At K 2025, Bobst, Brückner, and Mitsui Chemicals unveiled a ‘breakthrough’ that they said could reshape the future of sustainable packaging—the world’s first mono-material, recyclable retort solution with high barrier properties based on opaque metallization.
The collaboration brings together three leaders in packaging technology, each contributing unique expertise to solve one of the toughest challenges in flexible packaging—making retortable pouches fully recyclable.
In a blog post, Nick Copeland, R&D director, Barrier solutions at Bobst, Willi Lindemann, Specialist Inline Coating, new technologies at Brückner, and Anrika Heermant, senior specialist at Mitsui Chemicals Europe, discussed the new solution and its potential impact on the packaging industry.
Explaining the significance of the product, Nick Copeland said it’s a novel mono-material retort solution with high-barrier properties based on special opaque metallization, which will be easily recyclable in existing recycling streams.
“Recyclable retort packaging is one of the final key challenges in sustainable flexible packaging. Together, we’ve achieved an important milestone, demonstrating that our solution can withstand the retort process and maintain high barrier qualities,” Copeland said.
Creating a recyclable retort solution has long been a technical roadblock. As Anrika Heermant of Mitsui Chemicals Europe, noted that up until now, it has only been possible to maintain a high barrier in retort solutions using a composite layer structure of polyester, aluminum foil, and other materials. “The most challenging part was maintaining those barrier qualities after retorting, which occurs under very high temperatures.”
Willi Lindemann of Brückner said the industry had long assumed metallized films couldn’t survive the retort process. “It was generally assumed that metallized films could not be used for retort purposes without corrosion because the high temperatures involved would lead to water ingress,” he said. “The other challenge with mono-material polypropylene was the risk of shrinkage, which would impact the barrier properties.”
Each partner brought a key innovation to the project. “We needed an ultra-thin, stretchable, heat-resistant barrier primer combined with advanced opaque metallization,” said Copeland. “Brückner provided state-of-the-art extrusion and orientation technology for ultra-thin inline coatings, while Mitsui developed a heat-resistant primer. Bobst contributed our advanced vacuum metallization expertise.”
Lindemann explained Brückner’s role further, “Through our inline coating technology, we can stretch primers to create very thin, metal-receptive layers. The key was finding the right hardness to ensure stretchability and resistance to retort conditions.”
Once Brückner produced the reels in Germany, they were sent to Bobst’s Manchester facility for metallization using the Expert K5 vacuum metallizer with AluBond technology—enhancing barrier strength, adhesion, and surface energy stability, Copeland explained.
Heermant highlighted Mitsui’s contributions, “We provided two grades of our Takelac water-based polyurethane dispersion—one as a top coating to protect the AluBond layer and one as a primer for heat resistance. We also supplied Admer, a grafted polyolefin resin that improves adhesion.”
Testing proved the new structure’s strength. “We’ve achieved proof of concept,” said Heermant. “The solution withstands the retort process while maintaining barrier performance, with excellent oxygen and water vapor transmission rates and adhesion results.”
Although not yet commercially available, Lindemann said, “We’re well on the right road. The next step is to bring in further partners to ensure robustness and production readiness.” He noted that the solution could be ideal for retort foods such as wet pet food.
The partners see this innovation as a step toward compliance with new sustainability regulations. “The industry urgently needs solutions like this,” Heermant emphasized. “Mixed materials will soon be non-compliant in many applications.”
Copeland is his concluding remarks said it worked because each partner is a leader in its field. “With mutual trust, advanced facilities, and dedicated experts, we’ve accelerated development and are eager to keep pushing boundaries together.”
