Cast MDO technology for mono-oriented polyethylene films is being positioned for mono-material packaging applications in the lead-up to K 2025. The approach combines a cast film process with in-line machine direction orientation, aiming to deliver tight thickness control across a broad range, high optical quality and configurable barrier functionality. In a recent development, SML reports MDO-PE films tailored for deep-freeze packaging that do not require lamination, supporting material downgauging while maintaining mechanical integrity and sealing performance. Reported operating windows include film thicknesses from 15 µm to 65 µm, line speeds up to 380 m/min and downstream printing at up to 500 m/min. The process setup features precise die regulation with thickness feedback after the MDO unit, high chill-roll cooling rates and edge-trim reprocessing to close the loop. For sensitive products, EVOH or PVOH barrier layers can be incorporated while preserving recyclability through low barrier-content ratios.
Deep-freeze applications without lamination
SML’s latest generation of cast MDO lines has produced an unlaminated MDO-PE film optimised for deep-freeze packaging. According to the company, this structure enables downgauging by up to 50 percent versus conventional deep-freeze laminates while retaining stiffness, puncture resistance and excellent sealing properties. The films are processed over a wide thickness range, from 15 µm to 65 µm, and have been printed at speeds of up to 500 m/min after production at up to 380 m/min.
Optimised resins and layer designs are cited as the basis for mechanical strength and sealability without the lamination step. Commenting on the joint work with a material supplier, Elias Mayrhofer, product manager, cast film extrusion at SML, said: "This joint development with TotalEnergies underlines SML’s ongoing commitment to innovation in cast MDO technology and sustainable flexible packaging solutions."
Precision and appearance
The cast MDO process yields films with high gloss, clarity and flatness, supported by a uniform thickness profile. Thickness is regulated via the die using measurements taken after the MDO unit, which helps compensate neck-in and supports stable winding. High cooling rates on the chill roll enhance surface smoothness and contribute to mechanical performance. Edge-trim recycling is integrated to facilitate a closed-loop material flow on the line.
Summarising the performance attributes, Mayrhofer added: "These unique performance features are unmatched by any other technology currently available on the market. The result is a premium mono-oriented film, ideal for demanding applications where visual quality and dimensional consistency are most important."
Barrier options and recyclability
For products requiring enhanced protection, a barrier layer based on EVOH or PVOH can be integrated into MDO-PE film structures. Cast MDO-PE barrier films are available in thicknesses from 17 µm to 65 µm. Compared with unstretched barrier structures, the orientation process improves barrier performance at the same EVOH content. Due to the low share of barrier material in the total structure, the films are designed to maintain recyclability within mono-material PE streams.
