1. Cooperate with
Hot vulcanized silicone rubber compound mainly includes reinforcing agent, vulcanizing agent and some special additives, generally only need to have 5 ~ 6 components can constitute the practical formula.


2. Formulation design should consider the following points:

(1) silicone rubber for high saturation of raw rubber, usually can not use sulfur vulcanization, should use organic peroxide as vulcanizing agent, so the rubber material shall not contain active substances that can and peroxide decomposition products (such as tank method carbon black, some organic accelerator and anti-aging agent, etc.), otherwise it will affect the vulcanization.

(2) silicone rubber products are generally used at high temperature, the compound should be kept stable at high temperature, usually choose inorganic oxide as reinforcing agent.

(3) Silicone rubber in trace acid or alkali and other chemical reagents under the action of easy to cause the cracking and rearrangement of siloxane bonds, resulting in the reduction of silicone rubber heat resistance. Therefore, it is necessary to consider the acidity and alkalinity of the peroxide decomposition products when selecting the complexing agent, so as not to affect the properties of the vulcanized rubber.


4 curing agent and curing mechanism

(1) curing agent
The curing agents used for thermally vulcanized silicone rubber mainly include organic peroxides, aliphatic azo compounds, inorganic compounds and high-energy rays, among which organic peroxides are the most commonly used. This is because organic peroxides are generally stable at room temperature, but they can quickly decompose to produce free radicals at higher vulcanization temperatures, resulting in cross-linking of silicone rubber.
These peroxides can be divided into two categories according to their activity: one is universal, high activity, all kinds of silicone rubber can vulcanize; The other is vinyl special type, because of its low activity, can only contain vinyl silicone rubber vulcanization.

(2) mechanism of vulcanization
When silicone rubber is vulcanized by peroxides, the crosslinking of peroxides to silicone rubber is carried out by free radical reaction between two activated methyl or vinyl groups.
Silicone rubber can also be vulcanized by radiation with high energy rays in addition to the above mentioned peroxides. Radiative vulcanization is also carried out by the free radical mechanism, when the raw rubber in the vinyl mole fraction is higher (0.01) or with other rubber, can also be vulcanized with sulfur yellow, but the performance is very poor.