Silicone rubber is the largest category of silicone products, which is a kind of polymer materials with both inorganic and organic properties with Si-O-Si bond inorganic structure in the main chain and organic groups in the side chain. Silicone rubber is divided into: high temperature vulcanized silica gel and room temperature vulcanization. High temperature vulcanized silicone rubber usually needs two-stage vulcanization to eliminate the decomposition residue in the oxide, which is the further crosslinking of silicone rubber to achieve the best physical properties. The second stage vulcanization makes the silicone rubber yellow and the transparency decreases, which directly affects the appearance of the product. The application scope is limited to food, medical treatment, solar photovoltaic and other industries.

1. Adding special modified silicone oil can effectively inhibit the yellowing of silicone rubber after secondary vulcanization, and accelerate the vulcanization speed and crosslinking density of silicone rubber;

2. Add a paste like double 2,5 vulcanizing agent with high amount of hydrogen silicone oil to significantly improve the anti yellowing effect of silicone rubber, improve the transparency of silicone rubber and prevent the splashing of vulcanizing agent;

3. Adding organic surfactant into silica to control the size of secondary particles, and effectively control the yellowing degree of silicone rubber under the action of composite anti yellowing agent;

4. Add an anti yellowing agent called pyrophosphoric acid to enhance the anti yellowing ability of the compound without reducing the physical and mechanical properties of the compound.

Silicone rubber has heat resistance, weather resistance, electrical insulation, chemical stability and physiological inertia. It is mainly used in the field of electrical and electronic industry and plays an important role in all industrial fields such as office equipment, automobile, food, household products and leisure products. The yellowing caused by the two-stage vulcanization of silicone rubber has a great adverse impact on the product appearance, thus greatly reducing the application range of silicone rubber. It is of great significance for how to avoid yellowing of silicone rubber products in the process of production and application, especially for the expansion of its application field.