Desenvolupament d'un nou material col.Lagenic semi-processat

Resumen

The aim of the present work is to demonstrate the effciency of immersion tanning aplied to dehydrated bovine and ovine pelt, with the aim to generate a semi-processed collagenic material by means of dehydrating technologies based on the use of solvent. The production of the dehydrated material is made by a prototype that is expressely designed for this target, which isprepared to recover the solvent emissions. A series of experimental designs (screening) were made to define and optimize the dehydration processes to obtain dehydrated leather with the expected quality. The generated dehydrated material or collagenic material generat is characterised at physic and chemical level, and the interfibrilar spaces present in its internal structure were studied by means of porosimetry assays and SEM images; concluding that the material presents an internal porous structure. After that, a series of experimental designs were generated to define the working protocols for the immersion tanning of the dehydrated material. Once the dehydrated material from bovine and ovine origin were validated, a series of experimental designs were defined and elaborated in order to study exhaustively the reaction process between the chromium salts and the reactive groups of collagen applied by means of immersion technologies. The post-tanning and finishing technologies were applied by means of conventional formulations for footwear (bovine) and clothing (ovine) leather articles. Different lots of the above mentioned final leather articles were processed and evaluated in comparison with the quality requirements established for these kind of articles. Finally, the Doctoral thesis is completed by means of an environmental benchmarking to determine the chemicals, water and energy consumption in front of the conventional tanning processes. The final wastes were evaluated and compared with the quantities generated in the convenctional tanning. An economic and technical assesment were made to study the costs of new dehydrated leather processing; and consdiering the environmental and technical advantages of the dehydrated pelt in terms of semiprocessed materials, and water and chemicals offer reduction. In this way, the work developed is clearly focused to improve the competitiveness of leather sector by means of short-time new production lines for final leather articles due to the processing time reduction. This new technology will be usefull to substitute the conventional semi-processed leathers (which contains water and chemicals) by means of a new dried material able for long storing tome and quick response to the market. Future technical actions were defined to improve the energy consumption and solvent usage.