Hydrophobic Precipitated Silica: A Versatile Functional Additive for Diverse Industrial Applications
Product Overview
Hydrophobic precipitated silica, a chemically modified inorganic material, is engineered through post-treatment processes that replace hydrophilic silanol groups (Si-OH) with organosilane groups (e.g., dimethyl or trimethyl silane) . This modification imparts exceptional water repellency, high dispersibility, and rheological control capabilities, making it indispensable across industries such as coatings, plastics, rubber, and specialty chemicals. With a typical particle size in the nanometer range and a BET surface area ranging from 100–300 m²/g, it combines the benefits of precipitated silica's cost-effectiveness with the performance advantages of hydrophobicity .
Key Applications & Benefits
**1.Anti-Blocking Agent for Latex and Plastic Films
Mechanism: Acts as a surface modifier by reducing inter-film adhesion through its microporous structure and low surface energy.
Advantages:
Prevents film layers from sticking during storage or transportation, ensuring smooth unwinding in PE/PP/PVC films .
Maintains film transparency (≥96% light transmittance) and mechanical strength while reducing friction coefficients (COF) by up to 50% .
Complies with FDA and EU RoHS standards, suitable for food-grade packaging .
**2.Anti-Settling & Thixotropic Agent in Paints/Inks
Role: Forms a 3D hydrogen-bonded network to prevent pigment sedimentation and improve sag resistance.
Performance Metrics:
Reduces settling by >90% in high-viscosity coatings (e.g., epoxy, polyurethane) .
Enhates brushability and leveling by balancing viscosity recovery (thixotropy index: 3.0–5.0) .
Optimizes dispersion stability in solvent-based systems, reducing wetting agent usage by 20–30% .
**3.Flow Aid in Fire Extinguishers and Powder Coatings
Functionality: Improves powder fluidity and prevents caking under humidity (RH >60%).
Certifications: Meets GA 578-2005 and ISO 14520-1 standards for dry powder fire suppressants .
Technical Data:
Particle size: D90 <40 μm for uniform sprayability.
Moisture absorption: <0.5% (24h, 25°C/75% RH) .
**4.Reinforcing Filler for Silicone Elastomers
Performance:
Increases tensile strength (up to 12 MPa) and tear resistance in LSR (liquid silicone rubber) .
Enables high loading (30–50 wt%) without compromising processability, ideal for automotive seals and medical devices .
Enhances thermal stability (service temperature: -50°C to +200°C) .
**5.Dielectric Modifier for Cable Insulation
Benefits:
Lowers dielectric constant (ε <2.8) and reduces energy loss in high-voltage cables .
Improves insulation resistance by >10^15 Ω·cm, meeting IEC 60243 standards .
**6.Anti-Abrasive Additive in Engineering Plastics
Applications:
Boosts scratch resistance (ASTM D1044: <5% haze increase after 1,000 cycles) in polyamide and PBT composites .
Enhances surface hardness (Rockwell M scale: +15%) while maintaining impact strength .
**7.Pharmaceutical & Food-Grade Anti-Caking Agent
Compliance:
USP/EP-grade purity (SiO₂ >99.9%, heavy metals <10 ppm) .
Effective moisture adsorption (up to 200% of self-weight) for powder flowability in APIs and food additives .