Characteristics of Ceramic Ink Dispersants
Ceramic ink dispersants are specialized additives designed for ceramic inkjet printing processes. Their core function is to ensure uniform dispersion of ceramic pigments (e.g., metal oxides, inorganic colorants) in the ink system and maintain long-term stability. Since ceramic inks undergo high-temperature sintering (>1000°C) and require exceptional printing precision and color accuracy, dispersants must meet the following unique requirements:
1. High-Temperature Stability and Residue-Free Performance
Resistance to Thermal Decomposition: Dispersants must fully decompose or volatilize during sintering to avoid residual ash affecting ceramic surface quality (e.g., spots, reduced gloss).
Low-Ash Design: Prefer organosilicon-modified polymers or specific inorganic salt dispersants (e.g., phosphates) to ensure no residue after sintering.
2. High Dispersion Efficiency and Particle Stability
Nanoscale Dispersion Capability: Ceramic pigment particles must reach submicron or nanoscale sizes (<1 μm). Dispersants rely on strong adsorption (e.g., anchoring groups) and steric hindrance to prevent agglomeration.
Compatibility with High Solid Content: Ceramic inks typically have pigment concentrations of 30–50%. Dispersants must achieve efficient dispersion at low dosages to avoid excessive viscosity.
3. Strong Compatibility with Inorganic Pigments
Anchoring Group Design: Dispersant molecules require functional groups like phosphate (-PO₃H₂) or carboxylic acid (-COOH) to form strong chemical bonds with metal oxide surfaces (e.g., Al₂O₃, ZrO₂).
Electrolyte Resistance: Ceramic inks often contain inorganic salts (e.g., pH adjusters). Dispersants must remain stable in ionic environments to prevent salting-out and flocculation.
4. Printability and Rheology Control
Low Viscosity and High Fluidity: Dispersants must optimize ink rheology for precise droplet formation during printing (e.g., viscosity <20 mPa·s, surface tension 25–35 mN/m).
Shear-Thinning Behavior: Viscosity decreases under high shear (nozzle jetting) and recovers afterward to prevent sedimentation and nozzle clogging.
5. Environmental Compliance and Process Compatibility
Water-Based System Adaptability: Driven by eco-friendly trends, dispersants must be compatible with water-soluble resins and additives to avoid phase separation.
Hazard-Free Composition: Compliance with RoHS and REACH regulations, excluding APEOs, heavy metals, and other harmful substances.
6. Examples of Typical Dispersant Types
Phosphate Ester Dispersants
Anchor to ceramic particles via phosphate groups; heat-resistant; suitable for alumina/zirconia systems.
Example: Solsperse 41000 (Lubrizol).
Modified Polyacrylate Salts
Use electrostatic repulsion for aqueous systems but require nonionic co-additives to mitigate electrolyte sensitivity.
Silicone-Polyether Copolymers
Combine wettability and thermal decomposability; low ash content; ideal for high-end glaze inks.
Practical Challenges
Pigment Variability: Diverse surface properties of metal oxides (e.g., cobalt blue, chromium green) demand customized dispersants.
Sintering Color Consistency: Poor dispersion may cause localized color shifts, requiring optimization via particle size analysis (DLS) and Zeta potential monitoring.
Summary
The key characteristics of ceramic ink dispersants are high-temperature residue-free performance, nanoscale dispersion capability, strong anchoring adsorption, and precise rheology control. Their design must balance dispersion efficiency, printability, and post-sintering ceramic quality, making them critical additives for achieving high-resolution patterns and stable production in ceramic inkjet technology.
Anjeka has a ceramic ink dispersant, if you need to know more about it, please contact us.
