Application and dosage of liquid colorants
Liquid colorants made of pigment dispersions

The liquid dispersion is fed directly into the screw feed groove of the injection molding machine or plastic extruder by means of a pump which meters the amount of colorant to be incorporated.

The pump can be peristaltic, diaphragm or piston.

The peristaltic pump (figure 2) is chosen by many manufacturers of liquid colorants for its versatility and cost-effectiveness. The principle behind peristaltic pumps was inspired by observation of how the intestines of the human body work; our intestines are equipped with peripheral muscles that enable matter to be moved by a succession of contractions and decontractions. The pump consists of a frame to which a motor is attached, the shaft...