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In this study, collagen hydrolyzate was obtained from bovine shaving wastes of leather production with the alkali hydrolysis reaction. Total amino acid, total carbon and total nitrogen amounts of liquid collagen hydrolyzate (CH) were determined. Fourier-transform infrared spectroscopy (FTIR) characterization of collagen hydrolyzate was performed. Obtained CH was emulsified with hydrogenated castor and amino functional silicone oils to prepare lubricating protein filler (LPF). Particle size and zeta potential of the LPF were analyzed. 10%, 15%, and 20% LPF was used in the retanning/fatliquoring process of chromium tanned bovine leathers. Performance characterizations of leathers treated with LPFs were carried out with tensile strength, tear strength, filling efficiency, light fastness, shrinkage, and denaturation temperature analyses. Moreover, bounded fat content in leather was also determined. Results showed the increased thermal stability, strength performance and good filling effect in leather by application of the prepared LPF. Consequently, LPF had a good potential as natural retanning/fatliquoring agent via achieving reuse of the solid leather wastes and providing satisfactory leather properties and cleaner production by one product itself.

The present study report on the attempts of synthesis of synthetic tanning agents based on different starting materials of phenol, urea, salicylic acid, resorcinol, dihydroxydiphenyl sulfone via condensation with formaldehyde. After many trials, best results were obtained from phenol-formaldehyde, phenol-ureaformaldehyde and dihydroxydiphenyl sulfone-formaldehyde systems. It was shown that the experiments with other starting materials need further investigations and more detailed studies for controlled reactions to obtain usable resins. The pH values and dry matter contents of the successful resins obtained from reactions were determined and the structural analysis was done by FTIR. Then the produced syntans were used as solo tanning agents for the tanning of pickled sheep skins. The results showed that all the leathers tanned with the synthesized syntans had shrinkage temperatures over 70 °C. Moreover, the filling coefficients of the produced syntans, the physical properties of the leathers in terms of tensile strength, percentage of elongation and tear strength were investigated. The produced syntans gave very white and/or light beiege colors with a good filling effect and plain grain structure. [ABSTRACT FROM AUTHOR]

In this study, collagen hydrolysate from bovine shaving wastes of leather production with the alkali hydrolysis reaction was emulsified with amino functional silicone oils to prepare lubricating natural polymer (LNP). Particle size and zeta potential of the LNP were measured. Prepared LNP was used in the fatliquoring step of chromium tanned bovine leathers. Contact angle of the leather surfaces with water were employed to study hydrophobicity of treated leather. The water absorption behavior of leather was determined by dynamic water resistance (penetrometer test) and static water resistance tests (kubelka water up-take). Performance characterizations of leathers were carried out with tensile strength, tear strength, filling efficiency and water vapour permeability (WVP) analyses. The contact angle measurements showed that the hydrophilic property of leather surface decreased after LNP treatment. Both dynamic and static water absorption behaviour was lowered while the WVP of leathers was not significantly affected negatively except of 20% LNP. Only 20% LNP application slightly decreased the WVP of leathers. Moreover, new lubricating agent provided satisfactory strength performance and good filling effect on leathers. [ABSTRACT FROM AUTHOR]