SEMISIL 300 Hydrophilic Fumed Silica
SEMISIL 300 is a high-purity hydrophilic fumed silica with a specific surface area of 300 m²/g — the highest thickening efficiency in the SEMISIL hydrophilic series. Its ultra-fine primary particle size and dense silanol network deliver maximum gelation and anti-sag performance in liquid silicone rubber, high-viscosity sealants, and cosmetic gel formulations where lower-surface-area grades cannot achieve the required consistency.
Technical Specifications
| Properties and Test Methods | Unit | Typical Value | Standardization |
|---|---|---|---|
| Specific surface area (BET) | m²/g | 300 ± 30 | GB/T 10722 |
| pH value (in 4% dispersion) | – | 3.6 ~ 4.3 | GB/T 1717 |
| Loss on drying (2h @ 105°C) | Wt% | ≤ 1.5 | GB/T 5211.3 |
| Loss on ignition (2h @ 1000°C, based on dried material) | Wt% | ≤ 2.5 | GB/T 20020 |
| Sieve residue (45 μm) | % | ≤ 0.05 | GB/T 5211.14 |
| Silica content (ignited material) | Wt% | ≥ 99.8 | GB/T 20020 |
| Tamped density (dried material) | g/L | 20 ~ 35 | GB/T 5211.4 |
| Carbon content (dried material) | Wt% | ≤ 0.2 | GB/T 20020 |
Application Suggestions
Liquid Silicone Rubber (LSR) and HTV Silicone
Delivers maximum reinforcement and optical clarity in liquid silicone rubber compounds. The high surface area provides exceptional tensile strength (>8 MPa) and elongation in transparent LSR, making it the preferred grade for optical-quality silicone encapsulants and medical-grade LSR parts.
High-Viscosity RTV Sealants
Acts as an ultra-efficient anti-sag and thickening agent in one- and two-part RTV silicone sealants. A lower loading (2–4%) achieves the same sag resistance as 5–8% of SEMISIL 200, improving processing efficiency and reducing formulation cost.
Cosmetic Gels and Creams
Provides a firm, stable gel structure in high-end cosmetic serums, eye gels, and clear gel formulations. The high surface area generates a strong silanol hydrogen-bonding network, producing transparent gels with long shelf-life stability without syneresis.
Pharmaceutical Excipient (Glidant)
An ultra-fine flow enhancer for pharmaceutical direct-compression tablets where active ingredients are extremely cohesive. The high surface area ensures maximum surface coverage per gram, making it effective at loadings as low as 0.1–0.2%.
Technical Support & FAQ: SEMISIL 300
+Q1: What are the key features and applications of SEMISIL 300?
SEMISIL 300 Fumed Silica is engineered for applications demanding maximum thickening power:
- Core Functions: Maximum thickening, gelation, anti-sag, and reinforcement
- Key Features: BET 300 m²/g, ultra-low tamped density (20–35 g/L), exceptional silanol density
- Primary Applications: LSR and HTV silicone rubber, high-viscosity RTV sealants, clear cosmetic gels, pharmaceutical glidant
+Q2: How does SEMISIL 300 compare with other SEMISIL grades?
| Grade | BET (m²/g) | Tamped Density (g/L) | Best For |
|---|---|---|---|
| SEMISIL 110 | 100–120 | 40–60 | Easy dispersion, low-viscosity systems |
| SEMISIL 200 | 175–225 | 40–60 | General purpose, sealants, coatings |
| SEMISIL 300 | 270–330 | 20–35 | Maximum thickening, LSR, clear gels |
Equivalent to: AEROSIL® 300 (Evonik), CAB-O-SIL® M-7D (Cabot).
+Q3: What factors influence the pricing of SEMISIL 300?
- Production Costs: Higher SiCl₄ consumption per unit mass and extended flame hydrolysis residence time vs. lower-BET grades
- Quality Standards: Strict BET ±30 m²/g tolerance and low tamped density control
- Logistics: Vacuum-densified bags required; lower kg/pallet than SEMISIL 200 due to very low bulk density
+Q4: What are the typical lead times and payment terms?
- Lead Time: Typically 7–14 days (Annual supply volume: 15,000 tons)
- Payment Terms: Flexible options including T/T, L/C at sight, and D/P
- Sample Support: Free samples (200g–1kg) available for R&D evaluation
Packing & Storage Information
Storage Conditions
SEMISIL® 300 should be stored in closed containers under dry conditions and protected from volatile substances. Due to its extremely low bulk density, avoid compression during storage. Use within 2 years of manufacture date.