Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

Rational design of natural leather-based water evaporator for electricity generation and functional applications

In recent years,water evaporation-induced electricity has attracted a great deal of attention as an emerging green and renewable energy harvesting technology.Although abundant materials have been developed to fabricate hydrovoltaic devices,the limitations of high costs,inconvenient storage and transport,low environmental benefits,and unadaptable shape have restricted their wide applications.Here,an electricity generator driven by water evaporation has been engineered based on natural biomass leather with inherent properties of good moisture permeability,excellent wettability,physicochemical stability,flexibility,and biocompatibility.Including numerous nano/microchannels together with rich oxygen-bearing functional groups,the natural leather-based water evaporator,Leather_(Emblic-NPs-SA/CB),could continuously produce electricity even staying outside,achieving a maximum output voltage of∼3 V with six-series connection.Furthermore,the leather-based water evaporator has enormous potential for use as a flexible self-powered electronic floor and seawater demineralizer due to its sensitive pressure sensing ability as well as its excellent photothermal conversion efficiency(96.3%)and thus fast water evaporation rate(2.65 kg m^(−2)h^(−1)).This work offers a new and functional material for the construction of hydrovoltaic devices to harvest the sustained green energy from water evaporation in arbitrary ambient environments,which shows great promise in their widespread applications.

How does bio-based leather become the favorite of luxury brands?

Artificial leather and synthetic leather products have more than 60 years of development history,because the cost of artificial leather is lower than real leather,the manufacturing process is relatively simple,widely used in textile,automotive and furniture decoration fields.

Covalent and Ionic Bonding between Tannin and Collagen in Leather Making and Shrinking:A MALDI-ToF Study

Collagen powder hydrolysates were reacted with a solution of commercial mimosa bark tannin extract.The mixture was prepared at ambient temperature and prepared at 80°C to determine what reactions,if any,did occur between the collagen protein through its amino acids and the polyphenolic condensed tannin.The reaction products obtained were analyzed by matrix assisted laser desorption ionization time-of-flight(MALDI ToF)mass spectrometry.Reactions between the two materials did appear to occur,with the formation of a relatively small proportion of covalent and ionic linkages at ambient temperature but a considerable proportion of covalent linkages tannin-protein amino acids and the disappearance of ionic bonds.The linkages between the two materials appeared to be by amination of the phenolic–OHs of the tannin by the amino groups of the non-skeletal side chains of arginine,and by esterification by the–COOH groups of glutamic and aspartic acid of the aliphatic alcohol-OH on the C3 site of the flavonoid units heterocycle of the tannin.The proportion of covalent linkages increases markedly and predominate with increasing temperatures.This tightening of the tannin-protein covalent network formed may be an additional contributing factor both to leather wear resistance and performance as well to leather shrinking when this is subjected to excessive temperatures.

Imperial Leather Original皂用香精的仿制

介绍了Imperial Leather Original皂用香精的特点及其香韵组成,详细叙述了如何运用不同香韵的单体原料仿配该香精的过程。讨论了香精的稳定性试验和三角试验。

Light-Dependent Properties of Finishing and Leather Defects

The uniformity of the colour in leathers for the furnishing and automotive sectors is a particularly important feature, especially for white or light-coloured articles, intended to the high-end market;on these articles any colour alteration can be very visible and unpleasant, with possible technical and economic consequences for the producers. In a previous study, we analysed the possible causes behind the formation of some peculiar pink/salmon stains on different kinds of white/beige/light-coloured leather furnishing items, where we focalized our attention on TiO2 properties and its possible interaction with some organic-based antioxidants. In recent years, due to many other similar cases of defects that occurred to tanners and to upholstery traders, we decided to enhance the investigations concerning this topic. More in detail we analysed, defective leathers, powder pigments and chemicals, in order to identify the possible role of some substances in this issue, with particular reference to some antioxidants and aluminosilicates, where several diagnostic techniques have been utilised, as ATR-IR (Attenuated Total Reflectance IR Spectroscopy), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis), XRF (X-ray Fluorescence spectrometry), GC-MS (Gas Chromatography-Mass Spectrometry), and DSC/TGA (Differential scanning calorimetry/Thermogravimetry) equipment.

Recovery Technology of DMF from Wet Type Polyurethane Synthetic Leather Waste Gas

A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6- 688.3 mg·m^-3, it was necessary to make sure two phases contact adequately and strengthen the mass transfer by increasing contact area and enhancing the turbulence. Therefore, two-stage countercurrent absorption and two-stage fog removing system were introduced into the technology. The top section of the absorption column was filled with structured wire-ripple stainless steel packing BX500, while the lower section with sting-ripple packing CB250Y. Total height of packing material was 6 m. In addition, there were both two-stage fog removing layer and high efficiency liquid distributor at the column top. All the operating parameters, including temperature, pressure, flow rate and liquid position, could be controlled by computers without manual operation, making sure the outlet gas achieved the national emission standard that the DMF concentration should be below 40 mg·m^-3. The whole equipment could recover 237.6 t of DMF each year, with the profit up to CNY 521×10^3.

Toward Enhancing Wearability and Fashion of Wearable Supercapacitor with Modified Polyurethane Artificial Leather Electrolyte

Inspired by the sophisticated artificial leather garment industry and toward enhancing wearability of energy storage devices, we demonstrate a polyurethane artificial leather supercapacitor with large sheet electrodes embedded in theleather layer simultaneously working as a polyelectrolyte. This design totally reserves textiles underneath and thus addresses the well-known challenge of wearing comfortability. It provides a revolutionary configuration of wearable supercapacitors: the artificial leather on garment is also a supercapacitor.Unlike the polyvinyl alcohol-based acidic electrolytes, which are widely used, sodium chloride is used to modify the intrinsically fluorescent polyurethane leather for ionic transportation, which has no harm to human. The fluorescent leather supercapacitor is easily transferrable from any arbitrary substrates to form various patterns, enabling multifunctionalities of practical wearability, fashion, and energy storage.

Biodegradation of Leather Waste by Enzymatic Treatment

The treatment of shavings,trimmings and splits of leather waste from tanneries has a potential to generate value-added products. In this study enzymatic treatment of leather waste was performed. This method utilizes alkaline protease produced by Bacillus subtilis in our laboratory by submerged fermentation. Optimum conditions of pH,time duration,temperature and concentration of enzyme were determined for maximum degradation of leather waste. The amount of degradation was measured by the release of amino acid hydroxyproline. Amino acid composition in the hydrolysate obtained by the enzyme hydrolysis was determined. This relative simple biotreatment of leather waste may provide a practical and economical solution.

Synthesis of Hyperbranched Polymers and Its Effect on Water Vapor Permeability of Microfiber Synthetic Leather

A series of hyperbranched poly(amine-ester)polyols were synthesized by the polycondensation of N,N-diethylol-3-amine-methylpropionate(prepared by Michael addition reaction of methyl acrylate with diethanolamine)as an AB2-type monomer with trimethylol propane as the core moiety,proceeding in one-step procedure in the melt with p-toluenesulfonic acid as catalyst.The obtained monomer and polymers were characterized by FTIR and 1H-NMR spectroscopy.The solubility and surface activity in aqueous solution of the polymers were also examined.The gas permeability,water vapor permeability,and moisture absorption of microfiber synthetic leather treated by hyperbranched polymer were studied.The optimum conditions were that the dosage of dye and hyperbranched polymer was 5% and 10%,respectively.The water vapor permeability and moisture absorption of microfiber synthetic leather reached to 0.525 4 mg/(10 cm2·24 h)and 0.046 7 mg/(10 cm2·24 h).Compared with blank samples,they increased by 15% and 35%,respectively.However,the dosage of hyperbranched polymer has little influence on gas permeability of microfiber synthetic leather.SEM results show that the fiber of microfiber synthetic leather treated by hyperbranched polymer is incompact.

Sucrose-free hawthorn leathers formulated with fructooligosaccharides and xylooligosaccharides ameliorate high-fat diet induced inflammation, glucose and lipid metabolism in liver of mice

High sucrose content in traditional hawthorn leathers limits the potential consumption, particularly for elders and diabetics. In this study, sucrose-free hawthorn leathers were formulated with 75% fructooligosaccharides(FOS) and 25% xylooligosaccharides(XOS)(HLF75), which exhibited comparable morphology and sensory properties to the traditional ones. Then, the anti-obesity activity of HLF75 was investigated using high-fat diet(HFD) fed C57BL/6J mice. Comparing with traditional hawthorn leathers, HLF75 supplementation in HFD significantly decreased the levels of blood glucose and serum lipid. The histomorphologies of liver and subcutaneous fat tissues were ameliorated by HLF75, as well as the down-regulated m RNA expression levels of IL-1β, Nos2 and Cox-2 in the liver. M oreover, the protein levels of M y D88 and NF-κB in the liver were suppressed by HLF75 treatment with decreased F4/80-positive macrophage number. Ho wever, the expression levels of PI3K, phosphorylated-AKT(Thr308), and phosphorylated-m TOR(Ser2448) proteins related to glucose metabolism were increased in the liver. Moreover, fat synthesis-related gene expression in HLF75-fed mice was suppressed while expressions of lipolysis genes were improved. Thus, HLF75 supplementation alleviated HFD-induced obesity through the alleviation of inflammation and restoration of the disturbed glucose and lipid metabolism. Functional oligosaccharides could be effective sucrose substitutes in hawthorn leathers and enable their potential utilization as functional foods.

MECHANICAL BEHAVIOUR OF NATURAL COW LEATHER IN TENSION

We study experimentally the microstructure and mechanical behavior of natural cow leather. Tensile tests are performed using leather strips to observe their deformation, creep and failure. It is found that the microstructure of cow leather is a layered, complicated network of fibers of different sizes from a few to a few hundreds of nanometers in diameter. They show nonlinear stress-strain relations and viscoelastic behavior. The effect of humidity is also examined. A simple theoretical model of a multilayered beam is proposed to describe the most basic behavior in tension.

Clean Production for Chrome Free Leather by Using a Novel Triazine Compound

Based on a novel triazine compound,the properties of tanned leather and commercial feasibility in pilot scale have been investigated.Then this novel approach tanning was compared with conventional chrome tanning:in the condition of less-salt pickling and chrome free,the physicochemical properties including thermal stability and mechanical strength were analyzed.Meanwhile,the surface roughness and fiber dispersion were evaluated as well.The results show that the thermal stability and mechanical strength of the triazine compound tanned leather are similar to conventional chrome tanned leather,the fiber bundle is well-dispersed and much evener than that of chrome treating.The optimized tanning approach has obvious reduction in environmental impact and leads an excellent biodegradability of tanning liquor.In industrial application,the cost of materials and water treatment are reduced effectively.The production of chrome free leather can encourage the sustainable development of leather industry and protects ecological environment in some extent.

Deformation Characteristics of Leather for Shoe Upper, Filled with Natural Minerals

A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.

Application of Cationic Waterborne Polyurethane as Impregnation Material for Microfiber Synthetic Leather Base

A cationic waterborne polyurethane(CWPU) was synthesized and utilized as impregnation material for manufacturing microfiber synthetic leather base,in an attempt to decrease environmental pollution associated with organic solvents and improve simulation degree relative to genuine leather.The alkali resistance of the CWPU and four manufacture methods were investigated.Meanwhile,the dyeing properties of the microfiber synthetic leather base were studied.It was found that the CWPU displayed enough alkali resistance to endure the alkali deweighting process for microfiber synthetic leather base manufacture.In terms of bending length,bending rigidity,compression elasticity ratio and specific compression elasticity ratio of the resulting base,coagulating the impregnated CWPU with sodium hydroxide before steam treatment was the optimal method.The extent of fiber splitting and the handle of the base from this method were both similar to conventional base filled with solvent-based polyurethane(SPU).The dyeing properties of the microfiber synthetic leather base filled with CWPU were also found superior to the one filled with either anionic waterborne polyurethane(AWPU) or SPU.

Genetic Algorithms to the Nesting Problem in the Leather Manufacturing Industry

The nesting problem in the leather manufacturing is the problem of placing a set of irregularly shaped pieces (called stencils) on a set of irregularly shaped surfaces (called leathers sheets). This paper presents a novel and promising processing approach. After the profile of leather sheets and stencils is obtained with digitizer, the discretization makes the processing independent of the specific geometrical information. The constraints of profile are regarded thoroughly. A heuristic bottom-left placement strategy is employed to sequentially locate stencils on sheets. The optimal placement sequence and rotation are deterimined by genetic algorithms (GA). A natural concise encoding method is developed to satisfy all the possible requirements of the leather nesting problem. The experimental results show that the proposed algorithm can not only be applied to the normal two-dimensional nesting problem, but also especially suitable for the placement of multiple two-dimensional irregular stencils on multiple two-dimensional irregular sheets.

Complete III Cranial Nerve Palsy in a Leather Worker: An Unusual Case Report

This case report describes features and surgical management in one patient that developed a worsening total III cranial nerve palsy in his right eye. Our 45 year-old male patient worked for about 25 years in leather tanning industry. He underwent medical history, routine blood test, eye exams that included visual acuity measurement, slit-lamp examination, dilated retinal biomicroscopy and indirect ophthalmoscopy, fundus photography, tonometry, corneal pachymetry, Krimsky test, oculomotor examination and eye deviation surgery. On examination of the fellow eye wasn’t found any disease. Stroke, aneurysm and intracerebral causes of third nerve palsy were excluded, and medical history was negative for diabetes, cardiovascular disease, trauma, neurological disease unless two previous polyneuropathies episodes and one herpetic keratitis episode. Result of any neuroimaging studies were recorded (Our patients performed in hospital CT, MRI and MRI angiography and all the testes were normal). To our knowledge third cranial nerve palsy has never been observed in literature in leather workers. In conclusion, it is important for ophthalmologists to evaluate carefully work history and lifestyle persons and plan the surgical approach focusing the different characteristics of these patients.

Eco-friendly Leather： Chromium Reduction in the Tanning Cycle

The leather manufacturing is traditionally responsible for high environmental pollution. Tannery effluent contains, indeed, large amounts of lime sludge, sulfides, acids, toxic metals salts, in particular chromium salts, which are toxic, non-biodegradable and hardly disposable. For this reason, great research efforts are addressed to establish a significantly eco-sustainable and convenient business for companies and to produce high quality leather products. The replacement of current commercial chemical and toxic products with innovative natural/naturalized products and technologies in some crucial phases of the tanning cycle （mainly bating and defatting）, can induce an eco-friendly reduction of the needed chromium amount. Leather samples, treated with innovative bating and defatting products and tanned by several different Cr contents, were characterized by SEM-EDS （Scanning Electron Microscopy equipped with Energy Dispersive X-Ray Spectroscopy） and TGA （Thermogravimetric Analysis）. SEM-EDS was used to observe the surface and cross-section morphology and to provide a semi-quantitative elemental analysis, while TGA to evaluate the thermal stability and decomposition phases. The compatibility of the innovative products was demonstrated and the environmental impact of the process, performed by the effluents characterization, was effectively improved as a result of a 20% Cr lowering. The use of innovative products and the chromium reduction did not affect the thermal stability, leather morphology and not involve significant differences in the composition.

Effect of the Morphology of Leather Surface on the Hydrophobic-Hydrophilic Properties

Natural leathers (split, velour split, nubuck) ware investigated. Solution of fluorine silane in ethanol was applied as the hydrophobic agent. It is shown that the microstructure of the leather surface, provided its structural elements possess hydrophilic properties, determines the wetting regime and duration of the induction period of changeover from heterogeneous to homogeneous wetting. The heterogeneous regime of wetting is distinguished by low rates of spreading and absorbing. The homogeneous wetting is characterized by high rates of spreading and absorbing of a water drop. A necessary condition of the stable heterogeneous wetting regime and achieving hydrophobicity of leather with structurally inhomogeneous face layer is to preserve the microstructure features of their surface at hydrophobic treatment. The morphological peculiarities of split and ground leather ensure stable hydrophobic properties after application of efficient hydrophobizators.

Shanghai Leather Corporation

The Shanghai Leather Corporation has a production and export history of 40 years. It possesses 32 factories, 17 joint ventures, a research institute of the leather industry and a school for staff and workers. Its factories and joint ventures belong to the three trades, of leather processing, shoe making and leather product making, as well as other trades of chemicals, rubber, hardware and shoe tree production that relate to leather-product manufacture. Its major exports include leather shoes, sports shoes, various gloves, footballs, basketballs, volleyballs, leather garments, leather purses, suitcases and bags. These sell well in dozens of countries and regions, such as Europe, the United States,