Dispersion Technology of Precipitated Silica in Coatings
The dispersion process of precipitated silica (silicon dioxide) in coatings involves three key stages:

**Crushing Stage:** Commercial-grade precipitated silica usually requires crushing and dispersion to achieve the fineness required for coatings. This process can be accomplished using equipment such as extruders, kneaders, three-roll mills, internal mixers, high-speed mixers, ball mills, and sand mills.

**Wetting Stage:** The interaction between the surface of the precipitated silica particles and the surrounding medium is a key factor in wetting. The wetting time is related to the porosity and geometric structure of the precipitated silica powder, increasing with increasing medium viscosity and decreasing with increasing wetting tension.

**Distribution Stage:** Uniform distribution is achieved by increasing the processing temperature and reducing the system viscosity, bringing the system into a turbulent state. In practice, low-molecular-weight additives (such as plasticizers or viscosity promoters) are often added to improve dispersibility.

Different viscosity coating systems require different dispersion equipment:
Low-viscosity coating systems: High-speed shear dispersers
High-viscosity silicone rubber systems: Kneaders or open mills
Powder systems: Three-dimensional high-speed dispersion or grinding dispersion
Thickening Mechanism of Precipitated Silica
Precipitated silica imparts excellent thickening effects to coatings through its unique microstructure:

**Three-dimensional network structure formation:** The surface of precipitated silica particles contains silanol groups, which can form hydrogen bonds with each other, building a loose three-dimensional network structure that increases the viscosity of the coating.

**Thixotropic behavior:** In architectural latex paints, adding an appropriate amount of precipitated silica allows the coating to maintain a stable state during storage. During application, the shear force breaks the network structure, reducing viscosity; after the shear force disappears, the structure quickly recovers, giving the coating thixotropic properties.

**Anti-settling and dispersion:** Precipitated silica adsorbs onto the surface of pigment and filler particles, changing their surface properties and increasing the repulsive force between the particles, effectively preventing the settling of pigments and fillers. Functional Characteristics: Precipitated silica has excellent dispersibility, thickening properties, and whitening capabilities, which can improve the strength, durability, and stain resistance of coatings.

High-Opacity Coating Formula Design
Precipitated silica plays a key role in developing high-opacity coating formulas:

Light Scattering Enhancement: The high specific surface area of precipitated silica allows light to undergo multiple reflections and scattering within the coating, significantly enhancing the coating's opacity.

Pigment-to-Binder Ratio Optimization: By adjusting the ratio of pigment to binder, opacity is ensured while controlling costs. In practical application, a dry film thickness of usually no more than 75 micrometers is sufficient to achieve complete coverage of visible light.

Near-Infrared Opacity: For reflective heat-insulating coatings, in addition to visible light coverage, the ability to block near-infrared radiation (which accounts for more than half of the total solar energy) must also be considered.

Formula Examples:
Master Paint Marigny Set: Achieves high opacity through a special formula, effectively hiding imperfections and color differences on old walls.
Carpoly Odorless High Opacity: Uses an additive-free formula with significant coverage effect, suitable for quick wall renovation.
Application Cases of Precipitated Silica in High-Opacity Coatings
Water-based Coating Applications: The high whiteness and fineness of precipitated silica increase the opacity and brightness of the coating, resulting in excellent optical effects.

PPG A400 Technology: Its unique pigment particle structure creates a uniform diffuse reflection effect, providing excellent coverage and a high-brightness surface.

Functional Coatings: In automotive metallic paints, precipitated silica ensures the uniform distribution of metallic pigments (such as aluminum powder), preventing agglomeration and sedimentation, and exhibiting a uniform and bright metallic luster.

Industrial Applications: Sanming Zhengyuan Chemical's precipitated silica products are widely used in thickeners, friction agents, and coating additives, with significant export growth.

Precipitated silica, through its unique dispersion and thickening properties, provides crucial technical support for the development of high-opacity coatings. By optimizing dispersion processes, controlling thickening mechanisms, and carefully designing formulations, precipitated silica can significantly improve the hiding power, application performance, and storage stability of coatings. In the future, with advancements in surface modification technology, the application of precipitated silica in the coatings field will become even more widespread and sophisticated.