Leather and Footwear Journal

Volume 21, no 3

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EVALUATION OF ENVIRONMENTAL EFFECT OF PUMP SHOES IN TERMS OF MANUFACTURING PROCESS
- Pages 137-144
  CHI ZHANG¹, LEIYA LI¹, Carmen GAIDAU², Jin ZHOU¹*
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P.R. China; 1846119869@qq.com, 879781426@qq.com
  - ²Leather Research Department, INCDTP – Division: Leather and Footwear Research Institute, Bucharest 031215, Romania; carmen_gaidau@hotmail.com
  ABSTRACT. China is the largest footwear producing country, as well as the largest country producing the footwear manufacturing waste. In order to achieve sustainable development in the footwear industry, we should pay attention to their environmental effect seriously. Therefore, by applying life-cycle assessment (LCA) protocol, we aimed to explore the effect of the manufacturing process on the environment of a classical style of pump shoes. Following guidelines of ISO 14010, we first determined the objective and the scope of this study; then, we collected input and output data from the shoe producing line of a shoe-making enterprise in Wenzhou, China; afterwards, we applied eFootprint software for LCA modeling; finally, we chose three LCA indicators for further analysis: Global Warming Potential (GWP, kg CO₂ eq), Primary Energy Demand (PED, MJ) and Abiotic Depletion Potential (ADP, kg Sb eq). Our results show that by producing one pair of pump shoes, the manufacturing process will emit 11.427 Kg CO₂ eq in terms of GWP, 232.621MJ in PED and 6.291×10-5Kg sb eq in ADP. Hence, by multiplying the number of shoes produced in China, negative environmental influences from shoe making industry were also dramatic. According to further contribution rate of all process, we found that materials such as the water-based binder and the plastic last used in manufacturing process accounted for the major reason. Overall, while considering the environmental effects from the shoe manufacturing process, we shall not ignore the environmental impact whilst producing the binder and the last. Moreover, by reducing binder usage or updating the shoe making technology, and recycling the last can be an efficient way to reduce the environmental effects from the shoe making industry.
  
  KEY WORDS: shoe making process, life cycle assessment, polyurethane synthetic leather, pump shoes
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ANALYSIS OF VARIATION OF THE SKIN SUBSTANCE WITH THE APPLICATION OF DIFFERENT ACIDS IN THE PICKLE STAGE IN ECUADORIAN SERRANO BOVINE LEATHERS
- Pages 145-158
  Mabel PARADA^{1, *},Robert CAZAR², David ESPIN³, Alexandra TAPIA⁴
  - ¹Research Professor, Higher Polytechnic School of Chimborazo (ESPOCH), Faculty of Sciences, Chemical Engineering Career, Riobamba, Ecuador, mparada@espoch.edu.ec
  - ²Research Professor, Higher Polytechnic School of Chimborazo (ESPOCH), Faculty of Sciences, Chemistry Career, Riobamba, Ecuador, robert.cazar@espoch.edu.ec
  - ³Independent Researcher in the Chemical Engineering Area of Higher Polytechnic School of Chimborazo, Ambato, Ecuador, espindavid95@gmail.com
  - ⁴Research Professor, Faculty of Agricultural Sciences and Natural Resources, Career of Agronomy, Technical University of Cotopaxi, Latacunga, Ecuador, alexandra.tapia@utc.edu.ec
  ABSTRACT. A chemical analysis was carried out to determine the content of skin substance in different leather samples prepared using several acids in the pickling stage. Ecuadorian bovine skin was utilized. It went through the tanning processes until reaching the pickling stage in which three treatments employing sulfuric acid, formic acid and oxalic acid, respectively, were applied. Later, tanning was applied, wet blue samples were obtained and their contents of skin substance were measured by means of AST D2868-17 rules. Results were verified through a statistical analysis using Infostat software. After post tanning stages a dyed leather was obtained upon which physical tests of tension resistance, elongation percent and lastometry as well as sensorial essays of feeling, softness and swelling were executed. The treatments produce results of skin substance from every leather area, that is, head, loin and backside. It is found that the sulfuric acid pickling features the highest content of skin substance (72.63%) followed by the formic acid pickling (70.94%) and the oxalic acid pickling which has the lowest amount of skin substance (65.04%). In order to validate the results, a statistical analysis was performed which confirms the chemical analysis. To ratify which one was the best treatment, a comparison based on the properties of each acid was made. The formic acid was confirmed as the most appropriate since it differentiates from the sulfuric acid due to the skin substance content by complying with the required parameters of elongation (15.89%), and softness/swelling (4%). On the other hand, oxalic acid produced lesser quality results.
  
  KEY WORDS: skin substance, type of acid, pickling, physical analysis, sensory analysis
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INFLUENCE OF SOLAR RADIATION INSOLATION PRECIPITATION ON HYDROPHOBIZED LEATHER FOR SHOE UPPERS
- Pages 159-172
  Abdujalil Mannapovich DJURAEV¹, Tulkin Jumayevich KODIROV¹, Khalil Khabibullaevich USMANOV², Akmal Yusupovich TOSHEV¹, Shohrux Shuxratovich SHOYIMOV^{3, *}
  - ¹Tashkent Institute of Textile and Light Industry, 100100, Shohzhahon-5, Tashkent, Republic of Uzbekistan
  - ²Namangan Engineering Technologies Institute 160115, Namangan, Republic of Uzbekistan
  - ³Bukhara Engineering – Technological Institute, 200100 Bukhara, Republic of Uzbekistan, e-mail: shoyimoshsh@mail.ru
  ABSTRACT. The influence of solar radiation and precipitation on leather samples for the upper part of footwear, treated with water-repellent compounds, was determined and the process of their destruction in natural atmospheric conditions was determined. The study of the effect of solar radiation on natural skin has not been sufficiently studied. In connection with the above, the test was carried out on experimental hydrophobized and initial (control) leather samples in an open area to determine the insolation of solar radiation and precipitation on the skin for the upper shoes. During the tests, a systematic examination of the exposed samples was carried out for 1-6 months, sampling for physico-mechanical and other tests was recorded by meteorological conditions. After that, the samples were subjected to organoleptic evaluation, physical-mechanical and chemical-analytical analyses, as well as structural studies. It was visually determined that, depending on the variant of hydrophobization used, fibrillar collagen formations change in different ways. After atmospheric insolation acts on the control sample, its fibrillar structure changes sharply, numerous micro cracks appear, located mainly perpendicular to the fiber axis, and clearly defined dark zones are found between the fibrils. Fibril outlines become indistinct, numerous torn ends are observed. However, such changes are not observed for hydrophobized samples. Significant changes in physical and mechanical properties are observed in the first and fourth months of natural aging. In the hydrophobized sample, the rate of change in hydrothermal destruction and the appearance of cracks in the face layer subjected to aging in an open area, is always lower compared to the control sample.
  
  KEY WORDS: hydrothermal destruction, hydrophobization, insolation of solar radiation, destruction, fibrillar structure
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THE USE OF NON-CHROME MINERAL TANNING MATERIALS AS A PREFERABLE ENVIRONMENTALLY FRIENDLY TANNING MATERIAL
- Pages 173-182
  Emiliana ANGGRIYANI, Laili RACHMAWATI, Nais Pinta ADETYA
  - Department of Leather Processing Technology, Politeknik ATK Yogyakarta, Sewon, Bantul, 55281 Yogyakarta Indonesia, emiliana.anggry@gmail.com
  ABSTRACT. Mineral chrome tanning agent is the most widely used tanning agent for various types of leather articles, given its various advantages. Besides its many advantages, there is a negative side to chrome tanneries, namely the presence of waste disposal that is harmful to the environment. Therefore, this study aims to determine the quality of mineral tanning materials other than chrome (aluminium and titanium) as a substitute for leather tanning (free of chrome). The research raw materials were 12 pieces of pickled goatskin. The chemicals used are aluminium tanning agent (Novaltan Al), titanium tanning agent, salt (NaCl), Peramit MLN, Derminol OCS, MgO, NaHCO₃, BCG indicator, Rellugan GT 50, Tanigan PAK, Lipoderm Liquor SAF, Dermagen GPA, Derminol SPE, Derminol NLM, Acid dyestuff, formic acid, Sincal DR and anti-fungal. The method used is to carry out the tanning process using aluminium tanning agents with levels of 2%, 4%, and 6% Al₂O₃, continued the combination between aluminium and titanium tanning agent. The results obtained were analyzed for the cross-sectional and content of the leather using the EDX method, a shrinkage temperature (Ts) test, and physical quality of crust skin. The results showed that the higher the Al₂O₃ content, the more Al content in the leather, but the lower the wrinkle temperature of the leather. Meanwhile, the longer the processing time, the aluminium content in the skin increases. The use of aluminium and titanium tanning agent can improve the physical quality of the skin, both in terms of tensile strength and skin softness. The conclusion that can be drawn is the use of 2% free of chrome (aluminium) tanning material can produce Ts of 71°C. The physical quality of the crust skin from aluminium and titanium mineral tanning agents is better than the single-use of aluminium.
  
  KEY WORDS: free of chrome, mineral tanning agent, aluminium, titanium
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STUDY ON THE RELATIONSHIP BETWEEN THE TOE-OUT GAIT AND FOOT HALLUX VALGUS IN THE ELDERLY CHINESE
- Pages 183-192
  Xiang-Dong LUO^{1, 2 *}, Yi-Nuo ZHANG^{1, 2}, Chao-Hua XUE^{1, 2}, Zong-Min YUE^{1, 2}
  - ¹College of Art & Design, Shaanxi University of Science and Technology, Xi’an, Shaanxi, P. R. China 710021
  - ²Shaanxi Artificial Intelligence Joint Laboratory, Xi’an, Shaanxi, P. R. China 710021
  ABSTRACT. The study selects 50 senior people at the age of more than 60 and 30 young people at the age of 18-26 as test group and control group respectively, including people with mild foot disease, such as flat feet, pes cavus and hallux valgus. Questionnaire survey of effective data volume and observation are used to understand common problems of the foot in the elderly, collect shape photos of the foot in senior people, and subjectively analyze their foot shape and gait characteristics. Footscan plate plantar pressure test system and Kistler 3D force platform are used to objectively analyze plantar pressure distribution and gait characteristics of subjects. According to study results: Toe-out gait causes the plantar pressure to move to the forefoot, therefore, the forefoot is the part with the highest risk of injury of foot in toe-out gait, especially the first toe, causing hallux valgus and various foot problems. The toe-out gait causes increase of gait cycle, slow walking speed, poor buffer effect, and may bring pain in feet and lower extremities, thus affecting the dynamic characteristics of the entire lower limb.
  
  KEY WORDS: the elderly, toe-out gait, foot hallux valgus
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