Chemical Primer
Calcium based coagulants prepare fabric surfaces for digital pigment or reactive inkjet printing. Applying calcium nitrate pretreatment creates a localized reaction zone where ink droplets meet the treated fibre. The chemical causes the ink particles to crash out of suspension immediately upon contact.
Rapid stabilization prevents the pigment from migrating deep into the textile structure or spreading laterally. This localized effect is essential for maintaining the integrity of photographic details on woven substrates.
Coagulation Mechanism
Divalent calcium ions interact with the anionic groups present in the ink binder or the pigment dispersion. This calcium nitrate pretreatment destabilizes the charge that keeps the ink particles repelled from one another. Rapid flocculation results.
When the ink stays on the surface, the color yield remains high. Low penetration preserves the sharpness of the printed geometry.
Surface Application
Padding or spraying methods deliver the aqueous salt solution to the greige or bleached fabric before it enters the printer. A successful calcium nitrate pretreatment requires even distribution across the entire width of the material. Excess moisture must be removed through drying to avoid bleeding.
The concentration of the salt determines the degree of ink holdout achieved during the jetting stage. Precise control of the pickup percentage ensures that the subsequent ink layers bond correctly without cracking during the drying or curing phase.
Performance Boundary
Residual salts on the fabric may alter the hand feel if the concentration is too high. Proper washing after curing removes the salt to restore the original softness of the substrate.
