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Influence of Elastin Degradation on the Mechanical Properties of Leather 
by M. Schropfer, E. Kluver and M. Meyer
Volume: 109      Number: 9     Page: 306-313     Year: 2014
The influence of elastin degradation in leather on important mechanical properties was investigated. The elastin content of pelts and wet blues was determined by chromatographic analysis of desmosine, which is a specific and hydrolytically stable crosslinking. Analysis of pelts was performed directly, while chrome containing samples had to be detanned prior to analysis. It is demonstrated that elastase significantly reduces the elastin content. In contrast to often assured statements on the marked influence of elastase on softness, area yield, tensile strength and elongation of leather, our investigations showed no significant changes in the mechanical properties of leather as well as area yield, grain quality or softness after treatment with elastase. It is concluded that the impact of elastin on leather properties is generally lower than postulated before or that it is not pronounced in the dry state.
 
 
Carbon Footprint and Energy Balance of Biodiesel Produced from Tannery Fleshings 
by E. Kilic, R. Puig, G. Baquero and G. Zengin
Volume: 109      Number: 9     Page: 296-305     Year: 2014
This paper analyzes, from a life cycle perspective, the environmental performance of biodiesel obtained from leather industry fleshing waste (BDF). The indicators used for this environmental evaluation are: global warming potential (GWP) and energy return on investment (EROI). The contribution of each process-step in both GWP and EROI was determined. Transesterification of fat to obtain the BDF has been proved to be the most significant step in the process, mainly due to the consumption of methanol. A comparison between BDF and petroleum diesel obtained from non-renewable oil has also been performed using the same indicators. The results show a clear preference for BDF, although data from industrial real plants has to be considered in further works for BDF process to provide more accurate results.
 
 
Collagen and Keratin Colloid Systems with a Multifunctional Effect for Cosmetic and Technical Applications 
by J. Matyasovsky, J. Sedliacik, J. Matyasovsky Jr., P. Jurkovic and P. Duchovic
Volume: 109      Number: 9     Page: 284-295     Year: 2014
Fibril proteins of leather, mainly collagen, keratin, glycoproteins, hetero-polysaccharides as hyaluronic acid are the most significant from the view of application in cosmetics. Collagen is the most widespread animal protein component of skin, tendon, bones and ligament. Keratin is the main component of hair, fur, feathers, hooves, horns and outer surface of the skin. Keratin is characterized by a high content of sulfur amino acid cysteine with a typical formation of disulfide bridges. Modified collagen is the basis for several types of test colloids, where agents for the regeneration of the skin, with a high degree of its hydration appear very promising. Originality of the research was ensured as well by the biopolymer keratin as natural anti-solar protection of skin. This knowledge is based on physiological presence of keratinocytes in leather and connected protective mechanism against the effects of the sun. The aim of this work was to develop liposome colloid systems based on biopolymers with a multifunctional effect and to obtain higher benefit of cosmetic preparations e.g. increased hydration, regeneration, protection against ultraviolet radiation, barrier protection of the skin etc. and to ensure microbiologic stability of these systems by the application of colloid silver. Samples of biopolymers, dispersions, emulsions and liposomes were evaluated by the determination of their basic qualitative parameters as viscosity, dry content matter, size of particles and stability. Hydrolysates of keratin lower surface tension from the value ã = 72.8 mN.m-1 to the value approx. ã = 55.5 mN.m-1, and therefore, research was oriented to the possibility of lower dosing of synthetic emulsifier at keeping of required stability of hydrogels and hydro-creams. Results of testing samples confirmed increased hydration of the skin and protection mainly against UVB radiation. Evaluation of disinfectant efficiency of prepared colloidal silver confirmed the bactericidal, fungicidal and sporocidal effect against a broad spectrum of bacteria, fungi and microbes.
 
 
Solving Vein Marks Defects Problem through Wet End Process 
by K. Gowthaman, S. Vikram, N. Nishad Fathima and J. Raghava Rao
Volume: 109      Number: 9     Page: 278-283     Year: 2014
Leather grading is done on the basis of number of defects found on the leather. Defects either ante mortem or post mortem thus affect the final quality and price of the leather. In this study, we have investigated one of the ante mortem defects namely vein marks and have developed a process for upgrading leathers with this defect. SEM studies clearly depict the groove or indentation due to the vein marks. Upgradation using finishing often results in affecting the breathability of leathers. Hence, we have adopted a strategy of changing the post tanning recipe for upgradation of leathers with vein marks. The optimized post tanning recipe resulted in upper leathers with visibly reduced vein marks and the strength and organoleptic properties are on par with that of control leathers. Thus, this study shows that vein marks defect in leathers can be overcome by suitable post tanning process modifications.
 
 
Advances in Understanding of Enzymatic Unhairing of Bovine Hides 
by Marcelo Fraga de Sousa
Volume: 109      Number: 8     Page: 268-276     Year: 2014
The unhairing process is the most significant contributor to pollution load in the beamhouse. This has made unhairing one of most investigated areas over the past few decades, where the focus has been to reduce the amount of sulfur-based chemistry used during processing. In a country like Brazil, with 36 million hides processed every year, the amount of sodium sulfide applied during unhairing is around 10.800 tons/year, which represents approximately 2.200* ton of sulfur added to the process. A conventional unhairing process for bovine hides normally uses sulfide, sulfhydrate, lime, surfactants, and one or more auxiliaries based on mercaptans, thioglycolate, amines, urea, enzymes, or combination of these. The use of such auxiliaries was introduced many years ago with the purpose of reducing the amount of sulfide/sulfhydrate applied, while improving the efficiency of hair removal and helping to control swelling. Since then, many types of unhairing auxiliaries have come to the market, with different chemical compositions, for different purposes and with different efficiencies. Nevertheless, when the amount of sulfide/sulfhydrate needs to be reduced to very low levels without diminishing the quality of the unhairing and at reasonable cost, enzymatic auxiliaries are the preferred and logical choices. In this paper we will present the results from an enzymatic unhairing process developed by Buckman that allowed the reduction of Na2S offer to half of the normal levels. In addition to reducing the environmental impact of unhairing - and the whole beamhouse operation - the process also produced significant benefits in terms of increased area yield (from raw hide to wetblue), improved flatness, and less drawing while maintaining the same characteristics of grain integrity and tightness. * Considering 25kg/hide and an offer of 1.2% of commercial Na2S with 50% concentration.
 
 
Some Considerations about International Technical Coooperation in the Tanning Industry 
by Jakov Buljan
Volume: 109      Number: 8     Page: 248-260     Year: 2014
This was the 55th John Arthur Wilson Memorial Lecture presented at the 110th Annual Meeting of the ALCA. The abstract follows: Growth rates of the past and projections for the future point towards substantial livestock to support a strong tanning sector as well as towards an increasing gap between the raw hides and skins available and the assumed growing needs of the human population. The amount of pollution generated by the tanning industry is also significant. Taking into account the salt for curing, chemicals for processing and wastewater treatment, the ratio of chemicals used to fresh hide/skin weight is approx. 1:1. Furthermore, the major part of the chemicals added is actually not retained in leather; based on the present global input of approx. 10 million tons w.s. hide and skins weight the amount of process chemicals discharged into is of the order of some 7.0 million tons/year. Some 360 million m3of wastewater discharged/year contain about 1.8 million tons of COD, 1.2 million tons of Total Kjeldahl Nitrogen (TKN), 0.5 million tons of Cr, and, worst of all, more than 4.5 million tons of Total Dissolved Solids (TDS). Relocation of the substantial part of the tanning and downstream industry from North to South (the big shift) in recent decades also meant relocation of pollution for which developing countries were quite unprepared. Many of them have turned to United Nations Industrial Development Organization (UNIDO) for help. UNIDO is a specialized agency from the UN family, with headquarters in Vienna, Austria. Its mandate is to promote sustainable industrial development as an important driver of economic growth and thus contribute towards eradication of poverty. Sustainable development also incorporates the social and industry-related environmental and energy challenges. As of 1 January 2014, the Organization had 171 Member States and employed close to 700 staff at Headquarters and other established offices. UNIDO’s regular budget, covering staff and operating costs, is funded by contributions from its Member States assessed along the principles of the UN system, the largest contributor being Japan. Programs and projects are mainly funded through voluntary contributions from donor countries and institutions (the largest contributor is the EU), as well as from multilateral funds. External inputs are always are complemented by substantial local financing. Experience has shown that due to its inherent features multilateral cooperation is often more efficient and preferred over bilateral. Some typical projects developed and implemented by UNIDO Leather & Leather Products Unit tackling pollution prevention, wastewater treatment, finishing, occupational safety and health, gender equality, ecolabelling etc. In the last 30 years, UNIDO was to some extent involved in tackling up to 20 % of all tannery effluents generated in developing countries; its particular experience is in dealing with Common Effluent Treatment Plants (CETPs) servicing old or new tannery clusters. It is recognized that coagulation and flocculation as well as sludge conditioning before dewatering, crucial steps in wastewater treatment as performed today, would be impossible without the pioneering work on colloids by JA Wilson. Training tailored to the specific needs of recipients is an essential part of technology transfer. Modern means of communications offer fundamentally new possibilities of learning, especially for the young, “click & slide” generations. Five modules of the Animated Visual Training Tool (AVTT), supplementing the booklet Introduction to the treatment of tannery effluents have been made available for wider public use. A difficulty encountered in many projects was the (mis)perception that advanced cleaner technologies can limit end-of-pipe treatment to some simple and cheap procedures. A very special feature of UNIDO activities is its Leather and Leather Products Industry Panel, a global forum comprising some 20 reputable specialists from all walks of trade. The Panel’s primary function is to review and suggest the relevant topics and priority issues to be addressed by UNIDO TA. The latest paper produced for the Panel was the Carbon Footprint study for the leather industry, Shanghai 2012. UNIDO is traditionally a significant contributor to IULTCS/IUE documents and reference source for EU Best Available Technology (BREF) norms. Nowadays UNIDO assistance to the tanning industry remains that of a globally present catalyst focused on environmental issues but increasingly acting in the eWorld. The most pressing challenges confronted by the industry and the future of leather as material (e.g. durability vs. fashion changes/short-termism/consumerism) are also briefly discussed. Relocation of capacities in different directions in a globally free trade is a continuous process requiring high flexibility; the transfer North to South in both tanning and leather products is already being replaced by South-to-South movement. In any case, pollution prevention and treatment of waste remain the key ingredients of international technology transfer; eventually, it also helps leveling the competition ground. Ultimately, cooperation is much more than solidarity: development with all its spin off benefits (employment, education, better living standards, more balanced population growth etc.) is the conditio sine qua non for ensuring global stability.
 
 
Synthesis and Application of Novel Functional Material as Leather Flame Retardant 
by Bo Li, Jiaxun Li, Lixin Li, Xuanping Jiang and Zhengjun Li
Volume: 109      Number: 7     Page: 239-245     Year: 2014
A novel leather flame retardant was successfully synthesized from pentaerythritol, phosphorus oxychloride, melamine and tetrakis-hydroxymethyl phosphonium chloride (THPC) by three steps. Its structures and properties were characterized by FT-IR, elementary analysis, mass spectrometry, DSC and TG. It was applied to the manufacture of flame-retardant leather. The flame-retardant properties were investigated by the Limit Oxygen Index (LOI) test and Vertical Flame test. The effects of the flame retardant on physical-mechanical and handle properties of leather were evaluated at different conditions. The results show that this novel flame-retardant material can effectively inhibit leather burning, increase leather thermal stability and has effective flame retardant property. Furthermore, it has good synergistic effect for improving leather properties like fullness, softness, grain tightness, thus can meet requirements for leather flame-retardant technology.
 
 
Reuse of Solid Waste from Juice Industry (Citrus sinensis peel) in the Extraction of Antioxidants with Enhanced Activity through Polymer Encapsulates for the Preservation of Skin 
by M. Kumar, P. Velmurugan, K. Sreeram, J. Raghava Rao and B. Unni Nair
Volume: 109      Number: 7     Page: 231-238     Year: 2014
Bio resources are finding increasing applications in our day-to-day activities. Current research on the active ingredients of plant/fruit extracts has several applications. To widen their applications in various fields, suitable biocompatible carriers are needed which would increase the shelf life of the extracts. In this work, one such biocompatible carrier for encapsulation has been developed using PEG-Sodium alginate as a complex which will act as a model for any natural product extract viz., Citrus sinensis peel. The extract has been studied for its radical and nitrite scavenging activity, inhibition of â-carotene bleaching and lipid peroxidation assay, before and after encapsulation in order to quantify the antioxidant activity in presence of the carrier. From the experimental results, better encapsulation of the antioxidant have been observed with increasing molecular weight of PEG, up to 8000 Da which led to an increased shelf life and sustained release. Antioxidant-PEG-8000-SA, 20:2:1 (APS-8000) mixture has been optimized and used for preservation of goatskin. The dehydration, rehydration and hydroxyproline assays reveal that, APS-8000 would be better alternative for the conventional sodium chloride preservation.
 
 
Unique Rare Earth Pigments for More Thermally Comfortable Leathers 
by Sri Parasara Radhika, Gladstone Christopher Jayakumar, Kalarical Janardhanan Sreeram and Balachandran Unni Nair
Volume: 109      Number: 7     Page: 224-230     Year: 2014
This paper reports the investigations carried out on the synthesis characterization and optical properties of a new class of rare earth based near infrared reflective yellow pigments as an alternative to toxic inorganic pigments. The rare earth yellow pigments can be prepared by employing calcination method. The present work reveals that the doping of molybdenum for ceria in gadolinium cerium lattice changes the color hue from cream white to dark yellow. The calcination temperature employed for preparation of these pigments was about 1000°C. This temperature was found to be much lower than that required to achieve the intense yellow hue through conventional solid state calcinations reaction (above 1500°C). X-ray diffraction data confirm the crystalline character of the pigments. The pigment thus developed serves as a potential candidate for NIR reflective pigments for leather applications on account of its NIR reflectance value of 96% in the wavelength region 1100 nm. Thermal images of the finished leather exposed to NIR light clearly indicate the lower heat retention character. The pigment properties were in good agreement with industrial requirements. They also serve as environmentally safer pigments.
 
 
Green Solution for Salinity in Tannery Wastewater: A Step Forward in Leather Processing 
by S. Saravanabhavan, P. Velmurugan, J. Raghava Rao and B. Unni Nair
Volume: 109      Number: 7     Page: 214-223     Year: 2014
The conventional leather processing method contributes to high salinity in wastewater due to the discharge of enormous amount of salts used for preservation. Hence, an attempt has been made to replace the salt with polyethylene glycol (PEG) to reduce the salinity in tannery wastewater. The molecular weight (MW) and percentage offer of PEG were standardized based on the rate of dehydration of hide matrix during preservation and rehydration of preserved hide matrix. The determination of hydroxyproline in spent soak liquors at various time periods during storage showed that the preservation of hides using PEG MW 2000 was more effective than sodium chloride. The reduction in total salinity by 43% is possible in tannery wastewater through PEG based preservation of raw hides. Functional characteristics of the experimental crust leathers are shown to be on par with control crust leathers. The developed greener process appears to be technically viable and economically acceptable alternative for salt based preservation.