Pigments for Coloration of Plastic

The product brand Colortherm® covers products with special properties that have been specifically developed for the plastics industry.

The use of colored plastics is growing in importance and the variety of possible fields of application for LANXESS pigments is rising continuously.

Applications range from all kinds of packaging materials, plastic tubes in the construction industry, cockpits, artificial leather in cars, plastic material in the electrical industry, artificial turf, tartan tracks on sports grounds and even wood plastics.

The pigments used for coloring plastics must satisfy a number of exacting technical requirements. Given the usually short dwell times and relatively low shear forces in the processing equipment, the pigments must have good dispersibility. The pigments must be easy to break down and distribute to reach their final tinting strength quickly. They must also have high thermal stability, and their lightfastness and weather stability must be adequate for the intended application. They should not migrate.

With the Colortherm® brand LANXESS offers a range of inorganic color pigments for the plastic industry which satisfy all of these requirements.

Colortherm® iron oxide pigments include Yellows, Reds, Browns and Blacks with a wide variety of additional shades in between.

Colortherm® pigments are easily dispersed in plastics. Some pigments are available in a micronized version with reduced agglomerates. The Colortherm® pigments are specially pre-tested in PVC to meet the high demands of coloring plastics.

Normal iron oxide yellow pigments possess limited heat stability. By inorganic aftertreatment Colortherm® Yellow 10 and Colortherm® Yellow 20 (the latter with hydrophobic properties), were developed. The heat stability of both pigments is up to 260 °C, therefore also suitable for HDPE and PS.

Colortherm® Yellow 30, a stabilized zinc ferrite, is stable up to 300 °C. It can be used in all engineering plastics, including ABS and PA.

Compared to the limited heat stability of normal yellows, the Colortherm® pigments can be used without restrictions. However, careful pre-testing should be carried out when by coloring PVC (when a good stabilization is required) or PP and ABS when performance demands are high.

Colortherm® Green pigments with their excellent resistance properties - heat stability, migration resistance, lightfastness and weather stability - are suitable for coloring almost any type of plastic. When dispersing these pigments, their relatively high inherent hardness should be borne in mind. This is particularly significant if high-speed mixers are used, e.g. when mixing PVC powders or working with a high-speed extruder, because the metal may be abraded more.

Colortherm® Green pigments can be mixed with brilliant yellow pigments which have good stability to produce the saturated greens required by, for example, the household appliance industry. Chromium Oxide Green pigments are also used in the technical sector, e.g. for the coloring of engineering plastics for machine components.

Colortherm® Green pigments contain nearly no chrome VI and can therefore be used for the coloration of food packaging.

The Global Competence Center Specialties will gladly provide advice with respect to specific applications or further product information.