The influence of the filling amount of silica on the physical properties of rubber is very important. Generally, as the filling amount increases, the tensile strength, tear strength, tensile strength, hardness, specific gravity, etc. of the vulcanized rubber are all increased. It is significantly improved and the amount of wear is reduced. Different rubber varieties should achieve the best reinforcing performance and wear resistance. The optimal filling amount for white carbon black is different. For the crystalline NR, the optimum amount of CR is lower, generally 40-50 parts, but The optimum reinforcing filling for synthetic rubber is generally between 50 and 70 parts.
As the amount of silica increases, the physical properties are gradually increased, but the optimum amount of silica is a range. If the dosage exceeds the range, it can only be used as a filler. Because the filling amount is too large, it is equivalent to reducing the amount of glue in the formula, and can only be used as a compatibilizer, and the physical properties are decreased. Due to the high structure between the white carbon black and the large specific surface area, the larger the filling amount, the more difficult it is to mix evenly into the rubber. Generally, in the high-filled white carbon black formula, the softening oil must be filled at the same time to reduce the rubber. The viscosity of the material reduces the force between the silica to be evenly distributed in the compound; this is widely used in many low-grade, high-transparent beef tendons, with a maximum filling capacity of 150 parts.