JP2008023843A - Method and device for kneading rubber material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for kneading rubber material superior in productivity, which enables a stable kneading operation for a long time while reducing the load on a scraper for peeling a rubber material winding around a kneading roll. <P>SOLUTION: After the rubber material R winding around a high speed side kneading roll 2a is peeled by a scraper 10 and dropped, when a press roll 11 presses the rubber material R to the transporting surface of a delivery conveyer 6 where the rubber material has been dropped, the peeled rubber material R tends to shrink from the state nipped and pressed with the kneading rolls 2a and 2b, and a tension T is generated in the rubber material R between the scraper 10 and the roll 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a rubber material kneading method and a kneading apparatus, and more specifically, a material kneading method and kneading apparatus that smoothly separates while reducing the load on a scraper that peels off a rubber material wound around a kneading roll. It is about.

  Conventionally, rubber materials before vulcanization used in the manufacture of rubber products such as tires are made by charging a predetermined amount of raw rubber such as natural rubber and a compounding agent such as carbon black into a closed kneader called a Banbury mixer. A method of kneading to a target viscosity with a roll kneader after pre-kneading is common.

  The roll kneader is composed of a pair of kneading rolls that sandwich the rubber material, and a conveyor that forms a circulation path for conveying the rubber material again upward from below the pair of kneading rolls. It is designed to knead.

  When the rubber material has high adhesiveness, there has been a problem that the rubber material that has passed between the kneading rolls does not fall on the lower conveyor but is wound around the kneading rolls. In order to give a high shearing force to the rubber material, when the surface speeds of the pair of kneading rolls are set to be different, the high speed side kneading roll is wound due to the characteristics of the rubber material. In such a case, it is necessary to interrupt the kneading operation and peel off the wound rubber material, which causes a decrease in the productivity of the kneaded rubber.

  In order to solve this problem, a kneading apparatus has been proposed in which a scraper is disposed on the surface of the kneading roll, the rubber material wound around the kneading roll is peeled off, and dropped onto a conveyor disposed below (for example, Patent Document 1).

  However, since an excessive load is applied to the scraper when the rubber material is peeled off, the scraper is likely to be damaged, worn, stopped due to overcurrent, or thermal trip (stopped due to heat generation). It was difficult to perform the kneading operation while peeling the material.

In order to solve this problem, scrapers having various rotating structures (for example, see Patent Documents 2 and 3) have been proposed, but it cannot be said that kneading can be performed while being sufficiently stable and separated.
JP 59-201837 A JP 7-214546 A JP 2005-125498 A

  An object of the present invention is to provide a rubber material kneading method and a kneading apparatus excellent in productivity that enable a stable kneading operation for a long time while reducing a load of a scraper for peeling off a rubber material wound around a kneading roll. There is.

  In order to achieve the above object, the rubber material kneading method according to the present invention conveys the rubber material while being sandwiched between a pair of kneading rolls, and drops the rubber material wound around the kneading roll onto a lower conveyor while separating with a scraper. After that, when the material is again conveyed above the pair of kneading rolls and repeatedly kneaded, the rubber material is conveyed while being pressed by a pressing roller at a dropping position on the conveyor.

  The rubber material kneading apparatus of the present invention is provided with a pair of kneading rolls and a conveyor that forms a circulation path from the lower position of the pair of kneading rolls to the upper position again, and the high speed side of the pair of kneading rolls A scraper is arranged on the kneading roll, and a pressing roller for pressing the rubber material on the conveyor is arranged below the high-speed side kneading roll.

  According to the rubber material kneading method and the kneading apparatus of the present invention, the rubber material which has been peeled off by the scraper and dropped onto the conveyor is pressed by the presser roll at the dropping position. Some rubber material tends to shrink after being peeled from the kneading roll. This shrinking force can generate a tension in the rubber material between the scraper and the presser roll, and this tension acts to peel off the rubber material wound around the kneading roll, which places an excessive load on the scraper. And can be released smoothly over a long period of time.

  In addition, since the tension due to the contraction force of the rubber material is used as described above, the load on the scraper can be reduced, and a stable kneading operation for a long time can be performed while preventing the scraper from being damaged or worn. Thus, the kneading operation can be performed continuously without interruption, and kneading with high productivity can be performed.

  Hereinafter, a rubber material kneading apparatus and a kneading method of the present invention will be described based on the embodiments shown in the drawings. As illustrated in FIG. 1, the kneading apparatus 1 of the present invention includes a pair of opposing kneading rolls 2 a and 2 b, a conveying surface extending in the horizontal direction from below the kneading rolls 2 a and 2 b, and from the middle to the vertical direction A delivery conveyor 6 having a rotatable transport surface is arranged. Above the delivery conveyor 6, a presser roll 11 that presses the rubber material R against the conveying surface, a temperature sensor 7 that detects the rubber temperature, and a cooling fan 8 that cools the rubber material R are disposed.

  A kneading conveyor 5 is arranged from above the rotating portion of the delivery conveyor 6 so as to extend above the kneading rolls 2a and 2b. A circulation path for repeatedly supplying the rubber material R between the kneading rolls 2 is formed by the kneading conveyor 5 and the delivery conveyor 6.

  The pair of kneading rolls 2a and 2b have the same outer diameter and are rotationally driven in opposite directions by electric motors 4 provided separately, and the rotational speeds can be independently adjusted. The surface speed of the kneading roll 2a on the side where the delivery conveyor 6 is arranged is set to be higher than that of the other kneading roll 2b.

  A scraper 10 is disposed in the vicinity of the surface of the high speed side kneading roll 2a. The scraper 10 is arranged in parallel with substantially the same width as the high-speed kneading roll 2a, and has peeling blades that project radially from the rotation axis. The peeling blade is configured to rotate in the same direction as the rotation direction of the high-speed kneading roll 2a by an electric motor (not shown).

  The scraper 10 is not limited to the structure exemplified above as long as the rubber material R can be peeled off. By making the scraper 10 a simple wedge-shaped iron plate or the like, the structure can be simplified, and as exemplified above, the structure can be reduced by rotating the blade-like body. it can.

  In addition, a gap sensor for detecting the roll gap of the kneading rolls 2a and 2b is provided, and the low speed side kneading roll 2b is provided with an actuator 3 so that the roll gap can be changed by moving the low speed side kneading roll 2b.

  The electric power level (drive torque), roll surface speed, roll gap, and rubber temperature data of the electric motor 4 are transmitted to the control device 9. Based on these data, the control device 9 can control the surface speed of the kneading rolls 2a and 2b, the roll gap, the conveying speed of the transfer conveyor 5 and the rewinding conveyor 6, and can control the rubber temperature in the circulation path. ing. In this way, the rubber material R is kneaded so that an appropriate shearing force is imparted to the rubber material R by the kneading rolls 2a and 2b so as to reach the target viscosity within a predetermined kneading time.

  The kneading apparatus 1 is charged with a rubber material R in which a raw rubber and a non-vulcanizing compound such as carbon black are preliminarily kneaded by a Banbury mixer. In the case of the rubber material R having low adhesiveness, the rubber material R does not wind around the kneading rolls 2a and 2b. Therefore, the rubber material R is sandwiched between the kneading rolls 2a and 2b as shown in FIG. It falls onto the conveying surface of the delivery conveyor 6 that has been provided, and is continuously conveyed as it is above the kneading rolls 2a and 2b and supplied between the kneading rolls 2a and 2b.

  However, when the rubber material R to be kneaded contains silica blended rubber containing silica and a silane coupling agent or silica blended rubber in part, since the adhesiveness is high, the speed is high as shown in FIG. It may stick to the surface of the side kneading roll 2a and wind up. When wound in this way, the rubber material R that has passed between the kneading rolls 2a and 2b does not fall on the delivery conveyor 6, but the rubber material R is circulated and cannot be kneaded. In FIG. 2, some of the components are omitted.

  In the case of kneading such a rubber material R having high adhesiveness, in the present invention, the peeling blade of the scraper 10 disposed in the vicinity of the surface of the high speed side kneading roll 2a around which the rubber material R is wound is used for this kneading. The rolled rubber material R is peeled off by rotating in the same direction as the rotation direction of the roll 2a.

  Since the rubber material R is wound around the kneading roll 2a having a relatively high surface speed, in this kneading apparatus 1, the side on which the delivery conveyor 6 and the kneading conveyor 5 are arranged (the right side in FIG. 2) is the high speed side kneading roll. 2a, the surface speed V1 is set higher than the surface speed V2 of the other kneading roll 2b.

  Accordingly, the scraper 10 need only be provided for the high-speed kneading roll 2a, and the rubber material R that has passed through the kneading rolls 2a and 2b is dropped in the direction of conveyance of the delivery conveyor 6 and smoothly circulated. I try to let them.

  The present invention can also be applied to the case where the surface speeds V1 and V2 of both the kneading rolls 2a and 2b are the same. In this case, the scraper 10 is provided for both the kneading rolls 2a and 2b.

  The rubber material R peeled off from the surface of the high-speed side kneading roll 2a is pressed by the holding roll 5 on the conveying surface of the delivery conveyor 6 disposed below. Here, the rubber material R that has been sandwiched between both the kneading rolls 2a and 2b will shrink from the rolled state when it is separated from the kneading roll 2a by the scraper 10 after passing through the kneading rolls 2a and 2b. And Due to the contraction force of the rubber material R, a tension T is generated in the continuous rubber material R between the scraper 10 and the presser roll 11.

  The tension T acts to peel off the rubber material R wound around the high-speed kneading roll 2 a, and the rubber material R is smoothly separated by the cooperation of the scraper 10 and the presser roll 11. Further, since the wound rubber material R is easily peeled off by the tension T, the load on the scraper 10 is reduced, and the rubber material R can be peeled off stably for a long period of time by preventing the scraper 10 from being damaged or worn. it can.

  Thereby, the kneading operation can be reduced without interrupting the rubber material R wound around the high speed side kneading roll 2a or the number of interruptions can be reduced, and the kneaded rubber can be obtained with high productivity.

  Further, the relative speed between the transfer speed V3 of the transfer conveyor 6 and the surface speed V1 of the high-speed kneading roll 2a is controlled, and the transfer conveyor 6 transfers the continuous rubber material R between the scraper 10 and the presser roll 11 to the transfer material. A tension T can be generated by generating a speed difference between the front end and the rear end in the direction. With this tension T, the rubber material R wound around the high-speed kneading roll 2a can be more easily peeled off.

  Although it depends on the characteristics of the rubber material R, since it is an unvulcanized rubber material R, if the distance between the scraper 10 and the pressing roller 11 exceeds 1 m, the generated tension T causes the rubber material R to extend and plastically deform. And is not easily transmitted to the rubber material R wound around the high-speed kneading roll 2a. Therefore, this interval is preferably about 1 m or less, and the lower limit is defined by the necessary clearance between the high-speed kneading roll 2a and the delivery conveyor 6.

  Further, the transfer speed V3 of the delivery conveyor 6 also varies depending on the characteristics of the rubber material R, but is preferably about 90% to 120% of the surface speed V1 of the high speed side kneading roll 2a. When the conveyance speed V3 is less than 90% of the surface speed V1, particularly in the case of the rubber material R having a small shrinkage rate, the generated tension T is small, so the effect of assisting the peeling of the rubber material R is small. In the case of the rubber material R having a large shrinkage rate, an excessive tension T is generated, and there is a high possibility that the rubber material R is broken between the scraper 10 and the presser roll 11. In addition, in order to smoothly deliver the rubber material R from the delivery conveyor 6 to the kneading conveyor 5, the same conveying speed V3 is set.

  The scraper 10 is preferably arranged so that the point P closest to the high speed side kneading roll 2a (hereinafter referred to as the proximity point P) is located below the rotation center of the high speed side kneading roll 2a. It is particularly preferable to arrange the transfer conveyor 6 on the transport direction side (right side in FIG. 2) from the rotation center of the high-speed kneading roll 2a. By arranging in this way, it becomes easy to drop the rubber material R which has been peeled off onto the transfer surface of the delivery conveyor 6.

  The presser roll 11 has a perpendicular center VL drawn downward from the proximity point P of the scraper 10 and an angle A of 45 ° with respect to the perpendicular direction VL from the proximity point P to the conveying direction side of the delivery conveyor 6. It is preferable to arrange so as to be positioned between the drawn oblique line SL. By arranging in this way, the rubber material R wound from the high-speed kneading roll 2a can be easily peeled off, and the flow of the rubber material R from the peeling to the pressing on the transfer surface of the delivery conveyor 6 can be made smooth. .

  FIG. 3 shows an enlarged part of another embodiment and omits some of the components. The scraper 10 of the kneading apparatus 1 is provided with a sensor 12 that detects a load (for example, a rotational load) generated when the rubber material is peeled off. The detection signal of the sensor 12 is transmitted to the control device 9.

  Based on the detection signal of the sensor 12, the control device 9 calculates the presence and amount of the rubber material R wound around the high-speed kneading roll 2a. Based on the calculation result, the control device 9 controls the transport speed V3 of the transfer conveyor 6 and the kneading conveyor 5 and the surface speed V1 of the high-speed kneading roll 2a, and determines the speed difference between the transport speed V3 and the surface speed V1. Control.

  For example, when the amount of the rubber material R wound around the high-speed kneading roll 2a is large and the load of the scraper 10 is large, the speed increase rate of the conveying speed V3 is increased to increase the speed difference from the surface speed V1. Increase the tension T. When the rubber material R wound around is small and the load on the scraper 10 is small, the speed increase rate of the transport speed V3 is lowered to reduce the speed difference from the surface speed V1.

  The amount of the rubber material R wound around the high speed side kneading roll 2a can also be grasped by the load of the presser roll 11 after peeling. Therefore, the sensor 12 may be attached to the presser roll 11.

  Based on the detection signal of the sensor 12 that detects the load of the presser roll 11 generated by the rubber material R immediately after peeling, the transfer conveyor 6 and the reversing conveyor 5 are configured by the control device 9 in the same manner as described above. The speed difference between the transport speed V3 and the surface speed V1 of the high-speed kneading roll 2a is controlled.

It is a schematic side view which illustrates embodiment of the kneading apparatus of this invention. It is a schematic side view which expands and shows a part of FIG. It is a schematic side view which expands and partially shows other embodiment of a kneading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Kneading apparatus 2a High speed side kneading roll 2b Low speed side kneading roll 3 Actuator 4 Electric motor 5 Mixing conveyor 6 Delivery conveyor 7 Temperature sensor 8 Cooling fan 9 Control apparatus 10 Scraper 11 Pressing roll 12 Stress sensor

Claims (9)

  The rubber material is conveyed while being sandwiched between a pair of kneading rolls, and the rubber material wound around the kneading roll is dropped on a lower conveyor while being separated by a scraper, and then again conveyed above the pair of kneading rolls and repeatedly. A method for kneading a rubber material in which the rubber material is conveyed while being pressed by a pressing roller at a dropping position on the conveyor when kneading.   The method for kneading a rubber material according to claim 1, wherein a conveying speed of the conveyor is 90% to 120% of a surface speed of a kneading roll around which the rubber material is wound.   A sensor for detecting a load is provided on at least one of the scraper or the presser roll, and based on a detection signal of the sensor, a speed difference between the conveying speed of the conveyor and the surface speed of the kneading roll around which the rubber material is wound is controlled. The rubber material kneading method according to claim 1 or 2.   The method for kneading a rubber material according to any one of claims 1 to 3, wherein the rubber material is a silica-containing rubber containing silica and a silane coupling agent.   A pair of kneading rolls and a conveyor that forms a circulation path from a lower position of the pair of kneading rolls to an upper position again, a scraper is disposed on the high-speed kneading roll of the pair of kneading rolls, and the high-speed side A rubber material kneading apparatus in which a presser roller for pressing the rubber material on the conveyor is disposed below the kneading roll.   The rubber material kneading apparatus according to claim 5, wherein a conveying speed of the conveyor is set to 90% to 120% of a surface speed of the high speed side kneading roll.   The rubber material kneading apparatus according to claim 5 or 6, wherein the scraper has a configuration in which blades project radially from a rotation shaft and rotates in the same direction as the rotation direction of the high-speed kneading roll.   The scraper and the presser roll are arranged so that the distance between them is 1 m or less, and the scraper is located closest to the high-speed side kneading roll at a lower point than the rotation center of the high-speed side kneading roll, And while arrange | positioning so that it may be located in the conveyance direction side of the conveyor arrange | positioned under the said pair of kneading rolls rather than this rotation center, the perpendicular | vertical line which the center pulled down from the said proximity | contact point And it arrange | positions so that it may be located between the oblique line drawn so that the 45 degree angle might be made to the conveyance direction side of the said conveyor arrange | positioned under the said pair of kneading rolls from the said proximity point with respect to this perpendicular line. A rubber material kneading apparatus according to 5-7.   A sensor for detecting a load is provided in at least one of the scraper or the presser roll, and a speed difference between the conveying speed of the conveyor and the surface speed of the high-speed kneading roll is controlled based on a detection signal transmitted from the sensor. The rubber material kneading apparatus according to any one of claims 5 to 8, wherein a controller is provided.

Images