Optimization of Leather Dyeing using Natural Dye Extract

Abstract- Consideration of environmentally friendly manufacturing process and product become indispensable issue due to increased environmental and health consciousness. In this regard many nations in the globe have stringent rules and regulations for industrial manufacturing and products to be safe both for environment and human health. Leather is animal skin widely used for footwear, garment, household and technical products. Leather products are colored with synthetic dyes of which, their processing have impact on environment and human health. Hence, the use of nonallergic and nontoxic natural dyes for leather coloration is a matter of significant importance as an option of dye source. The extract from the plant botanically called Osyris Quadripartita and Qerete locally used traditionally for leather dyeing in Ethiopia and other East Africa countries. In this research work, extracting and dyeing conditions were optimized to widen the application of the Osyris Quadripartita plant as a natural dye source for leather dyeing. Extraction was carried at variation of dye material concentration, extraction time and extraction temperature. The largest absorbance (A) value was obtained for dye extracted from 100 g/L dye material concentration, at boiling of 100oC for 60 minutes. Dyeing experiments were carried out with and without mordant. Pre and post mordant dyeing techniques were used. The dyed leather samples were analyzed for color strength (K/S), color difference (L* a* b* values) and color fastness properties. The highest color strength (K/S) value was obtained for leather sample dyed with post-mordant method using 2.5% of alum on weight of leather sample. The higher light fastness and rubbing fastness were obtained for leather samples dyed without mordant compared to mordant dyed leather samples. This implies that the extract from Osyris Quadripartita plant has a potential to be an alternative dye source for leather coloration.