One process, one exposure to temperature
Producing extrusion products particularly economically through the combination of a variety of process steps - this is direct extrusion. In the production, for example, of panels of wood flour/PP, acoustic and insulation films/panels/pipes using BaSO4 or even in the production of thermoforming films and biaxially oriented films, the intermediate step of pellet production is foregone as a result. At the end of the compounding process, shaping follows, during which the extrudate is processed into semi-finished products.
Areas of application
Why direct extrusion?
- More gentle processing: the product is only subjected to one heating and shearing step.
- More economical production: entire process steps are eliminated.
- Investment costs are significantly reduced since the pelletizing step is lost.
- Recipes can be converted and adjusted more flexibly.
- Up to 40% energy savings are possible.
From raw material to filmFilm extrusion
In recent years, Leistritz has equipped a great many systems for the production of thermoforming films with twin screw extruders. The reason for this is that increasing numbers of film producers in this field rely on the special vacuum technology which makes it possible to process bottle flakes directly without predrying. Up to 100% recycled material can thus be processed without adding any new material. Since most thermoforming films are used for food packaging, the films are furnished with cover layers by means of co-extrusion during the production process.
A well-rounded offerPipe extrusion
In this process, the melt is processed into pipes immediately after leaving the die in a direct extrusion procedure. The necessary ingredients, such as polymer, impact modifier, color pigments, chalk, etc., are supplied via split feed and the melt is homogenized in the extruder. Volatile components are drawn off from the process via a degassing module.
The melt travels via the melt pump to the screen changer, where it is continually filtered. The melt distributes itself in a circle around the die in the downstream pipe head. Pure polypropylene is processed in the overlapping co-extruder. The melt is applied to the pipe as an entirely fine and smooth outer layer film.