Extrusion International 2-2025

49 Extrusion International 2/2025 "For us, these are the key elements of a functioning circular economy," adds Grefenstein. Production of high-performance mono-material composites made of polyethylene Hosokawa Alpine’s MDO tech- nology is a crucial building block for the production of high-perfor- mance monomaterial composites from polyethylenes and is based on the monoaxial stretching of blown lms. Here, the lm is pulled be - tween two rollers that rotate at different speeds. Depending on the application, the lm runs over a total of eight to twelve rollers in this process, two of which are stretch rollers. After heating to the optimum temperature, the lm is stretched to the desired stretch ratio during the stretching phase. The stretching process reduces the lm thickness while improving the optical and mechanical properties. These include, for example, trans- parency or amenity to processing. "MDO lms alsohavean improved barrier effect due to the orientation in the material. This keeps packaged products fresh and protected for longer," explains Frank Bernotat, Senior Sales Manager at Hosokawa Alpine. "MDO also allows us to re- duce the thickness and therefore the amount of material used in the PE lms - without compromising on mechanical performance," adds Prof. Grefenstein. This is particularly important for subsequent process steps such as printing or laminating. Technical challenges with regard to thickness pro le and atness were continuously improved in the joint further development of the system by Constantia Flexibles and Hoso- kawa Alpine, as the quality of the blown lm has a strong in uence on the further processing steps. Customised system design and high lm quality "More than 100 of our MDOs are now in use around the world," says Bernotat. Working with the custom- er, Hosokawa Alpine designs the respective MDO blown lm line pre - cisely for the desired lm produc - tion, customised exactly to the cus- tomer's needs. "This was also the case at Constantia Flexibles and is ultimately the secret of our success. The other is the quality of the MDO lms," says Bernotat. It is character - ised by excellent workability, opti- mised atness and no hanging edg - es. To ensure this, the MDOs from Hosokawa are equipped with three unique features: TRIO technology (Trim Reduction for Inline Orienta- tion) for optimised atness and roll cylindricity, exible adjustment of the stretching gap to reduce neck- ing and the unique vacuum technol- ogy for optimum atness and out - standing process stability. Targeted adjustment of barrier properties "Typically, the MDO PE lm is combined with a PE sealing lm," says Prof. Grefenstein. If you want to increase the barrier against oxy- gen and water vapour, an addition- al metallised MDO-PE lm can also be integrated into the composite. "This allows our customers to cov- er a wide range of applications," emphasises Bernotat. An impor- tant prerequisite for metallising a lm is very good atness, which is achieved by the vacuum roller from Hosokawa Alpine. Mono-PE lms retain their recyclability even when laminated. In Constantia Flexibles' proprietary formulations, for ex- ample, only minimal quantities of necessary barrier layers and other functional layers are used. Good prospects for the future The market for MDO lms and mono PE lms has grown steadily in recent years and is expected to continue to develop positively in the future. "The growing demand for sustainable packaging solutions and increased consumer awareness of environmental issues will fur- ther accelerate this trend towards a circular economy," predicts Prof. Grefenstein. "Our MDO technology makes a signi cant contribution to reducing plastic consumption and promoting recyclability, making it an attractive option for the packag- ing industry," concludes Bernotat. Author Susanne Schwenk, Project Manager Marketing Film Extrusion, Hosokawa Alpine AG Hosokawa Alpine AG Peter-Doer er-Str. 13 – 25 86199 Augsburg, Germany www.hosokawa-alpine.com The MDO technology from Hosokawa Alpine is based on monoaxial stretching of blown lm. The mono PE lms produced in this way reduce plastic consumption and have improved optical and mechanical properties