Extrusion International 5-2025-USA

13 Extrusion International 5/2025 Accelerated Prediction of the Media Stress Crack Resistance of Plastics A pioneering research project has been successfully com- pleted at the SKZ Plastics Center. The aim of the project was to develop a time-lapse testing method that, for the rst time, enables the quantitative evaluation of stress crack failure in plastic components under the in uence of media. Unlike established, standardized test methods – such as the ISO 22088 series of standard – which generally only allow material ranking, the new test concept enables a well-founded prediction of service life. This represents a signi cant advance for quality assurance and product de - velopment in the plastics processing industry. Stress crack failure, which occurs under the simultaneous in uence of mechanical stress and chemical media, is one of the most common causes of damage to plastic components. The methods standardized to date, such as ISO 22088, generally only allow for qualitative material ranking. Un- til now, it has been virtually impossible to reliably predict service life. As part of a research project funded by the German Feder- al Ministry for Economic Affairs and Climate Action (BMWK), the SKZ plastics center has now succeeded in developing and validating a new testing and evaluation concept. This en- ables, for the rst time, a quantitative assessment of stress crack behavior under realistic conditions. Themethod allows statements to be made about when a plastic will fail under de ned test conditions, such as medium (e.g., disinfectants, oils), load level, and temperature. The basis is a specially de- veloped, heatable measuring setup that can be adapted to common universal testing machines. The test can be acceler- ated considerably by raising the temperature in a targeted manner (time-temperature superposition principle). The measurement setup with continuous force and strain measurement offers a particular advantage: in addition to failure times, the in uence of stress duration and medium on stiffness can also be investigated – for example, through the effect of plasticizers. Processing-related factors such as resid- ual stresses or molecular orientations can also be evaluated. The project was funded by the Federal Ministry for Eco- nomic Affairs and Climate Protection (BMWK) under the Industrial Collective Research (IGF) program and supported by a committee of interested companies. In a supplementary R&D cooperation project with IPT In- stitut für Prüftechnik Gerätebau GmbH & Co. KG – funded by the Central Innovation Program for SMEs (ZIM) – a cor- responding test device with several measuring stations was developed. In its current version, the new test device has six autonomous measuring stations. This allows parallel tests with different media, plastics, or test conditions (tempera- ture, test type, test parameters). It is now available at SKZ for industrial applications to perform (time-lapse) tests for the quantitative assessment of the media stress crack resistance (failure times and creep deformation) of plastics. With this development, SKZ is making an important con- tribution to damage prevention in plastic components. The SKZ Plastics Center Dr.-Ing. Kurt Engelsing, k.engelsing@skz.de Partnership Expanded Songwon Industrial announced that it has expanded its longstanding part- nership with Biesterfeld Spezialche- mie GmbH. Since July 1st, 2025, Biesterfeld Spe- zialchemie is the exclusive distributor for SONGWON’s full range of polymer stabilizers in the strategically impor- tant markets of Romania, Bulgaria, Croatia, Montenegro, Bosnia & Herze- govina, Kosovo and North Macedonia. The expanded cooperation will not only broaden SONGWON’s footprint but also improve product availability and customer service across the region. “Biesterfeld has been a strong part- ner to SONGWON for many years. Ex- panding our collaboration to include these seven Southeastern European countries is a signi cant step toward growing SONGWON’s market posi- tion and reach with products that not only meet, but exceed the expecta- tions of our customers in the region,” said Albert Dantuma, Leader Sales Polymer Stabilizers at SONGWON. “Leveraging our technical expertise and strong local presence, we are ide- ally positioned to provide customers across Europe with reliable access to SONGWON’s high-performance prod- ucts and the comprehensive, high- quality service they require,” adds Jürgen Rietschle, Head of Sales - Poly- mer Additives at Biesterfeld Spezial- chemie. Songwon Industrial Co., Ltd. www.songwon.com Newly developed testing facility (consisting of six independent measuring stations) for determining the in uence of media on the stress crack resistance of plastics (Photo: Luca Hoffmannbeck/SKZ)