Secondary vulcanization is from the machine molded products, and then the production of the product in the oven for a period of time (180 degrees to 200 degrees, generally for two or three hours), known as the second vulcanization. Secondary vulcanization is also called post-vulcanization. Commonly used for silicone rubber, fluorine rubber and fluorine silicone rubber vulcanization.

The role of secondary vulcanization: silicone rubber vulcanization by peroxide, peroxide decomposition caused by the polymer reaction, the generation of low molecular compounds (such as benzene and benzoic acid, etc.) in the rubber will affect the mechanical properties of rubber. Moreover, the crosslinking density of silicone rubber is not enough after heating and forming in the first stage. Only by further vulcanization reaction can the density of silicone rubber be increased. Tensile strength, resilience, hardness, swelling degree, density and thermal stability are better than those of single curing. If the secondary vulcanization is not carried out, the performance of silica gel may be affected to a certain extent and the performance of better products can not be obtained.