Reduction of Yellowing Effect on Leathers with UV Absorber Benzophenone-4

Abstract

Besides quality in leather manufacture, another important factor is that the customer should use the product in the long term without any problem. However, a leather product, being a natural structure, can age because of environmental conditions such as UV, temperature, and humidity, and its chemical and physical structure can change with time. Some leather products in particular such as upholstery leathers which are exposed to sunlight can be aged and yellowed by the effects of UV light and temperature. Therefore, there is a need to prevent ageing and yellowing. UV absorbers are often used in various products such as cosmetics and polymeric materials to prevent the destructive effects of ultraviolet radiation. The aim of this work was to study use of the UV absorber benzophenone-4 in reducing yellowing. Chrome-tanned and vegetable-tanned crust leathers were given a coating of hydro lacquer [lacquer emulsion] including the UV absorber benzophenone-4 as a finishing process. After exposure to monochromatic UV light at a wavelength of 340nm for 24, 48, 72, 96, 120, 144 or 168 hours at approximately 80 degrees C. The results were investigated by CIE Lab Colour measurement and by FTIR-ATR spectrophotometer.