Mixer generally consists of an internal mixing chamber, two oppositely rotating rotors, an upper top bolt, and a lower top It consists of bolt, temperature measurement system, heating and cooling system, exhaust system, safety installation, discharge installation and recording installation. The surface of the rotor has helical protruding ribs, and the number of protruding ribs is two, four, six, etc. The cross-sectional geometry of the rotor is triangular, cylindrical or elliptical, and there are two types of tangential and meshing. . The temperature measurement system is composed of thermocouples, which are mainly used to measure the temperature change in the mixing chamber during the mixing process; the heating and cooling system is mainly used to control the temperature of the rotor and the outer surface of the mixing chamber cavity.

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1. Rotor speed: the faster the sub-speed, the greater the heat generation, the faster the oxidative cracking, the better the plasticizing effect, and the shorter the plasticizing time.

2. Temperature: The temperature rises, the thermal oxidation cracking is fast, and the plasticizing effect is good. However, if the temperature is too high, it will lead to excessive cracking of rubber molecules, resulting in a decrease in physical and mechanical properties. The debinding temperature of natural rubber is generally controlled at 140℃-160℃, and the temperature of styrene-butadiene rubber is controlled at 140℃. Because the temperature is too high, reactions such as cross-linking or branching will occur, which will reduce the plasticity. Generally, no internal mixer is used for plasticizing. At the mixing temperature, not only the plasticizing effect cannot be obtained, but it will lead to the formation of gel.

3. Time: The plasticity of the raw rubber increases with the increase of the plasticizing time in the internal mixer. Therefore, the formulation of rubber mixing conditions is mainly to determine the appropriate plasticizing time according to the requirements of plasticity.

4. The amount of glue loaded and the pressure of the top bolt: the amount of glue loaded is too small, and the plasticizing effect is low. Too large amount of glue will make the raw rubber plasticized unevenly, and the temperature of the glue will be too high. In addition, the equipment can be overloaded and easily damaged. During the plasticizing process of the internal mixer, the top bolt must pressurize the rubber material to ensure a good plasticizing effect. Within a certain range, the plasticizing effect increases with the increase of the top bolt pressure.