Decamethylcyclopentasiloxane(CSA#541-02-6)
Key Physical & Chemical Properties
Chemical Formula: C₁₀H₃₀O₅Si₅
Molecular Weight: 370.77
Boiling Point: Approximately 210°C
Density: About 0.958 g/cm³ (at 25°C)
Appearance: Colorless, transparent, with little or no odor
Solubility: Insoluble in water; readily soluble in organic solvents like ethanol and ether
Main Applications
1.
Cosmetics & Personal Care Products
As a key volatile silicone oil, it is widely used in:
Skincare (e.g., moisturizers, serums, sunscreens): Enhances spreadability and reduces greasiness
Makeup (e.g., foundations, primers): Promotes even application and improves wear resistance
Hair Care (e.g., shampoos, conditioners): Adds smoothness and improves combability
Deodorants & Perfumes: Acts as a solvent and carrier, facilitating the release of active ingredients
2.
Industrial Applications
Used as an intermediate in the synthesis of silicone rubber and resins
Serves as a cleaning agent or lubricant for precision instruments
Applied in electronics and automotive manufacturing for specialized material processing
Safety & Regulatory Updates
While D5 itself has low acute toxicity and is assessed by the EU’s SCCS as posing minimal health risk under current usage conditions, it may contain trace amounts of D4 (tetramethylcyclotetrasiloxane), which is classified by the EU as a reprotoxic substance. Therefore, regulatory focus centers on controlling D4 impurity levels.
Key regulatory trends include:
EU REACH Regulation: Since 2020, limits D5 concentration to ≥0.1% in rinse-off cosmetics; bans use in leave-on cosmetics starting June 6, 2027
Canadian Government: Lists D5 as a reportable substance of potential environmental concern, but considers risks to biodiversity manageable under normal use
China and other regions: No full ban yet, but manufacturers are encouraged to improve purity and reduce environmental accumulation risks
High-purity (≥99%) D5 is supplied by several specialty chemical companies, including Jiangsu Reign, Tosoh, and Linkshine, catering to high-end formulation needs.
