Structured mixed rubber is a mixture of hydrophilic silica and raw rubber that gradually hardens, decreases plasticity, and loses the process performance of tempering molding during storage. The main reason for the formation of structural rubber compounds is that the silicon hydroxyl group on the surface of silica interacts with the silicon oxygen bond in the raw rubber molecule or the terminal hydroxyl group in the raw rubber molecule to produce hydrogen bonds, or even chemical bonding, which changes the linear polysiloxane into the solid structure of the pseudo crosslinked semi elastomer, reduces the solubility of rubber compounds, and increases the gel content.

Generally speaking, the plasticity of compounds can be restored through backmixing, and the length of backmixing time depends on the severity of the compound's structure. In order to reduce the hydrogen bonding and structural degree of the compound, structural control agents such as hydroxysilicone oil or alkoxysilane can be added, and an appropriate amount of dimethyl silicone oil can be added to regulate the flow performance of the compound. Adding too much hydroxysilicone oil to the rubber material can lead to a sticky feel and slow vulcanization speed. Therefore, it is necessary to find a suitable balance point to control each type of rubber material within a suitable range of plasticity values. Low or high plasticity can have an impact on the later processing of products. If the plasticity is low, the rollers may stick during the processing, and there may be mucous membranes during the product production process. If the plasticity value is too high, it will lead to poor structural and flowability of the rubber material, and the product may lack glue or flow marks.

It can also be improved from the production process of mixed rubber. We are currently using a one-step method for mixed rubber production, which results in incomplete bonding between white carbon black and raw rubber. Although there are no obvious abnormalities on the surface, small white spots can sometimes be observed in the rubber material, which can be produced through the process of mixing (at room temperature) - vulcanization - internal mixing, thereby improving the bonding degree between white carbon black and raw rubber and improving the structure of the mixed rubber.

Addition-curing HTV silicone rubber, plz check MY D0170