Secondary vulcanization is also called post-vulcanization or two-stage vulcanization. It refers to a process in which rubber products reach a certain degree of vulcanization, and heat vulcanization is continued after removing the heat source.

Broadly speaking, rubber products are vulcanized to a certain degree. Even if they are not heated, they can continue to deepen the vulcanization process under the action of waste heat, or during the storage of the product, or continue to crosslink under dynamic action. Of course, it also includes the process of continuous heating for two-stage vulcanization; the purpose of secondary vulcanization is to further crosslink rubber products, improve the mechanical properties and compression set properties of rubber products, etc .; the method of secondary vulcanization is oven hot air vulcanization or vulcanization Hot air secondary vulcanization of tanks; At present, many rubber seals or rubber products production units use secondary vulcanization technology to make rubber seal products, and the technology is constantly updated and optimized with the changes of the times!

The role of secondary vulcanization of silicone rubber: When silicone rubber is vulcanized with peroxide, after the decomposition of peroxide initiates a polymer reaction, low molecular compounds (such as benzene and benzoic acid) are generated in the rubber and will affect the mechanical properties of the rubber. Moreover, after the silicone rubber is heated and molded in the first stage, its crosslinking density is not enough. It needs to be further vulcanized to increase the density of the silicone rubber. The tensile strength, resilience, hardness, swelling degree, density, and thermal stability are all better than one. There is a big improvement in vulcanization. If the secondary vulcanization is not carried out, the performance of the silica gel produced may be affected to some extent, and products with better performance may not be obtained. The parameters of the primary vulcanization and the secondary vulcanization may be different, which is different from the actual Operation is related! There are many types of silicone vulcanization, including high temperature and room temperature. Take high-temperature silicone as an example. Before vulcanization, it is what we usually call raw rubber. Mixing rubber is made by mixing many additives such as vulcanizing agent and mold release agent with raw rubber. It can be seen from the appearance. When you pull it with your hand, it breaks without elasticity. If the compounded rubber is vulcanized and molded at a certain temperature at a certain temperature, you can get products, just like what we usually see: silicone bottle covers, silicone bracelets, silicone milk bottle covers, silicone seal rings, silicone trays , Silicone pads, silicone cell phone sets, etc., as long as they are regular manufacturers, using qualified silicone raw materials, the production of silicone products is generally non-toxic.