Masterbatch

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The term masterbatch or color granulate is understood to mean plastic additives in the form of granules with a content of colorants or additives that are higher than in the end application. They are added to the natural plastic ( raw polymer ) for coloring or to change the properties. Masterbatches thereby increasing compared to powder shaped additives technical process reliability and are easy to process.

There are generally three groups of masterbatches . On the one hand, the color masterbatches, which are used to color plastic products, on the other hand, the additive masterbatches, which ensure certain properties of the end products, such as UV stabilization, flame protection , antistatic or antiblocking, as well as combination masterbatches that contain both dyes and Contains additives.

In the case of a masterbatch , an attempt is usually made to concentrate the additive as much as possible, i. H. to use as little polymer as possible to "glue" the additive together.

An explanation of how the term “ masterbatch ” might have come about may be based on a generalization of the rubber manufacturing process . In the past, only the master was allowed to produce highly concentrated and therefore expensive mixtures (= English batches ) for later dilution. It was the master's mixes (= masterbatches ). Color / additive / combination concentrates are the equivalent in German colloquial language. A more scientific but uncommon term would be “polymer-bound additives”.

Manufacturing

In the mixing shop, color pigments or chemicals are mixed with raw polymer (i.e. untreated plastic granulate ). This mixture is then melted in an extruder and then granulated .

Regardless of the production method, the masterbatch is then sent over a classifying sieve and possibly through a metal separator in order to remove plastic parts that are too large or too small or small metal parts that have become detached from the machine due to wear. Depending on the polymer carrier, the finished product is packed in plastic sacks or moisture-proof, aluminum-laminated containers and then delivered to plastics processing companies.

Alternatives

An alternative to masterbatch coloring is coloring with liquid colors or powder pigments.

literature

Individual evidence

  1. ↑ Bastian, Martin .: Coloring of plastics: product requirements - process engineering - test methodology . Hanser, Munich 2010, ISBN 3-446-41848-2 .