Here - Polyurethanes - Bayer

More documents

Recommendations

Info

Baydur ®/Bayflex ® – Polyurethanes for Design and Functionality A MATERIAL THAT POINTS THE WAY FORWARD Wood, one of the oldest materials known to man, is also one of the most fascinating. However, this popular material does have its limits in terms of what it can be used for. Being a natural raw material, wood is not resistant to weathering. Its high tendency to warp has also forced engineers to look for alternatives in some areas where wood is traditionally used. “Eslon Neo Lumber FFU” is an extremely dimensionally stable composite material based on Baydur ® 60 reinforced with long glass fibers. It is produced by Sumika Bayer Urethane Co. Ltd., a subsidiary of Bayer MaterialScience AG. The Japanese company Sekisui Chemical has been successfully selling this product for over 20 years as a construction material for the Asian market. There, the sophisticated composite material has proved its worth in a wide variety of applications, particularly where technical considerations mean that it is not practical to use wood, but where the engineers would still like to benefit from the ease of processing associated with wood. Common applications include pools for fish farming, silos, walkways, soil anchors (where it is used as a substitute for concrete) and, above all, railway sleepers. European debut: The Zollamt bridge in Vienna has been fitted with polyurethane railway sleepers Now, this versatile material has made its debut in Europe. As part of a renovation project, the tracks on the Zollamt bridge in Vienna have been laid on sleepers made from polyurethane. “Eslon Neo Lumber is particularly well suited to use on bridges as it offers clear advantages over wood,” says Max Nakai from Sekisui Chemical Deutschland. “Changes in temperature, UV radiation and in particular the fact that the air is always humid mean that wooden sleepers weather more quickly here than in other applications. The problem is that carrying out structural repairs to railway tracks not only involves considerable inconvenience but is also very expensive.” The Zollamt bridge in Vienna This is also the case with the Zollamt bridge, which was designed by the Viennese art nouveau architect Otto Wagner and was constructed in 1898 when the Viennese city rail network was built. Materials with a long service life quickly pay for themselves in applications like this. Sekisui produces the polyurethane-glass fiber compound FFU (FFU
Baydur ®/Bayflex ® – Polyurethanes for Design and Functionality stands for fiber-reinforced foamed urethane) using the pultrusion process. The material can be produced to almost any length, it looks like wood and combines all the positive attributes of the natural product with those of a modern composite material. Eslon Neo Lumber sleepers can be screwed together, nailed or sawn using conventional woodworking tools, and also adhere together superbly, achieving an even stronger bond than wood. Other positive features of the material include its low coefficient of linear thermal expansion and low thermal conductivity. Thanks to the closed-cell structure of the lightweight polyurethane-glass fiber compound, the sleepers absorb only a minimal amount of water. The fiber reinforcement provides the material with high compressive and tensile strength, making it one of today’s leading hightech construction materials. The material’s excellent resistance to hydrolysis, greases and oils is another quality which makes the “polyurethane wood” a very reliable material, even when exposed to long-term weathering. Unlike natural wood, Eslon Neo Lumber FFU loses none of its favorable mechanical properties, even after prolonged service in the open air. Being light in weigthand simple to process on site, it is also superior to concrete. Special techniques for installing sleepers are often required when working on old bridges. Moreover, the statics of these bridges normally mean that only lightweight materials can be used. In Japan, polyurethane sleepers are not only used on bridges but also on stretches that are frequently washed by seawater and exposed to an aggressive microclimate. In tunnels, due to the limited amount of space available, work is very difficult and costly, which is why in tunnels situated close to the sea, polyurethane, which is light and resistant to salt water, is generally preferred. Stable and weather-resistant alternative to wood Sleepers of varying length are used for the manufacture of points. When concrete sleepers are cast, a separate mold is needed for each length. With the pultrusion process, on the other hand, it is easy to make any individual length. Polyurethane sleepers are significantly lighter than concrete ones. This is a particular advantage with points sleepers, which can be up to 10 meters long. In addition, polyurethane sleepers do not break as easily as concrete ones. The excellent electrical insulation properties of the plastic sleepers is particularly effective in winter when the points have to be heated in order to prevent them from freezing solid. The material is also resistant to frost and deicing salt. For further information go to: www.sekisui.de
Page 1 and 2: Issue 1/2005 Baydur ® / Bayflex ®
Page 3: Baydur ®/Bayflex ® - Polyurethane
Page 7 and 8: Baydur ®/Bayflex ® - Polyurethane
Page 9 and 10: Bayer and its Partners BÜSING & FA
Page 11: Guide To Polyurethanes Fire protect

Here - Polyurethanes - Bayer

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?