Image source, Getty Images Image caption, Europe is introducing stricter targets on paper and card recycling
It's quite literally a sticking point.
While paper or cardboard packaging might on its own be recyclable, the presence of a label, a seal or a coating can negate that.
That's because non-recyclable adhesives, or "stickies" as they are known as in the industry, can cause damage to recycling machinery, make the resulting batch of recycled paper inferior, or even cause a batch of paper to be recycled to be rejected, according to scientists , external at NC State University.
And that's a shame as 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 , external 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 , external require stricter reporting and licensing fees.
So, tackling stickies would be helpful. One solution has been to develop water soluble adhesives , external .
Image source, Fraunhofer Image caption, Fraunhofer has developed a laser-based sealing process
But what if you could skip the adhesive altogether?
That's the idea that three firms from Germany - Fraunhofer, Hermann Ultraschall, and Henkel - have come up with.
It's no coincidence they are all German, as the country is known for its Packaging Valley , external , 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 packaging.
"One customer told me this is an innovation they have never seen before."
Yet these seemingly simple solutions stem from complex technology, so naturally, there are challenges.
Firstly, it's not as simple as simply getting product manufacturers and packaging companies to swap out their old packaging for these new options. It requires updating, and in some cases, completely replacing, existing machinery, which can be costly and time consuming.
"The packaging industry has existing machines wh…