Packaging: Reducing weight, keeping mechanical performance

Driven by economics and legislation, for example the European Packaging and Packaging Waste Regulation (PPWR) it is becoming desirable to decrease the weight of packaging and produce materials that are designed for recyclability, whilst keeping mechanical performance and optical properties at a high level.

Thus, ExxonMobil Signature Polymers has collaborated with industry experts in developing solutions to this end.

Reimagining cheese packaging with recyclable, mono-material

HFFS pouch Recently, ExxonMobil took the challenge to replace conventional multi-material cheese packaging, typically rigid trays with lid films, with a monomaterial PE pouch that is thinner, designed for recyclability, can provide the same shelf-life as existing cheese packaging and runs efficiently on horizontal form, fill & seal (HFFS) pouch-forming lines.

Machine maker Hosokawa Alpine’s latest ninelayer barrier blown film line, equipped with inline machine direction orientation (MDO) technology utilizing the vacuum system for ensuring excellent film processability, offers enhanced flexibility for film extrusion. On this single line, ExxonMobil Signature Polymers resins were used to produce both the MDO PE barrier substrate and the PE sealant film.

Thanks to Alpine’s advanced die head geometry and MDO capabilities, an ultra-thin 2 micron barrier layer was achieved using EVAL LT172B - a low ethylene EVOH grade suitable for orientation. This thin layer delivers strong barrier performance, supporting food shelf life.

The MDO PE barrier substrate film was reverse printed and laminated to the PE sealant film. The following high-performance resins were used:

The laminate film was converted into pouches on IMA Ilapak’s HFFS machine, engineered to handle both conventional polyester substrates and mono-material packaging solutions supporting next-generation packaging solutions.

The key resins used in the pouch were: MDO PE substrate film:

– Exceed HD 6107 – optimised for MDO processing
– Exceed Stiff+ m 0238.RA and Exceed Flow+ m 0938.RA – enhanced stiffness and tailored mechanical properties
– Exceed Stiff+ m 0820.RL – improved process stability

Sealant film:

– Exxtra Seal POP 2008.RK
– low seal initiation temperature and hermetic sealing
– Exceed Stiff+ m 0820.RL
– balanced stiffness and toughness - Exceed m 2018.RA
– ideal for lamination
– ExxonMobil HD 6207FL
– stiffness modification
– ExxonMobil LD 07523.AC
– enhanced processing stability

The resulting mono-material HFFS cheese package provides the following benefits:

Windmöller & Hölscher (W&H)/ExxonMobil create a 40% thinner non-laminated MDO PE freezer pouch

Meanwhile, a collaboration between ExxonMobil and German machine maker W&H was initiated to unlock the full potential of MDO PE, boosting stiffness and clarity, while ensuring the film stays tough and robust, even after MDO.

“In this collaboration, we set out to unlock the full potential of MDO PE — boosting stiffness and clarity — while ensuring the film stays tough and robust, even after machine-direction orientation,” said Corvin Hurtienne from W&H.

An improvement in robustness will supersede the need for lamination, which is an additional process step that can incur extra costs and lead to increased final packaging weights. Without further lamination, the MDO PE film must exhibit good sealing properties.

This collaboration was an opportunity to find solutions that go beyond traditional solutions for freezer film packaging applications.

Furthermore, the development of a fully monomaterial, well-sealable MDO PE freezer film offers a high-performance solution with superior film properties.This solution allows the production of thin films with superb optical properties, excellent mechanical performance even at demanding conditions such as freezer temperatures and good stiffness/toughness balance.

The significant boost in film performance enables downgauging and eliminates the need for lamination.

The mechanical performance was significantly enhanced, as demonstrated by exceptional pouch robustness under extreme testing conditions.The film maintained structural integrity during bag drop tests conducted at -30°C from a height of 6 m, confirming its high rupture resistance.

To support high-quality converting, the film was processed on a W&H Novoflex II press, achieving top quality and high-speed printing with inline slitting to ensure clean edges and optimal web control for seamless downstream processing.This makes the solution ideal for demanding frozen food packaging applications.

ExxonMobil Signature Polymers resins in the design provide:

The benefits of the resulting packaging include:

Thus, it can be seen that value partnerships are able to deliver enhanced mechanical properties and enable significant downgauging potential thereby improving operational efficiency across the value chain.

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