less, for example.

In this embodiment, the upper portion of the straightening vane 8 of the extrusion port 6 is smaller than the lower portion of the straightening vane 8 and is unevenly distributed on one side in the width direction. The opening shape of the extrusion port 6 is not limited to the shape shown in this embodiment, and other shapes are also adopted. For example, the upper portion and the lower portion of the straightening vane 8 of the extrusion port 6 may have the same shape. Further, the specification is not limited to the specification in which the two cylinders 2A and 2B are provided as in this embodiment, and three or more cylinders may be provided. Even in that case, the arrangement and specifications of the straightening vane 8 are as described above.

Next, a procedure for producing the rubber extruded product R by using the method for producing the rubber extruded product of the present invention will be described.

In order to extrude the rubber extrusion R by the rubber extruder 1, a predetermined amount of unvulcanized raw rubber and a compounding agent are charged into the cylinders 2A and 2B, respectively. The charged material is mixed and kneaded by rotating screws 3A and 3B. The mixed and kneaded unvulcanized rubbers r1 and r2 are softened to some extent (plasticized) and molded into the cross-sectional shape of the extrusion port 6 to form the unvulcanized rubber extrusion R. It is extruded into a sheet. The unvulcanized rubbers r1 and r2 may be of the same type (same rubber physical characteristics) or different types (different rubber physical characteristics).

At this time, the unvulcanized rubbers r1 and r2 sent forward by the screws 3A and 3B are attached to one head 4 and one head 4 and a die 5 as illustrated in FIG. Is aggregated in. In the region where the straightening vane 8 of the die 5 exists, the unvulcanized rubbers r1 and r2 are guided forward in a state of being completely separated from each other by the straightening vane 8. Therefore, the opposing surfaces of the unvulcanized rubbers r1 and r2 flow along the straightening vane 8 until just before they are joined to each other, so that they are formed in a certain state.

The unvulcanized rubbers r1 and r2 are naturally bonded to each other and integrated in the extruded flow in the region in front of the straightening vane 8. That is, due to the swells (property to spread) of the unvulcanized rubbers r1 and r2 completely separated by the straightening vane 8, the facing surfaces of the rubber extruded products R are automatically joined to each other in the region in front of the straightening vane 8. To do.

When the flow velocity difference between the dies 5 of the unvulcanized rubbers r1 and r2 is large, the flow velocities of at least one of the unvulcanized rubbers R1 (r2) are adjusted so that the respective flow velocities are the same (for example, the flow velocities are the same or The flow velocity difference of each flow velocity should be within 3%). Even if the flow rates of the unvulcanized rubbers r1 and r2 are adjusted in this way, when the two are joined, their facing surfaces are in a constant state along the rectifying plate 8, so that the rubber extruded product is integrated. It is possible to suppress the fluctuation of the boundary surface M (opposing surface) of the unvulcanized rubbers r1 and r2 when the value becomes R. When the difference in flow velocity between the dies 5 of the unvulcanized rubbers r1 and r2 is small, it is not necessary to adjust the flow velocity of the unvulcanized rubbers r1 and r2.

Then, by making the flow velocities of the unvulcanized rubbers r1 and r2 about the same, it is possible to avoid a problem that the integrated rubber extruded product R is curved. That is, it is possible to suppress the curvature of the rubber extruded product R generated due to the difference in the flow velocities of the unvulcanized rubbers r1 and r2, respectively. Further, by setting the front end 8a of the straightening vane 8 at a position retracted by 1 mm or more from the front end surface of the extrusion port 6, the unvulcanized rubbers r1 and r2 are separated from each other in the region in front of the straightening vane 8. It can be firmly integrated without being left alone.

If the predetermined dimension a is less than 1 mm, the rubber extruded product R is more likely to remain separated by the straightening vane 8, which hinders its use in the subsequent process. Therefore, in the present invention, by setting the predetermined dimension a to 1 mm or more, the facing surfaces of the unvulcanized rubbers r1 and r2 can be easily joined to each other. When the facing surfaces are joined to each other, the facing surfaces disappear and become a close contact boundary surface M, which is conveyed to the next process by the take-up conveyor 9. Therefore, the extruded rubber R can be directly sent to the next process of the production line for use. If the predetermined dimension a is made excessive, the effect of suppressing the fluctuation of the boundary surface M of the unvulcanized rubbers r1 and r2 is lost. Therefore, the predetermined dimension a is preferably 1 mm or more and 30 mm or less, for example.

When the extending length b of the straightening vane 8 is set to 10 mm or more, the unvulcanized rubbers r1 and r2 in contact with the surface of the straightening vane 8 can be sufficiently leveled. Therefore, it is advantageous to suppress the fluctuation of the boundary surface M of the rubber extruded product R. The appropriate extension length b is, for example, 10 mm or more and 70 mm or less.

The front end portion of the straightening vane 8 is not limited to the shape illustrated in this embodiment, and other shapes can be adopted. One surface of the front end portion may be an inclined surface as illustrated in FIG. 5 (A), or both sides of the front end portion may be an inclined surface as illustrated in FIG. 5 (B). As illustrated in FIGS. 5A and 5B, if the front end portion of the straightening vane 8 has a shape that becomes thinner toward the front, the unvulcanized rubbers r1 and r2 can be easily integrated.

1 Extruder 2A, 2B Cylinder 3A, 3B Screw 4 Head 5 Die 6 Extrusion port 7A First flow path 7B Second flow path 8 Rectifier plate 8a Front end 9 Take-up conveyor r1, r2 Unvulcanized rubber R Rubber extrusion M Boundary surface

Claims (5)

In a method for producing a rubber extruded product, which produces a rubber extruded product in which a plurality of unvulcanized rubbers are flowed through a flow path formed in one die and extruded from one extrusion port at the end of the flow path to be integrated. ,
The die, and fixed constant thickness flat plate-shaped rectifying plates rigid to fully isolate each of the unvulcanized rubber together extend in the extrusion direction, the extending length of the current plate Set to 10 mm or more, set the front end of the rectifying plate to a position recessed by 1 mm or more from the front end surface of the extrusion port, and use the die of at least one unvulcanized rubber among the unvulcanized rubbers. By adjusting the flow velocity of each of the unvulcanized rubbers, the flow velocity of each of the unvulcanized rubbers in the die is set to be about the same, and in the region where the rectifying plate of the die exists, each of the unvulcanized rubbers is used. In a state of being completely separated from each other , the flow paths are divided by the vulcanizing plate and formed by partitioning the flow paths into compartmentalized flow paths having different cross-sectional areas to guide the flow forward, and in the region in front of the rectifying plate, each of them. A method for producing an extruded rubber, which comprises integrating the unvulcanized rubber. The method for producing a rubber extruded product according to claim 1, wherein the front end of the straightening vane is set within a range of 30 mm or less rearward from the front end surface of the extrusion port. The method for producing a rubber extruded product according to claim 1 or 2, wherein the thickness of the flow path is constant, and the straightening vane is arranged parallel to the flow path in a side view . The method for producing an extruded rubber product according to any one of claims 1 to 3, wherein the thickness of the straightening vane is 0.5 mm or more and 3 mm or less . The method for producing an extruded rubber according to any one of claims 1 to 4, wherein the straightening vane has a shape in which only the front end portion thereof becomes thinner toward the front .

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