Purge Compounds for Competitive Advantage in Thermoplastic Processing

Thermoplastic processors understand that their operational efficiency and bottom line are negatively affected by machine down-time and scrap associated with color or polymer changes. They also see the negative effects on quality by black spots in their finished products due to carbonization of their screw and barrel assemblies. However, many thermoplastic processors do not understand the significant operational advantages of using specialized, high performance, chemically based purging compounds to address these issues.

Purge compounds are extremely important for modern thermoplastic processors and the use of purging compounds that are designed specifically for operational process and parameters can provide a significant competitive advantage. Eliminating carbon buildup in screw and barrel assemblies, as well as on die sets and tooling, has a significant impact on processing efficiency, scrap rates, tool & die life and equipment maintenance. Reductions in color or polymer change-over times can significantly enhance operational margins by increasing equipment and labor uptime, allowing organizational assets to be more fully leveraged toward providing complete value to the manufacturing process.

Chem-Trend’s Lusin® brand of purge compounds covers a wide array of process applications, polymers, operating temperatures and equipment types. They have been specifically developed to address the challenges faced by thermoplastic processors and add significant value to their operations. We even offer multiple versions that are NSF registered.

We encourage you to contact us and learn first-hand what our high performance purging compounds can do to improve your operation. Or, find out more about our solutions to thermoplastic processing challenges in the expanded sections below.

Specialized Purging Compounds Designed for Specific Polymers

Chem-Trend is a company that is known around the world for its highly advanced release agents and we have leveraged our capabilities to develop state-of-the-art purging compounds. Our long heritage in creating innovative solutions for releasing molded products from metal surfaces has been applied to the releasing of colorants and carbon contaminants from extrusion equipment. We have used our knowledge and expertise to develop Lusin® purging compounds specifically for addressing the particular raw material required to be purged. In general, all polymers we address can be placed into three main categories:

  • Polyolefins (e.g. PP, PE, TPO)
  • High temperature resins (e.g. PEEK, PSU, etc.)
  • Engineered resins (e.g. ABS, HIPS, PS, PA, etc.)

Each type of polymer has different characteristics and properties which result in different purging challenges. Chem-Trend has spent significant time studying these challenges by working directly with thermoplastic processors on their production floors. We then develop, test and refine our products to overcome those challenges. At Chem-Trend we do not believe that a “one-size fits all” approach provides the best result; therefore, we offer a wide range of purging compounds to provide the best solutions to your processing challenges, including the challenge of utilizing NSF registered products.

Call us, send in a contact form or continue your research by reading our Purging Compound Products brochure and frequently asked questions about purging compounds to learn more about how our high performance purging compounds can benefit your operation.

Advantages of Lusin® Purging Compounds

Many purging compounds are mechanical-action based formulations (scrubbing/scraping), which are abrasive and can damage the screw and barrel over time and will damage mold surfaces. Lusin® purging compounds are chemical-action based and significantly different from both mechanical action formulations, as well as other chemical based competitive purge compounds. Because of Chem-Trend’s 50-plus years of experience in developing some of the world’s most advanced release agents we have been able to use the principles of releasing molded products from metal surfaces to the releasing of colorants and carbon contaminants from extrusion equipment. We have also done it safely, so that our purge compounds can be run not only through the screw and barrel assembly, but also through the downstream equipment (eg. Hot Runner Systems), where most contamination settles, thereby removing contamination throughout the process.

Our Lusin® purge compound technology actually deep cleans your system. The images below show a run of parts that were made with a competitor’s purging compound (on the left), compared with a run of parts from the same machine using a Lusin® purge compound run immediately after a purge was completed with a competitor’s product (on the right). Although the competitor’s product appeared to clean the machine, Chem-Trend’s purge compound still removed a significant amount of contamination. This is the difference between the machine appearing to be clean and it actually being clean.

Competitor's purge compound Chem-Trend purge compound after competitor's

Purge completed with competitor’s product.

Purge completed with Lusin® immediately after purge with competitor’s product.

Chem-Trend’s Lusin® purging compounds are different:

  • our focus is on working at the molecular level to release contaminants from their bond with metal parts, not on conventional chemistry or mechanical scrubbing,
  • our purge compounds are safe to use throughout the entire machine, not just the barrel and screw,
  • you don’t have to change your process or your machine settings to run our purging compounds; they run within your established parameters of production;
  • you don’t have to increase the amount of purge compound used each time because our product cleans the machine thoroughly rather than competitive products that become increasingly ineffective over time because they leave carbon contaminants behind.

To learn more about how our high performance purging compounds can benefit your operation call us, send in a contact form, or explore the additional information below.

Benefits of Using Purging Compounds for Preventative Maintenance

The majority of thermoplastic processors who utilize purging compounds typically use them for color / material changes when:

  • transitioning from a dark color to a lighter color;
  • start-up production has flow marks or swirls from the previous material / color;
  • changing material with high temperature differences and / or melt flow.

In these instances the purging compound is most notably in effect in the Feeding Zone and Melting Zone as illustrated below.

Areas of thermoplastic processing auger affected by purge compounds

However, Lusin® purging compounds should also be used for shut-down or upon start-up to help remove black spots and burnt materials caused by:

  • processing a heat sensitive material at the wrong setting,
  • processing different temperature polymers,
  • a damaged / worn screw that has a dead zone area where material does not move through.

In these instances the purging compound is most notably in effect in the Metering Zone of the screw system illustrated above and is addressing the heavy areas of carbon and color buildup. Penetrating the layer of contaminants and releasing them is a key element of Lusin® purge technology.

In some applications where quality requirements are very high and the formation of burnt material is a typical problem, such as processing PMMA or Polycarbonate materials for transparent applications, we recommend utilizing Lusin® purge compounds as part of a preventive maintenance process, in addition to utilizing them at the time of color or material change-over.

Starting from a clean screw, barrel and hot runner, Lusin® purging compounds should be used before regular production begins, ensuring that the quality of produced parts are within QC requirements. By using Lusin® purge compounds regularly, the buildup of carbon will be limited, keeping production running more smoothly, reducing scrap and extending equipment life.

To take advantage of our expertise in improving operational efficiency, reducing scrap and lowering thermoplastic processing operational costs, contact us today.

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Case Study:

  • Color Change Challenges

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  • FAQs: Purging Compounds

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    Learn more about purging compounds for thermoplastics applications and get answers to frequently asked questions.

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