QUALITY ASSESSMENT OF THE HIDES AND SKINS AT WET BLUE STAGE AND ESTIMATING SOLID LEATHER WASTE TOWARDS VALUE ADDITION INITIATIVE IN ETHIOPIA
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Date
2019-08
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Abstract
This study was conducted to identify major defects of hide and skins and assess their impact
on the quality of the products, estimate the solid wastes generated from the sector
and identify possibilities for transforming such waste in to value added consumer products.
The study was held in eight selected tanneries in and around Addis Ababa within a
radius of 100 km. Observational survey was conducted in three potential shoe factories
and two year data from Pitards garment & goods manufacturing industry were collected
to estimate the volume of waste generated. composite leather boards were prepared using
finished leather wastes and different plant fibers namely enset (Ensete ventricosum), hibiscus
(Hibiscus cannabinus), jute (Corchorus trilocularis L.), palm (Phoenix dactylifera)
and sisal (Agave sisalana) employing different binders like natural rubber latex (NRL),
Resin binder (RB), and Poly urethane binder (PUB). These materials were incorporated
in different proportions and their products were characterized for their mechanical and
physicochemical properties. The Defects of hides and skins were categorized into pre-,
peri- and post-slaughter problems. The overall prevalence of these defect categories were
81.80% in pre-slaughter, 59.90% in peri-slaughter and 27.80% in post-slaughter in hides.
The corresponding values for sheepskin were 87.00%, 36.70%, 32.90%, respectively.
About 70.00, 75.30, 27.20% of goatskins had defects at the pre, peri and post slaughter
stages respectively. Grade values of hides and skins in this study showed that most
grades fall in grade 5, 6 and rejects (7) showing that the quality of the raw materials is
getting worse than ever due to the effect of defects occurred as pre slaughter mainly of
(cockle, scratch, scar), peri slaughter (mainly flaying defects) and post slaughter (mainly
putrefaction) that are taking greater share and responsible for the quality deterioration
of the raw materials. Composite leather boards prepared using NRL as binder exhibited better mechanical
properties compared to those of control boards. Composites prepared using resin binder
(RB) and Poly urethane binder (PUB) have shown better tensile strength properties than
their respective controls revealing the compatibility of the resin binder with plant and
leather fibers. SEM pictures of the products in this study showed composite nature. In
composite sheets prepared using RB having 10 % hibiscus, 20 % palm and 40 % sisal
fibers showed better mechanical properties than their controls. In those composite sheets
made using NRL having 30 % jute fiber exhibited better mechanical properties than its
control and meet the required standards for insole/shank board, though has lower values
of tensile strength in wet state than its control. Most of the plant fibers used in this study
played a role in improving properties of the sheets though it is dependent on the ratio
used and the nature of the binder. It was observed that all of the composite sheets prepared
in this study can be used as raw material for the preparation of consumer products
such as insoles, chapel-uppers, light hand bags, false roofing coverage, mouse pads, key
chains, wallets, components of furniture and other interior decorations.
Description
PhD Thesis
Keywords
Ethiopia, Hide & skin, leather waste, composite