Feeding sequence
Mixer, rubber, carbon black and liquid softener dosing sequence and mixing time is particularly important, is generally the first plus rubber, carbon black, carbon black to mixing in the rubber base dispersed after adding liquid softener, which is beneficial to the mixing, improve mixing effect, shorten mixing the mixing time. The liquid is added early or late adding softener, on mixing disadvantage, caused by uneven dispersion, mixing time, energy consumption increased. The adding time of liquid softener can be determined by the distribution coefficient of K. In addition, the sulfur and the accelerator are usually added at the later stage of the mixing, or they are expected to be added to the press to reduce the risk of coke burning. Small medicine (solid softener, activator, accelerator, antioxidant, anti scorching agent etc.) usually in rubber, carbon black is added before.
Two, top bolt pressure
When mixing the mixer, the rubber material must be subjected to a certain pressure on the top. It is generally believed that the pressure on the top of the 0.3 ~ 0.6Mpa is appropriate. When the rotor speed is constant, further improve the effect of pressure is not large. When the mixing capacity is insufficient, the top pressure can not fully play the role of anchor. The top of the top of the pressure can be reduced to reduce the non filled space in the closed room, filling it up to about 10%. With the increase of capacity and speed, the pressure of the top bolt must be increased. The increase of the top bolt pressure can accelerate the mixing process of raw materials and increase the power consumption during mixing.
Three, rotor structure and type
The geometry and size of the working surface of the rotor largely determine the production capacity and mixing quality of the mixer. The basic configuration of the mixer rotor is of two types: shear rotor and meshing rotor. Generally speaking, the production efficiency of the shear type rotor mixer is high, and it can be quickly fed, quickly mixed and quickly discharged. The utility model has the advantages of high dispersion efficiency, low raw and cooked rate, etc., and is suitable for the manufacture of the hard rubber and the mixing process. The meshing and homogenizing effect of the meshing type rotor mixer is better than that of the shear type rotor, and the mixing time can be shortened by 30-50%.
Four, speed
It is one of the most effective measures to enhance the mixing speed of the mixer. The speed of the mixing cycle is shortened by 30%-50%. Improve the speed will accelerate the heat, resulting in reduced viscosity, mechanical shear effect is reduced, is not conducive to dispersion.
Five, mixing temperature
Mixing high temperature is beneficial to rubber and rubber plastic flow and deformation of rubber is conducive to moist and mixed powder particles to eat on the surface of the solid coordination, but also can make the rubber viscosity decrease, not conducive to coordination and decentralized hybrid particle breaking agent. The mixing temperature will accelerate the thermal oxidative aging of rubber, the mechanical properties of vulcanizate decreased, which is now over the mixing phenomenon; also make rubber scorch phenomenon occurs, so the mixer process must take effective cooling measures; but the temperature is too low, otherwise there will be rubber pressure dispersion.
Six, mixing time
Under the same conditions, the mixing time of the mixer is much shorter than that of the mixer. When the mixing quality is required, the mixing time is shortened with the increase of the mixer speed and the top bolt pressure. Improper feeding sequence, mixing operation unreasonable will extend mixing time. The mixing time can improve the dispersion of the complexing agent in the rubber, but also reduce the production efficiency. The mixing time variable is easy to cause the rubber refining to have the mechanical properties of vulcanizates are damaged, will cause the rubber "hot growth history" and prone to scorch phenomenon, so we should as far as possible to shorten the mixing time of rubber.