As demand grows for sustainable alternatives to plastic packaging, paper has emerged as a leading candidate because it is lightweight, recyclable, and biodegradable. But sealing paper packaging typically requires adhesives or plastic additives, which contaminate the fibers and reduce the quality and efficiency of recycling. That challenge is central to the PAPURE project, in which four Fraunhofer institutes are collaborating to develop a way to seal paper packaging without any additives. The aim is to preserve paper’s recyclability and avoid the environmental drawbacks posed by traditional sealants, tells Tech Xplore.
The project brings together expertise in polymer science, laser surface modification, packaging systems, and manufacturing technology. Researchers are using laser treatment to alter the surface of paper so that it can fuse directly during heat sealing, eliminating the need for glue or plastic films. Scientists first assess the composition of a wide range of papers, including coated, uncoated, printer papers, and cardboard, because components such as cellulose, hemicellulose, and lignin influence how laser-induced changes occur and how well the paper bonds during sealing.
Analytical techniques such as scanning electron microscopy, anion exchange chromatography, and X-ray photoelectron spectroscopy help characterize these papers before and after laser treatment, revealing how chemical composition and microstructure respond to laser-induced changes. With these insights, teams are designing a process that pairs laser-modified paper surfaces with a heat seal system that can produce reliable seals without adhesives. A laboratory-scale manufacturing unit at Fraunhofer IWU in Dresden replicates typical packaging production conditions to test the approach and pave the way for industrial implementation.
By eliminating additives that hinder recycling, this innovation could simplify paper packaging recycling streams and enhance material circularity. If scalable, the additive-free sealing method might reduce waste, cut contamination, and strengthen paper’s role as an eco-friendly choice for packaging, aligning with broader industry and consumer demand for sustainable materials.