Under the product name "Rotapur", FKM processes different polyurethane systems such as polyester-, polyether-or polycarbonate-polyurethane to make roll coverings. The name hints at the rotational moulding which is used for manufacturing. In this process, the liquid PU system is poured directly onto the turning roll cores. A jet runs down the length of the roll body so that an even, continuous layer is formed. This procedure is made possible through a highly accelerated chemical reaction which means that the material hardens instantly and does not drip.
The advantages are clear: casting moulds are no longer required, the covering can be made up of different kinds of layers and the bearing usually does not have to be dismounted as the rolls do not need to be tempered afterwards.
Different chemical systems can be used to adapt the coverings for particular application conditions: they are resistant to demanding mechanical, thermal or chemical conditions. Our PU rolls have a suitably varied range of possible applications:
For light weight rolls, the PU covering is applied to a roll body made of fibre composite. Due to their low weight, these rolls can also be built into areas which are difficult to reach without any trouble. At the same time, the small mass moment of inertia allows strong acceleration without slipping and with a low amount of wear and tear. For this reason, FKM light weight rolls are often used as support rolls in horizontal buffers in pickling lines in the steel industry or as deflection rolls in vertical buffers for copper strips with sensitive surfaces.
This is how our PU rolls are made.