Leather and Footwear Journal

Volume 16, no 3

Contents
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Validation of Method for Identifying Aromatic Amines from Dyed Leather
- Pages 183-198
  Ciprian CHELARU*, Gabriela MACOVESCU, Marian CRUDU, Dana GURĂU
  - INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, Bucharest, Romania, icpi@icpi.ro
  ABSTRACT. The use of chemicals to obtain semi-processed leather must be consistent with the environmental laws and regulations, which requires evaluation of toxicity in leather goods intended for consumption. The paper proposes to implement and validate an instrumental analytical method to determine azo dyes in leather. The presence of azo dyes was determined on a total of three restricted aromatic amines (4-aminobiphenyl, benzidine, 5-nitro-o-toluidine), which can be found as a result of the split of dyes used in leather dyeing. Validation parameters of gas chromatographic method were: accuracy (trueness and reliability), precision, sensitivity, limit of detection, limit of quantification, working range, linearity.
  
  KEY WORDS: method validation, azo dyes, leather, benzidine, 4-aminobiphenyl, 5-nitro-o-toluidine
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Influence of Treads Groove, Hardness and Contaminants on the Slip Resistance of Outsole of High-Heeled Shoes
- Pages 199-210
  Ying SONG^1,2, Haojun FAN^1,2, Bo XU^1,2, Sijia REN¹, Jianxin Wu³, Jin ZHOU^1,3*
  - ¹National Engineering Laboratory for Clean Technology of leather Manufacture, Sichuan University, Chengdu 610065, P.R. China, zj_scu@qq.com
  - ²Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, Chengdu 610065, P.R. China
  - ³Science Lab, Zhejiang Red Dragonfly Footwear Co., Ltd., Wenzhou 325105, P.R. China
  ABSTRACT. The aim of this study was to explore the interaction effects of hardness (75A, 80A, 90A), structures of tread groove (spacing, width, depth and orientation) and contaminants (dry, wet and vegetable oil) on coefficient of friction (COF) of TPU outsole of high-heeled shoe, by application the SATRA whole shoe tester with normalized ceramic tile. Results of univariate analysis show that (1) in the dry condition, orientation of tread groove was the main factor impacting the COF of TPU outsole; (2) 'Orientation * contaminant', 'Hardness * contaminant' and 'Orientation * hardness * contaminant' had significant interaction impact on COF; (3) COF at the hardness of 80A was lower than that of 70A and 90A in the dry condition; while, those in the wet and oil conditions were controversial. Overall, variables of hardness, contaminant and orientation of tread groove were main influence factors in terms of slip resistance.
  
  KEY WORDS: coefficient of friction, hardness, contaminants, tread groove
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Investigation of Chrome-Greasing Diffusion into the Sheepskin Structure
- Pages 211-228
  Dmitry SHALBUEV*, Yulia KALASHNIKOVA, Sergey POLOMOSHNIKH, Elena LEONOVA
  - East Siberia State University of Technology and Management, 40 V Kluchevskaya St., Ulan-Ude, 670013, shalbuevd@mail.ru
  ABSTRACT. The authors have studied chrome-greasing fluid diffusion into the sheepskin structure by scanning electron microscopy. The results confirm the even distribution of chrome tanning components in the structure of semi-processed sheepskin during ageing for 2 hours. The quality of the finished product, produced according to the innovative technology of combined tanning and greasing with integrated mechanical processing, meets the regulatory requirements of TRCU 017/2011 On the safety of products of light industry. The proposed innovative method of tanning and greasing fluid diffusion into sheepskin structure can significantly reduce processing time of semi-finished sheepskin from 4 hours to 4.5 minutes, ageing time from 4 to 2 hours and considerably reduce water consumption and, thus, decrease toxic effluents emission containing trivalent chromium.
  
  KEY WORDS: tanning and greasing, chrome-greasing emulsion, leather, diffusion, scanning electron microscopy
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Product of Batik Ikat Motif on Leather in Sumbersekar, Dau Malang, Indonesia
- Pages 229-236
  Wehandaka PANCAPALAGA*
  - Faculty of Agriculture and Animal Science, Malang Muhammadiyah University, Jl. Raya Tlogomas 246, Malang 65148 Indonesia, pwehandaka@yahoo.com
  ABSTRACT. The study aimed to describe the product of batik ikat on leather generated by people of Sumbersekar, Dau, Malang, in terms of process, motifs and color quality. The type of research is qualitative. The collected data are about process of making batik ikat motif on tanned leather by people of Sumbersekar village and quality of its products that is obtained by observation, interviews, and laboratory analysis. Data analysis techniques are using data presentation and draw conclusions or verification. The results showed: 1) process of making leather with batik ikat motif on it is started by making the design, pattern, transferring the pattern onto the leather, binding and coloring using dye technique. To create texture of its motif, people use pebbles and small pieces of bamboo tied to the leather and use tie dye technique and spray technique for the coloring, both techniques combined with wax coating; 2) the batik motifs made by people of Sumbersekar are inspired by environment in their village, such as leaves, flowers, etc. The motifs commonly made in Sumbersekar are parang bunga, wiru jumputan, bunga jumputan, and wiru bunga, those are made by ikat system and jumputan technique; 3) the colors applied to the tanned leather with batik ikat motif are synthetic dyes based on naphtol. Quality of the tanned leathers adhesion strength of paint is 180.16 gram/cm2 with the assessment of leaching resistance, perspiration resistance, scrub resistance, and resiliency durability, are about 5. It means that quality of tanned leather with batik ikat motif produced by people of Sumbersekar is very good.
  
  KEY WORDS: tanned leather, batik ikat, Sumbersekar, Dau Malang
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Foot Pressure Characteristics of Chinese Overweight and Obese Children during Gait
- Pages 237-252
  Shiyang YAN¹, Linshan ZHANG², Xiaoyun LI², Ruoyi LI², Nan ZHOU¹, Xiaoyue CAI³, Luming YANG¹*
  - ¹Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu, China, yangluminglulu@qq.com
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Chengdu, China
  - ³The First Peoples Hospital of Shuangliu County, Chengdu, China
  ABSTRACT. There are differences in foot pressure characteristics depending on ethnicity. This is the first study to evaluate dynamic plantar pressures of overweight children, not only obese children in China, which can provide the pressure patterns of Mongoloid population with data references. Totally 438 children, including 228 boys and 209 girls, aged 7-16 years were recruited from China. Data of plantar pressures was collected by Footscan® plate system. All subjects were classified into groups of non-overweight, overweight and obesity based on body mass index (BMI). Overweight children displayed significantly higher peak pressures and impulses in the 4th metatarsal, midfoot and heel relative to non-overweight children (p < 0.017). Elevated impulses and pressure-time integrals of obese children were found at the hallux when compared to non-overweight counterparts (p = 0.017). Pressure rates were higher in obese children on the metatarsals (p < 0.017). Excessive and repetitive overload for children can increase the risk of foot damage. Since significantly higher pressures at the hallux for obese children were found for the first time, we theorize that races and customs may affect the biomechanical function of the hallux or alter the walking habits of obese children rather than the skeletal structural changes responsible for this finding.
  
  KEY WORDS: overweight; obesity; Chinese; children; dynamic plantar pressure
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