Browsing by Author "Wijethunge, G.P.R.D."

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    Comparison of Properties of Vegetable Tanned Leather made from Imported Mimosa and Locally Available Tanning Agents
    (Uva Wellassa University of Sri Lanka, 2013) Wijethunge, G.P.R.D.; Samaraweera, A.M.; Tharangani, R.M.H.; Wickramasinghe, W.
    Leather is a product produced by skins and hides that have been treated to preserve them and make them suitable for use. Leather is a major by-product of meat industry. In Sri Lanka, buffalo, cow and goat hides are used mainly for leather industry producing leather products such as shoes, bags, belts. There are two methods of tanning used in leather production such as vegetable tanning and mineral tanning. In vegetable tanning, plant extracts are used as tanning agent/ tannin and mimosa, an imported product at a high cost is used. In vegetable tanning process there are two types of tannin as catechole and pyragallol (Reed, 1972). Mimosa and tea waste contain catechole tannin and king coconut contains pyragallol tannin. This study was undertaken to find out the properties of locally available tanning agents as an alternative for leather tanning compared to commercially used mimosa. Methodology This study was carried out at the Ceylon Leather Products PLC, Mattakkuliya. Laboratory analysis was done at CLP and Uva Wellassa University laboratories. Cow and buffalo hides were used separately for the leather tanning process. Three tanning agents, mimosa powder, tea waste extract and extract from king coconut husks were used as treatments with three replicates for each treatment. her production process (tanning, bleaching, fat liquoring, drying and plating) was carried ). Tannin extraction from both tea waste and king coconut husk was done manually. King coconut husk was chopped to get tannin extract and tannin density was increased by boiling. Tea waste was boiled to extract tannin from the waste and increased density using high amount of tea waste. During tanning period density and pH of tanning media were adjusted at four days intervals according to the requirement. Tanning penetration and pH changes of the media was measured. Yield, thickness reduction, water absorption, hardness, shrinking temperature and tensile strength were measured in final leather. The sensory evaluation for softness, fullness and overall acceptability of final leather was done using 10 trained panelists. The sensory data were analyzed using non-parametric procedure, according to the Friedman test using Minitab 16 software. Complete Randomized design was conducted and data from tannin absorption, pH changes and properties of leather were analyzed using analysis of variance (ANOVA) procedure of Minitab 16 software. Tannin absorption was different with treatments. Mimosa has the highest absorption rate both in cow and buffalo hides (Figure 1). However, absorption rate was low compared to other day. But considering tea and king coconut it absorption was low at the beginning and then gone high and again low with the time (Figure 2). That could be due to type of tannin and purity of them.
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    Comparison of Properties of Vegetable Tanned Leather Made from Imported Mimosa and Locally Available Tanning Agents
    (Uva Wellassa University of Sri Lanka, 2013) Wijethunge, G.P.R.D.
    Leather is a product produce by skins and hides that have been treated to preserve them and make them suitable for use. It is the major by product of meat industry. Leather industry is a popular industry not only in Sri Lanka but also all over the world. Buffalo, cow and goat skins are used for leather tanning process in Sri Lanka. Shoes, bags, belts are the some leather products. Tanning is the process that converts the protein of the raw hide or skin into a stable material which suitable for a wide variety of end applications. There are two methods of tannin as vegetable tanning and mineral tanning. Vegetable tanning is done using tannin naturally occurs is plants. Mimosa is one of the commercially available tanning agent uses in leather tanning. In this study, locally available tanning agents were introduced. Tanning medias were prepared using mimosa as treatment 1, king coconut extraction as treatment 2 and tea waste extraction as treatment 3. Cow and buffalo hide tanning was conducted separately for leather production. During tanning period tanning absorption was measured. Properties of final leather, yield, hardness, thickness reduction, water absorption, shrinking temperature and tensile strength were measured. Sensory evaluation for the leather conducted for softness, fullness and overall acceptability. According to the statistical analysis for the cow leather there is no significant difference (P>0.05) between treatments with yield, water absorption, tensile strength and there is a significant difference (P<0.05) between treatments with hardness, thickness reduction and shrinking temperature. Considering properties of buffalo leather there is no significant difference between treatments with tensile strength and there is a significant difference between treatments with hardness, water absorption thickness reduction and shrinking temperature. Though there is a signific4nt difference, treatment 2 shows the better results. Therefore king coconut extraction can be used for the vegetable tanning of leather instead of the mimosa. Key words: Leather tanning, Tannin, Tea waste, King coconut, properties of leather