Fraunhofer Develops Laser Based Adhesive Free Sealing Technology for Fully Recyclable Paper Packaging Production

© Fraunhofer IVV
Process for sealing a laser-modified paper web without additives

(IN BRIEF) Fraunhofer researchers are developing an adhesive-free sealing technology for paper packaging through the PAPURE project, enabling fully recyclable packaging without plastic coatings or adhesives. The process uses a carbon monoxide laser to modify paper surfaces so they can be sealed using conventional heat-sealing methods. Four Fraunhofer institutes are collaborating on the project, covering material analysis, laser processing, sealing technology and industrial implementation. Tests have shown that thicker papers with lower inorganic content provide the best sealing performance, and strong seam bonds have already been demonstrated. A pilot production system is being developed in Dresden to demonstrate industrial feasibility and is expected to produce up to ten packages per minute by 2026. The technology can be integrated into existing packaging lines and will be showcased at Interpack 2026.

(PRESS RELEASE) MUNICH, 3-Mar-2026 — /EuropaWire/ — Fraunhofer researchers are developing a new laser-based process that enables paper packaging to be sealed without adhesives or plastic coatings, offering a fully recyclable alternative to conventional packaging materials. Through the PAPURE project, four Fraunhofer institutes are working together to create a manufacturing method that improves recyclability while maintaining the efficiency and practicality required for industrial packaging production.

© Fraunhofer IVV
Paper reel downstream of the sealing module. The cutouts for the four-sided bags are clearly visible.

Paper packaging already offers environmental benefits such as high recycling rates, lower carbon emissions, and reduced disposal costs compared with plastic. However, most paper packaging still requires adhesives or plastic layers for sealing, which contaminate the material and complicate recycling processes. The PAPURE project addresses this limitation by modifying paper surfaces with laser treatment so that the material can be sealed directly using heat, eliminating the need for additional substances.

The project combines the expertise of the Fraunhofer Institutes for Applied Polymer Research IAP, for Material and Beam Technology IWS, for Process Engineering and Packaging IVV and for Machine Tools and Forming Technology IWU. Each institute contributes a specific area of expertise: Fraunhofer IAP analyzes and characterizes paper materials, Fraunhofer IWS develops the laser-based modification process, Fraunhofer IVV designs the sealing technology, and Fraunhofer IWU builds an industry-oriented demonstrator system. A laboratory-scale manufacturing line is being constructed in Dresden to replicate the production of typical packaging materials.

© Fraunhofer IVV
Sealed paper bag packaging

Fraunhofer IAP researchers first examined a wide range of paper types to determine their suitability for additive-free sealing. Approximately thirty different papers, including coated and uncoated packaging materials, printing paper and cardboard, were analyzed. Particular attention was given to the content of cellulose, hemicellulose and lignin, which strongly influence bonding behavior and the reaction products created during laser treatment. Using methods such as scanning electron microscopy, high-performance anion exchange chromatography and X-ray photoelectron spectroscopy, scientists studied both untreated papers and laser-treated samples. The results showed that papers with high inorganic filler content, including talc and calcium carbonate, produce weaker bonds, while thicker papers offer improved sealing performance. Many commercially available packaging papers were found to be suitable for the new process.

Fraunhofer IWS researchers then developed a surface modification method using a carbon monoxide laser. The laser rapidly heats the paper surface, converting natural components such as lignin, hemicellulose and cellulose into short-chain compounds. These reaction products remain on the paper surface and act as fusible bonding agents. When heat and pressure are applied through a conventional thermal contact sealing process, the modified surfaces bond together without adhesives or synthetic materials.

Fraunhofer IVV is developing the sealing system needed to process the laser-treated papers. Researchers are studying how paper characteristics, laser settings and sealing parameters influence seam strength and leak-tightness. Key process variables include sealing temperature, sealing time, pressure and tool geometry. Mechanical tests such as shear and T-peel measurements are used to evaluate seam durability under different loads. Strong results have already been achieved, with seals measuring just two centimeters in length and three millimeters in width capable of supporting loads of up to 20 kilograms. Fiber orientation relative to the sealing tool has also proven to be an important factor in seam performance.

Fraunhofer IWU is building a modular pilot production system that demonstrates how adhesive-free sealing can be integrated into industrial packaging lines. The laboratory-scale demonstrator replicates a roll-to-roll process used to produce flat four-sided bags. The industrial-type installation incorporates both a laser module and a sealing module within a system approximately six meters long. During operation, a moving paper web is first treated with the CO laser to generate fusible reaction products. A second paper web is then added and joined through a combined sealing and punching tool before being cut into finished packages.

Sensors commonly used in industrial production, including imaging and moisture monitoring systems, support process optimization together with a digital twin and trained data model. A seal seam measurement system planned for the pilot plant will enable real-time monitoring of seam quality and allow rapid adjustment of process parameters. By the completion of the project in September 2026, the researchers aim to achieve a production rate of ten packages per minute on the demonstration system.

The modular demonstrator shows that the adhesive-free sealing technology can be incorporated into existing production environments. The laser and sealing modules can also be implemented separately, making the process adaptable for packaging machine manufacturers, packaging material producers and packaging companies seeking sustainable alternatives. Industry partners are working with the research teams to prepare the technology for large-scale manufacturing.

Fraunhofer researchers will present the PAPURE technology and demonstrate its capabilities at Interpack 2026, taking place May 7–13 in Düsseldorf, where visitors will be able to see the system in operation and explore its potential applications in sustainable packaging production.

Media Contact:

Karin Agulla
Fraunhofer Institute for Process Engineering and Packaging IVV
Giggenhauser Straße 35
85354 Freising
Phone +49 8161 491-120
Fax +49 8161 491-222
karin.agulla@ivv.fraunhofer.de

SOURCE: Fraunhofer-Gesellschaft