Censil fumed silica - high surface area precipitated silica for adhesives, sealants, coatings, rubber & personal care. Rheology modifier, thickener & reinforcement. Alternative to Aerosil & Cab-O-Sil. Free sample.
Characteristic: It is a white and colloidal micro-particle with its primary micro-particle from 5-40 nm and has properties such as thixotropy, reinforcing, thickening and filling etc.
and is insoluble in all kinds of solvents and liquids except hydrofluoric acid and concentrated bases.
Appreance:Powder
Package：10kg/Paper bag
1. High properties: This series' products are popular for their favorable price,good quality and high properties
2. Excellent thixotropy, thickening anti-settling
3. Easy dispersion brings unique coating appearance properties
Application：
Censil-150:It is mainly used for acidic silicone rubber, RTV silicone rubber (low moisture content) and neutral silicone rubber.
Censil-200:It is mainly used for high-temperature vulcanized silicone rubber, organic silicone defoamer, advance printing ink, powder coating, PVC resin, unsaturated polyester resin thickening, thixotropic agent, pharmaceutical powder, tabular preparation, cosmetics etc.
Censil-300:It is mainly used for silicone rubber, silicone grease and sealing materials of capacitance packaging with high transparency and high tear resistance.
Censil-380:It is mainly used for printing ink (copy toner), coating, plastic, toothpaste, food, medicine, cosmetics, silicone rubber, sealant, adhesive, gel battery composite material, industriallubricating oil, unsaturated polyester resin, layered resin and gel coat, insulation glue of cable and cable gel, thickener of synthetic grease, plant protection etc.
Specification |
CENSIL 150 |
CENSIL 200 |
CENSIL 300 |
CENSIL 380 |
Appearance | White Powder | White Powder | White Powder | White Powder |
Whiteness | 98 | 98 | 98 | 98 |
Heating loss (105°C 2h) % | 0.5-1.0 | ≤1.5 | ≤1.5 | ≤1.5 |
Ignition Loss 1000°C 2h (Dry Basis) % | 1.0-2.0 | ≤2.0 | ≤2.0 | ≤2.5 |
DBP(Oil absorption value) cm3/g | - | ≥180 |
| ≥180 |
PH value(5% Aqueous Suspension) | 3.5-4.5 | 3.5-4.5 | 3.5-4.5 | 3.5-5.5 |
SiO2(Dry Basis) % | ≥99.9 | ≥99.9 | ≥99.9 | ≥99.9 |
BET Specific Surface Area m2/g | 150+15 | 200+25 | 300+25 | ≥365 |
Particle size | 14-20 | 14-20 | 14-20 | 14-20 |
Bulk density m2/g | 40-50 | 40-50 | - | - |
Censil fumed silica offers equivalent performance to leading brands at competitive pricing:
| Censil Grade | BET (m²/g) | SiO₂ Purity | Comparable Products |
|---|---|---|---|
| Censil 150 | 150±15 | ≥99.9% | Cab-O-Sil M-5, Aerosil 150 |
| Censil 200 | 200±25 | ≥99.9% | Cab-O-Sil LM-150, Aerosil 200 |
| Censil 300 | 300±25 | ≥99.9% | Cab-O-Sil M-5P, Aerosil 300 |
| Censil 380 | 380±30 | ≥99.9% | Cab-O-Sil EH-5, Aerosil 380 |
Censil is a Chinese manufacturer of fumed silica (gas phase silica), produced by Longyan Shenghe Chemical Co., Ltd. in Fujian, China. Censil fumed silica is manufactured through flame pyrolysis (gas-phase process) of silicon tetrachloride, yielding ultra-pure amorphous SiO₂ with ≥99.9% purity and BET surface areas ranging from 150 to 380 m²/g.
As a leading fumed silica powder supplier, Censil serves formulators and manufacturers across adhesives, sealants, coatings, composites, cosmetics, and pharmaceutical industries. With 4 standard grades — Censil 150, Censil 200, Censil 300, and Censil 380 — Censil covers the full spectrum of fumed silica applications from general-purpose rheology modification to high-performance thickening and reinforcement. Censil fumed silica is a cost-effective alternative to Aerosil, Cab-O-Sil, and HDK brands, offering 20-35% cost savings with equivalent performance.
Censil fumed silica is widely used as a fumed silica rheology modifier for adhesives and a fumed silica thickener for sealants. By forming a three-dimensional hydrogen-bonded network within the liquid matrix, Censil fumed silica provides excellent thixotropic behavior — the formulation is thick at rest (preventing sag and slump) but flows easily under shear during application.
| Adhesive/Sealant Type | Recommended Censil Grade | Typical Dosage | Key Benefits |
|---|---|---|---|
| Silicone Sealants (RTV-1, RTV-2) | Censil 200 / Censil 300 | 2-5% | Anti-sag, thixotropy, reinforcement |
| Polyurethane Adhesives | Censil 200 | 1-3% | Viscosity control, anti-settling |
| Epoxy Adhesives & Coatings | Censil 150 / Censil 200 | 0.5-2% | Anti-sag on vertical surfaces |
| MS Polymer Sealants | Censil 200 / Censil 300 | 2-4% | Thixotropy, non-slip in bead application |
| Hot Melt Adhesives | Censil 150 | 1-3% | Anti-drip, open time control |
| Solvent-Based Adhesives | Censil 200 | 1-4% | Rheology control, filler suspension |
| Construction Sealants (PU, Silicone) | Censil 300 / Censil 380 | 3-6% | High anti-sag for deep joints |
As a fumed silica thickener for sealants, Censil fumed silica prevents bead slump and ensures clean application even in overhead and vertical joint sealing. The high surface area grades (Censil 300, Censil 380) deliver stronger rheological effects at lower dosages, making them ideal for high-performance construction sealants and structural silicone systems.
Censil fumed silica serves as a multi-functional additive in coatings and composite materials. In coatings, it acts as a rheology modifier, Matting Agent, and anti-settling additive. In composite systems (FRP, SMC/BMC, unsaturated polyester resins), Censil fumed silica provides viscosity build-up, reinforcement, and thixotropic behavior essential for vertical surface application.
| Application | Recommended Grade | Typical Dosage | Function |
|---|---|---|---|
| Anti-corrosion Coatings | Censil 150 / Censil 200 | 0.5-2% | Anti-sag, anti-settling of zinc/micaceous iron oxide |
| Powder Coatings | Censil 150 | 0.5-1.5% | Free-flow agent, anti-caking |
| UV/EB Curable Coatings | Censil 200 | 0.5-2% | Rheology control, pigment suspension |
| FRP / GRP (Fiberglass Reinforced Plastics) | Censil 200 / Censil 300 | 1-3% | Thixotropic agent for vertical layup |
| SMC/BMC (Sheet/Bulk Molding Compounds) | Censil 300 | 1-2.5% | Viscosity profile control |
| Unsat. Polyester Gel Coats | Censil 200 / Censil 300 | 1-3% | Anti-sag on mold surfaces |
| Marine & Industrial Topcoats | Censil 200 | 0.5-1.5% | Sag resistance, matting effect |
For composite manufacturing, Censil fumed silica ensures that resin systems maintain their viscosity profile during layup, preventing resin drainage on vertical surfaces. In industrial coatings, it provides reliable anti-settling of heavy pigments like zinc dust and micaceous iron oxide, extending pot life and reducing re-mixing requirements.
Censil fumed silica, with its ≥99.9% SiO₂ purity, is suitable for use in cosmetics and personal care products as a thickener, anti-caking agent, and free-flow agent. The ultra-fine particle structure provides excellent oil absorption and matte-finish properties in cosmetic formulations.
| Application | Recommended Grade | Dosage | Function |
|---|---|---|---|
| Foundation & Compact Powders | Censil 150 | 2-10% | Anti-caking, oil absorption, matte finish |
| Lipstick & Lip Gloss | Censil 200 | 1-5% | Rheology modification, pigment suspension |
| Sunscreen & SPF Products | Censil 200 | 1-3% | UV filter suspension, texture improvement |
| Hair Care (Styling Gel, Wax) | Censil 150 | 0.5-3% | Thickening, texture control |
| Deodorant Sticks | Censil 150 | 1-4% | Structuring agent, anti-sweat moisture control |
| Dry Shampoo | Censil 150 | 5-15% | Oil absorption, sebum control |
Censil fumed silica for cosmetics provides high purity (SiO₂ ≥99.9%, heavy metals <10 ppm) meeting the requirements for personal care applications. As a fumed silica for cosmetics, it enhances product stability, improves spreadability, and delivers a silky, non-greasy skin feel.
Censil offers 4 grades of fumed silica (gas phase silica) with BET surface areas from 150 to 380 m²/g, covering the full range of fumed silica applications. All grades share ≥99.9% SiO₂ purity, produced through flame pyrolysis for consistent quality and performance.
| Property | Censil 150 | Censil 200 | Censil 300 | Censil 380 |
|---|---|---|---|---|
| Appearance | White powder | White powder | White powder | White powder |
| SiO₂ Content (dry basis) | ≥99.9% | ≥99.9% | ≥99.9% | ≥99.9% |
| BET Surface Area (m²/g) | 150 ± 15 | 200 ± 25 | 300 ± 25 | 380 ± 30 |
| Primary Particle Size (nm) | ~20 | ~12 | ~7 | ~7 |
| pH (5% suspension) | 3.5-4.5 | 3.5-4.5 | 3.5-4.5 | 3.5-5.5 |
| Loss on Drying (105°C, 2h) % | ≤1.0 | ≤1.0 | ≤1.5 | ≤1.5 |
| Loss on Ignition (1000°C, 2h) % | 1.0-2.0 | 1.0-2.0 | ≤2.0 | ≤2.5 |
| DBP Absorption (ml/100g) | — | — | — | ≥180 |
| Bulk Density (g/L) | 40-50 | 40-50 | 30-40 | 30-40 |
| Whiteness | 98 | 98 | 98 | 98 |
| Particle Size (aggregate, µm) | 14-20 | 14-20 | 14-20 | 14-20 |
| Typical Applications | General-purpose thickener, cosmetics, powder coatings | Adhesives, sealants, FRP, coatings — all-purpose | High-performance sealants, composites, construction | Maximum rheology control, specialty applications |
Formulators evaluating fumed silica suppliers often compare Censil against leading international brands. Below is a specification-level comparison showing how Censil matches international standards while offering significant cost advantages as a China-based fumed silica manufacturer.
| Property | Censil 200 | Aerosil® 200 | Cab-O-Sil® M5 | HDK® H20 |
|---|---|---|---|---|
| SiO₂ Content | ≥99.9% | ≥99.8% | ≥99.8% | ≥99.8% |
| BET Surface Area | 200 ± 25 m²/g | 200 ± 25 m²/g | 200 ± 50 m²/g | 200 ± 30 m²/g |
| pH (5% suspension) | 3.5-4.5 | 3.6-4.3 | 3.6-4.3 | 3.6-4.5 |
| Loss on Drying (105°C) | ≤1.0% | ≤1.5% | ≤1.5% | ≤1.5% |
| Loss on Ignition (1000°C) | 1.0-2.0% | ≤2.0% | ≤2.5% | ≤2.5% |
| Bulk Density (g/L) | 40-50 | ~50 | ~32 | ~50 |
| Primary Particle Size | ~12 nm | 12 nm | 12 nm | 12 nm |
| Cost Index | 100 | 130-150 | 125-145 | 130-150 |
| Lead Time | 2-3 weeks | 6-10 weeks | 4-8 weeks | 6-10 weeks |
| BET (m²/g) | Censil Grade | Aerosil® Equivalent | Cab-O-Sil® Equivalent | HDK® Equivalent |
|---|---|---|---|---|
| ~150 | Censil 150 | Aerosil® 150 | Cab-O-Sil® LM-150 | HDK® H15 |
| ~200 | Censil 200 | Aerosil® 200 | Cab-O-Sil® M5 | HDK® H20 |
| ~300 | Censil 300 | Aerosil® 300/380 | Cab-O-Sil® MS-75D | HDK® H30 |
| ~380 | Censil 380 | Aerosil® 380 | Cab-O-Sil® M5P | HDK® H40 |
Key Finding: Censil fumed silica matches international brands in all critical parameters — SiO₂ purity (≥99.9%), BET surface area, pH, and loss on drying — while offering 20-35% cost savings and significantly shorter lead times. For formulators seeking an alternative to Aerosil 200, a Cab-O-Sil M5 alternative, or an HDK H20 alternative, Censil provides drop-in replacement capability without reformulation.
Proper dispersion of fumed silica powder is critical to achieving the desired rheological performance. Unlike dissolving, fumed silica must be fully wetted and distributed into the liquid matrix to activate its thixotropic properties. Here is a practical guide on how to disperse fumed silica effectively.
| Step | Action | Details |
|---|---|---|
| 1. Equipment Selection | Use a high-speed dissolver or rotor-stator mixer | Tip speed: 15-25 m/s (1,500-3,000 rpm for standard dissolvers). Cowles blade or saw-tooth disc recommended. |
| 2. Gradual Addition | Add fumed silica slowly to the liquid phase | Add in small increments over 5-10 minutes. Never dump the entire quantity at once — this creates fisheyes and incomplete wetting. |
| 3. High-Shear Mixing | Mix at high speed for 10-30 minutes | Continue mixing until the batch is homogeneous and lump-free. Temperature will rise — monitor to avoid exceeding the thermal limit of the formulation. |
| 4. Rest Period (Optional) | Allow 12-24 hours for full thixotropic development | The hydrogen-bond network takes time to fully develop. Viscosity readings taken immediately after mixing will be lower than the final equilibrium value. |
| 5. Verification | Check viscosity and thixotropic index | Measure viscosity at low shear (0.1-1 s⁻¹) and high shear (100-1000 s⁻¹). The ratio (thixotropic index) indicates the degree of structure development. |
| System Type | Dispersion Tips |
|---|---|
| Polar Systems (water-based, glycols, polyols) | Fumed silica disperses relatively easily in polar liquids due to surface silanol groups. Standard high-shear mixing is usually sufficient. |
| Non-Polar Systems (hydrocarbon solvents, mineral oil, silicone oil) | Untreated fumed silica disperses well in non-polar systems. For hydrophobic systems, consider using surface-treated (hydrophobic) fumed silica grades for better compatibility. |
| Epoxy & Polyester Resins | Pre-warm the resin to 40-50°C to reduce viscosity before adding fumed silica. This improves wetting and reduces mixing time. |
| Solvent-Based Systems | Add fumed silica to the solvent first, then incorporate other components. This ensures maximum fumed silica-solvent interaction. |
Important: Do not use ball mills or three-roll mills for dispersing fumed silica — the mechanical forces can break down the primary particle agglomerates and reduce the effective surface area, diminishing rheological performance. High-speed dissolvers and rotor-stator mixers are the preferred dispersion methods.
Understanding the differences between fumed silica and precipitated silica is essential for selecting the right silica for your application. Both are synthetic amorphous silicon dioxide, but they differ fundamentally in production process, particle morphology, and performance characteristics.
| Property | Fumed Silica (Censil) | Precipitated Silica (Censil) |
|---|---|---|
| Production Process | Flame pyrolysis (gas phase) | Wet chemical precipitation |
| SiO₂ Purity | ≥99.9% | ≥98% (feed grade), ≥99% (food grade) |
| Primary Particle Size | 7-20 nm | 5-100 nm (aggregates) |
| BET Surface Area | 135-410 m²/g | 155-350 m²/g |
| Bulk Density | 30-50 g/L (very low) | 120-300 g/L |
| Particle Shape | Chain-like aggregates (branched) | Irregular / spherical (micropearl) |
| Primary Function | Rheology modifier, thickener, anti-settling | Reinforcement filler, carrier, anti-caking |
| Typical Dosage | 0.5-5% | 5-60 phr (parts per hundred rubber) |
| Price Range | Higher per kg, lower usage level | Lower per kg, higher usage level |
| Best For | Adhesives, sealants, coatings, composites, cosmetics | Rubber, feed, food, coatings (matting), tires |
Selection Rule: If you need rheology modification, thickening, anti-sag, or anti-settling at low dosage → choose fumed silica. If you need reinforcement, carrier, anti-caking, or bulk filling at higher dosage → choose precipitated silica. In some formulations (e.g., specialty coatings), both may be used together for complementary benefits.
Selecting the right fumed silica grade depends on your application requirements. The BET surface area is the primary selection criterion — higher surface area means stronger rheological effects but also higher viscosity build-up and more demanding dispersion requirements.
| Selection Factor | Low Surface Area (Censil 150) | Medium (Censil 200) | High (Censil 300) | Very High (Censil 380) |
|---|---|---|---|---|
| Thixotropic Strength | Moderate | Strong | Very strong | Maximum |
| Dispersion Difficulty | Easy | Moderate | More demanding | Most demanding |
| Transparency Impact | Lowest haze | Low haze | Moderate | Higher haze |
| Recommended For | Cosmetics, general-purpose, easy dispersion | Adhesives, sealants, FRP, coatings — most versatile | Construction sealants, composites, anti-sag | Specialty, maximum rheology needed |
Fumed silica (also known as gas phase silica) is an ultrafine synthetic amorphous silicon dioxide produced by flame pyrolysis of silicon tetrachloride in a hydrogen-oxygen flame. Fumed silica powder is used as a rheology modifier, thickener, anti-settling agent, and reinforcing filler across multiple industries: adhesives, sealants, coatings, composites (FRP/SMC/BMC), cosmetics, pharmaceuticals, and electronics encapsulation. Censil offers 4 grades with BET surface areas from 150 to 380 m²/g to cover the full range of fumed silica applications.
To properly disperse fumed silica, use a high-speed dissolver or rotor-stator mixer at 1,500-3,000 rpm tip speed (15-25 m/s). Add the fumed silica powder gradually into the liquid phase over 5-10 minutes, then continue high-shear mixing for 10-30 minutes until the batch is homogeneous and lump-free. For optimal thixotropic development, allow a rest period of 12-24 hours. Avoid ball mills and three-roll mills, which can damage the silica particle structure and reduce rheological effectiveness.
The key difference lies in the production process and particle morphology. Fumed silica is made by gas-phase flame pyrolysis, producing ultra-fine primary particles (7-20 nm) with chain-like aggregate structures, very high surface area (150-400 m²/g), and very low bulk density (30-50 g/L). Precipitated silica is made by wet chemical precipitation, with larger aggregates, moderate surface area (100-300 m²/g), and higher bulk density (120-300 g/L). Fumed silica is primarily a rheology modifier used at 0.5-5% dosage; precipitated silica is primarily a reinforcement filler and carrier used at 5-60 phr.
Yes. Censil 200 is designed as a direct alternative to Aerosil 200 with matching specifications: BET 200±25 m²/g, SiO₂ ≥99.9%, pH 3.5-4.5. It provides equivalent rheology modification and thickening in adhesives, sealants, coatings, and composite systems. Censil 200 also serves as a Cab-O-Sil M5 alternative and an HDK H20 alternative, offering 20-35% cost savings compared to imported brands. Many formulators have already made the switch without any reformulation needed.
Grade selection depends on the required rheological strength and dispersion tolerance: Censil 150 (BET ~150 m²/g) for easy dispersion, cosmetics, and low-haze applications; Censil 200 (BET ~200 m²/g) as the most versatile all-purpose grade for adhesives, sealants, FRP, and coatings; Censil 300 (BET ~300 m²/g) for high-performance construction sealants and composites requiring strong anti-sag; Censil 380 (BET ~380 m²/g) for maximum rheological effect in specialty applications.
Yes. Censil fumed silica is produced by Longyan Shenghe Chemical Co., Ltd. in Fujian, China. As a China-based fumed silica manufacturer, Censil offers factory-direct pricing with 20-35% cost savings versus imported brands. Standard packaging is 10 kg bags or 640 kg big bags. MOQ is 1 ton with 2-3 week lead time for standard grades. SENSIL International LLC (California, USA) handles international distribution and technical support.