Content: Fine hair is the biggest seasonal challenge for bovine leather production in the United States. The origin, timing and severity of the fine hair problem can be unpredictable and vary from year to year. Seasonal changes on the hair growth cycle are prompted by the lower temperature from fall to winter; the cow hair increases in amount, length and thickness. This problem is very old and has increased in intensity due to changes in the leather manufacturing process, cattle breeding conditions and breed diversity. The amount of fat and thickness of the hide also play important roles. The extent of the problem has not been documented and is not fully understood by the scientific community. The presence of fine hair (residual hair) on the wet blue and final leather are a cause of downgrading the leather. If the wet blue has fine hair, it cannot be removed in further processing in crust or finishing. Some leather types can tolerate more fine hair than others. In this paper we will conduct a scientific evaluation of the fine hair on American bovine hides, wet blue and finished leathers through cross sections and stains, optical and electron microscope observations. We will include measurements of hair thickness and hair depth inside the hide. The work will compare sulfide and oxidative unhairing of winter hides, characterize and show the details of the fine hair through cross sections, and offer indicative measures to minimize the problem. Information from the largest wet blue manufacturer in the US with four tanneries will provide insight on the fine hair seasonality, types of breeds and cattle displacement temperature ranges and will discuss adaptive changes needed in the “Winter” time to control the fine hair. Take-Away: 1) scientific review and evaluation of the problem of fine hair though cross sections and stains, optical and electron microscopy observations 2) evaluate the fine hair on sulfide and oxidative unhairing; providing indicative measures to minimize the problem 3) characterize the seasonality of the fine hair problem regarding the types of breeds, displacement temperature ranges and adaptative changes to control the fine hair

Content: In order to contribute to a more sustainable leather manufacturing process and leather value chain, in 2016 Smit & zoon started its own designing process of new products through the Bio-Based innovation platform. As a logical first step, answers to several key questions have been looked for: What is Bio-Based? What is renewable? Which term and method do we use to define the Bio-Based content in the Bio-Based platform? What is biodegradable? How do our current products perform? What is our vision for future products? In the process of answering these questions and guided by the Cradle-to-Cradle (C2C) CertifiedTM program, Material Reutilization Score (MRS) was used to obtain deeper insights into the formulation and environmental performance of our leather chemicals and treated as the basis for the design of new generation bio-based chemicals. Three main focus areas are setting the tone of current activities in the Bio-based platform: 1. increasing the renewable contents of the existing product groups; 2. smart valorization of industrial side streams from biological origin and 3. improving the biodegradability of leather chemicals. While focusing on these topics, it is well-understood that a proper balance needs to be found between cost, sustainability and performance. In the meantime, leather’s end of life scenario plays a role and needs to be looked at again. One of the first results of this focused approach is our patentpending polyphenolic syntan product, in which industrial lignins are used during the chemical conversion process to replace part of the phenol (40-50 w/w%) used in the production of otherwise 100% petro-based polyphenolic retanning chemicals. We have shown that our innovative technology is compatible with most of the industrial lignins (kraft, soda, organosolv, hydrolysis) from different origins (soft/hard wood, grass, straw). The obtained polyphenolic products have real tanning power and are suitable to be used as retanning agents for various types of leather rendering good organoleptic properties with additional added value of increased bio-based content, improved biodegradability thus a higher MRS. The improved biodegradability of these products can contribute to decrease the effluent treatment load. Moreover, these products can be tailor-made to meet low emission (low free phenol, low free formaldehyde) requirements as well. In addition to the lignin-based polymers, the quickly developing project portfolio within the biobased platform manifests that Smit & zoon is making steady steps towards a largely sustainable leather value chain by 2025. Take-Away: Bio-Based products contritbute to a sustainable leather manufacturing process and leather value chain. Both the raw material renewability and product biodegradability are important parameters to evaluate the environmental impact of leather chemicals. Smit & zoon has developed a patent-pending bio-based synthan product using industrial lignins to replace part of the petro-based phenols in the production process.

Content: Car industry is highly demanding for low emission parameters and despite remarkable results have been achieved since the last decade, the requests are day by day more sophisticated. The focus on emission is a severe task and requires the investigation on emissions on full-range and involves the expertise of multi and inter disciplinal competences. The leather industry is a clear key ring for car interior suppliers and it is also focusing on more sustainable processes and reducing the emission of pollutants to the environment, prompting the commitment of leather suppliers, tanneries, and chemical auxiliaries producers. From our perspective, in fact, one of the major problems that car interior producers are currently facing is the production of low-emitting leather, which requires special chemical auxiliaries to be achieved. In this context, our research has focused on the study of VOC volatile substances from car interiors, in particular on finishing systems, aiming at their reduction without losing the original performances of the finished leather article. Our investigation focused on full grain finished leathers, evaluating the contribution to the VOC emission from crust leather to the finished articles. A preliminary study showed that silicon compounds family brought an important contribution to the emission from a qualitative and quantitative perspective: these substances play a crucial role in terms of the final article performances (such as resistance), and quality. So, our investigation focused on innovative silicon-free auxiliary combination to give low VOC emission contribution from the leather compared with the same performances of the original silicon containing finishing. In order to evaluate the impact of the emissions, a series of analyses of the volatiles were performed: static headspace VDA 277 (and/or PV3341) analysis and active air sampling analysis GS 97014-3 type were performed, indicating that silicon contribution was very high in the emission. In addition, the quality of the leather was also assessed and characterised through standard automotive tests such as stick-slip, abrasion trials with Taber tester and Martindale machine, ball plate method, fogging test; rub fastness provided with Veslic tester (wet, dry, alcohol, gasoline), dry-rubbing trial with Gakushin tester. The set of result showed that standard leather containg silicon compounds on the finishing produced high VOC emission and high performance articles, thus contributing to VOC emission. Conversely, the novel finishing auxiliaries had low VOC emission, no silicons, yet high performance leather and therefore should be chosen from a more environmental point of view. Take-Away: Low VOC emission from novel leather finishing albeit high resistance leather.

Content: Providing peculiar enhanced features to leather items is a factor of primary importance for the marketing of high-end articles; although the tanning production is oriented to satisfy a wide market range, it is mainly in the 'high end' and 'premium luxury' categories that the quality properties of the material are more expressed, indeed, and where the main current challenges have been focalized, in terms of technological innovation, sustainability and product quality. The light-coloured leathers belongs to the category of materials designed especially for the luxury market. For this type of articles, the uniformity of the colour and the agreeableness of the overall surface appearance are crucial requirements for the most of international fashion and luxury brands. One of the most common and undesirable defects of this type of article is the alteration of the color, with particular reference to the effects of yellowing of the surface of the material. There are several causes able to contribute to this type of defects, due to the complexity of the matrix and to the variability of traditional or innovative production processes used: from the fragility, photosensitivity and thermo-sensitivity of the finishing polymers, to the chemical instability of some finishing pigments, further than the presence of photosensitive additives, the migration of skin components or assembly components of the articles (fats, fillers, plasticizers, glues, etc.), up to the indirect contribution of environmental and thermo-climatic factors able to affect negatively the performance of the material. SSIP, which has always been involved in research and consulting activities for the leather industry with regards to defect monitoring, through this work, would offer an overview of all the main tools for advanced diagnostics (with particular reference to Scanning Electronic Microscopy and to chromatographic and spectroscopic methods) aimed to the identification of the causes of yellowing, beside to explore innovative solutions for the development of strategies for the resolution and / or minimization of the problem of yellowing. The technical solutions will include innovative tanning processes, innovative finishing methods, and leather surface treatments carried out in order to provide a sensible attenuation of surface absorption of IR (infrared) and UV (ultraviolet)-visible radiation. Take-Away: Advanced Diagnostics and innovative solutions for leather yellowing

Content: It is acknowledged that conventional chrome tanning in leather processing discharges significant amounts of chromium, dissolved solids and chlorides. The recycling technology is one of the effective solutions to reduce the environmental impact of chrome tanning waste water at source. In this work, a novel closed recycling technology of chrome tanning wastewater was applied in the tanning process of the goat skins at a pilot scale level. The properties of chrome tanning liquors obtained by the recycling technology and the resultant crust were analyzed. The results show that this close recycling process works well. The contents of Cr2O3, total organic carbon, ammonia nitrogen and chloride ion in the waste water tend to accumulate with the increase of recycling times, and finally reach a balance after 5 times of recycling. The obtained leather sample is full, soft and having a shrinkage temperature comparable to that of conventional chrome tanned leather. SEM images indicate that the resulting leather samples by this recycling technology show fine and clean grain and well-dispersed fibrils. TG and DSC results show that the thermal stability of wet blue leathers tanned by the circular process are similar to those tanned by conventional chrome tanning process. Compared with conventional chrome tanning technology, water, salt and chrome tanning agent are saved in this process, and the zero emission of chrome tanning wastewater is realized. The cleaner production technology exhibits promising application prospect for its economic and environmental benefits. Take-Away: 1. A novel closed recycling technology of chrome tanning wastewater was applied in the tanning process of the goat skins at a pilot scale level. 2. The chrome tanning liquors obtained by the recycling technology and the resultant crust were analyzed. 3. Water, Sodium chloride and chrome tanning agent are saved by the closed recycling technology, and the zero emission of chrome tanning wastewater is realized.

Content: As it is known in the tanning sector, in recent times, the so-called wet-white and/or metal-free concepts have had a certain increase. For example, in the automotive sector, the wet-white tanning system, carried out with glutaraldehyde and tannins, has been widely diffused. In fact, car manufacturers offer, for interior furnishings, leather not only for high-end cars but increasingly also in the lower segments. The components on which the leather upholstery is applied are mainly steering wheel, seats, dashboard and panels. Therefore, the use of leather also in this context must be able to meet both the aesthetic/performance criteria and the environmental ones; environmental criteria should also consider the air quality of the interior of a motor vehicle. In practice, the interior furniture consisting of finished leather must be able to release a few volatile substances and, at the same time, provide a typical smell of leather. Considering, therefore, the diffusion of alternative chrome tanning systems for the different uses, in this work, wet-white (glutaraldehyde and tannins) will be investigated, both from the point of view of the performance characteristics and from the ecotoxicological ones. and leathers deriving from the latest generation of metal-free tanning. For the characterization of Volatile Organic Compounds (VOC) the GC-MS will be used coupled with the 'Purge and Trap' technique with the aim of obtaining information on the new substances used in the wetwhite / metal free production process and then avoiding undesired effects during use (eg bad smell, SVHC substances, etc.) Take-Away: metal-free automotive VOC

Content: Surfactants are used as auxiliaries in every wet processing process of leather production and discharged into wastewater, which would cause potential ecological risks. In this paper, fresh luminescent bacillus liquids were employed to evaluate the ecological toxicity of six surfactants, including anionic, cationic and non-ionic surfactants, and mixture of two typical ionic and nonionic surfactants after a 15-min exposure period. Non-ionic surfactants AEO and Tween80 showed slight light inhibition ie.10-35% to luminescent bacteria. The toxicity of anionic surfactants with polar sulfonic group was: penetrant T(EC50=406.81mg/L) ＞SDBS(EC50=573.37mg/L). The toxicity of cationic surfactants was: DTAB（EC50=10.68mg/L）＞SKC （EC50=73.96mg/L）. The addition of nonionic surfactants reduced the toxicity of ionic surfactants. 1-1 mixture of SKC and AEO: EC50=80.17mg/L, 1-1 mixture of SDBS and AEO: EC50=624.34mg/L. These results provided ecological parameters for the selection of surfactants in the process of ecological leather production. Take-Away: 1. The toxicity measurement by luminescent bacteria, which is simple and convenient, was used to evaluate the toxicity of surfactants, and the reproducibility was improved in our study. 2. The toxicities of six different surfactants was evaluated by EC50 which provided ecological parameters for the selection of surfactants in the process of ecological leather production.

Content: Chamois leathers are basically oil tanned leathers, usually requires 10 to 15 days to process from raw skins. In chamois making, air oxidation plays a major role, free radicals initiate the oxidation process in oil, which oxidizes the double bond of the fatty acid and then the oxidized oil interacts with collagen to stabilize the skin by coating the fibers (Fig 1). In the present study an attempt has been made to reduce the time for chamois leather processing. A common oxidizing agent (Benzoyl peroxide (BPO) was utilized to enhance the oxidation of oil and reduce the time duration. It has been observed that the oxidation of oil in the presence of benzoyl peroxide has significantly reduced the duration of process from 15 to 4 days. Strength properties such as tensile, percentage elongation and organoleptic properties were found to be on par with control leather. The water absorption values of the experimental leathers improved by 1-26 %, compared with control leather. Microscopic analysis (SEM) was employed to study the fiber alignment of the chamois leathers. Take-Away: 1. Time reduction in chamois leather processing 2. Inexpensive and common oxidising agents were employed 3.Improved water absorption of chamois leather

Content: Unhairing process is usually considered as the most polluted process in leather production. The conventional method of unhairing which using lime and sodium sulfide produces a large amount of sludge and waste water. In order to reduce pollution, we developed a novel unhairing enzyme and named as WB600-KerT, which possesses low collagen-degrading ability and high keratin-degrading ability in previous study. The objective of this study is to study the properties and effect of WB600-Kert to replace traditional chemicals in unhairing process. It found that the protease of WB600-Kert exhibited optimum keratin activity at 40°C. Compared with commercial unhairing enzyme and conventionally sodium sulfide methods, WB600 exhibited better unhairing effect and higher efficiency. The results indicated that goat skin unhaired with WB600 achieve enough softness, shrinkage temperature and tear strength as well as conventionally sodium sulfide methods Furthermore, if adding a small amount of sodium sulfide, the unhairing process could be accelerated while the unhairing effect was further improved. Generally speaking, this enzyme showed good application potential in unhairing process and was effective for reducing pollution which may promote the development of leather industry. Take-Away: 1. The protease of WB600-KerT was firstly applied to hair removal. 2. The addition of little sodium sulfide in WB600-KerT could enhance unhairing efficiency.

Content: This paper briefly introduced the process of leather manufacture and the potential pollution sources of soil in tannery sites. Pollutants are mainly derived from the use of a large number of various chemicals and organic matter decomposed by raw skin. The characteristics of typical pollutants in tannery sites soil were summarized, including tannery site soil pH, organic and inorganic compounds, and heavy metals, etc., especially the status of chromium contamination were reviewed. The pH of soil in the tanning workshop (6.65-7.8) is generally lower than tannery sludge dumping site (7.94-8.40). The main organic pollutants contained in the tannery site soil include nitrogen compound, grease, petroleum hydrocarbon. In tannery sludge dumping site soil, the content of nitrogen compound (10cm depth) is 28400 mg/kg, which is similar to tannery sludge. The content of petroleum hydrocarbon is 5-700 mg/kg, which partially exceed the limits of China agricultural land quality standard(<500 mg/kg). In tanning workshop soil, the content of grease is 220-62000 mg/kg. The main inorganic pollutants contained in the tannery site soil include sulfide, high concentration of salt, lime. The high salt content of tannery sludge (99000 mg/kg) leads to high salt content in soil (5500-17500 mg/kg). Total hardness (>450mg/L), total dissolved solids (>1000mg/L), sulfate ions (>250mg/L), nitrite nitrogen (>0.02mg/L) partially exceed the limits of China groundwater quality standard, which are found in groundwater below the tannery site. Heavy metal pollutants in the tannery sites soil have many characteristics and large differences in content, due to the different tanning processes. Among them, chromium (Cr) is the most used heavy metal and the highest content of pollutants. Cr content in tanning process wastewater, dyeing process wastewater and chromiumcontaining sludge are about 2000-3000 mg/L, 30-40 mg/L and 8500-25800 mg/kg, respectively. Total Cr content in the partial tannery sites soil are higher than 800 mg/kg, which exceed the limits of China agricultural land quality standard(<150mg/kg). Surprisingly, Cr(VI) appears in tannery sites soil and the contents are partly higher than 40 mg/kg, which exceed the limits of China development land quality standard(<3.0mg/kg). Furthermore, the more effort needs to be directed toward the chemistry of chromium-organic complex pollutants, and an understanding of the speciation of Cr in highly organics contaminated tannery site soil is essential for the development of suitable remediation strategies for contaminated soil. Take-Away: 1. The pH of soil in the tanning workshop (6.65-7.8) is generally lower than tannery sludge dumping site(7.94-8.40). 2. Total Cr content in the partial tannery sites soil are higher than 800 mg/kg, which exceed the limits of China agricultural land quality standard(<150mg/kg). 3. Cr(VI) appears in tannery sites soil and the contents are partly higher than 40 mg/kg, which exceed the limits of China development land quality standard(<3.0mg/kg).