JP4639981B2 - Kneading control method of silica compound rubber - Google Patents

Description

  The present invention relates to a method for controlling the kneading of a silica-blended rubber. More specifically, the present invention relates to a silica-blended rubber excellent in productivity capable of improving the dispersibility of silica to stabilize the quality and obtaining a rubber having a target viscosity. This relates to a kneading control method.

  For tire tread rubber and the like, it is known to improve the fuel efficiency and wet grip performance of a tire by using a silica-containing rubber containing silica. However, since silica easily aggregates between particles, the dispersibility to rubber is poor, and the dispersibility is improved by adding a silane coupling agent and causing a coupling reaction with silica. For such kneading of the silica-containing rubber, various optimum kneading temperatures have been proposed (see, for example, Patent Document 1).

  Conventionally, this silica compound rubber has been kneaded by using a closed mixer 1 called a Banbury mixer as shown in FIG. The kneading method involves kneading for a predetermined time so that the rubber temperature of the silica-blended rubber R1 does not rise excessively, then releasing and cooling, and kneading again with a closed mixer to promote the coupling reaction to promote silica. Kneading until the target viscosity is reached.

However, when the closed mixer 1 is repeatedly kneaded repeatedly, the kneading time becomes long. As a result, the rubber amount of the silica-blended rubber R1 that can be obtained by kneading with the closed mixer 1 for a predetermined time. There is a problem that productivity cannot be increased.
JP 2000-119400 A

  An object of the present invention is to provide a kneading control method of a silica-containing rubber excellent in productivity and capable of obtaining a rubber having a target viscosity while improving the dispersibility of silica to stabilize the quality.

In order to achieve the above object, the kneading control method for silica compounded rubber of the present invention is a kneading control method for silica compounded rubber in which a silica compounded rubber compounded with silica and a silane coupling agent is kneaded to the target viscosity, In addition, a preliminarily set amount of heat history necessary for completion of the reaction of silica and silane coupling agent is given by kneading with a closed mixer, and then placed in series in the closed mixer Using the at least two roll kneaders , the silica compounded rubber released from the hermetic mixer was mixed with the first roll kneader so that the roll gap was 3 mm to 15 mm and the rubber temperature was 90 ° C. to 160 ° C. Control and kneading, and then kneading with a second roll kneader while controlling the roll gap to 1 mm to 10 mm and the rubber temperature to 40 ° C. to 100 ° C. Ri, is characterized in applying the rest of the thermal history of the thermal history amount necessary to the completion of the reaction.
Further, another silica compounded rubber kneading control method of the present invention is a silica compounded rubber kneading control method for kneading silica compounded rubber compounded with silica and a silane coupling agent to a target viscosity. A heat history amount in the middle of the heat history amount required for the completion of the reaction between the silica and the silane coupling agent set in advance was applied by kneading with a closed mixer, and then placed in series with the closed mixer. Using at least two roll kneaders, the silica compound rubber released from the hermetic mixer is kneaded with the first roll kneader at a temperature of 90 ° C. or higher. The rubber temperature to be discharged is controlled to 120 ° C. to 160 ° C., and the rubber temperature charged into the second roll kneader for kneading the discharged kneaded rubber is subsequently set to 100 ° C. to 160 ° C. By controlling the rubber temperature to discharge by kneading in machine in 40 ° C. to 100 ° C., and is characterized in applying the rest of the thermal history of the thermal history amount necessary to the completion of the reaction.

  According to the kneading control method for kneading the silica-blended rubber of the present invention to the target viscosity, the heat history amount in the middle of the heat history amount required for the completion of the reaction between the silica and the silane coupling agent is set in the silica-blended rubber. Since it is applied by kneading with a closed mixer, the kneading time in the closed mixer can be shortened and the occupation time of the closed mixer can be shortened. Thereby, the rubber amount of the silica-containing rubber released from the closed mixer at a predetermined time can be increased, and the productivity of the closed mixer can be improved.

  Following this, the silica compounded rubber discharged from the closed mixer is kneaded with a roll kneader to give the remaining amount of heat history necessary for the completion of the reaction. As a result, the quality can be stabilized, and the viscosity can be lowered by applying a shearing force to obtain a silica-containing rubber having a target viscosity.

  In this way, by mixing and kneading a closed mixer and a roll kneader, it is possible to obtain a silica-containing rubber having a stable target viscosity with a stable quality at shorter intervals, and having excellent productivity. Become.

  Hereinafter, the kneading | mixing control method of the silica compounding rubber | gum of this invention is demonstrated based on embodiment shown in the figure. FIG. 1 illustrates an overall outline of a kneading system that performs kneading.

  If the silica compounded rubber R1 does not accelerate and complete the coupling reaction with silica and a silane coupling agent, the dispersibility to rubber cannot be improved and stable quality cannot be obtained. Therefore, first, raw material rubber, non-vulcanized compounding agent, silica and coupling agent are kneaded for a predetermined time by a Banbury mixer (closed mixer) 1. By this kneading, an intermediate heat history amount necessary for the completion of the coupling reaction is imparted. The amount of heat history is obtained by multiplying the amount of heat applied and the application time, and details will be described later.

  Thereafter, the released silica compounded rubber R1 passes through a biaxial roll called a dump roll 2 disposed adjacent to the Banbury mixer 1, and is conveyed to the roll kneader 4 by the conveyor belt 3.

  In this kneading system, two roll kneaders 4 and 4 are arranged in series, and the silica compounded rubber R1 is kneaded by the second roll kneader 4 following the first roll kneader 4 to be the target. It becomes a silica-containing rubber R1 having a viscosity. Further, the kneading by the roll kneader 4 gives the remaining heat history amount necessary for the completion of the coupling reaction.

  On the roll 5 of the roll kneader 4, a pair of roll guides 5a and 5a for guiding the silica-containing rubber R1 are provided with a variable guide width W. In addition, the number of the roll kneaders 4 arranged in series with the Banbury mixer 1 is not limited to two, and is appropriately determined.

  The silica-containing rubber R1 that has completed the coupling reaction and has reached the target viscosity is conveyed to the final kneader 14 by the conveyor belt conveyor 3 arranged at the end of the second roll kneader 4, where it is vulcanized. It is kneaded with a vulcanizing compound compounding agent Q such as sulfur or a vulcanization accelerator introduced by the system compounding agent charging device 15, and becomes a final kneaded rubber R2 in which all the compounding agents are compounded.

  The final kneaded rubber R2 is further transported to the sheeting device 16 by the transport conveyor belt 3, where it becomes sheet rubber, transported to the cooling device 18 by the transport belt conveyor 3 in which the sampling device 17 is installed, and used in the next process. Stored in place until done. The final kneaded rubber R2 is used as a molded member in the next step, for example.

  Thus, in the kneading by this kneading system, the amount of heat history necessary for the completion of the coupling reaction is distributed and applied to the silica compounded rubber R1 in the kneading by the Banbury mixer 1 and the kneading by the roll kneader 4; The final kneading rubber R2 is obtained by kneading until the target viscosity is reached by the roll kneader 4. As a result, compared with the conventional kneading by the Banbury mixer 1, it is possible to continuously obtain the silica compounded rubber R1 having a target viscosity with improved quality by improving the dispersibility of the silica at a short predetermined interval. That is, the productivity is excellent, and as a result, the required amount of the final kneaded rubber R2 can be obtained with a reduced lead time.

  The amount of heat history necessary for completing the coupling reaction will be described below. FIG. 3 illustrates the relationship between the heat history amount imparted to the silica compounded rubber R1 by kneading and the viscosity. As shown in FIG. 3, the viscosity of the silica-containing rubber R1 changes depending on the amount of heat history. Each composition has a unique heat history amount that minimizes the viscosity. The point at which this viscosity is minimized is defined as the completion of the coupling reaction, for example. This reveals the amount of heat history necessary to complete the coupling reaction. For example, as shown in FIG. 3, the heat history amounts necessary for completing the coupling reaction in the rubbers of the blends C1 and C2 are Q1 and Q2, respectively.

  As described above, the amount of heat history necessary for completing the coupling reaction for each blending is grasped and set in advance and used in the kneading control method of the present invention.

  This preset amount of heat history is distributed to kneading by the Banbury mixer 1 and the roll kneader 4 and applied to the silica compounded rubber R1. FIG. 4 illustrates the relationship between the amount of heat history applied by kneading and time. For example, in FIG. 4, the heat history amount q1 in the middle of the heat history amount Q1 necessary for completing the coupling reaction is given by the kneading of the Banbury mixer 1 during the first kneading time (0 to t1). To be controlled. The remaining amount of heat history (Q1-q1) is controlled so as to be applied by the kneading of the roll kneader 4 during the subsequent kneading time (t1-t2).

  The distribution ratio of the heat history amount Q1 necessary for completing the coupling reaction to the Banbury mixer 1 and the roll kneader 4 is appropriately determined.

  When two or more roll kneaders 4 are arranged in series and continuously kneaded, the first roll kneader 4 kneads at a relatively high temperature, and the heat history remaining after kneading in the Banbury mixer 1 It is preferable to stabilize the quality by imparting an amount and promoting and completing the coupling reaction to improve the dispersibility of silica in rubber.

  In the subsequent kneading of the second roll kneader 4, kneading at a lower temperature than the first roll kneader 4, giving a large shearing force to the silica-blended rubber R 1, and promoting a decrease in viscosity, Knead until the target viscosity is reached.

For example, the silica compounded rubber R1 discharged from the Banbury mixer 1 is compared with the first roll kneader 4 with a roll gap h of 3 mm to 15 mm to suppress heat radiation and the rubber temperature T is controlled to 90 ° C. to 160 ° C. By kneading in a moderately high temperature state, the coupling reaction can be promoted and completed, the dispersibility of silica in rubber can be improved, and the quality can be stabilized.
Following this, the second roll kneader 4 sets the roll gap h to 1 mm to 10 mm to facilitate heat dissipation, giving effective shearing force for reducing the viscosity of the silica compounded rubber R1, and adjusting the rubber temperature T to the viscosity. By controlling and kneading at 40 ° C. to 100 ° C. which is effective for reduction, viscosity reduction can be promoted and the target viscosity can be achieved.

  As another kneading control method, the temperature T of the rubber added to the first roll kneader 4 of the silica compounded rubber R1 discharged from the Banbury mixer 1 in a range of approximately 90 ° C. or higher and 170 ° C. or lower is set to 90 ° C. or higher. This eliminates the need for special cooling of the silica-blended rubber R1 before it is put into the roll kneader 4, thereby minimizing time and energy loss. And by controlling the rubber temperature T which is kneaded and discharged by the first roll kneader 4 to 120 ° C. to 160 ° C., the coupling reaction is promoted and completed, and the dispersibility of silica with respect to the rubber is improved. The quality can be stabilized.

  Subsequently, the rubber temperature T supplied to the second roll kneader 4 for kneading the discharged silica compounded rubber R1 is set to 100 ° C. to 160 ° C., and the rubber temperature T from the first roll kneader 4 is substantially the same. The rubber temperature T that is kneaded and discharged by the second roll kneader 4 is controlled to 40 ° C. to 100 ° C., which is effective for reducing the viscosity, and the viscosity reduction is efficiently promoted. can do.

  As illustrated in FIG. 2, the two roll kneaders 4 and 4 are composed of a pair of opposed rolls 5 and 5, a reverse conveyor belt 7, a transfer conveyor belt 13, and the like. The circulation path of the silica compounded rubber R1 is formed by the conveyor belt 13, and the silica compounded rubber R1 repeatedly roll passes between both the rolls 5 and 5, whereby the silica compounded rubber R1 is sheared and kneaded to reduce the viscosity.

  The pair of rolls 5 and 5 of the roll kneader 4 are rotationally driven by electric motors 8 in opposite directions, and one roll 5 is provided with an actuator 9 so that the roll 5 can be moved to change the roll gap h. . A roll gap sensor 11 is disposed between the rolls 5 and 5, and a temperature sensor 10 for detecting the rubber temperature T of the silica-blended rubber R 1 and a cooling fan for cooling the silica-blended rubber R 1 are disposed above the delivery conveyor belt 13. 6 is arranged. Each data of the electric power level P (drive torque), roll surface speed V, roll gap h, and rubber temperature T of the electric motor 8 is transmitted to the arithmetic unit 12 and can be controlled.

  The amount of heat history applied by the roll kneader 4 is calculated by the calculation device 12 based on the measurement data from the temperature sensor 10 and the kneading time. Here, the amount of heat history in the roll kneader 4 varies depending on the external environment, heat generation of the silica-blended rubber R1 during kneading, and the like, so the heat history applied during kneading by the first roll kneader 4 The amount is sequentially calculated by the calculation device 12.

  A target heat history amount given by the first roll kneader 4 determined on the basis of the heat history amount necessary for the completion of the coupling reaction is set in the arithmetic device 12 in advance. The kneading conditions in the first roll kneader 4 are controlled so that the amount and the calculated heat history amount coincide with each other. This kneading completes the coupling reaction.

  For example, in order to give the target heat history amount for a predetermined time, at least one of the roll surface speed V, the roll surface speed ratio, the roll gap h, and the roll guide width W of the first roll kneader 4 is controlled. The arithmetic unit 12 controls the degree of increase / decrease in the roll surface speed V and the roll surface speed ratio, and the degree of expansion / contraction of the roll gap h and the roll guide width W, thereby adjusting the amount of heat given to the silica compounded rubber R1 being kneaded over time. To do. The roll surface speed ratio is the ratio of the surface speed of the other roll 5 to the one roll 5 serving as a reference in the pair of rolls 5 and 5. The amount of heat increases as the roll surface speed ratio increases from 1.

  As described above, by controlling the kneading conditions in the first roll kneader 4, the coupling reaction can be promoted and completed more accurately. As a result, it is possible to obtain a silica-blended rubber R1 having a target viscosity with further stable quality, and finally a final kneaded rubber R2.

  In this embodiment, the kneading conditions are controlled so that the target heat history amount is given to the silica-blended rubber R1 with respect to the first roll kneader 4, but the second roll kneader 4 A part of the heat history amount necessary for the coupling reaction can also be imparted by kneading in. In this case, the kneading conditions may be similarly controlled for the second roll kneader 4.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic diagram which illustrates the whole system which implements the kneading | mixing method of this invention. It is a block diagram which illustrates the roll kneader in this invention. It is a graph which illustrates the relationship between the amount of heat history given to silica compounding rubber by kneading, and viscosity. It is a graph which illustrates the relationship between the amount of heat history given to silica compound rubber by kneading, and time. It is explanatory drawing which shows the kneading | mixing method of the conventional silica compounding rubber.

Explanation of symbols

1 Closed mixer (Banbury mixer)
2 Dump roll 3 Conveyor belt 4 Roll kneader
DESCRIPTION OF SYMBOLS 5 Roll 5a Roll guide 6 Cooling fan 7 Conveyor belt 8 Electric motor 9 Actuator 10 Temperature sensor 11 Roll gap sensor 12 Arithmetic device 13 Delivery conveyor belt 14 Final kneader 15 Vulcanization system compound injection device 16 Seating device 17 Sampling device 18 Cooling device R1 Silica compound rubber R2 Final kneaded rubber (silica compound rubber)

Claims (4)

A kneading control method of a silica compounded rubber in which a silica compounded rubber compounded with silica and a silane coupling agent is kneaded to a target viscosity, which is necessary for completion of the reaction of silica and a silane coupling agent set in advance in the silica compounded rubber. An intermediate amount of heat history is imparted by kneading with a closed mixer, and then using at least two roll kneaders arranged in series with the closed mixer , the closed mixer The silica-blended rubber released from the kneaded rubber is kneaded with a first roll kneader while controlling the roll gap at 3 mm to 15 mm and the rubber temperature at 90 ° C. to 160 ° C., and then the second roll kneader is used to knead the roll gap. by kneading by controlling the 1mm~10mm and rubber temperature 40 ° C. to 100 ° C., to impart the remaining thermal history of the thermal history the amount required in the reaction completed Kneading method of controlling mosquitoes compounded rubber. A kneading control method of a silica compounded rubber in which a silica compounded rubber compounded with silica and a silane coupling agent is kneaded to a target viscosity, which is necessary for completion of the reaction of silica and a silane coupling agent set in advance in the silica compounded rubber. An intermediate amount of heat history is imparted by kneading with a closed mixer, and then using at least two roll kneaders arranged in series with the closed mixer , the closed mixer The rubber temperature charged into the first roll kneader of the silica-blended rubber released from is controlled to 90 ° C. or higher, and the rubber temperature kneaded and discharged by the first roll kneader is controlled to 120 ° C. to 160 ° C. The rubber temperature charged into the second roll kneader for kneading the discharged kneaded rubber is 100 ° C. to 160 ° C., and the rubber temperature kneaded and discharged by the second roll kneader is 40 ° C. to 100 ° C. By Gosuru, kneading method of controlling silica compounded rubber to impart the remaining thermal history of the thermal history amount necessary to the completion of the reaction. Based on the measurement data of the rubber temperature of the silica-blended rubber kneaded by the first roll kneader, the amount of heat history applied to the silica-blended rubber by kneading by the first roll kneader is calculated, and the calculation is performed. The kneading conditions in the first roll kneader are controlled so that the heat history amount matches the target heat history amount given by the first roll kneader determined based on the heat history amount necessary for the completion of the reaction. The kneading | mixing control method of the silica compounding rubber of Claim 1 or 2 to do. The method for controlling the kneading of the silica-containing rubber according to claim 3 , wherein the object to be controlled of the kneading conditions is at least one of a roll surface speed, a roll surface speed ratio, a roll gap, and a roll guide width of the first roll kneader. .

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