5. Pigment preparations

Colouring with pure pigments (dry colouring) is a delicate operation, often resulting in irregularities in shade, and always in dusting that is very dirty for the material and the environment. This is why plastics processors often use pigment preparations:

• Solid pigment preparations are called masterbatches;

• liquid pigment preparations are called liquid colorants.

Masterbatches are solid concentrates in the base polymer, which then acts as a binder or carrier. Liquid colorants are more or less viscous liquids in which the pigments are finely dispersed in concentrated form in a carrier compatible with most thermoplastics.