Integrated coating for multilayer sheets

More than a decade ago, Bandera supplied a couple of rigid film extrusion lines with integrated extrusion-coating systems to an important European processor. This represented a challenge, since equipment design and manufacturing were customized and subsequent experimentation was carried out to attain the line performances expected by the customer for his specific application. This experience was an enrichment and laid the basis for future supply of such type of technology to other important producers, i.e.: previously well-established Bandera customers for standard extrusion equipment, who were fully confident to have Bandera walk aside them even when facing their more complex new endeavours.

Throughout these years, Bandera has continued to experiment, in cooperation with its customers, to refine this technology for new performances, to make it suitable to fulfil different requirements, gaining ground in innovative fields.

An important international processor, again a well-established Bandera customer for both standard and specialized extrusion equipment, with wide concerns in the market, recently decided to renew their fellowship with Bandera. This customer awarded Bandera an order for the supply of a turnkey, high-tech multilayer PET rigid film/sheet extrusion line for the production of thermoformed packaging products. The line integrates an extrusion coating section for the production of barrier film for direct application to extruded PET sheet.

This out-of-standard line, foreseen for an output of 2,000 kg/h, installs nine extruders:

- three extruders for PET sheet production, one of which a corotating twin screw extruder, Bandera patented, fit to process PET regrind, equipped with volumetric melt pump and superfiltration screen changer, for higher purification; two single-screw coextruders for the outer virgin material skin layers;

- six smaller-size extruders, for barrier film production, representing the core of this hi-tech line, i.e: the extrusion coating section. These extruders are equipped with raw material handling/ conveying and gravimetric dosing systems, manual screen-changers, automatic single manifold flat extrusion die, chill roll group, haul-off silicone coating and drying device and an alternative oxy-dry group.

The line also includes the following main equipment: automatic flat extrusion die; cooling and polishing calender roll stack, with cross axis system to process even ultrathin sheets, equipped with inline barrier film lamination system; thickness control system; semi-automatic cantilever winding system, capable of winding up to 3 reels on the same shaft.