Acrylic resins have affinity for chrome tanned leather, for this reason, they are widely used as a retanning products. Its main use as a retanning agents is to produce full leathers. However, the leathers retanned with them have lower colour intensity and poorer structural properties because of their high anionicity which change the cationic surface of the leather causing a lower interaction of dyeing and fatliquoring agents with leather. This study proposes the use of modified polyacrylates as a new retanning agents. They were applied in leather versus traditional acrylic resins. The properties of the retanned leathers were evaluated concluding that this type of resins improve some leather properties avoiding the dyeing and fatliquoring problems of the traditional acrylic resins. The structure and the molecular weight of the modified polyacrylates play an interesting role in the improvement of the fixation of dyes and fatliquors, but also its lower anionic charge in comparison to the traditional acrylic resins. It has been observed that final leathers have a better colour intensity and softness. Moreover, its use as retanning agents favours the absorption of dyes and fatliquors which means an environmental improvement for the wet end process.

Content: The original substance of a book binding provides information about the place of origin, storage and user history of the book, why the preservation of this material in its original form is of crucial importance for research in the field of bookbinding. In a current research project in cooperation with FILK Freiberg, a newly sustainable treatment for historical aged leather book covers will be developed. The aim is to introduce a long-term mild care agent to boost leather flexibility, which will remain in the structure and to stabilize the pH value at the optimal level with the buffer introduced in the form of deacidification agent. Preliminary research showed, that ageing processes of vegetable tanned calf leather, which has been mainly used for leather book bindings in the past centuries, haven’t been fully explored yet. Further, essential characterization methods like the determination of the acid content and methods for accelerated aging tests are not yet defined for leather. For a systematic development and evaluation of the newly treatment, the project had to be focused on these topics first. Oxidation and acid-catalyzed hydrolysis have an enormous impact on the state of the leather. Both take place simultaneously and affect each other. It could be shown that the damage by acid hydrolysis is much more dominant than the damage by oxidation. Since oxidation plays only a minor role and can be slowed down only preventively by storage conditions, the project focused on the hydrolysis as the significant degradation mechanism. The aim of accelerated ageing was to reproduce as precisely as possible observed and identified degradation mechanisms in the natural aged leather. Therefore, a two-step aging process has been developed. The first stage is to introduce the acid into the material that is to be used to simulate the acid catalyzed hydrolytic degradation. The second step is to verify the effectiveness of the newly developed care products by comparing treated and untreated leathers at this stage of aging. The aging was evaluated by optical / haptic tests, shrinking temperature, mechanical properties, hot water solubility, pH value and differential number. Regarding the leather characterization, the determination of the exact amount of acid introduced by the artificial aging is of great importance for the development of the aging method as well as for the pH adjustment of the leather. For the method development, an acid-base titration was selected, which allows quantitative results of the acid content in the examined material. The developed method is easy to carry out and allows the measurements of different sample quantities (0,1 g - 1,0 g). Take-Away: - acid-catalyzed hydrolysis is the dominant degradation mechanism, oxidation plays a minor role - acid-base tritration allows quantitative results of the acid content in the examined material - development of an accelerated ageing method

Content: Sustainability and transparency of the leather industry are increasingly important factors for the sector’s clients as well as final consumers, looking for quality products that are also sustainable in all tiers of the production process. In this sense, certification and labelling processes are tools that grant visibility to the positive practices of manufacturers and their suppliers. In Brazil, through an unprecedented tanneries initiative conducted by the Centre for the Brazilian Tanning Industry (CICB), a certification for the leather production process was created. The Brazilian Leather Certification of Sustainability (CSCB) counts on the participation of the various links in the production chain. Using the concept of the sustainability tripod, CSCB considers the results of tanneries in economic, environmental and social aspects. A sustainable tannery develops its activities with positive economic results, seeking to reduce inherent environmental impact of its activities, providing better working conditions to employees and respecting the surrounding community. Since the starting point of its creation (2012), CSCB has reached many results concerning process’ improvements in the industry, quitting wastage and getting efficiency in indicators. As the CSCB practices are inside more than 20 tanneries all over Brazil (some of them amongst the biggest in the country, covering a big part of the Brazilian leather production, which is one the hugest in the world) these findings are extremely important and must be shared with whole industry. The certification process is based on implementation and compliance with principles, criteria, and indicators established by standards developed by the Brazilian Association of Technical Standards (ABNT) and audited by certification institutes accredited by The National Metrology, Quality, and Technology Institute (Inmetro), signatory to the mutual recognition agreement within the framework of the International Accreditation Forum (IAF) and the International Laboratory Accreditation Cooperation (ILAC). These agreements guarantee the international validation and recognition of CSCB. Tanneries are certified according to how well they meet the standards, being granted an identification seal for sustainable processes, guaranteeing the transparency of Brazilian leather suppliers. Take-Away: Sustainability as a tool for efficiency in the leather industry Results on the last years of work of the Brazilian Leather Certification of Sustainability (CSCB) Sustainability indicators on Brazilian tannery work

Content: Air temperature and humidity are fundamental in the milling operation. There is a complicated correlation between air conditions and leather moisture that is practically impossible to predict in industrial process. Many important characteristics like softness, grain, pebble, yield depend on leather moisture. This patented system is the latest improvement in milling drums technology that keeps the leather cooler and allows a precise and optimal humidity control. Designed for soft, tight-grained leathers, especially from organic tannages and opened to a wide range of new operating conditions impossible with traditional machinery. The original new design makes the milling drum completely independent from the outside environment with many advantages: consistency over seasons, shorter transition time, energy savings. The original design is recognized by international patent, laboratory results on leather will be displayed during the presentation. Take-Away: The original new Cold Milling technology design makes the milling drum completely independent from the outside environment with many advantages: consistency over seasons, shorter transition time, energy savings. Nappa leather and all tight-grained leathers, especially organic tannaed, are beneficiary of this new technology.

Content: Animal skins, a byproduct of the meat industry is the basic raw materials for the tanning industry. Just after flaying, animal skins have to preserve protecting it from microbiological destruction. Globally, sodium chloride is mostly used as popular preserving agents for the animal skins. It preserves the skin by its dehydrating ability. Nevertheless, sodium chloride is cost-effective, available, and easy to apply but the method suffers greatly in terms of environmental context. To reduce the pollution load, especially chloride in soaking operation several works have been carried out to preserve animal skins with various agents. This study is intended to preserve the goat skin with Sphagneticola trilobata leaf paste without sodium chloride for reducing the chloride in the soaking liquor. The plant has antimicrobial activity, widely distributed tropical and subtropical regions. The anticipated preservation method was assessed monitoring different parameters e.g., shrinkage temperature, hair slip, putrefaction, odour, moisture content, extractable nitrogen, and bacterial count on fresh (raw), 1st, 4th, 7th, 14th, 21st and 28th day in comparison to the conventional wet salting method. The physical properties of the processed leathers e.g., tensile strength, percentage of elongation, and ball burst of the crust leathers were fulfilled the required values. The chemical parameters like chloride, total dissolved solids (TDS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) of soaking liquor were investigated. The proposed preservation method was reduced pollution loads: chloride, TDS, BOD, and COD in soaking operation by 98.04%, 92.9%, 90.2% and 85.5%, respectively. The scanning electron microscope (SEM) photographs of both the present and conventional preservation methods processed crust leathers revealed similar texture and quality to each other. The anticipated preservation method could be a sustainable option to preserve goat skin, which could reduce the pollution loads during leather processing. Take-Away: 1. Sphagneticola trilobata leaf paste preserved goat skin up to 28 days 2. Reduction of chloride and TDS were 98.04% and 92.9% in soaking liquor 3. Lessening of BOD and COD were 90.2% and 85.5% in soaking liquor

Content: We are a group company of a major department store in Japan. We are in charge of quality control and customer service of items sold by our stores. We constantly monitor our customers’ concerns, and we have been keeping customer correspondence records since 1996. We hold over 100,000 cases for all items of food, clothing, living and services. The record includes not only customer requests but also test results of each item before sales as well as reproduction test results based on customer requests. We use the database to build our quality standards for everything we sell and for the education of our sales staff. All personal information in these correspondence records are, of course, kept completely confidential. However, improving the quality of the items we sell is not simply a problem of finding solutions within our supply chain. Using compiled results, we aim to clarify the type and level of problems users experience with leather goods, leading to overall quality improvement of supply items of scale. However, we cannot perform this task alone. As a survey method, it is based on compiling all 7,000 records of leather goods over the past decade sorted by our original ‘product-code’ and ‘consultation-code’. By using compiled results, we are able to clarify what kinds of items and what kind of complaints is more often in major sales items. Additionally, by using text extraction from the content of customers’ requests and compiling them manually, totals can be determined for each use period and product color. For example, we can compare customer complaint data with test results for colour fastness. Referring to required performance items specified by ISO standards, the gap between customer requests and quality standards can be clarified. With the internationalization of purchasing networks of sales items, quality control based on setting various safety and quality standards is becoming increasingly important. In terms of the characteristics of leather, we think that there is probably a level that is impossible to realize, however, not only the problems of regulations and safety but the nature of the customer's viewpoint must also be discussed. Take-Away: We are going to present current data showing proof of what consumers actually want. Using this data, leather goods manufacturers can efficiently make products that consumers want and avoid making products that consumers don’t want. We suggest that quality standards , including ISO, should consider not only safety and regulations of environment, but consumer`s opinions as well.

Content: In this study, equipped charcoal of Ficus carica without impregnation, impregnated with potassium hydroxide (KOH), zinc chloride (ZnCl2) and phosphoric acid (H3PO4) was used for sorption comparison of trivalent chromium from tannery wastewater. The equipped charcoal is characterized before and after used by Fourier transforms infrared spectroscopy (FT-IR). The quantitative elemental analysis is performed of the charcoal using PGT Energy dispersive X-ray spectrometry (EDX). The trivalent chromium sorption efficacy of charcoal was examined investigating charcoal dose, contact time, and relative pH parameters. Batch sorption test revealed that Ficus carica charcoal without impregnation had the maximum sorption capacity of trivalent chromium as depicted Fig. 1a. At the same conditions, trivalent chromium sorption on the Ficus carica charcoal without impregnation, impregnated with potassium hydroxide, zinc chloride and phosphoric acid was 98.9%, 98.8%, 8.9 and 2.5%, respectively. It is noticeable that without impregnation charcoal has a higher sorption capacity. Conversely, impregnation with chemical required cost involvement, time-consuming, long process time, and safe. Fig.1b depicts a shift in the peak intensity which indicated the change of frequency in the functional groups of the charcoal due to chromium adsorption. It indicates various responsible functional groups for the removal of trivalent chromium through Ficus carica charcoal. The trivalent chromium removal efficiency with the Ficus carica charcoal without impregnation was achieved 98.9%. The study could be helpful to design the sorption of trivalent chromium from the tannery wastewater in-house prior to discharge. Take-Away: 1. Without impregnation, Ficus carica charcoal has a better trivalent chromium sorption capacity 2. Trivalent chromium sorption capacity was 98.9%

Content: The retanning process is considered as one of the most important processes in leather making, and it plays an important role in the modern leather industry. The fibre structure of hide or skin is not uniform and the retanning agent improves the properties of leather by filling the empty part of wet-blue leather. It could contribute to further stabilization of collagen fibres and give better handle properties to leather such as fullness and elasticity. In a conventional leather retanning process, retanning materials used include both inorganic salt like basic chromium salt, zirconium salt and aluminum salt and organic materials such as vegetable tanning agent, synthetic tanning agent, resin retanning and aldehyde tanning agent. Extract from the barks of Acacia seyal (Talh bark), widely distributed in Sudan, has been evaluated for its utilization in the retanning of the leather and presented in this paper. Barks of talh have been extracted for 1 hour with distilled water (1:10 w/v) at temperature above 80˚C. The talh extract prepared has been used for the retanning of wet blue leathers. The effectiveness of talh extract in retanning of wet blue leathers has been compared with mimosa retanning. The organoleptic properties of the leathers viz. softness, fullness, grain smoothness, grain tightness (break), general appearance, uniformity of dyeing of talh retanned leather have been evaluated in comparison with mimosa retanned leathers. Talh retanning resulted in leathers with good grain tightness. Dyeing characteristics of talh retanned leathers have been found to be better than mimosa retanned leathers. Also physical strength characteristic and shrinkage temperature and economic viability were noted. The effluent arising from this retanning system has been analyzed for its environmental impact. Take-Away: Organoleptic properties physical strength characteristic Shrinkage temperature

Content: Tannins are high molecular weight polyphenols, naturally synthesized by plants to defend themselves against biotic and abiotic stress factors. Their role as antioxidant, antibiotic and antibacterial agent has been known for many years among agriculture, food, pharma and cosmetics industry. If tannins would perform an antibacterial activity in a vegetable tanned leather, the leather itself could be certified as an antibacterial material. This effect could be very interesting for all the applications in which the leather, being in contact with sweat and bacteria, becomes a solution to reduce more or less severe hyperhidrosis and bromhidrosis. The goal of the study was the assessment of the antibacterial activity of vegetable tanned leathers with natural tannins to produce articles in direct contact with human skin and, therefore, their effect on sweat, bacterial growth and metabolite production. Firstly, the antibacterial activity has been evaluated and compared between leathers tanned with Chestnut, Quebracho and Tara extracts, chrome tanned leathers and synthetic materials. The trial was performed in vitro by inoculating gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacterial strains. A later step defined the most suitable blend of tannins to obtain, after tanning and/or retanning, an antibacterial natural leather. Furthermore, the vegetable tanned leathers, made with this tannins blend, have been the target of an in vivo trial during which 15 panelists have worn two differently made shoes. The lining and insole inside the right shoe have been made with vegetable tanned leathers with tannins, while the ones inside the left shoe contained only synthetic material. The shoes have been worn for 28 consecutive days, followed by a molecular and bioinformatic analysis of microbiota samples taken from the inner surface of the shoes by using a sterile swab. Lastly, a biochemical analysis of volatile short chain fatty acids has been carried out to investigate the byproducts of the bacteria responsible for the unpleasant odor of shoes. Take-Away: 1. Vegetable tanned leather is a wonderful antibacterial material thanks to the presence of natural tannins, such as chestnut, quebracho and tara. This property is appreciated in the production of insole leather, lining, leather goods and automotive interiors. 2. The problem of bromhidrosis (bad feet odor) can be avoided by using vegetable tanned leather. 3. In particular, vegetable leathers tanned with tannins used to make inside part of the shoes permit to avoid the formation of cheesy and acidic odours thanks to their antibacterial properties and their capacity to absorb sweat.

Content: Wastewater from tanneries besides having toxic compounds also contain nutrients such as carbon, phosphorus, and nitrogen, which facilitate the rapid multiplication of microalgae. Currently, many types of researches search microalgae capable of growing in industrial effluents, exploiting the advantages of removing the nutrients present in these waters and producing biomass with high value- added. The liquid effluents produced in tanneries for finished leather have essential nutrients for the growth of microalgae, but also some compounds that may restrict or hinder the growth of microalgae in this medium. Therefore, the present work has the objective to evaluate the growth of a microalgae consortium (collected in a wastewater treatment plant of a beamhouse tannery) for the removal of phosphorus and ammonia from wastewater streams of a tannery (processing wet-blue to finished leather) with different photoperiods. Microalgae consortium was cultivated at two different compositions of mixtures of raw wastewater (R) and wastewater after secondary biological treatment (B): 50% of R + 50% of B, (50R50B) and 75% of R + 25% of B, (75R25B), in photoperiod of 24 hours and 12 hours of light, temperature of 25 °C and constant aeration. The growth of microalgae in the effluent and the removal of phosphorus and ammonia were monitored throughout the cultivation. The microalgae consortium presented maximum biomass concentrations in the 75R25B effluent (1.40 g L-1) and phosphorus removal (97.64% for the 50R50B and 95.54% for the 75R25B) effluent and ammonia removal (100%) for both effluent with 24-hour photoperiod light. Take-Away: In this study, it was found that the microalgae consortium can survive in wastewater from tanneries (processing wet-blue to finished leather) and exhibit removals of phosphorus and ammonia from the medium. The 24-hour light photoperiod presented better microalgae growth and nutrient removal results.