Forming of the dermis structure with using of mineral compositions based on zeolite and montmorillonite for shoe leather

Transcription

1 2 nd International Conference Science for Business: Innovation for textiles, polymers and leather Forming of the dermis structure with using of mineral compositions based on zeolite and montmorillonite for shoe leather Oksana Kozar Mukachevo State University Katarzyna Ławińska Instytut Przemysłu Skórzanego Łódź,

2 INTRODUCTION Expanding the range of special shoes and improving their functional and performance requirements lead to a searching for new technological solutions. Nowadays the most promising, environmentally appropriate and economically sound solution of technology for leather industry is the formation of structure and properties of leather materials using composite materials based on natural minerals. A promising direction in the tanning industry is using of technologically efficient and ecologically friendly materials based on naturally occurring minerals.

3 CHARACTERISTICS OF THE ZEOLITE AND MONTMORILLONITE CRYSTAL STRUCTURE The frame structure of zeolite is given by general formula: (Me,O)(Al 2 O 3 )(SiO 2 )m nh 2 O. Physical and chemical characteristics, especially high thermal stability, suggest that as the modifier it will increase the heat resistance performance of adhesive joints. Porosity 34% Density 2,3g/cm 3 Specific surface area 413m 2 /g Content of the sorbent 70% Ion exchange capacity 1,5mg eq/g Humidity 4 6% Thermal stability up tо 700 С Size of micropores 0,3-2 nm Powder dispersion 0,08mm Cost 50 /t Frame-crystal lattice structure of zeolite. Zeolite has a solid frame tetrahedral skeleton with a system of cavities and channels.

4 Montmorillonite is a widespread clay mineral from the group of layered silicates. A characteristic feature of layered clay minerals in nature is the high dispersion; particle size is usually less than 1-10 microns. Montmorillonite - by the nature of the crystal lattice refers to a clay layered hydrated silicate of alumina of lamellar structure. The total active surface of montmorillonite ( m 2 /g) is a sum of external and internal area of basal planes. general formula (Na,Ca) 0.33 (Al,Mg) 2 (Si 4 O 10 )(OH) 2 nh 2 O

5 AIM OF RESEARCH The aim of this research is to establish and analyze properties of natural leather, filled with minerals during re-tanning processes. The second point is a prediction of their shape memory effect. Modified dispersions of natural MDM (mineral modification of montmorillonite) and MDZ (mineral modification of zeolite) in concentrations of 3% and 4% were used. Modification of montmorillonite and zeolite was performed with sodium polyphosphate in the amount of 10% by weight of dry mineral.

6 TESTING METHOD AND MATERIALS Chrome semi-finished product from cattle raw material (thickness 1,2 1,4mm), outgrowth (thickness 1,1 1,3mm) and pig leather lining (thickness 0,6 0,8mm) has been used for testing as objects of research. Experiments were conducted in accordance with standards concerning the discussed issues.

7 The main role of minerals in shaping the leather structure is: screening of functional groups and structural elements of the dermis collagen; preventing their gluing; making compact of different regular levels and topographical areas; creation of additional active sites of interaction with other chemical materials; forming the bulk structure of the leather.

8 Indicators of structure formation of the dermis after the mineral filling Index of semifinished product МDМ МDZ MDM MDZ FTG Output, % area 105,1 103,1 103,9 100 thickness 114,4 115,4 114,7 100 Porosity, % back 55,3 49,1 48,7 46,9 belly 58,1 53,2 60,2 52,6 Humidity, % back 13,66 14,30 13,97 13,46 belly 13,68 13,68 13,06 14,00 Content of back 74,03 73,31 72,80 74,00 clay, % belly 67,90 68,17 64,80 72,57 minerals 8,1 8,4 8,2 5,7 chromium Content,% of oxide 3,6 3,7 3,5 3,6 dry substance substances extracted from organic solvents 4,6 4,9 5,1 4,5 Volumetric yield, cm 3 /100g protein 340,9 322,4 334,9 324,3

9 Moisture exchange, %, Moisture exchange, % Hygroscopicity, % Hygroscopicity, % Waterproof and hygroscopic properties of leather with mineral content for uppers shoe for leather lining MDM MDZ MDZ:MDM FTG

10 Moisture soaking static dynamic ,2 12,4 16,1 MDM MDZ MDZ/MDM FTG FTG MDZ:MDM MDZ MDM Adsorption of water, %

11 Water capacity, % Getting wet, % MDM MDZ MDZ/MDM FTG 2h 24h MDM MDZ MDZ/MDM FTG 2h 24h

12 Indicators of thermal stability of leather with mineral content Indicator МDМ МDZ MDM MDZ FTG Welding temperature, 0 С рн KCl extraction 3,6 3,6 3,6 3,3 Burning resistance with hot metal, s/mm 6,5 6,1 8,8 5,6 Heat exposure resistance (200 0 C, τ=15 min.) of leather in air-dry condition,% 21,8 16,1 8,7 20,7

13 The dependence of the square sample of leather surface temperature The temperature of the hot surface Change in sample area after contact with a hot surface Tanicor FTG MDM MDZ MDM:MDZ control mm 2 % mm 2 % mm 2 % mm 2 % С 8,7 1,5 2,95 0,5 4,87 0,5 2,9 0, С 15,4 2,7 25,3 4,4 14,4 4,4 25,1 4, С 27,5 4,9 37,2 6,62 31,9 5,7 37,2 6, С 97,9 17,2 53,7 9,7 69,3 12,3 98,5 17,3

14 DTG, mv Differential thermogravimetric curves of the samples of filled skin. FTG MDM MDZ MDZ:MDM DTA, mv T, C Differential thermal curves of the samples of filled leather. T, C

15 The thickness of leather for uppers after mineral filling FTG MDZ:MDM MDZ MDM back part peripheral areas 0,5 0,7 0,9 1,1 1,3 1,5 The thickness increase after filling The thickness increase* after filling process МDМ МDZ MDM overall increase in the thickness of the area, % MDZ 14,4 14,4 14,7 total area of the skin growth, % 3,1 5,1 5,1 *regarding to the control samples

16 The coefficient of uniformity with reference to the mechanical properties of leather area In order to estimate the degree of anisotropy in the skin, let s put the K u, which is uniformity coefficient of leather. It describes the anisotropy in the leather and depends on relaxation and deformation properties. FTG MDZ:MDM K u transversal longitudinal MDZ MDM 0,7 0,8 K u 0,9 1 tensile strenght relative elongation at breaking point relative elongation at 10 MPa

17 Relative deformation, % This figure presents the relative deformation dependence in the function of type of deformation for the mineral filler. Types of deformation, % When zeolite dispersions are used as a filler, an increase of particles and residual elastic strain is observed. It indicates a high ability of skin to shaping and ability to shape memory effect. As a consequence, it reduces a elastic modulus and makes increase of hardness.

18 Stability, % Absolute elongation, mm Linear characteristics curve of modified skin samples (after removal) under the load over time and the rate of shape stability show a positive effect of the mineral content of semifinished leather on the relaxation and deformation characteristics of the leather for upper shoe. Filler Full deformation, % Plasticity, % МDZ 30,0 60 МDМ 31,5 52 МDZ:МDМ 31,1 57 FTG 29, FTG, 2 MDM, 3 MDZ ,4 94,6 90,1 85 MDM MDZ FTG Duration, min

19 Physical and mechanical properties of semi-finished leather with mineral filling Properties МDМ МDZ MDM MDZ FTG Breaking load, ± Tensile strenght, MPa 36,0 35,0 34,0 33,0 Elongation, % -at 10 MPa 32,7 27,3 28,3 29,6 -at breaking point 56,7 51,7 53,7 59,0 The conventional modulus of elasticity, MPa 34,4 31,8 33,2 32,3 Stiffness 21,5 25,1 23,6 22,2 Total deformation, % 23,4 22,4 21,7 22,3 Vapour permeability, mg/cm 2 h 10,8 8,5 9,4 9,0 Vapour permeability coefficient, mg/cm 2 94,5 78,4 82,4 87,7 Air permeability, cm 3 /cm 2 h 870,0 824,0 890,0 780,0

20 CONCLUSIONS 1. Taking into account the physical and mechanical characteristics of modern natural and synthetic materials, their hygienic properties and economic effect of the use of them, we can conclude, that the leather for shoe uppers and rubber for the sole shoe still remains the most suitable in all respects for the footwear manufacturers. 2. Deformation properties are the most important of leather materials, because they determine the quality of basic technological operations of shoes, which determines the convenience of the product and shape retention during operation. 3. The results indicate the feasibility of using animal leather with mineral filling for making comfortable, environmentally friendly shoes for special purposes with high humidity, water, thermal and fire retardant properties. 4. The results of research can offer new competitive leather materials, which could be implemented in shoe production for special purposes.

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