Silicone Oil 1.5 cSt (Dimethicone, PDMS)

Silicone Oil 1.5 cSt is the lightest pourable grade on the linear PDMS (dimethicone) ladder — the first free-flowing fluid above the volatile silicones, sitting just over 1.0 cSt octamethyltrisiloxane and 0.65 cSt hexamethyldisiloxane and well below the 5 cSt workhorse. It carries the lowest surface tension and the fastest wet-out of the liquid dimethicones, flashes to a thin film almost on contact, and dries down to a light, non-greasy slip. That combination makes it a fast-spreading carrier and diluent, an anti-spatter and release aid, a thin dielectric and heat-transfer fluid, an antifoam base oil, and a co-fluid in personal-care formulation. Part of the grade is volatile, so it is more flammable than the heavier fluids — handling, flash point and volatility data are on the current SDS.

Typical Properties

The values below describe the nominal 1.5 cSt grade. They are typical values, not a specification; the Certificate of Analysis (CoA) for the lot you purchase governs.

Applications

In personal-care formulation, 1.5 cSt is a fast-spreading carrier and emollient fluid that wets out on contact and dries to a light, non-greasy, non-cooling slip. Formulators increasingly reach for low-viscosity linear dimethicones as alternatives to the volatile cyclic siloxanes (cyclomethicones such as D5), which face tightening restrictions in several markets; the linear fluid gives a comparable dry, weightless feel and acts as a carrier or co-solvent for actives, sunscreen filters, antiperspirant and deodorant systems, hair serums and color cosmetics. This describes formulation behavior — spreadability and feel — and makes no skin-health claim. As a low-temperature dielectric and heat-transfer fluid, 1.5 cSt brings high dielectric strength, an ultra-low pour point and a low viscosity-to-temperature coefficient, so it stays mobile and pumpable far below freezing; it is a common laboratory-bath and freeze-drying heat-transfer medium and a thin electronics-cooling fluid. As an anti-spatter and release aid, the thin film migrates into tight geometry and demolds cleanly. Reapply more often than with a 10 cSt film, because the deposit is lighter. As an antifoam base oil, it is the continuous phase that carries hydrophobic silica into aqueous and non-aqueous systems; dose against your foam load, not to a fixed percentage. It also works as a spreading carrier and diluent in polishes and spray lubricants, thinning heavier silicones and resins without raising surface tension. The trade-off runs through all of these: the lighter the grade, the faster it spreads and the less it persists, and part of a 1.5 cSt charge is volatile, so it is the wrong pick where a fluid has to stay put. Confirm the grade against the durability and volatility your application needs.

Where 1.5 cSt sits on the ladder

The dimethicone fluid ladder runs from volatile to viscous. The 1.5 cSt grade is a discrete volatile siloxane — decamethyltetrasiloxane (MD2M), CAS 141-62-8 — rather than the polymeric PDMS (CAS 141-62-8) used from roughly 5 cSt upward. Below 1.5 cSt are the volatile grades (1.0 cSt octamethyltrisiloxane and 0.65 cSt hexamethyldisiloxane), which evaporate cleanly and leave little residue. Above it sit 5 cSt and 10 cSt, which keep some of the fast spreading but are less volatile and lay down a more persistent film. 1.5 cSt is the bridge: lighter and faster than 5 cSt, heavier and more substantive than the pure volatiles. If you need the deposit to last, step up to 5 or 10 cSt; if you need it to flash off entirely, step down to the volatiles. The silicone oil viscosity guide walks the full ladder grade by grade.

Grades & bulk sourcing

RawSource supplies Silicone Oil 1.5 cSt in drums, totes and IBCs, with domestic US sourcing; request a bulk quote for current availability and lead time. Every lot ships with a CoA, and the SDS is available on request. Confirm the grade for your application before you commit a production run — match viscosity to the spreading, persistence and volatility your formulation needs.

Related products

Compare neighboring grades and identifiers: Silicone Oil 2 cSt, Silicone Oil 5 cSt, Silicone Oil 10 cSt, Octamethyltrisiloxane (1.0 cSt), Hexamethyldisiloxane (0.65 cSt), and the parent Dimethicone (PDMS fluid).