Extrusion International 4-2026

27 Extrusion International 4/2026 EXTRUSION TECHNOLOGIES New Testing Method Developed The SKZ Plastics Center has developed a new testing method that signi cantly speeds up the determination of the permeability of plastic pipes. While conventional tests take several weeks or even months, the newly developed method delivers reliable measurement results within just a few hours. This opens up signi cant opportunities for pipe manufacturers in terms of quality assurance, testing costs, and development times. SKZ Develops Accelerated Test Method for Pipe Permeation Properties Plastic pipes are used for the safe transport of gases and liquids. Ideally, the transported medium reaches its desti- nation completely and unchanged. In practice, however, even minor material permeability poses a signi cant chal - lenge. So-called permeability – that is, a material’s ability to allow certain media to pass through – is therefore consid- ered a key quality characteristic in pipe manufacturing and is tested in accordance with standards. Standard-compliant permeation testing has been time-consuming to date Testing the permeability of pipes according to DIN 53380-3. Due to the geometry, material thickness, and the required steady-state measurement conditions, these tests often take several weeks to months. This represents a sig- ni cant time and cost factor, particularly in development, approval, and complaint resolution processes. IGF Project “Rohr-Perm” Enables Drastic Reduction in Testing Times In the IGF project “Rohr-Perm” (Project No.: 01IF22636N), funded by the Federal Ministry for Economic Affairs and Energy, the SKZ in Würzburg developed an alternative testing concept. The goal was to signi cantly shorten the testing time required to determine the permeation proper- ties of plastic pipes without compromising the reliability of the results. Test approach based on planar specimens and validated correlations At the heart of the new method is the examination of a planar chip taken from the pipe. Its permeability is deter- mined using established test methods for at specimens in accordance with DIN 53380-2, which allow for signi cantly shorter measurement times. Using correlation factors determined and validated in the project, the permeability of the entire pipe can then be reliably calculated. The correlation factors were system- atically determined by comparing measurements on pipes and chips according to different standards, as well as using a rapid helium test developed at SKZ. High correlation demonstrated for PE, PP, and PVC pipes The investigations on pipes made of polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) showed a high degree of agreement between the measurement re- sults from pipe and chip tests. Thus, the “Rohr-Perm” proj- ect makes a signi cant contribution to the accelerated and practical determination of the barrier properties of plastic pipes. “Especially for PP and PVC, we were able to demonstrate a signi cant correlation of results when using identical mea - surement gases. The developed method enables the pipe industry, for example, to reduce measurement time from several weeks to a few hours when testing oxygen perme- ability,” explains Franziska Eichhorn, Senior Engineer at SKZ. Greater ef ciency and quality assurance for the pipe industry The industrial bene ts of the new testing method lie particularly in the signi cant reduction of testing times and costs, as well as in the possibility of using permeation tests more widely in quality assurance in the future. “The project highlights the added value of methodologi- cal transfer. Established measurement methods from other product areas can – with appropriate validation – be sucess- fully successfully transferred to new applications. This often results in signi cant potential for ef ciency gains and cost savings,” emphasizes Dr. Linda Mittelberg, Head of the Quality and Lifecycle Division at SKZ. The SKZ Plastics Center www.skz.de and is performing very well. And we’ve done this without relying on external resources, but by developing our inter- nal talent. Furthermore, in light of the growing focus on environmental issues and in compliance with new Europe- an regulations in this area, the establishment in 2024 of our subsidiary ReFilm in collaboration with an industrial part- ner allows us to look to the future from new perspectives.” Plastotecnica www.plastotecnica.com