Water based digital inkjet dispersants require the selection of polymer block/comb dispersants (anionic/nonionic),
mainly depending on the type, particle size, and system viscosity of the dispersed pigment, its nozzle compatibility,
storage stability, and environmental requirements.
I、 Firstly, clarify the core requirements for digital inkjet dispersants
1. To disperse the pigment ultrafine, the particle size should be controlled at 50-200 nm to prevent clogging of the
nozzle and improve the clarity of the ink system.
2. The viscosity of the ink system should be low, and low foam is unstable. It is necessary to adapt to piezoelectric/
thermal foaming nozzles to ensure smooth spraying without satellite spots.
3. The storage stability of the ink system should be high, with a stable pH value of 7-9, able to withstand certain
temperature storage, and long-term non stratification/flocculation.
4. The ink system requires low VOC and APEO free: it meets environmental requirements and does not affect the
film formation and water resistance of the system after film formation.
II、 Select dispersant based on pigment type
1. Inorganic pigments (titanium dioxide, iron oxide), choose anionic polymer dispersants (strong anchoring,
electrostatic stability).
-Recommended dispersants: HR-4039AB, HR-4010.
-Dosage: 0.5-5% (for pigments).
2. Organic pigments (phthalocyanine, azo), selected block copolymers (non-ionic/anionic), have steric hindrance
and electrostatic bistability effects.
-Recommended dispersants: HR-4039AC, HR-4059.
-Dosage: 10-35% (for pigments).
3. For difficult to disperse carbon black, choose a high anchoring and high hydrophobic segment specific dispersant.
-Recommended dispersants: HR-4057, HR-4059.
-Dosage: 25-60% (for pigments).
III、 Select dispersant based on chemical type
1. Anionic dispersant, advantages: dispersant has strong viscosity reduction for pigments, high storage stability,
and moderate cost.
Disadvantages: It is highly sensitive to pH values (7-9 is optimal) and conflicts with cationic additives.
2. Non ionic dispersant, advantages: high pH tolerance (6-10), good product compatibility, and low foaming.
Disadvantages: Weak viscosity reduction of pigments, large dosage, and slightly poor water resistance.
3. Polymer block dispersant (high-end preferred), advantages: strong anchoring, double-layer stability (electrostatic+
steric hindrance), small particle size, and good long-term storage stability.
Disadvantage: The price is relatively high.
IV、 Key performance indicators required for testing
1. Pigment particle size distribution: D50<150 nm, narrow distribution (PDI<0.2).
2. System viscosity requirement: 5-20 mPa · s (25 ℃), to be compatible with the nozzle.
3. Zeta potential of particles: -30~-50 mV, strong electrostatic stability.
4. Thermal storage stability of the system: After 7 days of thermal storage at 50 ℃, no flocculation or particle size
growth of less than 10% will occur.
5. Surface tension of the system: 25-35 mN/m, spray formed.
V、 Recommended mature solutions for digital inkjet printing
HR-4058, HR-4057, HR-4039AC, HR-4059 dispersant (inkjet specific).
VI、 Quick Handsome Selection Process
1. Determine the type of pigment (inorganic/organic/carbon black).
2. Prioritize the use of polymer block anionic dispersants.
3. Determine the addition ratio based on the amount of pigment used (1-5% inorganic, 10-30% organic).
4. Strictly test the particle size, viscosity, and stability of the system before adjusting the dosage.
