About Frank

Frank Knittel, a Senior Sales Engineer at ENTEX, oversees sales in the southern and western European markets. Additionally, he manages the Middle East region and global cable applications. A member of the ENTEX sales team for nearly three years, Knittel brings over 25 years of compounding experience, primarily with Co-Kneader technology. He holds a degree in mechanical engineering from the Karlsruhe Institute of Technology (KIT).

Can you briefly tell us the benefits of using a Planetary Roller Extruder (PRE)?

Due to increasingly complex formulations for products with customised properties, the demands on compounding processes are also becoming more complex. To realise such processes, compounding systems are required today that can meet high standards in terms of process reliability, efficiency and product quality.

For compounding processes, the PRE is characterised by its targeted mechanical adaptability and precise thermal process control.

The PRE offers some decisive advantages: It is the leading extrusion system for mixing processes and precise temperature control with the option of significant cooling. The excellent mixing properties are generated by a high degree of rolling and the large number of kneading gaps. The particularly efficient temperature control is achieved by the full-surface, liquid-based temperature control without hot spots and by the enormously large energy exchange surfaces of the cylinder- and central spindle walls.

The effective temperature control in combination with the low-shear material treatment also enables the processing of very sensitive formulation components. In addition, large quantities of solids and liquids of different viscosities can be processed without any problems. For foaming processes, the injection of gases and the feeding of blowing agents are possible in every zone of the process section.

With the help of active cooling, compounds can be cooled by 60 °C and more over one cylinder section in order to adjust the viscosity and the temperature of the extrudate, which is the prerequisite for efficient degassing and adding sensitive or reactive additives.

What are the biggest challenges within compounding?

For demanding compounding processes, it is important to feed recipe ingredients with very different physical properties and viscosities into corresponding temperature-controlled process zones at the right time and to mix and homogenise them over the shortest possible process distance without damaging the materials thermally or mechanically. The individually controllable feed and mixing behaviour of the PRE enables gentle compounding and excellent homogenisation.

The processing of materials in individual process zones with targeted temperatures and planned configuration of the kneading and damming elements also enables complex compounding processes. This variety of options for feeding different materials and the effective homogeneous mixing and precise tempering and active cooling characterises the PRE as a high-performance processing unit for a wide range of applications.

For consistently good product quality, efficient degassing is also important. Undesirable volatile substances can be effectively removed from extrudates with the PRE and reduced to a less than 1 ppm.

Could you tell us the various range of applications for PRE?

Today, the PRE covers the entire range of compounding, reaction and recycling technology including PVC.

Here are some examples for applications

• Plastics industry - e.g. for all PVC formulations, ABS, TPO, TPU, Prepreg compounds, bioplastics and any reactive formulations
• Recycling industry – e.g. waste tyre devulcanisation, film edge trim recycling as well as different depolymerization and other plastic recycling processes
• Chemical industry - e.g. for processes with endothermic and exothermic reactions, stripping and degassing processes
• Special applications - e.g. for Wood Plastic Composites (WPC), drying processes, cooling processes
• Rubber and elastomer industry - e.g. for tyres, seals, roofing membranes, conveyor belts
• Adhesives industry - e.g. for Hotmelt, PSA, SMP and solvent free adhesives, and more...

What can visitors expect to learn from your presentation?

During the presentation, the mechanical structure and the various functionalities and unique selling points of the PRE will be clearly illustrated. The special working principle and the mechanical configuration options of this modular extruder system will be explained, particularly with regard to compounding processes.

The special features and mode of operation as well as the advantages of liquid-based temperature control are also explained. Furthermore, the very efficient degassing system and how it can be used effectively for compounding processes will be described. Finally, the technical, economic and ecological advantages will be summarised to give the audience a comprehensive impression of the PRE's performance and customer benefits. 

Visit us at our stand C828.

Frank Knittel will be speaking on Day 2 at the Compounding World Expo Theatre.