Leather and Footwear Journal

Volume 17, no 2

Contents
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Advantages of Utilizing Microwave in Soft Leather Drying
- Pages 81-86
  Jinwei ZHANG^1,2, Changlong ZHANG¹, Jiacheng WU^1,2, Wuyong CHEN^1,2
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Chengdu, 610065, China
  - ²Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, Chengdu, 610065, China
  ABSTRACT. The leather was dried by microwave and compared with the leather dried by oven in mechanical properties, softness, shrinkage temperature, microstructure as well as uniformities of chrome tanning agent, fatliquoring agent and dyestuff as new method for soft leather drying to keep and improve its softness and comprehensive properties. The results indicated that microwave drying would not damage leather collagen structure. Meanwhile, as microwave drying was even and would promote the combinations of collagen with other chemicals, the softness and mechanical properties of microwave dried leather were improved, in addition, the shrinkage temperature and uniformities of chrome tanning agent, fatliquoring agent and dyestuff were also promoted. Moreover, much more orderly and porous arrangement but less adhesion in collagen matrix of microwave dried leather were observed. These phenomena illustrated microwave dried leather could meet the high quality demands of leather better in softness and uniformity. To sum up, microwave has many advantages in drying soft leather products.
  
  KEY WORDS: microwave, garment leather, dry process, softness, uniformity
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Study on Plant Growth Promoter from Proteineous Wastes from Leather Industry
- Pages 87-90
  Victor JOHN SUNDAR*, Govindaswamy RAMAMURTHY, Thotapalli Parvathaleswara SASTRY
  - CSIR-Central Leather Research Institute, Adyar, Chennai - 600020, Tamil Nadu, India, e-mail: johnsundar70@yahoo.co.uk
  ABSTRACT. Tanneries generate huge quantities of solid wastes as fleshings. If these bio-waste materials are not utilized properly they are potential source of pollution. So in the present study it has been tried to convert these hide fleshings into NPK fertilizer. During the process of manufacture of NPK fertilizer, phosphorous and potassium were incorporated by suitable chemical reaction under desired conditions of temperature and pressure. The resultant liquid product was converted into pellet form and field tested on horticulture plants (Balsam Plant - Impatiens balsamina).
  
  KEY WORDS: animal fleshings, fertilizers, nitrogen, phosphorus, potassium
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Electrochemical Behavior of Tannin Solutions under Microwave Irradiation
- Pages 91-96
  Jiacheng WU^1,2, Li ZHANG¹, Jinwei ZHANG¹, Haibin GU^1,2, Wuyong CHEN^1,2*
  - ¹Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, P. R. China
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P. R. China
  ABSTRACT. Vegetable tannin extract has an important use as a tanning agent in leather industry. The electrochemical behavior of tannin solutions, as a critical factor, greatly affect vegetable tanning. In this work, we have investigated the particle size, Zeta potential and conductivity of Commercial Acacia Mangium extract solutions (CAME) and Commercial valonia extract solutions (CVE) under water bath heating (WBH) and microwave irradiation heating (MIH). The heating conditions were selected as follows: time, 5 min, 15 min, 30 min, 60 min and 120 min; temperature, 30°C, 40°C and 50°C. It was found that the particle size of both CAME and CVE decreased under MIH while Zeta potential increased compared with WBH. Furthermore, the features become more and more significant with the irradiation temperature and time. And the conductivity of CAME and CVE increased more with the temperature under MIH in comparison to WBH. As a result, in the condition of microwave irradiation, tannin extract can easily penetrate into skins and then crosslink well with the collagen owing to the small tannin particle size and stable solution system, hence microwave may contribute to the penetration of tannin extracts in the skin and the binding properties with collagen in vegetable tanning.
  
  KEY WORDS: dynamic light scattering, electrochemical behavior, microwave irradiation, vegetable tannin extract
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Application of Lac Dye in Shoe Upper Leather Dyeing
- Pages 97-106
  Amal Kanti DEB¹*, Md. Aftab Ali SHAIKH¹, Md. Zakir SULTAN², Md. Israil Hossain RAFI¹
  - ¹Institute of Leather Engineering and Technology, University of Dhaka, Dhaka-1209, Bangladesh
  - ²Centre for Advanced Research in Sciences (CARS), University of Dhaka, Dhaka-1000, Bangladesh
  ABSTRACT. Shoe upper leather samples were dyed with the natural lac dyes (byproduct of shellac and shellac products industry) extracted from washings of the stick lac by conventional methods. The aim of this research is to utilize this dye water and reveal the novel natural recipe for eco-friendly dyeing operation of shoe upper leather processing. The extraction of lac dye was carried out by using water at different temperatures. The lac dye was applied on the leather samples with and without using mordants; and three different mordants (CuSO4, FeSO4, [KAl(SO4)2]) were used following metamordanting method of dyeing. Absorbance and λmax of all dye liquors at different time intervals were determined by UV-visible spectrophotometer. The dyestuffs exhaustion and uptake were investigated and results showed that mordanted dyeing increased the dye uptake on leather than unmordanted dyeing. The FTIR analyses samples were carried out and it was found that lac dye could be mainly composed of -OH, -NH, >C=C<, >C=O, -COOH functional groups. The fastness properties such as fastness to washing, rubbing (dry and wet) and light of prepared leather samples were assessed. The results of color fastness of the mordanted and unmordanted leather samples showed excellent (5) and best (4-5) gray scale rating respectively.
  
  KEY WORDS: Shoe upper leather, Natural dye, Lac dye, Stick lac, Eco-friendly, Mordant
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Experimental Study on Different Characteristics of Plantar Pressure Distribution in Different Sports Shoes
- Pages 107-115
  Ping WU*
  - Guizhou Medical University, Gui'an 550025, China, wp18185111579@163.com
  ABSTRACT. This paper studies the effects of sports shoes in improving people's exercise capacity and preventing sports injuries, and by performing gait (0.8m/s), jogging (1.5m/s) and moderate-speed running (2.3m/s) tests on athletes, discusses the characteristics of plantar pressure distribution on bare foot or in different sports shoes. According to the research results, when athletes are bare foot and wearing sports shoes, the heel region bears the largest pressure in both cases. When bare foot, the plantar pressure on the first toe region is also large, but when in sports shoes, the plantar pressure in this region is significantly reduced. During bare foot gait, plantar pressure is relatively concentrated in toe, forefoot and heel regions; during gait in sports shoes, plantar pressure is evenly distributed. Shoes are designed to allow the arch region to also bear some pressure so that the whole plantar pressure tends to be even. During jogging and gait, the ground reaction forces given by NIKE sports shoes to the 4 plantar regions are small, indicating that NIKE shoes provide better cushioning effects compared with the other two sports shoe brands; ADIDAS shoes provides the poorest cushioning effects - the pressure is high and concentrated in forefoot, arch and heel regions, bringing more harm to the foot arch region. The pressure brought by these 3 brands of sports shoes does not vary much in the toe bone region, but significantly in the arch region.
  
  KEY WORDS: plantar pressure, pressure distribution, sports shoes, pressure intensity, running
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