110L internal mixer pressurized rear projection internal mixer

During mixing in an internal mixer, the order and mixing time of adding raw rubber, carbon black and liquid softener are particularly important. Generally, raw rubber is added first, then carbon black is added, and the mixture is mixed until the carbon black is basically in the rubber compound. Add liquid softener after dispersion, which is beneficial to mixing, improves mixing effect and shortens mixing time. Adding liquid softener too early or too late is detrimental to mixing and can easily lead to uneven dispersion, prolonged mixing time, and increased energy consumption. The addition time of liquid softener can be determined by the distribution coefficient. Sulfur and ultra-fast accelerator are usually added at the later stage of mixing, or discharged to the tablet press to reduce the risk of scorch. Small chemicals (solid softeners, activators, accelerators, anti-aging agents, anti-scorch agents, etc.) are usually added after raw rubber and before carbon black.
Upper ejector pressure
When mixing in an internal mixer, the rubber material must be subjected to a certain amount of pressure from the upper ejector pin. It is generally believed that the upper ejector pressure should be at. When the rotor speed is constant, further increasing the pressure has little effect. When the mixing capacity is insufficient, the upper ejector pressure cannot fully exert its effect. Increasing the upper ejector pressure can reduce the unfilled space in the closed chamber and increase its filling degree by approx. As the capacity and rotational speed increase, the pressure on the top bolt must be increased.
Increasing the pressure of the upper ejector will accelerate the heat generation of the rubber material during the mixing process and increase the power consumption during mixing.
Rotor structure and type
The geometry and size of the rotor working surface determine to a large extent the production capacity and mixing quality of the internal mixer. There are two basic configurations of internal mixer rotors: shear rotors and meshing rotors. Generally speaking, shear-type rotor internal mixers have higher production efficiency and can quickly feed, mix and discharge glue quickly. The meshing rotor internal mixer has the characteristics of high dispersion efficiency and low heat generation rate, and is suitable for manufacturing hard rubber materials and one-stage mixing. The dispersing and homogenizing effect of the meshing rotor internal mixer is better than that of the shearing rotor internal mixer, and the mixing time can be shortened by 3~.
Speed
Increasing the speed of the internal mixer rotor is one of the most effective measures to enhance the mixing process. Doubling the rotation speed shortens the mixing cycle by about 3~. Increasing the rotation speed will accelerate heat generation, resulting in a reduction in the viscosity of the rubber compound and a reduction in the mechanical shearing effect, which is not conducive to dispersion.
Mixing temperature
High mixing temperature is conducive to the plastic flow and deformation of raw rubber and rubber compounds, and is conducive to the wetting and mixing of the surface of the solid compound particle particles by the rubber, but it also makes the rubber material The viscosity decreases, which is not conducive to the crushing, dispersion and mixing of the compound particles. Excessively high mixing temperature will also accelerate the thermal oxygen aging of the rubber, causing the physical and mechanical properties of the vulcanized rubber to decline. That is, over-refining will also cause the rubber material to scorch, so effective measures must be taken during the mixing process of the internal mixer. Cooling measures should be taken but the temperature should not be too low, otherwise the rubber material will be crushed and dispersed.
Mixing time
The mixing time required for mixing rubber materials using an internal mixer is much shorter than that of an open mixer under the same conditions. When the mixing quality is required to be constant, the required mixing time shortens as the internal mixer speed and upper ejector pressure increase. Improper feeding sequence and unreasonable mixing operation will prolong the mixing time.
Extending the mixing time can improve the dispersion of the compound in the rubber compound, but it will also reduce production efficiency. If the mixing time is too long, it will easily cause the rubber compound to be over-refined, which will damage the physical and mechanical properties of the vulcanized rubber. It will also cause the thermal history of the rubber compound to increase and scorch will easily occur. Therefore, the mixing time of the rubber compound should be shortened as much as possible. .
Common faults
Leakage control at the joint surface of the internal mixer
During the long-term operation of the internal mixer, due to the influence of vibration, wear, pressure, temperature and repeated disassembly and assembly, the joint surfaces of the internal mixer will leak. The static sealing parts are prone to leakage, which not only causes a large amount of waste of oil products, but also affects the company's on-site management. The traditional method to control internal mixer leakage is to disassemble and open the internal mixer, then replace the sealing gasket or apply sealant, but this is time-consuming and labor-intensive, and it is difficult to ensure the sealing effect, and leakage will occur again during operation. The latest modern repair methods mostly use polymer composite materials, the most mature of which is the Meijiahua technology system. It has superior adhesion, oil resistance and a stretch of 3, and can be disassembled and repaired without affecting the production process. The leakage part can be re-sealed and the economic benefits are significant.