Cause: Due to the high permeability of silicone rubber, especially the mixed rubber made of silica by precipitation method, with the increase of relative humidity in the air, the water content of the mixed rubber also increases linearly. 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 of the rubber surface is very slow or cannot be released at all, resulting in bubbles on the surface of the extruded products. General precipitation silica is not suitable as silicone rubber filler for extrusion molding because of its high water content.

Solution: can use alkoxy silane white carbon black surface treatment, so that it has hydrophilic surface into hydrophobic surface, reduce the water absorption rate of rubber; It can also reduce the water absorption of the rubber material through high temperature treatment, so as to improve the bubble of the extruded rubber material.

Currently extrusion plastic material in production, pay attention to safety, technology can be used in a gas phase method on mixing rubber as a first step, rubber after cold steel out, placing it in 30 ~ 40 ℃ keeping in good health health preservation processing eight hours, again for rubber vacuum heat treatment, strict control of rubber effective mixer mixer temperature and time, namely rubber mixer time and temperature in the high temperature period, In order to improve the extrusion of rubber bubble problem