Decamethylcyclopentasiloxane

Decamethylcyclopentasiloxane (CAS 541-02-6) is a cyclic silicone fluid commercially known as cyclomethicone 5, D5, and sold under trade names including Dow Corning 345, VOLASIL 245, and CD3770. It carries EC number 208-764-9 and belongs to the cyclopentasiloxane family of silicone compounds. No E-code designation applies.

In personal care formulations, D5 functions as a volatile carrier that delivers active ingredients to skin or hair and evaporates cleanly without residue, improving spreadability and conditioning. In silicone-based coatings and sealants, it acts as a reactive diluent and crosslinker, reducing viscosity during application while integrating into the cured network.

Decamethylcyclopentasiloxane is supplied as an industrial-grade liquid and is subject to REACH registration requirements within the EU. Procurement teams should note the substance is listed as a Substance of Very High Concern (SVHC) candidate under REACH due to environmental persistence. Standard packaging includes drums and IBCs.