Bobst, Brückner, and Mitsui announce monomaterial metallized retort solution

Bobst, Brückner, and Mitsui Chemicals have unveiled “the world’s first“ monomaterial, recyclable retort solution, featuring high barrier properties based on opaque metallization.

The solution, announced at K 2025, Düsseldorf, Germany, is designed to integrate into existing recycling streams and to help packaging companies meet sustainability targets. 

Willi Lindemann, specialist inline coating, new technologies at Brückner, says: “While we have achieved a huge milestone, we haven’t finished the development of the solution yet. There’s still some work to do before this solution can become commercially available. But we are well on the right road.” 

“The next step may be to bring in further partners to ensure the solution is robust, repeatable, and production proof. In terms of the type of food this solution could be used for, it’s really any retort food — that is, food that is sterilized within the packaging. A good example is wet pet food.”

Combination of expertise

Brückner is offering its expertise in inline coated ultra-thin layers along with extrusion and orientation technology. Bobst is contributing to advanced metallization. Mitsui has the capabilities to develop a novel heat-resistant primer. 

Nick Copeland, R&D director for barrier solutions at Bobst, says: “Ultimately, we needed to create an ultra-thin, stretchable, heat-resistant barrier primer in combination with advanced opaque metallization.”

“The reels produced by Brückner in Germany on the inline coating pilot line were then delivered to Manchester in the UK for Bobst’s vacuum coating technology. We utilized the Bobst Expert K5 vacuum metallizer with AluBond technology, which is a novel vacuum metallizing technology with three key benefits — it improves the barrier, improves the adhesion, and maintains the surface energy over time.”

“The combination of the extremely thin inline coating together with extremely thin metallization achieves the high barrier performance. It was also very beneficial being able to test the inline-coated metallized material in our Competence Center in Manchester, UK, with our process experts available on hand.”

Overcoming challenges

The companies explain that until now, it has only been possible to maintain a high barrier in retort solutions using a composite layer structure consisting of polyester, aluminum foil, and various other materials.

“The most challenging part of producing a monomaterial retort solution is maintaining the barrier qualities after the retorting process, which happens under really high temperatures,” shares Anrika Heermant, senior specialist at Mitsui Chemicals Europe.

Lindemann adds that the perception in the industry was that it couldn’t be done. “It was generally assumed that metalized films could not be used for retort purposes without corrosion, because the high temperatures involved would lead to water ingress.”

“The other challenge with moving to monomaterial polypropylene is the risk of shrinkage, which would have a negative impact on the barrier properties. So, there was a lot to contend with.”