Raw silicone rubber is the base material for manufacturing rubber products, and generally refers to the unvulcanized rubber compound. Add 0.05-0.1% ammonia water to the near neutral liquid flowing out of the rubber tree to prepare latex. Latex needs to be processed into dry rubber, which is commonly referred to as natural raw rubber.

       The quality of raw silicone rubber is affected by the following three factors:

       1. The influence of trifunctional bond content on the quality of raw silicone rubber. There are two sources of trifunctional bond in the raw silicone rubber: one is the poor quality VMC brought by the raw material base cyclosiloxane mixture (DMC) or methyl vinyl cyclosiloxane mixture (VMC) Contains quite a lot of trifunctional chain links; the second is produced during the polymerization process. Compared with normal silicone rubber, it is more difficult to disperse white carbon black in raw rubber with more trifunctional chain links, so it takes longer time to eat powder during mixing; and the uniformity of white carbon black dispersion Inferior, so the performance of the vulcanizate is poor, the strength is low, and it is not transparent.

       2. The influence of trimethylamine content on the quality of raw silicone rubber. The decomposition of tetramethylhydroammonium amine generates trimethylamine. Although the mass of trimethylamine is only 65% ​​of the catalyst mass and the boiling point is 2.9℃, most of it has been removed after the process of removing low molecular weight from the raw rubber; however, a small amount of trimethylamine still remains in the raw rubber. The rubber compound needs both high temperature and peroxide during the vulcanization process, so trimethylamine is easily oxidized into nitro and nitroso groups, and further oxidized into compounds containing chromophores, making the vulcanized rubber appear yellow . Appropriately reducing the amount of catalyst and increasing the temperature of the demolition device can reduce the residual amount of trimethylamine below the sensitivity of the detection instrument, and the effect of yellowing can be completely eliminated.

       3. The impact of molar mass release on the quality of raw silicone rubber. Raw rubber with a broad molar mass release has more molecules with a degree of polymerization of 10-400. On average, some of these molecules have only one crosslinking point, and some even have no crosslinking point. Therefore, they have no contribution to the strength of the vulcanizate. The mechanical properties of the vulcanizate will be slightly worse. When the temperature of the polymer is too low or When the material is discharged before the polymerization balance is reached, there will be more low molar mass parts in the raw rubber; just like the addition of silicone oil plasticizer to the raw silicone rubber, it will cause the raw rubber to become sticky and reduce the strength of the vulcanized rubber. . In order to prevent the raw rubber from being discharged when the polymerization balance is not reached, when the large foreign companies produce raw rubber, the agitation of the batch polymerization reactor is always on. In this kind of polymerizer, whether it is near-wall materials or near-center materials, the polymerization conditions are very uniform; however, the equipment investment of this kind of polymerizer is large, the energy consumption is too high, and the power cost is also high.