Case Study: Ultra Purge™ in the Food Packaging Industry

The production of PET preforms is based on a multi-stage moulding process. The following example of a food packaging company illustrates the issues involved. How was the manufacturer able to identify and solve the problems associated with carbonisation and colour change – and why was the cooperation with Chem-Trend crucial? 

How to avoid black specks in PET preform production


A food packaging company was experiencing a series of challenges in their manufacturing process of PET preforms. Quality problems from carbonisation and colour change issues in the injection moulding process were not detected before shipment. Chem-Trend set out to find a solution – and finally managed to solve the problem in close collaboration with the customer.

Defective preforms result in customer complaints and batch rejections.

The main issue the food packaging company faced during the PET production process was: Defective preforms needed to be identified and discarded before they made their way into bottles. Chem-Trend analysed the situation with the customer and figured out that a significant obstacle to quality control was the packaging company’s short cycle times and high volume 24/7 production schedule limiting the chance for effective cleaning maintenance.

How Chem-Trend identified the problem

During a technical assessment, the team identified the machine’s extruder and shooting pot areas as the primary sources of material degradation and carbonisation, resulting in black specks. It focused on finding out a suitable time for maintenance to take place without hindering production. Subsequently, Chem-Trend’s technical experts determined a window for preventive purging during common mould and product change that helped the customer to resolve the common yet challenging issues of PET preform production.

PET with black specs
The solution: Ultra Purge™ purging compounds

To find a suitable solution to readjust the client’s PET performance manufacturing process, Chem-Trend recommended using the Ultra Purge™ purging compound technology during colour and tool change processes. The result quickly became apparent: All signs of contamination from carbon and black specks were removed in the subsequently produced preforms, leading to a dramatic improvement in product quality.

Results of using Chem-Trend’s Ultra Purge™ in a nutshell
  • 25% decrease in scrap alongside light colour change
  • 45% decrease in scrap alongside difficult colour change
  • 100% fewer rejected end products due to removal of black specks contamination

More information on the project is available here.


Read more from Chem-Trend here.

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