Methyl silicone oil is one of the earliest, most widely used and most commonly used organosilicon polymers. There are two main production methods of methyl silicone oil: acid balance method and alkali balance method. Acid balance method is suitable for the production of low viscosity silicone oil with viscosity below 500mm2 / S. in general, concentrated sulfuric acid is used as catalyst to react at 50 ~ 60 ℃, then acid is removed by water washing, low boiling matter is removed, activated carbon is added for decolorization, and transition to finished product. While alkali balance method is suitable for the production of medium and high viscosity silicone oil with viscosity above 100mm2 / s. In the production of methyl silicone oil, the components in DMC (dimethyl mixed ring) will reach the optimal activation state at different temperatures, and the ring opening polymerization will be carried out respectively, which improves the conversion rate and greatly improves the production efficiency.
After ring opening polymerization, catalyst (CH3) 4noh is difficult to be fully decomposed in the process of catalyst breaking, and a small amount of ammonia gas after decomposition is also miscible in the system, resulting in peculiar smell of silicone oil. The method of cooling the system to below 140 ℃ and bubbling with dry air is adopted to increase the gas pressure of the system, so as to achieve the purpose of discharging the pungent smell.
When the temperature is controlled between 90 ℃ and 120 ℃, and the temperature is reduced to 140 ℃ after desalting and the air is bubbled, colorless, odorless and qualified methyl silicone oil can be obtained. The average conversion rate is increased from 65% to more than 80%.
(source: silicon material)