Colourants
Colourants are classified according to their chemical structure. A distinction is made between inorganic and organic colourants. Both groups, in turn, are broken down in terms of their origin according to natural and synthetic colour quality into white, coloured and black colourants. Special effect and luminescent colourants are also available.
Inorganic colourants are almost all pigments. Organic colourants are divided depending on their solubility in the relevant application medium into insoluble pigments or soluble dyes.
Pigments are colourants which are not soluble in the application medium. Their main applications are in dispersion paints, lacquers, plastics and printing inks. Because they are present in particle form, pigments provide better fastness properties than dyes.
Dyes are colourants which are soluble in the application medium. They are soluble in water or in organic solvents. The purpose for which the solvents are used plays a decisive role here. They are used in textile dyeing, in printer and inject inks. Dyes are also used for colouring paper and plastics.
By integrating pigments and dyes, individually tailored colour adjustments (for instance in accordance with RAL) can be carried out in technical plastics. In high-performance plastics, the selection of colourants is limited due to the high processing temperatures involved. Only colourants which are not subject to thermal degradation can be used at these temperatures. If special colour adjustments are required, a separate enquiry is required to determine the possibility of implementation.
Certain colour fluctuations cannot be excluded when dyeing plastics due to the intrinsic colour of the raw material (batch to batch variation between individual raw materials).
