Silicone Knowlege: How is Silicone Produced?

Mar 23, 2023JE SILICONE

Silicon, the main chemical element used to make silicones, does not exist in a pure form naturally, and is therefore extracted from silicates (or silica) embedded in sand or rocks. The full silicate-to-silicone value chain includes the extraction of silicon to obtain silicon metal, which is then transformed to obtain silicone intermediates, obtained by mixing grounded silicon with methyl chloride and transformed through different stages of synthesis into chlorosilanes and then siloxanes.

Let’s explore the various steps involved in silicone production.

Step 1: Isolate Silicon From Silica
Isolating silicon from silica is the first step in producing silicone. To achieve this, a large volume of quartz sand is heated to temperatures as high as 1800 degrees Celsius. Pure, isolated silicon is the result. Once it cools, manufacturers can grind it into fine powder.

Step 2: Combine Powder With Methyl Chloride
The fine silicon powder is mixed with methyl chloride. Applying heat again activates a reaction between the components forming what is known as methyl chlorosilane. Methyl chlorosilane is a mix containing several compounds, the most predominant of which, dimethyldichlorosilane, is the primary building block of silicone.

Step 3: Distill the Mixture
Getting from dimethyldichlorosilane to silicone requires a complex distillation process to separate the various components of methyl chlorosilane from one another. Because chlorosilanes have different boiling points, this step involves heating the mixture to a series of precise temperatures.

Step 4: Addition of Water
Following distillation, combining water with dimethyldichlorosilane causes a separation of hydrochloric acid and disilanol.

The hydrochloric acid then acts as a catalyst for the disilanol, causing it to condense into polydimethylsiloxane.

Step 5: Polymerization of the Silicone
You’ll notice polydimethylsiloxane has a siloxane bond. This bond is the silicone’s backbone. Polymerizing silicone involves several different methods depending on the finished product’s desired properties.

While the silicone production process may seem complex, in reality, it’s fairly straightforward and can take place on a mass scale for a relatively low cost. As such, it’s little wonder that versatile silicone has emerged as one of the most popular elastomers for commercial and industrial use.