Coating Application
Industrial finishing equipment applies a precise layer of chemical primers to the fabric surface before digital printing occurs. This pre-treatment padding involves passing the textile through a trough of liquid and then through a set of squeeze rollers.
Fluid Retention
Rollers apply consistent pressure to force the solution into the structure of the yarn while removing excess liquid. The percentage of weight gain, known as the wet pick up, is monitored to verify uniform coating across the entire roll. Correct pressure settings are necessary to achieving a repeatable finish on different fabric constructions.
Ink Fixation
Primers usually contain thickening agents and chemicals that keep the ink droplets on the surface of the fabric. Without pre-treatment padding, the low viscosity inks used in digital machines would wick along the fibres, resulting in blurry edges and poor colour yield. Specific formulations are chosen based on whether the final print uses reactive or pigment dyes.
The chemical composition must also neutralize any residual oils or waxes from the weaving process that might repel the ink.
Drying Stage
Fabric must be dried to a specific moisture level before it can be loaded onto the printer. Over-drying can make the fabric brittle or affect the chemical reactivity of the coating. Careful temperature control during this phase prevents yellowing of white grounds or migration of the pre-treatment chemicals.
