JP2019077087A - Warming extruder, rubber extrusion apparatus and rubber extrusion method - Google Patents

Abstract

An object of the present invention is to prevent the rubber composition from staying in a rubber flow path for a long time and to prevent the occurrence of rubber burn even in a rubber member containing a high ratio of insoluble sulfur such as a P / F strip. A hot-extrusion technique that can be appropriately heated and extruded without inviting. A screw is housed therein, and a cylinder for feeding the injected rubber composition while heating the rubber composition to a downstream extrusion head by rotation of the screw, and a rubber composition sent out are provided at a front end portion. A hot extruder equipped with an extrusion head for extruding from an opening of a base, wherein the opening of the base has an opening width of 80 to 100% of the cylinder diameter and an opening gauge of 1.0 to 3.5 mm. , A hot extruder that is shaped like a letter. [Selection diagram] FIG.

Description

  The present invention relates to the hot extrusion technique performed in the production of a rubber strip which is a rubber material for a tire.

  In the manufacture of pneumatic tires, various rubber members such as tread rubber, sidewall rubber, inner liner rubber and the like are used because the required characteristics at each portion are different, and in recent years, strip-like rubber strips are continuously formed on a forming drum. A raw cover is formed by sequentially forming and laminating various rubber members using a strip-wind method (STW method) which is spirally wound in a spiral manner.

  These rubber strips are manufactured using a rubber extrusion molding apparatus into which a warming-up extruder is incorporated (e.g., Patent Document 1).

  An example of such a rubber extrusion molding apparatus is shown in FIG. As shown in FIG. 3, this rubber extrusion molding apparatus 1 is equipped with a warming extruder 2, and the warming extruder 2 is accommodated in a cylinder 3 and is rotated by a motor 4, a screw 5, and a rubber composition And an extrusion head 6 having a die (die plate) provided with a discharge portion (opening) from which the ink is extruded.

  The configuration of a conventional hot-melt extruder provided in the rubber extrusion molding apparatus shown in FIG. 3 is shown in FIG. In FIG. 4, (a) is a front view, and (b) is a side view. As shown in FIG. 4, the rubber composition previously kneaded by a Banbury mixer or the like is further kneaded by the rotation of the screw 5 in the cylinder 3 after being introduced from the insertion port (not shown) of the warming extruder. While being heated by the frictional heat, it is sent to the rubber channel 9 of the extrusion head 6. Then, the rubber composition fed into the rubber flow path 9 is thereafter extruded from the opening 7 of a die (die plate) provided at the tip of the extrusion head 6 and further rolled into a predetermined shape by a calender roll not shown. And molded into a rubber strip.

JP, 2013-43317, A

  However, in the conventional hot-feed extruder, since the rubber composition fed in stays in the rubber flow path for a long time, vulcanization may be partially started due to heat, and so-called rubber burning may occur. .

  In particular, tires (TB tires) for large vehicles such as trucks and buses are required to have greater durability than tires for ordinary vehicles, so ply filler strips (P Although this P / F strip contains insoluble sulfur at a high ratio of 2.0 PHR or more in the compounding material, rubber scorch tends to occur.

  Therefore, according to the present invention, even if the rubber composition does not stay in the rubber flow path for a long time and is a rubber member containing insoluble sulfur at a high ratio like a P / F strip, the rubber is burned. It is an object of the present invention to provide a hot extrusion technique which can be appropriately heated and extruded without causing the occurrence of

  MEANS TO SOLVE THE PROBLEM This inventor earnestly studied about the solution of the said subject, discovers that the said subject can be solved by the invention described below, and came to complete this invention.

The invention according to claim 1 is
A screw is housed inside, and a cylinder for feeding out the introduced rubber composition while heating it to the extrusion head on the downstream side by the rotation of the screw, and a die provided at the tip with the rubber composition that has been delivered A heated extruder equipped with an extrusion head for extruding from the opening of
The opening of the die is formed into a one-letter shape with an opening width of 80 to 100% of the cylinder diameter and an opening gauge of 1.0 to 3.5 mm. .

The invention according to claim 2 is
The hot press extruder according to claim 1, wherein the opening of the die is formed in the shape of a letter in the horizontal direction.

The invention according to claim 3 is
The opening of the said base formed in the shape of one character is provided so as to intersect at an angle of 90 degrees, and the entire opening is formed in a cross shape. It is a hot-water extruder as described in 2.

The invention according to claim 4 is
Furthermore, the said extrusion head is provided with the temperature control means to adjust the temperature of the said extrusion head, It is a hot-rolling extruder of any one of the Claims 1 thru | or 3 characterized by the above-mentioned.

The invention according to claim 5 is
The said temperature control means is a temperature control means which adjusts the temperature of the said extrusion head to 50-90 degreeC, It is a hot-rolling extruder of Claim 4 characterized by the above-mentioned.

The invention according to claim 6 is
It is a rubber extrusion molding apparatus characterized by being equipped with the hot-water extruder according to any one of claims 1 to 5.

The invention according to claim 7 is
A rubber extrusion molding method for extrusion molding a rubber member using the rubber extrusion molding apparatus according to claim 6,
After the rubber composition introduced into the hot-pressing extruder is fed out while being heated up to the downstream extrusion head by the rotation of the screw housed in the cylinder,
Extruding at a predetermined speed from the opening of the die formed into a predetermined shape,
Furthermore, it is rolled into a predetermined shape by a calender roll to form a predetermined rubber member.

The invention according to claim 8 is
The rubber extrusion molding method according to claim 7, wherein the temperature of the extrusion head is adjusted to 50 to 90 ° C.

The invention according to claim 9 is
The rubber extrusion molding method according to claim 7 or 8, wherein the rubber member is a ply filler strip of a truck / bus tire.

  According to the present invention, even if the rubber composition does not stay in the rubber flow path for a long time and is a rubber member containing insoluble sulfur at a high ratio like a P / F strip, the rubber is burned. It is possible to provide a heated extrusion technique that can be appropriately heated and extruded without causing the occurrence of

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the hot-press extruder which concerns on the 1st Embodiment of this invention, (a) is a front view, (b) is a side view. It is a figure explaining the warming-up extruder based on the 2nd Embodiment of this invention, (a) is a front view, (b) is a side view. It is a figure which shows an example of a rubber extrusion molding apparatus. It is a figure which shows the structure of the conventional hot-press extruder, Comprising: (a) is a front view, (b) is a side view.

  Hereinafter, based on an embodiment, the present invention is concretely explained using a drawing.

1. First Embodiment The inventor conducted various experiments and examined the cause of occurrence of rubber scorch due to the rubber composition staying in the rubber flow path for a long time in the conventional hot-press extruder. As a result, in the conventional hot-press extruder, as shown in FIG. 4, the opening 7 of the die (die plate) is formed circular (diameter d), and the rubber flow path 9 of the extrusion head 6 is the opening 7 It turned out that it is the cause that it is formed in the shape of a cone.

  That is, in the conventional hot-press extruder, the rubber flow path 9 provided in the extrusion head 6 has a diameter from the outlet (diameter d1) of the circular cylinder 3 toward the circular opening 7 (diameter d) The volume of the space of the rubber flow passage 9 is large because it is formed in a conical shape so as to be gradually smaller. For this reason, the rubber composition retained in the conical rubber flow channel 9 is sent from the large diameter upstream side to the downstream small diameter opening 7 and the rubber flow channel of the rubber composition While the residence time at 9 is extended and the heated rubber composition becomes high temperature, the temperature is further raised by the friction between the rubber compositions moving toward the small diameter opening 7, As a result, it has been found that the occurrence of rubber burning is caused.

  Therefore, when the present inventor moves the staying rubber composition from the rubber flow channel 9 to the opening 7, the shape of the rubber flow channel 9 can be smoothly moved to the opening 7 without increasing the residence time. With respect to the shape of the opening 7 and the opening 7, earnestly examined.

  As a result, it has been found that occurrence of rubber burning can be prevented by changing the shape of the opening 7 from the conventional circular shape to the one-letter shape and changing the shape of the rubber flow channel 9 accordingly. And it turned out that it is more preferable to provide this one-letter opening in the horizontal direction.

  Hereinafter, the present embodiment will be specifically described. FIG. 1 is a view for explaining a hot-rolling extruder according to the present embodiment, wherein (a) is a front view and (b) is a side view.

  As shown in FIG. 1, the warming-up extruder according to the present embodiment is attached to a substantially cylindrical cylinder 3, a screw (not shown) accommodated in the cylinder 3, and the tip of the cylinder 3. The extrusion head 6 is similar to the conventional hot-feed extruder in that the extrusion head 6 has a die (not shown) provided with an opening.

  However, in the present embodiment, the shapes of the rubber flow path 9 and the opening 7 formed inside the extrusion head 6 are different from those of the conventional hot-rolling extruder.

  Specifically, as described above, the opening 7 is formed in a one-letter shape, and the rubber flow path 9 is formed accordingly. That is, in the present embodiment, when the rubber flow path 9 is narrowed at the end side of the cylinder 3 on the upstream side so that it is circular (diameter d1) decreases toward the downstream side, the horizontal direction In order to prevent the width d of the opening from decreasing significantly from the cylinder diameter d1, specifically, the width is set to 80 to 100% of the cylinder diameter d1. On the other hand, the gauge of the opening 7 (opening gauge) is thin according to the thickness of the rubber strip, specifically, 1.0 to 3.5 mm, and the opening 7 is formed in a one-letter shape as a whole .

  By forming the opening 7 of the die in such a shape and forming the rubber flow path 9 according to it, the rubber composition delivered from the screw in the cylinder 3 is not so narrow in the horizontal direction, and the horizontal direction In this state, the rubber composition is sent to the opening 7 so that the time for which the rubber composition stays in the rubber flow path 9 is shortened as compared with the prior art. Also, the rubber composition can be smoothly delivered without causing any extra friction. As a result, even in the case of a rubber material containing insoluble sulfur at a high ratio such as P / F strip, occurrence of rubber burn can be prevented, and a rubber strip of stable quality can be manufactured.

  In the present embodiment, it is preferable that the extrusion head 6 be provided with temperature control means for adjusting the temperature of the extrusion head 6. As a result, it is possible to prevent the occurrence of rubber burn more reliably by suppressing the temperature-sensitive rubber composition, such as P / F strip, from being exposed to excessively high temperature. Specifically, it is preferable that the temperature of the extrusion head 6 can be adjusted to 50 to 90 ° C., and more preferably 50 to 60 ° C.

  As such temperature control means, for example, temperature detection means such as a temperature sensor, cooling means such as a chiller cooling device, and the temperature of the cooling means based on the temperature of the extrusion head 6 detected by the temperature detection means. It can be configured by a combination of control means for controlling the operation.

2. Second Embodiment According to the above-described first embodiment, even in the case of a rubber material containing insoluble sulfur at a high ratio such as a P / F strip, occurrence of rubber burn can be prevented. It turned out that a rubber strip of stable quality could be produced, but when the surface of the extruded rubber strip was observed in detail, some compounding materials such as sulfur were transferred to the surface and crystallized. The rubber strip in which blooming has occurred may be produced, and it has been found that further improvement is necessary.

  In the case of a rubber material containing insoluble sulfur at a high ratio such as P / F strip, such blooming is considered to be sufficient to shorten the residence time in the rubber channel in the first embodiment described above. It can not be said that it occurs due to the time taken to cool the extruded rubber strip. Therefore, the inventor further conducted an experiment, and the time for the rubber composition to stay in the rubber flow path can be further shortened, and the rubber flow path and die (die plate) which can more smoothly deliver the rubber composition. We examined the shape of the opening of.

  As a result, two openings of the above-mentioned one character-like opening are provided so as to intersect at an angle of 90 degrees, the entire opening is formed in a cross shape, and the rubber flow path is formed accordingly. It turned out that it would be better.

  FIG. 2 is a view for explaining the hot-rolling extruder according to the present embodiment, in which (a) is a front view and (b) is a side view.

  As shown in FIG. 2, in the hot-rolling extruder according to the present embodiment, the end of the upstream side cylinder 3 is directed to the cross-shaped opening intersecting at an angle of 90 degrees with respect to the rubber flow passage 9. In the horizontal direction and the vertical direction, the opening width of the opening 7 is made to be 80 to 100% of the cylinder diameter d1 in the horizontal direction and the vertical direction as in the first embodiment. On the other hand, the gauge of the opening 7 (opening gauge) is also 1.0 to 3.5 mm as in the first embodiment.

  With such a configuration, the rubber composition moves more smoothly in a short period of time without concentrating in one place to the vicinity of the tip end of the extrusion head 6, and thereafter, it is horizontal from the cross-shaped opening 7 Since the extrusion is performed in the direction and the vertical direction, the residence time in the rubber flow path 9 can be further shortened, and the extruded rubber strip can be cooled quickly. As a result, blooming of compounding materials such as sulfur can be sufficiently prevented.

  Also in this embodiment, as a means for cooling the rubber composition more quickly, the extrusion head 6 is provided with a temperature control means for controlling the temperature of the extrusion head 6 as in the case of the first embodiment. Is preferred.

[1] Experiment 1
This experiment is an experiment which confirmed the effect by using the hot-press extruder in which the one-letter opening part was formed in the horizontal direction.

1. Production of rubber strip (1) Production of current rubber strip Extrusion of P / F strip (containing insoluble sulfur 2.0 PHR) for TB tires using a conventional hot-press extruder (without temperature control means) shown in FIG. 4 The molding was performed (300 m). The opening of the die was circular, and the diameter thereof was 40% that of the cylinder (diameter 90 mm).

(2) Preparation of test rubber strip P / F strip was extrusion-molded in the same manner as described above using the new type of hot-feed extruder shown in FIG. At this time, as shown in Table 1, the opening width of the die was changed to 50 to 100% of the cylinder (diameter 90 mm) ratio, and the opening gauge was changed to 0.5 to 4.0 mm. And here, the temperature of the extrusion head was adjusted to 60 ° C. using the temperature control means so that the temperature of the extruded P / F strip was 90 ° C. or less.

2. Evaluation Evaluation evaluated the temperature of each P / F strip immediately after being extruded. The results are shown in Table 1. In addition, the part enclosed with the thick line in Table 1 is an Example.

  As shown in Table 1, in the conventional hot-feed extruder, the temperature of the P / F strip exceeded 100 ° C. with most of the opening gauges, and it was not possible to prevent the occurrence of rubber scorch. Also, even in the case of a new type of hot-screw extruder, if the opening width is less than 80% or if the opening gauge is less than 1.0 mm, the temperature of the P / F strip similarly exceeds 100 ° C. It was not possible to prevent the occurrence of rubber burning. When the opening gauge exceeded 3.5 mm, the heated surface of the rubber surface became rough, and the sheet was perforated during rolling.

  On the other hand, when the opening width is 80% or more and the opening gauge is 1.0 to 3.5 mm, the temperature of the P / F strip is less than 100 ° C. to prevent occurrence of rubber burning. It was possible. Then, it can be seen from Table 1 that as the opening width is increased and the opening gauge is increased, the temperature of the P / F strip is lowered.

  However, when observing the surface of the P / F strip where rubber burning has not occurred, it is found that sulfur floats on the surface and blooms (blooming), and in order to prevent the occurrence of blooming, the temperature is further It turned out that it is necessary to try to reduce it.

[2] Experiment 2
This experiment is an experiment that verified that the occurrence of blooming can be prevented by using a warming extruder whose opening is formed in a cross shape in the horizontal direction and the vertical direction.

  The P / F strip was extruded in the same manner as in Experiment 1 except that the opening of the die was formed in a cross shape.

  In the evaluation, as in Experiment 1, the temperature of the P / F strip immediately after extrusion was measured, and the occurrence of the bloom was further evaluated. Here, with respect to the occurrence of bloom, the case where the occurrence occurred was evaluated as "not good" and the case where it did not occur was evaluated as "good".

  Table 2 shows the measurement results of the temperature of the P / F strip, and Table 3 shows the evaluation results of the occurrence of bloom. In addition, the place enclosed with the thick line like Example 1 is an Example. And, for comparison with the current, the current results are also described.

  From Table 2, as the opening width increases and the opening gauge increases, the temperature of the P / F strip decreases, and by forming the opening in a cross shape with the large gauge, the inside of the flow path of the rubber composition It can be seen that the retention at C. is more relaxed and the P / F strip can be cooled sufficiently. As a result, as shown in Table 3, the occurrence of bloom can be prevented.

  As mentioned above, although the present invention was explained based on an embodiment, the present invention is not limited to the above-mentioned embodiment. Various modifications can be made to the above embodiment within the same and equivalent scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Rubber extrusion molding apparatus 2 Hot-press extruder 3 Cylinder 4 Motor 5 Screw 6 Extrusion head 7 Opening 9 Rubber channel d Diameter or width of opening d Inner diameter of cylinder d

Claims (9)

A screw is housed inside, and a cylinder for feeding out the introduced rubber composition while heating it to the extrusion head on the downstream side by the rotation of the screw, and a die provided at the tip with the rubber composition that has been delivered A heated extruder equipped with an extrusion head for extruding from the opening of
An opening of the die is formed in a one-letter shape with an opening width of 80 to 100% of the cylinder diameter and an opening gauge of 1.0 to 3.5 mm.   The hot-pressing extruder according to claim 1, wherein the opening of the die is formed in a one-letter shape in the horizontal direction.   The opening of the said base formed in the shape of one character is provided so as to intersect at an angle of 90 degrees, and the entire opening is formed in a cross shape. The hot-water extruder according to 2.   Furthermore, the said extrusion head is provided with the temperature control means to adjust the temperature of the said extrusion head, The hot-water feeding extruder according to any one of claims 1 to 3 characterized by things.   The hot-rolling extruder according to claim 4, wherein the temperature control means is a temperature control means for controlling the temperature of the extrusion head to 50 to 90C.   A rubber extrusion molding apparatus comprising the hot-water extruder according to any one of claims 1 to 5. A rubber extrusion molding method for extrusion molding a rubber member using the rubber extrusion molding apparatus according to claim 6,
After the rubber composition introduced into the hot-pressing extruder is fed out while being heated up to the downstream extrusion head by the rotation of the screw housed in the cylinder,
Extruding at a predetermined speed from the opening of the die formed into a predetermined shape,
Furthermore, the rubber extrusion molding method characterized by rolling to a predetermined | prescribed shape with a calender roll, and shape | molding a predetermined | prescribed rubber member.   The rubber extrusion molding method according to claim 7, wherein the temperature of the extrusion head is adjusted to 50 to 90 ° C.   The rubber extrusion molding method according to claim 7 or 8, wherein the rubber member is a ply filler strip of a truck / bus tire.

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