Aplicação e Caracterização de 14 diferentes productos de de engraxe

• Autor(a) principal: Ferreira, Vitor Ruben Moreira Pais
• Data de Publicação: 2018
• Tipo de documento: Relatório
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.22/16155
• topic: Leather; Fatliquoring; Staining tests; Particle size; Zeta potential; Couro; Engorduramento; Testes de tingimento; Tamanho de partícula; Potencial zeta

The leather making consists on converting a raw hide, a very putrescible material, into leather, a stable material, which is then used in the manufacture of a wide variety of products, ranging from shoes, clothing, leather goods, furniture, upholstery for cars, boats and aircraft, and many other items of daily use. These different applications however, require different types of leather. The final product is but the result of a complex sequence of chemical reactions and mechanical processes, being tanning the fundamental stage, since it gives to leather its stability, but it is the combining processes that in the end generate an article with very specific properties such as the appearance, temperature fastness, elasticity, softness among much more. Because of this is very important to understand the products that are used in this context, to achieve better performances and motivate the further improvements. The fatliquoring stage is a very important step in leather making, especially for achieving soft leather since there is, to a certain degree, a high demand for this property in almost any kind of hides. However, and contrary to popular belief, the main function of this process is not to bring in softness to the article but to effectively lubricate its fibers and avoid its resticking during the drying stage. The purpose of this study was to apply 14 commercially available products and characterize them physiochemically while also analysing the properties they confer to leather. With this objective in mind we made a complete characterization covering all the essential quality parameters that are used in the case of leather among them tear and tensile strength, fastness to light and temperature and of course softness and also studied the product characteristics using particle size distribution and zeta potential determination techniques, monitored the product performance along the application process and successfully optimized a technique to stain the neutral fraction of these products once inside the leather´s structure, pre and post drying. The size distribution and zeta potential determinations, overall achieved reliable results allowing to see the differences between these products as well as how these parameters influence certain characteristics specially regarding product penetration on leather. The staining of the anionic fraction of these products was already a currently used procedure but the staining of the neutral fraction was still rather untouched, and its method was successfully optimized and implemented. In terms of performance, these products achieved the expected results in most cases, and even surprised us positively in the case of the FF51 for example. The use of the chemical oxygen demand as a control parameter of exhaustion and product behavior along the process showed it can be very fast, practical and reliable possibly becoming a must in cases of product improvement, control and development. In terms of softness, all the products showed good properties, however the RTN PR165 and FF CL surprised with even better than anticipated.