JP6933047B2 - Kneading method and equipment for rubber materials - Google Patents

Description

The present invention relates to a rubber material kneading method and an apparatus, and more particularly to a rubber material kneading method and an apparatus capable of performing a plurality of kneading steps in a closed kneader evenly and more efficiently. It is a thing.

When manufacturing rubber products such as tires, various rubber members are used. A closed type kneader (so-called Banbury mixer) is known as a facility for kneading a rubber material that is a material for a rubber member. The closed kneader has a set of rotors installed in the kneading chamber. The closed kneader has the same specifications in which the rotors are paired with each other, and generally has a structure in which the rotors are rotationally driven by one drive motor.

In the closed kneader, the rubber kneading step, the compounding agent uptake step, and the uniform dispersion step are mainly performed. In the rubber kneading stage, the raw rubber and oil are kneaded. Next, in the compounding agent uptake stage, the raw rubber and the non-vulcanized compounding agent are kneaded. Then, in the uniform dispersion step, the compounding agent is uniformly dispersed over the entire raw rubber. Since the purpose of each stage is different, the optimum kneading conditions are also different. Therefore, conventionally, the rotation speed of the rotor is changed for each kneading step, or the temperature condition is adjusted, but it is difficult to set the kneading condition suitable for each step.

A kneading device has been proposed in which a set of rotors of a closed kneader is rotationally driven by separate independent motors (see Patent Document 1). According to this kneading device, each motor can be independently controlled to rotate and drive each rotor, so that it becomes easy to set kneading conditions suitable for each kneading stage. However, it is difficult to perform each stage evenly and efficiently because it may not be possible to set kneading conditions suitable for each stage simply by changing the rotation speed and phase of each rotor.

Japanese Unexamined Patent Publication No. 10-71613

An object of the present invention is to provide a method and an apparatus for kneading a rubber material, which makes it possible to perform a plurality of kneading steps in a closed kneader evenly and more efficiently.

In order to achieve the above object, in the method for kneading a rubber material of the present invention, a kneaded product containing a raw material rubber and a compounding agent is kneaded using a closed kneader having a kneading chamber in which a set of rotors is installed. In the method of kneading the rubber material, the set of rotors is divided into at least one of the stirring blades of each rotor in the longitudinal direction, so that only the number and length of the stirring blades of the respective rotors are different. so, the other specifications in the same, and in different shapes, and, for each of which is an intermediate position of the rotation axis to each other of the rotor the rotation axis extending in the axial direction of each of the rotor By forming the asymmetric shape, each of the rotors has a different shape that does not form a pair, and the materials of the kneaded product are sequentially charged into the kneading chamber, and the pair of rotors are rotationally driven to knead the mixture. And.
Another method of kneading the rubber material of the present invention is to knead the kneaded product containing the raw material rubber and the compounding agent by using a closed kneader having a kneading chamber in which a set of rotors is installed. In the method, only one of the number of stirring blades of each of the rotors, the inclination angle of the stirring blades with respect to the center line, and the thickness of the stirring blades of the set of rotors is used among the rotors. With respect to the center line extending in the axial direction of the rotating shaft, which is an intermediate position between the rotating shafts of the respective rotors, and having the same other specifications and different shapes. By making the rotors asymmetrical, each of the rotors has a different shape that does not pair, and the materials of the kneaded material are sequentially put into the kneading chamber, and the pair of rotors are rotationally driven to knead. It is characterized by.

The rubber material kneading device of the present invention rotates and drives a kneading chamber in which a kneaded product containing a raw material rubber and a compounding agent is charged, a set of rotors built in the kneading chamber, and a pair of rotors. In a kneading device having a drive motor and a closed kneader including a control unit for controlling the drive motor, the set of rotors is divided into at least one of the stirring blades of each rotor in the longitudinal direction. by that, unlike only the number and length of the stirring blades in each of the rotor to each other, are the other specifications are the same, they become different shapes, and the intermediate axis of rotation each other of each rotor By making each rotor asymmetrical with respect to the center line extending in the axial direction of the rotation axis, which is the position, each rotor is set to a different shape that is not paired, and the kneading is performed. The material of the kneaded product, which is sequentially charged into the chamber, is kneaded by rotating the pair of rotors.
Another rubber material kneading device of the present invention rotates a kneading chamber in which a kneaded product containing a raw material rubber and a compounding agent is charged, a set of rotors built in the kneading chamber, and a pair of rotors. In a kneading device having a closed kneader including a drive motor to be driven and a control unit for controlling the drive motor, the set of rotors has the number of stirring blades of each rotor, and the number of stirring blades of the stirring blades. Only one of the inclination angle with respect to the center line and the thickness of the stirring blade is different between the rotors, the other specifications are the same, the shapes are different from each other, and the rotors are different from each other. By making each rotor asymmetrical with respect to the center line extending in the axial direction of the rotating shaft, which is an intermediate position between the rotating shafts, each rotor is set to a different shape that is not paired. The material of the kneaded product, which is sequentially charged into the kneading chamber, is kneaded by rotating the pair of rotors.

According to the present invention, a set of rotors provided in a closed kneader has a different shape from each other, and an intermediate position between the rotation axes of the respective rotors extends with respect to a center line extending in the axial direction of the rotation axes. By making the shape asymmetric, each rotor is set to a different shape that does not pair, so the shearing force applied to the kneaded product is compared to the case of using a set of rotors with a conventional paired shape. And the variation of the flow direction of the kneaded material can be increased. Along with this, when kneading the materials sequentially put into the kneading chamber, it becomes easy to realize kneading conditions suitable for each kneading stage. Therefore, it becomes possible to perform a plurality of kneading steps in a closed kneader evenly and more efficiently.

It is explanatory drawing which illustrates the kneading apparatus of this invention in the vertical cross-sectional view of the closed type kneader. It is explanatory drawing which illustrates the kneading apparatus of FIG. 1 in a plan view. It is explanatory drawing which schematically exemplifies a set of rotors of FIG. 1 in a plan view. It is a graph which illustrates the rotation speed of a rotor in the kneading process of a rubber material, the instantaneous electric power required for the rotation drive, and the time-dependent change of the temperature of a kneaded product. It is explanatory drawing which illustrates the state which the kneaded material is kneaded by the kneading apparatus of FIG. It is explanatory drawing which shows the deformation example of a set of rotors schematically in a plan view. It is explanatory drawing which shows the deformation example of a set of rotors schematically in a plan view. It is explanatory drawing which shows the deformation example of a set of rotors schematically in a plan view. It is explanatory drawing which schematically exemplifies a set of conventional rotors in a plan view.

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 to 3 kneads the kneaded product R containing the raw material rubber G and the compounding agent N. By this kneading step, the compounding agent N is evenly dispersed in the raw rubber G to produce an unvulcanized rubber material having an appropriate viscosity.

As the raw material rubber G and the compounding agent N, appropriate materials are selected according to the type (characteristics) of the rubber material to be produced. 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, a filler such as silica and silane coupling agent, carbon black, and a non-vulcanizing compounding agent N such as zinc oxide and stearic acid are appropriately selected and used. Oil is also used as the compounding agent N.

The kneading device 1 has a closed kneading machine 1a. The closed type kneader 1a includes a kneading chamber 5a, a set of rotors 2 (2A, 2B) internally installed in the kneading chamber 5a, and a drive motor 3 (3A, 3B) for rotationally driving the respective rotors 2A and 2B. And a control unit 12 for controlling the drive motor 3. In this embodiment, the kneading device 1 further includes a temperature sensor 13. The temperature sensor 13 is provided in the kneading chamber 5a with its tip exposed. The temperature sensor 13 sequentially detects the temperature of the kneaded product R kneaded in the kneading chamber 5a, and the detection data is input to the control unit 12.

An oil charging section 7 is provided on the side of the kneading chamber 5a, and a discharge door 11 that opens and closes is provided on the bottom surface. A ram chamber 5b is connected above the kneading chamber 5a, and a ram 6 that moves up and down to adjust the pressure (ram pressure) in the kneading chamber 5a is arranged inside the ram chamber 5b. On the side of the ram chamber 5b, a rubber charging section 8 into which the raw material rubber G is charged and a compounding agent charging section 10 in which the non-vulcanizing compounding agent N is charged from the hopper 9 are provided.

A power meter 12a is attached to the control unit 12. The instantaneous power P required for rotationally driving the rotor 2 is sequentially detected by the power meter 12a, and the detection data is input to the control unit 12. The control unit 12 calculates the integrated electric power amount obtained by integrating the instantaneous power, and can grasp the electric power amount (load acting on the rotor 2) required for rotationally driving the rotor 2 in an arbitrary kneading period. The rotation speed (rotation speed) and ram pressure of the rotor 2 are input to the control unit 12, and the rotation speed and ram pressure (up and down movement of the ram) of the rotor 2 are controlled by the control unit 12.

Each rotor 2 is connected to the drive motor 3 via a transmission 4. In this embodiment, the rotors 2A and 2B are provided with independent drive motors 3A and 3B, respectively. Therefore, it is easy to drive the rotors 2A and 2B independently at a desired rotation speed. Along with this, the operation of changing the rotation speed ratios of the rotors 2A and 2B can be quickly performed.

Each rotor 2 has a rotating shaft 2c and a stirring blade 2d projecting from the peripheral surface of the rotating shaft 2c. In the figure, the center line CL extending in the axial direction of the rotating shaft 2c at the intermediate position between the rotating shafts 2c arranged in parallel is shown by a chain line. The specifications of each rotor 2 (outer diameter of rotating shaft 2c, peripheral surface shape, number of stirring blades 2d, thickness t, length L, outer diameter, inclination angle a (≦ 90 degrees) with respect to center line CL, etc.) , Is appropriately set depending on the type of kneaded product R and the like.

In FIG. 1, the stirring blades 2d of the rotors 2A and 2B are out of phase, but in FIG. 3, the phases are matched in order to make it easier to compare the stirring blades 2d. .. 6 to 9 are also shown in a state where the phases of the stirring blades 2d of the rotors 2A and 2B are matched.

One of the features of the present invention is that a set of rotors 2 have different shapes and asymmetric shapes with respect to the center line CL. That is, the rotors 2A and 2B are set to different shapes that are not paired. For example, at least one of the number of stirring blades 2d possessed by the rotors 2A and 2B, the inclination angle a of the stirring blades 2d with respect to the center line CL, the thickness t of the stirring blades 2d, and the length L of the stirring blades 2d, respectively. By making the rotors 2A and 2B different from each other, the rotors 2A and 2B have different shapes that are not paired with each other.

As illustrated in FIG. 9, the conventional set of rotors 14 have the same shape paired with each other. The set of rotors 14 illustrated in FIG. 9A has the same shape except that the directions of the stirring blades 14b are different from each other, and the rotors 14 have a symmetrical shape with respect to the center line CL. In the set of rotors 14 illustrated in FIG. 9B, both the rotating shaft 14a and the stirring blade 14b have the same shape. The set of rotors 2A and 2B of the present invention has specifications different from those of the conventional set of rotors 14.

In this embodiment, as illustrated in FIG. 3, the number and length L of the stirring blades 2d of the rotors 2A and 2B are different from each other. That is, with respect to the length L1 of the stirring blade 2d of one rotor 2A, the stirring blade 2d of the other rotor 2B is divided in the length direction to have a shorter length L2. Along with this, the number of stirring blades 2d of the other rotor 2B has increased. Other specifications of the rotors 2A and 2B are the same.

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

As illustrated in FIG. 4, the kneading step is composed of a rubber kneading step (S1), a compounding agent uptake step (S2), and a uniform dispersion step (S3). FIG. 4 illustrates time-dependent data of the rotation speed r of the rotor 2 in the kneading step, the instantaneous power P required for the rotation drive, and the temperature T of the kneaded product R. The rotation speed r in FIG. 4 is an average value of the rotation speeds of the rotors 2A and 2B, respectively.

In the rubber kneading step, as illustrated in FIG. 1, in a state where the ram 6 is held at the standby position at the upper end of the ram chamber 5b, a preset predetermined amount of raw rubber G is kneaded through the rubber charging section 8. It is put into the chamber 5a. After that, the ram 6 is moved downward to the lower end of the ram chamber 5b. In this state, the rotor 2 is rotationally driven to knead the raw material rubber G and the oil while charging the oil into the kneading chamber 5a through the oil charging section 7. At this stage, the instantaneous power P indicating the load of the rotor 2 is relatively small, and the temperature T of the kneaded product R gradually decreases.

After the rubber kneading stage is completed, the process proceeds to the compounding agent uptake stage. In the compounding agent uptake stage, the ram 6 is moved to the standby position at the upper end of the ram chamber 5b, and a predetermined amount of compounding agent N (filler or the like) of a preset type is transferred from the hopper 9 through the compounding agent charging unit 10. It is put into the kneading chamber 5a. After that, the ram 6 is moved downward to the lower end of the ram chamber 5b. In this state, the rotor 2 is rotationally driven to knead the kneaded product R as illustrated in FIG.

In the compounding agent uptake stage, the compounding agent N placed on the raw rubber G kneaded with rubber is largely stirred to gradually form a small mass of rubber. The small rubber mass then gradually grows into a mass at the end. In the compounding agent uptake stage, the ram 6 is raised several times to the upper end of the ram chamber 5b, and the rotor 2 is rotated to invert the ram so that the kneaded product R is turned upside down. At this stage, the temperature T of the kneaded product R gradually rises.

When the carbon uptake stage is completed, the process proceeds to the uniform dispersion stage. At this stage, the compounding agent N is uniformly dispersed over the entire raw material rubber G. At this stage, the instantaneous power P is initially large, but gradually decreases. The temperature T of the kneaded product R is maintained substantially constant within a predetermined temperature range. That is, at this stage, the rotation speed of the rotor 2 is controlled by the control unit 12 based on the detection data of the temperature T of the kneaded product R sequentially detected by the temperature sensor 13, and the temperature T of the kneaded product R is set to a predetermined temperature. Keep in range and knead.

After the completion of the uniform dispersion step, the unvulcanized rubber material produced by kneading the kneaded product R is discharged to the outside of the closed kneader 1a through the opened discharge door 11. In the next step, the discharged rubber material is kneaded with a vulcanization-based compounding agent such as sulfur and a vulcanization accelerator in a predetermined ratio. The time-dependent data of the rotation speed r, the instantaneous power P, and the temperature T of the kneaded product R of the rotor 2 illustrated in FIG. 4 differ depending on the type of material constituting the kneaded product R and the like.

At each stage of the kneading process, the rotors 2A and 2B are rotationally driven at an appropriate rotation speed, but in the present invention, the rotors 2A and 2B have different shapes. Therefore, the kneaded product R is kneaded by rotors 2A and 2B having different shapes. Further, the kneaded product R can be kneaded evenly by both rotors 2, or can be kneaded by biasing the kneaded product R to one of the rotors 2.

Therefore, as compared with the case of using a set of rotors 14 having a paired shape as illustrated in FIG. 9, the shearing force applied to the kneaded product R and the flow direction of the kneaded product R (stirring effect). Variations can be increased. Therefore, when kneading the materials sequentially put into the kneading chamber 5a, it becomes easy to realize kneading conditions suitable for each kneading step (S1, S2, S3). Along with this, each kneading step can be performed evenly and more efficiently.

In the rotor 2 illustrated in FIG. 3, one rotor 2A is easier to disperse the material of the kneaded product R more evenly than the other rotor 2B. Therefore, in the uniform dispersion step in which the compounding agent N needs to be more dispersed in the raw material rubber G, the kneaded product R is positively flowed to one rotor 2A side to perform kneading. For example, the rotation speed of one rotor 2A is made higher than that of the other rotor 2B, and the kneaded product R is biased toward one rotor 2A.

The other rotor 2B is easier to apply a large shearing force to the kneaded product R than the one rotor 2A. Therefore, in the kneading step or the compound taking-in step in which it is necessary to apply a larger shearing force to the kneaded product R, the kneaded product R is positively flowed to the other rotor 2B side to perform kneading. For example, the rotation speed of the other rotor 2B is made higher than that of the one rotor 2A, and the kneaded product R is biased toward the other rotor 2B.

The rotors 2A and 2B are not limited to the shapes illustrated in FIG. 3, but may also have the shapes illustrated in FIGS. 6, 7, and 8. In FIG. 6, the number of stirring blades 2d of the rotors 2A and 2B is different. That is, one rotor 2A has a larger number of stirring blades 2d than the other rotor 2B. Along with this, in one rotor 2A, the interval (arrangement pitch) of the stirring blades 2d is narrowed. Other specifications of the rotors 2A and 2B are the same.

In the rotor 2 illustrated in FIG. 6, the other rotor 2B is easier to disperse the material of the kneaded product R more evenly than the one rotor 2A. One rotor 2A is compared with the other rotor 2B, has easily impart large shearing force to the kneaded product R. Therefore, as described above, the kneaded product R may be kneaded by appropriately using the respective rotors 2A and 2B according to each kneading step.

In FIG. 7, the inclination angles a of the stirring blades 2d of the rotors 2A and 2B are different. That is, the inclination angle a1 of one rotor 2A is smaller than the inclination angle a2 of the other rotor 2B. Other specifications of the rotors 2A and 2B are the same.

In the rotor 2 illustrated in FIG. 7, one rotor 2A is easier to disperse the material of the kneaded product R more evenly than the other rotor 2B. Other rotor 2B is compared to the one rotor 2A, which is easy to impart a large shearing force to the kneaded product R. Therefore, as described above, the kneaded product R may be kneaded by appropriately using the respective rotors 2A and 2B according to each kneading step.

In FIG. 8, the thickness t of the stirring blades 2d of the rotors 2A and 2B is different. That is, the thickness t1 of one rotor 2A is smaller than the thickness t2 of the other rotor 2B. Other specifications of the rotors 2A and 2B are the same.

In the rotor 2 illustrated in FIG. 8, one rotor 2A is easier to disperse the material of the kneaded product R more evenly than the other rotor 2B. The other rotor 2B is easier to apply a large shearing force to the kneaded product R than the one rotor 2A. Therefore, as described above, the kneaded product R may be kneaded by appropriately using the respective rotors 2A and 2B according to each kneading step.

The rotation speeds (rotational speeds) of the rotors 2A and 2B can be different for each kneading stage or in the middle of each kneading stage.

Unlike the above embodiment, one drive motor 3 may be used to drive the rotors 2A and 2B to rotate. In this configuration, the transmission 4 drives the rotors 2A and 2B to rotate at appropriate rotation speeds. By changing the gear of the transmission 4, the rotation speed ratios of the rotors 2A and 2B can be changed.

By making the rotors 2A and 2B different from each other, the magnitude of the load received by the rotors 2A and 2B is likely to be different. Therefore, if the rotors 2A and 2B are made of the same material and have the same surface treatment, a large difference in the degree of deterioration may occur over time. Therefore, at least one of the material and the surface treatment of the rotors 2A and 2B can be different. For example, the rotor 2 that receives a relatively large load may be configured such that a material having higher durability (proof stress, etc.) is used, or the thickness of the surface treatment layer such as plating is increased.

1 Kneading device 1a Sealed kneader 2 (2A, 2B) Rotor 2c Rotating shaft 2d Stirring blade 3 (3A, 3B) Drive motor 4 Transmission 5a Kneading chamber 5b Ram chamber 6 Ram 7 Oil charging section 8 Rubber charging section 9 Hopper 10 Blending agent input unit 11 Discharge door 12 Control unit 12a Power meter 13 Temperature sensor 14 Conventional rotor 14a Rotating shaft 14b Stirring blade G Raw material rubber N Blending agent R Kneaded product

Claims (8)

In a method of kneading a rubber material in which a kneaded product containing a raw material rubber and a compounding agent is kneaded using a closed kneader having a kneading chamber in which a set of rotors is installed.
By dividing at least one of the stirring blades of each of the rotors in the longitudinal direction into the set of rotors, only the number and length of the stirring blades of each of the rotors are different, and the other specifications are the same. a manner, the different shapes, and, with respect to the center line extending in the axial direction of the rotary shaft is an intermediate position of the rotation axis to each other of the respective rotors, each of the rotor by asymmetrical, A method for kneading a rubber material, which comprises forming each of the rotors into different shapes that do not form a pair, sequentially charging the materials of the kneaded material into the kneading chamber, and rotating the pair of rotors to knead the materials. .. In a method of kneading a rubber material in which a kneaded product containing a raw material rubber and a compounding agent is kneaded using a closed kneader having a kneading chamber in which a set of rotors is installed.
Only one of the number of stirring blades of each of the rotors, the inclination angle of the stirring blades with respect to the center line, and the thickness of the stirring blades of the set of rotors is made different between the rotors. , the other specifications in the same, and in different shapes, and, for each of the rotor of the rotary shaft to each other the rotation axis extending in the axial direction of an intermediate position of each of the rotor asymmetry By forming the shape, each of the rotors has a different shape that does not form a pair, and the materials of the kneaded product are sequentially put into the kneading chamber and kneaded by rotationally driving the pair of rotors. How to knead the rubber material. The method for kneading a rubber material according to claim 1 or 2, wherein the rotation speed ratio of each of the rotors is changed on the way. The method for kneading a rubber material according to any one of claims 1 to 3, wherein each rotor is rotationally driven by a drive motor independent of each other. A kneading chamber in which a kneaded product containing raw rubber and a compounding agent is charged, a set of rotors installed in the kneading chamber, a drive motor for rotating the pair of rotors, and a drive motor for controlling the drive motor. In a kneading device having a closed type kneader equipped with a control unit,
Since at least one of the stirring blades of each of the rotors is divided in the longitudinal direction in the set of rotors, only the number and length of the stirring blades differ between the rotors, and other specifications are different. They are the same, they become different shapes, and, with respect to the center line extending in the axial direction of the rotary shaft is an intermediate position of the rotation axis to each other of the respective rotors, each of the rotor asymmetrically The rotors are set to different shapes that are not paired with each other, and the materials of the kneaded material sequentially charged into the kneading chamber are kneaded by rotationally driving the pair of rotors. A rubber material kneading device characterized by having a structure. A kneading chamber in which a kneaded product containing raw rubber and a compounding agent is charged, a set of rotors installed in the kneading chamber, a drive motor for rotating the pair of rotors, and a drive motor for controlling the drive motor. In a kneading device having a closed type kneader equipped with a control unit,
Only one of the number of stirring blades of each of the rotors, the inclination angle of the stirring blades with respect to the center line, and the thickness of the stirring blades of the set of rotors is different between the rotors. The other rotors have the same specifications, have different shapes from each other , and have a center line extending in the axial direction of the rotating shafts, which is an intermediate position between the rotating shafts of the respective rotors. The rotors are set to different shapes that are not paired with each other by making the rotors asymmetrical, and the material of the kneaded material sequentially charged into the kneading chamber rotates the pair of rotors. A rubber material kneading device characterized in that it is kneaded. The rubber material kneading device according to claim 5 or 6, wherein the rotation speed ratio of each rotor is changed on the way by the control unit. The rubber material kneading device according to any one of claims 5 to 7, wherein the drive motor is provided independently for each of the rotors.

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