1. Product Overview Fumed silica is a functional nano-powder produced via the fumed process (high-temperature hydrolysis of silicon tetrachloride in an oxy-hydrogen flame). It can be surface-modified (hydrophobic type) or retain its inherent hydrophilic properties based on application requirements. The product strictly complies with industry standards, ISO 1248-2019 international specifications, and EU REACH regulatory requirements. Zhonglian Fumed Silica boasts core characteristics including ultra-high purity (≥99.8%), nano-scale primary particle size (7-40nm), and three-dimensional network-like aggregated structure (specific surface area: 50-400 m²/g). Among them, the hydrophilic type exhibits excellent hydrophilicity and dispersibility, while the hydrophobic type demonstrates outstanding hydrophobicity (water contact angle ≥120°, moisture absorption ≤0.5%). In adhesive, coating, and composite material systems, it provides core functions such as thickening, thixotropy enhancement, anti-settling, anti-sagging, reinforcement, and scratch resistance. Meanwhile, it features excellent chemical stability and is compatible with various production systems including solvent-based, solvent-free, and water-based systems, meeting the stringent requirements for performance consistency and reliability in mid-to-high-end products. 2. Technical Parameters Table Parameter Item Detailed Information Product Name Fumed Silica Appearance White fluffy nano-powder Primary Particle Size 7-40nm (can be precisely adjusted according to application scenarios) Silica Content ≥99.8% (dry basis) pH Value 3.8-5.5 (Hydrophilic Type); 5.0-7.0 (Hydrophobic Type) Loss on Drying ≤5% (105℃/2h, Hydrophilic Type); ≤0.5% (105℃/2h, Hydrophobic Type) Specific Surface Area 50-400m²/g (BET method) Surface Modifier Hydrophilic Type: None (inherent hydroxyl groups); Hydrophobic Type: Dimethyldichlorosilane, Hexamethyldisilazane, etc. (customizable modification type) Surface Property Hydrophilic Type: Water contact angle ≤30°, easily dispersible in aqueous systems; Hydrophobic Type: Water contact angle ≥120°, 24h static water absorption ≤0.3% Bulk Density 40-120g/L (low bulk density, easy to disperse and mix) Heavy Metal Content Lead ≤3mg/kg, Arsenic ≤1mg/kg, Cadmium ≤1mg/kg Dispersibility Hydrophilic Type: Stir at 2000r/min for 20min in aqueous system, dispersion uniformity ≥99.5%; Hydrophobic Type: Stir at 2000r/min for 20min in epoxy resin, dispersion uniformity ≥99.5% (no visible agglomeration) Thickening and Thixotropy Hydrophobic Type: Add 1.5% to polyurethane adhesive, viscosity increased by 300%-800%, Thixotropic Index (TI) ≥5.0; Hydrophilic Type: Add 1.0% to water-based coating, viscosity increased by 200%-500% Anti-settling Property Hydrophobic Type: Add 2% to solvent-based anti-corrosion coating, no obvious stratification after 48h, pigment sedimentation ≤0.5%; Hydrophilic Type: Add 1.2% to water-based latex paint, no obvious sedimentation after 72h Packaging 10kg valve bag Delivery Time Conventional models (including hydrophilic/standard hydrophobic): 5-10 days; Custom modified/high specific surface area models: 15-22 days Sample Free (≤100g, both hydrophilic and hydrophobic types available) Production Capacity Specialized production line for fumed silica: 6,000 tons/year (including hydrophilic and hydrophobic series) 3. Application Description Relying on its nanostructure and differentiated hydrophilic/hydrophobic modification advantages, Zhonglian Fumed Silica provides multi-dimensional performance improvement solutions for core production needs in adhesives, coatings, composite materials, food chemicals and other fields. The specific application values are as follows: 3.1 Adhesive Field •Hydrophobic Type: Add 1%-2% to epoxy resin to increase viscosity and prevent sagging, with shear strength improved by 20%-40%. After aging at 85℃/85%RH for 1000h, the strength retention rate is ≥85%. It can prevent moisture and bubbles in solvent-free polyurethane adhesives, suitable for high-precision scenarios such as new energy battery tab bonding. •Hydrophilic Type: Add 0.8%-1.5% to water-based adhesives to enhance system stability, prevent component stratification, and improve bonding strength by 15%-30%, suitable for water-based bonding scenarios such as packaging and woodworking. 3.2 Coating Field •Hydrophobic Type: Add 1.5%-3% to solvent-based industrial coatings, with no hard sediment after standing for 72h; Add 1.2%-2.0% to water-based wood coatings to improve water resistance (no wrinkling after boiling water immersion for 2h) and scratch resistance (HB pencil hardness → 2H), with transparency reduction ≤1.5%; Suitable for 3C casings in UV-curable coatings, withstanding 300℃ high temperature and maintaining thixotropic stability. •Hydrophilic Type: Add 1.0%-1.5% to water-based latex paint to prevent pigment sedimentation, improve leveling property, and increase scrub resistance to ≥2000 cycles; Add 0.5%-1.0% to water treatment agents to enhance flocculation effect and adsorption performance. 3.3 Multi-field Adaptability •Sealant: Add 2%-3% of hydrophobic type to improve tensile modulus and elastic recovery rate (≥90%) and resist thermal cycle aging; Hydrophilic type is suitable for water-based sealants to enhance adhesion. •Composite Material: Fills interface gaps; Hydrophobic type improves the damp-heat resistance of composite materials, with bending strength increased by 15%-25%; Hydrophilic type enhances compatibility with inorganic matrices. •Food Chemical Industry: Hydrophilic type meets food-grade standards and is used as anti-caking agent and thickener in powdered food and beverages; Hydrophobic type is used in cosmetics to improve water resistance (IPX6) and skin feel. 3.4 Multi-system Compatibility Hydrophilic type is compatible with aqueous and polar solvent systems, such as water-based coatings and food additives; Hydrophobic type is compatible with solvent-based and solvent-free systems, such as solvent-based coatings and high-temperature adhesives. Low specific surface area models (50-100 m²/g) are selected for automotive OEM coatings, with haze ≤3%; High specific surface area hydrophobic models (300-400 m²/g) are used for wind turbine blade adhesives, resisting -40℃ to 80℃ environment with significant thixotropic enhancement. 4. Factory Advantages •Customization Capability: Can customize surface properties (hydrophilic with retained hydroxyl groups/hydrophobic modifier type) and specific surface area parameters according to customer scenarios. For example, develop low activation energy hydrophobic models for low-temperature curing adhesives to maintain stable thixotropic performance at -10℃; Provide high-purity hydrophilic models for the food industry. •Advanced Production Technology: Adopt fully automatic closed-loop fumed production line with oxy-hydrogen flame temperature control accuracy of ±5℃ to ensure uniform primary particle size; Hydrophobic modification adopts fluidized bed continuous modification process with coating uniformity ≥98%, avoiding performance fluctuations caused by local hydrophilicity; Hydrophilic type adopts precise hydrolysis control to ensure stable hydroxyl content. •Rich Industry Application Experience: Provide customized products for domestic leading adhesive and coating enterprises as well as international chemical enterprises, suitable for 18+ subdivided fields such as new energy, automotive, electronics, building materials and food, exported to 30 countries and regions including Europe, North America and Southeast Asia. 5. Packaging and Transportation •Standard Packaging: 10kg valve bag, each bag is equipped with a one-way exhaust valve to isolate moisture and dust; Hydrophilic type is additionally equipped with a moisture-proof inner film. •Storage and Transportation Requirements: Store in a cool, dry and ventilated place (relative humidity ≤40%), avoid mixing with strong acids, strong alkalis and oxidants, shelf life is 15 months; It is a non-hazardous chemical, supporting sea transportation and international air transportation, and can provide air transportation identification report. •Label Specification: Each package shall be marked with product name, specifications (specific surface area, surface type/modifier), production batch number, shelf life, storage conditions and other information; English/multilingual labels are available for export orders.