Second vulcanization, also called after vulcanization or two stage vulcanization, refers to rubber products to a certain degree of vulcanization, remove heat source to continue heating vulcanization process.

In a broad sense, rubber products are vulcanized to a certain extent, even if not heated, it can still continue to deepen the vulcanization process under the action of residual heat, or in the storage process of products, or continue to produce crosslinking phenomenon under dynamic action. Of course, it also includes the processing technology of second stage curing by continuing heating; The purpose of secondary vulcanization is to further crosslink rubber products and improve the mechanical properties and compression permanent deformation properties of rubber products. The second vulcanization method is oven hot air vulcanization or hot air vulcanization tank.
At present, many rubber seals or rubber products production units use secondary vulcanization technology to make rubber seal products, technology is also changing with The Times, constantly updated, constantly optimized.

The role of silica gel secondary vulcanization:
When silicone rubber is vulcanized by peroxides, the decomposition of peroxides leads to the reaction of polymers, resulting in low molecular compounds (such as benzene and benzoic acid, etc.) existing in rubber will affect the mechanical properties of rubber. Moreover, silicone rubber in the first stage of heating molding, its crosslinking density is not enough, to make its further vulcanization reaction to increase the density of silicone rubber, tensile strength, resilience, hardness, swelling degree, density, thermal stability than a vulcanization has been greatly improved. If the second vulcanization is not carried out, the performance of the silicone may be affected to a certain extent, and the performance of the product is not better.

The parameters of primary vulcanization and secondary vulcanization may be different, which depends on the actual operation. There are many kinds of silicone vulcanization, high temperature and room temperature. According to the high temperature silicone, for example, is not vulcanized before we usually say raw rubber, rubber mixing is to many additives such as vulcanizing agent, release agent and raw rubber refining together. You can see it from the outside. With the hand a tear will break, no elasticity.

If the good glue is vulcanized at a certain temperature, you can get products, as we usually see: silicone bottle sleeve, silicone bracelet, silicone bottle sleeve, silicone sealing ring, silicone tray, silicone pad, silicone mobile phone cover, etc. As long as it is a regular manufacturer, the use of qualified silicone raw materials to produce silicone products, generally speaking, are non-toxic.