How to quickly determine the dispersion performance of pigments?
16 Oct 2024
How to quickly determine the dispersion performance of pigments?
A variety of direct or indirect methods can be used to assess the dispersion of a pigment, the main ones being:
Fineness Plate Method
Hegman's Grinding Fineness Test Method (Hegman)
Overview: A quick and simple method for testing the fineness of grind of liquid systems.
Tool: Hegman's Fineness Plate with precision-machined shallow grooves on the surface, graduating from 100 microns to 0 microns.
Operation: Drop a small amount of grinding material into the deepest part of the groove and scrape evenly across to the end of the groove with a stainless steel double-edged spatula.
Judgment: Observe where the pigment particles first appear in dense concentrations, usually at least to scale 7 to be considered effectively dispersed.
Optical Microscope Method
Overview:Rapid and intuitive fineness testing method, can observe the pigment size, coloring power, particle morphology, size distribution and flocculation.
Operation: Drops of ground material on a slide, cover the coverslip with care to avoid over-dispersion of the material.
Disadvantage: The resolution is low, the minimum resolution is about 2 microns.
Electron Microscope Method
Overview: high resolution, can visualize the size of pigment particles, which has a decisive influence on the transparency, fluidity and color phase of the coating.
Advantages: high accuracy, can observe the finer pigment characteristics.
Disadvantages: Expensive equipment, long testing time, requires professional staff to analyze the data, and needs to wait until the sample is dry to measure.
Through the above methods, the dispersing performance of pigment can be judged quickly and accurately, which provides an important basis for quality control in coating and printing ink industries.