1, mixing:
      When mixing with an open mill, it is best to equip the opener roller with a dust or air blower to reduce the flying of the silica. During the mixing process, no other impurities or colloidal particles should be mixed in. The temperature should be controlled below 40 °C, and the cooling water should be opened. The mixing and mixing of the open mill is slow, and the mixing time of each batch of rubber is about 20-40 min. Mixing with an internal mixer not only improves production efficiency, reduces labor intensity, but also reduces the flying of silica and improves the operating environment.
      The sequence of mixer mixing operations is basically similar to that of an open mill, but the interval time requirements are not critical. The mixing time of each batch of rubber is about 8 to 18 minutes, and the filling factor of the internal mixer should be controlled within the range of 0.7 to 0.75. The discharge temperature is related to the type of filler and should generally be controlled in the range of 50 ° C to 70 ° C.
2, heat treatment:
      When a fumed silica which has not been surface-modified is used as a reinforcing agent, a structure controlling agent must be added to the compound. Therefore, the heat treatment of the rubber compound becomes a necessary process. The purpose of the heat treatment is mainly to further combine the structure control agent with the surface of the silica (Si-OH) and eliminate the low molecular volatiles in the rubber. The general heat treatment conditions are: treatment at 160 ° C to 200 ° C for 1 to 1.5 h under nitrogen protection or a reduced pressure kneader.
3. Filtering:
      For extruded products, calendered products, rubberized products, and film products, mechanical impurities and undispersed compound particles are one of the main factors leading to quality problems in products. Therefore, the compound used for the above products must be filtered. Filters can be used in the filter, or can be replaced by ordinary extruders. The temperature of the barrel and screw should be controlled to a minimum, and the filter size should be 120-200 mesh.
4, refining:
      After the rubber is parked, the gel content increases and the plasticity decreases, so it is necessary to carry out the refining during use. The rubber material refining should be suitable, the refining is insufficient, the rubber material has poor softness and the surface is not smooth; and if the refining is excessive, the rubber material surface will be sticky, which is not conducive to operation.