A revolutionary new manufacturing process developed by German researchers at the Fraunhofer institutes can seal paper packaging without relying on adhesives or plastics. This innovation, known as the Papure project, turns paper compounds into a natural adhesive through the use of carbon monoxide lasers.

The first step involves analyzing various paper types using advanced techniques such as scanning electron microscopy and X-ray photoelectron spectroscopy to determine their suitability for seal-free packaging. The amounts of ingredients like hemicellulose, cellulose, lignin, talc, and calcium carbonate in the paper play a crucial role in the strength of the final seals.

In the controlled process, CO lasers heat the paper's surface rapidly, converting lignin, hemicellulose, and cellulose into short-chain compounds. These 'fusible cleavage products' act like natural glue, allowing for tight seals when heat and pressure are applied. The researchers are fine-tuning this process to maximize bond strength, with current testing showing that a 2cm seal just 3mm wide can support a significant load of 44 pounds.

Building on the success of the laboratory-scale modular paper processing manufacturing unit, which has produced a flat four-sided paper bag design used by companies like Lego, researchers are now working to streamline and shrink the laser and sealing modules. They are integrating measurement systems that can assess seal quality and automatically adjust settings to ensure specific bond strength targets are met. By September, their goal is for the pilot machine to produce 10 packages per minute.