Browsing by Author "Wondimu, Wolde"

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    Manufacture of High-Performance Sheep Upper Leather From Low Quality Sheep Skins in Selection Through Process Upgradation and Optimization
    (Addis Ababa University, 2018-06-27) Wondimu, Wolde; Abubeker, Yimam (PhD); Aravindhan, R. (PhD)
    The quality of a raw material for any manufacturing industry or firm is one of the decisive factors controlling its productivity and profitability. Leather processing industries are no exceptions to this fact. The decline of quality raw material supply for the leather processing industries is a great challenge to be competent and survive in the industry these days. The quality of the raw material is largely affected by different factors. The problems leading to lower selection of raw skins or semi-processed skins in industry are categorized as ante-mortem and post-mortem defects. Especially the ante-mortem defect caused by ecto-parasite attack on the skins surface is one of the major problems for downgraded selection of sheep and goat skins. In this research work, an attempt has been made to upgrade poor and reject wet blue leathers due to mange disease damage or “Ekeke” on sheep skin. The problem of lower quality selection of skins could be improved and upgraded into better quality shoe upper leather by working on suitable leather processing techniques for covering the defects of mange damaged skins in wet-finishing and finishing by upgradation and optimization. In wet- finishing process, filler waxes and pigments combination were employed for upgradation. This has resulted in improved coverage of defects on dyed crust leathers. Physical strength tests and organoleptic property assessments performed on the treated leathers are found to be good. The optimized process of dyed crust leather is taken further for finishing, where five finishing methods were chosen for upgrading the uncovered defects in wetfinishing. Waxy, metallic, corrected grain and cationic finishing were employed against the conventional resin finishing. With cationic finishing, an improved and upgraded leather was obtained with better natural look or appearance of grain, good covering and comparable physical and organoleptic properties and better grade.