en.Wedoany.com Reported - The University of Oulu in Finland is developing a coating material derived from suberin, a natural compound found in birch bark, for moisture barrier applications in fiber-based packaging materials, and has completed testing in collaboration with UPM and Metsä Board. The coating has produced prototype materials up to 1,500 meters in length at semi-pilot scale.

The research is part of the two-year COCOBIN project, co-funded by Business Finland and coordinated by the University of Oulu, with a consortium of 15 research and industry partners and a total project budget of approximately €8.7 million.

The coating is suitable for substrates such as paper or paperboard and primarily serves as a moisture barrier layer, particularly for food packaging applications—where the coating needs to prevent moisture from penetrating the packaging material to protect the packaged product.

In terms of the process, the team first extracts suberin from birch bark at semi-pilot scale, dries it, processes it into a fine powder, and then blends it into a uniform coating formulation. According to the University of Oulu, the powder is subsequently used to produce a water-based coating in which suberin particles are evenly distributed in the liquid; other components are also added to the formulation to help the coating spread evenly and achieve the required functional performance.

Both coating production and testing were carried out on semi-pilot scale equipment, which simulates industrial production conditions on a smaller scale, allowing the team to observe how the material performs in an environment close to actual manufacturing. The coating was applied to two wood-fiber paper substrates from UPM and Metsä Board, and multiple trial runs were conducted, with each run producing several hundred meters of material, totaling approximately 1,200 to 1,500 meters of coated length.

The University of Oulu states that the trials demonstrated the coating can be processed in a manner similar to conventional coatings, and production scale can be extended beyond laboratory level. The research team is currently analyzing the coating material to further understand its performance in different applications.

Rajesh Koppolu, Senior Scientist at VTT Technical Research Centre, commented that suberin-based coatings can serve as water vapor barriers in food packaging applications. Existing coating materials are largely fossil-based and may pose challenges for recycling; suberin-based coatings offer an alternative while achieving comparable performance.