Case study: Sustainable plastic packaging with MDO technology - Interplas Insights

by Daniel Ball

22 February 2023

15:49

The new 7-layer blown film line with inline MDO from Hosokawa Alpine installed at ManuliTech near Milan.

With the laminating and laminate films with oxygen barrier in full PE design produced by the 7-layer line with inline MDO from Hosokawa Alpine, ManuliTech offers solutions for recyclable plastic packaging.

ManuliTech, based in Cambiago near Milan, produces multilayer blown films for customers primarily in the food and pharmaceutical industries. The company has undergone a rapid rise tosuccess; in 2018, production capacity was around 12,000 tonnes, and in 2019, it was increasedto 15,000 tonnes.

"ManuliTech has achieved a very high level of quality within a very short time," said NicolaPirani, Alpine's representative in Italy. The first Alpine line was installed at the site in northern Italy in 2020. The quality of the film produced from that line has been a key part of the firm’s rapid group, according to Alpine. This was followed last year by the construction and configuration of the new, flexible 7-layerhigh-performance line with inline MDO to meet the emerging demand for full-PE films in Italy. "The market for full-PE barrier films is growing in Italy, but it is still difficult for end-customers to get these films in consistently good quality and sufficient quantity," Pirani said. ManuliTech targeted this gap in the market with its capital investment.

In many cases, in order to achieve the desired product properties in these applications, composites have needed to be produced from different materials that cannot be fully recycled. Full PE packaging with films made from pure polyethylene composites, however, can be fully recycled after their original use and reused without material loss for end products, making for amore sustainable product, and resource efficiency. "We support this circular economy approach and offer our customers suitable solutions for it," said Alessandro Manuli, managing director at ManuliTech. "This is a long-needed development for the sustainability principle and a promising growth market for us," he added.

"More than 100 MDOs made by us are in operation worldwide," said Stefan Sager, operations director in the film extrusion division at Hosokawa Alpine. The technology was first introduced25 years ago. Working with its customers, Hosokawa Alpine designs each MDO blown film line to fit the desired film production, tailored to the customer's needs. "That's one secret to our success, the other is the quality of MDO film," said Sager.

Alpine claims that film produced on its equipment is characterised by excellent processability, optimised flatness and no hanging edges. To achieve this, the MDOs are equipped with three features: TRIO technology (Trim Reduction for Inline Orientation) for best flatness and roll cylindricity, flexible stretch gap adjustment to reduce neck-in, and unique vacuum technology for best flatness and excellent process stability.

Hosokawa Alpine MDO technology is based on monoaxial stretching of blown film. In this process, the film is drawn between two rolls which rotate at different speeds. Depending on the application, the film runs over eight to twelve rolls, two of which are stretching rolls. After heating to the optimum temperature, the film is brought to the desired ratio in the stretching phase. The stretching process reduces the film thickness while improving its optical and mechanical properties. These include, for example, barrier properties, transparency or processability. "This technology reduces the need for raw materials in a resource-saving way, while also increasing efficiency," said Sager. The stress created during stretching is reduced in the subsequent annealing phase. Finally, the film cools down and compensates for the thermal shrinkage.

TRIO increases finishing quality

The TRIO system integrated into the line reduces neck-in by up to 50 percent. At the same time, the flatness of the film is optimised, and a uniform thickness profile is produced. "TRIO 2.0" is a further development of the system and is now on the market. It includes single-layer measurement of the stretched film after slitting and before the winding points. "This more precise detection of the film layers enables even better positioning of the thin sections for the stretching process," emphasizes Sager. A smart control algorithm calculates an improved mapping of the influences from the MDO on the entire control loop from the measured values. The optimised recording and calculation of the target values for the thin sections makes the control in the inline MDO process more precise and thus increases the further processing quality.

Trend-setter

ManuliTech uses the new blown film line to produce monomaterial films from polyethylene. When an oxygen barrier is needed, ethylene vinyl alcohol plastic (EVOH) is used as a barrier layer. If the EVOH content of a film is less than 5 percent, it does not affect recyclability in thePE waste stream. "Alpine is not only a pioneer in MDO technology, but also a market leader. We are pleased that, together with this competent partner, we have been able to integrate anew, future-oriented component into our product range," said managing director Manuli.

by Daniel Ball

22 February 2023

15:49