Flow Behavior
Rheological analysis determines the velocity gradient within a moving liquid during coating or finishing operations. In textile finishing plants, fluid shear rate dictates the performance of thickeners and binders used in pigment printing pastes. This parameter measures the speed at which adjacent layers of the fluid move relative to each other under applied force.
It influences how the paste flows through the screen mesh and onto the fabric.
Processing Factor
Industrial printing machinery subjects finishing chemicals to extreme mechanical stress as they pass through narrow gaps. Changing the fluid shear rate alters the viscosity of non-Newtonian formulations, affecting penetration into the yarn core. If the rate is too high, the paste may thin excessively and bleed beyond the pattern boundaries.
Viscosity Adjustment
Starch solutions and synthetic polymers exhibit shear-thinning behavior to facilitate smooth transfer onto moving fabric webs. Measuring fluid shear rate allows engineers to formulate finishing chemical mixtures that resist dripping at rest but flow readily under the squeegee. This control ensures uniform application across the fabric width.
Application Boundary
Roller coating systems require stable shear performance to prevent surface defects in waterproof fabric layers. Under high fluid shear rate conditions, unstable emulsions can break and cause uneven polymer deposition.
