Olivier Catherine, Technical Director, Cloeren Incorporated April 2021
In this webinar, "Capillary Rheometry: Application to the Extrusion Process and Equipment Design", Olivier Catherine demonstrates the importance of rheology in extrusion process development and equipment design as part of his work at Cloeren Incorporated, a company that designs and manufactures Flat Film Extrusion Dies and Feedblocks.
1. Why Is Viscosity Important for Extrusion?
2. Shear Rheology
3. Measurement Techniques for Polymer Melts
4. Melt Flow Index
5. Rotational Rheometry / Dynamic Measurements
6. Viscoelastic Behavior of Extrusion Coating Resins
7. Transient Extensional Rheometry
8. Capillary Rheometry Principles and Measurements
- Rabinowitsch Correction
- Bagley Correction
- Historical Bagley
- Twin-Bore Rheometer
- Example of Corrected vs. Uncorrected Data
- Melt Fracture / Flow instability
- Melt Fracture / Flow instability -Application
- Thermal Stability
- Thermal Stability vs. Residence Time
9. PVB Film Extrusion Troubleshooting Example
- A real example of PVB film extrusion
- PVB Rheology
- Flow Simulation Conditions
- 3D Flow Simulation Results
- Flow Distribution Prediction
- Start-up Thickness Profiles
- Automatic Lip Adjustment
- Troubleshooting Methodology
- Melt Temperature Measurement
- Variable-Depth T/C
- Thermal Imaging
- Shear Rheology
- Comparison -Shear Flow
- New Flow Simulations
- New Flow Simulations -Velocity
- New Flow Simulations -Exit Velocity Profile
10. Conclusions
- Rheology and flow characterization of polymer melts is the foundation of extrusion equipment design.
- While capillary and rotational / oscillatory rheometers have both their own advantages, capillary rheometry can provide a wealth of relevant information.
- Extrusion dies are custom-designed: there is no generic design. The best flow performance can only be achieved with careful characterization of the flow behaviors.
- A combination of rheology and flow simulation is a powerful tool for design and process troubleshooting.
- Interpretation of data is as important as data accuracy.
- Understanding phenomena that can affect the viscosity data is critical:
*Flow instability
*Non-classic flow behaviors (rubbers, highly loaded materials)
*Thermal degradation
11. Thank you!