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Öğe Eco-leather: Chromium-free leather production using titanium, oligomeric melamine- formaldehyde resin, and resorcinol tanning agents and the properties of the resulting leathers [Eko-deri: Titanyum, oligomerik melamin formaldehit reçinesi ve rezorsinol tabaklama maddeleri ile kromsuz deri üretimi ve elde edilen derilerin Özellikleri](2012) Adiguzel Zengin A.C.; Crudu M.; Maier S.S.; Deselnicu V.; Albu L.; Gulumser G.; Bitlisli B.O.; Basaran B.; Mutlu M.M.The chromium salt tanning system, which is still the most popular leather tanning procedure, is under continuous pressure from environmental groups and international regulations. Therefore, for many years, numerous experiments have been carried out on chromium-free leather production. In this study, newly produced synthetic and inorganic chemicals were used as tanning and pre-tanning agents as an alternative to a chromium tanning agent. This new titanium based tanning agent, obtained from processing wastes from the industry of nonferrous metals, was used as a main tanning agent. In addition, an oligomeric melamine-formaldehyde resin and resorcinol type pre-polymer were used as pre-tanning agents for the production of chromium-free leathers. Physical tests and chemical analysis of the produced chromium-free leathers gave comparable results to leathers tanned with basic chromium sulphate.Öğe Eco-leather: Properties of chromium-free leathers produced with titanium tanning materials obtained from the wastes of the metal industry [Eko-deri: Metal Endüstrisi Ati{dotless}klari{dotless}ndan elde edilen titanyum tabaklama maddesi ile üretilen kromsuz deri örneklerinin özellikleri](Cevkor Vakfi, 2014) Mutlu M.M.; Crudu M.; Maier S.S.; Deselnicu D.; Albu L.; Gulumser G.; Bitlisli B.O.; Basaran B.; Tosun C.C.; Adiguzel Zengin A.C.In this research, a new titanium tanning agent (TMW/2) obtained from the wastes of the metal industry was investigated in the production of chromium free eco-leather, by experimenting with various amounts of tanning agent and comparing the physical and chemical properties of the tanned leathers. The tanning process was performed with different concentrations of active titanium tanning material such as 1%, 2.5%, 5%, 7.5%, and 10%. The titanium content, chromium oxide content, formaldehyde content, shrinkage temperature, pH value, ash content, and fat content of the tanned leathers were investigated for the determination of chemical characterization. The tensile strength, elongation at break, tear strength, and colour measurement tests were also carried out for investigating the physical properties. The titanium tanned leathers had a mean shrinkage temperature of 79.5°C and more yellowish colour than the chromium tanned leathers. Their tensile strength properties were found similar with chromium leathers, while the elongation at break was found to be lower and tearing resistance was higher. The usage amount of 2.5% could be perfectly advised for the tanning process based on the titanium tanning material for achieving optimal properties required from different leather types such as upholstery, automotive and shoe upper leathers. Consequently, our results showed that this new titanium tanning agent could be used as an alternative tanning material in the production of chromium free eco-leathers considering the visual, physical, and chemical properties of resultant leathers.Öğe Evaluation of natural dyeing of leather with Rubia tinctorum extract [Derinin Rubia tinctorum ekstrakti{dotless} ile dogal boyanabilirliginin degerlendirilmesi](2011) Onem E.; Gulumser G.; Ocak B.The aspect of producing leather and textile products without impacting on the ecological balance, affecting both human and environmental health, is an important focal point to be pursued. Therefore, to address some of these issues a study was conducted to evaluate the efficiency of dyeing leather with madder, which is a 100% natural dyestuff from the extract of Rubia tinctorum and ascertain its friendly attributes to the environment. Treatment designs in the study included pre and post mordanting methods which were applied to selected types of leather and subsequently subjected to three different mordants: potassium aluminium sulphate [KAI(SO 4) 2.12H 2O], copper sulphate [CuSO 4.5H 2O] and ferro sulphate [FeSO 4.7H 2O]. This approach was done to potentially obtain different colors and improve color fastnesses. In this study, the investigation was based on two primary source of tanned material, chrome and vegetable tanned leathers. Color measurements of the dyed leathers were carried out using a Minolta CM-508d brand spectrophotometer. On the other hand, dyestuff exhaustions were determined using a Shimadzu UV-1601 PC UV-Visible spectrophotometer. On the finished leather products, parameters such as color fastness to rubbing was determined with, the TS EN ISO 11640, color fastness to perspiration with, the TS EN ISO 11641, and color fastness to light with, the ISO 105-B02 standard method. Moreover these parameters were comparatively analyzed and reported. The results eventually indicated that the obtained color and color fastness values varied according to; the type of tanning method, mordanting method, and mordant type. Most of the result values obtained were generally at satisfactory levels which were between 3/4 and 5 fastness values. Different extraction methods, different mordants, and mordanting methods to be carried out in future are suggested so as to optimize the results of the current study.Öğe High pressure vegetable tanning of sheepskins using supercritical carbon dioxide(Elsevier B.V., 2015) Onem E.; Gulumser G.; Renner M.; Yesil-Celiktas O.Leather is a porous material composed of a three-dimensional weave of collagen fiber bundles. The high pressure tanning (HPT) of sheepskins with valonea tannin in supercritical CO2 was approached to investigate the diffusion process through the skin matrix. Uptake of vegetable tanning agent (VTA) was analyzed at 100 bar and 32 °C with varying tanning times (2–8 h). Shrinkage temperature (Ts) as thermal stability of the tanned collagen and filling coefficient (%) of pressurized vegetable tanning (PVT) were also analyzed. The best results were obtained at 8 h treatment yielding 83.77% of VTA uptake and a filling coefficient of 54.97%. PVT experiments showed a satisfactory conversion of the skins to leather in terms of the thermal stability. Scanning electron microscopy (SEM) of the tanned skins showed that high pressure did not alter the fiber structure and morphology negatively. The proposed technique has high potential to be deployed to industrial scale. © 2015 Elsevier B.V.Öğe New tanning agents based on titanium and zirconium(2010) Crudu M.; Deselnicu V.; Mutlu M.M.; Gulumser G.; Bitlisli B.O.; Basaran B.; Zengin A.C.A.This paper presents the study of new solid complexes of Ti(IV) and Zr(IV) derived from the interaction of TiOSO4·2H2O and ZrOCl2·8H2O with C4H5NO 3 (n-hydroxysuccinimide) in central atom:ligand combination ratio of 1:1 and 1:2. To characterize the new compounds in solid state, specific methods have been used: infrared spectrometry, X-ray diffraction, thermodynamic analysis to establish the structure and possibilities of use in leather processing. It has been established that Ti(IV) complexes make up structures by hexacoordination and Zr(IV) makes up dodecahedral structures.Öğe Oligomeric melamine-formaldehyde resin as pre-tanning agent(2010) Pruneanu M.; Maier S.S.; Maier V.; Deselnicu V.; Mutlu M.M.; Gulumser G.; Bitlisli B.O.; Basaran B.; Zengin A.C.A.This paper presents a novel procedure for the chemical synthesis of a melamine-formaldehyde resin, modified by sulfonation with sulfanilic acid. The product was characterized by chemical analysis, FTIR spectroscopy and gel-permeation chromatography (GPC). Experimental data confirmed the obtaining of three oligomeric fractions of the melamine-formaldehyde polycondensate class, with potential uses as pretanning agent in the manufacture of bovine wetwhite leather. The tanning potential of the obtained resin was assessed through the shrinking temperature of the tanned bovine pelt. An increase of the shrinking temperature by 8-10°C was recorded on the pretanned leather, compared with the pelt, when the resin was used alone, while when used along with resorcine, an increase by 30°C of the shrinking temperature was recorded.Öğe Properties of leathers tanned with ti-al based tanning materials obtained from the wastes of metal industry(2012) Mutlu M.M.; Zengin A.C.A.; Crudu M.; Maier S.S.; Deselnicu V.; Albu L.; Gulumser G.; Bitlisli B.O.; Başaran B.; Tosun C.C.Although chromium tanning is the most popular tanning system worldwide, it is held under the microscope due to increasing requirements on disposal of chromium tanning effluents, by-products and sludge. For this reason; in last decades, researches on alternative tanning materials which will decrease or replace chromium usage take a great share among the main topics in the area of leather researches. In this research, a newly produced titanium based tanning agent, obtained from processing wastes from the industry of nonferrous metals was used as an alternative to chromium tanning agent. The new titanium tanning agent was experimented with 1%, 2.5%, 5%, 7.5 and 10% dosages. Physical tests and chemical analysis of the produced chromium-free leathers gave comparable results to leathers tanned with basic chromium sulphate. 5% usage of titanium tanning agent was found to be optimal.
