Clextral designs, manufactures, installs and maintains custom-made lines for plastic extrusion to produce technical compounds for the plastics industry. Our co-rotating twin-screw plastic extrusion technology and our long experience in product development ensure the efficiency of this highly flexible and scalable process.
The compounding of polymers, often made with mineral powder-based fillers, can also be achieved with integrated vegetable fibers. In these processes, fibers are continuously introduced into the polymer after it has been melted. Clextral has been working for several years on economical and ecological alternatives to conventional polymers derived from oil (ou petroleum-based polymers).
What are the components of a twin-screw plastic extrusion line?
Each production line for extruded plastic is specific, corresponding to the requirements for processing specialty compounds, biodegradable composites or recycled plastics.
A standard line generally begins with pneumatic transport of raw materials from silos or big bags to surge hoppers located after the volumetric or weighing feeders. A side feeder for loads or fibers feeding can also be used on the twin-screw extruder. On the sleeves, atmospheric or vacuum degassing devices allow to remove moisture or monomer residuals. The twin-screw co-rotating plastic extruder melts the polymer, adding fillers and/or fibers to perform thorough mixing of the materials. After degassing and the extrusion process itself, the material is transferred to an area for the final granulation stage. Different cutting systems can be used, such as sectional reeds, underwater ring shearing or underwater cutting.
Versatile lines for high quality compounds
Clextral twin-screw plastic extrusion lines provide significant advantages in the treatment of compounds for the extruded plastic industry:
- Exceptional versatility for continuous processing within a single machine that mixes (micro and macro mixing), kneads, melts, degasses and shapes materials.
- Continuous treatment of reactions, mixing and kneading
- Dedicated screw profiles, ensuring quality mixing and proper dissemination of pigments
- Control of product fusion, cooling, shaping and degassing
- Capacity to premix pigments and polymers, fed by metering systems upstream or injected at later stages of the process
- Quality and flexibility, with the possibility of using a wide range of raw materials processed appropriately, enabling the manufacturing of compounds with varying viscosity densities and other features
- Productivity and cleanliness:
- Short residence time to protect temperature-sensitive materials
- High levels of mechanical torque for increased productivity
- Easy access to screws to reduce changeover time by simplifying product configuration changes, with sleeve openings that allow immediate access for clean and reconfiguring screws
- Screw elements with surfaces that have been carefully rectified to enhance the metal/metal interface, to prevent material getting caught between screw sections
Clextral also offers its expertise and dedicated equipment to plastic industry manufacturers at its test center to try out new compounds and improve manufacturing processes. Design of new compounds, prototyping, testing and pre-industrial ramp-ups can all be carried out independently and confidentially at our facilities with the participation of our experts.