Using Dynisco’s ViscoIndicator to Control Polymer Additives in the Extrusion Process

Johannes Lorenz

04.08.2024

Today, many plastic processors are struggling with sustainability initiatives. More specifically, how they can support the desire or mandate to increase recycled material content without impacting quality.

The following case study will demonstrate how a company can affordably measure the polymer melt flow index (MFI)  and using the Dynisco ViscoIndicator can adjust the additive feeder to ensure each lb. (kg) of material meets the MFI desired MFI range along with providing a full lot certification to your quality department or in the recycler’s case the customer increasing the potential price per lb. (kg) because data showing the entire batch of material meets specification (not just a static datasheet) can be presented.

Application:  PP recycler who requires additives, in this case a peroxide, to be added to their material to adjust the MFI of their material to meet the specifications of their process.

The customer would like to define upper and lower control points for the Melt Flow Index of his recycled polymer.  If the material exceeds their targeted rate the Dynisco ViscoIndicator sends a 4-20 mA signal to the Dynisco ATC990 Controller which can retransmit the output into the output needed.  In this case the additive feeder uses a 0-10 Vdc signal to control the RPM of the additive feeder introducing the required amount of peroxide into the process, thus adjusting the polymer’s melt flow rate.  For this application, the Dynisco ViscoIndicator’ s signal works seamlessly with the additive feeder to create a feedback loop so only the required amount of additive is used ensuring the polymer meets the required specification.

This loop provides the “window into the process” today’s processors need to increase the percentage of recycled material with out sacrificing quality.  Setting recycling content based on MFI or IV allows the processor to maximize recycled content