The vulcanization process of high-temperature silicone rubber is generally divided into two stages, namely one-stage vulcanization and two-stage vulcanization.
One-stage vulcanization, also known as setting vulcanization, has its vulcanization method, temperature and time determined by the molding process adopted, the type of rubber compound and the thickness of the vulcanized product. Molded products are generally formed on a flat vulcanizing machine, with vulcanization temperatures and times of 150 to 180 degrees Celsius and 10 to 30 minutes respectively. Silicone rubber preforms that have undergone extrusion, calendering, gluing and compounding can be vulcanized using vulcanizing channels or vulcanizing tanks, with steam and hot air heating for vulcanization, that is, molding and crosslinking are carried out separately.
Secondary vulcanization, also known as post-vulcanization, aims to remove volatile or harmful volatile substances remaining in the product, improve cross-linking, and stabilize the physical and mechanical properties of the vulcanized rubber. Silicone rubber products after two-stage vulcanization have excellent compression set, dielectric properties and stable physical and mechanical properties. The second-stage vulcanization is carried out in a forced convection high-temperature constant temperature box at a temperature of 180 to 200℃ for 2 to 8 hours.
Silicone rubber compound can be made into various molded products (such as various rubber sheets, gaskets, washers, etc.), extruded products (such as various rubber hoses, rubber ropes, rubber strips, wire sheaths, etc.), and rubber cloth products (such as self-adhesive cloth, isolation cloth, etc.) by using different molding methods.