Cause: Due to the greater permeability of silicone rubber, especially the precipitation of silica compound, with the increase of relative humidity in the air, the water content of the compound also linearly increased. When the water is too much, the silicone rubber changes from transparent to opaque, especially in winter because of the low ambient temperature, the water release time on the surface of the rubber material is slow or cannot be released at all, resulting in the surface of the extruded products easy to bubble. General precipitation silica, due to its own water content is too high is not suitable for extrusion of silicone rubber filler.

Solution: Alkoxy silane can be used to treat the surface of white carbon black, so that it has a hydrophilic surface into hydrophobic surface, reduce the water absorption of rubber; It can also reduce the water absorption rate of the compound by high temperature treatment, so as to improve the bubble problem of the extruded compound.

At present, in the production of extruded compound, in the existing formula system, the 2# structure control agent can be replaced with dieoxysilane to better deal with the water on the surface of white carbon black. Of course, attention should be paid to the safety in the production process. The first step of the process can be used in the gas phase mixing rubber. It is placed in 30~40℃ regimen room for regimen treatment for about 8 hours, and then vacuum heat treatment of the compound, strictly control the effective mixing time and mixing temperature of the compound, that is, the mixing time and temperature of the compound in the high temperature section, so as to improve the bubble problem of the extruding compound.