Cyclosiloxanes

Cyclic siloxanes (cyclosiloxanes) are basic members of the broad family of silicone materials.All silicone materials share a common chemistry but each substance is different when it comes to its properties and use.

A common denominator for cyclosiloxanes is that they contain repeating units of silicone (Si) and oxygen (O) atoms in a closed loop, giving it a “cyclic” structure. 

This also gives cyclosiloxanes their unique properties as hybrid inorganic-organic substances. D4, D5 and D6 contain 4, 5 and 6 repeating units respectively. They are three main cyclosiloxanes in commercial production and several decades of research has proven that they are safe for human health and the environment.

Octamethylcyclotetrasiloxane (D4), contains four repeating units of silicone (Si) and oxygen (O) atoms in a closed (cyclic) loop.

Where is it used?

D4 is an odourless, colourless liquid mostly used as an intermediate or basic raw material in the production of silicone rubbers, gels and resins. When used as an intermediate during the manufacturing process, virtually all D4 is consumed with only a tiny amount remaining in final products.

Decamethylcyclopentasiloxane (D5), contains five repeating units of silicon (Si) and oxygen (O) atoms in a closed (cyclic) loop.

Where is it used?

D5 is an odourless, colourless liquid mostly used as an intermediate or basic raw material in the production of silicone rubbers, gels and resins. When used as an intermediate during the manufacturing process, virtually all D5 is consumed with only a tiny amount remaining in final products.

D5 can be added as an ingredient in silicone mixtures used in cosmetic applications such as skin creams and sunscreen, where it may be labelled “cyclomethicone” or “cyclopentasiloxane”. D5 can also be used as a dry-cleaning solvent in closed systems, which significantly limits exposure to workers, consumers and the environment.

Dodecamethylcyclohexasiloxane (D6), contains six repeating units of silicon (Si) and oxygen (O) atoms in a closed loop, giving it a “cyclic” structure.        

Where is it used?

D6 is also an odourless, colourless liquid mostly used as an intermediate or basic raw material in the production silicone rubbers, gels and resins. When used as an intermediate during the manufacturing process, virtually all D6 is consumed with only a tiny amount remaining in final products.

D6 can also be used as an ingredient in silicone mixtures used in cosmetic applications such as skin creams and sunscreen, where it may be labelled “cyclomethicone” or “cyclohexasiloxane”.

Properties

Although D4, D5 and D6 have the same characteristic “Si-O” structure, their properties (including for example the temperatures at which they melt and boil) are very different:

Science

Science

The silicones industry is at the forefront of research and leading the way in ensuring that the different uses of D4, D5 and D6 are valuable and safe.

Uses and Benefits

Uses and Benefits

D4,D5 and D6 are crucial for the creation of a diverse range of silicone materials that provide unique, beneficial characteristics to wide variety of applications and products.