GUARANTEED COMFORT IN A HIGH-TECH SADDLE
15 June 2004 - Bayer MaterialScience AG

It also allows competitive cyclists to concentrate entirely on their racing. One of the leading manufacturers of products dedicated to the well-being of cyclists is the famous Italian firm, Selle Royal S.p.A., which specializes in saddles. The latest product to emerge from Pozzoleone, the company's headquarters, is the Lookin 3D saddle, which features a perfectly harmonized combination of three polyurethane materials for maximum comfort. In addition to the proven Royalgel® product, it also contains two layers of "traditional" and viscoelastic Bayflex® foam made from raw materials supplied by Bayer MaterialScience AG.

"To increase seat comfort, the most important thing is to reduce the contact pressure in the saddle as effectively as possible," says Dr. Andreas Hoffmann, a polyurethane expert with Bayer MaterialScience. "The introduction of the now established Royalgel® was a giant step forward in this respect compared with conventional foams, because it is able to distribute compressive stresses outstandingly well. When you put pressure on it, it feels soft and springy and then returns to its original shape immediately the pressure is removed. In the new Lookin 3D saddle from Selle Royal – the 'D' stands for 'Density' – this property is enhanced through an additional layer of viscoelastic polyurethane foam."

The trick is that, between the bottom layer of traditional Bayflex® polyurethane foam and the upper layer of Royalgel®, the 3D saddle has a so-called VEI, a "viscoelastic interface", which gives the gel more space to move around, not just in two dimensions but three. With the aid of this intermediate layer, the pressure is thus also dissipated very effectively to the lower regions of the saddle. According to Selle Royal, the Lookin 3D saddle reduces the pressure on the prostate gland, pubic bone and ischium by up to 80 percent.

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.

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