It is quite literally a sticking point. While paper and cardboard packaging may be recyclable on their own, the presence of a label, seal or coating can negate that, because non-recyclable adhesives – known in the industry as “stickies” – can damage recycling machinery, degrade the quality of recycled paper, or even cause an entire batch to be rejected, according to scientists at NC State University.
This is a particular shame given that paper is one of the most recycled materials in Europe, with around 74% of paper and board consumed in 2024 being recycled. And European authorities are spurring firms to do better. In August, a new Europe-wide packaging and packaging waste regulation (PPWR) kicks in ordering that all packaging should be minimum 70% recyclable by 2030, rising to 80% from 2038. In addition, German law will also require stricter reporting and licensing fees.
“German firms develop laser and ultrasonic tech to seal paper packaging without glue, tackling recycling's 'stickies' problem.”
So tackling stickies would be helpful. One solution has been to develop water-soluble adhesives. But what if you could skip the adhesive altogether? That is the idea that three firms from Germany – Fraunhofer, Hermann Ultraschall, and Henkel – have come up with. It is no coincidence they are all German, as the country is known for its “Packaging Valley”, a hub for the packaging industry. Their efforts to innovate are partly a bid to satisfy ever tightening regulation around commercial recycling, and rising fines for those who fall foul.
With that in mind, German research organisation Fraunhofer established the PAPURE project in 2023 to develop a laser-based heating process that can seal paper packaging without an adhesive at all. From September, when the project is set to officially close, Fraunhofer hopes to find an industry partner to take the technology to market. Fraunhofer researchers exhibited their work at the Interpack packaging trade show in Dusseldorf in May, and are hopeful that the interest they attracted will come to fruition.
“There are not really many paper sealing technologies without any foreign materials, so it’s a great technology and we feel it’s likely that we can bring it to market,” says researcher group leader Fabian Kayatz. “If we are optimistic, we will have the first solution out in two years.”
Also in 2023, engineering firm Hermann Ultraschall bought the rights to develop a patented ultrasonic paper sealing technology, a process which it likens to welding. “We are really actively at the moment in discussion with several really big players in the market with the focus of bringing this technology into mass production,” says Michael Baumann, the company's head of business development.
As European regulations tighten, the race is on to make paper packaging truly recyclable – and German engineering may have found a way to peel off the sticky problem for good.