JP6769184B2 - Kneading method and equipment for rubber materials - Google Patents

Description

The present invention relates to a method and an apparatus for kneading a rubber material, and more specifically, a rubber material capable of obtaining a rubber material having stable quality while preventing the compounding agent charged into the kneading chamber of a closed kneader from being ejected. It relates to a kneading method and an apparatus.

When manufacturing rubber products such as tires, there is a kneading process in which various compounding agents are dispersed in raw rubber and kneaded to obtain an unvulcanized rubber material. In this kneading step, for example, a closed kneader is used. In the closed type kneader, a rotor is installed internally in the kneading chamber, and a ram weight that moves up and down is arranged above the kneading chamber. The raw rubber and various compounding agents put into the kneading chamber are kneaded by a rotating rotor in a kneading chamber in a state where the upper part is closed with a ram weight (see, for example, Patent Document 1).

During this kneading, the ram weight functions as a lid of the kneading chamber to prevent the compounding agent from being ejected from the kneading chamber. However, immediately after the compounding agent is put into the kneading chamber, the apparent volume of the kneading chamber is large, and the ram weight is lowered to the lower limit position. At this time, if the kneading chamber is filled with rubber materials (raw rubber and compounding agent), excessive pressure acts on the rubber material in the kneading chamber, and the compounding agent that easily scatters from the gap between the kneading chamber and the ram weight. It may spurt out of the kneading chamber. When the compounding agent is ejected from the kneading chamber, the quality of the kneaded rubber material varies due to the insufficient amount of the compounding agent.

On the other hand, unless the kneading step is performed with the ram weight arranged at the lower limit position, the compounding agent cannot be sufficiently dispersed and kneaded with the raw rubber. In this case as well, the quality of the kneaded rubber material varies, so that a rubber material with stable quality cannot be obtained.

Japanese Patent Application Laid-Open No. 9-254148

An object of the present invention is to provide a method and an apparatus for kneading a rubber material capable of obtaining a rubber material having stable quality while preventing the compounding agent charged into the kneading chamber of the closed type kneader from being ejected.

In the method for kneading the rubber material of the present invention for achieving the above object, a rubber material composed of a raw material rubber and a compounding agent is kneaded in a kneading chamber of a closed type kneader, and a ram weight is arranged above the kneading chamber. In the method of kneading a rubber material to be kneaded by a rotating rotor, after the rubber material is put into the kneading chamber, the filling state of the rubber material in the kneading chamber is grasped from the data acquired from the sensor, and based on the data. When it is determined that the internal pressure of the kneading chamber becomes larger than the preset allowable pressure when the ram weight is moved downward to the lower limit position by controlling the vertical movement of the ram weight, the ram weight is moved to the lower limit position. The rotor is stopped at a predetermined position above the position, the rotor is rotated in this state to pre-knead the rubber material, and then the ram weight is moved to the lower limit position to be stopped, and the rotor is rotated in this state. It is characterized in that the rubber material is kneaded.

The rubber material kneading device of the present invention has a rotor installed in the kneading chamber and a ram weight that is arranged above the kneading chamber and moves up and down, and is a rubber material composed of a raw material rubber and a compounding agent. In a rubber material kneading device provided with a closed-type kneader that kneads the rubber material in the kneading chamber by rotating the rotor, a sensor that acquires data for grasping the filling state of the rubber material in the kneading chamber, and It has a control unit into which the acquired data is input, and after the rubber material is put into the kneading chamber, the control unit controls the vertical movement of the ram weight based on the data to obtain the ram weight. When the control unit determines that the internal pressure of the kneading chamber becomes larger than the preset allowable pressure when moved downward to the lower limit position, the ram weight is stopped at a predetermined position above the lower limit position. In this state, the rotor is rotated to pre-knead the rubber material, then the ram weight is moved to the lower limit position to stop, and the rotor is rotated in this state to knead the rubber material. It is characterized by that.

According to the present invention, after the rubber material is put into the kneading chamber, the filling state of the rubber material in the kneading chamber is grasped from the data acquired from the sensor, and the ram weight is moved up and down based on the data. Take control. Here, when it is determined that the internal pressure of the kneading chamber becomes larger than the preset allowable pressure when the ram weight is moved downward to the lower limit position, there is a high possibility that the compounding agent is ejected from the kneading chamber. The rubber material is pre-kneaded by stopping the ram weight at a predetermined position above the lower limit position. As a result, excessive pressure does not act on the rubber material in the kneading chamber, and the ejection of the compounding agent can be prevented.

After this pre-kneading, the ram weight is stopped at the lower limit position to knead the rubber material. As a result, the compounding agent can be sufficiently dispersed and kneaded with respect to the raw rubber, so that a rubber material having stable quality can be obtained.

It is explanatory drawing which illustrates the kneading apparatus of the rubber material of this invention. It is sectional drawing of AA of FIG. It is explanatory drawing which illustrates the state in which the rubber material is pre-kneaded by stopping the ram weight of FIG. 1 at a predetermined position above the lower limit position. It is explanatory drawing which illustrates the state which the rubber material is kneaded by stopping the ram weight at the lower limit position after the preliminary kneading of FIG. It is explanatory drawing which illustrates another embodiment of the kneading apparatus of the rubber material of this invention. It is explanatory drawing which illustrates still another embodiment of the kneading apparatus of the rubber material of this invention.

Hereinafter, the method and apparatus for kneading the rubber material of the present invention will be described based on the embodiment shown in the figure.

The rubber material kneading device 1 (hereinafter referred to as kneading device 1) of the present invention exemplified in FIGS. 1 and 2 kneads the unvulcanized rubber material R. The rubber material R is composed of the raw material rubber G and a plurality of types of non-vulcanizing compounding agents N, and by kneading the rubber material R, the compounding agent N is evenly dispersed in the raw material rubber G to obtain a rubber material R having an appropriate viscosity. To do.

The raw material rubber G includes natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), 1,2-polybutadiene, chloroprene rubber, butyl rubber, styrene-butadiene rubber (SBR), and nitrile rubber (acrylic nitrile rubber, Nitrile hydride rubber), ethylene propylene diene rubber and the like can be exemplified. These may be used alone or in combination of two or more. As the compounding agent N, for example, carbon black, silica, a silane coupling agent, zinc oxide, stearic acid and the like are appropriately used.

The kneading device 1 is a closed type kneader 2 such as a Banbury mixer, a sensor 13 that acquires data for grasping a filling state of the rubber material R in the kneading chamber 4a of the closed type kneader 2, and a sensor 13 acquired by the sensor 13. It is provided with a control unit 12 into which the input data is input. In this embodiment, the load cell 13a is used as the sensor 13.

The closed type kneader 2 includes a kneading chamber 4a and a ram weight chamber 4b connected above the kneading chamber 4a, and the kneading chamber 4a includes a pair of rotors 3 and an oil charging unit 5 arranged opposite to each other. Is provided. A blade 3b is projected from the rotating shaft 3a of each rotor 3, and the rotating shafts 3a arranged in parallel are rotationally driven by a drive motor. The rotation of the rotor 3 is controlled by the control unit 12.

A discharge door 10 that opens and closes is provided on the bottom surface of the kneading chamber 4a, and a thermometer 11 is provided with its tip exposed to the kneading chamber 4a. The thermometer 11 sequentially detects the temperature of the rubber material R kneaded in the kneading chamber 4a. The temperature data from the thermometer 11 is input to the control unit 12.

In the ram weight chamber 4b, a ram weight 8 that moves up and down to adjust the internal pressure (ram pressure) of the kneading chamber 4a is arranged. The ram weight 8 is moved up and down by an elevating mechanism 8a such as a hydraulic cylinder, and the up and down movement (vertical position and elevating speed) of the ram weight 8 is controlled by the control unit 12. The drawing shows a lower limit position LP (the position of the upper surface of the ram weight 8 when the ram weight 8 is most lowered) in which the ram weight 8 can move, and a predetermined position PP above the lower limit position LP. The ram weight chamber 4b is further provided with a rubber charging section 6 for charging the raw rubber G and a compounding agent charging section 9 for charging the compounding agent N from the hopper 7.

A power meter 12a is attached to the control unit 12. The instantaneous power required for rotationally driving the rotor 3 is sequentially detected by the power meter 12a. The instantaneous power detected by the wattmeter 12a is input to the control unit 12. The control unit 12 calculates the integrated electric energy by integrating the instantaneous electric power, and can grasp the electric energy (load acting on the rotor 3) required for rotationally driving the rotor 3 in an arbitrary kneading period. In addition, the rotation speed of the rotor 3 and the like are input to the control unit 12.

Further, in the control unit 12, when the ram weight 8 is moved downward to the lower limit position LP with the rubber material R charged into the kneading chamber 4a, the internal pressure of the kneading chamber 4a is a guideline for preventing the ejection of the compounding agent N. As, a preset allowable pressure range is input. Further, according to the specifications of the rubber material R to be kneaded, the optimum predetermined temperature range of the rubber material R to be maintained during kneading is also input to the control unit 12. Then, the rotation speed of the rotor 3 is controlled based on the temperature detected by the thermometer 11. Basically, the higher the rotation speed of the rotor 3 (increasing the rotation speed), the higher the temperature of the kneaded rubber material R.

Hereinafter, the procedure of the kneading method for the rubber material of the present invention will be described.

First, a predetermined amount of raw rubber G is charged into the kneading chamber 4a through the rubber charging unit 6, and kneading is performed by rotating the rotor 3. After the raw rubber G is appropriately kneaded, a predetermined amount of the required type of compounding agent N is charged into the kneading chamber 4a through the compounding agent charging section 9.

After that, the ram weight 8 is moved downward toward the lower limit position LP, and at that time, the load data that the lower surface of the ram weight 8 receives from the rubber material R put into the kneading chamber 4a is acquired by the load cell 13a. Specifically, when the ram weight 8 is continuously moved downward, the lower surface of the ram weight 8 comes into contact with the rubber material R filled in the kneading chamber 4a. In this contact state, the load cell 13a acquires the load received from the rubber material R on the lower surface of the ram weight 8. The load data acquired by the load cell 13a is input to the control unit 12.

The load data becomes larger as the load cell 13a moves downward, and the load data becomes larger as the amount (volume) of the rubber material R filled in the kneading chamber 4a is larger. Therefore, the filling state of the rubber material R in the kneading chamber 4a can be grasped from the vertical position of the ram weight 8 and the size of the load data acquired by the load cell 13a.

Then, the control unit 12 determines whether or not the internal pressure of the kneading chamber 4a becomes larger than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP based on the size of the load data acquired by the load cell 13a. To do. When the internal pressure of the kneading chamber 4a is larger than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP, the kneading chamber 4a is filled with the rubber material R or overflows from the kneading chamber 4a. It is in a state of being.

Here, when the control unit 12 determines that the internal pressure of the kneading chamber 4a becomes larger than the allowable pressure, the ram weight 8 is stopped at a predetermined position PP above the lower limit position LP, as illustrated in FIG. Then, in this state, the rotor 3 is rotated for a predetermined time to pre-knead the rubber material R. Oil is timely charged into the kneading chamber 4a through the oil charging unit 5.

This predetermined position PP is set at a position that is 1% to 10% higher than the lower limit position LP, for example, the outer diameter of the rotor 3 (the diameter formed by the rotation locus of the outer edge of the blade 3b). When the predetermined position PP is higher than the lower limit position LP by less than 1% of the outer diameter of the rotor 3, the effect of preventing the compounding agent N from being ejected becomes small, and when the position is higher than 10%. It becomes difficult to sufficiently knead the compounding agent N into the raw material rubber G. It is more preferable to set this range to about 3% (2% or more and 4% or less).

In the pre-kneading, since the ram weight 8 is arranged at the predetermined position PP, the rubber material R in the kneading chamber 4a is not excessively compressed by the ram weight 8. Therefore, it is possible to prevent the compounding agent N from being ejected from the gap between the kneading chamber 4a and the lamb weight 8.

By the pre-kneading, the compounding agent N is kneaded and dispersed in the raw rubber G to some extent, and the volume of the rubber material R is reduced. Then, as illustrated in FIG. 4, the ram weight 8 is moved downward to the lower limit position LP and stopped. In this state, the rotor 3 is rotated to knead the rubber material R. For example, the rubber material R is kneaded while maintaining the temperature range to obtain a rubber material R having a desired viscosity. Oil is timely charged into the kneading chamber 4a through the oil charging unit 5. In the kneading in this state, a sufficient load can be applied to the rubber material R by the ram weight 8, so that the compounding agent N can be dispersed more uniformly.

On the other hand, when the control unit 12 determines that the internal pressure of the kneading chamber 4a becomes equal to or less than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP, the ram weight 8 is not set to the predetermined position PP. , Immediately move downward to the lower limit position LP and stop as illustrated in FIG.

When the internal pressure of the kneading chamber 4a is equal to or less than the allowable pressure, it means that the kneading chamber 4a is not filled with the rubber material R. Therefore, even if the ram weight 8 is moved downward to the lower limit position LP, the rubber material R in the kneading chamber 4a is not excessively compressed by the ram weight 8. Therefore, it is possible to prevent the compounding agent N from being ejected from the gap between the kneading chamber 4a and the ram weight 8 without performing the pre-kneading described above.

Then, the rotor 3 is rotated with the ram weight 8 stopped at the lower limit position LP to knead the rubber material R. For example, the rubber material R is kneaded while maintaining the temperature range to obtain a rubber material R having a desired viscosity. In the kneading in this state, a sufficient load can be applied to the rubber material R by the ram weight 8, so that the compounding agent N can be dispersed more uniformly.

As described above, in the present invention, based on the load data acquired by the load cell 12a, it is determined that the internal pressure of the kneading chamber 4a becomes larger than the preset allowable pressure when the ram weight 8 is moved downward to the lower limit position LP. Kneading is performed by controlling the vertical position of the ram weight 8 to be different between the time and the time when it is determined that the pressure is equal to or lower than this allowable pressure. Therefore, it is possible to obtain a rubber material R having stable quality while preventing the compounding agent N charged into the kneading chamber 4a from being ejected.

In this embodiment, the load cell 13a is used as the sensor 13, but the sensor 13 is not limited to this. For example, instead of the load cell 13a, a temperature sensor 13 that sequentially acquires the temperature of the lower surface of the ram weight 8 can be used.

In this case, after the rubber material R is put into the kneading chamber 4a, the ram weight 8 is moved downward toward the lower limit position LP, and at that time, the temperature data of the lower surface of the ram weight 8 is sequentially acquired by the temperature sensor 13. Specifically, when the ram weight 8 is continuously moved downward, the lower surface of the ram weight 8 comes into contact with the rubber material R filled in the kneading chamber 4a. Since the temperature of the ram weight 8 and the rubber material R are different to some extent, the temperature acquired by the temperature sensor 13 changes abruptly in this contact state. The temperature data acquired by the temperature sensor 13 is input to the control unit 12.

Since the upper end position of the rubber material R is known by the change in the temperature data, the filling state of the rubber material R in the kneading chamber 4a is determined by the vertical position of the ram weight 8 and the change in the temperature data acquired by the temperature sensor 13. Can be grasped. That is, it can be determined that the upper end position of the rubber material R is located at the position of the lower surface of the ram weight 8 when the temperature data changes.

Then, based on the change in the temperature data, the control unit 12 determines whether or not the internal pressure of the kneading chamber 4a becomes larger than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP. Other steps are the same as in the previous embodiment.

As illustrated in FIG. 5, as the sensor 13, a distance sensor 13b for acquiring the vertical distance L from the ram weight 8 of the rubber material R charged into the kneading chamber 4a to the upper end position from the ram weight 8 is used. You can also.

Specifically, after the rubber material R is put into the kneading chamber 4a, the distance L between the distance sensor 13b and the upper end position of the rubber material R is acquired by the distance sensor 13b. The distance data acquired by the distance sensor 13b is input to the control unit 12. Since it can be determined that the upper end position of the rubber material R is located at a distance L below the position of the position sensor 13 at the time when the distance data is acquired, it is possible to grasp the filling state of the rubber material R in the kneading chamber 4a. it can.

Then, based on this distance data, the control unit 12 determines whether or not the internal pressure of the kneading chamber 4a becomes larger than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP. Other steps are the same as in the previous embodiment.

As illustrated in FIG. 6, as the sensor 13, a position sensor 13c that sequentially acquires the vertical position P of the ram weight 8 can also be used.

Specifically, after the rubber material R is put into the kneading chamber 4a, the ram weight 8 is moved downward toward the lower limit position LP, and at that time, the vertical position P of the ram weight 8 is sequentially acquired by the position sensor 13c. The position data acquired by the position sensor 13c is input to the control unit 12.

Specifically, when the ram weight 8 is continuously moved downward, the lower surface of the ram weight 8 comes into contact with the rubber material R filled in the kneading chamber 4a. When the lower surface of the ram weight 8 comes into contact with the rubber material R at a position above the lower limit position LP, the ram weight 8 becomes more difficult to move downward from the contacted position. Therefore, when the fluctuation of the position data becomes small at the position above the lower limit position LP, it is assumed that the upper end position of the rubber material R is located at the position of the lower surface of the ram weight 8 at the position P of the acquired position data. I can judge. Therefore, the position sensor 13c can grasp the filling state of the rubber material R in the kneading chamber 4c.

Then, the control unit 12 determines whether or not the internal pressure of the kneading chamber 4a becomes larger than the allowable pressure when the ram weight 8 is moved downward to the lower limit position LP based on the position data and the degree of fluctuation of the position data. To do. Other steps are the same as in the previous embodiment.

The above-described invention (various embodiments) can also be applied when a plurality of batches of a rubber material R are continuously kneaded. In this case, for example, the vertical movement control of the ram weight 8 in the kneading can be performed based on the vertical movement control of the ram weight 8 in the batch kneaded before the kneading.

When a plurality of batches of the rubber material R are continuously kneaded, the upper end position of the rubber material R filled in the kneading chamber 4a in each batch does not change significantly. Therefore, if the rubber material R of the batch kneaded one time before the kneading is properly kneaded without spouting of the compounding agent N, the ram weight 8 moves up and down as in the kneading in the batch. The rubber material R can be kneaded appropriately by controlling the above.

The above-described invention (various embodiments) can also be applied when the rubber material R having the same composition as the rubber material R to be kneaded this time is previously kneaded. In this case, for example, the vertical movement control of the ram weight 8 in the current kneading is performed based on the vertical movement control of the ram weight 8 in the previous kneading. If the rubber material R is properly kneaded by the previous kneading without spouting of the compounding agent N, the rubber material R is appropriately controlled by controlling the vertical movement of the ram weight 8 as in the previous kneading. Can be kneaded.

1 Kneading device 2 Sealed kneader 3 Rotor 3a Rotating shaft 3b Wings 4a Kneading chamber 4b Lamb weight chamber 5 Oil charging unit 6 Rubber charging unit 7 Hopper 8 Ram weight 8a Lifting mechanism 9 Mixing agent charging unit 10 Discharge door 11 Thermometer 12 Control unit 12a Power meter 13 Sensor 13a Load cell 13b Distance sensor 13c Position sensor G Raw material rubber N Non-vulcanized compounding agent R Rubber material

Claims (9)

In the kneading chamber of a closed-type kneader, a rubber material composed of a raw material rubber and a compounding agent is kneaded by arranging a ram weight above the kneading chamber and kneading the rubber material with a rotating rotor.
After the rubber material is put into the kneading chamber, the filling state of the rubber material in the kneading chamber is grasped from the data acquired from the sensor, and the vertical movement control of the ram weight is performed based on the data to control the vertical movement of the ram weight. When it is determined that the internal pressure of the kneading chamber becomes larger than the preset allowable pressure when the weight is moved downward to the lower limit position, the ram weight is stopped at a predetermined position above the lower limit position, and in this state. The rotor is rotated to pre-knead the rubber material, then the ram weight is moved to the lower limit position to stop, and in this state, the rotor is rotated to knead the rubber material. Kneading method of rubber material. A load cell attached to the ram weight is used as the sensor, the ram weight is moved downward toward the lower limit position, and the lower surface of the ram weight is moved from the rubber material charged into the kneading chamber at that time. The method for kneading a rubber material according to claim 1, wherein the load received is acquired by the load cell as the data. The rubber material according to claim 1, wherein a distance sensor attached to the ram weight is used as the sensor, and the distance to the upper end position of the rubber material put into the kneading chamber is acquired as the data by the distance sensor. Kneading method. The first aspect of claim 1, wherein a position sensor is used as the sensor, the ram weight is moved downward toward the lower limit position, and at that time, the vertical position of the ram weight is sequentially acquired by the position sensor as the data. Kneading method of rubber material. The first aspect of claim 1, wherein a temperature sensor is used as the sensor , the ram weight is moved downward toward the lower limit position, and at that time, the temperature of the lower surface of the ram weight is sequentially acquired by the temperature sensor as the data. How to knead the rubber material. The method for kneading a rubber material according to any one of claims 1 to 5, wherein the predetermined position is set at a position 1% to 10% higher than the outer diameter of the rotor with respect to the lower limit position. When a plurality of batches of the rubber material are kneaded continuously, a claim for controlling the vertical movement of the ram weight in the kneading based on the vertical movement control of the ram weight in the batch kneaded before the kneading. Item 8. The method for kneading a rubber material according to any one of Items 1 to 6. When a rubber material having the same composition as the rubber material to be kneaded this time is previously kneaded, the vertical movement control of the ram weight in the current kneading is based on the vertical movement control of the ram weight in the previous kneading. The method for kneading a rubber material according to any one of claims 1 to 6. A rubber material composed of a raw material rubber and a compounding agent, which has a rotor installed in the kneading chamber and a ram weight which is arranged above the kneading chamber and moves up and down, is obtained by rotating the rotor. In a rubber material kneading device equipped with a closed kneader that kneads in a kneading room,
It has a sensor for acquiring data for grasping the filling state of the rubber material in the kneading chamber, and a control unit for inputting the acquired data.
After the rubber material is put into the kneading chamber, the control unit controls the vertical movement of the ram weight based on the data, and when the ram weight is moved downward to the lower limit position, the internal pressure of the kneading chamber is increased. When the control unit determines that the allowable pressure exceeds a preset allowable pressure, the ram weight is stopped at a predetermined position above the lower limit position, and in this state, the rotor is rotated to pre-knead the rubber material. After that, the rubber material kneading device is characterized in that the ram weight is moved to the lower limit position and stopped, and the rotor is rotated in this state to knead the rubber material.

Images