A grade-by-grade technical comparison of SEMISIL and Tokuyama Reolosil fumed silica for coatings, adhesives, and sealant formulators.
A grade-by-grade technical comparison of SEMISIL and Tokuyama Reolosil fumed silica for coatings, adhesives, and sealant formulators.
Both SEMISIL and Tokuyama Reolosil are pyrogenic (fumed) silica product families manufactured via the chlorosilane flame hydrolysis process. Reolosil is produced at Tokuyama Corporation’s facilities in Tokuyama, Yamaguchi Prefecture, Japan, and distributed primarily across East and Southeast Asia. SEMISIL is manufactured in China with global distribution and a grade portfolio engineered to match the most widely specified BET surface areas.
The critical buying decision hinges on whether a direct grade-for-grade substitute exists. For the dominant 200 m²/g specification — the workhorse grade in epoxy, polyester, and silicone systems — SEMISIL 200 maps directly against Reolosil QS-20. Both deliver ≥99.8% SiO₂ purity and comparable primary particle size distributions around 12 nm.
Both brands use the same core chemistry: SiCl₄ is vaporized and fed into an oxyhydrogen flame at 1000–1800 °C, producing amorphous SiO₂ nanoparticles that aggregate into fractal chain structures. This flame hydrolysis process determines three critical downstream parameters — BET surface area, aggregate morphology, and residual HCl content.
Tokuyama’s single-site Japanese production yields tight lot-to-lot consistency, with residual chloride typically held below 100 ppm. SEMISIL production uses the same SiCl₄ feedstock route and achieves comparable chloride levels (≤150 ppm typical, ≤250 ppm spec limit). For most adhesive and coatings applications, both figures are well within acceptable limits. Pharmaceutical or electronic-grade uses requiring ≤50 ppm Cl⁻ should request a certificate of analysis either way.
In practical formulation work, the performance gap between grade-matched SEMISIL and Reolosil is narrow. At 2–3 wt% loading in a bisphenol-A epoxy resin (viscosity baseline ~12 Pa·s at 25 °C), both SEMISIL 200 and Reolosil QS-20 raise thixotropic index to the 4.5–6.0 range — adequate for vertical-surface anti-sag in structural bonding. Dispersion behavior under high-shear mixing (tip speed ≥15 m/s for 10–15 minutes) is essentially identical.
Where differentiation appears is in surface treatment grades. Tokuyama offers DM-series (dimethyldichlorosilane-treated) and HM-series (hexamethyldisilazane-treated) hydrophobic variants. SEMISIL’s hydrophobic portfolio covers both HMDS and DDS treatment routes, giving formulators broader selection when optimizing moisture resistance in silicone sealants or controlling foam in liquid silicone rubber.
Reolosil pricing reflects Japanese manufacturing cost structures and a distribution network that adds margin layers outside Japan. CIF Southeast Asia pricing for QS-20 typically sits in the $3,800–4,500/MT range depending on volume and contract terms (2025–2026 indicative). SEMISIL 200 is available at $2,400–3,100/MT CIF for equivalent volumes, representing a 30–45% cost advantage driven by lower energy and labor input costs in Chinese production.
Lead times also diverge. Tokuyama runs allocation-based ordering with 6–10 week lead times for non-Japanese buyers, and supply disruptions (such as the 2024 logistics constraints through the Strait of Malacca) can extend this further. SEMISIL maintains 2–4 week delivery ex-China to most Asian ports, with European and North American warehousing reducing effective lead time to 1–2 weeks for stocked grades.
The table below compares the most commonly specified hydrophilic grades side by side. All values are nominal; consult the relevant technical data sheet for lot-specific certificates of analysis. For a deeper comparison across BET grades, see our guide to BET 150 vs 200 vs 300 vs 380 surface area differences.
| Parameter | SEMISIL 200 | Reolosil QS-20 | Test Method |
|---|---|---|---|
| BET Surface Area | 200 ± 25 m²/g | 200 ± 30 m²/g | ISO 9277 |
| SiO₂ Content | ≥99.8% | ≥99.8% | Gravimetric |
| Tamped Density | ~50 g/L | ~50 g/L | DIN EN ISO 787-11 |
| Loss on Drying (2 h, 105 °C) | ≤1.5% | ≤1.5% | ISO 787-2 |
| Loss on Ignition (2 h, 1000 °C) | ≤1.0% | ≤1.0% | DIN 55921 |
| pH (4% dispersion) | 3.7–4.7 | 3.6–4.5 | ISO 787-9 |
| Residual Chloride (as HCl) | ≤250 ppm | ≤250 ppm | Titration |
| Primary Particle Size | ~12 nm | ~12 nm | TEM |
| CIF Price Range (Asia) | $2,400–3,100/MT | $3,800–4,500/MT | — |
For the dominant 200 m²/g grade, SEMISIL 200 matches Reolosil QS-20 on every critical specification — BET, purity, pH, and tamped density — while offering 30–45% lower CIF pricing and significantly shorter lead times. It is a direct drop-in for formulators currently sourcing Tokuyama.
Yes, SEMISIL 200 is a drop-in replacement for Reolosil QS-20. Both are hydrophilic fumed silica with 200 m²/g BET surface area, ≥99.8% SiO₂ purity, and ~12 nm primary particle size. No reformulation is needed when switching at the same loading level.
Reolosil pricing reflects higher Japanese manufacturing costs (energy, labor) and multi-layer distribution margins for non-Japanese buyers. SEMISIL’s Chinese production base and direct export model reduce CIF cost by 30–45% at equivalent purity and BET specifications.
Reolosil offers QS-10 (130 m²/g), QS-20 (200 m²/g), QS-30 (300 m²/g), and QS-40 (400 m²/g). SEMISIL matches with grades at 130, 200, 300, and 380 m²/g. The 200 m²/g grade is the highest-volume product in both lines.
SEMISIL ships within 2–4 weeks ex-China, with 1–2 week delivery from stocked European and North American warehouses. Reolosil typically requires 6–10 weeks for non-Japanese buyers due to allocation-based ordering and single-source production in Japan.
SEMISIL hydrophilic grades meet USP/NF and EP monograph specifications for colloidal silicon dioxide. Request a certificate of analysis confirming residual chloride ≤100 ppm and heavy metals compliance for regulated applications. The same applies to Reolosil.
At 2–3 wt% in epoxy resin, both SEMISIL 200 and Reolosil QS-20 produce a thixotropic index of 4.5–6.0. In alkyd coatings at 3 wt%, both exceed 5.0. Performance is functionally equivalent when dispersion conditions (tip speed ≥15 m/s, 10–15 min) are matched.
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