Content: Polyacrylate as film-forming materials has been widely used in leather finishing, but its compactness significantly obstructs the hygienic property of upper leather. Therefore, considerable efforts have been made to endow polyacrylate with required properties. In this study, we demonstrated a facile and rapid sonochemical process to synthesis the flower-like ZnO nanostructures. The related morphology and structure of product were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Meanwhile, flower-like ZnO were introduced into the polyacrylate matrix by physical blending method, whose morphology, latex stability, water vapor permeability and water resistance were measured. The results showed that flower-like ZnO assembled by ellipsoid-like nanorods with the length of about 600 nm was successfully fabricated. The sizes of flower-like ZnO were 1.2 μm. According to SEM images, flower-like ZnO evenly dispersed were observed in composite matrix. Compared with pure polyacrylate, polyacrylate/flower-like ZnO composites exhibited the superior stability. Meanwhile, its water vapor permeability and water resistancewere increased by 52.91% and 53.13%, severally. The reason for this is that ZnO with rough structure can increase voids in polyacrylate film and thus improving hygienic property of polyacrylate film. Additionally, the hydrophilic groups on surface of ZnO can product the crosslinking with polyacrylate chains, which contributed to the enhancement of water resistance. Thus, a promising coating with hygienic property and water resistance for leather finishing agent was approved. Take-Away: 1. Polyacrylate/flower-like ZnO composites exhibited excellent hygienic property. 2. This composite coating achieves simultaneous enhancement in water vapor permeability and water resistance. 3. The morphology of ZnO can effect the properties of polyacrylate.

Content: The application of split leather is an important issue in leather industry as most of them was not properly treated and wasted. In this study the application of choline chloride (ChCl), urea (U) and corresponding deep eutectic solvents (DES) on the modification of thermal stability and mechanical strength of mink split leather was investigated. TGA and DSC results indicated DES treatment enhanced thermal stability of split leather, and ChCl treatment reduced the stability. While, U treatment provided a kinetic inhibition during the thermal-decomposition. In terms of the mechanical strength, both ChCl and U treatment reduced burst intensity and extended height. While, after DES treatment the burst intensity and extended height increased significantly. In terms of the dosage, 7% DES provided best performance. Results mentioned above illustrated that DES formed by simply mixing ChCl and U provided strong interaction with fiber, enhanced the crosslinks. A hypothesis of [Ch(Urea)]+[Cl(Urea)]- type structure was proposed, as it enabled DES forming strong hydrogen bonds with functional groups on leather fiber, enhancing the crosslinks and therefore improving the thermal stability and mechanical strength. The DES treatment on leather fibers improved their overall performance and thereby broaden their applications. Take-Away: 1. DES obtained by mixing ChCl and urea presented very different effect in leather treatment, as the thermal stability and physical strength of leather improved significantly after the DES treatment. 2. A hypothesis of [Ch(Urea)]+[Cl(Urea)]- type structure was proposed, illustrating a formation of strong hydrogen bonds between DES and functional groups on leather fiber. This enhances the crosslinks and therefore improves the thermal and mechanical strength of leather.

Leather wastewater is one of the most polluting industrial emissions. An in-situ, green, and innovative strategy that limits dye emissions is required to replace subsequent waste management. A novel cationic protein with a high quaternary ammonium degree was designed and synthesized. The results show that at concentrations ranging from 3 to 15 wt%, this cationic protein rapidly and completely adsorbs Direct Purple N and Acid Black 24 within 5 min. A remarkable efficiency in removing Acid Red 73, Acid Golden G, Acid Lake Blue A, Acid Green, and Acid Orange II, with >96% removal rates, was achieved. The cationic protein was most accurately represented by the pseudo-second-order kinetic model. Acid Orange II (2000 mg L-1) and 15 wt% cationic protein were used in an actual tanning process. The residual concentration of Acid Orange II in the wastewater was 23.1 mg L-1. These results reflect that the emission reduction targets have been effectively achieved.

Content: The thermal degradation kinetics of hides before and after being tanned with formaldehyde were investigated using thermalgravimetric analysis (TGA) at four different heating rates of 5, 10, 20, 30 K/min. Such model-free methods as Flynn-Wall-Ozawa and Friedman as well as model-fitting method of Criado were employed to determine the thermal degradation active energy and degradation mechanism. Based on the Flynn-Wall-Ozawa and Friedman methods, the average active energy (Ea) of formaldehyde-tanned leather was 223.1 kJ/mol and 230.7 kJ/mol respectively. Results from general master curves showed diffusion processes in the thermal degradation of formaldehyde-tanned leather. Neither the thermal degradation activation energy nor the degradation mechanism is affected by the formaldehyde tanning. Nevertheless, the results by thermalgravimetric analyzer coupled with Fourier transform infrared spectrometry (TG-FTIR) indicated difference in the relative amounts of evolved products. According to the 3D-FTIR analysis, the dominant components of evolved gas for both untanned and tanned hides are CO2, CH4, H2O, NH3 along with small amount of HNCO. However, after formaldehyde tanning, both the evolved NH3 by the decomposition of free –NH2 groups and peptide –NH– groups from different amino acids in collagen and CH4 by the cleavage of -CH3 and -CH2- increase. Take-Away: 1. The theraml degradtion mechanism of hides before and after formaldehyde-tanning is eatablished in our paper. 2. The main degradation pathway of hides before and after formaldehyde-tanning is discussed with the help of TG-FTIR analysis.

Content: This article wants to combine two perspectives: First, Leather production, focused on the splitting process, with its diverse quality requirements and second, the new evolutions in the field of bandknife properties. In a short introduction the splitting process as such will be described, its different use in several stages and leather types, also in the field of leather conversion (in shoe, leathergoods and automotive parts production). Influencing factors of the possible goals like quality and cost efficiency will be discussed. In the second part some main requirements and problem fields of leather splitting are analyzed in more detail. Requirements such as thickness tolerance, tensile strength, flexibility, fibre-free smooth cutting surface. Difficulties in practice like chrome nests, hard water, poor raw material, feeding speed, influence of abrasivity of leather. In a third part the physics of the cutting process as such will be described. Explanation of basic terms as “cutting ability”, “edge retention”, “pull vs. press cut”. Resulting from this we get important parameters that refer to the bandknife blade: e.g. steel characteristics (hardness, flexibility, grindeability, microstructure at cutting point, geometry of knife bevels, weldability etc.). The possibilities in modern bandknife production will be shown as for example: CNC-sensor-based tolerance measurements, presharpening, surface roughness variations. This is completed with a short view on the other components of the process like splitting machine (points like sharpness measuring), grinding stones (roughness-exactness controversy diagram). The fourth and last part puts the two perspectives together: Optimized bandknife characteristics for specific leather material. Alternative steel types that due to new properties allow to meet also new requirements. Take-Away: Optimization of the splitting process Better understanding of the bandknife properties

Content: Identification and classification of leather species becomes valuable and necessary due to concerns regarding consumer protection, product counterfeiting, and dispute settlement in the leather industry. Identification and classification of leather into species is carried out by histological examination or molecular analysis based on DNA. Manual method requires expertise, training and experience, and due to involvement of human judgment disputes are inevitable thus a need to automate the leather species identification. In the present investigation, an attempt has been made to automate leather species identification using machine learning techniques. A novel non-destructive leather species identification algorithm is proposed for the identification of cow, buffalo, goat and sheep leathers. Hair pore pattern was segmented efficiently using k-means clustering algorithm Significant features representing the unique characteristics of each species such as no.of hair pores, pore density, percent porosity, shape of the pores etc., were extracted. The generated features were used for training the Random forest classifier. Experimental results on the leather species image library database achieved an accuracy of 87 % using random forest as classifier, confirming the potentials of using the proposed system for automatic leather species classification. Take-Away: Novel technique to identify leather species Non destructive method Machine learning algorithms to automate leather species identification

Content: Since hundreds of years, tanners share the opinion that hides from different cattle breeds lead to varying leather qualities. Especially European hides from the alpine region (e. g. Simmentaler or brown origin) are preferred by tanners. These leathers feature a higher thickness, a maximum utilisation induced by a minor thickness difference over the whole area and a lower tensile strength in contrast to leathers from other breeds. However, are these alpine hides better because of their breed affiliation or because they are kept in special regional conditions? It is known that, besides the breed, also other factors can influence the rawhide and leather quality like age, gender, nutrition and climate conditions. In addition, present dairy and beef cattle are high-performance cattle by breeding, which leads to more crossbreeds than 100 years ago. Our intention was to find out, whether leather quality nowadays is still a function of breed or not. For that purpose, 40 rawhides from four different cattle breeds (Angus, Charolais, Simmentaler, Limousin) were collected from the Saxon region. From each breed, five male and five female rawhides were collected. The age of each individual was restricted to two years. All 40 rawhides were tanned with the same technology for furniture leather. Leather quality was characterized by determining chemical and physical parameters. Chemical parameters included collagen content, fat content and ignition lost (DIN 181218). The physical parameters were tensile strength (DIN EN ISO 3376), elongation at break (DIN EN ISO 3376) and stitch tear resistance (DIN EN ISO 23910). The analyses revealed that the chemical parameters were identical for all examined breeds. For this reason, the chemical composition of a cattle skin is irrespective of breed origin. The tensile strength of the leathers showed only a small significant difference between Angus and Limousin (p= 0.05). Leathers from Limousin hides showed significantly different elongations at break compared to Angus, Charolais and Simmentaler. The stitch tear resistance varied in nearly all breeds. Significant differences were detected between all breeds except between Angus and Charolais as well as Angus and Simmentaler. Plotting the measured physical values against gender or age of the individuals showed no correlation. In summary, only minor differences between the cattle breeds were found. But this tendency must be confirmed by a larger quantity of test individuals. For this purpose, an analysis is planed with 100 individuals from different breeds and crossbreeds. Take-Away: Many tanners share the opinion that hides from different attle breeds lead to varying leather qualities. We found only minor differences of the physical parameters between the cattle breeds with a random sample of 10 individuals per breed. To confirm this tendency, an analysis is planed with 100 individuals from different breeds and crossbreeds.

Leather is a material that throughout history has been very important for humankind. Up until recently is has often however, together with other organic materials, not been given the attention it might deserve. This essay investigates how leather from the Late Iron Age in Scandinavia can be studied, if specialisation within leather related crafts can be identified and what this can tell us about how crafting skills were spread in a society. First a broader analysis is made of related crafts in the Late Iron Age, which is then put into relation to three chosen Vendel Age graves from the Valsgärde burial ground. Both leather production through hunting and tanning, and item production techniques like for example sewing and scabbard making are reviewed. Problems with preservation are discussed and possible alternative ways to study the subject are explored. The essay concludes that leather crafting included many techniques spread in society, practiced by common people. Still, several explicit specialisations also existed, which created high-quality leather products. Finally, suggestions for future research are made. / Läder har som material varit mycket viktigt genom hela den mänskliga historien. Fram tills nyligen har det, tillsammans med andra organiska material, dock ofta inte fått den uppmärksamhet det kanske förtjänar. Den här uppsatsen undersöker hur läder från den sena järnålderns Skandinavien kan studeras, om specialisering inom läderhantverk kan identifieras och vad detta kan berätta för oss om hur hantverkskompetens var spritt i ett samhälle. Först görs en bredare analys av relaterade hantverk under den sena järnåldern, vilket sedan sätts i relation till tre vendeltida gravar från gravfältet i Valsgärde. Både produktion av läder genom jakt och garvning, och tekniker för produktion av föremål såsom sömnad och tillverkning av svärdsskidor granskas. Problematik med bevarandeförhållanden diskuteras och alternativa sätt att studera ämnet utforskas. Slutsatserna av uppsatsen är att läderhantverk inkluderade många olika hantverkstekniker, som var spridda i hela samhället och praktiserades av vanligt folk. Flertalet explicita specialiseringar existerade dock också, vilket gav upphov till högkvalitativa läderprodukter. Slutligen ges förslag till framtida forskning.

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