Residence time modeling of hot melt extrusion processes

Area of Science:

• Materials Science
• Chemical Engineering
• Process Engineering

Background:

• Hot melt extrusion (HME) is a key technique for mixing viscous melts.
• Material residence time significantly impacts final product properties in HME.

Purpose of the Study:

• To develop an experimental setup and mathematical model for evaluating residence time and distribution in twin screw extrusion.
• To characterize HME processes using derived parameters like dead time and mixing volume.

Main Methods:

• Modeling the extrusion process as a convolution of Gaussian and exponential functions.
• Introducing a tracer to measure concentration at the die and fitting to the residence time model.
• Performing a 2(3) design of experiments to assess the impact of feed rate, screw speed, and viscosity.

Main Results:

• An adequate correlation was found between experimental data and the developed residence time model.
• Key parameters such as dead time, apparent mixing volume, and axial mixing were derived.
• Powder feed rate, screw speed, and melt viscosity were identified as significant factors influencing residence time.

Conclusions:

• A validated residence time model provides insights into the hot melt extrusion process.
• The model aids in interpreting experimental data and understanding process dynamics.
• Controlling process parameters is essential for managing material residence time and product quality.