JP7684567B2 - Method and system for mixing unvulcanized rubber - Google Patents

Description

The present invention relates to a method and system for mixing unvulcanized rubber, and more specifically, to a method and system for mixing unvulcanized rubber that can more reliably produce unvulcanized rubber mixed with vulcanization-related compounding agents.

Various rubber products such as tires and conveyor belts are manufactured by vulcanizing unvulcanized rubber. This unvulcanized rubber contains raw rubber, non-vulcanization compounding agents, and vulcanization compounding agents. The procedure for manufacturing this unvulcanized rubber is, for example, to produce a primary kneaded rubber by kneading the raw rubber and non-vulcanization compounding agents. After that, the primary kneaded rubber is kneaded with the vulcanization compounding agents to produce unvulcanized rubber.

Various open-structure roll mixers have been proposed as devices for mixing unvulcanized rubber (see, for example, Patent Document 1). When the primary mixed rubber and vulcanization compounding agents are mixed using an open-structure roll mixer, the vulcanization compounding agents are added to a lump or sheet-like raw rubber material, which is then fed into the circulation path through which the primary mixed rubber circulates. At this time, problems may occur in which the vulcanization compounding agents are not reliably fed into the circulation path, for example, because the raw rubber material bounces around and falls off the circulation path. Therefore, there is room for improvement in order to more reliably produce unvulcanized rubber mixed with vulcanization compounding agents.

JP 2006-142802 A

The object of the present invention is to provide a method and system for kneading unvulcanized rubber that can more reliably produce unvulcanized rubber kneaded with vulcanization-related compounding agents.

In order to achieve the above object, the unvulcanized rubber mixing method of the present invention is a method for producing unvulcanized rubber by circulating and kneading a primary kneaded rubber, in which a non-vulcanized compounding agent is mixed with raw rubber, and a vulcanization compounding agent through a circulation path of an open-structure roll kneader, the method being characterized in that a master batch in which the vulcanization compounding agent is colored a different color from the primary kneaded rubber is prepared, the master batch is introduced into the circulation path in which the primary kneaded rubber circulates, color data on the surface of the circulation path is detected at a predetermined position in the extension direction of the circulation path by a non-contact color identification sensor, and a calculation device determines the appropriateness of the introduction of the vulcanization compounding agent into the primary kneaded rubber based on the detected color data.

The unvulcanized rubber mixing system of the present invention is an unvulcanized rubber mixing system equipped with an open-structure roll mixer having a circulation path that circulates and mixes a primary kneaded rubber in which non-vulcanized compounding agents are mixed with raw rubber and vulcanized compounding agents, and is characterized in that it has a non-contact color identification sensor that detects color data on the surface of the circulation path at a predetermined position in the extension direction of the circulation path, and a calculation device to which the color data is input, and a master batch colored in a color different from the primary kneaded rubber is used as the vulcanized compounding agent, and the calculation device determines the appropriateness of the addition of the vulcanized compounding agent to the primary kneaded rubber based on the color data detected by the color identification sensor.

According to the present invention, a master batch is used in which the vulcanization compounding agent is colored a different color from the primary kneaded rubber, so the color data detected by the color identification sensor is different when the vulcanization compounding agent is properly added to the primary kneaded rubber from when it is not properly added. Therefore, based on the detected color data, the calculation device can accurately determine the appropriateness of adding the vulcanization compounding agent to the primary kneaded rubber. As a result, it is advantageous to more reliably produce unvulcanized rubber kneaded with the vulcanization compounding agent.

1 is an explanatory diagram illustrating an embodiment of a system for kneading unvulcanized rubber in a side view. FIG. 2 is an explanatory diagram illustrating a state in which the produced unvulcanized rubber is discharged from the roll mixer of FIG. 1. [0023] FIG. 2 is an explanatory diagram illustrating a schematic plan view of the periphery of a detection range of the color discrimination sensor of FIG. 1 ; 2 is an explanatory diagram illustrating a schematic plan view of the periphery of the detection range of a color identification sensor after a master batch is introduced into the roll mixer of FIG. 1 ; FIG. 10 is a graph diagram illustrating a schematic example of a change over time in detection intensity of color data in a detection range detected by a color discrimination sensor; FIG. 2 is a graph illustrating index data for understanding the state of kneading of vulcanization compounding ingredients.

The unvulcanized rubber mixing method and mixing system of the present invention will be described below based on the embodiment shown in the figure.

In the embodiment of the unvulcanized rubber kneading system 1 of the present invention illustrated in Figures 1 to 3, a primary kneaded rubber R1, in which raw rubber M1 is kneaded with non-vulcanized compounding agent M2, is kneaded with vulcanized compounding agent M3 to produce unvulcanized rubber R. The raw rubber M1, non-vulcanized compounding agent M2, and vulcanized compounding agent M3 that make up the unvulcanized rubber R are each used in a preset blend amount.

The raw rubber M1 is one or more types of natural rubber or various synthetic rubbers, depending on the purpose. The non-vulcanization compounding agent M2 is appropriately selected from various known compounding agents such as carbon black and silica, depending on the purpose. The vulcanization compounding agent M3 is appropriately selected from various known compounding agents such as sulfur, vulcanization activators, and vulcanization accelerators, depending on the purpose.

The primary mixed rubber R1 is obtained by mixing raw rubber M1 and non-vulcanized compounding agent M2. The primary mixed rubber R1 may be mixed using this roll mixer 2 or another mixer (such as a Banbury mixer).

In this embodiment, the vulcanization compounding agent M3 is used in the form of a master batch Mb that is colored in a color different from the primary mixed rubber R. That is, to prevent the powdered vulcanization compounding agent M3 from scattering, a master batch Mb is used that is manufactured by pre-kneading the raw rubber M1, the vulcanization compounding agent M3, and the coloring agent.

It is preferable to set the color of the master batch Mb to a color that is easily distinguishable from the color of the primary kneaded rubber R1. Since the primary kneaded rubber R1 is generally black, it is preferable to set the color of the master batch Mb to white, red, yellow, blue, etc.

The kneading system 1 includes an open-structure roll kneader 2, a non-contact color identification sensor 9, and a computing device 10. The kneading system 1 further includes a display 11 and a warning device 12. The display 11 and warning device 12 can be provided as desired.

The roll mixer 2 has a circulation path that circulates and mixes the primary mixed rubber R1 and the vulcanization compounding agent M3. As the roll mixer 2, various known open structures can be used. This roll mixer 2 is equipped with a pair of opposing mixer rolls 2a, 2b, a mixer conveyor 5, a delivery conveyor 6, a supply conveyor 7, and a control device 8.

The pair of kneading rolls 2a, 2b are rotated by hydraulic or electric drive motors 4a, 4b provided separately, and the rotation speeds of the kneading rolls 2a, 2b can be adjusted independently, and they can rotate forward and backward. One of the kneading rolls, 2a, is connected to an actuator 3 such as a hydraulic cylinder, and the gap (roll gap) between the kneading rolls 2a, 2b can be adjusted by moving the kneading roll 2a toward and away from the other kneading roll 2b.

The kneading conveyor 5 extends horizontally from above the pair of kneading rolls 2a, 2b, and its extension direction changes diagonally downward along the way. The delivery conveyor 6 extends horizontally from below the pair of kneading rolls 2a, 2b, and is capable of rotating up and down along the way. The end of the kneading conveyor 5 that extends diagonally downward is located around the rotation center of the delivery conveyor 6.

As shown in FIG. 1, when the transfer conveyor 6 rotates upward midway, a circulation path is formed by the kneading conveyor 5 and the transfer conveyor 6. As shown in FIG. 2, when the transfer conveyor 6 rotates downward midway and becomes flat over its entire length, the circulation path is eliminated.

The supply conveyor 7 is disposed above the pair of kneading rolls 2a, 2b. The strip-shaped master batch Mb (vulcanization compounding agent M3) transported by the supply conveyor 7 is fed between the pair of kneading rolls 2a, 2b. The kneading conveyor 5, the delivery conveyor 6, and the supply conveyor 7 may each be a known conveyor device. The transported object is placed on the upper surface of the conveyor belt provided on each of these conveyors and transported.

The operation of the pair of kneading rolls 2a, 2b (drive motors 4a, 4b), actuator 3, kneading conveyor 5, delivery conveyor 6, and supply conveyor 7 is controlled by a control device 8. Data on the drive torque of the drive motors 4a, 4b, the surface speed of the kneading rolls 2a, 2b, the roll gap, and the rubber temperature are input to the control device 8, and the control device 8 controls these kneading conditions based on this data.

The color identification sensor 9 detects color data on the surface of the circulation path at a predetermined position in the extension direction of the circulation path formed by the kneading conveyor 5 and the delivery conveyor 6. As the color identification sensor 9, various known devices that can identify the color (color difference) of the detection range Z in a non-contact state with the detection range Z can be used.

In this embodiment, the predetermined position where the color identification sensor 9 is placed is set above the horizontally extending portion of the kneading conveyor 5. At this predetermined position, the color identification sensor 9 detects color data on the upper surface of the conveyor belt of the kneading conveyor 5, which constitutes the circulation path. The predetermined position where the color identification sensor 9 is placed is not limited to this position, and may be above the delivery conveyor 6.

As shown in FIG. 3, in this embodiment, two color identification sensors 9 are disposed above the re-kneading conveyor 5. In the drawing, the detection range Z of each color identification sensor 9 is depicted as an area surrounded by a dashed line. It is preferable that the color identification sensor 9 detects color data by covering the entire width of the circulation path at the designated position where it is disposed. In other words, it is preferable to set the detection range Z so as to cover the entire width of the circulation path (the upper surface of the belt conveyor). If it is possible to set the detection range Z so that one color identification sensor 9 covers the entire width of the circulation path (the upper surface of the belt conveyor), then only one color identification sensor 9 may be disposed, but if this is not possible, the required number of color identification sensors 9 are disposed in a line in the width direction of the circulation path.

The color discrimination sensor 9 of this embodiment acquires image data of the detection range Z and identifies colors (color differences) by analyzing the image data. A color discrimination sensor 9 of a type that identifies colors (color differences) in the detection range Z by utilizing the wavelength (band) of reflected light in the detection range Z may also be used.

The color data detected by the color identification sensor 9 is input to the calculation device 10. A computer is used for the calculation device 10. The color data of the master batch Mb is stored in advance in the calculation device 10. It is preferable that color data of the primary kneaded rubber R1 and the surface of the circulation path of the detection range Z (the upper surface of the conveyor belt) is also stored in advance in the calculation device 10. The calculation device 10 judges the suitability of adding the vulcanization compounding agent M3 to the primary kneaded rubber R based on the color data input from the color identification sensor 9.

The display 11 displays data input to the computing device 10, data that has been processed, etc. The display 11 can also function as a warning device 12, which will be described later.

The warning device 12 operates based on a determination made by the computing device 10. Examples of the warning device 12 include warning lights, alarms, and various devices that display warnings.

Next, an example of the procedure for producing unvulcanized rubber R according to the present invention will be described.

As shown in FIG. 1, the master batch Mb is fed onto a pair of kneading rolls 2a, 2b of the roll kneader 2 by a supply conveyor 7. In this roll kneader 2, the primary kneaded rubber R circulates along a circular circulation path formed by a kneading conveyor 5 and a delivery conveyor 6.

The master batch Mb fed into this circulation path repeatedly circulates through the circulation path together with the primary kneaded rubber R1. In the circulation path, the primary kneaded rubber R1 and the master batch Mb are subjected to an appropriate shear force by passing between the kneading rolls 2a and 2b, which rotate in opposite directions, and being pressed. By repeatedly applying shear force through the kneading rolls 2a and 2b, the vulcanization compounding agent M3 is gradually dispersed over a wide area in the primary kneaded rubber R1, while the primary kneaded rubber R1 and the master batch Mb are kneaded to produce unvulcanized rubber R with the target viscosity.

When the unvulcanized rubber R is produced, as shown in FIG. 2, the middle of the delivery conveyor 6 is rotated downward to eliminate the circulation path. The produced unvulcanized rubber R is then discharged from the roll kneader 2 by the delivery conveyor 6 and transported to the next process.

In the present invention, while the primary mixed rubber R1 and the master batch Mb are being mixed, the color identification sensor 9 detects color data on the surface of the circulation path. As illustrated in FIG. 3, before the master batch Mb is fed into the circulation path, only the primary mixed rubber R1 is present on the surface of the circulation path. Therefore, the color data detected by the color identification sensor 9 is mainly the color data of the primary mixed rubber R1, and some color data of the surface of the conveyor belt is also detected. However, the color data of the master batch Mb is not detected.

The color data of the master batch Mb is stored in advance in the calculation device 10. Furthermore, the color of the master batch Mb is different from that of the primary mixed rubber R. When the color data detected by the color identification sensor 9 is input to the calculation device 10, the input color data is compared with the stored color data of the master batch Mb to calculate the degree of match between the two. As a result, the degree of match between the two is calculated to be low, so it is determined that the master batch Mb is not present in the detection range Z. In other words, it is determined that the vulcanization compounding agent M3 is not mixed into the primary mixed rubber R1.

As shown in FIG. 4, after the master batch Mb is introduced into the circulation path, the primary kneaded rubber R1 and the master batch Mb are present on the surface of the circulation path. Therefore, the color data detected by the color identification sensor 9 changes mainly to the color data of the primary kneaded rubber R1 and the color data of the master batch Mb.

When the color data detected by the color identification sensor 9 is input to the calculation device 10, the input color data is compared with the stored color data of the master batch Mb to calculate the degree of match between the two. As a result, the degree of match between the two is calculated to be high, so it is determined that the master batch Mb is present in the detection range Z. In other words, it is determined that the vulcanization compounding agent M3 is kneaded into the primary kneaded rubber R1.

Therefore, immediately after the master batch Mb is fed into the roll mixer 2 by the feed conveyor 7, the color identification sensor 9 detects the color data on the surface of the circulation path. This makes it possible to determine the appropriateness of the feeding of the vulcanization compounding agent M3 to the primary mixed rubber R1 (whether it has been fed reliably or not) based on the color data detected by the color identification sensor 9.

Even if the master batch Mb (vulcanization compounding agent M3) is reliably added to the primary mixed rubber R1, as the mixing of the primary mixed rubber R1 and the master batch Mb progresses, the pigment of the master batch Mb disperses widely in the primary mixed rubber R1, and the color data of the master batch Mb gradually becomes undetectable. That is, as illustrated in Figure 5, the detection intensity of the color data of the master batch Mb gradually decreases. In Figure 5, the change in the detection intensity D of this color data is simplified and depicted as decreasing linearly.

Therefore, in order to accurately determine the appropriateness of adding the vulcanization compounding agent M3 to the primary mixed rubber R1, it is necessary to use color data detected within a relatively short period (small number of circulations) that is set in advance from the start of the operation of adding the master batch Mb to the roll mixer 2. The appropriate value for this relatively short period (small number of circulations) is determined by prior mixing using the roll mixer 2, etc.

In this way, according to the present invention, a master batch Mb in which the vulcanization compounding agent M3 is colored a different color from the primary mixed rubber R1 is used, and based on the color data detected by the color identification sensor 9, it is determined whether the vulcanization compounding agent M3 has been added to the primary mixed rubber R. This allows for accurate determination, which is advantageous for more reliably producing unvulcanized rubber R kneaded with the vulcanization compounding agent M3.

In addition, color data is detected non-contact using a color identification sensor 9 for the primary mixed rubber R1 and master batch Mb circulating through the circulation path. This is therefore advantageous for efficient production without impairing the productivity of the unvulcanized rubber R.

The master batch Mb may be mixed into the primary mixed rubber R1 in a state where it is unevenly distributed in the width direction. Therefore, as in this embodiment, detecting color data covering the entire width range of the circulation path at a specified position is advantageous for determining with high accuracy the appropriateness of adding the vulcanization compounding agent M3 to the primary mixed rubber R1.

In this embodiment, the color identification sensor 9 detects color data in a flat area of the circulation path. That is, the detection range Z is set in the flat area of the conveyor belt, but the detection range Z can also be set, for example, in a curved area around the pulley of the belt conveyor. In such a curved area of the circulation path, the circulating rubber material is pulled relatively strongly, and it may be possible to detect the color inside the rubber material. Therefore, it becomes possible to detect the color data of the master batch Mb embedded in the primary kneaded rubber R1.

When using multiple types of vulcanization compounding agents M3, it is advisable to prepare and use master batches Mb colored in different colors for each type. This allows the color identification sensor 9 to identify and detect the color data of each master batch Mb, making it possible to determine the appropriateness of adding each type of vulcanization compounding agent M3 to the primary mixed rubber R1. In this case, it is preferable to set the color of each master batch Mb to an easily distinguishable color.

When the display 11 is provided, the image data of the detection range Z and the detection intensity D of the color data input to the calculation device 10 can be displayed on the display 11 in real time. This makes it easier to grasp the mixing state of the primary mixed rubber R1 and the master batch Mb just by looking at the display 11.

If the calculation device 10 determines that the addition of the vulcanization compounding agent M3 to the primary kneaded rubber R1 is inappropriate, the warning device 12 issues a warning to notify the user of the inappropriateness. If the display 11 is configured to display a warning to notify the user of this, the display 11 functions as the warning device 12. By providing the warning device 12, the occurrence of a malfunction can be detected without delay, allowing for prompt countermeasures to be taken.

The degree of mixing of the vulcanization compounding agent M3 with the primary mixed rubber R1 can also be determined by using the change over time in the detection intensity D of the color data shown in Figure 5. This detection intensity D gradually decreases when the master batch Mb (vulcanization compounding agent M3) is reliably added to the primary mixed rubber R1.

Therefore, data on the change over time of the detection intensity D when the master batch Mb (vulcanization compounding agent M3) is properly added to and kneaded with the primary kneaded rubber R1 to produce a good unvulcanized rubber R is used as index data Dm, as illustrated in FIG. 6. An allowable range Ar is set for this index data Dm. Then, the data on the change over time of the detection intensity D obtained when kneading the primary kneaded rubber R1 and the master batch Mb (vulcanization compounding agent M3) is compared with the index data Dm in FIG. 6. If, as a result of the comparison, the obtained data on the change over time of the detection intensity D falls within the allowable range Ar of the index data Dm in FIG. 6, it can be determined that the kneading state is good.

REFERENCE SIGNS LIST 1 Kneading system 2 Roll kneaders 2a, 2b Kneading rolls 3 Actuators 4a, 4b Driving motors 5 Kneading conveyor 6 Delivery conveyor 7 Supply conveyor 8 Control device 9 Color identification sensor 10 Calculation device 11 Display 12 Warning device R Unvulcanized rubber R1 Primary kneaded rubber M1 Raw rubber M2 Non-vulcanized compounding agent M3 Vulcanized compounding agent Mb Master batch

Claims (6)

In a method for kneading unvulcanized rubber, a primary kneaded rubber obtained by kneading a raw rubber with a non-vulcanization compounding agent and a vulcanization compounding agent are circulated through a circulation path of an open-structure roll kneader to produce an unvulcanized rubber,
A method for kneading unvulcanized rubber, comprising the steps of: preparing a master batch in which the vulcanization compounding agents are colored a color different from that of the primary kneaded rubber; introducing the master batch into the circulation path through which the primary kneaded rubber circulates; detecting color data on the surface of the circulation path at a predetermined position in the extension direction of the circulation path using a non-contact color identification sensor; and using a calculation device to determine the appropriateness of the introduction of the vulcanization compounding agents into the primary kneaded rubber based on the detected color data. The method for kneading unvulcanized rubber according to claim 1, wherein the color data is detected over the entire width of the circulation path at the specified position. The method for kneading unvulcanized rubber according to claim 1 or 2, wherein the degree of mixing of the vulcanization compounding agent with the primary kneaded rubber is determined based on the change over time in the color data. The method for kneading unvulcanized rubber according to any one of claims 1 to 3, wherein the master batches are prepared in different colors according to the type of vulcanization compounding agent. The method for kneading unvulcanized rubber according to any one of claims 1 to 4, wherein the computing device issues a warning to inform of the occurrence of a problem if it determines that the addition of the vulcanization compounding agent to the primary kneaded rubber is not appropriate. In a kneading system for unvulcanized rubber, the system includes an open-structure roll kneader having a circulation path for circulating and kneading a primary kneaded rubber obtained by kneading a raw rubber with a non-vulcanization-based compounding agent and a vulcanization-based compounding agent,
A system for kneading unvulcanized rubber, comprising: a non-contact color identification sensor that detects color data on the surface of the circulation path at a predetermined position in the extension direction of the circulation path; and a calculation device to which the color data is input, wherein a master batch colored a different color from the primary kneaded rubber is used as the vulcanization-system compounding agent, and the calculation device is configured to determine the appropriateness of the addition of the vulcanization-system compounding agent to the primary kneaded rubber based on the color data detected by the color identification sensor.

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