JP2019093584A - Method and apparatus for kneading rubber material - Google Patents

Abstract

To provide a method and an apparatus for kneading a rubber material, in which a powdery compounding agent can be dispersed more evenly in raw material rubber without being excessively compressed, by using a hermetically sealed type kneading machine.SOLUTION: A method for kneading a rubber material includes the steps of: inputting phase data according to rotation of one set of rotors 3 into a control part 12; successively calculating an area S of a gap 5c between the set of rotors 3 in a top surface view, on the basis of the phase data using the control part 12; and kneading a kneading object R containing a raw material rubber G and a powdery compounding agent N inputted to a kneading chamber 5 by using the rotating set of rotors 3, while the control part 12 adjusts ram pressure acting on a ram 6 detected by a pressure sensor 14, on the basis of size of the area S of the successively calculated gap 5c.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method and an apparatus for kneading a rubber material, and more specifically, a rubber which can disperse a powdery compounding agent more uniformly to a raw rubber without excessive compression using a closed-type kneader The present invention relates to a method and apparatus for kneading materials.

  In manufacturing rubber products such as tires, various rubber members are used. A closed-type kneader (so-called Banbury mixer) is known as an apparatus for kneading a rubber material to be a material of a rubber member. The closed-type kneader has a specification provided with a meshing type rotor in which a pair of rotors are arranged so as to mesh with each other in a kneading chamber (see, for example, Patent Document 1).

  The raw material rubber and the powdery compounding agent introduced into the kneading chamber are kneaded by the rotating rotors while being pressed downward by the ram in a state of closing the upper end opening of the kneading chamber. In the case of meshed rotors, the phase due to the rotation of a pair of rotors causes relatively large fluctuations in the clearance between the rotors and the volume of the receiving space above the rotors. Therefore, if the ram pressure is increased when the gap between the rotors narrows, the powdery compounding agent may be excessively compressed between the rotors. Along with this, the powdery compounding agent solidifies firmly to become a non-breakable mass, and there arises a problem that the raw material rubber can not be uniformly dispersed. Even if they are not meshed rotors, the phase due to the rotation of a pair of rotors causes similar problems if the gap between the rotors and the volume of the receiving space above each other are relatively large.

Unexamined-Japanese-Patent No. 2003-277861

  An object of the present invention is to provide a kneading method and apparatus of a rubber material which can be uniformly dispersed in a raw rubber without excessively compressing a powdery compounding agent by using a closed type kneader. is there.

  A method of kneading a rubber material according to the present invention for achieving the above object comprises a set of a rotor disposed inside a kneading chamber, a kneaded material containing a raw material rubber and a powdery compounding agent, and In a kneading method of a rubber material to be kneaded using a closed type kneader including a ram capable of vertically moving upward and closing an upper end opening of the kneading chamber, phase data by rotation of the pair of rotors is The area of the gap between the pair of rotors is sequentially calculated by the controller based on the phase data, and the area of the gap is sequentially calculated based on the phase data, and the space is calculated based on the size of the sequentially calculated gap. It is characterized by knead | mixing with a set of said rotor which rotates the said kneaded material thrown into the said kneading chamber, adjusting the ram pressure which acts on a ram by the said control part.

  The apparatus for kneading a rubber material according to the present invention comprises: a kneading chamber into which a kneaded material containing raw material rubber and a powdery compounding agent is introduced; a pair of rotors disposed inside the kneading chamber; In a rubber material kneading apparatus having a closed type kneader including a ram capable of vertically moving upward and closing an upper end opening of the kneading chamber, phase data by rotation of the pair of rotors is input The controller has a pressure sensor for detecting a ram pressure acting on the ram, and the area of the gap between the pair of rotors in top view is sequentially calculated by the controller based on the phase data. The set of rotating the kneaded material introduced into the kneading chamber while adjusting the ram pressure detected by the pressure sensor by the control unit based on the size of the sequentially calculated clearance area Kneaded by the rotor of Characterized in that the arrangement.

  According to the present invention, the control unit sequentially calculates the area of the gap between the pair of rotors in top view based on the phase data of the rotation of the pair of rotors, and the size of the sequentially calculated gap area The ram pressure can be properly adjusted based on the Thereby, when the area of the gap is small, the ram pressure applied to the kneaded material can be reduced to allow the kneaded material to pass between the rotors. Therefore, the powdery compounding agent is not excessively compressed between the narrowed rotors, and it is possible to suppress the formation of a firmly solidified lump. Along with this, it becomes advantageous to disperse the powdered compounding agent more uniformly in the raw rubber.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which illustrates the closed type kneader by the longitudinal cross-sectional view of the kneading apparatus of this invention. It is explanatory drawing which expands and illustrates the inside of the kneading chamber of FIG. It is explanatory drawing which illustrates one set of rotors of FIG. 2 by top view. FIG. 2 is a graph illustrating the phase data of a set of rotors of FIG. It is explanatory drawing which illustrates the state which knead | mixes a kneaded material by the kneading apparatus of FIG.

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

  The rubber material kneading apparatus 1 (hereinafter referred to as the kneading apparatus 1) of the present invention illustrated in FIGS. 1 to 3 knead a kneaded material R containing a raw material rubber G and a compounding agent N. In this kneading step, the compounding agent N is uniformly dispersed in the raw rubber G to produce an unvulcanized rubber material having an appropriate viscosity.

  The raw material rubber G and the compounding agent N are appropriately selected depending on the type (characteristics) of the rubber material to be produced. 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), nitrile rubber (acrylonitrile rubber, Hydrogenated nitrile rubber), ethylene propylene diene rubber and the like can be exemplified. These are used individually by 1 type or in combination of 2 or more types. As the compounding agent N, non-vulcanized compounding agents N such as silica and a silane coupling agent, fillers such as carbon black, zinc oxide and stearic acid are appropriately selected and used. An oil is also used as compounding agent N.

  The kneading apparatus 1 has a closed type kneading machine 2. The closed-type kneader 2 includes a kneading chamber 5 into which a kneaded material R containing raw rubber G and a compounding agent N is charged, a pair of rotors 3 disposed inside the kneading chamber 5, and an upper end of the kneading chamber 5. A ram 6 capable of closing the opening 5a, a control unit 12, and a pressure sensor 14 are provided. The control unit 12 receives phase data by rotation of the rotor 3 and data detected by the pressure sensor 14. The control unit 12 controls the rotational drive of the rotor 3.

  An oil inlet 7 is provided on the side of the kneading chamber 5, and an outlet door 11 is provided on the bottom. A ram chamber 6 a is connected to the upper end opening 5 a of the kneading chamber 5 and extends upward. The ram 6 moves up and down inside the ram chamber 6 a to apply pressure (ram pressure P) to the kneaded material R in the kneading chamber 5. The ram 6 can close the upper end opening 5a of the kneading chamber 5 by moving downward. On the side portion of the ram chamber 6a, a feeding mechanism 8 having a conveying conveyor and the like, and a combination agent feeding unit 10 for feeding the non-vulcanized compounding agent N from the hopper 9 are provided. The feeding mechanism 8 is controlled by the control unit 12 and feeds the raw material rubber G into the kneading chamber 5.

  The kneading apparatus 1 of this embodiment further has a temperature sensor 13. The temperature sensor 13 is provided in the kneading chamber 5 with its tip exposed. The temperature sensor 13 sequentially detects the temperature of the kneaded material R (raw rubber G) being kneaded in the kneading chamber 5, and the detection data is input to the control unit 12.

  The pressure sensor 14 installed in the ram 6 sequentially detects the pressure acting on the ram 6 while kneading the kneaded material R (raw rubber G) in the kneading chamber 5, and the detected data is sent to the control unit 12. It is input. Since the pressure acting on the kneaded material R in the kneading chamber 5 acts on the ram 6 as a reaction, the detection data by the pressure sensor 14 is the pressure applied to the kneaded material R in the kneading chamber 5.

  A power meter 12 a is attached to the control unit 12. The instantaneous power P required for the rotational driving of the rotor 3 is sequentially detected by the power meter 12 a, and the detection data is input to the control unit 12. The control unit 12 calculates the integrated power amount obtained by integrating the instantaneous power, and can grasp the power amount (load acting on the rotor 3) required for the rotational drive of the rotor 3 in an arbitrary kneading period. The rotational speed (rotational speed) of the rotor 3 and the like are also input to the control unit 12, and the rotational speed of the rotor 3 and the ram pressure P (vertical movement of the ram 6) are controlled by the control unit 12.

  Each of the rotors 3 has a rotating shaft 4a disposed in parallel with each other, and a stirring blade 4b provided so as to protrude from the outer peripheral surface of the rotating shaft 4a. A so-called meshing type rotor 3 is disposed so that the outer peripheral surfaces of the rotors 3 mesh with each other. The specifications (the shape and the like of the outer peripheral surface) of the outer peripheral surface of each rotor 3 are appropriately set according to the type of the kneaded material R and the like.

  The above-mentioned phase data is data of the rotation angle (the rotated position) of each rotor 3. When each rotor 3 makes one rotation (360 ° rotation), as illustrated in FIG. 4, the volume V of the receiving space 5 b in the upper part between the rotors 3 (curve V shown by a solid line) and the clearance in top view between the rotors 3 The area S of 5c (curve S shown by a broken line) fluctuates. The fluctuation of the volume V of the receiving space 5 b and the area S of the gap 5 c is repeated for each rotation of the respective rotors 3.

  The receiving space 5 b is located above the rotor 3 and is a space in which the kneaded material R introduced into the kneading chamber 5 is first disposed. As illustrated in FIG. 2, a space between the rotors 3 and surrounded by the upper end opening 5 a of the kneading chamber 5 and the outer peripheral surface of each of the rotors 3 is a receiving space 5 b.

  The area S of the gap 5c between the rotors 3 in a top view is the area of the top view between the outer peripheral surfaces of the respective rotors 3A and 2B in the kneading chamber 5. In FIG. 3, the area S of the gap 5c is illustrated by the hatched portion.

  In this embodiment, as illustrated in FIG. 4, the volume V of the receiving space 5b becomes the minimum value Vn (minimum volume) when the rotor 3 rotates 90 ° from a certain position, and the receiving space 5b rotates 180 °. Becomes the maximum value Vx (maximum volume). The area S of the gap 5c becomes the maximum value Sx (maximum area) when the respective rotors 3 rotate 30 degrees from the position, and becomes the minimum value Sn (minimum area) when the rotor 3 rotates 110 degrees. When the volume V of the receiving space 5b reaches the maximum value Vx due to the rotation of the respective rotors 3, the area S of the gap 5c is in an increasing state and then reaches the maximum area. Such fluctuation of the volume V and the area S is repeated every half rotation (180 ° rotation) of each rotor 3. The variation of the volume V of the receiving space 5b and the area S of the gap 5c varies depending on the specifications of the outer peripheral surface of the respective rotors 3 and is not limited to that illustrated in FIG. The present invention can also be applied to cases where the volume V and the area S change in various ways other than that illustrated in FIG.

  Since the specifications (the outer peripheral surface shape and the like) of each rotor 3 are known, if the phase of each rotor 3 is known, it is possible to grasp the volume V of the receiving space 5b and the area S of the gap 5c at any time. Therefore, in the present invention, phase data by rotation of a set of rotors 3 is input to the control unit 12, and the control unit 12 sequentially calculates the area S of the gap 5c based on the input phase data. Further, in this embodiment, the volume V of the receiving space 5b is sequentially calculated by the control unit 12 based on the input phase data.

  The means for acquiring phase data is not particularly limited. For example, the rotational speed (rotational position) of the rotation shaft 4a of each rotor 3 can be detected by a known sensor or the like, and phase data can be obtained (calculated) based on the detection data.

  Hereinafter, an example of the kneading method of the rubber material of the present invention will be described.

  As illustrated in FIG. 1, when the raw material rubber G and the powdery compounding agent N are put into the kneading chamber 5 and the kneaded material R is kneaded, the ram 6 is held at the standby position at the upper end of the ram chamber 6a. In the above state, a predetermined amount of raw material rubber G set in advance is introduced into the kneading chamber 5 using the introduction mechanism 8. A predetermined amount of compounding agent N (filler and the like) of a predetermined type is introduced from the hopper 9 into the kneading chamber 5 through the compounding agent introduction unit 10. Further, the oil is appropriately introduced into the kneading chamber 5 through the oil introduction unit 7.

  Thereafter, as illustrated in FIG. 5, the ram 6 is moved to the lower side of the ram chamber 6a to close the upper end opening 5a. In this state, each rotor 3 is rotationally driven to adjust the upper and lower positions of the ram 6, the number of rotations of the rotor 3, etc., and detect the temperature of the kneaded material R, the ram pressure P and the electric power while detecting the kneaded material R Knead. As a result, the compounding agent N is uniformly dispersed in the raw rubber G to produce an unvulcanized rubber material having an appropriate viscosity. The unvulcanized rubber material produced is discharged from the open discharge door 11 to the outside of the internal mixer 2. In the next step, the discharged rubber material is compounded and kneaded at a predetermined ratio with a vulcanizing compounding agent such as sulfur and a vulcanization accelerator.

  In the present invention, when kneading the kneaded material R, phase data of the rotating pair of rotors 3 is sequentially detected and input to the control unit 12. The control unit 12 sequentially calculates the area S of the gap 5c in top view between the rotors 3 based on the input phase data. The ram pressure P detected by the pressure sensor 14 is sequentially input to the control unit 12. Therefore, the kneaded material R is kneaded while adjusting the magnitude of the ram pressure P (the pressure detected by the pressure sensor 14) acting on the ram 6 by the control unit 12 based on the size of the area S of the clearance 5c sequentially calculated. .

  The variation of the adjusted ram pressure P is illustrated in FIG. As illustrated in FIG. 4, when the area S of the gap 5c calculated sequentially is in an increasing state (the curve S in FIG. 4 is in the upper right), the ram 6 is moved downward to increase the ram pressure P. Make adjustments. On the other hand, when the area S of the gap 5c which is sequentially calculated is in a decreasing state (the downward curve of the curve S in FIG. 4), the ram 6 is moved upward to reduce the ram pressure P.

  In this manner, control is performed such that the ram pressure P is increased as the area S of the gap 5c calculated successively increases, and the ram pressure P is reduced as the area S of the gap 5c calculated sequentially decreases. Thus, when the area S of the gap 5c calculated sequentially is the maximum area Sx, the ram pressure P is maximized, and when the area S of the gap 5c calculated sequentially is the minimum area Sn, the ram pressure P is minimized.

  According to the present invention, by sequentially calculating the area S of the gap 5c between the pair of rotors 3 in top view between the pair of rotors 3 based on the phase data, the size of the area S of the gap 5c sequentially calculated The ram pressure P can be properly adjusted based on the Thus, when the area S of the gap 5c is small, the ram pressure P applied to the kneaded material R can be reduced, and the kneaded material R can be passed between the rotors 3.

  Therefore, excessive compression of the powdery compounding agent N between the narrowed rotors 3 is prevented, and the powdery compounding agent N can be suppressed from being firmly solidified into a lump. Along with this, it is advantageous to disperse the powdery compounding agent N more uniformly in the raw rubber G.

  On the other hand, when the area S of the gap 5c is large, the ram pressure P applied to the kneaded material R can be further increased to allow the kneaded material R to pass between the rotors 3. Therefore, it is advantageous to perform kneading for dispersing the powdery compounding agent N more uniformly in the raw material rubber G in a shorter time without excessively compressing the powdery compounding agent N between the rotors 3.

  There is also an advantage that the load acting on the rotationally driven rotor 3 can be reduced by reducing the ram pressure P applied to the kneaded material R to be passed between the narrowed rotors 3. Along with this, it is advantageous to reduce the amount of power required to rotationally drive the rotor 3.

  Test kneading is performed before kneading the kneaded product R in the production line, and the ram pressure P which can prevent the powdery compounding agent N passing between the rotors 3 from becoming a firmly solidified lump; It is good to grasp the correlation with the size of the area S. And when knead | mixing the kneaded material R and mass-producing an unvulcanized rubber material, it is desirable to adjust ram pressure P by the control part 12 using this grasped | ascertained correlation.

  The present invention is particularly useful when the pair of rotors 3 is of the meshing type, since the variation in the volume V of the gap 5c between the rotors 3 with each other and the receiving space 5b above between the rotors 3 is relatively large. However, even if one set of rotors is non-engaging, if the gap between the rotors and the variation of the volume of the receiving space above each other are relatively large due to the phase due to the rotation of the pair of rotors, The present invention can be applied.

  Powdered silica has a low bulk density, so it is likely to be over-compressed in the closed type kneader 2, and if over-compacted, it tends to solidify strongly and to become a hard crush. Therefore, when the kneaded material R contains silica as the powdery compounding agent N, the present invention is particularly advantageous.

  The present invention is also applicable to the case where the raw material rubber G and the compounding agent N, which have been previously kneaded, are added together and kneaded. The present invention can also be applied to the case where the vulcanized compounding agent N is kneaded with the kneaded product R in which the non-vulcanized compounding agent N is kneaded with the raw rubber G.

  The raw material rubber and a predetermined amount of powdery silica were put together into a kneading chamber and kneaded using a device similar to the closed type kneader illustrated in FIGS. 1 to 5. As shown in Table 1, only the presence or absence of adjustment of the ram pressure applied to the raw material rubber and the kneaded material of silica is different in two ways (cases 1 and 2), the dispersibility of silica, the load acting on the rotating rotor I confirmed the size. In case 1 as illustrated in FIG. 4, adjustment is made to increase the ram pressure when the area of the gap in a top view between the rotors is in an increasing state and to reduce the ram pressure when the area is in a decreasing state. went. The ram pressure was brought to a predetermined maximum when this area was at a maximum. Case 2 always kept at the predetermined maximum value without adjusting the ram pressure.

  The dispersibility of the silica confirmed the number of the strongly solidified and lumped silica in the raw material rubber after kneading, and in Table 1, the index was evaluated with the case 1 as the index 100 as a standard. The smaller the index value is, the smaller the number of silica lumps, and the better the dispersibility, as the silica is uniformly dispersed.

  The magnitude of the load acting on the rotor was index-evaluated in Table 1 with Case 1 as the reference index 100. The smaller the index value, the smaller the load.

  From the results in Table 1, it can be seen that Case 1 is superior to Case 2 in the dispersibility of silica. Also, it can be seen that Case 1 has a smaller load acting on the rotating rotor than Case 2 and is effective for energy reduction.

Reference Signs List 1 kneader 2 closed type kneader 3 rotor 4a rotary shaft 4b stirring blade 5 kneading chamber 5a upper end opening 5b receiving space 5c gap 6 ram 6a ram chamber 7 oil feeding unit 8 feeding mechanism 9 hopper 10 combination agent loading unit 11 discharging door 12 Control part 12a Power meter 13 Temperature sensor 14 Pressure sensor G Raw rubber N Compounding agent R Kneaded

Claims (8)

It is possible to move up and down a pair of rotors disposed inside the kneading chamber and the upper side of the kneading chamber by closing the upper end opening of the kneading chamber containing a raw material rubber and a powdery compounding agent. Method of mixing rubber materials using a closed type kneader equipped with
The phase data by rotation of the set of rotors is input to the control unit, and the area of the gap in top view between the set of rotors is sequentially calculated by the control unit based on the phase data, and the calculation is sequentially performed It is characterized by knead | mixing by the said set of rotors which rotate the said kneaded material thrown into the said kneading chamber, adjusting the ram pressure which acts on the said ram by the said control part based on the magnitude | size of the area of a clearance gap. Method of kneading rubber materials to be used.   The method for kneading a rubber material according to claim 1, wherein the one set of rotors is a meshing type rotor arranged so that the outer peripheral surfaces thereof mesh with each other.   The ram pressure is increased when the area of the sequentially calculated gap is in an increasing state, and the ram pressure is decreased when the area of the sequentially calculated gap is in a decreasing state. A method of kneading a rubber material as described above.   The method for kneading a rubber material according to any one of claims 1 to 3, wherein the compounding agent contains at least silica. A kneading chamber into which a kneaded material containing raw material rubber and powdery compounding agents is charged, a pair of rotors disposed inside the kneading chamber, and moving up and down above the kneading chamber, the kneading chamber In a rubber material kneading apparatus having a closed type kneader provided with a ram capable of closing an upper end opening,
The control unit to which phase data due to the rotation of the one set of rotors is input, and a pressure sensor for detecting a ram pressure acting on the ram, the one set of rotors by the control unit based on the phase data The area of the gap in top view in between is sequentially calculated, and the ram pressure detected by the pressure sensor is adjusted by the control unit based on the size of the area of the gap sequentially calculated, and the kneading is performed. A kneading apparatus for a rubber material, wherein the kneaded material introduced into a chamber is kneaded by the pair of rotating rotors.   The rubber material kneading apparatus according to claim 5, wherein the one set of rotors is a meshing type rotor arranged so that the outer peripheral surfaces thereof mesh with each other.   The ram pressure is increased when the sequentially calculated area of the gap is in an increasing state, and the ram pressure is decreased when the sequentially calculated area of the gap is in a decreasing state. Or the kneading | mixing apparatus of the rubber material as described in 6.   The rubber material kneading apparatus according to any one of claims 5 to 7, wherein at least silica is contained as the compounding agent.

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