Dosage of dispersant

Choosing the most suitable dispersant is often difficult, and their dosage also requires special guidance.

1. The choice of dispersant is also related to the surface characteristics of the pigment.

The polarity of pigment surfaces also varies from organic pigments (non-polar) to inorganic pigments (polar), which means that the choice of anchoring groups for dispersants is also important for optimal adsorption. Choosing anionic anchoring groups is better for inorganic pigments, while choosing cationic anchoring groups is more suitable for organic pigments.

2. The surface area of the pigment also determines the amount of dispersant used.

Overall, if the dosage is too small, the optimal effect cannot be achieved. If too much is used, the thickness of the spatial hindrance will decrease due to overcrowding, and the optimal effect will not be achieved. Typically, the optimal dosage range is 2-2.5mg of polymer dispersant per square meter of pigment surface area.

A ladder like evaluation should be conducted around the polymer dosage level of 2-2.5mg/m2. The measurement of paste viscosity can provide a basis for selecting the lowest value of the optimal dosage, although it can also display the maximum value of an optimal dosage by measuring gloss or color intensity. For example, if the surface area of phthalocyanine blue pigment is 50 m2/g, a typical dosage is: phthalocyanine blue pigment 30.0 (i.e. 10% active dispersant to pigment weight) polymer dispersant: 3.0.