JP2020059186A - Kneading method and system for rubber material - Google Patents

Abstract

To provide a kneading method and system for a rubber material capable of grasping a temperature of the rubber material being kneaded by a closed type kneading machine with higher accuracy.SOLUTION: A temperature of a rubber material R kneaded in a kneading chamber 5a is detected by a temperature sensor 14 arranged in the kneading chamber 5a, and a magnitude and frequency of occurrence of a load P acting on the temperature sensor 14 are detected by a load sensor 15. Then, temperature data Td detected by the temperature sensor 14 is corrected by a calculation unit 13 based on load data Pd detected by the load sensor 15 to estimate a true temperature Tr of the rubber material R, and the estimated temperature Tr is used to control a closed type kneading machine 1 by a control unit 12 to knead the rubber material R to produce a kneading rubber RF of desired quality.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a kneading method and system for a rubber material, and more particularly to a kneading method and system for a rubber material, which can grasp the temperature of the rubber material being kneaded by a closed kneader with higher accuracy.

  Rubber products such as tires and rubber hoses are manufactured by vulcanizing a molded body formed of unvulcanized kneaded rubber. The kneaded rubber is produced, for example, by kneading a rubber material including a raw material rubber and various compounding agents with a closed type kneader. In order to obtain a kneaded rubber of a desired quality, a closed type kneader detects the temperature of the rubber material during kneading and kneads the kneaded rubber so that the temperature falls within a predetermined temperature range (see, for example, Patent Document 1).

  Conventionally, a temperature sensor arranged in a kneading chamber (the drop door of the kneading chamber in the invention of Patent Document 1) is used to detect the temperature of the rubber material being kneaded by the closed type kneader. When the rubber material comes into contact with the temperature sensor, the temperature of the rubber material is detected. For example, a rubber material having a volume of 50 to 70% with respect to the capacity of the kneading chamber is charged and kneading is performed, so that there is a certain amount of voids in the kneading chamber. Therefore, the temperature data detected by the temperature sensor varies depending on the frequency of contact of the kneaded rubber material with the temperature sensor. Also, the friction data between the kneaded rubber material and the temperature sensor causes a difference in the detected temperature data. Therefore, there is room for improvement in more accurately grasping the true temperature of the rubber material during kneading.

JP, 2005-47094, A

  An object of the present invention is to provide a kneading method and system for a rubber material, which can grasp the temperature of the rubber material being kneaded by the closed kneader with higher accuracy.

In order to achieve the above object, the kneading method of the rubber material of the present invention is a kneading chamber of a closed type kneading machine, a rubber material comprising a raw material rubber and a compounding agent is kneaded by rotating a rotor provided in the kneading chamber. By kneading the rubber material to produce a kneaded rubber of desired quality,
The temperature of the rubber material being kneaded in the kneading chamber is detected by a temperature sensor arranged in the kneading chamber, and the magnitude and the occurrence frequency of the load acting on the temperature sensor are detected by a load sensor, The true temperature of the rubber material is estimated by correcting the temperature data detected by the temperature sensor based on the load data detected by the load sensor, and the estimated temperature is used to knead the rubber material. It is characterized by

  The rubber material kneading system of the present invention is a hermetically sealed machine having a kneading chamber into which a rubber material composed of raw rubber and a compounding agent is charged, a rotor arranged in the kneading chamber, and a drive motor for rotationally driving the rotor. In a kneading system for a rubber material including a mold kneader and a controller for controlling the movement of the closed kneader, the temperature of the rubber material disposed in the kneading chamber and kneaded in the kneading chamber is detected. Temperature sensor, a load sensor that detects the magnitude and frequency of occurrence of a load that acts on the temperature sensor, and an arithmetic unit to which the temperature data detected by the temperature sensor and the load data detected by the load sensor are input. And the true temperature of the rubber material is estimated by correcting the temperature data based on the load data by the calculation unit. The true by the control unit with temperature is the sealed kneader control is characterized in that a configuration in which kneading of the rubber material is performed.

  According to the present invention, the true temperature of the rubber material being kneaded is corrected by correcting the temperature data detected by the temperature sensor based on the magnitude and the frequency of the load acting on the temperature sensor arranged in the kneading chamber. Therefore, the true temperature of the rubber material can be grasped with higher accuracy. Along with this, variations in the quality of the rubber material during kneading are suppressed, which is advantageous for stably obtaining a kneaded rubber of desired quality.

It is explanatory drawing which illustrates the kneading system of this invention by making a closed type kneader into a longitudinal cross-sectional view. It is explanatory drawing which illustrates the bottom part of the kneading chamber of FIG. 1 by planar view. It is a perspective view which illustrates the temperature sensor and load sensor of FIG. It is an AA sectional view of FIG. It is explanatory drawing which illustrates the state which is kneading a rubber material using the kneading system of FIG. FIG. 6 is a graph showing the relationship between the temperature of the kneaded rubber material and the load acting on the temperature sensor.

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

  The embodiment of the kneading system for a rubber material of the present invention illustrated in FIGS. 1 to 4 is a closed kneading machine 1 (hereinafter referred to as kneading machine 1), a controller 12 for controlling the movement of the kneading machine 1, and a predetermined And the arithmetic unit 13 that performs arithmetic processing. The controller 12 and the calculator 13 are connected to each other by wire or wirelessly so that they can communicate with each other.

  The kneading machine 1 kneads the unvulcanized rubber material R. The rubber material R is composed of a raw material rubber G and a plurality of types of non-vulcanizing compounding agents N, and the compounding agent N is uniformly dispersed in the raw material rubber G by kneading to obtain a desired quality (for example, target viscosity). The kneaded rubber RF of is manufactured.

  As the raw material rubber G, 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 alone or in combination of two or more. As the non-vulcanizing compounding agent N, for example, a necessary one is appropriately selected from carbon black, silica, a silane coupling agent, zinc oxide, stearic acid and the like.

  The kneading machine 1 includes a kneading chamber 5a, a ram chamber 5b which is connected to an upper end opening of the kneading chamber 5a and extends upward, a pair of rotors 2 (2A, 2B) arranged in the kneading chamber 5a, and a ram chamber. It has a ram 6 arranged at 5b. The kneading chamber 5a is connected to the oil charging section 7, and the ram chamber 5b is connected to the rubber charging section 8 and the compounding agent charging section 10. A hopper 9 is connected to the upper end of the compounding agent charging section 10. A discharge door 11 that opens and closes is provided on the bottom surface of the kneading chamber 5a.

  Each of the rotors 2A and 2B has a rotor shaft 2c and a stirring blade 2d protruding from the rotor shaft 2c. The rotors 2A and 2B (rotor shafts 2c) are arranged to face each other, and the rotor shafts 2c are connected to the drive motors 3 (3A and 3B) via the transmission 4. Each rotor shaft 2c is rotationally driven by drive motors 3A and 3B. The rotor shafts 2c may be rotationally driven by the same single drive motor 3. The drive and stop of the rotors 2A and 2B (rotor shaft 2c), rotation speed, etc. are controlled by the control unit 12.

  The control unit 12 is provided with a power meter 12a and a tachometer 12b. The electric power meter 12a sequentially detects the amount of instantaneous electric power required to drive the rotor 2 to rotate. The instantaneous power amount data P1 detected by the power meter 12a is input to the control unit 12. The control unit 12 calculates the integrated electric energy by accumulating the instantaneous electric energy, and can grasp the integrated electric energy data P2 required for rotationally driving the rotor 2 in an arbitrary kneading period. The rotation speed of the rotor 2 is sequentially detected by the tachometer 12b and input to the control unit 12.

  A temperature sensor 14 is arranged in the kneading chamber 5a. In this embodiment, the temperature sensor 14 is arranged in a groove formed on the upper surface of the discharge door 11. The temperature sensor 14 and the calculation unit 13 are connected by wire or wirelessly so that they can communicate with each other. The temperature sensor 14 sequentially detects the temperature of the rubber material R kneaded in the kneading chamber 5a, and the detected temperature data Td is sequentially input to the calculation unit 13.

  The temperature sensor 14 can use various types that come into contact with the rubber material R. As illustrated in FIG. 3, the temperature sensor 14 of this embodiment has a thermocouple 14a and a metal casing 14b that houses the thermocouple 14a. The cylindrical casing 14b projects into the kneading chamber 5a in the recess or groove formed on the upper surface of the discharge door 11, and the upper surface of the casing 14b and the upper surface of the discharge door 11 are at the same level.

  A load sensor 15 is installed on the temperature sensor 14. In this embodiment, the load sensor 15 is installed on the inner surface of the casing 14b. The load sensor 15 and the calculation unit 13 are connected by wire or wirelessly so that they can communicate with each other. The load sensor 15 sequentially detects the magnitude of the load P acting on the temperature sensor 14 and the frequency of occurrence of the load P, and the detected load data Pd is sequentially input to the calculation unit 13. By housing the load sensor 15 in the casing 14b, it is possible to avoid the kneaded rubber material R from directly colliding with the load sensor 15.

  Although various types of load sensors 15 can be used, a strain gauge is used as the load sensor 15 in this embodiment. Based on the deformation of the casing 14b, the load sensor 15 detects the magnitude of the load P acting on the casing 14b and the frequency of occurrence of the load P. When a strain gauge is used as the load sensor 15, it is easy to handle, and it is easy to obtain and the cost can be suppressed.

  The calculation unit 13 corrects the input temperature data Td based on the load data Pd, and successively estimates the true temperature Tr of the kneaded rubber material R. Correlation data for correcting the temperature data Td based on the load data Pd is input in advance to the calculation unit 13, and the true temperature Tr is estimated using this correlation data. Details of this correlation data will be described later.

  Although the control unit 12 and the calculation unit 13 are provided separately in this embodiment, the control unit 12 may be used as the calculation unit 13. That is, one computer may be configured to function as the controller 12 and the calculator 13.

  Next, an example of a procedure of kneading the rubber material R by the kneading method of the rubber material of the present invention will be described.

  In the kneading step, a predetermined amount of one batch of rubber material R (raw material G, non-vulcanizing compounding agent N, oil, etc.) is charged into the kneading chamber 5a of the kneading machine 1 of FIG. The kneading rubber RF is manufactured by kneading under a predetermined kneading condition (for example, controlling the rotation speed of the rotor 2, the ram pressure, the kneading time, etc.) so as to obtain the target viscosity. The volume of the rubber material R charged is, for example, 50% to 70% of the volume of the kneading chamber 5a.

  In the rubber mastication step (S1), as illustrated in FIG. 1, a predetermined amount of the raw material rubber G that has been set in advance is held in the rubber charging unit while the ram 6 is held at the standby position at the upper end of the ram chamber 5b. It is introduced into the kneading chamber 5a through 8. Then, the ram 6 is moved downward to the lower end of the ram chamber 5b. In this state, while the oil is being introduced into the kneading chamber 5a through the oil introducing section 7, the rotor 2 is rotationally driven to knead the raw rubber G and the oil.

  In the compounding agent taking-in step (S2), 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 introduced from the hopper 9. It is charged into the kneading chamber 5a through the section 10. Then, the ram 6 is moved downward to the lower end of the ram chamber 5b. In this state, as illustrated in FIG. 5, the rotor 2 is rotationally driven to knead the rubber material R.

  In the compounding agent taking-in step (S2), the compounding agent N placed on the rubber-kneaded raw material rubber G is largely stirred to gradually form a small rubber mass. Then, a small piece of rubber gradually grows and eventually becomes a lump. In the compounding agent intake step (S2), the ram 6 is raised several times to the upper end of the ram chamber 5b, and the rotor 2 is rotated to reverse the rubber material R upside down.

  In the uniform dispersion step (S3), the compounding agent N is uniformly dispersed throughout the raw material rubber G. When the uniform dispersion step (S3) is completed and the kneading process of the rubber material R for one batch is completed, the discharge door 11 is opened and the kneaded rubber RF is discharged from the bottom surface of the kneading chamber 5a. Thereafter, a similar kneading step is sequentially performed on a new rubber material R for one batch, and the rubber material R for a plurality of batches is continuously kneaded.

  In the contact-type temperature sensor 14, the temperature of the rubber material R is detected by the rubber material R coming into contact with the temperature sensor 14 (casing 14b). When the kneaded rubber material R is not in contact with the temperature sensor 14 (casing 14b), the temperature sensor 14 detects the temperature of the void (air) existing in the kneading chamber 5a. Since the temperature of the void is usually lower than the temperature of the rubber material R, if the kneaded rubber material R contacts the temperature sensor 14 less frequently, the temperature data Td detected by the temperature sensor 14 will be It becomes lower than the true temperature Tr of R.

  Further, the harder the rubber material R, the larger the load P acting on the temperature sensor 14 (casing 14b) by the kneaded rubber material R. The larger the load P, the larger the frictional heat generated between the temperature sensor 14 and the rubber material R. Due to this, the temperature data Td detected by the temperature sensor 14 becomes higher than the true temperature Tr of the rubber material R.

  6 illustrates the true temperature Tr of the kneaded rubber material R, the temperature data Td detected by the temperature sensor 14, and the load data Pd acting on the temperature sensor 14 detected by the load sensor 15 with time. It's a change. The load data Pd is displayed as a histogram, and the height of each pillar indicates the size of the load P, and the distance between adjacent pillars indicates the detection interval of the load P (frequency of occurrence of the load P).

  FIG. 6A shows the true temperature Tr, the temperature data Tr, and the load data Pd when the rotor 2 is rotated at a relatively low speed and the rubber material R having a relatively low hardness is kneaded. In this case, the magnitude of the load P acting on the temperature sensor 14 is relatively small, and the frequency of occurrence of the load P is low. Therefore, the true temperature Tr is higher than the temperature data Tr, and a difference m occurs between them. This difference m becomes a positive correction value when estimating the true temperature Tr.

  FIG. 6B shows the true temperature Tr, the temperature data Tr, and the load data Pd when the rotor 2 is rotated at a relatively high speed and the rubber material R having a relatively high hardness is kneaded. In this case, the magnitude of the load P acting on the temperature sensor 14 is relatively large, and the frequency of occurrence of the load P is high. Therefore, the temperature data Tr is higher than the true temperature Tr, and a difference m occurs between the two. This difference m becomes a negative correction value when estimating the true temperature Tr. The larger the calculated value obtained by multiplying the magnitude of the load P by the occurrence frequency, the larger the negative correction value m, and the smaller the calculated value, the larger positive correction value m.

  Therefore, in the present invention, for each specification of the rubber material R, the load data Pd acting on the temperature sensor 14 by the kneaded rubber material R (the magnitude and frequency of occurrence of the load P) is the temperature detected by the temperature sensor 14. The degree of influence on the data Td is known. That is, the correlation data between the load data Pd and the difference m (correction value m) is grasped by performing pre-kneading or the like. The grasped correlation data is input and stored in the calculation unit 13 in advance.

  In the series of kneading steps of S1 to S3, the temperature sensor 14 sequentially detects the temperature data Td and the load sensor 15 sequentially detects the load data Pd, and the temperature data Td and the load data Pd are sequentially input to the calculation unit 13. To be done. The calculation unit 13 sequentially estimates the true temperature Tr of the rubber material R using the temperature data Td, the load data Pd, and the correlation data that have been input in advance, which are input in sequence. The true temperature Tr of the rubber material R may be estimated only in the uniform dispersion step (S3).

  More specifically, in order to estimate the true temperature Tr at a certain time point t, the load data Pd detected in a predetermined time range (for example, 30 seconds to 60 seconds) immediately before the certain time point t and the correlation data described above. The correction value m is calculated using and. Then, the estimated value of the true temperature Tr is calculated by adding the calculated correction value m to the temperature data Td detected by the temperature sensor 14 at a certain time t (Tr = Td + m). In this way, the temperature data Td detected by the temperature sensor 14 is corrected based on the magnitude and frequency of the load P acting on the temperature sensor 14 arranged in the kneading chamber 5a, and the kneaded rubber material is thus corrected. Since the true temperature Tr of R is estimated, the true temperature Tr of the rubber material R can be grasped with high accuracy.

Using the estimated true temperature Tr, the control unit 12 controls the kneading conditions (rotation speed of the rotor 2, ram pressure, kneading time, etc.) so that the kneading rubber RF has a desired quality and performs kneading. .
Along with this, variations in the quality of the rubber material R during kneading are suppressed, which is advantageous for stably obtaining the kneading rubber RF of desired quality.

  The temperature sensor 14 can be installed not only on the upper surface of the discharge door 11 but also on the side surface of the kneading chamber 5a. Since the temperature sensor 14 is preferably installed in a place where the frequency of contact with the rubber material R is high, the upper surface of the discharge door 11 is a suitable installation place.

  The number of the temperature sensors 14 installed is not limited to one and may be plural. Therefore, it is possible to dispose the temperature sensors 14 on the upper surface of the discharge door 11 and the side surfaces of the kneading chamber 5a, or to dispose the temperature sensors 14 at a plurality of positions on the upper surface of the discharge door 11 and a plurality of positions on the side surfaces of the kneading chamber 5a. it can. When using a plurality of temperature sensors 14, it is desirable to arrange them at positions as distant from each other as possible.

  By installing the plurality of temperature sensors 14, the temperature data Td detected under the same condition increases, so that it becomes easier to estimate the true temperature Tr with higher accuracy. However, even if the number of installed temperature sensors 14 is three or more, the estimation accuracy of the true temperature Tr does not improve in accordance with the number of installed temperature sensors 14, so the number of installed units should be one or two. .

  When kneading the rubber material R mixed with silica and a silane coupling agent, the temperature of the rubber material R is strictly maintained at a predetermined temperature particularly in the uniform dispersion step (S3) to obtain a kneaded rubber RF having a predetermined quality. It can be manufactured stably. Therefore, applying the present invention is very beneficial.

  The present invention is applicable not only to the case where the raw rubber G is kneaded with the non-vulcanizing compounding agent N. For example, the kneaded rubber RF produced by kneading the raw material rubber G and the non-vulcanized compounding agent N (such as sulfur and vulcanization accelerator) and the vulcanized compounding agent N are kneaded to obtain the final kneaded rubber. It is also applicable when manufacturing RF.

  Seven kinds of rubber materials having different hardness were kneaded at the number of rotations of the rotor shown in Table 1 using the same kneading system as the kneading system illustrated in FIG. Table 1 shows the true temperature Tr of the rubber material just before the completion of the kneading, the temperature data Td of the rubber material detected by the temperature sensor, and the true temperature Tr (Tx) estimated using the same method as that of the present invention described above. Shown in.

  From the results of Table 1, it can be seen that the estimated temperature Tr (Tx) is closer to the true temperature Tr than the temperature data Td detected by the temperature sensor.

1 Closed Kneader 2 (2A, 2B) Rotor 2c Rotor Shaft 2d Stirring Blade 3 (3A, 3B) Drive Motor 4 Transmission 5a Kneading Chamber 5b Ram Chamber 6 Ram 7 Oil Feeding Section 8 Rubber Feeding Section 9 Hopper 10 Compounding Agent Input part 11 Discharge door 12 Control part 12a Power meter 12b Tachometer 13 Calculation part 14 Temperature sensor 14a Thermocouple 14b Casing 15 Load sensor (strain gauge)
G Raw rubber N Compounding agent R Rubber material RF Kneading rubber

Claims (4)

In a kneading chamber of a closed kneading machine, a rubber material composed of a raw rubber and a compounding agent is kneaded by rotating a rotor provided in the kneading chamber to knead a rubber material to produce a kneaded rubber of desired quality. In the method
The temperature of the rubber material being kneaded in the kneading chamber is detected by a temperature sensor arranged in the kneading chamber, and the magnitude and the occurrence frequency of the load acting on the temperature sensor are detected by a load sensor, The true temperature of the rubber material is estimated by correcting the temperature data detected by the temperature sensor based on the load data detected by the load sensor, and the estimated temperature is used to knead the rubber material. A method for kneading a rubber material, which is characterized in that   The method for kneading a rubber material according to claim 1, wherein a strain gauge installed on the temperature sensor is used as the load sensor.   The method for kneading a rubber material according to claim 1, wherein a plurality of the temperature sensors are arranged. A closed type kneader having a kneading chamber into which a rubber material composed of raw rubber and a compounding agent is charged, a rotor arranged in the kneading chamber, and a drive motor for rotationally driving the rotor, and the closed type kneader. In a kneading system for rubber materials, which comprises a control unit for controlling the movement of
A temperature sensor arranged in the kneading chamber for detecting the temperature of the rubber material kneaded in the kneading chamber, a load sensor for detecting the magnitude and frequency of occurrence of a load acting on the temperature sensor, and the temperature sensor The rubber material, the temperature data detected by the load sensor and the load data detected by the load sensor are input, and the temperature data is corrected by the calculation unit based on the load data. The true temperature of the rubber material is estimated, and the closed type kneading machine is controlled by the control unit using the estimated true temperature to knead the rubber material. Kneading system.

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