Rao, Rajahava (PhD)Shegaw, Ahmed (PhD)Bisrat, Tesfamichael2022-02-262023-11-282022-02-262023-11-282021-11http://etd.aau.edu.et/handle/12345678/30346Waterless Chrome Tanning Technology (WCTT) is a new technology in which the chrome tanning part of leather processing is carried out without water and with simple chemicals that insure excellent absorption of chromium by the hide thus avoiding the chrome waste water. but to bring the consumers (tanneries) to use this new technology in large scale we need to remove their fear and build their confidence in this new technology; one way of doing this is to have or show them a standardized process (post tanning). This research focuses on standardizing the post tanning operation for WCTT upper leather; different recipes were experimented with trial and error, but first to find if there is even a need to have a new post tanning recipe for the WCTT both conventional chrome tanned and WCTT were processed with the same conventional post tanning recipe, after that both the conventional chrome tanned and WCTT final crust leather were evaluated with organoleptic method and physical testing. The WCTT final crust made with conventional post tanning shows some lower organoleptic values, so to correct this, different post tanning trials were done, some of the trials were avoiding re chroming and checking the chrome oxide content, adjusting the neutralization by using different percentages of sodium bicarbonate and checking the pH of the leather, using different re tanning recipes, using neutralizing syntan in neutralization stage, on the dye part different percentage of dye is used and the best percentage is chosen based on the organoleptic result of the final leather and the final liquor color; also a trial of adding the dye in two batches to shorten the dye penetration time. The final leathers were assessed for fullness, roundness, grain smoothness, looseness, grain tightness, colour uniformity. Organoleptic properties or Functional properties of leathers in a scale of 0 – 10 points were rated by three experienced CLRI staff and average values were taken. Higher values indicate better properties. The physical properties such as tensile strength, water vapour permeability, water penetration, colour fastness, elongation at break were also done.en-USwaterless Chrome TanningPost tanningUpper LeatherThesis