Content: Chrome tanning is the commonest tanning agent in leather manufacture, and the discard of chrome tanned leather goods inevitably leads to chrome discharge that might have potential environmental risks. In this study, the kinetic behaviors of the release of chrome and organics were investigated by ICP-OES and TOC analyzers respectively. Deionized water was used as medium, and leaching tests were proceed at solid liquid ratio 1:20 as well as rotational speed 60 r/min to simulate the release of chrome tanned leather under natural conditions. The effect of temperature on the behavior kinetics was further explored. The results showed that the release of chrome and organics could be well fitted by the second-order kinetic equation, and the rate constant for the release process indicated the release of organics was faster than chrome. Then Tenax model was used to illustrate the release kinetics experiments of chrome to obtain the three release compartments (fast, slow and very slow). The results could provide the theoretical parameters for the assessment of risks of chrome-tanned leather. Take-Away: The second-order kinetic equation could describe the release of chrome and organics from chrome tanned leather under natural environment. The activation energy of the release of chrome and organics from leather could be obtained. The fast, slow and very slow compartments of chrome release could be obtained.

Content: In today’s business environment, organisations are increasingly reporting their sustainability credentials through different channels. However, in a traditional industry with a complex supply chain as leather, many companies do not publicly disclose details of their sustainability activities, while a considerable number of companies report on the environmental sustainability aspect alone. Hence, this study identifies good practices of sustainability reporting, discussing the sustainability information extracted from the reports of a selected number of companies in the leather industry. A thematic content analysis was used to extract sustainability information from either the website, annual report, sustainability report or corporate social responsibility report of six leather companies. A review of existing literature assisted in categorising different practices under the three sustainability dimensions while a highlight of patterns among practices followed. The results show that the companies are observing a good practice of either dedicating a section of their website to revealing their sustainability activities or utilising their sustainability reports. Additionally, these companies follow a good practice of reporting their activities based on the economic, social and environmental sustainability dimensions, rather than focusing on just one of the aspects. Amongst the six companies, energy efficiency and reduction in greenhouse gases emission were the most occurring environmental sustainability practices. On the other hand, health and safety occurred as the dominant social sustainability practice of the leather industry, while economic sustainability practices have not been well defined, providing an opportunity for future research. Conclusively, the study provides a useful resource for managers and companies in the leather industry to learn from brands that have been embarking on sustainability efforts and assist them in getting a grasp of the concept, in readiness for strategy formulation, implementation and reporting. This study provides knowledge of the sustainability criteria to be met by small, medium sized and large leather supply chain actors on their sustainability journey. Take-Away: 1. The companies are observing a good practice of either dedicating a section of their website to revealing their sustainability activities or utilising their sustainability reports. 2. The companies also follow a good practice of reporting their activities based on the economic, social and environmental sustainability dimensions, rather than focusing on just one of the aspects. 3. Energy efficiency and reduction in greenhouse gases emission were the most popular environmental sustainability practices, health and safety was the dominant social sustainability practice while economic sustainability practices have not been well defined.

Content: Today, automotive leather has to meet a multitude of requirements for different automotive brands. In addition to the important traditional aesthetic properties, such as the feel and appearance of the leather, a growing number of measurable specification parameters have been added over time. One of these parameters are the Volatile Organic Compounds (VOC) which the final leather article emits. The large number of emission specifications, each with its own limits, represents a major challenge in the development of automotive leather today. Each of these methods has a slightly different substance focus and highlights certain groups of volatile substances in the test result. This often makes a targeted development for a certain leather article with associated test method necessary. The recurring question of how to further reduce the emissions of automotive leather is answered by presenting the latest developments from the Leverkusen laboratories as one focus of this work. The increasingly profound measurement of the emissions over the last decades has led to VOCs becoming reduced from grams to micrograms per kilogram of leather. Most probably because of this dramatic reduction in VOC levels, the focus of the regulations has switched today more from quantity of emissions to the properties of single substances emitted. Often the exact source of these substances were initially unknown and consequently a specific solution to meet the limits were not available. The search for the sources is becoming increasingly complex and difficult as many of these substances are not applied directly but are often degradation products of other compounds. Often the measured low concentrations are in the range of the natural decomposition processes. Nevertheless, it is possible to identify some of the sources by evaluating the results of different analytical methods. Thus it is now possible to develop suitable countermeasures. The presentation of the source of special single volatile organic substances as well as their reduction forms a further focus of this work. Take-Away: Reduction of Emissions Finding sources of substances emitted from leather Presenting countermeasures to reduce those substances

Content: The composition, working principle and the image acquisition procedure of nano-CT were introduced. A dried piece of blue stock of chrome-tanned cattle hide was chosen for this work and a sequence of 2356 images was obtained. 3D visible digital models (5mm*3.5mm*3.5mm) of leather fiber bundle braided network (Figure 1) and the interspace between fiber bundles (Figure 2) were reconstructed. The inner structure and composition of leather were shown accurately and intuitively in the form of 2D sectional images and 3D image. Based on the 3D model, the diameter, volume, surface area and other parameters of the fiber bundles, the pore structure and inclusions were measured and calculated. Take-Away: 1. 3D visible digital model of leather fiber bundle braided network was reconstructed. 2. The inner structure and composition of leather were shown accurately and intuitively in the form of 2D sectional images and 3D image.

Content: The understanding of how chemical, physical and environmental parameters work during anaerobic digestion production and waste treatment is an important step in improving the efficiency and process stability. This study provides the evolution of the biogas production and the efficiency of the treatment of the anaerobic digestion of solid wastes of tanneries at-line monitored in batch laboratory-scale bioreactors. Leather shavings and sludge from wastewater treatment plants substrates were considered in the study. The findings suggest that AD of the tannery solid waste can be separated into three phases: a long lag phase, a log phase with a low metabolic rate and the final phase where all the shavings were metabolized. Take-Away: The AD of the tannery solid waste can be separated into three phases: a long lag phase, a log phase with a low metabolic rate and the final phase where all the shavings were metabolized

Content: The braiding structure of leather fibers has not been understood clearly and it is very useful and interesting to study it. Microscopic X-ray tomography (MCT) technology can produce cross-sectional images of the leather without destroying its structure. The three-dimensional structure of leather fibers can be reconstructed by using MCT slice images, so as to show the braiding structure and regularity of leather fibers. The denoising and segmentation of MCT slice images of leather fibers is the basic procedure for three-dimensional reconstruction. In order to study the braiding structure of leather fibers in the round, the image of resinembedded leather fibers MCT slices and in situ leather fibers MCT slices were analyzed and processed. It is showed that the resin-embedded leather fiber MCT slices were quite different from that of in situ leather fiber MCT slices. In-situ leather fiber MCT slice image could be denoised relatively easily. But denoising of resin-embedded leather fiber MCT slice image is a challenge because of its strong noise. In addition, some fiber bundles adhere to each other in the slice image, which are difficult to be segmented. There are many methods of image denoising and segmentation, but there is no general method to process all types of images. In this paper, a series of computer-aided denoising and segmentation algorithms are designed for in-situ MCT slice images of leather fibers and resin-embedded MCT slice images. The fiber bundles in wide field MCT images are distributed densely, adherent to each other. Many fiber bundles are separated in one image and tightly bound in another. This brings great difficulties to image segmentation. To solve this problem, the following segmentation methods are used: Grayscale-threshold segmentation method, The region-growing segmentation method, Three-dimensional image segmentation method. The denoising and segmentation algorithm proposed in this paper has remarkable effect in processing a series of original MCT slice images and resin-embedded leather fibers MCT slice images. A series of threedimensional images based on this work demonstrate the fine spatial braiding structure of leather fiber, which would help us to understand the braiding structure of leather fibers better. Take-Away: presentation ppt, Figures

Content: The intrinsic structure significantly influences the mechanical properties of leather. In consequence, knowledge of leather’s hierarchical structure is essential in order to find the most suited leather for specific application. Leather structure based parameters are of major importance for both manufacturing and leather processing industries. In this respect, intensive structure investigations have been subjected in continuous research work. Quantitative image analysis combined with stochastic micro-structure modelling and numerical simulation of macroscopic properties is a promising approach to gain a deeper understanding of complex relations between material’s micro-structure geometry and macroscopic properties. Key ingredient is a reliable geometric description provided by the quantitative analysis of 3D images of the material micro-structures. For leather, both imaging and image analysis are particularly challenging, due to the multi-scale nature of the leather’s micro-structure. Scales in leather are not well separated. Previously, high resolution computed tomography allowed 3D imaging of purely vegetable tanned leather samples at micro- and submicro- scale. Segmentation of leather structure as well as of typical structural elements in resulting image data is however hampered by a strong heterogeneity caused by lower scale structural information. The first method for automatic segmentation of typical structural elements at varying scales combined morphological smoothing with defining and iteratively coarsening regions using the waterfall algorithm on local orientations. It yields a hierarchical segmentation of the leather into coarse and fine structural elements that can be used to analyze and compare the structure of leather samples. Size and shape of the structural elements as well as their sub-structure yield information, e. g. on undulation, branching, thickness, cross-sectional shape, and preferred directions. In order to compare the micro-structure of leather samples from various body parts or even species, the segmentation has to be applicable without extensive pre-processing and parameter tuning. Robustness can be gained by applying smoothing methods that are adapted to the goal of defining image regions by similar local orientation. The challenge is that the space of fiber orientations in 3D is not equipped with an order. Motivated by a recent approach for nevertheless defining erosion and dilation on the sphere, we suggest new definitions for these morphological base transformations on the space of directions in 3D. We present segmentation results for 3D images of leather samples derived by these new morphological smoothing methods. Take-Away: The intrinsic structure significantly influences the mechanical properties of leather. Leather’s hierarchical structure can be analyzed by quantitative 3D image analysis combined with stochastic micro-structure modelling. Segmentation results for 3D images of leather samples derived by new morphological smoothing methods.

Content: In this study, different proportions 2.5%, 5%, 10% of aluminum sulfate were used as tanning agents during parchment production. The research was carried out on goat skin and also there were no usage of any tanning agents as control groups. Finished leathers have been exposed to ageing conditions. Before and after ageing color measurements on all finished leathers have been conducted with Konica Minolta CM-3600d brand spectrophotometer. The impacts of the aluminum sulfate utilized in the research on light fastness were also inspected by using an ATLAS-XENOTEST ALPHA+ test instrument. Visible whitening on the color of parchment was observeded when tanning process with aluminum sulphate was performed. Take-Away: -Aluminum sulfate has tanning effects -Aluminium gave white color to the parchment -Aluminum sulfate changed collagen structure.

Content: Quality of leather is deeply dependant on the origin of the livestock including breeding, transportation and slaughter. Ten years ago, the French leather industry have commissioned CTC, the French Leather, leather goods and footwear research centre to improve the quality of hides and skins. In order to improve raw material, a unitary link is required between the quality of leather and its origin that is to say the raw material. This was the beginning of a huge project: traceability of hides and skins through the supply chain, from breeding to wet-blue (and even leather). Data is captured from the animal’s ear tag at the point of slaughter which is then transfer on to a paper bar code. Hides and skins traders will then transfer definitively the code from the paper tag to the hides or skins thanks to an automatic high-pressure CO2 marking device on the hair side of the fresh or salted hide in the neck region. That unitary traceability is resistant to water, acid, alcalis, grease, solvents but also mechanical impacts such as splitting, shaving and even buffing. It is visible throughout all the process and fast enough. Once the permanent number code has been added, it can be visually or automatically read throughout the subsequent tanning process steps. The automatic code reader takes the algorithm of the number and the data is collected by mean of artificial intelligence. This technology has been implemented by several abattoirs, trader and tanners. Traceability is the essential tool for quality management throughout the supply chain. It helps the identification of the origin of defects for improvement and provides the origin of grade 1 hides and skins. This realistic industrial solution is a major issue for the leather industry whether it is for the improvement of quality or mastery of the supply chain and sustainability. Take-Away: In order to improve the quality of raw material, a unitary link is required between the quality of leather and its origin that is to say the raw material. This is the objective of that project: traceability of hides and skins through the supply chain, from breeding to wet-blue (and even leather) thanks to CO2 laser marquing.

Content: Nowadays, tannery pollution is of great concern worldwide. The unhairing and fiber bundle-opening processes contribute the majority of the pollution by the use of sodium sulfide and calcium hydroxide, which were proposed to be replaced by neutral protease combined with (potassium chloride) KCl, (lithium bromide)LiBr/1-allyl-3-methylimidazolium chloride([AMIm]Cl) in the present work. Proper amount of KCl can speed up the unhairing with the grain not destroyed by the neutral protease. Four methods for unhairing and fiber bundle-opening were used as follows: 1. Two steps in different floats as KCl/neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 2. Two steps in different floats as neutral protease unhairing, followed by LiBr/[AMIm]Cl for fiber bundle-opening; 3. One step in the same float as neutral protease for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. 4. One step in the same float as neutral protease/KCl for unhairing firstly and then LiBr/[AMIm]Cl for fiber bundle-opening. It was found that using neutral protease/KCl solution for unhairing and LiBr/[AMIm]Cl solution for fiber bundle-opening is the best in fiber bundle-opening at the liming process. Besides, all the methods used here are better than the traditional liming processes (C) from viewpoints of unhairing and fiber bundleopening. Take-Away: 1. The addition of potassium chloride can improve the stability of neutral protease solution. 2. The catalytic efficiency of the enzyme was improved because of adding potassium chloride can enhance the contact rate of neutral protease with substrate. 3. Ionic liquids have less hydrolysis of collagen and larger dissolution of polysaccharides.