Silane coupling agent Si-75 is a double functional polysulfide organosilane coupling agent, which can significantly improve the physical and mechanical properties of rubber products such as tensile, tear resistance and wear resistance. It is suitable for vulcanized rubber system with white carbon black or silicate as reinforcing agent, which can improve the reinforcing ability of filler. This product has a low - active second - rate functional group, so it can provide reliable char safety.