Windmöller & Hölscher and its partners have developed what it says is a fully recyclable, mono-material PE pouch, which has similar properties to standard multi-material laminated pouches.
According to the company, the new pouch uses the latest polymers, inks, functional coatings, adhesives and conversion technology, and is the product of a value chain collaboration of ExxonMobil, Henkel, Kraus Folie, Siegwerk and Windmöller & Hölscher.
W&H says that the innovation allows for pouches that provide a high oxygen barrier, good package integrity and shelf-appeal, and produces an almost colourless recyclate after the removal of printing ink and the oxygen-barrier coating layer.
In order to produce a colourless recyclate, the delamination and removal of the printing ink and coating from the laminate structure is crucial, which is why Siegwerk´s delamination/deinking primer technology was applied on a Windmöller & Hölscher MIRAFLEX II, a flexo printing press with a downstream unit.
Depending on the requirements either solvent-based (SB) or water-based (WB) primer from Siegwerk´s CIRKIT ClearPrime product range are available. Applying industrial hot-washing conditions enables delamination and deinking of the pouch, giving an almost colourless recyclate.
The company claims that excellent oxygen barrier properties have been achieved through the use of Loctite Liofol BC 1582 RE, a recently introduced 1-component barrier coating from Henkel, and CIRKIT OxyBar BC 1582 from Siegwerk. The coating can be applied on both flexo and gravure presses at industrial machine speeds on various substrates, giving transparency. To match these requirements, appropriate coloured and white inks from Siegwerk were used.
To improve recyclability, the company says its partners used Henkel’s new solvent-free, 2-component polyurethane laminating adhesive, LOCTITE LIOFOL LA 7102 RE / 6902 RE. The system has been designed for mono-material structures.
According to the company, high primer transparency combined with consistent print quality and the inherent gloss of the ExxonMobil PE-based MDO film helps to deliver an excellent shelf appeal of the final pouch. Deinking primer, print image and barrier coating had been applied in one step using a Windmöller & Hölscher MIRAFLEX II with a downstream unit.
