Mechanical Volumetric Dosing Calibration for Textile Pad Dyeing Systems
Mechanical volumetric dosing calibration requires gravimetric cross-verification and pressure-balanced manifolds to prevent shade tailing in pad dyeing.
Alginate Thickener Rheology
Flow Performance
Chemical structure of sodium alginate determines the flow limits of printing pastes during rotary screen application. In textile printing, alginate thickener rheology dictates how the dye paste moves under the squeegee and penetrates the fabric surface. The polymer chains of the thickener align under force to allow smooth passage through the screen mesh.
Shear Response
Viscosity drops sharply when high force is applied, which occurs during the passage of paste through the screen aperture. Under high shear, the thickener permits the dye to wet the fibre bundle quickly. This shear thinning behavior is a central trait of alginate thickener rheology in reactive printing.
When the force is removed, the paste recovers its structure rapidly to prevent spreading and maintain sharp print lines, avoiding run out of the design.
Viscosity Profile
Low shear viscosity maintains the shape of the printed design during drying. Lower viscosity paste causes dye to spread beyond the design boundary, resulting in blurred outlines.
Deformation Limit
High concentration of calcium ions in hard water causes gelation of the sodium alginate polymer. This reaction alters the flow characteristics, making the paste too stiff to pass through the screen. Using soft water ensures that alginate thickener rheology remains stable during the entire printing run.