Leather and Footwear Journal

Volume 22, no 4

Contents
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ABLATION METHOD OF GRINDING A LEATHER SPLIT UNDER THE INFLUENCE OF LASER RADIATION
- Pages 249-256
  Gulnoza JUMAYEVA¹, Mariya MARKEVICH², Akmal TOSHEV¹, Tulkin KODIROV¹, Shokhrukh SHOYIMOV³
  - ¹Tashkent Institute of Textile and Light Industry, 100100, Shohzhahon-5, Tashkent, Republic of Uzbekistan, e-mail: akmal-toshev-yu@mail.ru
  - ²Physical-Technical Institute of the NAS of Belarus, 220141, Academician Kuprevich street 10, Minsk, Belarus, 712518272
  - ³Bukhara Engineering – Technological Institute, 200100 Bukhara, Republic of Uzbekistan, e-mail: shoyimoshsh@mail.ru
  ABSTRACT. Using scanning electron microscopy, the surface morphology of a split leather sample was studied under the action of laser radiation from the front and backsides. It has been established that the effect of laser skin resurfacing is achieved in the range of input energies of 40 J and exposure times of 40 sec. It was found that laser exposure from the front and backsides leads to polishing of splits. Skin resurfacing from the front and leather split starts at different input energies from the front side from the split, which is associated with a looser structure of the leather from the split and its lower absorption of radiation.
  
  KEY WORDS: leather tissue, pigment concentrate, protein, acrylic aldehyde, copolymer emulsion of butyl acrylate, methyl methacrylate and acrylic acid, coating dyes, laser radiation, diffusion, split leather surface structure, collagen fibers, elemental analysis, hygroscopicity, moisture return
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THE INFLUENCE OF PROTEIN AND ELASTOMER WASTE MIXTURE ON THE NBR-BASED ELASTOMER COMPOUND
- Pages 257-266
  Mihaela NIŢUICĂ (VÎLSAN)*, Maria SÖNMEZ, Maria Daniela STELESCU, Laurenţia ALEXANDRESCU, Mihai GEORGESCU, Dana GURĂU, Elena BADEA, Bogdan Florin RUSU, Andrei DUMITRU
  - INCDTP – Division Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest, mihaela.nituica@icpi.ro, mihaelavilsan@yahoo.com
  ABSTRACT. The paper presents the influence of a mixture of elastomeric and protein waste from the footwear industry on the properties of elastomeric compounds based on NBR (butadiene-co-acrylonitrile) rubber, as well as their obtaining and characterization. The mixture of leather and rubber waste was cryogenically ground, in three grinding cycles, and the selected size was 0.35 mm, and the rotation speed of 14,000 rpm. After grinding, the leather and rubber waste mixture was functionalized with potassium oleate at a temperature of 60°C. The polymer compounds based on butadiene-co-acrylonitrile rubber (NBR) and the mixture of protein and elastomeric waste (in the ratio of 15, 20, 40, 50%) from the footwear industry were processed by mixing on an internal Brabender mixer, tested from a rheological, physical and mechanical point of view (hardness, elasticity and tensile strength) after conditioning for 24 h at room temperature according to the standards in force, but also by FT-IR spectroscopy performed with a double beam IR molecular absorption spectrometer, in the range 4000- 400 cm-1, using the FT-IR Thermo Nicolet iS 50, equipped with ATR with diamond crystal. Following characterisation, it can be said that they present optimal values that fall within the standards for the footwear industry.
  
  KEY WORDS: elastomer, protein and elastomeric waste, composite, vulcanisate, compound
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CITRIC ACID AS AN EFFECTIVE AND SAFE FIXING AGENT IN VEGETABLE TANNING PROCESS OF GOATSKIN
- Pages 267-274
  Nur Mutia ROSIATI*, Mustafidah UDKHIYATI
  - Department of Leather Processing Technology, Politeknik ATK Yogyakarta, Sewon, Bantul 55188, Yogyakarta, Indonesia, mutiarosiati@atk.ac.id
  ABSTRACT. Formic acid is known as a fixing agent in vegetable tanning process but this material is corrosive and irritant. Citric acid has the potential to be developed as an alternative fixing agent. This research aims to study the ability of citric acid as an alternative fixing agent in the tanning process, especially vegetable tanning of goatskin. The tanning process was carried out by the drum method. Pickled goatskins were tanned with mimosa and then fixed with citric acid. The concentration of citric acid varied from 1%; 1.5%; 2%; 2.5%; to 3%, to determine the optimum concentration. A fixing agent of 2% formic acid was used as a control. The results show that the control skin had similar characteristics to the treated skin. Physical properties of T4 have met the standard of SNI 0253-2009. It can be concluded that the optimal concentration of citric acid that can be used as an alternative fixing agent in vegetable tanning process of goatskin is 2.5%.
  
  KEY WORDS: tanning, skin, fixing agent, citric acid
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TESTING OF MEDICAL SHEEP FUR WITH ANTIMICROBIAL PROPERTIES – PART 2
- Pages 275-282
  Olga NICULESCU*, Rodica Roxana CONSTANTINESCU, Dana GURĂU
  - INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., Sector 3, Bucharest, Romania, e-mail: o_niculescu@yahoo.com
  ABSTRACT. There are a number of people with rheumatic, joint and muscle diseases, and the medical treatment of patients suffering from these diseases requires an improvement through alternative methods. Pain is the main symptom of rheumatic diseases and chronic pain affects the physical and mental condition, lowering quality of life and ability to work. Natural products derived from plants with antimicrobial, anti-inflammatory, antioxidant, and chemo-preventive properties have been used for many generations in traditional medicine. The essential oils extracted from different plants have certain analgesic, anti-inflammatory, antiseptic, antibacterial, immunostimulating properties, etc. Products have been made based on essential oils with therapeutic properties (daphne, ginger, basil), which can be used to treat the surface of tanned sheep fur for medical purposes. Ecological requirements have led to the development of new fur processing technologies, such as wet-white tanning of fur to eliminate or reduce the amount of complex salts of trivalent chromium. The sheep furs were tanned (without metals) with syntans based on phenolsulfonic acids and aromatic oxysulfones and treated with products based on essential oils with therapeutic properties, to be used to make medical fur articles (lumbar and cervical belts, knee pads, elbow pads, bootees, etc.). They can improve rheumatic, muscular and circulatory conditions, complementing the medical treatment of patients suffering from these conditions. Heat can relieve rheumatic pains (transmitted through the application of natural fur). The work presents the chemical, physical-mechanical and microbiological characterization of natural furs for medical use.
  
  KEY WORDS: medical fur, essential oils, antimicrobial properties
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