The deformation and force-bearing processes of leather in drum during tanning were investigated under different rotating speeds. The complicated deformation process of leather in drum was first simplified to a periodic process from a circle to an oval, and the calculation model of deformation was established. Then the deformation and force-bearing processes of leather in the drum were quantitatively validated through visualization experimental data. It was proven that this model was scientifically sound. Moreover, using high speed (such as 15 r/min in this experiment) at the beginning of tanning and low speed (such as 5 r/min in this experiment) at the end of tanning can result in large deformation and pushing force of leather, thereby benefiting the mass transfer of leather chemicals and enhancing tanning performance. The obtained results are expected to improve the energy conservation of leather industry.
Collagen was extracted from zeolite and TWS tanned waste leather chips using the dilute acid method, and the extraction process was optimized using the extraction rate and characteristic viscosity number as indexes, and the purified collagen hydrolysates were characterized. Subsequently, the collagen hydrolysate extracted from TWS-tanned waste leather chips (C-TWS) was blended with polybutylene terephthalate (PBAT) to form films, and the film-forming properties of the mixture were investigated. Results show that the two collagen hydrolysates contained 17 amino acids, and the elemental composition was dominated by C, N, and O with low mineral salt content, and they are high-quality biodegradable protein substrates. The blending process of PBAT/C-TWS was a simple physical blending one, and the increase of C-TWS content could lead to the increase by 43.05%-182.5% in the water vapor transmission rate of the composite film. When the content of C-TWS component was 30%, the maximum thermal degradation temperature of the resulting film was reduced from 405.4 ℃ to 386.5 ℃, and all the proportions of the blended films had good light transmittance. The blended system had better compatibility when the content of C-TWS component was less than 50%.
Polydopamine-coated MXene (MXene@PDA), a photothermal conversion material, was introduced into collagen aerogel to improve its photothermal conversion ability and expand its application in the field of low temperature protection. MXene was prepared by chemical etching and in situ lithium-ion intercalation, and then the oxidative self-polymerization reaction of dopamine (DA) on the surface of MXene was utilized to obtain MXene@PDA. Moreover, the effect of DA dosage on the properties of MXene@PDA was explored. The structure and properties of MXene@PDA were tested and characterized using transmission electron microscopy, scanning electron microscopy, X-ray diffraction and ultraviolet-visible-near infrared spectroscopy. Results showed that PDA was successfully coated on the surfaces of MXene flakes, which improved the environmental stability of MXene. The best light absorption performance of the fabricated MXene@PDA was achieved when the mass ratio of MXene to DA was 100∶6. Under the irradiation of 100 mW/cm2 xenon lamp, the temperature of MXene@PDA modified collagen aerogel was as high as 54.8 ℃, which was enhanced by 17.9 ℃ compared with pure collagen aerogel, and the maximum temperature was around 54.8 ℃ in several photothermal cycling experiments, showing the excellent photothermal conversion performance and cycling stability.
In order to improve the utilization value of wool fiber in tannery solid waste, this work combined the membership degree comprehensive analysis method with the response surface optimization method to establish the enzymatic recovery process of wool fiber. The membership degree comprehensive analysis method was used to calculate the whiteness, breaking strength, elongation at break, total protein and total sugar content of wool fiber recovered by different enzymatic methods. The comprehensive score S was used as the response value, and the response surface optimization method was used to optimize the ratio of enzyme preparation. Finally, the recovery process of wool fiber was obtained. Specifically, the wool-containing leather solid waste was immersed in a high-temperature water bath at 80 ℃ for 1 h. After cooling, it was immersed in a solution containing 2.5 g/L collagenase, 2.5 g/L trypsin, and 5 g/L bromelain. The pH was adjusted to 7.0 by using NaOH solution, and the enzymatic hydrolysis was performed at 40 ℃ for 5 h. The whiteness of the extracted wool fiber was 61%, and the elongation at break of the fiber was 33%, which was higher than that of the raw wool. The breaking strength of the fiber was 1.08 cN/dteX, which was 96% of the raw wool. This study provides a theoretical reference for the high value research of leather wool solid waste.
In order to achieve precise localization of leather grasping points by robots, this study proposed an improved approach based on the YOLOv5 algorithm. The methodology involved the integration of the coordinate attention mechanism into the Backbone layer and the replacement of the CIOU Loss with the Focal-EIOU Loss to enable different gradients and enhance the rapid and accurate recognition and localization of leather grasping points. The positioning coordinates of the leather grasping points were obtained by using the target bounding box regression formula, followed by the coordinate system conversion to obtain the three-dimensional coordinates of the target grasping points. The experimental positioning of leather grasping points was conducted by using the Intel RealSense D435i depth camera. Experimental results demonstrate the significant improvements over the Faster R-CNN algorithm and the original YOLOv5 algorithm. The improved YOLOv5 algorithm exhibited an accuracy enhancement of 6.9% and 2.63%, a recall improvement of 8.39% and 2.63%, and an mAP improvement of 8.13% and 0.21% in recognition experiments, respectively. Similarly, in the positioning experiments, the improved YOLOv5 algorithm demonstrated a decrease in average error values of 0.033m and 0.007m, and a decrease in error ratio average values of 2.233% and 0.476%.
Standards offer the technical support for economic activities and social development, which is an important aspect of the country's foundational systems. Standardization must play a leading and exemplary role during the process of achieving carbon peaking and carbon neutrality goals, namely "dual carbon goals", in leather field. In this work, the policy orientation, current standard system, and green and low carbon development trend for leather industry are comprehensively analyzed firstly. Then the framework of "dual carbon goals" standard system adapt to leather industry is proposed. Finally, three suggestions are put forward, i.e., speeding up the formulation and revision of basic general standards, increasing the supply of group standards and strengthening the standard publicity and training, in order to promote the implementation of the standardization work for achieving carbon peaking and carbon neutrality in leather industry.
Leather machinery is an important support for the progress of leather industry. The invention of drum is the most important achievement of wet tannery operation to water saving and high efficiency, so that the drum has also become the most critical equipment to complete the chemical process of tanning. Because the circular suspension drum has a fixed moving trajectory, different processing effects of hide or crust need to be changed through the adjustment of the internal structure and operating parameters of the drum. Herein, the common action characteristics of drum on hide or crust were analyzed and some correlations between the internal structure of the drum and the operating parameters of the tanning process were described, which include the influence of the resulting mechanical action such as kneading, extrusion and stretching on the dissolving out of the materials in the hide or crust and the infiltration of the external materials.
The thermal and wet comfort of cold-proof shoes is important for people living in cold areas. In this study, the literature related to the heat and humidity comfort of cold-proof shoes was searched in the Chinese and English databases such as CNKI, Web of Science, etc. This paper summarized the related contents about the thermal-moisture comfort and thermal-moisture coupling effect of shoes in the literature, and found that there was a lack of relevant contents of thermal-moisture coupling on shoes in the past research. Therefore, this paper summarized the winter shoes' thermal-moisture interaction in cold environment in order to provide reference for the study of the winter shoes' thermal-wet comfort.
Microfiber synthetic leather is an ideal material to replace natural leather, but its water vapor permeability performance is still far from that of natural leather. The process of preparing microfiber leather was discussed in this paper, and the properties of microfiber leather and its deficiencies in water vapor permeability were analyzed. Specifically, the progress of research on the water vapor permeability of microfiber leather was discussed from the two main components of microfiber leather, namely microfiber leather base fabric and polyurethane resin. The modification of microfiber leather base fabric by hydrolysis, the addition of reactive groups and hydrophilic agents was summarized. The modification of polyurethane resin by filler, graft polymerization and co-blending was also discussed. Moreover, the modification of microfiber leather by finishing was discussed. Finally, the research direction for the water vapor permeability of microfiber leather was proposed.
The purpose of this article is to describe the industry status of shoes for the elderly. We analyzed the domestic standards, various supervision and spot check data, and public opinions about the industry of shoes for the elderly, summarized and concluded the source of quality problems of the elderly shoes products, and carried out the related risk analysis. Suggestions were put forward for the improvement of the risk control mechanism of the elderly shoes products from the aspects of relevant functional departments, production enterprises and consumers, which will aim to improve the quality of the elderly shoes products.
Oxidized rapeseed oil was sulfited by sodium bisulfite and neutralized by triethanolamine to obtain a vegetable oil-based fatliquoring agent (OSF-T). The low iodine value fatliquoring agent (OSF-PT) was then obtained by adding peracetic acid to remove residual sulfite. The two fatliquoring agents were applied to the fatliquoring experiment of cowhide wet blue, and their performance was compared with that of the commercial fatliquoring agent AMK. Results showed that both OSF-T and OSF-PT emulsions exhibited particle sizes ranging from 10 to 180 nm, which were smaller than that of AMK. Furthermore, OSF-T and OSF-PT exhibited excellent emulsion stability and dispersibility. Their fatliquoring performance was good. The softness of OSF-T fatliquored leather can reach 6.5 mm, and the content of volatile organic compounds (VOC) was 123.7 g/m2. The VOC content of OSF-PT fatliquored leather was 121.3 g/m2. The VOC contents of the above samples were lower than that of the commercial products (164.3 g/m2). The color of black OSF-PT fatliquored leather was lighter than that of AMK fatliquored leather, and the color difference (ΔE ) was 4.12. OSF-PT was more suitable for light leather fatliquoring. After thermal aging and ultraviolet aging treatments, the tensile strength of OSF-T fatliquored leather remained above 15 MPa, and the content of hexavalent chromium was less than 5 mg/kg. Fatliquoring agent OSF-T was slightly better than the commercial fatliquoring agent AMK in terms of softness, mechanical properties, aging resistance and hexavalent chromium content.
Collagen peptide/Methyl vinyl silicone rubber（MVQ） composites were prepared by adding biomaterial collagen peptide to MVQ using double-roller mill. The results showed that collagen peptide had the effects of structure control agent and delayed vulcanization. With the increasing of the amount of collagen peptide,the composite's hardness increased, and the 100% tensile stress was improved from 1.92 MPa to 2.66 MPa, but its tensile strength and tear strength decreased. When the collagen peptide content was 4 per hundred of rubber, the maximum thermal weight loss rate temperature of the composite was 1.6% lower than that of MVQ. The characteristic peaks of MVQ and collagen peptide appeared in the infrared spectrum of the composites, and the hydrophilicity had been improved to a certain extent. The contact angle decreased by 4.5% at 4 per hundred of rubber.
With the increasing personalized demand in the garment consumption market, leather garment design is becoming increasingly diversified. Based on the excellent plasticity of leather fabrics and the advantages of natural materials, a series of practical explorations were carried out by exploring the three-dimensional space of garment and combining the leather sculpture technology. According to the experimental results, it is found that in the sculpture molding, sculpture resin is suitable for the small area, small volume, and less detailed forms, while the water-based sculpture clay is suitable for the large area and large volume shaping. In terms of leather material selection, the thick vegetable-tanned goatskin is suitable for the large area of simple and stiff styling; the slightly thinner vegetable-tanned goatskin is easier to shape the curve of large curvature; the soft and thin sheepskin has obvious advantages in completing complex structures. After the shaping treatment, the resulting leather can meet the requirements for clothing space shaping, and its excellent performance and texture are greatly beneficial for the three-dimensional expression of leather sculpture garment.
This paper explored the distribution pattern of plantar pressure in healthy young people of Tibetan and Han nationality in the plateau and compared the differences in the plantar pressure characteristics between the two nationality groups, which provides basic data for constructing a gait database for plateau populations. Using the Italian MPS plantar pressure testing system, plantar pressure tests were conducted on 160 selected healthy young people residing and migrating to high altitude in Tibet University, and the obtained data were statistically analyzed. The results are as follow: (1) there are differences in male contact area, female peak pressure, average pressure, and arch index between nationality groups when standing (P<0.05), and there are differences in female contact area and foot axis angle between nationality groups during walking (P<0.05). (2) There are differences in male contact area (Toe1,Toe2-5, Meta5), peak force (T1, T2-5, Meta2), peak pressure (Mid Foot) and impulse (T1,T2-5, Meta1, M2, Meta3, Meta4, M5) among nationality groups (P<0.05), and there are differences in female contact area (T1, T2-5, M4, M5, Medial Heel, Lateral Heel), peak force (T1, T2-5, M2), peak pressure (T1, M1, M4), average pressure (T1, T2-5, M4) and impulse (T1, T2-5, M1, M2, M5, MH) among nationality groups (P<0.05). (3) Arch index, peak force (T1, T2-5, M2), and impulse (T1, T2-5, M1, M2, M4, M5) are significantly correlated with nationality. There is significant difference in plantar pressure test indicators between Tibetan and Han nationality, and the distribution pattern of plantar parameters varies among different regions. The unique characteristics were found in the plantar pressure distribution of healthy young people from two nationality groups.
The memory of blue calico is rooted in the Jiangnan Valley. The printing and dyeing technique of blue calico is not only the cultural symbol of the city, but also the concrete carrier of Jiangnan culture. From the perspective of Jiangnan culture, this paper further explores the characteristics and origins of the poetic culture of Jiangnan, and applies the aesthetic style of Jiangnan art to the innovative design of leather products by analyzing the historical origin and artistic characteristics of the printing and dyeing technology of Nantong blue calico. Through the process experiment and design innovation, combined with the design characteristics of modern fashion women's bags and the aesthetic characteristics of contemporary women, we create humanistic clothing products with the cultural context and emotional temperature of Jiangnan cultural heritage, and provide a new reference for the cultural blending path of leather products design.
"Chaoyuan Map" is a mural work more than 600 years ago, and it is an unparalleled work in the history of Chinese painting. This article starts from the costume pattern of the characters in the fresco of Chaoyuan Tu, and deeply explores the cultural connotation and artistic value of the costume pattern. From the angle of modern design, this paper analyzes the historical background, artistic characteristics and inheritance value of the costume patterns of characters in “Chaoyuan Tu”, and elaborates the extraction method of the costume patterns of characters in “Chaoyuan Tu”. In the process of innovative design of characters' clothing patterns in "Chaoyuan Tu", combining with contemporary aesthetic consciousness, the clothing patterns with innovative genes are successfully applied in the design of modern leather women's bags. This article deeply analyzes the practical links of modern leather women's bag design, and summarizes the effective design schemes generated in the practical links. These successful application experiences can inspire the wisdom of modern designers.
Lacquer painting crafts is an ancient traditional Chinese cultural craft with both unique artistic and cultural value. This paper introduced the techniques and characteristics of lacquer painting crafts, discussed the techniques, forms and limitations involved in the application of this technology in the design of leather goods, expounded the possibility and operation methods of combining the two, and explored the development direction of traditional lacquer painting crafts in contemporary innovative applications. This work provides reference for the combination of traditional lacquer painting crafts and leather good design, excavates new development paths, and promotes the marketization, artistic and ecological transformation of traditional handicrafts.
In the context of globalization, the brand image of Chinese leather goods plays a significant role in enhancing its brand competitiveness and expanding international markets. By adopting the Grounded Theory methodology, this research utilized two approaches, namely web scraping and in-depth interviews, to gather consumer evaluations of Chinese leather goods. Based on the collected data, a three-level coding analysis was conducted, resulting in 277 basic concepts, 26 primary categories, and 7 main categories. Furthermore, the relationships between concepts and categories were examined, leading to the identification of 4 overarching core categories, namely consumer perception and identification of product quality, consumer perception of company reputation, emotional connection between brand and consumers, and consumer profiling in the Chinese leather goods market. Subsequently, a brand image model for Chinese leather goods was constructed based on these core categories, forming the theoretical framework for understanding and shaping the brand image of Chinese leather goods. Finally, recommendations for leather goods companies to effectively shape their brand image were proposed from a corporate perspective.