KR100520110B1 - Method for controlling a blending and mixture of rubber in an internal mixer - Google Patents

Abstract

The present invention is a method for controlling the mixing degree of the rubber when the chemical and the rubber is blended or mixed with the rubber during the rubber manufacturing process, the rubber is manufactured using an internal mixer (internal mixer) It relates to a mixing control method of rubber that can be usefully applied.

That is, the present invention includes the steps of setting a temperature value control amount which is a 150 ° C. target mixing temperature for controlling the mixing degree of rubber in a hermetic mixer for rubber mixing with a thermometer 12 which is a conventional device for detecting temperature;

In the initial stage of mixing, the motor RPM values input sequentially are outputted to the motor in the initial stage, and the comparison and calculation are performed to reach the control temperature target of 150 ℃ according to the temperature rise by rubber mixing. step;

The control system function is used to convert the control temperature target control (temperature 150 ℃) and the electric signal output to the thermometer 12 to read the actual output value temperature Y (t), and to control the control temperature target control (temperature 150 ℃) and the measured value. Using the calculation and calculation of the deviation of the;

Outputting the newly calculated output signal RPM value U (t) from the motor, and comparing the obtained temperature output value Y (t) again to output another output signal RPM value U (t) to the motor Performing;

Characterized in that the mixing is terminated when the end point of mixing is equal to or greater than the release reaction amount.

Description

Method for controlling a blending and mixture of rubber in an internal mixer

The present invention relates to a method for controlling the mixing of rubber, and more particularly, to control the mixing of the rubber when blending (Bixing) or mixing only the rubber (Bixing) by adding a chemical and rubber during the rubber manufacturing process The method relates to a mixing control method of rubber which can be usefully applied when rubber is manufactured using an internal mixer.

In general, mixers have different characteristics for each manufacturer, but they are manufactured by adopting time, integrated power, and temperature as control variables to control the degree of mixing, but most of them use time, power, and temperature.

The time control method of the conventional mixer is slightly different from the physical properties of the raw rubber used, and in particular, when using a natural rubber product, the viscosity and molecular weight of the rubber is different, so that only one controlled amount is used to obtain the desired physical properties. Not only is it difficult to achieve, but due to the structural characteristics of the hermetic mixer, the mechanical work is changed by the slippage phenomenon caused by the mixing of raw materials and chemicals, and as a result, the total work performed by the fluid (for example, rubber) is different. Since the viscosity of the rubber produced, the variation of the physical properties, etc. are very severe.

To solve these shortcomings and combine the integrated power used by integrating the torque value coming from the power recorder at the control time in order to manufacture rubber with more uniform physical properties, or use the control power as time and temperature. The mixing control method to control the system is adopted, developed and adopted in the mixer.

In addition to the mixing control method described above, there is a temperature controlled mixing method in which the control amount is changed to temperature. FIG. 1 is a schematic cross-sectional view of a mixer for mixing rubber, and reference numeral 11 is a rotor and reference numeral 12. Denotes a thermometer, and reference numeral 13 denotes a ram weight. As shown in FIG. 1, a thermometer 12 is inserted into a specific portion of the mixer, and the thermometer 12 detects a temperature appearing during mixing, and this is an electrical signal. When the signal is sent to the computer, there is a method of controlling the mixing to be terminated when it is equal to or larger than the set temperature which is the control amount at which the mixing ends.

When rubber is manufactured, the mixing temperature is very different from the atmosphere or the surrounding temperature such as winter and summer, or the temperature difference occurs in the continuous manufacturing process.Therefore, the response time required for the control shows a large difference. It acts as a deterrent. In other words, the mechanical work produced by the rotation of the rotor is converted into thermal energy, and the rubber having a high viscosity is higher in temperature rise rate than the rubber having a low viscosity.

For example, even if the temperature control amount is equal to 150 ° C., as shown in FIG. 2, which is a graph showing the change in the temperature curve and the control value, the heat state or the rate of temperature rise (path) generated by the seasonal change or the viscosity difference of the rubber The degree of will be different.

As shown in FIG. 2, a change in the path or speed of temperature means that a change in the amount of heat input to the rubber from the mixer occurs. Some rubber mixtures cause direct chemical reactions, in which case the temperature levels as well as the control of the chemical reactions are limited.

In the conventional temperature control system, a separate control method for suppressing the temperature limit is not configured. (Table 1) In the case of an AC motor using AC as a power source

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Mixing method Temperature Action Temperature Motor RPM Cleaning of rubber, chemicals and oils 80 ℃ 120 ℃ 150 ℃ 175 ℃ 70707070

(Table 2) In case of DC motor or AC inverter

Mixing method Temperature Action Temperature Motor RPM Cleaning of rubber, chemicals and oils 80 ℃ 120 ℃ 150 ℃ 175 ℃ 70604040

In the case of DC motors using direct current as shown in (Table 2), unlike AC motors using AC as shown in (Table 1), acceleration and deceleration of RPM are possible, so the time to reach the same temperature becomes longer when decelerating. As a result, a different characteristic can be obtained (lower heat generation rate).

Similar characteristics are found in systems employing AC inverters. However, if a particular rubber mixture has a characteristic of mixing for a certain time while maintaining the temperature of 160 ° C., the conventional method is as follows. In consideration of the exothermic rate appearing for each rubber characteristic, according to a predetermined order (i.e., sequential control). There is a way to work by specifying the speed in advance.

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However, even in such a method, as described above, since the behavior is very different according to seasonal factors or changes in material properties, a predetermined RPM of the rotor may need to be changed.

In addition, no matter how the speed is reduced, it is difficult to maintain a constant temperature according to the self-heating and latent heat of the mixture, and thus shows a very unstable temperature curve behavior such as gradually increasing or decreasing the target temperature as shown in FIG. 3.

In the prior art, when such a phenomenon occurs, the degree of chemical reaction of the material (polymerization degree, reaction rate), etc. is changed, which not only has a great influence on the quality, but also when the compounding design is changed, the exothermic rate is measured and adjusted appropriately. You need to create a control RPM. In addition, it is very difficult to solve this problem because the temperature is continuously increased or decreased by latent heat or external variables.

Accordingly, an object of the present invention is to solve the disadvantages of the prior art and to provide a new mixing control method of rubber for improving the quality of the rubber mixture.

That is, the present invention comprises the steps of setting a target temperature of control temperature, the target mixing temperature of 150 ℃ for controlling the mixing degree of the rubber in the hermetic mixer for rubber mixing with a thermometer 12 which is a conventional device for detecting the temperature;

The motor RPM values input sequentially at the beginning of mixing, and output the motor RPM values sequentially input to the motor at the beginning of the mixing, and compare and calculate whether the rubber reaches the 150 ℃ control temperature target according to the temperature rise by rubber mixing. step;

The control system function is used to convert the control temperature target amount R (t) (e.g. 150 ° C) and the electrical signal output from the thermometer 12 to read the actual output value temperature Y (t), and to control the control temperature target amount (150 ° C). Using for calculation and deviation of values;

Repeatedly outputting the newly calculated output signal U (t) to the motor, comparing again the obtained output value Y (t) and outputting another output signal U (t) to the motor;

Characterized in that the step of terminating the mixing when the temperature or time reaches a predetermined end point by the above step.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

According to the method of the present invention, the control temperature target amount (150 ° C.) is set to a target mixing temperature for controlling the mixing degree of the rubber in a hermetic mixer for rubber mixing with a conventional apparatus for detecting temperature.

At this time, the control amount derivation means detects from the electric signal converted using the thermometer 12 attached to the hermetic mixer, and sets the temperature control target amount to the control start temperature value at which control starts.

Next, the motor RPM value input in the sequential form at the beginning of mixing is outputted to the motor, and comparison and calculation are performed to reach the control start temperature according to the temperature rise during rubber mixing.

In the present invention, the basic logic for controlling uses the transfer function of the conventional PID controller as shown in FIG.

In FIG. 5, R (t) is a desired output value (control temperature target 150 ° C.), e (t) is a tracking error, and Y (t) is an actual output value. H (s) is a controller, G (s) is a motor, and u (t) is a signal output from the controller.

As shown in FIG. 5, the tracking error e (t) is the difference between the desired output value R (t) and the actual output value Y (t). The error signal e (t) is sent to the PID controller H (s), and the controller H (s) calculates the derivative value and the integral value of the error signal e (t). The signal u (t) output from the controller H (s) is the sum of the error multiplied by the proportional gain Kp, the integral of the error multiplied by the integral gain Ki, and the derivative of the error multiplied by the derivative gain Kd. Is calculated, i.e.

Thus, the signal u (t) is sent to the motor device, and a new output Y (t) is obtained. The new output Y (t) is fed back to calculate a new error signal e (t), and the controller calculates a new signal u (t) based on the new error signal e (t). This process is repeated in real time until the target amount is reached.

According to the present invention, the two-way communication may be configured to set or change a control target value in a PC or a programmable logic controller (PLC) rather than a PID controller as the control logic of the RPM.

According to the method of the present invention, the control function is used to convert the control target amount and the electric signal output from the thermometer to read the actual output value Y (t), and calculate the deviation and the accumulated accumulation amount of the target amount and the control value.

The output signal U (t) newly calculated from the above is output to the motor, and the output value Y (t) is again compared, and another output signal U (t) is outputted to the motor.

By the above steps, the mixing is terminated when the temperature, time or the like reaches a predetermined end point. In this case, the mixing uses a value in which an end point is set in advance, and this value may use a time or a specific control parameter value. In the present invention, a reaction amount that accumulates the reaction rate in a certain time for effective control of the chemical reaction. Use the parameters of.

Where the reaction rate is It can be expressed as a temperature value, that is, a gas constant value, which is converted into active energy and absolute temperature according to the Arrhenius relation.

And the reaction amount It is expressed as an integrated value of the difference in reaction rate for each time change.

In the present invention, the PID function is used for temperature control, and may be configured to interlock with a controller such as a temperature controller to adjust the RPM of the motor and the ram weight and the cooling water temperature of the mixer.

Figure 4 of the accompanying drawings is a flow chart for showing a series of processes for explaining the processing method of the mixing control program of the rubber according to the present invention, for example, first set the target control temperature and the control start temperature to 150 ℃, respectively And release reaction amount is set to 200. The current temperature is then read and compared with the control start temperature. It outputs the result of the current rpm and reaction amount, and transfers the existing control right to the computing unit the next time the control start temperature is reached.

Next, the new rpm control amount is output and controlled according to the calculation function, and the new control amount is continuously output compared with the target temperature. When the discharge reaction amount is reached in comparison with the discharge reaction amount set at the initial stage, mixing is terminated and discharged.

The following Table 3 compares the maximum torque values of the vulcanometer rheometers according to the conventional method and the control method of the present invention (Table 3).

Prior Art (Tmax) Invention (Tmax) Experimental Example 1 23.35 23.51 Experimental Example 2 25.31 23.55 Experimental Example 3 26.15 23.39 Experimental Example 4 27.7 24.16 Experimental Example 5 24.7 24.53 medium 25.442 23.828 Deviation 1.623597857 0.493274771 range 4.35 1.14 Coefficient of variation 6.38 2.07

※ Reduction rate of vulcanization degree of rubber mixture: 68%

6A and 6B of the accompanying drawings are graphs showing the dynamic characteristics of the prior art and the present invention.

FIG. 6A shows that the chemical reactivity of the sample is changed due to inaccurate mixing temperature, and thus the variation in the degree of vulcanization of the sample is large when it is controlled by a preset rpm value as a vulcanization degree curve of the sample prepared according to the prior art. Can be.

6b is automatically variable control rpm to maintain a constant temperature in the vulcanization curve of the sample mixed by the method of the present invention, the chemical reaction of the sample by the uniform temperature at the time of mixing is less uniform variation in the vulcanization degree of the sample The uniformity of the mixture is greatly improved.

According to the present invention, during the rubber manufacturing process, for example, a rubber composition including a silica composition and a silane composition is mixed by using a mixer, chemicals and rubber may be added or blended with only rubber. In this case, as a method for controlling the mixing degree of rubber, it can be usefully applied when manufacturing rubber by using an internal mixer, and manufacturing a high quality mixed rubber without variation of rubber viscosity or physical properties. can do.

1 is a cross-sectional view of a conventional rubber mixing mixer,

2 is a graph showing changes and control values of a conventional temperature curve;

3 is a graph showing the behavior of the temperature curve according to the RPM of a conventional motor,

4 is a control flowchart illustrating a series of procedures for explaining a method for controlling mixing of rubber according to the present invention;

5 is a diagram illustrating a conventional PID control system.

6 (a) and 6 (b) are graphs showing the dynamic characteristics of the prior art and the technology of the present invention.-Explanation of the symbols for the main parts of the drawing-11 Rotor, 12 Thermometer, 13 Ram weight (Ram Weight).

Claims (3)

Setting a temperature value control amount which is a 150 ° C. target mixing temperature for controlling the mixing degree of the rubber in the hermetic mixer for rubber mixing with a thermometer 12 which is a conventional device for detecting temperature; In the initial stage of mixing, the motor RPM values input sequentially are outputted to the motor in the initial stage, and the comparison and calculation are performed to reach the control temperature target of 150 ℃ according to the temperature rise by rubber mixing. step; The control system function is used to convert the control temperature target control (temperature 150 ℃) and the electric signal output to the thermometer 12 to read the actual output value temperature Y (t), and to control the control temperature target control (temperature 150 ℃) and the measured value. Using the calculation and calculation of the deviation of the; Outputting the newly calculated output signal RPM value U (t) from the motor, and comparing the obtained temperature output value Y (t) again to output another output signal RPM value U (t) to the motor Performing; And the step of terminating the mixing when the end point of mixing is equal to or greater than the release reaction amount by the step. The rubber mixing control method according to claim 1, wherein the mixer is configured to enable two-way communication so as to set or change a control target value in a PC or PLC other than the PID controller as the control logic of the RPM. . The rubber of claim 1, wherein the PID function is used to control the temperature, and is configured to interlock with a controller such as a temperature controller to adjust the RPM of the motor and the cooling water temperature of the ram weight and the mixer. Mixing control method.