The vulcanization process of silicone rubber is not completed in one go, but is divided into two stages of process operation. The rubber material is heated and shaped under pressure (such as mold pressing vulcanization, direct steam vulcanization in vulcanization tanks, etc.) or under normal pressure (such as hot air continuous vulcanization), which is called one-stage vulcanization (or shaped vulcanization); High temperature vulcanization in an oven to further stabilize the physical properties of the vulcanized rubber is called secondary vulcanization (or post vulcanization).

(1) One stage vulcanization
① Model product vulcanization. Plate vulcanization, transfer molding vulcanization, and injection molding vulcanization can be used.
When vulcanizing silicone rubber products, release agents are generally not used. They should be quickly loaded, molded, and pressurized to avoid burning, especially for rubber materials containing vulcanizing agents BP and DCBP. Transfer molding vulcanization is a widely used process for processing silicone rubber compounds. Compared to flat vulcanization with single holes per mold, it has the advantages of short processing cycles and the ability to vulcanize complex rubber parts, especially those with inserts and pins. Compared to injection vulcanization, the equipment cost is lower. Injecting and vulcanizing molded products can improve rest productivity, reduce rest intensity, and also reduce the amount of peroxide used, improve the tear resistance of the product, and improve compression permanent deformation performance. However, the shrinkage rate of the product is relatively high.

② Vulcanization of extruded products. Steam pressure vulcanization, hot air continuous vulcanization, liquid vulcanization tank continuous vulcanization, drum vulcanization, and radiation vulcanization can be used. The first three methods are more commonly used.

(2) Two-stage vulcanization
After a period of vulcanization, some low molecular weight substances exist in the silicone rubber product, which affects its performance. For example, when using a universal vulcanizing agent (such as vulcanizing agent BP or DCBP) for rubber, after a period of vulcanization, the quality of the acidic substance decomposed by the vulcanizing agent will increase the porosity of sponge pores and reduce density; Increasing the amount of vulcanizing agent will reduce the porosity of sponge pores, increase density, and result in thicker pore walls. In addition, the vulcanization temperature also has a significant impact on the pore formation of sponges.