REOLOSIL QS-20L is a hydrophilic fumed silica grade manufactured by Tokuyama Corporation, supplied through Thousands Technology for composite, coating, and adhesive formulators sourcing a verified rheology control additive. REOLOSIL QS-20L is an untreated, high-purity amorphous silica produced by a high-temperature gas-phase process, which gives it a large specific surface area, a loose agglomerate structure, and reliable thickening and anti-sag performance once dispersed into a resin system. For overseas buyers comparing fumed silica suppliers for FRP, coatings, and adhesive production, it offers a documented, manufacturer-verified specification sheet that supports consistent batch-to-batch formulation.
REOLOSIL QS-20L Technical Specifications
According to Tokuyama’s published REOLOSIL grade data, this grade is the low-bulk-density variant within the QS-20 series, offering the same particle fineness as QS-20 with lower packing density for easier incorporation. The table below lists the manufacturer-confirmed properties.
| Property | Typical Value |
|---|---|
| Appearance | White fine powder |
| BET Specific Surface Area | 220 ±20 m²/g (before surface treatment) |
| Primary Particle Size | Approx. 12 nm |
| Bulk Density | Approx. 45 g/L (low-bulk-density grade) |
| Moisture Content (Dry Up) | < 1.5% |
| pH (4% Aqueous Suspension) | 4.2 |
| SiO2 Purity | > 99.9% |
| Cl Content | < 50 ppm |
| Fe Content | < 20 ppm |
| Al Content | < 20 ppm |
| 325 Mesh Residue | < 0.01% |
| Packaging | 10 kg bags (standard) |
These values are published by Tokuyama for the QS-20/QS-20L surface-treatment grade and are not altered or estimated by Thousands Technology; buyers requesting a certificate of analysis for a specific lot of this fumed silica grade should confirm current batch data directly with the supplier.
Why this product Is Classified as a Hydrophilic Grade
REOLOSIL QS-20L belongs to the untreated, hydrophilic branch of the REOLOSIL series. Unlike the hydrophobic grades (MT, DM, HM, PM, X series), which carry a surface treatment such as dimethyldichlorosilane, hexamethyldisilazane, or silicone oil, the material retains its native silanol-rich surface. This surface chemistry is what allows fumed silica to build a hydrogen-bonded particle network once it is sheared into a liquid resin, producing the shear-thinning, anti-sag behavior that formulators rely on. Per Tokuyama’s technical guidance, hydrophilic grades such as this additive are particularly effective under low-dispersion conditions in polar resins, or under high-dispersion conditions in non-polar resins, making grade selection dependent on both the resin polarity and the mixing equipment available on the production line.
Where it Fits in Composite and Coating Formulations
Because this grade is a fine, high-surface-area fumed silica, it is positioned by the manufacturer as a rheology and anti-settling additive for liquid resin and coating systems rather than as a structural filler. Tokuyama’s own grade-family testing (conducted at 2.5 PHR in polyester resin and 3 PHR in epoxy resin, under controlled dispersion mixer and homo-mixer conditions) shows that fumed silica in the QS/PM/HM family imparts measurable thickening and thixotropic effect to both polyester and epoxy systems, supporting anti-drip and anti-sag performance after application. For FRP pipe and tank producers, gelcoat formulators, filament winding operations, and hand lay-up shops, this translates into better vertical-surface hold and reduced resin migration before cure. Sourcing managers should confirm with their formulation chemist whether the low-bulk-density characteristic of REOLOSIL QS-20L (versus the standard QS-20 grade) changes dosing or mixing time in their specific resin system.
Typical Application Areas for this fumed silica grade
- Unsaturated polyester and vinyl ester resin systems requiring sag resistance
- Epoxy resin formulations for coatings and composite tooling
- Gelcoat and topcoat rheology adjustment
- Adhesive and sealant anti-settling control
As with any fumed silica grade, performance in a specific formulation depends on dispersion equipment, shear rate, and the base resin’s own polarity, so buyers evaluating this product for a new application are encouraged to request a small-batch trial before committing to volume purchasing.
Sourcing the material Through Thousands Technology
Thousands Technology supplies REOLOSIL QS-20L as part of its auxiliary agent and additive range for composite material buyers, alongside related rheology modifiers and curing systems. Working with a documented, manufacturer-traceable grade such as this additive helps FRP factories, pultrusion plants, and coating formulators avoid the quality variability that can come with unverified or relabeled fumed silica. For technical questions on handling, dosing, or compatibility testing, buyers can reference the ASTM Committee D20 resources on plastics testing standards, available at ASTM International, alongside the supplier’s own documentation for it.
Frequently Asked Questions About REOLOSIL QS-20L
Is this grade hydrophilic or hydrophobic?
this fumed silica grade is an untreated, hydrophilic fumed silica grade. It does not carry a surface treatment, so its particle surface remains silanol-rich.
What distinguishes this product from standard QS-20?
Both share the same 220 ±20 m²/g BET surface area and 12 nm primary particle size. The “L” designation on the material indicates a lower bulk density grade, which can affect how quickly it incorporates during mixing.
Which resin systems is REOLOSIL QS-20L suited for?
As a hydrophilic grade, it is positioned for polar or moderately polar resin systems such as unsaturated polyester, vinyl ester, and epoxy, where it is used for thickening, anti-sag, and anti-settling control.
Does Thousands Technology provide a certificate of analysis for this additive?
Buyers can request current batch documentation and technical data sheets for it directly through an inquiry; specific lot values may vary slightly within the manufacturer’s published specification range.
How is REOLOSIL QS-20L typically packaged for export?
The grade is commonly supplied in 10 kg bags, consistent with Tokuyama’s standard packaging for this surface-treatment family; buyers with different packaging needs should confirm availability at the time of inquiry.
To request a quotation or technical data sheet for this grade, or to discuss dosing for a specific resin system, contact Thousands Technology’s sourcing team with your target application and expected order volume.
