Color Contamination

What it is:

Color contamination, particularly when changing from dark to clear color, occurs when previous color is processed alongside the next processed polymer. It is especially critical to address this problem for change-overs to unpigmented (transparent) polymers.


In a thermoplastic processing environment, it can take a considerable amount of time to complete a color change or return material to virgin transparent polymer status. The rapidity of a color change can be influenced by pigment type, machine and process used, and polymer viscosity. Pigments impregnate the machine when processed for a long production run, and when injection molding machines are fitted with a hot-runner or a stack mold, color change could become extremely challenging due to the complexity of the tool itself. Any area where there is a lack of polymer flow can increase color contamination issues.


The use of a purging compound that is compatible with your polymer and viscosity will help you save time and energy when performing the color changing process.

A brand of Freudenberg.
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