Mineral Fillers & Pigments Available — Bulk Only

Silica Dimethyl Silylate (Hydrophobic Fumed Silica)

CAS 68611-44-9

Fumed silica capped with dimethylsilyl groups so it thickens oils and stays free-flowing in moisture. It is used as a rheology modifier and anti-settling thickener for non-aqueous and oil-rich systems, as an anti-caking and flow aid, and as an absorbent and bulking agent.

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HS Code
2811.22
At a Glance
Material Family
Mineral Fillers & Pigments
Record Type
UVCB
Primary Role
Defoaming / Foam Control · Viscosity Modification
Functional Roles
SILICA DIMETHYL SILYLATE
ANTICAKINGANTIFOAMINGEMULSION STABILISINGSKIN CONDITIONING - EMOLLIENTVISCOSITY CONTROLLING
Applications & Use Cases
  • Rheology/thixotropy: Thickens oils and anhydrous bases and controls sag.
  • Anti-settling: Suspends pigments and fillers in non-aqueous systems.
  • Anti-caking/flow aid: Keeps powders free-flowing and moisture-resistant.
  • Absorbent/soft-focus: Oil absorption and bulking in cosmetics.
Physical Properties
appearance
white fluffy powder (typical)
primary_particle_size
~16 nm (typical)
bet_surface_area
90-130 m2/g (typical, grade-dependent)
carbon_content
0.6-1.2 wt% (typical)
tapped_density
~50 g/L (typical)
ph_4pct_dispersion
3.6-4.5 (typical, in 1:1 water/methanol)
loss_on_drying
<=0.5 wt% (2 h, 105 C, typical)
sio2_content_ignited
>=99.8 wt% (typical)
wettability
hydrophobic (not wetted by water)
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2811 . 22
Chapter 28
Inorganic chemicals; compounds of precious metals and rare-earth metals
Heading 28.11
Internationally harmonized (WCO HS)
Subheading 2811.22
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
68611-44-9
INCI Name
SILICA DIMETHYL SILYLATE
Synonyms & Trade Names
Hydrophobic fumed silica Dimethyldichlorosilane-treated fumed silica Silica dimethyl silylate (INCI) DDS-treated silica Hydrophobic synthetic amorphous silica Comparable to Aerosil R972
Full Description

Silica Dimethyl Silylate (CAS 68611-44-9) is a synthetic amorphous fumed silica surface-treated with dimethylsilyl groups to render it hydrophobic. It is used as a rheology modifier and anti-settling thickener for non-aqueous and oil-rich systems, as an anti-caking and flow aid, and as an absorbent and bulking agent.

Frequently Asked Questions

What does silica dimethyl silylate do?

Silica Dimethyl Silylate (CAS 68611-44-9) is a hydrophobic fumed silica that acts as a rheology modifier and anti-settling thickener in non-aqueous and oil-rich systems. It also functions as an anti-caking and flow aid for powders and as an absorbent and bulking agent.

Is silica dimethyl silylate the same as dimethicone?

No. Silica dimethyl silylate is a synthetic amorphous fumed silica whose surface has been treated with dimethylsilyl groups to make it hydrophobic, so it is a solid particulate. Dimethicone is a liquid polydimethylsiloxane (PDMS) fluid. They are chemically distinct materials with different functions.

What is silica dimethyl silylate made from?

It is made by surface-treating synthetic amorphous fumed silica (silicon dioxide) with dimethylsilyl groups, which renders the particle surface hydrophobic. The result is a treated fumed silica used for rheology control and anti-settling in oil-rich systems.

What is the HS code for silica dimethyl silylate?

It classifies under HS 2811.22 (Silicon dioxide). Confirm the destination-country tariff line with your customs broker, as national subheadings can extend beyond the six-digit HS code.

Can silica dimethyl silylate be supplied in bulk?

Yes. RawSource supplies silica dimethyl silylate in bulk quantities to coatings, adhesive, and personal-care manufacturers. Request a quote with your target volume and packaging; CoA and SDS are available on request.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.