Economical production thanks to polyurethane

Economical production of the soft saddle is made easier by the properties of the polyurethane. In order to permanently join together the three saddle layers, it is enough to inject them one after the other into an open mould, in the same way as in shoe sole production. "Since polyurethanes adhere to a wide variety of other materials in their raw state - particularly well, of course, to other polyurethane systems - we were able to dispense with the complicated bonding processes for building up the layers," says Hoffmann. This also applies to joining on the polypropylene half-shell, which stabilizes the flexible layers in the saddle, and the PVC film, which gives the finished product its abrasion-resistant surface. When the mold is closed, both are joined permanently to the 'innards' of the saddle by the reacting polyurethane. The total cycle time for manufacturing this comfortable polyurethane saddle is just a few minutes.
"During the development work, especially when it came to coordinating the three polyurethane components, the Bayer MaterialScience specialists were able to give the experts at Selle Royal plenty of technical support," says Hoffmann. Because the new high-tech saddle was to have "windows" to show its complex structure, it was important, for example, to use particularly colorfast raw materials for the Royalgel® layer. The newly developed viscoelastic polyurethane foam in the “VEI” also had to comply not only with the strict comfort specifications, it also (like the lower foam layer) had to guarantee absolutely bubble-free, void-free expansion. In addition, it had to meet the stringent adhesion requirements - even under the high shear loads to which the inside and surface of the saddle are subjected during its service life. "All in all, together with our colleagues at Selle Royal, we spent several months optimizing these technical details. For our partners in the polyurethane-processing industry, this kind of service is an important bonus, and often gives us a vital lead over our competitors," says Hoffmann.

Leverkusen, 2004-07-26