Advanced technologies for split leather finishing15 October 2003
From 'waste' to a high-tech product, Bayer's Levacast system offers a variety of options for finishing splits and the splits that are produced during the horizontal separation of the hide during leather production are often mistaken for high-quality products. Leather specialists at Bayer Chemicals, a division of Bayer AG, have developed pioneering methods for turning split leather into articles with high value added. The products from the Levacast range enable very fashionable and heavy duty surfaces to be obtained, which cannot be distinguished from even the highest-quality fully grained leather. Virtually any surface structure can be reproduced - even exotic leathers. The particular advantage of this coating, which is polyurethane-based, is its high scratch and abrasion resistance. The mould process makes it possible to actually copy the leather surfaces. Using a 'natural leather' template with the desired structure, a mould is produced with the aid of liquid silicone that acts as a mould-making material. This release surface is first sprayed with an aqueous polyurethane dispersion and then dried. Levacast adduct and Levacast hardener are then applied using a two-component mixing and spraying head. The split is then immediately laid out over the mould and left to dry. After only a short drying time, the coated leather may be removed from the mould - which can be used again - and further processed For the most part, standard continuous release paper is used in production. Part of the coating is applied in one go to the release paper using a doctor blade. It is then dried. Afterwards the Levacast two-component system is applied and the leather laid out over the mould.