AEROSIL 300 is a hydrophilic fumed silica from Evonik with a specific BET surface area of 270-330 m²/g, giving it a notably strong rheological effect compared with lower-surface-area fumed silica grades. For composite material buyers and coating formulators sourcing anti-sag, anti-settling, and thixotropic additives, it is a standard reference grade used across paints and coatings, unsaturated polyester resin (UPR) systems, adhesives and sealants, and silicone rubber compounds.
Key Technical Properties of AEROSIL 300
According to Evonik’s official technical data sheet, this fumed silica grade is characterized by the following properties, which buyers should confirm against their own incoming-goods testing:
| Specific surface area (BET) | 270 – 330 m²/g |
| pH value | 3.7 – 4.5 |
| SiO2 content | >99.8% |
| Loss on drying | <1.5% |
| Tamped density | Approx. 50 g/l |
| Recommended addition level | 1.0 – 2.0% of total formulation, as supplied |
| Shelf life | 24 months from date of manufacture |
| Packaging | Multi-layer 10 kg bags |
| CAS number | 112945-52-5 / 7631-86-9 |
Why Buyers Choose This Fumed Silica for Rheology Control
Evonik lists the key effects of this product as rheology control, thixotropy, reinforcement, free-flow, and anti-caking. In coating systems specifically, the product is documented to deliver:
- Anti-settling performance that keeps pigments and fillers suspended during storage
- Anti-sagging control that helps formulations hold film thickness on vertical surfaces
- Support for corrosion resistance in protective coating formulations
- Higher efficiency and high transparency after good dispersion, as noted in Evonik’s technical literature
Suitability Across Coating Systems
Per Evonik’s technical data sheet, it is positioned across waterborne, solventborne, radiation-curing, one-pack, and two-pack coating systems, with suitability levels that vary by system. Buyers and formulators should confirm compatibility with their specific base resin before moving to production scale-up, and addition is possible either directly as supplied or as a predilution.
Typical Applications for AEROSIL 300
Evonik’s product documentation names wood coatings and plastic coatings as typical applications, while the broader product listing extends its use to several other formulation types relevant to auxiliary agents used in composite and coating manufacturing:
- Wood coatings and plastic coatings
- Paints and coatings generally, including anti-sag and anti-settling formulations
- Unsaturated polyester resin (UPR) systems used in FRP and composite manufacturing
- Adhesives and sealants
- HTV and LSR silicone rubber, and cable compounds
Sourcing This Fumed Silica Grade for Composite and Coating Formulations
As a recommended international brand product, it is available through supply chain resource support for overseas buyers who need consistent fumed silica performance across production lots. Because the product’s rheological behavior depends on dispersion quality and addition level, buyers sourcing this grade for UPR, gelcoat, adhesive, or coating formulations should request a current certificate of analysis for each shipment and verify BET surface area, pH, and loss-on-drying figures against Evonik’s official product documentation before full-scale use.
FAQ
What is the BET surface area of AEROSIL 300?
Evonik’s technical data sheet lists the specific surface area (BET) of AEROSIL 300 at 270 – 330 m²/g.
What is the recommended addition level for this product?
Evonik recommends an addition level of 1.0 – 2.0% of total formulation, as supplied, with addition possible directly or as a predilution.
Is AEROSIL 300 suitable for unsaturated polyester resin systems?
Yes, unsaturated polyester resins are listed among the typical applications for AEROSIL 300 in Evonik’s product documentation, alongside paints, coatings, adhesives and sealants.
How should AEROSIL 300 be stored?
AEROSIL 300 should be stored in its original unopened packaging under dry conditions, away from volatile substances, and has a shelf life of 24 months from the date of manufacture.
How can I request a quote or sample of AEROSIL 300?
Contact our team with your target application and required volume, and we will provide sourcing and supply chain resource support based on current availability.
Looking to source AEROSIL 300 for your next coating, UPR, or adhesive formulation? Contact our team today with your application details and volume requirements, and we will help connect you with the right supply chain resources.
