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In leather production the chrome tanning method is the most widely used tanning system all over the world despite the storage and disposal of solid wastes and sludge containing high amounts of chromium poses a major challenge. For this reason many researches based on higher exhausting and lower chromium used technologies have emerged in the recent past. However, these technologies are not directly accepted by the industry due to risks and some possible changes in quality issues. Accordingly, in this project one of these approaches: chromium tanning without pickling process, using less chromium salts at higher initial pH is tried in pilot scale at a leading company in Turkish leather industry. The variables used in the research were; pre-tanning agents (aldehyde, sulphonyl chloride, and synthetic tanning agent), initial pH of tanning (5.0-5.5 and 6.0-6.5) and tanning agents (standard basic chromium sulphate and commercial tanning agent with lower chromium oxide content). The wet-end processes and finishing processes of the leathers were applied according to the company's production line. Chromium content of the leathers and the Cr2O3 remaining in effluents were determined for each tanning application. Also, the physical properties of the leathers were investigated. The Cr2O3 of the leathers were found to be varying between 3.12-4.83% while the remaining chromium in the effluents was between 16.9 -1347 mg/L. Additionally, the properties of the final leathers were evaluated comparatively with company's regular products, considering the test results and organoleptical evaluations it was concluded that many of them were comparable to conventional chromium tanned regular products.

In this study, it was aimed to comparatively investigate the grain properties of shoe upper leathers produced for different purposes. Thus, six different types of shoe upper leather (cracked, antique, patent, nappa, nubuck, printed) were provided from three different footwear companies. The tensile strength and elongation at break (TS EN ISO 3376), single and double edge tear strength (TS EN ISO 3377-1, TS EN ISO 3377-2), cracking and bursting resistance (TS 4137 EN ISO 3378, TS EN ISO 3379), flex resistance (TS EN ISO 5402-1) as well as dry and wet rubbing fastness tests (TS EN ISO 11640) were applied to leathers that have similar thicknesses. The results of the study gave information about the physical strength and product performances of different upper leather types. The data were evaluated comparatively and the effects of shoe upper leather types on quality and performance were evaluated.

Chromium tanning using less chromium salts at higher initial pH values is one of the approaches offered in recent years in order to overcome environmental problems caused by conventional chromium tanning. However this system couldn't be directly switched to application due to its potential risks. In the present study this ecological approach was investigated at industrial scale. The variables used in the research were: pre-tanning agents, initial pH of tanning and tanning agents. Various wet-end and finishing processes depending on three different types of products were applied according to the company's production line. Chromium contents of the leathers and remaining amounts in effluents were determined for each trial. Also, the physical properties of the leathers were investigated. Along with maintaining similar properties and quality from the produced leathers, chromium remaining in residual baths could be reduced up to 92 and 76% by alternative formulations respectively in 500 kg and 6000 kg batches. KEY WORDS: leather, chromium tannage, high exhaustion PRACTICI PRIVIND SISTEMUL DE TĂBĂCIRE ECOLOGICĂ ÎN CROM REZUMAT. Tăbăcirea în crom care utilizează mai puţine săruri de crom la valori iniţiale mai ridicate ale pH-ului este una din abordările apărute în ultimii ani pentru a rezolva problemele de mediu cauzate de tăbăcirea convenţională în crom. Cu toate acestea, acest sistem nu a putut fi pus în aplicare în mod direct din cauza potenţialelor riscuri. În studiul de faţă această abordare ecologică a fost investigată la scară industrială. Variabilele utilizate în cercetare au fost: agenţi de pre-tăbăcire, pH iniţial al tăbăcirii şi agenţilor de tăbăcire. Au fost aplicate diferite procedee umede şi finisaje în funcţie de trei tipuri diferite de produse, conform liniei de producţie a companiei. Conţinutul de crom din piele şi cantităţile rămase în efluenţi au fost determinate pentru fiecare încercare. De asemenea, au fost investigate proprietăţile fizice ale pielii. Pe lângă menţinerea unor proprietăţi şi a calităţii pielii fabricate, cromul rămas în flotele reziduale ar putea fi redus până la 92 şi 76% prin recepturi alternative, în loturi de 500 kg, respectiv de 6000 kg. CUVINTE CHEIE: piele, tăbăcire în crom, epuizare mare PRATIQUES SUR LE SYSTÈME DE TANNAGE ÉCOLOGIQUE AU CHROME RÉSUMÉ. Le tannage au chrome utilisant moins de sels de chrome à des pH initiaux plus élevés, est l'une des approches proposées ces dernières années pour surmonter les problèmes environnementaux causés par le tannage au chrome conventionnel. Cependant, ce système ne pouvait pas être directement transféré à l'application en raison de ses risques potentiels. Dans la présente étude, cette approche écologique a été étudiée à l'échelle industrielle. Les variables utilisées dans la recherche étaient: agents de prétannage, pH initial du tannage et des agents de tannage. Différents procédés par voie humide et de finition ont été appliqués avec trois types de produits différents, en fonction de la chaîne de production de l'entreprise. Les teneur...

Chromium tanning is a matter of high concern due to chromium containing effluents and wastes. More ecologic systems with less chromium usage or chrome-free production systems are subject of studies in recent years. One of the approaches in this concern is to use non-pickling systems and higher initial pH to increase exhaustion in chromium tanning. However adopting this system in leather industry has some challenges like to assure the same quality. In a project with one of the leading companies in Turkish Leather Industry, higher exhausting chromium tanning system has been planned to be tried in laboratory, pilot and industrial scales respectively with various pH and pre-tanning agent parameter changes. In the present stage (pilot scale trials) of the project, best resulting formulations from the laboratory scale trials were carried out to pilot scale (500kg batches) by expanding the trials with additional pre-tanning agents. From the results, it was seen that chromium remaining in the baths were varying between 325-875 mg/L. Which means amount of chromium remaining in residual baths could be reduced up to 78.87 % to 92.15% comparing to conventional tanning while 2.9-4.7% of Cr2O3 bound to the leathers depending on the type of system used in pilot scale trials.