Explanation

Under certain conditions of time, temperature and pressure, the long chain molecules of rubber produce crosslinking, and the linear structure transformation into three-dimensional network structure. After vulcanization, the plastic flow of rubber decreases in a wide range of temperatures, the constant tensile stress, tensile strength, hardness and elasticity increase, and the swelling resistance improves. Therefore, only after vulcanization can rubber become a valuable materials. vulcanization methods can be divided into chemical vulcanization and physical vulcanization according to whether vulcanizing agent is added. The most commonly used method for rubber molding is chemical vulcanization with vulcanization additives (such as sulfur and other vulcanizing agent, vulcanization accelerator, vulcanization activators, etc.); Physical vulcanization, such as radiation vulcanization, is to cause the molecular chain of crude rubber to produce crosslinking bonds to form a network structure under the action of high-energy radiation. According to the temperature conditions of vulcanization, it can be divided into cold vulcanization, room temperature vulcanization and hot vulcanization. Among them, thermal vulcanization is the most important vulcanization method. Hot vulcanization can be divided into direct vulcanization, indirect vulcanization and gas mixed vulcanization according to vulcanization medium and heating mode. According to vulcanization operation mode, there are intermittent vulcanization and continuous vulcanization, the latter is applicable to rubber products with unlimited length. According to the common vulcanization equipment, it can be divided into vulcanization tank, flat vulcanization machine, individual vulcanization machine, injection pressure vulcanization machine and hot bake vulcanization machine.

Classification