Glue-Free Paper Sealing Gains Ground as Recycling Rules Tighten

The technology faces hurdles. Existing packaging machinery is built for glue materials. “Some kind of redesign is probably necessary, and this is our biggest challenge,” Baumann said. Volker Franke, also a research group leader at Fraunhofer, said existing machines can be modified by integrating the PAPURE laser module. Both acknowledged production speed is slower than adhesive-based packaging. Franke said fully automated production should allow for faster throughput.

The technologies do not work on all paper types. “It's not possible to bond every paper material,” Baumann said. “We are actively in discussion with paper manufacturers about how they can produce a raw material in a way that makes it easy to bond.” PAPURE has not yet found a way to apply its laser sealing to food-grade packaging, which requires a protective coating – the reason plastic is often used for food packaging.

Henkel has addressed that gap. In February, the company launched the first cold seal solution that works with barrier-coated paper, making it both recyclable and suitable for food products. Barrier paper is difficult to bond, and heat is unsuitable for temperature-sensitive foods like ice cream or chocolate. Henkel’s cold seal uses pressure to bond the coated paper against itself. The solution is already being used in snack and confectionery products, though Henkel declined to name the brands.

Henkel previously developed a fully recyclable heat seal solution for paper. Italian brand Regina used it to switch from plastic to paper packaging for toilet roll, kitchen paper and napkins.

“Since paper is already very established in the recycling infrastructure, it's a very obvious solution when we think about how we can improve the sustainability and recyclability of our packaging,” said Dr. Arianna Savini, market strategy manager for paper packaging Europe at Henkel’s adhesive technologies division. “This is really a system shift. You need to engage with all the players in the supply chain to enable this change. There is good momentum in the industry now because of the PPWR deadline.”

Jamie Stone, a packaging expert at global innovation consultancy PA Consulting, said multiple surfaces in a single package must work together. “Take a yoghurt pot made from folded paper fibre. You need a barrier layer between the paper fibre and the yoghurt to protect the shelf life, and you also need a secure lid,” he said. “If the barrier layer is a liner, it needs to be very thin. It also needs to bond really well to the paper fibre part. If it doesn't stick well enough, you risk pulling out the lining with the lid still attached – leaving a messy, partially sealed pot of yoghurt.”

Ambarish Mitra, co-founder of waste analytics platform Greyparrot, said the bigger problem is collection and sorting. “A lot of paper and card doesn't get recycled because it gets dirty or mixed in with other rubbish before it even reaches a recycling plant, not because of the glue holding it together,” he said.

Stone called the new sealing technologies “a smart place to start.” He said the real sustainability benefits will scale as the technologies mature and handle more complex, high-barrier paper-based packaging while matching the speed and cost of plastic packaging lines.