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Leather with "desirable qualities"

November 27, 2002

According to the German leather industry association VDL, "The art of dressing leather lies in the ability to apply the finest possible protective coating without detracting from its natural appearance or impairing desirable qualities such as suppleness and breathability." In other words: The secret of leather finishing is to ensure that the customer doesn't notice the difference. Evidently, the thickness of a layer of applied material varies from one substance to another, but once it exceeds 0.15 millimeters experts refer to the process as "coating" rather than "dressing". For them, the "desirable qualities" of leather have long since been defined in the form of industrial standards, such as: interlaminar strength, rubbing fastness of the upper surface, wear resistance, water spotting fastness, moisture-vapor transmission and absorption, fogging (the evaporation of volatile substances), heat resistance and light-fastness.

New finishing treatments elaborated by the Fraunhofer Institute for Silicate Research ISC in conjunction with a commercial research institute in Freiberg (Forschungsinstitut für Leder- und Kunststoffbahnen GmbH, FILK) produce results on upholstery leather that meet all requirements of the latest standards. "In some respects, they are even far superior," proclaims project manager Dr. Sabine Amberg-Schwab. "Nevertheless, the individual technical parameters should not be judged in isolation, for it is the overall combination of properties that make ORMOCER®-treated leather an interesting proposition for furniture, shoe and clothing manufacturers." These inorganic-organic hybrid polymers have already demonstrated their usefulness in many applications. A patent application for their use in the finishing treatment of leather was filed earlier this year.

"One of the main advantages with respect to more conventional finishing treatments is the material's behavior in contact with moisture," stresses Amberg-Schwab. "Looking at just one characteristic, namely water spotting fastness, or the time a drop of water remains on the surface of the leather before being absorbed: Industry requires a value of at least ten minutes - we can achieve over half an hour!" At the same time, ORMOCER® coatings on leather have a comparatively high moisture-vapor transmission. The coatings can be modified to suit different applications, leading to the creation of completely new sets of properties. After all, you can't compare a handbag with a biking jacket or a shoe with a sofa.

Fraunhofer-Gesellschaft