JP2019059873A - Manufacturing method of rubber composition - Google Patents

Abstract

To provide a manufacturing method of a rubber composition capable of preventing opening/closing trouble of a drop door.SOLUTION: There is provided a manufacturing method of a rubber composition using a rubber kneader 1 having a chamber 2 having a space 2A for kneading a rubber composition 6 and an opening 2b for taking out a rubber to a lower part formed, a kneading rotor 3 for kneading the rubber composition 6 in the chamber 2, an electric motor 4 for driving the kneading rotor 3, and a drop door 5 for opening/closing the opening 2b of the chamber 2. It includes a kneading process S2 for kneading the rubber composition 6 in the chamber 2 by driving the kneading rotor 3 by the electric motor 4, and a door opening process S3 for controlling timing for opening the drop door 5 based on physical value relating to load on the electric motor 4, which is detected during the kneading process S2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a rubber composition using a rubber kneader.

  For example, Patent Document 1 below discloses a method for producing a rubber composition using a closed-type kneader equipped with a drop door. In the manufacturing method of Patent Document 1, in order to prevent defective opening and closing of the drop door, the step of kneading the rubber composition with a closed-type kneader, and the drop door when the temperature of the rubber composition reaches the first temperature And discharging the rubber composition from the kneader.

JP, 2017-30202, A

  However, since the rubber composition kneaded in the kneader does not have a uniform temperature distribution, the temperature varies largely depending on the measurement location. Therefore, when the kneading state is determined based on the temperature of the rubber composition, the rubber composition may be discharged without being sufficiently kneaded. In such a case, there is a problem that the rubber composition adheres to the discharge port and the drop door and the opening and closing of the drop door is still inhibited.

  The present invention has been made in view of the above-described actual situation, and has as its main object to provide a method for producing a rubber composition that can prevent defective opening and closing of a drop door.

  According to the present invention, there is provided a chamber having a space for kneading a rubber composition and having an opening for taking out rubber at a lower part thereof, a kneading rotor for kneading a rubber composition in the chamber, and the kneading A method for producing a rubber composition using a rubber kneader comprising an electric motor for driving a rotor and a drop door for opening and closing the opening of the chamber, wherein the electric motor drives the kneading rotor. By detecting the physical quantity associated with the load acting on the electric motor during the kneading step of kneading the rubber composition in the chamber, and the kneading step, the drop door is detected based on the physical amount And a door opening process for controlling the timing of opening the door.

  In the method of producing a rubber composition according to the present invention, the physical quantity is preferably a motor current value or a motor power consumption value.

  In the method of producing a rubber composition according to the present invention, it is preferable that the door opening step open the drop door when the physical quantity falls below a predetermined threshold.

  In the method of producing a rubber composition according to the present invention, the rubber kneader preferably includes a display device for displaying the physical quantity.

  The method for producing a rubber composition according to the present invention is associated with a kneading step of kneading a rubber composition in a chamber by driving a kneading rotor by an electric motor, and a load acting on the electric motor during the kneading step. And a door opening step of detecting the physical amount and controlling the timing of opening the drop door based on the physical amount.

  Generally, when the entire rubber composition is sufficiently kneaded in the kneading step, the flowability thereof is enhanced, and the load acting on the electric motor for driving the kneading rotor is reduced. In the manufacturing method of the present invention, in order to control the timing of opening the drop door based on the physical quantity associated with the load acting on the electric motor, the drop door may be opened with the entire rubber composition sufficiently kneaded. it can. As a result, adhesion of the rubber composition around the drop door and the opening can be reliably prevented.

It is a sectional view of a rubber kneader of one embodiment of the present invention. It is a flowchart which shows the manufacturing method of the rubber composition of this embodiment. It is a graph showing the relationship between the rotation speed of a kneading | mixing rotor, motor current, and time.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
FIG. 1 shows a cross-sectional view of a rubber kneader 1 used in the method for producing a rubber composition of the present embodiment. As shown in FIG. 1, the rubber kneader 1 includes a chamber 2, a kneading rotor 3, an electric motor 4, a drop door 5, and a control unit 10.

  The chamber 2 has a space 2A for kneading the rubber composition 6. In the upper part of the space 2A, an inlet 2a for inserting the rubber composition 6 is formed. In the lower part of the space 2A, an opening 2b for rubber removal after kneading is formed.

  The kneading rotor 3 is disposed in the chamber 2 to knead the rubber composition 6. In the present embodiment, two kneading rotors 3 are disposed in the chamber 2. The two kneading rotors 3 are arranged such that the rotation axes are parallel to each other. The two kneading rotors 3 are connected to each other, for example, via a drive gear 3b provided at an end in the rotational axis direction. Each kneading rotor 3 is formed with a wing portion 3 a protruding in a spiral shape. The two kneading rotors 3 rotate, for example, in opposite directions to each other, and the blade portions 3 a of the kneading rotor 3 knead the rubber composition 6 in the chamber 2.

  The electric motor 4 drives the kneading rotor 3 via the chain 11 and the gear 12. In the present embodiment, for example, the driving force of the electric motor 4 is transmitted to the drive gear 3b of the kneading rotor 3 via the chain 11 and the gear 12 to rotate the two kneading rotors 3 in opposite directions. A load acts on the electric motor 4 in accordance with the rotational resistance of the kneading rotor 3. For this reason, immediately after the start of kneading, the rubber composition 6 is not sufficiently kneaded, so that the rotational resistance of the kneading rotor 3 is large, and a large load acts on the electric motor 4. On the other hand, when the rubber composition 6 is sufficiently kneaded, the rotational resistance of the kneading rotor 3 becomes small, and the load acting on the electric motor 4 becomes small. In the present embodiment, the motor current value or the motor power consumption value is measured by the measurement unit 13 as a physical quantity indicating the load acting on the electric motor 4.

  The drop door 5 is provided to open and close the opening 2 b of the chamber 2. The drop door 5 of the present embodiment is, for example, provided so as to be movable downward with the door support 5 a formed on the main body of the rubber mixer 1 as a fulcrum. Further, the drop door 5 is locked by the lock means 5b in the closed state. The locking means 5b is released, and the chamber 2 is opened by moving the drop door 5 downward, so that the kneaded rubber composition 6 can be taken out.

  The control unit 10 can drive the kneading rotor 3 by the electric motor 4, for example. Further, the control unit 10 can stop the electric motor 4 and open the drop door 5 based on the physical quantity associated with the load acting on the electric motor 4. The physical quantity is, for example, a motor current value or a motor power consumption value of the electric motor 4 and is measured by the measurement unit 13.

  As a desirable mode, as for the rubber kneading machine 1 of this embodiment, the floating weight 7 is distribute | arranged to the upper part of the insertion port 2a. The floating weight 7 can bias the rubber composition 6 being kneaded downward by its own weight or the piston rod 7a attached to the upper part, and the rubber composition 6 can be easily kneaded. However, the rubber kneading machine 1 is not limited to such an aspect.

  FIG. 2 shows a flow chart of the method for producing the rubber composition of the present invention. As shown in FIG. 2, the method for producing a rubber composition of the present embodiment includes a rubber composition feeding step S1, a kneading step S2, a door opening step S3, and a rubber removing step S4.

  As shown in FIG. 1, in the rubber composition charging step S <b> 1, the rubber composition 6 is charged from the charging port 2 a of the chamber 2. In the present embodiment, thereafter, the floating weight 7 is disposed at the inlet 2a.

  In the kneading step S 2, the rubber composition 6 is kneaded in the chamber 2 by driving the kneading rotor 3 by the electric motor 4.

  In the door opening process S3, during the kneading process S2, a physical quantity associated with a load acting on the electric motor 4 is detected, and the timing at which the drop door 5 is opened is controlled based on the physical quantity. In the door opening process S3 of the present embodiment, the drop door 5 is opened when the physical quantity falls below a predetermined threshold.

  In the rubber removing step S4, the kneaded rubber composition 6 is removed from the opened opening 2b.

  Generally, when the entire rubber composition 6 is sufficiently kneaded in the kneading step S2, its fluidity is enhanced, and the load acting on the electric motor 4 for driving the kneading rotor 3 is reduced. In the manufacturing method of the present invention, since the timing at which the drop door 5 is opened is controlled based on the physical quantity associated with the load acting on the electric motor 4, the drop door 5 in a state where the entire rubber composition 6 is sufficiently kneaded. Can be opened. As a result, adhesion of the rubber composition 6 around the drop door 5 and the opening 2 b can be reliably prevented.

  In the present embodiment, the motor current value or the motor power consumption value measured by the measurement unit 13 is used as the physical quantity. Further, the control unit 10 of the present embodiment can automatically open the drop door 5 based on the motor current value or the motor power consumption value.

  The rubber kneader 1 preferably comprises, for example, a display 8 for displaying physical quantities. Thus, the operator can easily confirm the physical quantity.

  The rubber kneader 1 of the present embodiment can specify, for example, the number of rotations of the kneading rotor 3, and the display device 8 displays, for example, the number of rotations and the motor current value or motor power consumption value of the electric motor 4. can do. In a more desirable aspect, the display device 8 can output time-series graphed data on the number of rotations and the motor current value and the motor power consumption value.

  FIG. 3 shows a graph in which the vertical axis represents the number of rotations of the kneading rotor 3 and the motor current value, and the horizontal axis represents time t. In FIG. 3, a two-dot chain line indicates the number of rotations of the kneading rotor, and a solid line indicates the motor current value. As shown in FIG. 3, in the present embodiment, the kneading step S2 is performed between t = t1 and t2. In the kneading step S2, the number of rotations is appropriately changed.

  In the door opening process S3 of the present embodiment, when the motor current value falls below a predetermined threshold value a1, the drop door 5 is opened (t = t2), and the rubber removing process S4 is performed.

  In the present embodiment, it is desirable to lower the rotational speed of the kneading rotor 3 immediately before the door opening step S3 is performed in the kneading step S2. In general, when the rubber composition 6 is sufficiently kneaded, the motor current value also tends to decrease in proportion to the decrease of the rotation speed of the kneading rotor 3. In this embodiment, the rotation speed of the kneading rotor 3 is reduced before the door opening step S3 by utilizing such a tendency, and the change of the motor current value at that time is confirmed. An approximate mixing state can be estimated. In addition, when such an operation is added, the threshold value a1 according to it is predetermined.

  In a desirable mode, the rotation speed of the kneading rotor 3 is increased after the drop door 5 is opened. Thereby, the rubber composition 6 can be taken out quickly.

  As mentioned above, although the manufacturing method of the rubber composition of one embodiment of the present invention was explained in detail, the present invention is changed into various aspects, and is carried out, without being limited to the above-mentioned specific embodiment. obtain.

  As an example, a rubber kneader shown in FIG. 1 was prepared, and a rubber composition was produced by the above-mentioned production method. As a comparative example, a rubber composition was manufactured by a conventional manufacturing method in which the timing of opening the drop door is controlled by the temperature of the rubber composition. The amount of rubber attached to the drop door was confirmed for each manufacturing method.

<Rubber adhesion amount of drop door>
After removing the rubber composition from the chamber, the weight of the rubber composition attached to the drop door was measured. As the rubber adhesion amount of the drop door is smaller, it is shown that the rubber composition can be prevented from adhering to the vicinity of the drop door and the opening.
The results of the test are shown in Table 1.

  As a result of the test, in the manufacturing method of the comparative example, since the timing of opening the drop door is controlled by the temperature of the rubber composition, the drop door is opened in a state where the rubber composition is not sufficiently kneaded. There is a large amount of rubber adhesion on the door. On the other hand, in the manufacturing method of the embodiment, it is determined that the rubber composition has been sufficiently kneaded and the drop door is opened, so the amount of rubber adhesion is small, and in turn the opening / closing failure of the drop door is prevented. Was confirmed.

DESCRIPTION OF SYMBOLS 1 rubber kneading machine 2 chamber 2A space 2b opening part 3 kneading rotor 4 electric motor 5 drop door 6 rubber composition S2 kneading process S3 door opening process

Claims (4)

A chamber having a space for kneading the rubber composition and having an opening for taking out the rubber at the lower part, a kneading rotor for kneading the rubber composition in the chamber, and the kneading rotor driven A method of producing a rubber composition using a rubber kneader comprising an electric motor and a drop door for opening and closing the opening of the chamber,
Kneading the rubber composition in the chamber by driving the kneading rotor with the electric motor;
A door opening step of detecting a physical quantity associated with a load acting on the electric motor during the kneading step, and controlling a timing at which the drop door is opened based on the physical quantity;
Method of producing a rubber composition.   The method for producing a rubber composition according to claim 1, wherein the physical quantity is a motor current value or a motor power consumption value.   The method for producing a rubber composition according to claim 1 or 2, wherein the door opening step opens the drop door when the physical quantity falls below a predetermined threshold.   The method for producing a rubber composition according to any one of claims 1 to 3, wherein the rubber kneader comprises a display device for displaying the physical quantity.

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