Verfahren zur Verbindung der Sohle an den Schaft bei der Herstellung von Lederschuhen

Method consisting in treating the lasting (lit. mounting) margin of the shoe when mounted on its corresponding last with polyurethane polymers which react during the shoe fabrication process (between the stages of laying (lit. mounting) and of joining of the sole). These polymers crosslink by themselves or under the effect of catalysts within the leather, when heated or simply when kept for a certain period at room temperature; this crosslinking has the effect of strengthening their fibre structure and improving the cohesion between the layers of leather. As a result the operation of scouring and roughing is no longer necessary to be sure of adequate joining of the sole to the shoe upper. This method offers great advantages in that by eliminating the conventional operation of scouring or roughing it enables labour to be cut back, the process then being readily automatable; and the quality and appearance of the finished articles to be improved.