High Shear Mixers Pigment dispersion for textiles

Wahal High shear mixers play a critical role in the pigment dispersion process in textile manufacture, primarily in the de-agglomeration stage. Here’s a breakdown of their function and importance:

1. Breaking Down Pigment Agglomerates:

• Raw pigments typically exist as clusters or agglomerates of primary particles held together by various forces.
• Wahal High shear mixers are designed to impart intense mechanical forces (shear forces) to the pigment slurry. This is achieved through:
  • High-speed rotation of impellers or rotors: These create turbulent flow and shear gradients within the liquid.
  • Close clearances between rotors and stators (in some designs): This forces the pigment suspension through a narrow gap at high velocity, subjecting the agglomerates to powerful shear stress.
• These forces effectively break down the large agglomerates into much smaller, ideally primary, pigment particles. This is crucial for achieving:
  • Maximum color strength: Smaller, well-dispersed particles offer a larger surface area for light interaction, leading to more vibrant and intense colors.
  • Uniform color: Consistent particle size ensures even light scattering and absorption across the fabric.
  • Improved fastness properties: Finer particles are better encapsulated by binders, leading to enhanced wash and rub fastness.

   

2. Enhancing Wetting:

• While the primary role is de-agglomeration, the intense mixing action in high shear mixers also aids in the wetting of the pigment particles by the liquid medium (usually water) and dispersing agents.
• Effective wetting is essential for the dispersing agents to properly adsorb onto the pigment surface and prevent re-agglomeration.