Basic Requirements for Transparent Thickeners in High-Gloss Inks
As a special functional ink, high-gloss inks have strict requirements for transparent thickeners:

Transparency Maintenance: The thickener must not affect the transparency and gloss of the ink.
Rheological Properties: Good thixotropy and leveling properties are required to ensure uniform printing results.
Stability: Compatible with the ink system, it should not settle or separate during long-term storage.

Film-Forming Properties: It should be able to form a smooth, high-gloss film. Chemical Inertness: Does not affect the performance of other components in the ink.

Characteristics of Fumed Silica: Fumed silica (fumed silicon dioxide) is a nanoscale inorganic material with the following characteristics:
Particle Size: Primary particle size 7-40nm, specific surface area 100-400m²/g
Purity: SiO₂ content ≥99.8%, high chemical purity
Structure: Porous, strong surface adsorption, capable of forming a three-dimensional network structure
Physical Properties: White, fluffy powder, non-toxic, odorless, and heat-resistant. (Melting point 1610℃)
Optical properties: Refractive index 1.457, similar to resin coatings

Specific advantages of fumed silica in high-gloss inks
Excellent transparency retention: Nanoscale particle size (10-20nm) is much smaller than the wavelength of visible light, causing no light scattering.
Refractive index matches the resin substrate, ensuring ink transparency.

Highly efficient thickening ability: High specific surface area (145-300m²/g) provides strong adsorption capacity. Low addition amount (typically 0.1-0.5%) Ideal viscosity can be achieved.

Ideal rheological properties: Thixotropy prevents sagging and splattering during printing. Viscosity decreases during application and recovers to high viscosity after printing, ensuring clear patterns.

Chemical stability: Chemically inert and does not react with other ink components. High temperature and aging resistance, extending ink shelf life.

Gloss enhancement effect: Nanoparticles fill microscopic defects in the film layer, forming a smooth surface. Improves the specular reflection effect of the ink film.

Comparative advantages with other thickeners: Characteristics Fumed silica, polyurethane thickener, cellulose thickener
Transparency: Excellent (nanoscale), Average, Poor
Thickening efficiency: High (large specific surface area), Medium, Low
Thixotropy: Excellent, Good, Average
Chemical stability: Excellent, Good, Average
High temperature resistance: Excellent (melting point 1610℃), Average, Poor

Dosage: 0.1-0.5%, 0.5-2%, 1-3%
Cost: High, Medium, Low
Application Recommendations
Dosage: The recommended initial dosage is 0.2-0.3%, adjusted according to actual results.
Dispersion process: High-speed dispersion is required to ensure sufficient dispersion and avoid agglomeration.
Model selection: Hydrophilic fumed silica (such as A200, N20, etc.) is recommended.
Compatibility testing: Compatibility testing with specific ink systems is required.

Fuel silica, with its unique nanoscale properties and excellent performance, has become an ideal choice for transparent thickeners in high-gloss inks, especially suitable for applications requiring high transparency, gloss, and stability.