Utilization of Tannins Extract of Acacia seyal Bark (Taleh) in Tannage ofLeather

摘要

Leather is a durable and flexible material created by the tanning of animal raw hide and skin, primarily cattle hide and natural grain, variation in the grains, good breathability and other natural features are all signs that the material is genuine. The most commonly used tanning methods are chrome and vegetable tanning. The vegetable tannins are extracted by using a suitable solvent, usually water followed by concentration and spray drying to get powder or solid. The tanneries in the Sudan imported mimosa and synthetic (syntan) tannins material for the process of retanning and pretanning. This study was undertaken to utilize Taleh bark (Acacia seyal Bark) as a retanning material for production of upper and garment leathers. The tannins content of Taleh bark was found to be 28.9% and therefore it was promising and would successfully be used as retaining and tanning materials. In this study; the factors that affect leaching which are mainly time, solvent to solid ratio, temperature, agitator speed and time of extraction. A two - level factorial experiments were designed and the level of the above factors was determined according to the statistical analysis. It was found that a solvent solid ratio of 6:1, speed of agitation of 250 rpm, temperature of 30°C and time 2 hours were the optimum conditions. A complete design of a long tube triple-effect evaporator is made for production of 1000 tons per year which is enough for the present level of capacities in the tanneries to date. In conclusion it is clear that Sudan can produce tannins extract from Taleh bark which can be used for pretannage, tannage and retannage. It is recommended that the Taleh bark and similar Acacia seyal can be analyzed and leached to give tannins powder extract to replace imported Mimosa extract.