What Is Dispersion?
Dispersion is the breaking down of pigment agglomerates to their primary particle size and the uniform distribution of these particles throughout the polymer matrix. Good dispersion unlocks the pigment's full color yield.
Consequences of Inadequate Dispersion
- Speck formation on the film surface
- Reduced mechanical strength (notch effect)
- Variability in color tone and opacity
- Increased frequency of extruder filter changes
Critical Process Parameters
Dispersion quality is determined by screw configuration, temperature profile, screw speed, feed rate, and the chemical compatibility of the pigment–polymer interface. The high shear force of twin-screw extruders (TSE) provides an advantage in breaking down agglomerates.
Auxiliary Components
To improve dispersion efficiency, calcium stearate, waxes, and surfactants are widely used. These additives enhance the wettability of the pigment surface by the polymer.
Dispersion is the process that unlocks the pigment's true potential. Even the best pigment yields a mediocre final product when poorly dispersed.
Quality Control Methods
- Pressure filter value test
- Dispersion classification under the microscope
- Spectrophotometric color measurement on film samples
- Comparative tensile strength testing
Recommendation
Alba Pigment offers pigment references with low oil absorption and good wettable surface characteristics for masterbatch producers. Through sample-based trials and process consultancy, we can directly improve the quality of your final product.