Gelatine-modified Zn-Al layered double hydroxide (GLDH) was synthesised by co-precipitation to develop an effective, environmentally compatible flame-retardant system for leather. The resulting GLDH and the precursor materials (gelatine and Zn-Al LDH) were characterized by zeta potential, hydrodynamic diameter, crystallographic phase(s), functional groups, and thermal analysis. The GLDH exhibited crystallographic phases typical of LDH, gelatine, and hydrozincite (ZnO), confirming the successful incorporation of gelatine in the LDH matrix. Pristine LDH and GLDH were applied to leather to assess their influence on the flammability performance of leather. Horizontal flammability tests showed a reduction in burning rate by 9.1% for LDH-treated leather and 23.5% for GLDH-treated leather. The enhanced performance of GLDH is attributed to the synergistic effect of gelatine incorporation, which promotes char formation and improves thermal shielding in addition to the endothermic dehydroxylation and decomposition mechanism of the LDH. These results indicate that gelatine-modified LDH can be a promising, environment-friendly flame-retardant additive for leather.
Crunch leather is a special class of leather that exhibits a double-tone effect on the surface due to the migration of oil within the leather surface. In this study, extracted fat has been used in place of oil to get crunch leather. The fat was extracted from cow, buffalo, sheep, and goat and characterised. Due to high fat content, sheep fat was specifically selected for use in the finishing process as an alternative to traditional oils in the making of crunch leather. The experimental leather preparation involved mixing sheep fat with a Beeswax emulsion at 80 degrees C in varying ratios. These experimental leathers were compared with control leathers treated with carnauba wax to assess differences. The physical properties of the experimental leathers were found to be on par with those of the control leathers.
In the quest for eco-friendly and sustainable substitutes for traditional petroleum-based polyurethane (PU) dispersions for leather finishing, this work explores the application of bio-based waterborne polyurethane dispersion (BPUD) prepared from cardanol-based polyols for typical resin finishing in comparison to the performance of a commercial petroleum-based PU dispersion (PPUD). Two formulations were studied namely a mixture of BPUD with an acrylic resin binder at 1:1 ratio and the other using BPUD alone (2:0 ratio) and various performance properties such as film adhesion, color fastness, water vapor permeability, hydrophobicity, and gloss were analyzed along with structural properties. Physicochemical characterization showed that BPUD has a lower particle size and similar viscosity compared to PPUD. The structural features of the leather, namley grain surface and fiber structure, were not altered significantly when PPUD is substituted with BPUD as seen through scanning electron microscopy. Most importantly, BPUD exhibited better film adhesion in dry and wet environments, increased water vapor permeability (4.9 mg/cm(2).Hr compared to 3.09 mg/cm(2).Hr for PPUD based finishing), and matching hydrophobicity and gloss, especially in the resin-free variant. Color fastness against rubbing and light was slightly lower in the absence of resin, but total performance confirms the viability of BPUD as a good petrochemical-based PU alternative. These results highlight the significance of bio-based dispersions in environmentally friendly leather processing and pave the way for the continued development of biodegradable and sustainable PU systems.
Traditionally, 50% w/w sodium chloride (NaCl) is employed for hides and skin preservation (curing). However, enormous water pollution, aquatic toxicity, soil infertility, and high chemical consumption make it questionable. Leftover and abundant plant biomass can be a sustainable alternative source of curing if they keep antimicrobial activity against hides and skin spoilage microorganisms. This study investigates biomass-based curing (BBC) from Cynodon dactylon and Albizia lebbeck plant independently and collaboratively. The plant's dry powder was directly applied and evaluated curing efficiency through bacterial load, moisture content, hydrothermal stability, and hydroxyproline content assessment. The BBC formulations were easy to use and showed high biomass conversion efficiency, reaching 41% for C. dactylon and 53% for A. lebbeck based on raw weight. They also exhibited strong antimicrobial activity. C. dactylon showed inhibition zones of 18 mm against E. coli and 17 mm against B. subtilis in methanol extracts. A. lebbeck showed a 17 mm zone of inhibition against E. coli in both ethanol and methanol extracts, and a 15 mm zone against B. subtilis in ethanol extract. In addition, the BBC formulations successfully preserved goatskin for 30 days, performing comparably to the conventional preservation method. It lessened the salinity, total dissolved solids, and chemical oxygen demand load from tannery-soaking effluent by 67-74%, 41-65%, and 60-85%, respectively, through the maximum reduction of salt consumption (90%). The environmental efficiency index (EEI) revealed that BBC systems (EEI: 29.9-31.3) are around 1.5 times more environmentally sustainable than conventional curing (EEI: 20.7). In addition, the alternatives have no effect on the features of final leather. Therefore, the ecofriendly BBC has the potential to prevent the generation of heavy pollution from tanneries.
Diabetic foot (DF) disease can involve both monomicrobial or polymicrobial infections. The emergence of antibiotic-resistant strains in DF has been attributed to the recurring nature of infections and the use of antibiotics by patients. In some cases, these strains have been observed to form biofilms, which can significantly complicate the progression of the disease. Shoes are very important for patients of DF. In this regard, the importance of natural compounds that can be integrated into shoes/insoles that DF patients can use is emphasized in the literature. Lichens have very important bioactive components that are not even found in plants, and these compounds have many properties such as antimicrobial, antibiofilm and antioxidant. This study aimed to investigate antibacterial, antibiofilm and antioxidant properties of acetone extracts obtained from tested lichens against DF isolates. The lichen species examined were P. furfuraceae, H. physodes, and Usnea spp., and the isolates analyzed included S. epidermidis, A. baumannii, A. pittii, P. aeruginosa and K. pneumoniae, which were isolated from DF patients. Lichen acetone extracts were found to have low antibacterial activity (below 50% inhibition) against only A. baumannii and S. epidermidis. However, with consideration of the antibiofilm effect of the extracts, a more promising outcome was observed than in terms of antibacterial activity. Noteworthy antibiofilm activity was exhibited by lichen extracts, particularly against S. epidermidis (approximately 97%) and subsequently against A. pittii (between 92.61- 80.59%) at the 800 mu g/mL. Even at a concentration as low as 25 mu g/mL, the acetone extracts of P. furfuraceae, H. physodes, and Usnea spp. inhibited biofilm formation of S. epidermidis, with inhibition ratios of 92.95%, 94.74%, and 96.43%, respectively. Moreover, high biofilm inhibitory effects with the percentages of 87-90% were detected against K. pneumoniae even at low concentrations. The findings of this study demonstrate that acetone extracts from the tested lichen species exhibited a high antibiofilm efficacy of over 80% against DF isolates. It is important to consider the capacity of lichens to prevent the formation of biofilms by microorganisms that develop on the feet of diabetic patients. The incorporation of these materials into footwear in the leather industry may provide an additional benefit of combating persistent microorganisms.
Wet-blue hides are a critical intermediate product in the leather manufacturing process, and their surface defects can significantly affect the final leather quality and market value. To improve the quality and efficiency of modern leather production, this paper proposes an efficient and accurate surface defect detection model for wet-blue hides, named SCSAB-Net, based on an optimized You Only Look Once version 8 (YOLOv8) architecture. To enhance the model's ability to accurately identify defects against similar textured backgrounds, Spatial and Channel Synergistic Attention (SCSA) mechanism is integrated into the backbone network, guiding the model to focus on defect-relevant regions while suppressing background interference. In the feature fusion stage, a lightweight weighted bi-directional feature pyramid network (DSC-BiFPN) is designed, incorporating depthwise separable convolutions (DSC) to improve multi-scale feature fusion while reducing computational complexity. Furthermore, the Scylla Intersection over Union (SIoU) loss function is introduced to optimize bounding box regression, enabling more precise and efficient localization. To evaluate the model's performance, a dedicated dataset was constructed for wet-blue hides defect detection, covering three categories: brands, broken holes, and broken surfaces. Experimental results demonstrate that the proposed model achieves detection accuracies of 86.4%, 98.6%, and 89.4% for brands, broken holes, and broken surfaces, respectively, thereby effectively balancing the industrial demands for both high accuracy and efficiency in surface defect detection tasks.
Anchor-point planning on closed contours is a core challenge in the automation of flexible materials, where performance hinges on jointly accounting for local geometric features, global uniformity, and operational safety. This paper presents P-WEP, a practical framework for engineering deployment of weighted equal-mass partitioning. Centered on the WEP-CC theory, the framework uses a log-linear (product-form) density fusion to unify priors of curvature magnitude, radial protrusion, and outer-edge indication. A morphological safety inward offset (M-SOC) is introduced to realize a calibratable safety boundary at the pixel scale. On top of this, a one-dimensional phase-aligned refinement (phi-VE) searches along the mass axis to substantially reduce geometric residuals without compromising the equal-mass property. To avoid self-evaluation bias, we establish an aligned dual-metric protocol computed on an independent assessment curve: the weighted equal-mass error (MassErr) and the contour-distance root-mean-square residual (CD-RMS). Experiments on 10 real leather contours show that, compared with equal-arc-length and single-component-density baselines, WEP-CC+phi-VE achieves CD-RMS of 0.2366 +/- 0.0408 (down from approximate to 0.55-0.60; approximate to 57%-59% average reduction; standard deviation reduced from approximate to 0.26 to 0.04), while MassErr further improves by approximate to 4.2% over WEP-CC with lower variance. Ablation studies indicate that removing M-SOC increases CD-RMS by approximate to 109%; removing any single density component increases CD-RMS by approximate to 93%-102%; and removing phi-VE only mildly affects MassErr yet raises CD-RMS by +8.8%, confirming that "density fusion + safety boundary + phase alignment" is critical to performance and stability. Overall, P-WEP preserves near-linear complexity and interpretability while jointly ensuring feature preservation, global uniformity, operational safety, and stable geometric fitting, offering a transferable and reusable end-to-end solution for leather stretching and other flexible-sheet applications.
Syntans are widely used in leather making. They are made from fossil-based phenol and formaldehyde. Both building blocks are toxic. Many syntans currently have high values of bisphenols, some have a problem with rest-monomeric formaldehyde. This is why the search is ongoing for re-tanning agents made from less toxic and preferably renewable starting materials, that can substitute for syntans avoiding formaldehyde and bisphenol issues. In this article novel condensates are introduced that are obtained by condensation of dicarboxylic esters with renewable aromatic aldehydes. A subsequent reaction leads to complete water solubility. A preferred aromatic aldehyde is vanillin, which is commonly used in nutrition, avoiding any toxicity issue. Vanillin can be obtained from a waste stream of the paper industry. In application on leather, these novel condensates could achieve or outperform the performance of syntans and vegetable tanning agents in re-tanning concerning softness, fullness, and fastness properties. No formaldehyde was used in the condensation, no bisphenols formed. The synthesis is facile and dominantly renewable starting materials were chosen as building blocks. These results have been presented at the 12th Ledertage conference in Salzburg, Austria in June 2024. Additionally, this article will present for the first time, results of the application of these condensates in sole tanning
Proteolytic halotolerant Bacillus species that may adversely affect leather quality are the predominant bacteria found in the curing salt samples used in the leather industry. Therefore, this study aims to examine the growth of 83 proteolytic halotolerant Bacillus isolates (B. amyloliquefaciens, B. atrophaeus, B. halotolerans, B. licheniformis, B. mojavensis, B. paralicheniformis, B. pumilus, B. safensis, B. siamensis, B. subtilis, B. tequilensis, B. velezensis) recovered from 30 salt samples at different temperatures, pH values, enzymatic activities, utilization of carbon and amino acid sources, antibiotic resistance profiles of these species against medically important antimicrobials and the inactivation effect of 1 A (amp) direct electric current (DC) on a mixed culture of proteolytic and lipolytic halotolerant Bacillus isolates in a brine solution with 0.85% NaCl. All Bacillus isolates grew between 20-45°C and pH 6-7. Most isolates grew at pH values ranging from 5 to 10. None of the Bacillusisolates grew at pH 4, 5°C, and 65°C. All salt samples contained Bacillus isolates with multiple hydrolytic enzymes. All test isolates produced caseinase enzyme. Although most Bacillus isolates produced cellulase, amylase, β-galactosidase, and xylanase, some Bacillus isolates produced urease, lipase, deoxyribonuclease, and pullulanase enzymes. While all Bacillus isolates utilized glucose, sucrose, and L-methionine, most isolates used ribose, L-cysteine, L-hydroxyproline, L-alanine, L-aspartic acid, L-isoleucine, glycerol, lactose, L-histidine, L-arginine, L-glycine, L-valine, L-leucine, L-glutamic acid, L-phenylalanine, and galactose. In addition, L-lysine, L-proline, L-tyrosine, L-serine, and L-threonine were used by some test isolates. Amino acid utilization test results showed that when the proteolytic enzyme of Bacillus isolates breaks down the collagens into amino acids, these isolates can use amino acids as nutrients to grow and subsequently damage salted skins. Multidrug-resistant Bacillus isolates, exhibiting resistance to three to six antibiotics, were common in the curing salt samples. Resistances of Bacillus isolates against vancomycin (5 µg) and erythromycin (15 µg) were found to be high. Resistances against clindamycin (2 µg), norfloxacin (10 µg), ciprofloxacin (5 µg), and levofloxacin (5 µg) of some isolates were detected. A 1A DC treatment killed the mixed culture of multidrug-resistant proteolytic halotolerant Bacillus species with high catabolic activity at a voltage level of 10.9 V within 25 minutes. In conclusion, the examination of phenotypic characteristics, and antibiotic resistances of proteolytic halotolerant Bacillus species revealed potential characteristics of Bacillus species that can cause adverse effects on skin quality. Therefore, the extermination of the multidrug-resistant proteolytic and lipolytic halotolerant Bacillus species with high catabolic activities via the 1A DC process is very important to prevent both contamination of hides and skins with these Bacillus isolates during salt curing processes and the development of antimicrobial resistance and spread on salted skins and hides in the leather industry.
Hides and skin preservation has been prominently undergoing salt curing technique for centuries which uses high amount of NaCl (40%) that causes huge amount of total dissolved solids (TDS) and salinity in soaking wastewater of leather processing. Recently, Phyto based preservation is getting emphasis due to being sustainable with less environmental impact. In this study, Gossypium hirstum (cotton) seed powder (5%-7.5%) with 10% salt were applied as a novel source for goatskin preservation. Curing efficiency was monitored by checking organoleptic and physiochemical properties (moisture content, shrinkage temperature, bacterial count, nitrogen content, etc.) at regular intervals. Accomplishing the preservation period, preserved skins were processed into shoe upper leather. The pollution parameters were checked from soaking waste liquor to evaluate the environmental impact. SEM analysis and physical properties were evaluated to check the quality of the produced shoe upper leather. The results revealed that newly developed preservative can preserve goatskin for up to 28 days without any deterioration. Experiments reduced pollution by lowering chloride levels 65.33%-66.91%, total dissolved solids by 41.06%-35.2%, biochemical oxygen demand by 30.86%-34.28% percent, and chemical oxygen demand by 41.06%-35.2%. According to the correlation study, there were significant dependencies between the goatskin preservation efficacy parameters, with strong correlation (r = − 0.976, p<0.001) found between shrinkage temperature and moisture content. Surface topography and physical strength of the produced leather was comparable to conventional shoe upper leather. Thus, the introduced seed powder could be one of the valuable sources of eco-friendly leather preservation to reduce environmental pollution
To address the mismatch between complex development requirements and traditional design efficiency in the era of artificial intelligence, a footwear innovation design method based on generative artificial intelligence is proposed, using athletic footwear as a case study. Through human-machine collaborative analysis of category products and user demand surveys, a hierarchical model comprising 4 primary indicators and 17 secondary indicators is constructed. The weights of various elements are calculated, and consistency testing was refined to transform vague user demands into specific design prompts. Using generative artificial intelligence technology to assist in footwear innovative design, through the trend matching, adversarial training, parameter optimization, noise generation and other steps to complete the preliminary design proposal. This proposal was optimized and practiced on the modeling software platform to verify its feasibility. Finally, the design proposal was evaluated for comprehensive satisfaction from four dimensions: color attributes, style attributes, material attributes, and functional attributes. The results indicate that the paradigm, derived from this method, offers significant practical value and provides research insights and methodological guidance for footwear design
Xiaoliang Mountain Yi embroidery represents a significant subcategory of Yi ethnic embroidery, characterized by a long historical tradition and distinctive handcrafted techniques. Women's boots, a staple footwear choice for female consumers during the autumn and winter seasons, have historically failed to satisfy the growing demand for personalization. This shortfall stems from a lack of innovation and the insufficient incorporation of traditional ethnic cultural elements, which are largely absent from most boots on the market. As a key medium for conveying artistic and cultural significance, Xiaoliang Mountain Yi embroidery patterns embody the profound heritage of traditional ethnic culture. Integrating these patterns into innovative women's boot designs imbues the products with unique stylistic attributes. This paper proposes a modernized application design process for traditional patterns, leveraging Kansei engineering and shape grammar to quantify consumer affective evaluations of Xiaoliang Mountain Yi embroidery patterns. The most popular patterns, as identified through consumer evaluations, are further refined using shape grammar and innovatively applied to women's boot designs. The findings reveal that employing Kansei engineering to analyze consumer affective responses provides a scientific and data-driven foundation for pattern innovation. Moreover, the creative application of Xiaoliang Mountain Yi embroidery patterns enhances the distinctiveness of women's boots, offering valuable insights and actionable strategies for designers and brands in the women's footwear market.
The key point for enzymes to effectively play their roles in the enzymatic animal hide/skin collagen purification processing is to pass through the diffusion barriers and evenly disperse in the hide/ skin. Enzyme and collagen proteins can dissociate and adsorb H+ to generate surface charges at the solid-liquid interface of animal hides/skins. The surface charge interaction between the enzyme and the hide/skin is an important factor affecting the mass transfer of enzymes into animal hides/skins. In this review, the structure, composition and charge characteristics of the permeation channels, the generation mechanism of surface charge at the solid-liquid interface, and the factors that affect the surface charge between enzymes and permeation channels were summarized. Especially, the surface charge interaction between the enzymes and the micro nano permeation channels was first highlighted. In addition, the application of charge regulation methods to enhance the permeability of enzymes into the animal hide/skin was introduced, and new ideas were put forward to reduce the resistance of solid-liquid interface charge for achieving rapid mass transfer and uniform diffusion of the enzymes. This review has great guiding significance for enzymatic animal hide/skin collagen purification and the preparation of collagen -based raw materials.
Leather products usually undergo special finishing treatments to protect them from damage and mask any imperfections in their appearance, guaranteeing a polished and premium -quality outcome. Green coating materials are in urgent need with ever-increasing environmental protection consciousness. The resins used to produce leather coatings are required to be derived as much as possible from bio-based materials. Addressing this challenge necessitates the creation of a novel bio-based coating that boasts excellent water resistance, adhesion, and mechanical strength. This research focused on developing polyols from bamboo powder, concurrently synthesizing a range of bamboo powder-based waterborne polyurethanes (BWPU) using isophorone diisocyanate (IPDI) and polytetramethylene glycol (PTMG2000) as the key monomers. The results revealed a remarkable improvement in water resistance, adhesion, and mechanical strength with an increase in the bamboo powder polyols concentration. Notably, the film demonstrated the most optimal overall properties when the bamboo powder polyol content was 4 wt%. Specifically, the BWPU4 film exhibited a water absorption rate of 6.13%, a tensile strength of 16.34 MPa, and a significant increase in adhesion force, reaching 43.6 N/cm. This innovative approach was expected to present new avenues for the leather industry to embrace renewable resources and minimize its environmental impact.
Fatliquoring is an important process in leather production, which is helpful to improve the mechanical properties and sensory properties of leather, especially the softness. However, in recent years, with the urgent demand and rapid development of chrome-free tanning technology, the traditional fatliquoring agents and fatliquoring processes designed to adapt to chrome tanning technology are no longer compatible with these new tanning technologies and usually face the problems of low fatliquoring absorption rate, uneven distribution and poor binding ability. In order to better promote the integrity and commercial exploitation of chrome-free tanning technology, some fatliquoring agents and corresponding fatliquoring processes suitable for chrome-free tanned leather have been developed. This review summarizes the recent progress of fatliquoring technology suitable for chrome-free tanned leather. The properties of chrome-free tanned leather, the characteristics of different fatliquoring agents, the fatliquoring process parameters, and their influence on the fatliquoring process of chrome-free tanned leather are emphatically discussed. Furthermore, the characterization methods of fatliquoring effect are also introduced from the aspects of absorption, distribution and biodegradability of fatliquoring agent and fatliquoring mechanism. Especially, the problems faced by fatliquoring technology of chrome-free tanned leather aredescribed, and its future development direction is prospected.Finally, the reasonable assumption of fatliquoring agent and expected fatliquoring effect suitable for chrome-free tanned leather based on silicon materials developed by our group is put forward.
Pre-tanning agents can alter collagen and improve the efficiency of chrome tanning in the leather industry. In this work, tragacanthin (TRG) was separated from gum tragacanth (GTR) and oxidized by hydrogen peroxide (OTRG). The possible use of OTRG as chrome absorbent was evaluated before using it as a pre-tanning agent. The results showed the 96.7% chromium absorption from solution. After that, the OTRG was used for chrome uptake, resulting in high chrome exhaustion (90.71%) and high shrinkage temperature (Ts=114 °C) over the conventional chrome tanning. The SEM images of wet-blue revealed the dispersed collagen fibers. The use of pre- tanning agents significantly enhances the mechanical properties of leather. With tensile strength of 301.53 kg/cm², elongation at break of 47.02%, and tear strength of 50.11 kg/cm, these improvements indicate that the pre-tanning process effectively contributes to the durability and flexibility of the final leather product. This enhancement not only improves performance but also expands the potential applications of leather in various industries. So, TRG, being a natural polysaccharide, can function as a pre-tanning agent for high chrome exhaustion.
The leather sector is a by-product utilizer of the meat industry which makes use of animal skin as the raw material for further value addition. The processing of animal skin into value added leather material involves a series of operations and processes which leads to the generation of different types of wastes. These waste materials are often hard to treat and manage in an industrial scale. One such waste is the raw trimmings, which are generated through the beamhouse operations of leather processing. The raw trimming waste generated in the beamhouse is rich in proteins namely collagen and keratin. The current study focuses on the development of single step process technology to utilize the raw trimmings by means of alkali hydrolysis. The resultant Cocktail Protein Solutions (CPS) has shown antioxidant properties of 38-58%, increase in activity with decrease in the alkali concentration. The foaming capacity found to increase with alkali concentration however the foaming stability declines at higher alkali concentration. The cocktail protein solution was combined with natural biopolymers to prepare bio-composite products such as sheets and films. The prepared bio-composite sheets showed tensile strength of 1.45 N/mm2 and tear strength of 6.38 N/mm. A simple and effective method has been developed to transform raw trimming waste into valuable material for footwear and other applications, promoting a circular economical initiative.
