Bandera revisited extrusion coating technology for rigid films

Over ten years ago Bandera developed several plants for rigid film extrusion with integrated extrusion coating for a large European customer. This was a challenge, both from equipment design view and from that of the line performances required by the customer.

This served as a basis for supplies of similar technologies to other large producers. Existing renowned Bandera customers, already happy with the supplied standard equipment, kept confidence in the company when it faced challenges of increased complexity.

Bandera has always had the spirit of experimenting, together with the customer. This way of working helped refining the technology to various requirements and paving the way in innovative sectors.

Recently, a top international player, Bandera customer for both standard and specialized extrusion equipment, has been seeking for a turnkey, high-performance multi-layer PET extrusion line for rigid film & sheet for thermoformed packaging. Naturally, they reached Bandera once again for the project.

The developed customized line has a dedicated extrusion coating section, allowing for barrier film production and direct application onto freshly extruded PET sheet. Planned outputs are of the order of 2000 kg/h. The line comprises a total of 9 extruders:

– Three for PET sheet production, including one patented co-rotating twin screw extruder for processing PET regrind. This extruder is fit with a volumetric melt pump and a superfiltration screen changer, allowing for increased raw material purification. The other two single-screw co-extruders make external layers from virgin material.

– Six smaller extruders for barrier film, vital to the tailored line. These come fit with material handling/conveying and gravimetric dosing systems, manual screen-changers, automatic single-manifold flat extrusion die, chill roll unit, haul-off silicone coating/drying device and an alternative oxy-dry unit.

Otherwise, main line equipment includes:

• Cooling/polishing calender roll stack equipped with cross-axis system for ultrathin sheet processing and with in-line barrier film lamination unit
• Thickness control system
• Semi-automatic cantilever winding system. Up to three reels can be wound on a single shaft.

The project demonstrates once again that Bandera's commitment to excellence and innovation leads to more future successes.