Dispersion of concentrated colour masterbatch into natural polymer carrier at letdown ratios of 1:20 to 1:100. Demands SX geometry due to extreme viscosity ratios.
Coefficient of Variation (CoV) ≤0.01 for colour uniformity (visual inspection will detect CoV >0.02). SX geometry with 18–24 elements for viscosity ratio >10,000:1. Thermal homogeneity also required — radial temperature gradient causes colour banding from viscosity variation.
Preferred MOC: 316SS or tool steel with hard chrome-plated bore. Removable element assembly essential for colour changeover.
Removable element assembly for rapid purge and colour changeover. Chrome-plated bore for polymer release and cleaning access. Thermal insulation of mixer housing to maintain uniform melt temperature. Element count determined by viscosity ratio calculation.