JP2005001231A - Rubber continuous kneading extruder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber continuous kneading extruder capable of sufficiently kneading a rubber and capable of suppressing the rise in the temperature of the rubber caused by generation of heat. <P>SOLUTION: In the rubber continuous kneading extruder 1 equipped with a rubber supply part 2 for receiving the supply of a rubber material, a screw 5, the cylinder 4 arranged to the outer periphery of the screw 5 and a cooling part arranged in at least one of the cylinder or the screw, the screw 5 is equipped with a screw shaft and a large number of screw elements 50-54 inserted along the screw shaft. The screw elements are constituted of at least the first elements 50 and 52 for forming a feed zone A, the second elements 51 and 54 for forming a kneading zone C and the third element 53 for forming a cooling zone D. The feed zone A, the kneading zone C and the cooling zone D are formed along the shaft direction of the screw and the cooling zone D is formed at the extrusion downstream side of the kneading zone C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber continuous kneading extrusion system including a rubber supply unit to which a rubber material is supplied, a screw, a cylinder disposed on the outer periphery of the screw, and a cooling unit disposed in at least one of the cylinder and the screw. Related to the machine.
[0002]
[Prior art]
The rubber kneading step can be roughly classified into non-pro kneading (kneading using a chemical other than a vulcanizing agent), final kneading (kneading using a vulcanizing agent), and re-kneading. For rubber kneading, batch systems such as Banbury mixers and kneaders have been the mainstream, but in recent years, continuous systems using single or biaxial continuous kneading extruders have also been performed. In the rubber kneading, the rubber generates heat and the temperature rises due to the shearing force accompanying the rotation of the screw of the extruder. Due to this temperature rise, the rubber clay is lowered, so that there is a problem that kneading is not sufficiently performed. Particularly in the final kneading, since a vulcanizing agent is used as a chemical, if the temperature of the rubber rises, a problem of rubber burn (scorch) also occurs. Therefore, the rubber must be discharged from the extruder at a predetermined rubber temperature, and it is difficult to obtain a uniform mixed state of rubber and drug.
[0003]
In order to suppress the temperature rise due to heat generation of such rubber, a method of kneading while cooling has been conventionally performed. For example, in a batch system such as a kneader, the cooling during rubber kneading is generally performed by passing cold water through a rotor or a chamber. However, in this cooling method, the cooling effect as expected cannot be obtained, and the heat generation of rubber becomes dominant. Therefore, the rubber temperature becomes high in a short time. When the temperature of the rubber becomes high, the shearing force hardly acts even if kneading is performed, and the efficiency becomes extremely low. In order to compensate for such inadequate kneading, it is necessary to discharge the rubber once and cool it down, and then knead the rubber again (re-kneading). Therefore, the number of kneading steps increases and the productivity also decreases.
[0004]
On the other hand, in a single-screw or twin-screw continuous kneading extruder, a conveyance zone and a kneading zone are formed along the axial direction of the screw. As a method of cooling the rubber, a method of cooling by passing a refrigerant (water) through a screw or a cylinder (barrel) is generally performed. In addition, there is a cooling method as disclosed in Patent Documents 1 and 2 below.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 64-71708 [Patent Document 2]
JP-A-6-238656 [0006]
[Problems to be solved by the invention]
As described above, even when the water is passed through the screw or the cylinder, it is still sufficient because the efficiency of the kneading action is lowered when the temperature of the rubber becomes high due to the kneading action in the kneading zone. That's not true. Therefore, it is necessary to adjust the kneading action by various factors such as throughput per unit time, screw shape, screw rotation speed, kneading zone length, etc., so that the rubber temperature does not become too high due to kneading in the kneading zone. There is.
[0007]
The present invention has been made in view of the above circumstances, and the problem is that the rubber can be sufficiently kneaded in a single step, and the increase in the rubber temperature in the kneader due to the heat generation of the rubber can be suppressed. An object of the present invention is to provide a rubber continuous kneading extruder capable of achieving the effect of lowering the temperature of discharged rubber.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the rubber continuous kneading extruder according to the present invention is:
Rubber continuous kneading comprising a rubber supply part to which a rubber material is supplied, a screw, a cylinder arranged on the outer periphery of the screw, and a cooling part arranged in at least one (preferably both) inside the cylinder and inside the screw An extruder,
The screw includes a screw shaft and a number of screw elements inserted along the screw shaft,
The screw element is composed of at least a first element for forming a transport zone, a second element for forming a kneading zone, and a third element for forming a cooling zone,
A conveying zone, a kneading zone, and a cooling zone are formed along the axial direction of the screw, and a cooling zone is formed on the downstream side of extrusion of the kneading zone.
[0009]
The operation and effect of the rubber continuous kneading extruder with this configuration is as follows. First, the screw includes a screw shaft and a large number of screw elements inserted along the screw shaft. The screw element can be prepared in various shapes in advance, a first element for forming a transport zone, a second element for forming a kneading zone, and a cooling zone A third element is prepared as a screw element. Of course, other target zones (for example, deaeration zones) may be added. A cooling zone is set downstream of the kneading zone. Accordingly, when the rubber is kneaded in the kneading zone and generates heat, it continues to be cooled in the cooling zone. Thereby, it can adjust to a suitable rubber temperature. Moreover, as a cooling part, it can equip with at least one inside a screw inside and a cylinder inside, Preferably both. The heat generation of the rubber can be effectively suppressed by the cooling function of the cooling section and the cooling zone by the screw. As a result, rubber kneading and extrusion can be performed sufficiently in a single process, and can suppress the rise in the temperature of the rubber in the kneader due to the heat generated by the rubber and / or achieve the effect of lowering the temperature of the discharged rubber. Machine can be provided.
[0010]
In order to solve the above problems, another rubber continuous kneading extruder according to the present invention is:
Rubber continuous kneading comprising a rubber supply part to which a rubber material is supplied, a screw, a cylinder arranged on the outer periphery of the screw, and a cooling part arranged in at least one (preferably both) inside the cylinder and inside the screw An extruder,
The screw is characterized in that at least a conveying zone, a kneading zone, and a cooling zone are formed along the axial direction of the screw, and a cooling zone is formed on the downstream side of the extrusion of the kneading zone. is there.
[0011]
The operation and effect of the rubber continuous kneading extruder with this configuration is as follows. First, this screw has a structure in which a screw shaft and a screw blade are integrated, unlike the configuration using the screw element. This screw has at least a conveyance zone, a kneading zone, and a cooling zone formed along the screw axis. Of course, other target zones (for example, deaeration zones) may be added. A cooling zone is set downstream of the kneading zone. Accordingly, when the rubber is kneaded in the kneading zone and generates heat, it continues to be cooled in the cooling zone. Thereby, it can adjust to a suitable rubber temperature. Moreover, as a cooling part, it can equip with at least one inside a screw inside and a cylinder inside, Preferably both. The heat generation of the rubber can be effectively suppressed by the cooling function of the cooling section and the cooling zone by the screw. As a result, rubber kneading and extrusion can be performed sufficiently in a single process, and can suppress the rise in the temperature of the rubber in the kneader due to the heat generated by the rubber and / or achieve the effect of lowering the temperature of the discharged rubber. Machine can be provided.
[0012]
When a plurality of kneading zones are provided, it is not necessary to provide a cooling zone on the downstream side of all the kneading zones. What is necessary is just to arrange | position a cooling zone so that it may not become more than predetermined temperature.
[0013]
As a preferred embodiment of the present invention, in the cooling zone, one in which screw blades are formed in at least two strips can be mentioned.
[0014]
If there are at least two strips, the contact area between the rubber and the screw element can be increased. And by comprising a cooling part inside a screw, it can exchange heat efficiently with the refrigerant | coolant of a cooling part. Therefore, the cooling effect can be enhanced.
[0015]
As another preferred embodiment of the present invention, the screw blades in the cooling zone may have a screw blade pitch shorter than that in the transport zone.
[0016]
By shortening the pitch of the screw blades, the residence time in the rubber cooling zone is increased. Thereby, heat can be efficiently exchanged with the refrigerant in the cooling part inside the screw or inside the cylinder. Therefore, the cooling effect can be enhanced.
[0017]
As still another preferred embodiment of the present invention, the screw blades in the cooling zone may have a shaft diameter larger than that in the transport zone.
[0018]
Since the conveying rubber lump is crushed by increasing the shaft diameter, the surface area of the rubber lump increases. Therefore, heat can be efficiently exchanged with the refrigerant in the cooling section by configuring the cooling section inside the screw and in the cylinder section. Therefore, the cooling effect can be enhanced.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an internal configuration of a single-screw continuous kneading extruder 1.
[0020]
The extruder 1 is used for final kneading of rubber, and includes a rubber supply unit 2 to which rubber is supplied and a chemical supply unit 3 to which a chemical containing a vulcanizing agent is supplied. Non-vulcanizable pellet rubber is supplied from the rubber supply unit 2. The rubber can be supplied in sheet form, strand form, ribbon form, or other forms. The drug is supplied from the drug supply unit 3 by a screw feeder, but the supply form may be other methods. The medicine supply unit 3 is provided on the downstream side of the rubber supply unit 2.
[0021]
The rubber supplied from the rubber supply unit 2 moves from the left side to the right side in FIG. 1 and is extruded with a predetermined cross-sectional shape by a die (not shown) or supplied to another extruder. A screw 5 is provided along the extrusion direction, and is driven to rotate and advance by a driving device 6. A cylinder 4 (barrel) having an inner surface formed in a cylindrical shape is provided around the screw 5. As this continuous kneading extruder, a known screw type continuous kneading machine (“CONEDER” manufactured by BUSS) can be used.
[0022]
The screw 5 includes a screw shaft and a number of screw elements inserted into the screw shaft. Various types of screw elements can be used. Each functional zone is set along the axial direction of the screw shaft. Specifically, the conveyance zone A → the plasticizing zone B → the conveyance zone A → the kneading zone C → the cooling zone D → the kneading zone C → the cooling zone D is set in order from directly below the rubber supply unit 2. In the case of plasticized rubber, the plasticizing zone can be omitted. The appropriate element for each zone is used. The kneading zone C starts from the immediately downstream side of the medicine supply unit 3, and the cooling zone D is set on the downstream side of the kneading zone C. The first conveying zone A has two first elements 50, the second conveying zone A has two first elements 52, the plasticizing zone B has one fourth element 51, the first kneading zone C Includes one second element 51, two second elements 51 and 54 in the second kneading zone C, two third elements 53 in the first cooling zone D, and second elements. The cooling zone D is also provided with two third elements. The arrangement of each element can be freely changed.
[0023]
Comparing the transport zone A and the kneading zone C, the pitch of the screw blades in the kneading zone C is half that of the transport zone A. Further, the screw blades in the kneading zone C have a plurality of notches formed in the circumferential direction. As this screw blade | wing, it is disclosed by Unexamined-Japanese-Patent No. 2000-43032 by this applicant, for example. Further, in the kneading zone C, a shear pin 7 projects from the inner surface of the barrel. A shearing force is generated by the shear pin 7 to enhance the kneading effect. The configuration of the plasticizing zone B is set to be the same as that of the kneading zone C.
[0024]
Next, the screw element for constituting the cooling zone D will be described with reference to FIGS. First, FIG. 2 shows a configuration of a screw element provided in the transport zone A. This element includes a main body portion 60 and a blade portion 60a. The main body portion 60 has a through hole formed therein, and is configured to be inserted into a screw shaft. An engagement tooth portion 60b is formed on the inner wall surface of the through hole, and an engagement tooth portion that meshes with the screw shaft is also formed. In addition, although the notch is formed in the element used for the kneading zone C, the notch is not formed in the element provided in other zones, and the blades are connected.
[0025]
FIG. 3 is a diagram illustrating a configuration of a cooling zone element (third element) according to the first embodiment. This element includes a main body 61 and screw blades 61a and 61b. The point is that the screw blades 61a, 61b are two. As will be described later, a cooling unit is provided inside the screw 5 and water as a refrigerant is circulated. Similarly, a cooling unit is provided inside the cylinder 4. By setting the screw blades to two (or three or more), the contact area between the rubber and the screw can be increased. Therefore, heat exchange with water can be performed efficiently. Thereby, the temperature rise by the heat_generation | fever of rubber | gum can be suppressed. The main body portion 61 is provided with an engaging tooth portion 61c for attaching to the screw shaft.
[0026]
FIG. 4 is a diagram illustrating a configuration of an element for a cooling zone according to the second embodiment. This element includes a main body 62 and screw blades 62a. The pitch of the screw blades 62a is 2/3 compared to the elements in the transport zone. The pitch may be set to 2/3 or less. Thereby, the residence time of the rubber | gum in a cooling zone can be increased. Thereby, heat exchange with the cooling water inside a screw or a cylinder can be performed efficiently. An engaging tooth portion 62b is provided on the inner wall surface of the through hole of the main body portion 62 as before.
[0027]
FIG. 5 is a diagram illustrating a configuration of an element for a cooling zone according to the third embodiment. In this element, the outer diameter A of the main body 63 is 1.125 times larger than that in the transport zone. The screw blade 63a may be the same as in FIG. By increasing the outer diameter A, the surface area of the main body 63 can be increased. Moreover, since the rubber lump to be conveyed is crushed, the surface area of the rubber can be increased. Thereby, heat exchange with the cooling water and rubber inside a screw can be performed efficiently. It should be noted that how much the outer diameter A is increased can be set as appropriate. An engagement tooth portion 63 b is provided on the inner wall surface of the through hole of the main body portion 63.
[0028]
As other configuration examples, the configurations from the first embodiment to the third embodiment can be arbitrarily combined. For example, the outer diameter may be increased and the number of screw blades may be two.
[0029]
1 to 5, in order to configure each zone, a configuration in which a screw element having a shape suitable for each zone is inserted along the screw shaft has been described, but the screw shaft and the screw blade are integrated. You may use the screw of the structure made.
[0030]
Next, the configuration of the cooling unit will be described with reference to FIGS. FIG. 6 shows a conventional structure, and FIG. 7 shows a novel structure. The structures shown in FIGS. 6 and 7 can be adopted regardless of the type of screw element used in the cooling zone.
[0031]
First, in FIG. 6, barrels 42 and 43 are provided inside the cylinders 40 and 41. The barrels 42 and 43 are formed in a thin annular shape. The cylinders 40 and 41 may have a structure that can accommodate the barrels 42 and 43 on the inner surfaces thereof. Further, cooling water passages 40a and 41a are provided as cooling portions, and allow the cooling water to pass therethrough. Further, the shear pin 7 is attached to the barrel 43. Moreover, the cross-sectional shape of the screw is shown on the right side of FIG. Inside the screw shaft 21, cooling water passages 21b and 21c are provided as cooling portions. The outside constitutes the forward path for circulating water, and the center side constitutes the return path. The screw element 20 includes a screw blade 20a, a main body portion 20b, and an engagement tooth portion 20c. The engagement tooth portion 20c engages with the engagement tooth portion 21a of the screw shaft 21 to realize a strong engagement state.
[0032]
7 is the same as FIG. 6 in that cylinders 40 and 41 and cooling water passages 40a and 41a are provided, but there is no barrel equivalent. The shear pin 7 is attached to the cylinder 41. Thus, the cooling water passages 40a and 41a can be brought closer to the rubber as much as there is no barrel. Thereby, heat exchange can be performed efficiently. The screw structure is the same in that cooling water passages 23 b and 23 c are provided inside the screw shaft 23. Further, the screw shaft 23 and the screw blade 23a are integrated. Thereby, since a cooling part can be brought close to the screw surface, heat exchange can be performed efficiently.
[0033]
In the cooling zone, it is preferable to take measures such as increasing the refrigerant flow rate so as not to impair the heat exchange efficiency.
[0034]
<Another embodiment>
(1) A medium other than cooling water may be used as the refrigerant used in the cooling unit.
(2) The setting of the zone is not limited to the contents shown in FIG. In the present embodiment, the kneading zone and the cooling zone are set twice, but may be set once without repetition or may be repeated three or more times.
[0035]
(3) In the present embodiment, the configuration for file kneading has been described, but the present invention can also be applied to non-pro kneading and re-kneading.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an internal configuration of a continuous kneading extruder. FIG. 2 is a diagram showing a screw element in a conveyance zone. FIG. 3 is a diagram showing a configuration of an element for a cooling zone according to a first embodiment. FIG. 5 is a diagram showing a configuration of an element for a cooling zone according to a second embodiment. FIG. 5 is a diagram showing a configuration of an element for a cooling zone according to a third embodiment. FIG. 6 is a diagram showing a configuration of a cooling unit. 7] Diagram showing a preferred cooling unit configuration [Explanation of symbols]
A Conveying zone B Plasticizing zone C Kneading zone D Cooling zone 2 Rubber supply part 3 Drug supply part 4 Cylinder 5 Screw 50, 51, 52, 53, 54 Element

Claims (5)

A rubber continuous kneading and extruding machine comprising a rubber supply unit to which a rubber material is supplied, a screw, a cylinder disposed on the outer periphery of the screw, and a cooling unit disposed in at least one of the inside of the cylinder and the inside of the screw. ,
The screw includes a screw shaft and a number of screw elements inserted along the screw shaft,
The screw element is composed of at least a first element for forming a transport zone, a second element for forming a kneading zone, and a third element for forming a cooling zone,
A rubber continuous kneading and extruding machine characterized in that a conveying zone, a kneading zone, and a cooling zone are formed along the axial direction of the screw, and a cooling zone is formed on the downstream side of extrusion of the kneading zone. A rubber continuous kneading and extruding machine comprising a rubber supply unit to which a rubber material is supplied, a screw, a cylinder disposed on the outer periphery of the screw, and a cooling unit disposed in at least one of the inside of the cylinder and the inside of the screw. ,
A continuous rubber is characterized in that at least a conveying zone, a kneading zone, and a cooling zone are formed in the screw along the axial direction of the screw, and a cooling zone is formed downstream of the kneading zone. Kneading extruder. The rubber continuous kneading and extruding machine according to claim 1 or 2, wherein the cooling zone has at least two screw blades. The rubber continuous kneading extruder according to any one of claims 1 to 3, wherein the screw blades of the cooling zone have a shorter pitch of the screw blades than the conveying zone. The rubber continuous kneading extruder according to any one of claims 1 to 4, wherein the screw blades in the cooling zone have a thicker shaft diameter than the conveying zone.

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