Production and characterization of consisting nano ZnO fatliquoring emulsion and research on multifunctional leather production

First part of our thesis includes the pre-formulation studies for the production of lubricating paraffin emulsions containing nano zinc oxide. In the pre-formulation studies, the emulsifier proportions to be used on HLB determined for fatliquoring agents were selected from HLB scale. The effects of different parameters (pH, mixing speed, dosing of zinc oxide to emulsion, particle size of zinc oxide) on emulsions were evaluated. It was observed that the mixing speed had significant effect on the particle size of emulsions, however, the effect on the size of zinc oxide nanoparticles was negligible. The particle sizes of the prepared emulsions were compared with the particle sizes of commercial fatliquors used in the industry. Particle sizes of the produced nano zinc oxide paraffin emulsions were found to be proper to use in industry. The minimum zinc oxide concentration that was mentioned in the literature to have antibacterial effect was chosen as initial ratio. Produced fatliquoring emulsions were given to leathers during fatliquoring process and the antibacterial efficiency of leathers against E. coli were determined according to ASTM E2149-10 standard. The preliminary results showed that the antibacterial efficiency of the emulsions against test microorganism E. coli on the leathers was insufficient. Optimization studies of emulsion's active ingredient, fatliquoring percentage ratio in leather production recipe, pH values and particles size of emulsions were carried out on the purpose of increasing the antibacterial effect against test bacteria E. coli and determining the formulations of the main emulsions. In the second part of our study, the formulations determined after optimization studies were prepared with 6 different paraffin types under constant temperature. Wet-blue bovine hides were processed with the recipe for upholstery leather production. Prepared paraffin emulsions were applied during the fatliquoring process in the leather production recipe. Antibacterial efficiency of leathers against E. coli was determined with ASTM E2149-10 standard. The results showed that all paraffin emulsions produced in 3 different pH conditions gained bacteriostatic effect for leathers against test microorganism E. coli. However, SEM images of some leathers were taken. Third part of the study, physical properties of the leathers were determined. Tensile strength of the finished leathers (TS 4119 EN ISO 3376), single edge tear load (TS 4118-1 EN ISO 3377-2), double edge tear load (TS 4118-2 EN ISO 3377-2), stitch tear strength (TS 4138) and ball bursts (TS 4118-2 EN ISO 3377-2) of leathers were tested. The effect of paraffin emulsions containing nano zinc oxide on light fastness of leathers was examined according to EN ISO 105-B02 standard. Moreover, color measurements of the leathers processed with fatliquoring emulsions were put forward with Konica Minolta CM-3600d spectrophotometer. The leathers were subjected to accelerated ageing for 24h and 48h under 80 oC and UV in a cabinet (UV light of 254 nm) with temperature setting, and then discolouration of leathers under UV was provided. To make a comparison in the analyses, a leather sample without processing with the emulsion was subjected to ageing and compared with the other samples and effect of emulsions was carried out. After 24h and 48h ageing, how the color of each leather samples changed was examined in compliance with control sample. Also, shrinkage temperature was determined with IUP 16 to understand the effect of paraffin emulsions on hydrothermal stability of the produced leathers. The filling coefficient of the paraffin emulsions on the leathers was also checked. Analysis results showed that tensile and stitch tear strength values of the finished leathers processed with paraffin emulsions in fatliquoring were highly improved in comparison with the control group. The leathers treated with Paroil 1045 and Cloparten 330 paraffin emulsions provided the highest strength values. Most of the paraffin emulsions increased the single edge tear strength of the final leathers, but some of the emulsions were ineffective. It was determined that fatliquoring emulsions were not effective on double edge tear strength and ball burst of the leathers in general. Paraffin emulsions used in fatliquoring process improved the light fastness values according to control group samples. According to the hydrothermal stability results, used paraffin emulsions were increased the shrinkage temperature of the leathers in a high amount as 15 oC compared to the control group. Besides, prepared paraffin emulsions provided filling effect on the leather. In the fourth part of our study, dynamic water absorption of the leathers (TS 8541), static water absorption (TS 4123) and water vapour permeability (TS 4135) analyses were performed. When the results were examined, water absorption properties of the final leathers produced with paraffin emulsions in fatliquoring process significantly decreased compared to the control group samples. Hence, hydrophobicity ability of these leathers produced by paraffin emulsions increased, on the other hand, water vapour permeability values were negatively affected. The results obtained from the studies carried out with these kind of new generation fatliquoring emulsions containing nano zinc oxide were found to be highly promising in terms of using in leather industry.