Description

Aerosil R 805 is a hydrophobic fumed silica, chemically modified with octylsilane. This surface treatment imparts exceptional moisture resistance and compatibility with organic systems, making it a critical performance additive. It is essential for formulators seeking to control rheology, prevent caking, and enhance the mechanical properties of composites and coatings. Key industries that rely on this material include paints & coatings, adhesives & sealants, silicone rubber, and advanced polymer composites.

Application

• Rheology Control and Anti-Sagging Agent in solvent-based paints, coatings, and printing inks.
• Reinforcing Filler and Thixotrope in silicone sealants, adhesives, and high-consistency rubber (HCR).
• Free-Flow and Anti-Caking Agent for powders, including construction chemicals, fertilizers, and food-contact materials where hydrophobicity is required.
• Viscosity Modifier and Stabilizer in gel coats, unsaturated polyester resins (UPR), and epoxy systems.
• Matting Agent in industrial and wood coatings to achieve a controlled, uniform surface finish.
• Carrier and Dispersant for active ingredients in agrochemicals and pharmaceutical preparations.
• Component in Thermal Insulation Composites, such as aerogels, due to its hydrophobic and low-density properties.

Basic Information

Product Name	Aerosil R 805
CAS No.	112153-70-5
Molecular Formula	SiO₂ (surface modified with C₈H₁₇ groups)
Molecular Weight	Contact for details
Synonyms	Hydrophobic Fumed Silica; Octylsilane-treated Silica; Fumed Silicon Dioxide, Hydrophobic; Silica, Fumed, Reaction Products with Octylsilane; CAB-O-SIL TS-720 (comparable grade); HDK H20 (comparable grade); Wacker HDK® H20; Hydrophobic Silicone Dioxide
EINECS	Contact for details

Quality Control

Our Aerosil R 805 is manufactured under a stringent quality management system. Each batch is tested against critical parameters to ensure consistent performance, including specific surface area (BET), carbon content, loss on drying, and tamped density. A Certificate of Analysis (COA) documenting these results is provided with every shipment to guarantee traceability and compliance with your specifications.

Storage

Preserve in a tightly closed container, protected from light. This product is hygroscopic (moisture-sensitive). Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep the container tightly sealed when not in use to prevent moisture absorption, which can affect product performance.

Specification

Item	Specification
Appearance	White, fluffy powder
Specific Surface Area (BET)	150 ± 25 m²/g
Carbon Content	4.5 - 6.0 %
Loss on Drying (2 hrs @ 105°C)	≤ 0.5 %
pH (in 4% aqueous dispersion)	3.7 - 4.7
Tamped Density	Approx. 50 g/l
Sieve Residue (on 45 μm)	≤ 0.05 %

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.