Hydrophobic fumed silica, surface treated with hexamethyldisilazane. The treated surface resists moisture pick-up, keeps viscosity stable on storage, and disperses more easily in non-polar and reactive systems than untreated grades. Specific surface area 170 m2/g.
Product Code
AC-HB620
Fumed Silica AC-HB620 — Hydrophobic
CAS Number
112945-52-5
Description
Synonyms
Key applications
- Thixotropy and sag control in sealants and adhesives
- Reinforcement of silicone rubber
- Anti-settling in paints and inks
- Rheology control in resins and gel coats
- Free-flow and anti-caking
Characteristics
| Type | Hydrophobic |
|---|---|
| Surface area | 170 m2/g |
| pH (4% dispersion) | ≥7.0 |
| Surface treatment | HMDS |
| Molecular formula | SiO2 |
| Molecular weight | 60.08 g/mol |
| pH | >/=7.0 |
| Melting point | No sharp melting point — softens/sinters at ≈1200°C (glass transition) |
| Density | ≈2.2 g/cm³ (true particle density; bulk density is grade-dependent) |
| Appearance | White, fluffy/loose powder |
| Flash point | Not applicable — non-combustible inorganic solid |