How to improve the structuring of existing rubber compounds?

The structuring of the rubber compound is due to the mixing of the hydrophilic white carbon black and the raw rubber, which gradually hardens during the storage process, reduces the plasticity, and gradually loses the process performance of the refining and molding process, resulting in structuring. The main reason is that the silicon hydroxy group on the surface of silica and the silicon-oxygen bond in the raw rubber molecule or the terminal hydroxyl group in the raw rubber molecule to form hydrogen bonds, or even chemically, to convert the linear polysiloxane into a pseudo-crosslinking. The semi-elastomer solid structure reduces the solubility of the rubber compound and increases the gel content.

Generally speaking, the rubber can be restored to plasticity by refining, and the length of refining time depends on the structural severity of the rubber compound. In order to reduce the hydrogen bonding of the rubber compound and reduce the structural degree of the rubber compound, a structural control agent such as hydroxy silicone oil, diphenyl silicon glycol or alkoxysilane may be added, and an appropriate amount of dimethicone may also be added. Adjusting the flow properties of the compound, adding too much hydroxy silicone oil to the compound will result in a sticky feel and a slow vulcanization rate. This is to find a suitable balance point, and each type of compound can be controlled in one. Appropriate range of plasticity values, low or high plasticity values will affect the processing of later products, the plasticity value is low, there will be sticking rolls during processing, and mucous membranes or rotting may occur during the production process of the products. Phenomenon; high plasticity value will cause structural sizing of the rubber compound and poor fluidity of the rubber compound, and the product may be lacking in glue or flow marks.

It can also be improved from the process of rubber compound production. Now we use the one-step method for the production of rubber compound, so that the white carbon black and the raw rubber are not completely integrated in the process, although it can not be found on the surface. Obvious abnormal situation, but sometimes it is observed that there are small white spots in the rubber compound, which can be produced by mixing (normal temperature)-health-mixing process, improving the bonding degree of white carbon black and raw rubber to improve the glue. Structured phenomenon.

Another selection of raw rubber, the molecular weight of the raw rubber is too high and too low, there are terminal hydroxyl groups or other impurities in the raw rubber molecules, resulting in the molecular weight of the raw rubber, will affect the processing properties and vulcanization properties of the rubber compound, Therefore, in the raw material control, it is best not to have a peak in front of D3. The same molecular weight heading agent should be added as much as possible. If possible, calculate the conversion rate of each batch of rubber in the production process, and the raw rubber will be raw. Good quality control.