Researchers from four Fraunhofer institutes are developing a new manufacturing process that could improve the recyclability of paper packaging by eliminating the need for adhesives and plastic sealing layers.
The initiative, known as PAPURE, aims to enable fully paper-based packaging sealed using a laser-based process rather than conventional adhesives. The project brings together expertise from the Fraunhofer Institutes for Applied Polymer Research (IAP), Material and Beam Technology (IWS), Process Engineering and Packaging (IVV), and Machine Tools and Forming Technology (IWU).
Paper packaging is increasingly viewed as a sustainable alternative to plastic due to its high recycling rates and lower carbon footprint. However, many paper-based formats still require adhesives or plastic coatings to create airtight seals, introducing contaminants that complicate recycling and reduce fiber quality.
The PAPURE project addresses this challenge by modifying the surface of paper with a carbon monoxide (CO) laser. The treatment converts natural components such as lignin, hemicellulose and cellulose into short-chain compounds that act as a bonding agent. These compounds are then activated during heat sealing, allowing paper layers to bond without additional materials.
According to the research team, the process effectively creates a paper-derived bonding layer during production, enabling the use of established heat-sealing technologies while avoiding synthetic materials.
The project began with an extensive evaluation of coated and uncoated papers, including packaging grades, printing papers and paperboard. Researchers found that thicker paper grades are generally better suited to additive-free sealing, while high levels of inorganic fillers such as talc and calcium carbonate can reduce bond strength.
Fraunhofer IVV is developing the sealing system required to process laser-treated papers, while researchers are optimizing parameters such as temperature, pressure and dwell time. Mechanical testing has already produced promising results, with seals measuring just two centimetres in length and three millimetres in width supporting loads of up to 20 kilograms in shear tests.
To demonstrate industrial viability, Fraunhofer IWU is building a pilot-scale roll-to-roll production line capable of manufacturing four-sided paper bags. The modular system integrates both laser treatment and heat sealing and is designed for compatibility with existing packaging production environments.
Researchers aim to produce up to ten packages per minute on the pilot system by the conclusion of the project in September 2026. The technology was also showcased at Interpack 2026 in Düsseldorf, where its potential to support fully recyclable paper packaging and circular economy goals was highlighted.
The PAPURE process could provide packaging manufacturers with a viable route to producing fiber-based packaging without the recycling challenges associated with adhesives and plastic sealing layers.
Fraunhofer IVV is Europe's largest organization for applied research. With dozens of research institutes across Germany, Fraunhofer works with industry and public-sector partners to develop technologies in fields including manufacturing, materials science, energy, digitalization and sustainable packaging.
