Colloidal Silicon Dioxide

Product Details

CasNo： 7631-86-9

MF： SiO2

Appearance： powder

Delivery Time： 15 days

Packing： 25kg/bag

Purity： 99%

• Basic Information
  • Molecular Formula: SiO2​
  • CAS Number: 7631 - 86 - 9
  • Appearance: White powder
  • Melting Point: 1750℃
• Product Classificationwacker.com
  • Hydrophilic Fumed Silica: It is produced by the hydrolysis of volatile chlorosilanes in an oxy - hydrogen flame. In terms of chemical composition, it is composed of high - purity amorphous silica, showing a loose white powder shape, and can be dispersed in water.
  • Hydrophobic Fumed Silica: It is chemically modified from hydrophilic fumed silica with silanes, silazanes or siloxanes. It has hydrophobicity and cannot be dispersed in water, and is especially suitable as a rheological aid for polar polymer matrix systems.
• Physical and Chemical Properties
  • Particle Size: The primary particle size is about 7 - 40nm, and the aggregate particle size is about 200 - 500nm.
  • Specific Surface Area: Relatively large, 100 - 400m²/g.
  • Bulk Density: Relatively small, about 50g/L.
• Performance Characteristics
  • Thickening and Thixotropic Properties: As a thixotropic agent and thickening agent for liquids, it can prevent sedimentation and sagging, and effectively solve the problems of coating application and storage.
  • Good Dispersibility: It can improve the suspension and dispersibility of pigments and fillers in liquid systems, and is used as a dispersing and grinding aid.
  • Corrosion Resistance Improvement: It can improve the corrosion resistance, water resistance, scratch resistance, etc. of the coating, and can also enhance the physical and mechanical properties, adhesion and flexibility of the paint film.
  • Reinforcement Effect: When added to rubber and other materials, it can improve the visco - elastic properties of rubber and elastomers, playing a reinforcement role.
• Production Method: Usually, the chemical vapor deposition method is adopted, also known as the pyrolysis method, dry method or combustion method. The raw materials are generally silicon tetrachloride, oxygen and hydrogen, which react at high temperature to produce fumed silica. The reaction formula is SiCl4​+2H2​+O2​→SiO2​+4HCl. The generated fumed silica is processed through aggregation, separation, de - acidification and other steps to obtain the finished product.
• Application Fields
  • Rubber and Plastic: When added to rubber or plastic, it can enhance tear resistance, wear resistance and mechanical strength.
  • Coatings and Inks: As a thixotropic agent, it can prevent sagging, improve the uniformity of the coating and anti - sedimentation, and can also improve the rheological properties and stability of inks.
  • Adhesives and Sealants: It can enhance the bonding strength, adjust the fluidity, and prevent flowing before curing.
  • Pharmaceutical Field: It is used as a flow aid, excipient and carrier, which can solve the problems of poor fluidity of particles and powders in drug production, and is also helpful for drug disintegration and sustained - release.
  • Cosmetics Field: It is used in sunscreens, foundations, etc. It can be used as a thickening agent, and can also make the pigment evenly distributed and prevent pigment sedimentation.
• Packaging and Storage: Generally, it is packaged in a sealed manner and stored in a cool, dry and ventilated place, away from incompatible substances such as oxidants.