Coating dispersant classification – Metal soaps

Metal salts of advanced fatty acids, known as metal soap, such as barium stearate for a variety of plastics, the amount of 0.5% or so; zinc stearate for polyolefins, ABS, etc., the amount of 0.3%; calcium stearate for general-purpose plastics, external lubrication with a dosage of 0.2%-1.5%; other stearic soaps such as cadmium stearate, magnesium stearate, copper stearate.

The other case also constitutes controlled flocculation. The wetting and dispersing agent with one adsorption group and two or more secondary extended chain segments is restricted by the polarity of the dispersion medium. The extended segments of the wetting and dispersing agent are attracted to each other to form a double layer of adsorption of the auxiliary agent, and two pigment particles with the double layer of adsorption are connected by the polar group on the second layer of auxiliary agent to form a flocculation unit body, which adsorbs Most of the dispersants on the pigment particles connect the pigment particles through hydrogen bonding force or van der Waals force to form flocculation. However, this binding force is relatively weak and will be destroyed under high shear rates. The structure is sticky. Decrease, but when the shear rate disappears, the viscosity will be restored. It is this weak thixotropy that gives the coating many good properties.

Controlling flocculation makes up for the lack of steric hindrance caused by low molecular weight, honeywell pe wax and becomes an important factor for the stability of pigment dispersions.

Different types of wetting and dispersing agents have different degrees of interaction. This difference determines the effect of controlling flocculation. The magnitude of the interaction force is largely affected by the number of polar adsorption groups of the dispersant in the dispersion medium and the polarity of the dispersion medium. For example, the adsorption group is a highly polar substance, and the dispersion medium is non-polar, so it is more helpful for the interaction between these groups.