2. Application and dosage of liquid colorants

2.1 Principle

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...