Attacking black specks during colour and material changes in extrusion film processes.


Substantially reducing your scrap rate.

A customer’s extrusion line producing LDPE, LLDPE and PA film was facing severe problems with high scrap rates due to insufficient cleaning during material and colour transition leading to a high level of contamination in the head area as well as the screw. Black specks caused by carbonization lead to an unacceptably high scrap rate.

When they called us for help, our technical sales specialist closely collaborated with their production team on site. The objective was to speed up the cleaning process, reduce contamination and the reduce scrap rate. To find the best possible cleaning solution, the customer’s production parameters were at first simulated in our own laboratory before pilot testing started in the factory resulting in the definition of the best-performing combination of process parameters and purging compound.

We were able to achieve all our customer’s goals: The use of a purging compound specifically developed to be used with film extrusion lines made cleaning significantly faster and more efficient so that scrap rate could be reduced substantially. The Ultra Purge™ purging compound proved to be safe in use with the equipment as it is based on a chemical reaction technology.

Do you have similar challenges in your production process? Don’t hesitate to contact us. We are here to help you find the best solution to meet your objectives. A free sample for your specific application may be available.

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Are there differences between purge compounds for extrusion and injection moulding operations?

Yes. Purge compounds for extrusion are generally more viscous compared to polymers used in injection moulding. Purge compounds for injection moulding applications are generally designed to clean more fluid polymers. Purge compounds specially designed for the type of process they are intended to be used in will provide the best results.

Can purging compounds be used in hot runner systems, through screen packs, melt pumps and extrusion dies?

Not all purging compounds are safe for use in hot runner systems, screen packs, melt pumps and extrusion dies. However, there are some purging compounds that have been developed for such applications. A “mechanical” type purge compound can damage hot runner systems and other components. If you wish to also purge the hot runner, screen pack melt pump or extrusion die you should only use chemical reaction based purge compounds.

A brand of Freudenberg.
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