What are Cyclosiloxanes?
Cyclosiloxanes are basic members of the broad family of silicone materials. All silicone materials share a common chemistry but each substance is different with regard to its properties and use. D4, D5 and D6 are the three cyclosiloxanes in commercial production and their use has been proven safe for human health and the environment.
On this website you'll learn more about their properties, where they are used and why they are safe.
Visit the 'What's New' section for studies and useful links related to cyclosiloxanes or check out the Frequently Asked Questions on D4 and D5.
D4
Octamethylcyclotetrasiloxane, more commonly known as D4, contains four repeating units of silicone (Si) and oxygen (O) atoms in a closed loop, giving it a "cyclic" structure.
Where is it used?
D4 is an odorless, colorless 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.
D4 can also have a minor use as an ingredient in silicone mixtures used in cosmetic applications such as skin creams and deodorants, where it may be labelled "cyclomethicone" or "cyclotetrasiloxane".
For more information about D4 in relation to health and the environment please visit the D4 section on this website.
To learn more about the many applications of silicones, visit CES - Silicones Europe or the Silicones Environmental, Health and Safety Center or the Silicone Industry Association of Japan.
Find out more about the safety profiles and the environmental properties of D4
D5
Decamethylcyclopentasiloxane, more commonly known as D5, contains five repeating units of silicon (Si) and oxygen (O) atoms in a closed loop, giving it a "cyclic" structure.
Where is it used?
D5 is an odorless, colorless 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 deodorants, 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.
How does it work?
In dry cleaning, D5 acts as a solvent and is an alternative to perchlorethylene. It carries the detergent to the clothes and rinses away suspended oils and dirt but it does not interact with textiles and, therefore, helps maintain the quality and color of clothes that are dry cleaned.
For more information about D5 in relation to health and environment please visit the D5 section on this website.
To learn more about the many applications of silicones, visit CES - Silicones Europe or the Silicones Environmental, Health and Safety Center or the Silicone Industry Association of Japan.
Find out more about the safety profiles and environmental properties of D5
D6
Dodecamethylcyclohexasiloxane, more commonly known as 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 an odorless, colorless 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 deodorants, where it may be labelled "cyclomethicone" or "cyclohexasiloxane".
How does it work?
In personal care products, cyclosiloxanes act as “carriers”, allowing products to spread smoothly and easily and providing a silky feel during application.
For more information about D6 in relation to health and environment please visit the D6 section on this website.
To learn more about the many applications of silicones, visit CES - Silicones Europe or the Silicones Environmental, Health and Safety Center or the Silicone Industry Association of Japan.
Find out more about the safety profiles and environmental properties of D6